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Sample records for foraminifera amphistegina lobifera

  1. Microsensor studies of photosynthesis and respiration in the larger symbiont bearing foraminifera Amphistegina lobifera, and Amphisorus hemprichii

    DEFF Research Database (Denmark)

    Köhler-Rink, S.; Kühl, Michael

    2001-01-01

    The photosynthesis and respiration of the larger foraminifera Amphistegina lobifera and Amphisorus hemprichii was studied with O2, CO2, and pH microsensors, and with a miniature gas exchange chamber. The diffusive transport of O2 and CO2 through both perforate (A. lobifera) and imperforate (A...... ratio at the shell surface of the foraminifera was ~2 in darkness and ~6 at saturating irradiance, pointing to a large internal supply of CO2 in the host-symbiont association and the use of bicarbonate as source for inorganic carbon. The carbonate chemistry in the vicinity of symbiont-bearing larger...... foraminifera is thus strongly affected by the combined action of photosynthesis, respiration and calcification, and cannot be considered in equilibrium with the surrounding sea water. This has important implications for paleoenvironmental analysis and interpretation of the stable isotope composition...

  2. Shifts in species abundance of large benthic foraminifera Amphistegina: the possible effects of Tropical Cyclone Ita

    Science.gov (United States)

    Prazeres, Martina; Roberts, T. Edward; Pandolfi, John M.

    2017-03-01

    On the Great Barrier Reef (GBR), the large benthic foraminifera Amphistegina lobifera, A. lessonii and A. radiata occur in shallow (population-level source-sink dynamics should be considered when exploring persistence and recovery patterns over depth in foraminiferal communities.

  3. The presence of the Indo-Pacific symbiont-bearing foraminifer Amphistegina lobifera in Greek coastal ecosystems (Aegean Sea, Eastern Mediterranean

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    M.V. TRIANTAPHYLLOU

    2009-12-01

    Full Text Available During the last decades, hundreds of species of Indo-Pacific origin from the Red Sea have traversed the Suez Canal and settled in the Eastern Mediterranean. Nowadays, Amphistegina lobifera Larsen, is known to be a successful immigrant that is widely distributed in the coastal ecosystems of the Eastern Mediterranean Sea. Amphistegina is the most common epiphytic, symbiont- bearing large foraminifer. In this study we provide additional data on the presence of this species in the coastal ecosystems of Aegean Sea, Greece. The high relative abundance of A. lobifera is the result of very successful adaptation of this species to local conditions and suggests that it has become a significant part of the epiphytic foraminiferal fauna.

  4. Intra-shell boron isotope ratios in the symbiont-bearing benthic foraminiferan Amphistegina lobifera: Implications for δ 11B vital effects and paleo-pH reconstructions

    Science.gov (United States)

    Rollion-Bard, C.; Erez, J.

    2010-03-01

    The boron isotope composition of marine carbonates is considered to be a seawater pH proxy. Nevertheless, the use of δ 11B has some limitations such as the knowledge of the fractionation factor ( α4-3) between boric acid and the borate ion and the amplitude of "vital effects" on this proxy that are not well constrained. Using secondary ion mass spectrometry (SIMS) we have examined the internal variability of the boron isotope ratio in the shallow water, symbionts bearing foraminiferan Amphistegina lobifera. Specimens were cultured at constant temperature (24 ± 0.1 °C) in seawater with pH ranging between 7.90 and 8.45. Intra-shell boron isotopes showed large variability with an upper limit value of ≈30‰. Our results suggest that the fractionation factor α4-3 of 0.97352 ( Klochko et al., 2006) is in better agreement with our experiments and with direct pH measurements in seawater vacuoles associated with the biomineralization process in these foraminifera. Despite the large variability of the skeletal pH values in each cultured specimen, it is possible to link the lowest calculated pH values to the experimental culture pH values while the upper pH limit is slightly below 9. This variability can be interpreted as follows: foraminifera variably increase the pH at the biomineralization site to about 9. This increase above ambient seawater pH leads to a range in δ 11B (Δ 11B) for each seawater pH. This Δ 11B is linearly correlated with the culture seawater pH with a slope of -13.1 per pH unit, and is independent of the fractionation factor α4-3, or the δ 11B sw through time. It may also be independent of the p KB (the dissociation constant of boric acid) value. Therefore, Δ 11B in foraminifera can potentially reconstruct paleo-pH of seawater.

  5. Sr partitioning in the benthic foraminifera Ammonia aomoriensis and Amphistegina lessonii

    NARCIS (Netherlands)

    Langer, G.; Sadekov, A.; Thoms, S.; Keul, N.; Nehrke, G.; Mewes, A.; Greaves, M.; Misra, S.; Reichart, G.-J.; de Nooijer, L.J.; Bijma, J.; Elderfield, H.

    2016-01-01

    The shallow water benthic foraminifera Ammonia aomoriensis and Amphistegina lessonii were grown at different seawater Sr/Ca and the test Sr/Ca ratio was determined by Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry. A. aomoriensis test Sr/Ca is positively correlated with seawater

  6. Strangers in Paradise: The biogeographic range expansion of the foraminifera Amphistegina in the Mediterranean Sea

    Science.gov (United States)

    Langer, M. R.; Weinmann, A. E.; Rödder, D.; Lötters, S.

    2012-04-01

    Species distribution models (SDMs) have become important tools in biogeography and biodiversity research over the last decades. They are mainly based on the fundamental niche concept and allow the correlative prediction of species' potential distributional ranges by combining occurrence records with information on environmental (e.g. climatic) conditions. The generated environmental envelope of a species is projected into geographic space, thus defining areas of adequate habitat suitability. Here we apply a species distribution model (SDM) to assess potential range expansions of Amphistegina spp. in the Mediterranean Sea under current und future climate conditions. The model uses an environmental envelope of information from localities where amphisteginids are currently known to occur. Amphisteginid foraminifers are a group of circumtropically distributed, larger symbiont-bearing, calcareous foraminifera that have a well-documented record as detectors of historical climate change. They are currently expanding their biogeographic range in the Mediterranean Sea and rapidly progressing northwestward, closely approaching the Adriatic and the Tyrrhenian Sea. The shift in range locally leads to profound ecological changes where amphisteginids have become the dominant species along entire stretches of coastline. Mass deposits of amphisteginids reflect an increased carbonate production and reduced assemblage diversity, and these are likely to trigger major changes in ecosystem functioning. It is anticipated that the ongoing warming trend will convey the northwestward migration of amphisteginid foraminifers. Our model indicates that further warming is likely to cause a northwestward range extension and predicts dispersal through the straits of Sicily, Messina and Otranto into the Tyrrhenian and Adriatic Sea. Rapid proliferation and the extreme abundances of amphisteginid foraminifera affect the dynamic equilibrium of established foraminiferal biotas. In the eastern

  7. Extremely heat tolerant photosymbiosis in a shallow marine benthic foraminifera

    Science.gov (United States)

    Schmidt, Christiane; Danna, Titelboim; Janett, Brandt; Raphael, Morard; Barak, Herut; Sigal, Abramovich; Ahuva, Almogi-Labin; Michal, Kucera

    2016-04-01

    Thermal stress leads to the loss of algal symbionts (bleaching) in many shallow marine calcifiers including foraminifera. The bleaching threshold often occurs at water temperatures, which are likely to be exceeded in the near future due to global warming. Preadaptation represents one mechanism allowing photosymbiotic organisms to persist under warmer conditions, providing the tolerance can be carried to new habitats. Here we provide evidence for the existence of such adaptation in the benthic foraminifera Pararotalia calcariformata recently discovered in the eastern Mediterranean. We identify its symbionts as a consortium of diatom species dominated by Minutocellus polymorphus. We show that in the field, the foraminifera retains its pigments at a thermally polluted site, where peak water temperatures reach 36°C. To test whether this tolerance represents a widespread adaptation, we conducted manipulative experiments exposing populations from an unpolluted site to elevated temperatures for up to three weeks. The populations were kept in co-culture with the more thermally sensitive diatom-bearing foraminifera Amphistegina lobifera. Reduced photosynthetic activity in A. lobifera occurred at 32°C whereas photochemical stress in P. calcariformata was first observed during exposure to 36°C and chronic photoinhibition (but not mortality) first occurred at 42°C. Survivorship was high in all treatments, and growth was observed under thermal conditions similar to summer maxima at the thermally polluted site (35-36°C). The photosymbiosis in P. calcariformata is unusually thermally tolerant for a photosymbiont-bearing eukaryote. The thermal tolerance of this photosymbiosis is present in a natural environment where its thermal threshold is never realized. These observations imply that photosymbiosis in marine protists can respond to elevated temperatures by drawing on a pool of naturally occurring pre-adaptations. It also provides a perspective on the massive occurrence of

  8. Extremely heat tolerant photo-symbiosis in a shallow marine benthic foraminifera

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    Schmidt, C.; Titelboim, D.; Brandt, J.; Herut, B.; Abramovich, S.; Almogi-Labin, A.; Kucera, M.

    2016-08-01

    Bleaching, the loss of algal symbionts, occurs in marine photosymbiotic organisms at water temperatures minimally exceeding average summer SST (sea surface temperatures). Pre-adaptation allows organisms to persist under warmer conditions, providing the tolerance can be carried to new habitats. Here we provide evidence for the existence of such adaptation in the benthic foraminifera Pararotalia calcariformata. This species occurs at a thermally polluted site in the Mediterranean, where water temperatures reach a maxima daily average of 36 °C during the summer. To test whether this occurrence represents a widespread adaptation, we conducted manipulative experiments exposing this species from an unpolluted site to elevated temperatures (20–42 °C). It was kept in co-culture with the more thermally sensitive foraminifera Amphistegina lobifera in two experiments (20–36 °C). Reduced photosynthetic activity in A. lobifera occurred at 32 °C whereas photochemical stress in P. calcariformata was first observed during exposure to 36 °C. Pararotalia calcariformata survived all treatment conditions and grew under 36 °C. The photosymbiosis in P. calcariformata is unusually thermally tolerant. These observations imply that marine eukaryote-eukaryote photosymbiosis can respond to elevated temperatures by drawing on a pool of naturally occurring pre-adaptations. It also provides a perspective on the massive occurrence of symbiont-bearing foraminifera in the early Cenozoic hothouse climate.

  9. Invasive symbiont bearing (and other) foraminifera altering the community structure of eastern Mediterranean rocky reefs environments

    Science.gov (United States)

    Hyams-Kaphzan, Orit; Perelis Grossowicz, Lydia; Almogi-Labin, Ahuva

    2015-04-01

    The rocky reefs of the Israeli eastern Mediterranean shelf constitute a highly diverse marine ecosystem rich in macroalgae and calcareous organisms. The benthic foraminiferal community living in this ecosystem is rapidly changing due to massive invasion of symbiont bearing foraminifera (SBF) as well as other foraminiferal species of tropical origin. This trend facilitated by the ongoing increase in temperature enables more tropical species to adjust to the eastern Mediterranean habitats. In order to document the status of the benthic foraminiferal community structure rocky reefs at Akhziv (AK) and Carmel Head (CH), northern Israel were sampled by scuba diving. Different macroalgae species, including invasive ones, accommodating the live epiphytic benthic foraminifera were sampled twice a year at AK and in each season at CH in three depth intervals between 5-20 m, during 2013-4. The numerical abundance of the group ranges between 170-3500 #/10cc (wet macroalgae volume) without any significant difference in standing stocks within regions, water depths or macroalgae preference. In total 77 benthic foraminiferal species were identified 71 in CH and only 43 at AK. Species richness per site varied between 3 and 42 with higher values at CH. 25% of all species were aliens, mostly Lessepsian, that comprise on average 70% - 84% of the numerical abundance of AK and CH respectively. Cluster analysis using benthic foraminifera relative abundance data did not correlate with the different macroalgae species, water depths or seasonality, indicating that the foraminiferal community in the two regions is quite homogenous. Amphistegina lobifera a Lessepsian migrant is by far the most common species on the Israeli rocky reefs occurring in all samples and comprising 18-93% of the foraminiferal community. Heterostegina depressa behaves similarly to A. lobifera though it occurs in lower numbers. Pararotalia calcariformata, a recently arriving SBF occupies mainly shallow water sites at CH

  10. Intra-Shell boron isotope ratios in benthic foraminifera: Implications for paleo-pH reconstructions

    Science.gov (United States)

    Rollion-Bard, C.; Erez, J.

    2009-12-01

    The boron isotope composition of marine carbonates is considered to be a seawater pH proxy. Nevertheless, the use of δ11B has some limitations: 1) the knowledge of fractionation factor (α4-3) between the two boron dissolved species (boric acid and borate ion), 2) the δ11B of seawater may have varied with time and 3) the amplitude of the "vital effects" of this proxy. Using secondary ion mass spectrometry (SIMS), we looked at the internal variability in the boron isotope ratio of the shallow water, symbionts bearing foraminiferan Amphistegina lobifera. Specimens were cultured at constant temperature (24±0.1 °C) in seawater with pH ranging between 7.90 and 8.45. We performed 6 to 8 measurements of δ11B in each foraminifera. Intra-shell boron isotopes show large variability with an upper threshold value of pH ~ 9. The ranges of the skeletal calculated pH values in different cultured foraminifera, show strong correlation with the culture pH values and may thus serve as proxy for pH in the past ocean.

  11. Sr partitioning in the benthic foraminifera

    NARCIS (Netherlands)

    Langer, G.; Sadekov, A.; Thoms, S.; Keul, N.; Nehrke, G.; Mewes, A.; Greaves, M.; Misra, S.; Reichart, G.-J.; de Nooijer, L.J.; Bijma, J.; Elderfield, H.

    2016-01-01

    The shallow water benthic foraminifera Ammonia aomoriensis and Amphistegina lessonii were grown at differentseawater Sr/Ca and the test Sr/Ca ratio was determined by Laser Ablation - Inductively Coupled Plasma - MassSpectrometry. A. aomoriensis test Sr/Ca is positively correlated with seawater

  12. Climate-driven range extension of Amphistegina (protista, foraminiferida: models of current and predicted future ranges.

    Directory of Open Access Journals (Sweden)

    Martin R Langer

    Full Text Available Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa at 31°S. To project future species distributions, we applied a species distribution model (SDM based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year(-1, and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.

  13. Climate-driven range extension of Amphistegina (protista, foraminiferida): models of current and predicted future ranges.

    Science.gov (United States)

    Langer, Martin R; Weinmann, Anna E; Lötters, Stefan; Bernhard, Joan M; Rödder, Dennis

    2013-01-01

    Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa) at 31°S. To project future species distributions, we applied a species distribution model (SDM) based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year(-1), and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.

  14. Heading for new shores: projecting marine distribution ranges of selected larger foraminifera.

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    Anna E Weinmann

    Full Text Available The distribution of modern symbiont-bearing larger foraminifera is confined to tropical and subtropical shallow water marine habitats and a narrow range of environmental variables (e.g. temperature. Most of today's taxa are restricted to tropical and subtropical regions (between 30°N and 30°S and their minimum temperature limits are governed by the 14 to 20°C isotherms. However, during times of extensive global warming (e.g., the Eocene and Miocene, larger foraminifera have been found as far north as 50°N (North America and Central Europe as well as towards 47°S in New Zealand. During the last century, sea surface temperatures have been rising significantly. This trend is expected to continue and climate change scenarios for 2050 suggest a further increase by 1 to 3°C. We applied Species Distribution Models to assess potential distribution range changes of three taxa of larger foraminifera under current and future climate. The studied foraminifera include Archaias angulatus, Calcarina spp., and Amphistegina spp., and represent taxa with regional, superregional and global distribution patterns. Under present environmental conditions, Amphistegina spp. shows the largest potential distribution, apparently due to its temperature tolerance. Both Archaias angulatus and Calcarina spp. display potential distributions that cover currently uninhabited regions. Under climate conditions expected for the year 2050, all taxa should display latitudinal range expansions between 1 to 2.5 degrees both north- and southward. The modeled range projections suggest that some larger foraminifera may colonize biogeographic regions that so far seemed unsuitable. Archaias angulatus and Calcarina spp. also show an increase in habitat suitability within their native occurrence ranges, suggesting that their tolerance for maximum temperatures has yet not been fully exploited and that they benefit from ocean warming. Our findings suggest an increased role of larger

  15. Heading for new shores: projecting marine distribution ranges of selected larger foraminifera.

    Science.gov (United States)

    Weinmann, Anna E; Rödder, Dennis; Lötters, Stefan; Langer, Martin R

    2013-01-01

    The distribution of modern symbiont-bearing larger foraminifera is confined to tropical and subtropical shallow water marine habitats and a narrow range of environmental variables (e.g. temperature). Most of today's taxa are restricted to tropical and subtropical regions (between 30°N and 30°S) and their minimum temperature limits are governed by the 14 to 20°C isotherms. However, during times of extensive global warming (e.g., the Eocene and Miocene), larger foraminifera have been found as far north as 50°N (North America and Central Europe) as well as towards 47°S in New Zealand. During the last century, sea surface temperatures have been rising significantly. This trend is expected to continue and climate change scenarios for 2050 suggest a further increase by 1 to 3°C. We applied Species Distribution Models to assess potential distribution range changes of three taxa of larger foraminifera under current and future climate. The studied foraminifera include Archaias angulatus, Calcarina spp., and Amphistegina spp., and represent taxa with regional, superregional and global distribution patterns. Under present environmental conditions, Amphistegina spp. shows the largest potential distribution, apparently due to its temperature tolerance. Both Archaias angulatus and Calcarina spp. display potential distributions that cover currently uninhabited regions. Under climate conditions expected for the year 2050, all taxa should display latitudinal range expansions between 1 to 2.5 degrees both north- and southward. The modeled range projections suggest that some larger foraminifera may colonize biogeographic regions that so far seemed unsuitable. Archaias angulatus and Calcarina spp. also show an increase in habitat suitability within their native occurrence ranges, suggesting that their tolerance for maximum temperatures has yet not been fully exploited and that they benefit from ocean warming. Our findings suggest an increased role of larger foraminifera as

  16. Combined effects of sea water acidification and copper exposure on the symbiont-bearing foraminifer Amphistegina gibbosa

    Science.gov (United States)

    Marques, Joseane Aparecida; de Barros Marangoni, Laura Fernandes; Bianchini, Adalto

    2017-06-01

    Coral reefs are threatened by global and local stressors such as ocean acidification and trace metal contamination. Reliable early warning monitoring tools are needed to assess and monitor coral reef health. Symbiont-bearing foraminifers ( Amphistegina gibbosa) were kept under ambient conditions (no sea water acidification and no copper addition) or exposed to combinations of different levels of sea water pH (8.1, 7.8, 7.5 and 7.2) and environmentally relevant concentrations of dissolved copper (measured: 1.0, 1.6, 2.3 and 3.2 µg L-1) in a mesocosm system. After 10- and 25-d exposure, foraminifers were analyzed for holobiont Ca2+-ATPase activity, bleaching, growth and mortality. Enzyme activity was inhibited in foraminifers exposed to pH 7.2 and 3.2 µg L-1 Cu for 25 d. Bleaching frequency was also higher at pH 7.2 combined with copper addition. There was no significant effect of sea water acidification and copper addition on mortality. However, test size was smaller in foraminifers exposed to copper, with a positive interactive effect of sea water acidification. These findings can be explained by the higher availability of free copper ions at lower water pH. This condition would increase Cu competition with Ca2+ for the binding sites on the organism, thus inhibiting Ca2+-ATPase activity and affecting the organism's overall fitness. Findings reported here suggest that key processes in A. gibbosa, such as calcification and photosynthesis, are affected by the combined effect of global (sea water acidification) and local (copper contamination) stressors. Considering the experimental conditions employed (mesocosm system, possible ocean acidification scenarios, low copper concentrations, biomarkers of ecological relevance and chronic exposure), our findings support the use of foraminifera and biomarkers analyzed in the present study as reliable tools to detect and monitor the ecological impacts of multiple stressors in coral reef environments.

  17. Invertebrate shells (mollusca, foraminifera) as pollution indicators, Red Sea Coast, Egypt

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    Youssef, Mohamed; Madkour, Hashem; Mansour, Abbas; Alharbi, Wedad; El-Taher, Atef

    2017-09-01

    To assess the degree of pollution and its impact on the environment along the Red Sea Coast, the most abundant nine species of recent benthic foraminifera and three species of molluscan shells have been selected for the analysis of Fe, Mn, Zn, Cu, Pb, Ni, Co, and Cd concentrations. The selected foraminiferal species are: Textularia agglutinans, Amphispsorus hemprichii, Sorites marginalis, Peneroplis planatus, Borelis schlumbergeri, Amphistegina lessonii, Ammonia beccarii, Operculina gaimairdi, and Operculinella cumingii. The selected molluscan shells are: Lambis truncata and Strombus tricornis (gastropods) and Tridacana gigas (bivalves). The inorganic material analysis of foraminifera and molluscs from the Quseir and Safaga harbors indicates that foraminifera tests include higher concentrations of heavy metals such as Fe and Mn than molluscan shells. These results are supported by the black tests of porcelaneous foraminifera and reflect iron selectivity. The Cd and Pb concentrations in molluscan shells are high in the El Esh Area because of oil pollution at this site. The Cu, Zn, and Ni concentrations in the studied invertebrates are high at Quseir Harbor and in the El Esh Area because of the strong influence of terrigenous materials that are rich in these metals. The heavy metal contamination is mostly attributed to anthropogenic sources.

  18. Anthropogenic perturbation of coral reef environments near Natal, Brazil: Clues from symbiont-bearing benthic foraminifera

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    Eichler, P.; Vital, H.; Sen Gupta, B. K.

    2014-12-01

    Besides global stressors such as temperature rise and acidification, local anthropogenic disturbances, especially those connected with tourism, affect many Atlantic patch reefs off the Brazilian shore. Using reef-inhabiting foraminifera with algal symbionts as environmental indicators, we confirmed this problem in coastal reefs near Natal, Rio Grande do Norte. The foraminiferal community is particularly depauperate in the small reefs of Pirangi, about 25 km south of Natal (~6o S, water depth tourism. However, living Amphistegina is still rare, and the only living Amphisorus is found in seagrass habitats. In contrast, many symbiont-bearing taxa, including peneroplids (virtually absent in Pirangi and Maracajaú) exist in sizeable populations northwest of Maracajaú, in the small patch reefs of the drowned Açu river valley (~4o 50' S).

  19. Biomineralization in perforate foraminifera

    NARCIS (Netherlands)

    de Nooijer, L.J.; Spero, H.J.; Erez, J.; Bijma, J.; Reichart, G.J.

    2014-01-01

    In this paper, we review the current understanding of biomineralization in perforate foraminifera. Ideas on the mechanisms responsible for the flux of Ca2 + and inorganic carbon from seawater into the test were originally based on light and electron microscopic observations of calcifying

  20. Paleoecology and biostratigraphic data of the large benthic foraminifera in the Oligocene-Miocene Qom Formation in Kahak area, in the Urumieh-Dokhtar province in Iran

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    mahnaz amirshahkarami

    2016-08-01

    Full Text Available The Oligocene-Miocene Qom Formation was deposited in different thickness in the Central Iran, Urumiehh–Dokhtar magmatic arc and Sanandaj–Sirjan provinces in Iran. The Oligocene-Miocene Kahak section of the Qom Formation in the Urumiehh–Dokhtar magmatic arc has been studied, in order to biostratigraphic data of the large benthic foraminifera. In the Kahak section, the foraminifera assemblages of the Qom Formation consist of Nummulites fichteli, Nummulites vascus, Eulepidina dilitata, Nephrolepidina sp., Neprolepidina tournoueri, Eulepidina sp., Pseudolituonella reicheli, Miogypsina sp., Miogypsina irregularis, Amphistegina sp., Operculina sp., Bozorginella qumiensis, Triloculina trigonula, Triloculina tricarinata, Peneroplis sp., Peneroplis thomasi, Dendritina ranji, Triloculina trigonula, Rotalia sp., Pyrgo sp., Elphidium sp., Borelis melo and Borelis curdica.  In the Kahak section of the Qom Formation, four assemblage biozones of the large benthic foraminifera have been recognized from Rupelian, Chattian, Aquitanian and Burdigalian stages. These biozones are similar to assemblage biozones of the Oligocene-Miocene Asmari Formation in the Zagros Basin in southwest of Iran. Distribution type of the Oligocene-Miocene foraminifera in the Kahak depositions of the Qom Formation indicates to depositional settings of the  lagoon, open lagoon and shallow open marine paleoenvironments. There is some similarity of foraminifera assemblage in Qom Formation sediments with other locality of Tethys including Mediterranean and Indo-West Pacific.

  1. Barium in planktonic foraminifera

    Energy Technology Data Exchange (ETDEWEB)

    Lea, D.W.; Boyle, E.A. (Massachusetts Inst. of Tech., Cambridge (United States))

    1991-11-01

    Reconstructions of Ba distributions in ancient oceanic surface waters could provide new insight into paleoceanographic change. Calcite shells of planktonic foraminifera potentially provide a means of reconstructing such paleo-Ba distributions if lattice-bound Ba can be determined on shells recovered from deep-sea cores. Planktonic foraminifera shells from a series of cores were purified of non-lattice-bound Ba associated with organic or sedimentary phases by a combination of physical agitation, oxidative-reductive steps, acid leaches, and a novel alkaline-DTPA step to dissolve barite. A sequential dissolution of a large sample of cleaned shells of the planktonic foraminifer Globigerinoides conglobatus indicates homogeneous distribution of Ba in the shell material. Comparison of shells from sediments, sediment traps, and plankton tows indicates no significant differences in the Ba content of the purified shells. Variation in foraminiferal Ba contents between the Pacific, Atlantic, and Mediterranean Sea is consistent with the trend in surface seawater Ba. The calculated distribution coefficient for Ba incorporation in five species based on these data is 0.19 {plus minus} 0.05. Several species of the non-spinose planktonic foraminifera Globorotalia have Ba/Ca ratios ranging from 2 to 13 {mu}mol; these high Ba contents might be explained by differences in the way these foraminifera precipitate their shells. A temporal record of Ba/Ca in samples of Globigerinoides and Orbulina from a core in the northwest Atlantic suggests that the Ba concentration of surface waters at this site has not changed by more than 20% over the last 14 kyr.

  2. Biomineralization in foraminifera

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    Nooijer, L. D.; Toyofuku, T.; Bijma, J.; Reichart, G. J.

    2015-12-01

    Foraminifera are popular tools in paleoceanography since incorporation of minor/ major elements and fractionation of stable isotopes into their carbonate shells depend on environmental conditions (e.g. temperature, salinity, pH). Their shell chemistry is markedly different from that of inorganically precipitated CaCO3, reflecting that calcification is a process under strong biological control. The cellular components responsible for calcification are only partly identified in foraminifera and include the involvement of organic templates, trans-membrane ion transporters and selective ion removal. Recent results suggest that transmembrane exchange of H+ for Ca2+ is directly responsible for calcification. The resulting high pH inside and lowered pH outside the foraminifer results in an efficient CO2 'trap' after which carbon dioxide is converted to carbonate prior to calcification. Amongst others, this explains how some foraminifera are able to calcify in undersaturated seawater and may explain their moderate response to ocean acidification. Minor and trace metals incorporated into test carbonate reflect the processes involved in biomineralization and can thus be used to unravel the different factors and processes involved. Still, a more detailed understanding of the processes involved in foraminiferal calcification is needed to explain observed (inter-species) differences in partition coefficients for the incorporation of minor and trace metals and isotopic fractionation.

  3. Li isotopes in foraminifera: a new proxy for past ocean dissolved inorganic carbon

    Science.gov (United States)

    Vigier, N.; Rollion-Bard, C.; Erez, J.

    2009-12-01

    Past ocean pH and pCO2 are critical parameters for establishing relationships between Earth climate and carbon cycle. For the Miocene-Pleistocene period, two main proxies have been used: carbon isotopes of di-unsaturated alkenones extracted from sea cores, and boron isotope signatures of marine carbonates [1, 2]. Both techniques lead to selfconsistent palaeooceanic pH or pCO2 estimates, but are associated with large uncertainties. Moreover, the paleovariations calculated from boron isotope measurements are a matter of debate. Additional proxies are therefore needed. Based on an in-situ analytical technique recently developed [3], we analysed a series of foraminifera - Amphistegina - cultured under various conditions (in pH, T and Dissolved Inorganic Carbon). We show that the lithium isotope signature of the foraminifera correlates with the DIC (r2 = 0.93). Conversely, there is no dependency of Li isotope signature on pH or T. A simple model of biomineralization in which growth rate is a key parameter can fit the whole dataset, including published values for other foraminifera species [4, 5]. This strongly suggests that the DIC-δ7Li correlation highlighted by the cultured Amphistegina can also be applied to other species. These results, combined with the published oceanic Li and B isotope paleovariations [2, 4, 5], allow us to estimate the ocean DIC and pCO2 evolution for the past 18Ma. The similarity with the pCO2 curve given by carbon isotopes measured in di-unsaturated alkenones is striking. This supports the use of Li isotopes as a new proxy and adds support to the existing data. It also suggests, in contrast with the common view, a less significant role of river input on the variation of the ocean Li isotope composition, at least for the period considered. [1] Pagani et al. (2005) Science 309, 600-603. [2] Pearson & Palmer (2000) Nature 406, 695-699. [3] Vigier et al. (2007) G-cubed 8, Q01003 [4] Hall et al. (2005) Mar. Geology 217, 255-265 [5] Hathorne

  4. Foraminifera in Cenozoic Paleoenvironments

    Institute of Scientific and Technical Information of China (English)

    Brian McGowran

    2005-01-01

    Paleontologists search the fossil record for evidence of age, ancient environments, phylogenetic reconstructions and ancient communities. Cenozoic foraminifera preserve evidence for all of these simultaneously from the water column and from at, above and below the sediment/water interface. As our understanding of foraminiferal assemblages and their place in the strata (biofacies) becomes more sophisticated, so are foraminiferal biofacies challenged to contribute to more subtle problems in Cenozoic earth and life history. Progress is described as a series of five "integrations". (Ⅰ) The quantification of foraminiferal biofacies was an advance on simple presences and absences of species meeting such questions as marine or nonmarine, or shallow or deep. (Ⅱ) Foraminiferal shells carry geochemical signals especially isotopes of oxygen (temperature, ice volume), carbon (nutrition and the carbon cycle), and strontium (seawater ratios through time). (Ⅲ) From modern foraminiferal biology we have lifestyle insights leading to a model of oceans and paleo-oceans called the trophic resource continuum, a valuable way into greenhouse-icehouse comparisons and contrasts. (Ⅳ) Biofacies changes in space and time are sometimes abrupt with little evidence of diachrony, and sometimes gradual. These patterns are clarified in the context of sequence stratigraphy (which they enrich in turn). (Ⅴ) The paleobiological counterpart of sequence stratigraphy is evolutionary paleoecology, reconstructing communities in deep time. The foraminifera are perfectly suited to investigate the possibility (or likelihood) that global environmental shifts have controlled community turnover in the pelagic, neritic and terrestrial realms.

  5. Molecular biological research on Foraminifera

    Institute of Scientific and Technical Information of China (English)

    LI Baohua; Kemal Topac ERTAN; Christoph HEMLEBEN

    2005-01-01

    As one of the most important groups in micropaleontology, Foraminifera is traditionally described to have a membranous, agglutinated or carbonate shell according to its morphology, which resembles the marine granuloreticuloseans. However, recent molecular analyses on its ribosomal RNA gene have disclosed the existence of the naked, and also freshwater and terrestrial species.Foraminiferal SSU rDNA sequence suggests that this group is positioned at the base of the Eukaryotes phylogenetic trees, between Euglenoida and Diplomonadida. Existence of a large amount of genetic types in planktonic foraminifera suggests an underestimation of the biodiversity for the nearly 50 species in world oceans and their close relationship with the ocean environment, such as bio-geographic distribution and water currents. This provides a more reliable proxy for future paleoenvironmental study.

  6. Spatial Patterns in the Distribution, Diversity and Abundance of Benthic Foraminifera around Moorea (Society Archipelago, French Polynesia.

    Directory of Open Access Journals (Sweden)

    Olugbenga T Fajemila

    Full Text Available Coral reefs are now subject to global threats and influences from numerous anthropogenic sources. Foraminifera, a group of unicellular shelled organisms, are excellent indicators of water quality and reef health. Thus we studied a set of samples taken in 1992 to provide a foraminiferal baseline for future studies of environmental change. Our study provides the first island-wide analysis of shallow benthic foraminifera from around Moorea (Society Archipelago. We analyzed the composition, species richness, patterns of distribution and abundance of unstained foraminiferal assemblages from bays, fringing reefs, nearshore and back- and fore-reef environments. A total of 380 taxa of foraminifera were recorded, a number that almost doubles previous species counts. Spatial patterns of foraminiferal assemblages are characterized by numerical abundances of individual taxa, cluster groups and gradients of species richness, as documented by cluster, Fisher α, ternary plot and Principal Component Analyses (PCA. The inner bay inlets are dominated by stress-tolerant, mostly thin-shelled taxa of Bolivina, Bolivinella, Nonionoides, Elongobula, and Ammonia preferring low-oxygen and/or nutrient-rich habitats influenced by coastal factors such as fresh-water runoff and overhanging mangroves. The larger symbiont-bearing foraminifera (Borelis, Amphistegina, Heterostegina, Peneroplis generally live in the oligotrophic, well-lit back- and fore-reef environments. Amphisteginids and peneroplids were among the few taxa found in the bay environments, probably due to their preferences for phytal substrates and tolerance to moderate levels of eutrophication. The fringing reef environments along the outer bay are characterized by Borelis schlumbergeri, Heterostegina depressa, Textularia spp. and various miliolids which represent a hotspot of diversity within the complex reef-lagoon system of Moorea. The high foraminiferal Fisher α and species richness diversity in outer bay

  7. Bathymetric zonation of modern shelf benthic foraminifera in the Levantine Basin, eastern Mediterranean Sea

    Science.gov (United States)

    Avnaim-Katav, Simona; Hyams-Kaphzan, Orit; Milker, Yvonne; Almogi-Labin, Ahuva

    2015-05-01

    Siliciclastic carbonate-poor sediments are common in southern and central parts of the inner Israeli shelf, part of the Nile littoral cell and in deeper water along the entire coast, while carbonate rich sediments occur in northern Israel and in submerged rocky environments. The distribution of benthic foraminifera, common components of these environments, was studied in surface sediment samples in order to identify their bathymetric zonation using multivariate statistical analyses. The dead foraminiferal assemblages exhibit a clear bathymetric zonation directly related to substrate type. A distinct faunal change has been found at approximately 40 m water depth coinciding with the shift from the shallow-water sand belt, distributed parallel to the Israeli coast up to Haifa Bay, to a silty-clayey belt relatively rich with organic matter extending westward along the entire SE Mediterranean shelf. Ammonia parkinsoniana, Ammonia sp. 1, Buccella granulata, Nubeculina divaricata and Adelosina sp. 1 predominating the shallow-water depths are positively related to sand content and negatively related to water depth. Other species, such as Asterigerinata mamilla, Hanzawaia rhodiensis, Reussella spinulosa, Triloculina marioni and Valvulineria bradyana, occurring between 40 and 100 m, exhibit a positive relationship with total organic carbon content and water depth. Beyond the Nile littoral cell and partly in its distal part Amphistegina lessonii, Peneroplis pertusus, Pseudoschlumbergerina ovata, Pseudoschlumbergerina sp. 1 and Quinqueloculina ungeriana dominate the rocky and coarse sand substrate, exhibiting a more positive relationship with higher carbonate content values. The distinct bathymetric zonation established in this study may prove to be useful in fossil records for accurate paleo-bathymetry reconstruction of Quaternary records in this dynamic system prone to frequent sea level fluctuations.

  8. Interpreting the role of pH on stable isotopes in large benthic foraminifera

    Science.gov (United States)

    Robbins, Lisa L.; Knorr, P.O.; Wynn, J.G.; Hallock, P.; Harries, P.

    2016-01-01

    Large benthic foraminifera (LBF) are prolific producers of calcium carbonate sediments in shallow, tropical environments that are being influenced by ocean acidification (OA). Two LBF species, Amphistegina gibbosa (Order Rotaliida) with low-Mg calcite tests and Archaias angulatus (Order Miliolida) with high-Mg calcite tests, were studied to assess the effects of pH 7.6 on oxygen and carbon isotopic fractionation between test calcite and ambient seawater. The δ18O and δ13C values of terminal chambers and of whole adult tests of both species after 6 weeks were not significantly different between pH treatments of 8.0 and 7.6. However, tests of juveniles produced during the 6-week treatments showed significant differences between δ18O and δ13C values from control (pH 8.0) when compared with the treatment (pH 7.6) for both species. Although each individual's growth was photographed and measured, difficulty in distinguishing and manually extracting newly precipitated calcite from adult specimens likely confounded any differences in isotopic signals. However, juvenile specimens that resulted from asexual reproduction that occurred during the experiments did not contain old carbonate that could confound the new isotopic signals. These data reveal a potential bias in the design of OA experiments if only adults are used to investigate changes in test chemistries. Furthermore, the results reaffirm that different calcification mechanisms in these two foraminiferal orders control the fractionation of stable isotopes in the tests and will reflect decreasing pH in seawater somewhat differently. .

  9. Foraminifera and changing pattern of monsoon rainfall

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    The palaeomonsoonal history can be reconstructed utilizing climatically sensitive properties of marine microorganisms; foraminifera. The results show a major boundary at 3500 years B.P. and periods of rather low precipitation approximately at 420...

  10. Long term cultivation of larger benthic Foraminifera

    Science.gov (United States)

    Wöger, Julia; Eder, Wolfgang; Kinoshita, Shunichi; Antonino, Briguglio; Carles, Ferrandes-Cañadell; Hohenegger, Johann

    2015-04-01

    Benthic Foraminifera are used in a variety of applications employing numerous different methods, i.e. ecological monitoring, studying the effects of ocean acidification, reconstructing palaeo-bathymetry or investigating palaeo-salinity and palaeo-temperature to name only a few. To refine our understanding of ecological influences on larger benthic foraminiferal biology and to review inferences from field observations, culture experiments have become an indispensable tool. While culture experiments on smaller benthic foraminifera have become increasingly frequent in the past century, reports of the cultivation of symbiont bearing larger Foraminifera are rare. Generally, cultivation experiments can be divided into two groups: Culturing of populations and cultivation of single specimens allowing individual investigation. The latter differ form the former by several restrictions resulting from the need to limit individual motility without abridging microenvironmental conditions in the Foraminiferans artificial habitat, necessary to enable the individual to development as unfettered as possible. In this study we present first experiences and preliminary results of the long-term cultivation of larger benthic Foraminifera conducted at the 'Tropical Biosphere Research Station Sesoko Island, University of the Ryukyus', Japan, trying to reproduce natural conditions as closely as possible. Individuals of three species of larger benthic Foraminifera (Heterostegina depressa, Palaeonummulites venosus and Operculina complanata) have been cultured since April 2014. At the time of the general assembly the cultivation experiments will have been going on for more than one year, with the aim to investigate growth rates, longevities and reproduction strategies for comparison with results statistically inferred from application of the of the 'natural laboratory' method. The most important factor influencing foraminiferal health and development was found to be light intensity and light

  11. Larger foraminifera from Central Falcon (Venezuela)

    NARCIS (Netherlands)

    Gorter, Nettie E.; Vlerk, van der I.M.

    1931-01-01

    Dr. H. G. Kugler, chief geologist of the North Venezuelan Petroleum Company, at Puerto Cabello, entrusted us with the examination of a collection of larger foraminifera, selected from material collected by the geologists of this Company in Central Falcon. Dr. A. Senn kindly added material that had a

  12. Role of foraminifera in oceanographic events

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    in foraminifera is a tendency to deviate from the normal form which may lead to erection of species into subspecies. Recent trends in taxonomic classification are based on the wall structure, surface ultrastructures and amino acid compositions of Recent and fossil...

  13. Distribution of foraminifera in the Cochin estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Balasubramanian, T.

    at the study site has been undertaken. From foraminiferal data of the last two decades, it is concluded, based on total number of species present that it seems probable there are no adverse effects on the organisms, especially Foraminifera due to deepening...

  14. Tolerance of benthic foraminifera (Protista : Sarcodina) to hydrogen sulphide

    NARCIS (Netherlands)

    Moodley, L.; Schaub, B.; Van der Zwaan, G.J.; Herman, P.M.J.

    1998-01-01

    Benthic foraminifera are dominant members of tb meiofauna, commonly occurring below the anoxic-oxic interface in marine sediments. The absence of oxygen in marine coastal sediments is often correlated with the formation of hydrogen sulphide. In this study the tolerance of benthic foraminifera (from

  15. Tolerance of benthic foraminifera (Protista : Sarcodina) to hydrogen sulphide

    NARCIS (Netherlands)

    Moodley, L.; Schaub, B.; Van der Zwaan, G.J.; Herman, P.M.J.

    1998-01-01

    Benthic foraminifera are dominant members of tb meiofauna, commonly occurring below the anoxic-oxic interface in marine sediments. The absence of oxygen in marine coastal sediments is often correlated with the formation of hydrogen sulphide. In this study the tolerance of benthic foraminifera (from

  16. Monitoring oil spill bioremediation using marsh foraminifera as indicators.

    Science.gov (United States)

    Sabean, J A R; Scott, D B; Lee, K; Venosa, A D

    2009-01-01

    A controlled experiment was conducted in June 2000 to identify the environmental impacts of weathered crude oil on an Atlantic coastal salt marsh to help evaluate in situ biological remediation techniques for restoring the environment. Foraminifera, marsh microfossils known to be sensitive to a range of environmental stress factors, were used to monitor the effects of the residual oil and the experimental treatments. Results show that the foraminifera responded quickly to the oil and that the oil had a statistically significant, negative impact, as demonstrated by a dramatic increase in deformities in the tests of Miliammina fusca, compared to specimens from the non-oiled control plots. The results clearly show that foraminifera can be excellent indicators of oil pollution using only the percent of deformed tests. The advantages that foraminifera provide are the ease of sampling, processing and examination, with the added benefit that these organisms leave a fossil record.

  17. Holocene benthonic foraminifera from the shelf sediments of Kerala coast

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Of the 32 species of benthic foraminifera recovered here some show definite Indo-Pacific affinity. Ecological parameters which govern this offshore region are considered. Several species show similarities with those found in the Neogene while...

  18. Planktonic foraminifera from core tops of western equatorial Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Guptha, M.V.S.

    A set of seven core tops from western equatorial Indian ocean were analysed for planktonic foraminifera, which has yielded 20 planktonic foraminiferal species. Among them Globorotalia menardii, Globigerinoides sacculifer and G. ruber constitute...

  19. Living planktonic foraminifera of the Wadge bank, Northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Panikkar, B.M.; Kutty, M.K.

    Twenty three species of living planktonic Foraminifera belonging to 11 genera have been studied from the Wadge Bank area off southern tip of the Indian peninsula. The fauna is characterized by species such as Globigerinoides conglobatus, G...

  20. Some observations on the Miocene foraminifera from Kachchh, Western India

    Digital Repository Service at National Institute of Oceanography (India)

    Jauhri, A.K.; Khare, N.

    in the absence of planktonic species. However, these species as well as other associated index forms need to be studied in different sections of Kachchh for their true stratigraphic ranges. The existing knowledge on the specific composition of foraminifera...

  1. Counts of Foraminifera from Selected North Atlantic Cores, LDEO

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Counts of primarily planktonic foraminifera from Dr. W.F. Ruddiman and staff at the Lamont-Doherty Earth Observatory of Columbia University are included in these...

  2. Intertidal foraminifera from Miramar-Caranzalem Shoreline, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Birajdar, S.M.; Nigam, R.

    Quantitative analysis of foraminifera (entire and broken) revealed that Rotalina, composed of 29 species, constituted 95.18% while Miliolina, composed of 11 species, and Textulariina, with 5 species were poorly represented. Temperature, salinity...

  3. Recent planktonic foraminifera from the sediment off Karwar and Mangalore

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Guptha, M.V.S.

    of planktonic foraminifera from the shore towards the slope, indicative of a regulated sediment discharge and rate of sedimentation in the area. All the species represented are typical warm-water fauna, with one exception. Undoubted, though rare, @i...

  4. The importance of large benthic foraminifera to reef island sediment budget and dynamics at Raine Island, northern Great Barrier Reef

    Science.gov (United States)

    Dawson, John L.; Smithers, Scott G.; Hua, Quan

    2014-10-01

    Low-lying reef islands are among the most vulnerable environments on earth to anthropogenic-induced climate change and sea-level rise over the next century because they are low, composed of unconsolidated sediment that is able to be mobilised by waves and currents, and depend on sediments supplied by reef organisms that are particularly sensitive to environmental changes (e.g. ocean temperatures and chemistry). Therefore, the spatial and temporal links between active carbonate production and island formation and dynamics are fundamental to predicting future island resilience, yet remain poorly quantified. In this paper we present results of a detailed geomorphological and sedimentological study of a reef and sand cay on the northern Great Barrier Reef. We provide an empirical investigation of the temporal linkages between sediment production and reef island development using a large collection of single grain AMS 14C dates. Large benthic foraminifera (LBF) are the single most important contributor to contemporary island sand mass (47%; ranging from 36% to 63%) at Raine Island, reflecting rapid rates of sediment production and delivery. Standing stock data reveal extremely high production rates on the reef (1.8 kg m- 2 yr- 1), while AMS 14C dates of single LBF tests indicate rapid rates of sediment transferral across the reef. We also demonstrate that age is statistically related to preservation and taphonomic grade (severely abraded tests > moderately abraded tests > pristine tests). We construct a contemporary reef and island sediment budget model for Raine Island that shows that LBF (Baculogypsina, Marginopora and Amphistegina) contribute 55% of the sediment produced on the reef annually, of which a large proportion (54%) contribute to the net annual accretion of the island. The tight temporal coupling between LBF growth and island sediment supply combined with the sensitivity of LBF to bleaching and ocean acidification suggests that islands dominated by LBF are

  5. Secondary calcification of planktic foraminifera from the Indian sector of Southern ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Mohan, R.; Shetye, S.; Tiwari, M.; AnilKumar, N

    is controlled by temperature, salinity, light, nutrients and phytoplankton biomass. There is also a lateral southern extent in abundance of planktic foraminifera from surface sediments to plankton tows. The shell weights of the planktic foraminifera N...

  6. Benthic foraminifera as proxy for oxygen-depleted conditions off the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Mazumder, A.; Henriques, P.J.; Saraswat, R.

    In order to study the response of benthic foraminifera, especially the rectilinear bi- and tri-serial benthic foraminifera (RBF) to oxygen-depleted conditions from the Arabian Sea off central west coast of India, 103 surface sediment samples...

  7. No Latitudinal Trends in Body Size of Foraminifera

    Science.gov (United States)

    Liao, Z.; Payne, J.; Seixas, G.

    2012-12-01

    Many organisms, such as penguins and polar bears, follow Bergmann's rule, which states that body size of animals tends to increase as temperature decreases, and thus as latitude increases toward to poles. A study of marine mollusk bivalves across a latitudinal gradient found no correlation between body size and latitude along the North American Pacific Coast, suggesting that the body size of marine bivalves might be controlled by other factors. This posed the question: Is there a lack of correlation between latitude and body size for all marine invertebrates or is it unique to marine bivalves? In this study, we examined four suborders of benthic foraminifera, Lagenina, Miliolina, Rotaliina, and Textulariina, a diverse phylum of amoeboid protists, to determine the relationship between body size and latitude within and across suborders at the global scale. We measured the shell (test) dimensions of foraminifera from a compilation of monograph images of type specimens. The mean test size as well as the maximum body size of those foraminifera suborders does not vary with increasing latitude. Our results show that foraminifera do not follow Bergmann's rule, consistent with the body size distribution pattern observed in marine bivalves. Different biological and environmental factors that vary between foraminifera suborders, such as life habitats, behaviors, and physiology, might have a greater influence on body size distributions.

  8. Ecologic Atlas of Benthic Foraminifera of the Gulf of Mexico

    Science.gov (United States)

    Tietjen, John H.

    Because of their importance as indicators of petroleum deposits, the benthic foraminifera of the Gulf of Mexico are one of the most intensely studied groups of animals in the world. This is especially true of the foraminifera inhabiting the shallow shelf region of the northern and eastern Gulf; much less is known about the animals of the southern shelf, continental slope, and abyssal plains. The author spent 10 years examining collections from various not well-known areas of the Gulf; this atlas is a synthesis of distributional data from approximately 4500 previously known stations, plus new information from 400 additional stations.

  9. Zoological exploration of the continental shelf of Surinam: The foraminifera of the shelf of Surinam and the Guyanas

    NARCIS (Netherlands)

    Hofker, J.

    1983-01-01

    INDEX Introduction.................................................................................................................................... P. 5 List of samples studied for Foraminifera .................................................................................... P. 7 Alphabetic

  10. Effect of ocean acidification on the benthic foraminifera

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Bijma, J.

    2013-01-01

    About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA). Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic

  11. Effect of ocean acidification on the benthic foraminifera

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Bijma, J.

    2013-01-01

    About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA). Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic cal

  12. Frequency distribution of foraminifera off Trivandrum, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Kutty, M.K.; Panikkar, B.M.

    Fifty two species belonging to 31 genera of recent foraminifera have been identified from sediment samples collected from the inshore waters. Based on relative abundance of species, it is observed that along the coast, the nearshore region up to 5 m...

  13. Effect of ocean acidification on the benthic foraminifera

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Bijma, J.

    2013-01-01

    About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA). Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic cal

  14. Living benthic foraminifera as an environmental proxy in coastal ecosystems: A case study from the Aegean Sea (Greece, NE Mediterranean)

    Science.gov (United States)

    Koukousioura, Olga; Dimiza, Margarita D.; Triantaphyllou, Maria V.; Hallock, Pamela

    2011-12-01

    The species composition of the epiphytic benthic foraminiferal fauna was compared at two coastal locations in the Aegean Sea. Samples were collected during August 2001 and July 2003 along the southeastern coast of Andros Island at Korthi Gulf, where there are minimal anthropogenic activities, and at Kastro Gulf, with substantial anthropogenic influence. This study represents the first application of the FORAM Index (FI), which is a single-metric index for water quality originally developed for western Atlantic reef foraminiferal assemblages, to Mediterranean assemblages. Multivariate analyses distinguished three clusters of sample sites representing three foraminiferal assemblages. Samples dominated by the mixotrophic species, A. lobifera, were collected primarily from sites along the northern coasts of both gulfs. Characteristics of this assemblage, including relatively high dominance (D = 0.27-0.51), lower Shannon-Wiener diversity (H' = 1.3-2.1) and high FI (6.6-8.2), all reflect oligotrophic environmental conditions typical of pristine waters of the Aegean Sea. A. lobifera was typically the most common species in the second assemblage, though relative abundances of heterotrophic taxa were higher, resulting in somewhat higher diversity (H' = 1.6-2.4) and lower dominance (D = 0.14-0.36). These indices, as well as the FI range of 3.5-7.0 indicated somewhat more prevalent organic carbon resources but still relatively high water quality. This assemblage was found along the southern coast of Korthi Gulf and at more interior sites in northern Kastro Gulf. The third assemblage was dominated by smaller heterotrophic species, including notable proportions of the stress-tolerant taxa Ammonia spp. and Elphidium spp., and had few or no A. lobifera. Diversity (H' = 1.4-2.0) and dominance (D = 0.22-0.47) indices were similar to those for the first assemblage, but FI values were much lower (2.0-3.4). Samples characterized by this assemblage were collected only from the southern

  15. Effect of oxygen manipulations on benthic foraminifera: A preliminary experiment

    Digital Repository Service at National Institute of Oceanography (India)

    Panchang, R.; Nigam, R.; Linshy, V.; Rana, S.S.; Ingole, B.S.

    marine protists, which have a great potential to detect ecological stress at a very early stage. Due to their high fossilization potential, an understanding of the ecology of foraminifera allows interpretations of the past benthic environmental...’. Many soft-shelled forms also exist, but have not been considered in the present study as they have no fossilization potential and thereby of no geological significance. This is a preliminary report and only presents the effect of oxygen...

  16. Frequency distribution of Foraminifera in the Chilka lake

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmy, K.V.; Rao, K.K.

    for these organisms to invade the lake is that food supply is more inside an estuary than in a nearshore area. 7. The degree of faunal affinity using Bray-Curtis coefficient and Commu- nity coefficient of similarity indices for the sites in different parts... Introduction The importance of recent Foraminifera in oceanic research is well known (Boltovskoy and Wright, 1976). Conse- quently, research publications on these marine organisms of the world oceans, are cornucopian and exhaustive. A re- view...

  17. Unraveling Vital Effects: Photosynthesis of Symbiotic Algae in Foraminifera Hosts

    Science.gov (United States)

    Fish, C.; Phelps, S. R.; Goes, J. I.; Hoenisch, B.

    2015-12-01

    B/Ca and boron isotope proxies recorded in the calcium carbonate shells of planktic foraminifera are sensitive to seawater acidity. We seek to understand how the biology of the organism affects the geochemical signals, as planktic foraminifera shells differ in their chemical composition from inorganic calcite and also between foraminifer species. These differences are most likely related to physiological processes like respiration, calcification, and photosynthesis in symbiont-bearing foraminifera. The modifications of geochemical signals by these biological parameters are termed vital effects. Our study is based on the hypothesis that the B/Ca and δ11B offsets observed in planktic foraminifer shells are primarily due to the photosynthetic activity of their symbionts, which may elevate the microenvironmental pH to different degrees in different foraminifer species. Using fast repetition rate fluorometry, chlorophyll α analyses and symbiont counts, we investigated the symbiont-photosynthetic activity associated with three foraminifera species - Globigerinoides ruber, G. sacculifer, and Orbulina universa. Boron proxy systematics in these species suggest that photosynthetic activity should be greater in G. ruber compared to G. sacculifer and O. universa, but this is not confirmed by our study. While symbiont photosynthesis undoubtedly explains microenvironmental pH-elevation and boron proxy systematics in symbiont-bearing compared to symbiont-barren foraminifer species, additional processes must be responsible for the boron geochemical offsets between symbiont-bearing species. Respiration of the symbiont-host association and the calcification process are most likely candidates that require further analysis. Our study highlights the potential danger of misinterpreting geochemical signals in biological organisms when the biology of the organism in question is not entirely understood.

  18. Wielician foraminifera at the western border of the Transylvanian Basin

    Directory of Open Access Journals (Sweden)

    Sorin Filipescu

    2001-09-01

    Full Text Available Marine Middle Miocene deposits at the top of Gârbova de Sus Formation preserve a particular foraminifera assemblage, with both benthic and planktonic taxa. Presence of several biostratigraphic significant species allowed an extension of the known age of the formation, up to Wielician. The morphogroups also suggest a deeper environment, compared to the rest of the formation. The change of fauna type at this level might be correlated to the start of a new global cycle.

  19. Early to middle Miocene foraminifera from the deep-sea Congo Fan, offshore Angola

    OpenAIRE

    Kender, S; Kaminski, M.A.; Jones, R W

    2008-01-01

    Analysis of a 630m section of an exploration well penetrating the distal part of the Congo Fan (~2000m water depth) yielded high abundance and diversity assemblages of agglutinated and calcareous benthic foraminifera. Planktonic foraminifera constrain the age to Early – Middle Miocene, and \\delta 18O records reveal the Mi1 (~16.3 Ma) isotopic shift. Relatively few taxonomic studies of deep-water calcareous and agglutinated benthic foraminifera exist from this time period in this loca...

  20. How to react to shallow water hydrodynamics: The larger benthic foraminifera solution

    OpenAIRE

    Briguglio, Antonino; Hohenegger, Johann

    2011-01-01

    Symbiont-bearing larger benthic foraminifera inhabit the photic zone to provide their endosymbiotic algae with light. Because of the hydrodynamic conditions of shallow water environments, tests of larger foraminifera can be entrained and transported by water motion. To resist water motion, these foraminifera have to build a test able to avoid transport or have to develop special mechanisms to attach themselves to substrate or to hide their test below sediment grains. For those species which r...

  1. MIDDLE TRIASSIC FORAMINIFERA FROM THE SECEDA CORE (DOLOMITES, NORTHERN ITALY

    Directory of Open Access Journals (Sweden)

    FLORIAN MAURER

    2002-11-01

    Full Text Available The assemblage of foraminifera in turbidite beds in Middle Triassic basinal deposits straddling the Anisian/Ladinian boundary interval was studied in 224 thin sections. The fauna consists mainly of shallow-water inhabitants, associated with calcareous hyaline foraminifera (Lagenina of open marine environment. Due to a well established  biostratigraphy in the studied interval, the first and last appearance of some shallow water, benthic foraminifera can be assigned to the Mid Triassic ammonoid stratigraphy. The species Meandrospira dinarica Kochansky-Devidè & Pantic and Arenovidalina chialingchiagensis Ho are limited to the Reitzi ammonoid zone. The species Variostoma alta Kristan and Hoyenella gr. sinensis both do not superate the Curionii zone in age in the studied succession.  The biostratigraphic most important event occurs at the base of the Gredleri zone,  with the appearance of the family Involutinidae Bütschli, represented by the genera Lamelliconus and Aulotortus. The faunal composition is similar to those of neighbouring paleoprovinces, but generally a lower faunistical diversification compared to foraminiferal assemblages in the Anisian or Carnian is observed.   

  2. Modern foraminifera assemblages in the Amundsen Sea Embayment

    Science.gov (United States)

    Ewa Jernas, Patrycja; Kuhn, Gerhard; Hillenbrand, Claus-Dieter; Lander Rasmussen, Tine; Forwick, Matthias; Mackensen, Andreas; Schröder, Michael; Smith, James; Klages, Johann Philipp

    2015-04-01

    The West Antarctic Ice Sheet (WAIS) is considered the most unstable part of the Antarctic Ice Sheet. As the WAIS is mostly grounded below sea level, its stability is of great concern. A collapse of large parts of the WAIS would result in a significant global sea-level rise. At present, the WAIS shows dramatic ice loss in its Amundsen Sea sector, especially in Pine Island Bay. Pine Island Glacier (PIG) is characterised by fast flow, major thinning and rapid grounding-line retreat. Its mass los over recent decades is generally attributed to melting caused by the inflow of warm Circumpolar Deep Water (CDW). Future melting of PIG may result in a sea level tipping point, because it could trigger widespread collapse of the WAIS, especially when considering ongoing climate change. Our research project aims to establish proxies (integration of foraminifera, sediment properties and oceanographic data) for modern environmental conditions by analysing seafloor surface sediments along a transect from the glacier proximal settings to the middle-outer shelf in the eastern Amundsen Sea Embayment. These proxies will then be applied on sediment records spanning the Holocene back to the Last Glacial Maximum for reconstructing spatial and temporal variations of CDW upwelling and ice-ocean interactions during the past c. 23,000 years. We will present preliminary results from the analyses of ten short marine sediment cores (multi and box cores) collected during expeditions JR179 (2008) and ANT-XXVI/3 (2010) along a transect from inner Pine Island Bay to the middle-outer shelf part of the Abbot Palaeo-Ice Stream Trough at water depths ranging from 458 m (middle shelf) to 1444 m (inner shelf). The sediment cores are currently investigated for distribution patterns of planktonic and benthic foraminifera and grain-size distribution at 1 cm resolution. Core tops (0-10 cm) were stained with Rose Bengal for living benthic foraminifera investigations. The chronology of the cores will be based

  3. Agglutinated foraminifera from the Ludlow (Silurian) of Ireland

    Science.gov (United States)

    Kaminski, Michael; Ferretti, Annalisa; Messori, Fabio; Papazzoni, Cesare Andrea; Sevastopulo, George

    2017-04-01

    Agglutinated foraminifera are one of the most primitive groups of foraminifera, possibly already appearing in the Cryogenian but usually rare in lower Paleozoic rocks. Their mean standing diversity slowly increased during Cambrian and Ordovician times, reaching a stable value of about 50 genera in the mid-Silurian which remained fairly constant up to the Triassic. An assemblage of agglutinated foraminifera was unexpectedly found in conodont residue from material collected in the Dingle Peninsula, County Kerry, southwestern Ireland. This material comes from rare calcareous occurrences in volcanoclastics previously known for their rich trilobite and conodont assemblages. The limestones are trilobite-crinoidal silty wackestone to packstone, with local brachiopod concentrations, documenting brachiopod-trilobite-crinoidal dominated communities of shallow and well-ventilated water that might have periodically colonized the bottom intercalating with volcanic events and then successively redeposited in deeper waters. The conodont fauna indicates an early Ludlow (Gorstian-earliest Ludfordian) age (Kaminski et al., 2016). The foraminiferal assemblage has limited potential for stratigraphical correlation as long-range taxa are present, but it represents the first record from the Silurian of Ireland. The assemblage is dominated by tubothalamids (Rectoammodiscus and rare Sansabaina), with less abundant monothalamids (Psammosiphonella and Psammosphaera). The assemblage displays low diversity compared with other assemblages described from the British Isles (Kircher & Brasier, 1989). At the species level, this assemblage is identical to those described previously from the Silurian of North America but with lower diversity. Only Rectoammodiscus diai had apparently a wider geographic distribution, including not only the central USA (Oklahoma and Kansas) but also the Welsh Borderlands and Senegal. The affinities with the assemblages reported at several localities in the central

  4. ENVIRONMENTAL CONTROL OF NANNOPLANKTON AND FORAMINIFERA ASSEMBLAGES IN MADURA WATERS

    Directory of Open Access Journals (Sweden)

    Vijaya Isnaniawardhani

    2017-07-01

    Full Text Available Nannoplankton is widely used for determining age of sediments following the other microorganism foraminifera since the late 1960s; and it was started being used for marine geography study in the year of 1984. This topic interests to be done in Indonesia as one of the tropic region. The research covered a study about environment using nannoplankton and it is compared with the same study using foraminifera. Methods of the study include: (1 collecting secondary data and samples; (2 collecting field data record; (3 laboratory analyses upon sediment samples to determine the content of nannoplankton and foraminifera (micropaleontology analyses, the texture and composition of minerals (by means of grain size, petrology megascopic and microscopic analyses (4 intergrating all of the analyses result. Madura waters can be divided into four zones, among all : (I inner shelf (water depth less than 30 m in Madura Strait, (II inner shelf in open marine north of Madura, (III outer shelf (water depth 30 to 80 m in Madura Strait, and (IV outer shelf in open marine north of Madura. Inner shelf in the Madura Strait (Zone I is characterized by less than 1% sediment of nannoplankton (are made up of Gephyrocapsa oceanica; rare assemblages of benthic foraminifera only (Ammonia spp., arenaceous carbonate test taxa such as : Ammobaculites spp., Textularia agglutinans, Haplophragmoides spp., and milliolidae. Inner shelf open marine north of Madura (Zone II yielded few nannoplankton assemblages, dominated by Gephyrocapsa oceanica with low number of Emiliania huxleyi, Helicosphaera carteri, H. pavimentum, H. walichii and Pontosphaera spp; common foraminifera assemblages consist of rare planktic Globigerinoides ruber, G. trilobus sacculiferus, G. conglobatus with one or two dominant benthic (Elphidium spp, Ammonia spp., Pseudorotalia spp., Asterorotalia spp.. Outer shelf of Madura Strait (Zone III assigned by common nannoplankton assemblages, dominated by Gephyrocapsa

  5. Distribution of foraminifera in the lagoons of certain Islands of the Lakshadweep Archipelago, Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Sivadas, P.; Narayanan, B.; Jayalakshmy, K.V.; Kutty, M.K.

    Foraminifera are very rare and those few present in the lagoons have been transported by water currents through passages of the reef. In general, Foraminifera of the coral reefs in the coastal waters of Indian peninsula are similar in their species composition...

  6. Morphotype patterns of Norwegian Sea deep-sea benthic foraminifera and ecological implications

    Science.gov (United States)

    Corliss, Bruce H.; Chen, Christina

    1988-08-01

    Deep-sea benthic foraminifera from Norwegian Sea surface sediments are classified into morphotypes on the basis of test shape and nature of test coiling and show distinct patterns with water depth. The morphotype data are used to determine microhabitat patterns of the foraminifera, which are suggested to be related to the organic-carbon content of the surficial deep-sea sediments.

  7. First planktonic foraminifera from the Early Cretaceous (Albian) of the Upper Magdalena Valley, Colombia

    Science.gov (United States)

    Blau, J.; Vergara, L.; Stock, H. W.

    1992-10-01

    Albian planktonic foraminifera have been found in the Caballos and "Villeta" formations at two localities in the Upper Magdalena Valley. This is the first documented record of Early Cretaceous planktonic foraminifera in Colombia. Hedbergellids and heterohelicids predominate; keeled forms are absent. The sedimentologic features and the associated microfauna indicate the onset of restricted environments from the middle Albian on.

  8. Fluorescent observations of calcium ion activity in living benthic foraminifera

    Science.gov (United States)

    Toyofuku, T.; de Nooijer, L. J.; Kitazato, H.

    2009-04-01

    Foraminifera are one of the main sources of marine biogenic carbonate and are commonly used to reconstruct paleoenvironments. However, little is known about the intracellular control on elements. In particular, knowledge on calcium ion activities in living foraminiferal cells is of great interest, since it may have implications for many studies in paleoceanography. Recently, fluorescent calcium indicators have been developed that can be used to observe calcium ion activities within a living foraminiferal cell directly. In this study, we applied the fluorescent calcium indicator Fluo-3 AM to observe intracellular calcium ion mobility within one species of a shallow water benthic foraminifers. We show that with this fluorescent calcium indicator is possible to 1) perform real time calcium observations, and 2) study intracellular calcium ion distribution of foraminifera during calcification. We incubate living foraminiferal specimens under two conditions, one under Fluo-3 AM solution in normal filtrated seawater and the other Fluo-3 AM solution in calcium-free artificial seawater. Fluorescence was seen all over foraminiferal cell in specimens incubated in Fluo-3 AM/normal seawater, while there are no fluorescence was observed in individuals that were incubated with Fluo-3 AM in calcium-free artificial seawater, though the specimens extend their pseudopodia actively under both conditions. Therefore the observed fluorescence should be indicated the calcium ion existence. This method may allow us detailed real-time observation of in-vivo calcium activities in foraminiferal cell. It may be over the many limitations of the existing methods to trace calcium uptake of foraminifera.

  9. Salinity controls on Na incorporation in Red Sea planktonic foraminifera

    Science.gov (United States)

    Mezger, E. M.; Nooijer, L. J.; Boer, W.; Brummer, G. J. A.; Reichart, G. J.

    2016-12-01

    Whereas several well-established proxies are available for reconstructing past temperatures, salinity remains challenging to assess. Reconstructions based on the combination of (in)organic temperature proxies and foraminiferal stable oxygen isotopes result in relatively large uncertainties, which may be reduced by application of a direct salinity proxy. Cultured benthic and planktonic foraminifera showed that Na incorporation in foraminiferal shell calcite provides a potential independent proxy for salinity. Here we present the first field calibration of such a potential proxy. Living planktonic foraminiferal specimens from the Red Sea surface waters were collected and analyzed for their Na/Ca content using laser ablation quadrupole inductively coupled plasma mass spectrometry. Using the Red Sea as a natural laboratory, the calibration covers a broad range of salinities over a steep gradient within the same water mass. For both Globigerinoides ruber and Globigerinoides sacculifer calcite Na/Ca increases with salinity, albeit with a relatively large intraspecimen and interspecimen variability. The field-based calibration is similar for both species from a salinity of 36.8 up to 39.6, while values for G. sacculifer deviate from this trend in the northernmost transect. It is hypothesized that the foraminifera in the northernmost part of the Red Sea are (partly) expatriated and hence should be excluded from the Na/Ca-salinity calibration. Incorporation of Na in foraminiferal calcite therefore provides a potential proxy for salinity, although species-specific calibrations are still required and more research on the effect of temperature is needed.

  10. Deep Sea Benthic Foraminifera: Love Cold, Fear Warm

    Science.gov (United States)

    Thomas, E.

    2007-12-01

    The fossil record provides understanding of possible linkages between long-term environmental changes and evolution of assemblages and morphological species of deep-sea benthic foraminifera, of which the phylogeny is still little known. Deep-sea benthic foraminifera have long morphological species lives and do not commonly suffer massive extinctions: they live in the largest habitat on earth, species have large geographic ranges or are cosmopolitan, and they use motile propagules to rapidly re-populate regions where populations have been destroyed. Extinction occurs only when rapid and severe environmental change affects such a large part of the deep ocean that no refugia exist, even for common species. Deep-sea benthic foraminifera reacted to global cooling (in the earliest Oligocene, middle Miocene and middle Pleistocene) not by extinction, but by a gradual turnover of species. The most extensive turnover occurred in the late Eocene through earliest Oligocene, when some presently important ecological niches were first filled. In contrast, deep-sea benthic foraminifera suffered severe extinction (30-50% of species, including common, cosmopolitan, long-lived species) during the rapid global warming of the Paleocene-Eocene Thermal Maximum (PETM), a time of high CO2 levels and potential ocean acidification. The extinction was followed by slow recovery of faunas, but diversity never returned to pre-extinction levels. The PETM and later, less severe short-term periods of global warming (hyperthermals ETM1 and ETM2) were characterized by low diversity faunas dominated by small, thin-walled individuals. No significant net extinction occurred during the later hyperthermals. Such faunas might reflect dissolution, low oxygen conditions, or blooming of opportunistic species after environmental disturbance. Most commonly cited causes of the PETM extinction are: 1. low oxygen concentrations, 2. acidification of the oceans, 3. increase or decrease in oceanic productivity and

  11. Morphological and cytological responses of Ammonia (foraminifera) to copper contamination: Implication for the use of foraminifera as bioindicators of pollution

    Energy Technology Data Exchange (ETDEWEB)

    Le Cadre, Valerie [Universite d' Angers, UPRES-EA 2644, Laboratoire de Geologie, 2 Bd Lavoisier 49045 Angers cedex (France) and LEBIM - Laboratoire d' Etude des Bio-Indicateurs Marins, 85350 Ile d' Yeu (France)]. E-mail: val.jeje@wanadoo.fr; Debenay, Jean-Pierre [Universite d' Angers, UPRES-EA 2644, Laboratoire de Geologie, 2 Bd Lavoisier 49045 Angers cedex (France); LEBIM - Laboratoire d' Etude des Bio-Indicateurs Marins, 85350 Ile d' Yeu (France)

    2006-09-15

    The effect of graded concentrations of copper was analyzed at morphological and cytological levels on two species of Ammonia (foraminifera) often found in polluted areas. The two species were sensitive to low concentration, but survived high concentration (threshold value < 10 {mu}g l{sup -1}, lethal value > 200 {mu}g l{sup -1}), which gives them a high potential value as bioindicators. Increasing concentrations lead to (1) increasing delay before production of new chambers, explaining dwarfism in polluted areas; (2) increasing delay before reproduction and decreasing number of juveniles, explaining low density; and (3) increasing proportion of deformed tests. Cytological modifications occurred only in deformed specimens (thickening of the organic lining, proliferation of fibrillar and of large lipidic vesicles, increased number of residual bodies). They may be responsible for anomalies in biomineralization processes. The detection of sulfur in deformed specimens suggests that foraminifers may have a detoxification mechanism with production of a metallothionein-like protein. - Results suggest a detoxification mechanism for copper in foraminifera.

  12. Do foraminifera accurately record seawater neodymium isotope composition?

    Science.gov (United States)

    Scrivner, Adam; Skinner, Luke; Vance, Derek

    2010-05-01

    Palaeoclimate studies involving the reconstruction of past Atlantic meridional overturning circulation increasingly employ isotopes of neodymium (Nd), measured on a variety of sample media (Frank, 2002). In the open ocean, Nd isotopes are a conservative tracer of water mass mixing and are unaffected by biological and low-temperature fractionation processes (Piepgras and Wasserburg, 1987; Lacan and Jeandel, 2005). For decades, benthic foraminifera have been widely utilised in stable isotope and geochemical studies, but have only recently begun to be exploited as a widely distributed, high-resolution Nd isotope archive (Klevenz et al., 2008), potentially circumventing the difficulties associated with other methods used to recover past deep-water Nd isotopes (Klevenz et al., 2008; Rutberg et al., 2000; Tachikawa et al., 2004). Thus far, a single pilot study (Klevenz et al., 2008) has indicated that core-top sedimentary benthic foraminifera record a Nd isotope composition in agreement with the nearest available bottom seawater data, and has suggested that this archive is potentially useful on both millennial and million-year timescales. Here we present seawater and proximal core-top foraminifer Nd isotope data for samples recovered during the 2008 "RETRO" cruise of the Marion Dufresne. The foraminifer samples comprise a depth-transect spanning 3000m of the water column in the Angola Basin and permit a direct comparison between high-resolution water column and core-top foraminiferal Nd isotope data. We use these data to assess the reliability of both planktonic and benthic foraminifera as recorders of water column neodymium isotope composition. Frank, M., 2002. Radiogenic isotopes: Tracers of past ocean circulation and erosional input, Rev. Geophys., 40 (1), 1001, doi:10.1029/2000RG000094. Klevenz, V., Vance, D., Schmidt, D.N., and Mezger, K., 2008. Neodymium isotopes in benthic foraminifera: Core-top systematics and a down-core record from the Neogene south Atlantic

  13. Selective responses of benthic foraminifera to thermal pollution.

    Science.gov (United States)

    Titelboim, Danna; Almogi-Labin, Ahuva; Herut, Barak; Kucera, Michal; Schmidt, Christiane; Hyams-Kaphzan, Orit; Ovadia, Ofer; Abramovich, Sigal

    2016-04-15

    Persistent thermohaline pollution at a site along the northern coast of Israel, due to power and desalination plants, is used as a natural laboratory to evaluate the effects of rising temperature and salinity levels on benthic foraminifera living in shallow hard-bottom habitats. Biomonitoring of the disturbed area and a control station shows that elevated temperature is a more significant stressor compared to salinity, thus causing a decrease in abundance and richness. Critical temperature thresholds were observed at 30 and 35°C, the latter representing the most thermally tolerant species in the studied area Pararotalia calcariformata, which is the only symbiont-bearing species observed within the core of the heated area. Common species of the shallow hard-bottom habitats including several Lessepsian invaders are almost absent in the most exposed site indicating that excess warming will likely impede the survival of these species that currently benefit from the ongoing warming of the Eastern Mediterranean.

  14. Response of foraminifera to a reverse osmosis briny discharge

    Science.gov (United States)

    Small, Richard Eustace Aiken

    Reverse osmosis water treatment plants are becoming the preferred means of generating potable water for many eastern North Carolina communities. At these facilities, reject brine solutions---sometimes containing up to 10 times the initial concentration of dissolved solids---are created and often discharged into estuarine waters. Several state and federal agencies have expressed concern over the potential ecological impacts this wastewater could have on these sensitive environments. Monitoring of a brine discharge site in Currituck County, North Carolina revealed significantly higher conductivity values within ~50 m of the point source. One group of organisms that have proven useful in other studies for monitoring impact of anthropogenic pollution in estuaries is Foraminifera. Foraminifera are abundant microorganisms that are widespread in most marginal-marine and marine environments; nevertheless, individual taxa are highly selective of their habitat. Nearly all species build shells (tests) that are preserved in coastal sediments, allowing for reconstruction of previous marine conditions. Species abundance data was collected from surface and sub-surface samples taken in the area surrounding the brine point source. Two taxa (Ammobaculites spp. and Ammotium sp.) accounted for 98.5% of all normalized specimens. Abundance is significantly less in the sub-surface samples (Student's t-test, p<0.0001), likely due to taphonomic effects. Abundance does not appear correlated with discharge of the wastewater; instead, natural parameters appear to affect abundance in an assemblage to a greater degree. Species distribution is similar in surface and sub-surface samples. Foraminiferal diversity is significantly less near the discharge based on one sample collected within 5 m of the discharge site; samples at greater distances do not appear affected. Loss of diversity within a few meters of the discharge site is consistent with previous studies, but more data would be needed to

  15. Does temperature affect dimorphic reproduction in benthic foraminifera? A culture experiment on Rosalina leei

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Caron, D.A.

    day. A mixture of three microalgae was cultured separately and used as food (every alternate day) for living spec i- mens of foraminifera. The following species (for which stock cultures were availabl e at Woods Hole Ocean o- graphic Institution...

  16. The reciprocity between coiling direction and dimorphic reproduction in benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.

    There are various opinions as to what parameter influences the coiling directions in foraminifera. "Do microspheric and megalospheric generations have different coiling ratios?" is an unanswered question in foraminiferal studies. Per view of this...

  17. Sediment traps as a new tool for estimation of longevity of planktonic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    Sediment trap technique provides time series data of sinking particles (faunal and sediment) from surface to bottom of the sea. Besides many other applications, data can also be used to estimate life span of planktonic foraminifera. Based on rearing...

  18. Planktonic foraminifera from a quaternary deep sea core from the southern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Rao, P.S.; Pattan, J.N.

    An investigation on planktonic foraminifera and calcium carbonate content of a box core collected at a depth of 2556 m from the southern part of the Arabian sea indicates faunal changes depicting Quaternary climatic fluctuations. Based on the study...

  19. Response of benthic foraminifera Rosalina leei to different temperature and salinity, under laboratory culture experiment

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Kurtarkar, S.R.; Saraswat, R.; Linshy, V.N.; Rana, S.S.

    and 35 ppt saline water is most suitable for the growth of R. leei. Results are significant as the responses of benthic foraminifera to different temperatures and salinity are being used for palaeoclimatic reconstruction....

  20. Benthic foraminifera show some resilience to ocean acidification in the northern Gulf of California, Mexico.

    Science.gov (United States)

    Pettit, L R; Hart, M B; Medina-Sánchez, A N; Smart, C W; Rodolfo-Metalpa, R; Hall-Spencer, J M; Prol-Ledesma, R M

    2013-08-30

    Extensive CO2 vents have been discovered in the Wagner Basin, northern Gulf of California, where they create large areas with lowered seawater pH. Such areas are suitable for investigations of long-term biological effects of ocean acidification and effects of CO2 leakage from subsea carbon capture storage. Here, we show responses of benthic foraminifera to seawater pH gradients at 74-207m water depth. Living (rose Bengal stained) benthic foraminifera included Nonionella basispinata, Epistominella bradyana and Bulimina marginata. Studies on foraminifera at CO2 vents in the Mediterranean and off Papua New Guinea have shown dramatic long-term effects of acidified seawater. We found living calcareous benthic foraminifera in low pH conditions in the northern Gulf of California, although there was an impoverished species assemblage and evidence of post-mortem test dissolution.

  1. An experimental mesocosm study of microhabitat preferences and mobility in benthic foraminifera: Preliminary results.

    NARCIS (Netherlands)

    Ernst, S.R.; Duijnstee, Ivo; Jannink, N.T.; van der Zwaan, Bert

    2001-01-01

    Three small microcosm experiments were carried out to study the microhabitat preferences and mobility of benthic foraminifera from the northern Adriatic Sea. Following initial homogenization, the foraminiferal assemblages developed a clear microhabitat partitioning in the microcosms within 20 days.

  2. The use of fossil benthic foraminifera to define reference conditions for present-day marine waters

    Science.gov (United States)

    Bouchet, V. M. P.; Hess, S.; Dolven, J. K.; Alve, E.

    2012-04-01

    The implementation of legislations is generating a fruitful debate amongst marine scientists about how to define efficient and reliable bio-assessment tools to monitor the ecological quality status (EcoQS) of marine waters. According to those legislations, EcoQS assessment needs a "reference condition" with which to compare the present-day condition at a site. The fossil record has a potential to reconstruct PaleoEcoQS and thereby establish in situ reference conditions from pre-impact times. Unlike most macrofaunal groups which are the most commonly used biological quality indicator in these environments, benthic foraminifera leave a fossil record and therefore allow the reconstruction of human-induced environmental disturbance over decades to centuries. Foraminifera have the potential to serve as ecosystem characterization tools in modern and past marine environments. We compared the response of benthic foraminifera, macrofauna and selected environmental parameters from the same sites in areas with relatively stable salinity and temperature conditions but otherwise contrasting environmental properties (e.g., varying degree of anthropogenic impact). In August 2008, replicate samples for living (stained) benthic foraminifera and macrofauna from 27 stations in 11 silled fjords along the Norwegian Skagerrak coast were examined. Environmental data (bottom-water dissolved-oxygen, TOC, TN and pigments) were analysed for each station. The same kind of data were analysed from 2 recolonisation sites in the inner Oslofjord. In addition, the PaleoEcoQS during the past century was reconstructed using benthic foraminifera and selected environmental parameters from 11 stations in the inner Oslofjord. Results show that living benthic foraminifera are at least as reliable to define present-day EcoQS as conventional methods. Fossil benthic foraminifera can also define ecological status of reference conditions from pre-impacted times. This is not possible using conventional methods

  3. Metal:Calcite Distribution Coefficients of Laboratory-Grown Bathyl Benthic Foraminifera

    Science.gov (United States)

    Hintz, C. J.; Shaw, T. J.; Bernhard, J. M.; Chandler, G. T.; McCorkle, D. C.; Blanks, J. K.

    2002-12-01

    Benthic foraminifera, collected from sediments off the Carolina coast, were maintained in mono- and multi-species cultures for four and a half months in a sediment-free culture system. The foraminifera were cultured in a closed system using a 1600-liter modified artificial seawater reservoir. The temperature, alkalinity, stable isotope ratios, and trace metal concentrations were held static in seawater medium during the experiment. The artificial seawater was circulated from the reservoir through nine 3 mL acrylic microcosms that contained 80-100 foraminifera living in ~1 mm thick silica substrate. Foraminifera were labeled with fluorescent calcein, prior to addition to the microcosms, to provide a clear demarcation between parent calcite and cultured calcite. At the end of the experiment juvenile Bulimina aculeata were harvested from the microcosms (~150-3000 specimens per microcosm). The cultured foraminifera were divided into two groups for separate trace metal analyses and stable isotope analyses. The foraminifera from the trace metal splits were cleaned and analyzed for Ca, Ba, and Cd by isotope dilution ICP-MS. Barium distribution coefficients were close to previously reported values of cultured foraminiferal calcite but remained lower than reported field data. Preliminary Ba:Ca distribution coefficients for B. aculeata do not appear to indicate strong life stage differences, even though there are indications of ontogenetic variations in δ13C for this species (see McCorkle et al. abstract).

  4. Planktonic foraminifera in the Arctic: potentials and issues regarding modern and quaternary populations

    Energy Technology Data Exchange (ETDEWEB)

    Eynaud, Frederique, E-mail: f.eynaud@epoc.u-bordeaux1.fr [Universite Bordeaux I, Laboratoire EPOC (Environnements et Paleoenvironnements OCeaniques), UMR CNRS 5805, Avenue des facultes, 33405 Talence cedex - France (France)

    2011-05-15

    Calcareous microfossils are widely used by paleoceanographers to investigate past sea-surface hydrology. Among these microfossils, planktonic foraminifera are probably the most extensively used tool (e.g. [1] for a review), as they are easy to extract from the sediment and can also be used for coupled geochemical (e.g; {delta}{sup 18}O, {delta}{sup 13}C, Mg/Ca) and paleo-ecological investigations. Planktonic foraminifera are marine protists, which build a calcareous shell made of several chambers which reflect in their chemistry the properties of the ambient water-masses. Planktonic foraminifera are known to thrive in various habitats, distributed not only along a latitudinal gradient, but also along different water-depth intervals within surface waters (0-1000 m). Regarding their biogeographical distribution, planktonic foraminifera assemblages therefore mirror different water-masses properties, such as temperature, salinity and nutrient content of the surface water in which they live. The investigation of the specific composition of a fossil assemblage (relative abundances) is therefore a way to empirically obtain (paleo)information on past variations of sea-surface hydrological parameters. This paper focuses on the planktonic foraminifera record from the Arctic domain. This polar region records peculiar sea-surface conditions, with the influence of nearly perennial sea-ice cover development. This has strong impact on living foraminifera populations and on the preservation of their shells in the underlying sediments.

  5. Quantitative vertical zonation of salt-marsh foraminifera for reconstructing former sea level : an example from New Jersey, USA

    OpenAIRE

    Kemp, Andrew C.; Horton, Benjamin P.; Vann, David R.; Engelhart, Simon E.; Grand Pre, Candace A.; Vane, Christopher H.; Nikitina, Daria; Anisfeld, Shimon C.

    2012-01-01

    We present a quantitative technique to reconstruct sea level from assemblages of salt-marsh foraminifera using partitioning around medoids (PAM) and linear discriminant functions (LDF). The modern distribution of foraminifera was described from 62 surface samples at three salt marshes in southern New Jersey. PAM objectively estimated the number and composition of assemblages present at each site and showed that foraminifera adhered to the concept of elevation-dependent ecological zones, makin...

  6. Effect of varying frontal systems on stable oxygen and carbon isotopic compositions of modern planktic foraminifera of Southern Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Tiwari, M.; Mohan, R.; Meloth, T.; Naik, S.S.; Sudhakar, M.

    , sediment cores and other physi- cal oceanographic parameters were collected. Here, we present the isotopic results obtained from planktic foraminifera from the plankton net samples and sur- face sediments. We find that, in this region too, plank- tic... characteristics in the Indian sector of the Southern Ocean. The δ 18 O value of planktic foraminifera is mainly governed by SST fluctuations: the samples be- come isotopically heavier polewards. Further, the plank- tic foraminifera appear to secrete...

  7. Evaluating Foraminifera as an Archive for Seawater Chromium Isotopic Composition

    Science.gov (United States)

    Wang, X.; Planavsky, N.; Hull, P. M.; Tripati, A.; Reinhard, C.; Zou, H.; Elder, L. E.; Henehan, M. J.

    2015-12-01

    In recent years there has been growing interest in using chromium isotopes (δ53Cr) as a proxy to investigate the redox evolution of Earth's ocean-atmosphere system throughout geological history. Potential archives for seawater δ53Cr that have been identified to date include iron formations and organic-rich siliciclastic sediments. However, these types of sediments are not common and they are discontinuous over geologic time. As a result, alternative types of archives are needed. Here we evaluate the utility of foraminifera tests as a recorder of seawater δ53Cr. Core-tops used were from different ocean basins. Mono-specific samples of Globigerinoides sacculifer, Orbulina universa, Pulleniatina obliquiloculata, Globoratalia crassula-crassaformis, Globoratalia truncatulinoides, and Globigerinella siphonifera were isolated to investigate inter-species isotope fractionation. Chromium concentrations were measured by isotope dilution method to be 0.1-0.3 μg/g. The δ53Cr values of these species range from 0.2‰ to 2.4‰, with an analytical uncertainty of 0.3‰ (95% confidence). Despite the high analytical uncertainty due to the extremely low levels of Cr present, there is still large detectable variation in foraminiferal δ53Cr values, which overlap presently available seawater values (Bonnand et al., 2013; Scheiderich et al., 2015). Possible explanations for such variations in foraminiferal δ53Cr values include heterogeneity of seawater δ53Cr in the modern oceans, and/or photobiochemical redox cycling of Cr in the surface oceans. Therefore, care should be taken when using foraminifera to reconstruct past seawater δ53Cr values. ReferencesBonnand, P., James, R., Parkinson, I., Connelly, D., Fairchild, I., 2013. The chromium isotopic composition of seawater and marine carbonates. Earth and Planetary Science Letters, 382: 10-20. Scheiderich, K., Amini, M., Holmden, C., Francois, R., 2015. Global variability of chromium isotopes in seawater demonstrated by Pacific

  8. Effect of Cretaceous oceanic anoxic events on the evolutionary trend of planktonic foraminifera

    Science.gov (United States)

    Kuroyanagi, A.; Ozaki, K.; Kawahata, H.

    2014-12-01

    It is widely thought that oceanic redox state is essential for the evolutionary history of life on the earth, and "anoxic events" have been proposed as one of the causal mechanisms for mass extinctions. During mid-Cretaceous, widely known as the extremely warm period, oceanic anoxic events (OAEs) occurred several times and they would have caused a substantial impact on the biosphere. Planktonic foraminifera are marine planktons with calcite tests and their productions constitute ~30-80% of the modern deep-marine calcite budget, thus they play an important role in the global carbon cycle. Previous study reported that planktonic foraminifera displayed the high turnover (extinction and speciation) rate at or near the major OAEs. However, the impact of Cretaceous OAEs on the evolutionary trend of planktonic foraminifera remains obscure. In this study, we investigated the role of spatiotemporal extent of anoxia on the evolutionary trend of planktonic foraminifera by assessing the extinction/speciation rate of planktonic foraminifera around Cretaceous OAEs. The number of foraminiferal species increased across the OAE1a and then showed a peak after this episode. Around OAE2, several planktonic foraminifera species became extinct and several speciated, however, long-term trends in foraminiferal evolution showed no drastic changes near the event. Therefore these results suggest that the ocean surface environment at OAEs would not have a direct effect on foraminiferal extinction/speciation. This interpretation is reinforced when considering the recent culturing results, which demonstrate that modern planktonic foraminifera have a high tolerance to extremely low dissolved oxygen levels than expected. Accumulating geochemical data also suggest a spatial heterogeneity of oceanic anoxia/euxinia during OAE2. These results lead us to conclude that Cretaceous OAEs would not directly related to planktonic foraminiferal extinction due to regional distribution of anoxia/euxinia.

  9. Molecular evidence for host-symbiont specificity in soritid foraminifera.

    Science.gov (United States)

    Garcia-Cuetos, Lydia; Pochon, Xavier; Pawlowski, Jan

    2005-12-01

    Symbiosis between the dinoflagellate genus Symbiodinium and various invertebrates and protists is an ubiquitous phenomenon in shallow tropical and subtropical waters. Molecular studies undertaken on cnidarian symbionts revealed the presence of several distinctive lineages or subgeneric clades of Symbiodinium whose taxonomic level provides limited information about the specificity between invertebrate hosts and their symbionts. This contrasts with the finding of several Symbiodinium clades being present almost exclusively in foraminifera and belonging to the subfamily Soritinae. To test whether such specificity also exists at a lower taxonomic level within Soritinae, we obtained the SSU rDNA sequences from 159 soritid individuals collected in nine localities worldwide and representing all known morphospecies of this subfamily. For each individual, the symbionts were determined either by sequencing or by RFLP analysis. We distinguished 22 phylotypes of Soritinae in relation with a number of symbiont "groups" corresponding to 3 clades and 5 subclades of Symbiodinium. Among the 22 soritid phylotypes, 14 show strict symbiont specificity and only one was found to be a host for more than two "groups" of Symbiodinium. It is suggested that the strong host-symbiont specificity observed in Soritinae is a combined effect of a selective recognition mechanism, vertical transmission of symbionts, and biogeographical isolation.

  10. The distribution of Symbiodinium diversity within individual host foraminifera

    Science.gov (United States)

    Fay, S. A.; Weber, M. X.; Lipps, J. H.

    2009-09-01

    While one-to-one specificity between reef-dwelling hosts and symbiotic dinoflagellates of the genus Symbiodinium may occur, detailed examination of some hosts reveals that they contain multiple symbiont types. Individuals of the foraminifer Amphisorus hemprichii living in Papua New Guinea contained mixed communities of Symbiodinium dominated by symbiont types in clades C and F. Moreover, the types showed a distinct pattern in their distribution across the radius of the foraminifer, with clade F Symbiodinium more prevalent in the center of the host cell. The mixed community of symbionts and their pattern of distribution within the foraminifer is likely the result of processes happening both inside the foraminifer and in its external environment. Persistent mixed symbiont communities in foraminifera may be stabilized through benefits conferred by maintaining multiple symbiont lineages for symbiont shuffling. Alternatively they may be stabilized through a heterogeneous internal host environment, partitioning of symbiont functional roles or limitation of symbiont reproduction by the host. Six factors generally determine the presence of any particular symbiont type within a foraminifer: mode of transmission, availability from the environment, recognition by the host, regulation by the host, competition between lineages, and fitness of the holobiont.

  11. Post-depositional alteration of benthic foraminifera in a methane seep environment

    Science.gov (United States)

    Schneider, Andrea; Cremiere, Antoine; Panieri, Giuliana; Lepland, Aivo; Knies, Jochen

    2016-04-01

    Benthic foraminifera tests from the sediment cores taken from the Vestnesa Ridge, one of the northernmost known marine methane hydrate reservoir, were studied for their visual appearance, mineral and stable carbon isotopic composition in order to explore their indicator potential in a methane seep environment. The Vestnesa Ridge is a sediment drift located in 1200m water depth at 79°N at Svalbard's northwestern continental margin. Observations of gas flares originating from pockmarks that are aligned along the crest of the ridge show ongoing methane emission. A distinct sediment layer containing a fossilized assemblage of chemosynthetic bivalves indicates methane seepage activity at least in the late Pleistocene. We have examined the state of preservation and geochemical characteristics of foraminifera tests from this bivalve shell horizon. Tests of the benthic foraminifera species Cassidulina neoteretis display a variable degree of post-depositional alteration and formation of diagenetic carbonate overgrowths on calcitic primary tests. Using binoculars, scanning electron microscope imagery and energy dispersive x-ray spectroscopy, we distinguish visually and mineralogically different diagenetic phases on the external and internal test surfaces. Pristine and smooth test surfaces act as nucleation templates for precipitation of authigenic Mg-calcite crystals causing complete filling of chambers and encrustation of the external test surfaces. The presence of Mg-calcite indicates the overgrowth is precipitating in sulfate-poor sediments. In addition to benthic foraminifera, we have studied the mineralogical and stable carbon and oxygen isotope composition of authigenic carbonate nodules found in the bivalve shell horizon. The mineralogical nature of the carbonates and overgrowths on the foraminifera tests were found to be identical. The δ13C value of the carbonate nodules is as low as -32.3‰ indicating their methane-derived origin. Authigenic carbonate coated

  12. Recent benthic foraminifera assemblages from mangrove swamp and channels of Abu Dhabi (UAE)

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.; Odeh, Weaam A. S. Al; Paul, Andreas; Song, Jianfeng; Freeman, Mark; Michel, Françoise

    2017-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Persian/Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations from mangrove swamps and channels located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of benthic foraminifera in different sedimentary facies in the mangal and in the surrounding natural environments of the upper and lower intertidal area (mud flats and channels). A 100 m transect across a natural channel in a mangal on the eastern side of Abu Dhabi Island was sampled in detail for sedimentological and foraminiferal analysis. Forty-seven samples were collected at 2 meter intervals along the transect in a number of different sedimentary facies including; fine sediment in areas exposed during low tide and close to mangrove trees (Avicennia marina), fine sediment rich in leaf material, coarse sediment in channels, and coarse sediments with a shell lag. At each sampling location environmental parameters were recorded, including water depth, salinity, temperature and pH. Samples collected for foraminiferal analysis were stained in rose Bengal in order to identify living specimens. Samples collected on the mud flat at the margin of the channel show a living foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Cribroelphidium, Triloculina, Quinqueloculina, Sigmoilinita, Spiroloculina, Peneroplis and Spirolina. Samples collected in the lower (wet) intertidal area close to Avicennia marina roots, presented a low-diversity assemblage mostly comprising small-sized opportunistic foraminifera of the genera Ammonia and Cribroelphidium along with rare Triloculina and

  13. Response of benthic foraminifera to phytodetritus in the eastern Arabian Sea under low oxygen conditions

    Science.gov (United States)

    Enge, Annekatrin; Wukovits, Julia; Wanek, Wolfgang; Watzka, Margarete; Witte, Ursula; Hunter, William; Heinz, Petra

    2016-04-01

    At water depths between 100 and 1500 m a permanent Oxygen Minimum Zone (OMZ) impinges on the sea floor in the eastern Arabian Sea, exposing benthic organisms to anoxic to suboxic conditions. The flux of organic matter to the sea floor is relatively high at these depths but displays seasonal variation. Deposition of relatively fresh phytodetrital material (phytoplankton remains) can occur within a short period of time after monsoon periods. Several organism groups including foraminifera are involved to different extent in the processing of phytodetritus in the OMZs of the northern Arabian Sea. A series of in situ feeding experiments were performed to study the short-term processing (nutritional demands of foraminifera at different oxygen concentrations on the continental margin in the eastern Arabian Sea. For the experiments, a single pulse of isotopically labeled phytodetritus was added to the sediment along a depth transect (540-1100 m) on the Indian Margin, covering the OMZ core and the lower OMZ boundary region. Uptake of phytodetritus within 4 days shows the relevance of phytodetritus as food source for foraminifera. Lower content of phytodetrital carbon recorded in foraminifera from more oxygenated depths shows greater food uptake by foraminifera in the OMZ core than in the OMZ boundary region. The foraminiferal assemblage living under almost anoxic conditions in the OMZ core is dominated by species typically found in eutroph environments (such as Uvigerinids) that are adapted to high flux of organic matter. The elevated carbon uptake can also result from missing food competition by macrofauna or from greater energy demand in foraminifera to sustain metabolic processes under hypoxic stress. Variable levels and ratios of phytodetrital carbon and nitrogen indicate specific nutritional demands and storage of food-derived nitrogen in some foraminifera species under near anoxia where the mean phytodetrital nitrogen content in foraminifera was elevated. In summary

  14. Geochemistry of trace elements and Sr- Nd isotopes of foraminifera shell from the Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Trace elemental associations and Sr - Nd isotopic compositions are of important to recognition of biogenic material from mixed marine sediments. The foraminifera shell from the Okinawa Trough strongly enrichesSr, P, Mn andBa, enriches Li, U, Th, Sc, Co, Cu, Pb, Zn, Cr, Rb, Y, Sb and light rare earth elements, slightly enriches V, Ga, Zr, Nb, Cd and middle rare earth elements,is short of Mo, In, Sn, Cs, Hf, Ta, W, Ti, Bi and heavy rare earth elements. The mechanism of elemental enrichment in forminifera is the concentrations of trace elements in sea water and selective absorption of trace elements during foraminifera living, as well as the geochemical affinity between major elements and trace elements. The REE (rare earth elements) partition pattern of foraminifera shell of the Okinawa Trough shows enrichment of middle rare earth elements with slightly negative Ce anomaly,which are different from those of foraminifera of the Pacific Ocean. The Sr, Nd isotopic ratios of the Okinawa Trough foraminifera are 0.709 769 and 0.512 162, respectively, which are different not only from those of oceanic water, but also from those of river water of China's Mainland, the former is slightly higher than those of oceanic water, but much lower than those of river water; the latter is slightly lower than those of oceanic water, but higher than those of river water, demonstrating that the Okinawa Trough sea water has been influenced by river water of China's Mainland.

  15. Effects of lead pollution on Ammonia parkinsoniana (foraminifera: ultrastructural and microanalytical approaches

    Directory of Open Access Journals (Sweden)

    F. Frontalini

    2015-01-01

    Full Text Available The responses of Ammonia parkinsoniana (Foraminifera exposed to different concentrations of lead (Pb were evaluated at the cytological level. Foraminifera-bearing sediments were placed in mesocosms that were housed in aquaria each with seawater of a different lead concentration. On the basis of transmission electron microscopy and environmental scanning electron microscopy coupled with energy dispersive spectrometer analyses, it was possible to recognize numerous morphological differences between untreated (i.e., control and treated (i.e., lead enrichment specimens. In particular, higher concentrations of this pollutant led to numerical increase of lipid droplets characterized by a more electron-dense core, proliferation of residual bodies, a thickening of the organic lining, mitochondrial degeneration, autophagosome proliferation and the development of inorganic aggregates.  All these cytological modifications might be related to the pollutant-induced stress and some of them such as the thickening of organic lining might suggest a potential mechanism of protection adopted by foraminifera

  16. Discovery and features of vertical zonations of tidal salt-marsh foraminifera in Jianchuan,North Jiangsu Province,China

    Institute of Scientific and Technical Information of China (English)

    尤坤元; 张兆干; 吴小根; 施炳文

    2002-01-01

    Through densified surface sampling of foraminifera and accurate elevation measurement along three transect lines in open-coast tidal salt-marsh of Jianchuan, particular salt-marsh foraminifera assemblages were found. The salt-marsh foraminifera assemblages are distributed in well-defined vertical zonations with respect to elevation and closely parallel marsh floral zonations. At the top of the vertical zonation all foraminifera disappear abruptly which are accurately located at the highest high water datum. This distribution pattern can be used to relocate former sea levels accurately (to an accuracy of within ± 5 cm). A modem regional criterion of foraminifera for relocating the former sea levels in high resolution in our country is provided, and deficiencies of studying the vertical zonation only in sheltered coast salt-marsh abroad are filled up.

  17. Early Silurian Foraminifera from Gondwana - an early origin of the multichambered globothalamids?

    Science.gov (United States)

    Kaminski, Michael

    2017-04-01

    Early Silurian foraminifera until now have been regarded to consist of simple single-chambered monothalamids and two-chambered tubothalamids with an agglutinated wall. Although pseudo-multichambered agglutinated foraminifera first appeared in the mid-Ordovician (Kaminski et al. 2009), the origin of true multichambered forms was not believed to have taken place until the early or middle Devonian at the earliest (Holcová, 2002). New discoveries from the Lower Silurian Qusaiba Shale Member in Saudi Arabia point to an earlier origin of the multichambered globothalamid Foraminifera than the currently accepted estimate of 350 Ma (Pawlowski et al. 2003). The agglutinated foraminiferal genera Ammobaculites and Sculptobaculites have been recovered from dark graptolite-bearing claystones of Telychian age, from the transitional facies between the Qusaiba and Sharawa Members of the Qasim Formation at the type locality near Qusaiba town, Saudi Arabia. The multichambered lituolids occur as rare components in a foraminiferal assemblage consisting mostly of monothalamids. This new finding revises our understanding of the early evolution of the multichambered globothalamid foraminifera. The fossil record now shows that the globothalamids were already present in Gondwana by 435 m.y. Holcová, K. 2002. Silurian and Devonian foraminifers and other acid-resistant microfossils from the Barrandian area. Acta Musei Nationalis Pragae, Series B, Historia Naturalis, 58 (3-4), 83-140. Kaminski, M.A., Henderson, A.S., Cetean, C.G. & Waskowska-Oliwa, A. 2009. A new family of agglutinated foraminifera: the Ammolagenidae n.fam., and the evolution of multichambered tests. Micropaleontology, 55 (5), 487-494. Pawlowski, J., Holzmann, M., Berney, C., Fahrni, J.F., Gooday, Aj., Cedhagen, T., Habura, A., & Bowser, SS. 2003. The evolution of early Foraminifera. Proceedings of the National Academy of Sciences, 100 (20), 11494-11498

  18. A new Symbiodinium clade (Dinophyceae) from soritid foraminifera in Hawai'i.

    Science.gov (United States)

    Pochon, Xavier; Gates, Ruth D

    2010-07-01

    Dinoflagellates in the genus Symbiodinium are crucial components of coral reef ecosystems in their roles as endosymbionts of corals and other marine invertebrates. The genus Symbiodinium encompasses eight lineages (clades A-H), and multiple sub-clade types. Symbiodinium in clades A, B, C, and D are most commonly associated with metazoan hosts while clades C, D, F, G, and H with large soritid foraminifera. Recent studies have described a diversity of new Symbiodinium types within each clades, but no new clades have been reported since 2001. Here, we describe a new clade of Symbiodinium isolated from soritid foraminifera from Hawai'i. Published by Elsevier Inc.

  19. Foraminifera as bioindicators in coral reef assessment and monitoring: the FORAM Index. Foraminifera in Reef Assessment and Monitoring.

    Science.gov (United States)

    Hallock, Pamela; Lidz, Barbara H; Cockey-Burkhard, Elizabeth M; Donnelly, Kelly B

    2003-01-01

    Coral reef communities are threatened worldwide. Resource managers urgently need indicators of the biological condition of reef environments that can relate data acquired through remote-sensing, water-quality and benthic-community monitoring to stress responses in reef organisms. The "FORAM" (Foraminifera in Reef Assessment and Monitoring) Index (FI) is based on 30 years of research on reef sediments and reef-dwelling larger foraminifers. These shelled protists are ideal indicator organisms because: Foraminifers are widely used as environmental and paleoenvironmental indicators in many contexts. Reef-building, zooxanthellate corals and foraminifers with algal symbionts have similar water-quality requirements. The relatively short life spans of foraminifers as compared with long-lived colonial corals facilitate differentiation between long-term water-quality decline and episodic stress events. Foraminifers are relatively small and abundant, permitting statistically significant sample sizes to be collected quickly and relatively inexpensively, ideally as a component of comprehensive monitoring programs; and, collection of foraminifers has minimal impact on reef resources. USEPA guidelines for ecological indicators are used to evaluate the Fl. Data required are foraminiferal assemblages from surface sediments of reef-associated environments. The Fl provides resource managers with a simple procedure for determining the suitability of benthic environments for communities dominated by algal symbiotic organisms. The FI can be applied independently, or incorporated into existing or planned monitoring efforts. The simple calculations require limited computer capabilities and therefore can be applied readily to reef-associated environments worldwide. In addition, the foraminiferal shells collected can be subjected to morphometric and geochemical analyses in areas of suspected heavy-metal pollution, and the data sets for the index can be used with other monitoring data in

  20. Effect of carbonate ion concentration and irradiance on calcification in planktonic foraminifera

    DEFF Research Database (Denmark)

    Lombard, Fabien; da Rocha, R. E.; Bijma, J.

    2010-01-01

    rates of these two species are projected to be 6 to 13% lower than the present conditions, while the final shell weights are reduced by 20 to 27% for O. universa and by 4 to 6% for G. sacculifer. These results indicate that ocean acidification would impact on calcite production by foraminifera and may...

  1. Ecology and distribution of recent planktonic foraminifera in eastern part of Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Kutty, M.K.

    (0-200 m) than in the surface (0-10 m) tows. Further, latitudinal gradient of some species which have a definite bearing on hydrography of the sea, has been outlined. Relative production of planktonic foraminifera shows that it is high in the southern...

  2. Tracing shifts of oceanic fronts using the cryptic diversity of the planktonic foraminifera Globorotalia inflata

    Science.gov (United States)

    Morard, Raphaël.; Reinelt, Melanie; Chiessi, Cristiano M.; Groeneveld, Jeroen; Kucera, Michal

    2016-09-01

    The use of planktonic foraminifera in paleoceanographic studies relies on the assumption that morphospecies represent biological species with ecological preferences that are stable through time and space. However, genetic surveys unveiled a considerable level of diversity in most morphospecies of planktonic foraminifera. This diversity is significant for paleoceanographic applications because cryptic species were shown to display distinct ecological preferences that could potentially help refine paleoceanographic proxies. Subtle morphological differences between cryptic species of planktonic foraminifera have been reported, but so far, their applicability within paleoceanographic studies remains largely unexplored. Here we show how information on genetic diversity can be transferred to paleoceanography using Globorotalia inflata as a case study. The two cryptic species of G. inflata are separated by the Brazil-Malvinas Confluence (BMC), a major oceanographic feature in the South Atlantic. Based on this observation, we developed a morphological model of cryptic species detection in core top material. The application of the cryptic species detection model to Holocene samples implies latitudinal oscillations in the position of the confluence that are largely consistent with reconstructions obtained from stable isotope data. We show that the occurrence of cryptic species in G. inflata can be detected in the fossil record and used to trace the migration of the BMC. Since a similar degree of morphological separation as in G. inflata has been reported from other species of planktonic foraminifera, the approach presented in this study can potentially yield a wealth of new paleoceanographical proxies.

  3. Northeast Atlantic Late Quaternary planktic Foraminifera as primary productivity and water mass indicators

    NARCIS (Netherlands)

    Kreveld, van S.A.

    1996-01-01

    Primary productivity and water mass reconstructions based on planktic Foraminifera reveal distinct interglacial/glacial variations for the past 208 ka in a mid-latitude Northeast Atlantic piston core. Average total planktic foraminiferal absolute frequencies and accumulation rates, which are

  4. Foraminifera as climatic indicators in the sediments of Western Indian continental shelf

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    to tell, which can be unravelled by careful analysis and interpretation. Foraminifera are primarily of two kinds-planktonic and benthonic-each having a significant role to play. Therefore, in the study of a sample, the planktonic and benthonic populations...

  5. Recent foraminifera along west coast of India: Restrospect, perspect and prospect

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.

    An immense quantum of work on foraminifera is being carried out in Indian waters by various research centers and universities. However, a thorough review of the foraminiferal studies from Indian waters is yet to be amde. A critical review will also...

  6. Abnormal test growth in benthic foraminifera from hypersaline coastal ponds of the United Arab Emirates

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2014-05-01

    The living (Rose-Bengal stained) benthic foraminifera assemblage from shallow coastal ponds located in the intertidal area of the United Arab Emirate Western Region was investigated. The studied coastal ponds are located between a lagoonal area, characterized by carbonate sedimentation, and the supratidal, evaporite-dominated, sabkha. Sampling was undertaken when the maximum water depth in the ponds was 50 cm with a water temperature ranging from 27 to 35°C, a pH of 8 and a maximum salinity of 60 ppt. The sides and floor of the pond were characterized by a microbial mat. Detached blades of sea grass were present in the ponds and are inferred to have been transported into the pond either during high-tides or storm surges. Collected samples were stained with Rose-Bengal at the moment of sample collection and the living assemblage was studied. The benthic foraminifera that were present show a low-diversity assemblage. Epiphytic larger benthic foraminifera dominate the living assemblage with Peneroplis pertusus and P. planatus characterizing 90% of the living assemblage and the species Spirolina areatina, S. aciculata, Sorites marginalis and Quinqueloculina spp. comprising the rest of the foraminifera community. High percentages (up to 50% of the stained assemblage) of anomalous tests of benthic foraminifera belonging to the genera Peneroplis, Spirolina and Sorites were observed. The anomalies included dissolution, microboring and abnormality in growth. Three different forms of abnormal shell architecture were recorded; the presence of multiple apertures with reduced size, deformation in the general shape of the test and abnormal coiling. The high percentage of abnormal tests reflects natural environmental stress caused by instability of physical parameters (particularly high and variable salinity and temperature) in this kind of transitional marine environment. The unique presence of epiphytic species, suggests that epiphytic foraminifera may be transported into the

  7. Potential importance of physiologically diverse benthic foraminifera in sedimentary nitrate storage and respiration

    Science.gov (United States)

    Bernhard, Joan M.; Casciotti, Karen L.; McIlvin, Matthew R.; Beaudoin, David J.; Visscher, Pieter T.; Edgcomb, Virginia P.

    2012-09-01

    Until recently, the process of denitrification (conversion of nitrate or nitrite to gaseous products) was thought to be performed exclusively by prokaryotes and fungi. The finding that foraminifera perform complete denitrification could impact our understanding of nitrate removal in sediments as well as our understanding of eukaryotic respiration, especially if it is widespread. However, details of this process and the subcellular location of these reactions in foraminifera remain uncertain. For example, prokaryotic endobionts, rather than the foraminifer proper, could perform denitrification, as has been shown recently in an allogromiid foraminifer. Here, intracellular nitrate concentrations and isotope ratios (δ15NNO3 and δ18ONO3) were measured to assess the nitrate dynamics in four benthic foraminiferal species (Bolivina argentea, Buliminella tenuata, Fursenkoina cornuta, Nonionella stella) with differing cellular architecture and associations with microbial endobionts, recovered from Santa Barbara Basin, California. Cellular nitrate concentrations were high (12-217 mM) in each species, and intracellular nitrate often had elevated δ15NNO3 and δ18ONO3 values. Experiments including suboxic and anoxic incubations of B. argentea revealed a decrease in intracellular nitrate concentration and an increase in δ15NNO3 and δ18ONO3over time, indicating nitrate respiration and/or denitrification within the foraminifera. Results illustrate that nitrate reduction occurs in a range of foraminiferal species, including some possessing endobionts (including a chloroplast-sequestering species) and others lacking endobionts, implying that microbial associates may not solely be responsible for this process in foraminifera. Furthermore, we show that benthic foraminifera may represent important reservoirs of nitrate storage in sediments, as well as mediators of its removal.

  8. Distribution, factor analysis and ecology of benthic foraminifera within inner shelf regime of Vengurla-Bhatkal sector, West Coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    One hundred and two taxa of benthic foraminifera are reported from the neritic environment (15-60 m) of Vengurla - Bhatkal area. Q-mode factor analysis reveals 6 important foraminiferal assemblages accounting for 92% of the information given...

  9. Distribution of planktonic foraminifera in waters of the submarine coral banks in southeast Arabian Sea during winter

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Balasubramanian, T.

    Twentyfive species of planktonic foraminifera are recorded from 36 plankton tows collected from waters of the submerged coral banks- Bassas de Pedro, Sesostris and Cora Divh-located at northern end of the Laccadive group of islands in southeastern...

  10. Taxonomy and distribution of benthic foraminifera from the sediments of Palk Strait, Tamil Nadu, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Gandhi, S.; Rajamanickam, G.V.; Nigam, R.

    A systematic study of benthic foraminifera has been made on 42 sediment samples collected between Mandapam and Kodiyakkarai, off Palk Strait, Tamil Nadu, India. A total of 102 benthic foraminiferal species belonging to 52 genera, 38 families, 23...

  11. Eocene seasonality and seawater alkaline earth reconstruction using shallow-dwelling large benthic foraminifera

    Science.gov (United States)

    Evans, David; Müller, Wolfgang; Oron, Shai; Renema, Willem

    2013-11-01

    Intra-test variability in Mg/Ca and other (trace) elements within large benthic foraminifera (LBF) of the family Nummulitidae have been investigated using laser-ablation inductively-coupled plasma mass spectrometry (LA-ICPMS). These foraminifera have a longevity and size facilitating seasonal proxy retrieval and a depth distribution similar to 'surface-dwelling' planktic foraminifera. Coupled with their abundance in climatically important periods such as the Paleogene, this means that this family of foraminifera are an important but under-utilised source of palaeoclimatic information. We have calibrated the relationship between Mg/Ca and temperature in modern Operculina ammonoides and observe a ˜2% increase in Mg/Ca °C-1. O. ammonoides is the nearest living relative of the abundant Eocene genus Nummulites, enabling us to reconstruct mid-Eocene tropical sea surface temperature seasonality by applying our calibration to fossil Nummulites djokdjokartae from Java. Our results indicate a 5-6 °C annual temperature range, implying greater than modern seasonality in the mid-Eocene (Bartonian). This is consistent with seasonal surface ocean cooling facilitated by enhanced Eocene tropical cyclone-induced upper ocean mixing, as suggested by recent modelling results. Analyses of fossil N. djokdjokartae and Operculina sp. from the same stratigraphic interval demonstrate that environmental controls on proxy distribution coefficients are the same for these two genera, within error. Using previously published test-seawater alkaline earth metal distribution coefficients derived from an LBF of the same family (Raitzsch et al., 2010) and inorganic calcite, with appropriate correction systematics for secular Mg/Casw variation (Evans and Müller, 2012), we use our fossil data to produce a more accurate foraminifera-based Mg/Casw reconstruction and an estimate of seawater Sr/Ca. We demonstrate that mid-Eocene Mg/Casw was ≲2 molmol, which is in contrast to the model most

  12. Foraminifera and the ecology of sea grass communities since the late Cretaceous

    Science.gov (United States)

    Hart, Malcolm; Smart, Christopher; Jagt, John

    2016-04-01

    Sea grasses are marine angiosperms (plants) that, in the late Cretaceous, migrated from the land into shallow-water marine environments. They represent a distinct, but fragile, marine habitat and sea grass meadows are often regarded as biodiversity hot-spots with a range of species (including fish, sea horses and cuttlefish) using them as nurseries for their young. Foraminifera are often found associated with sea grass meadows, with the associated taxa reflecting both the environment and palaeolatitude. In the tropics and sub-tropics, miliolid foraminifera dominate (e.g., Peneroplis spp.) as do large discoidal taxa such as Marginopora and Calcarina. In temperate to cool latitudes the assemblage changes to one dominated by smaller benthic taxa, including Elphidium spp. One taxon, Elphidium crispum, is geotropic and is often found - in the summer months - to crowd the fronds of the sea grass. In the Gulpen and Maastricht formations of the Maastricht area (The Netherlands and Belgium) sea grass fossils (both fronds and rhizomes) have been recorded in association with assemblages of both larger and smaller benthic foraminifera (Hart et al., 2016). Some of the large discoidal forms (e.g., Omphalocyclus and Orbitoides/Lepidorbitoides) and the distinctive Siderolites are associated with these sea grass fossils and are suggestive of the modern sea grass communities of sub-tropical areas. While earlier records were of relatively isolated sea grasses, in September/October 2015 surfaces with abundant sea grasses were found that are suggestive of complete 'meadows'. Preservation of some silicified rhizomes indicates that silicification must have been very rapid, before any degradation or compaction of the delicate tissues. The presence of sea grass fossils and their associated benthic foraminifera is indicative of a clear, shallow-water seaway, with a maximum depth of 15-20 m. The reported variations in sea level during the latest Cretaceous cannot, therefore, have been very

  13. Distribution of living larger benthic foraminifera in littoral environments of the United Arab Emirates

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2015-04-01

    The distribution of larger benthic foraminifera in Recent littoral environment of the United Arab Emirates (Abu Dhabi and Western regions) was investigated with the aim of understanding the response of those foraminifera to an increase in water salinity. For this purpose, 100 sediment samples from nearshore shelf, beach-front, channel, lagoon, and intertidal environment were collected. Sampling was undertaken at a water depth shallower than 15 m in water with a temperature of 22 to 35˚C, a salinity ranging from 40 to 60‰ and a pH of 8. Samples were stained with rose Bengal at the moment of sample collection in order to identify living specimens. The most abundant epiphytic larger benthic foraminifera in the studied area were Peneroplis pertusus and P. planatus with less common Spirolina areatina, S. aciculate and Sorites marginalis. The living specimens of the above mentioned species with normal test growing were particularly abundant in the nearshore shelf and lagoonal samples collected on seaweed. Dead specimens were concentrated in the coarser sediments of the beach-front, probably transported from nearby environments. Shallow coastal ponds are located in the upper intertidal zone and have a maximum salinity of 60‰ and contain abundant detached seagrass. Samples collected from these ponds possess a living foraminifera assemblage dominated by Peneroplis pertusus and P. planatus. High percentages (up to 50% of the stained assemblage) of Peneroplis presented abnormality in test growth, such as the presence of multiple apertures with reduced size, deformation in the general shape of the test, irregular suture lines and abnormal coiling. The high percentage of abnormal tests reflects natural environmental stress mainly caused by high and variable salinity. The unique presence of living epiphytic species, suggests that epiphytic foraminifera may be transported into the pond together with seagrass and continued to live in the pond. This hypothesis is supported by

  14. Calcification intensity in planktonic Foraminifera reflects ambient conditions irrespective of environmental stress

    Directory of Open Access Journals (Sweden)

    M. F. G. Weinkauf

    2013-07-01

    Full Text Available Planktonic Foraminifera are important marine calcifiers, and the ongoing change in the oceanic carbon system makes it essential to understand the influence of environmental factors on the biomineralisation of their shells. The amount of calcite deposited by planktonic Foraminifera during calcification has been hypothesized to reflect a range of environmental factors. However, it has never been assessed whether their calcification only passively responds to the conditions of the ambient seawater or whether it reflects changes in resource allocation due to physiological stress. To disentangle these two end-member scenarios, an experiment is required where the two processes are separated. A natural analogue to such an experiment occurred during the deposition of the Mediterranean sapropels, where large changes in surface water composition and stratification at the onset of the sapropel deposition were decoupled from local extinctions of planktonic Foraminifera species. We take advantage of this natural experiment and investigate the reaction of calcification intensity, expressed as size-normalized weight (SNW, of four species of planktonic Foraminifera to changing conditions during the onset of Sapropel S5 (126–121 ka in a sediment core from the Levantine Basin. We observe a significant relationship between SNW and surface water properties, as reflected by stable isotopes in the calcite of Foraminifera shells, but we failed to observe any reaction of calcification intensity on ecological stress during times of decreasing abundance culminating in local extinction. The reaction of calcification intensity to surface water perturbation at the onset of the sapropel was observed only in surface dwelling species, but all species calcified more strongly prior to the sapropel deposition and less strongly within the sapropel than at comparable conditions during the present day. These results indicate that the high-salinity environment of the glacial

  15. Allostaffia, a new genus name for Staffia Heinrich, 1999 (Allotheria, Haramiyida preoccupied by Staffia Schubert, 1911 (Protista, Foraminifera

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    W.-D. Heinrich

    2004-01-01

    Full Text Available The genus name Staffia Heinrich, 1999 published for a Jurassic allotherian mammal from Tendaguru, Tanzania, is preoccupied by Staffia Schubert, 1911 (Protista, Foraminifera. A replacement name, Allostaffia, is proposed here. Der Gattungsname Staffia Heinrich, 1999, der für einen Haramiyiden (Mammalia, Allotheria aus dem Oberjura von Tendaguru, Tansania (Ostafrika vergeben wurde, ist durch Staffia Schubert, 1911 (Protista, Foraminifera präokkupiert. Er wird daher durch den neuen Namen Allostaffia ersetzt. doi:10.1002/mmng.20040070108

  16. Live (Rose-bengal stained) foraminifera from deep-sea anoxic salt brine in the Eastern Mediterranean: toward understanding limit of life for single-celled eukaryotes (foraminifera)

    Science.gov (United States)

    Kitazato, H.; Ohkawara, N.; Iwasaki, A.; Nomaki, H.; Akoumianaki, I.; Tokuyama, H.

    2012-04-01

    What is a limit of life for the eukaryotes? Eukaryotes are thought to adapt and evolve under oxic environmental conditions. Recently, there are many exceptions for this hypothesis, as many eukaryotes including metazoan groups are found in anoxic environmental conditions. We found many rose-bengal stained foraminifera from a deep-hypersaline anoxic basin (DHAB) in the eastern Mediterranean. During KH06-04 cruise, we conducted oceanographic research at Medée Lake, the largest DHAB, that is located 100km southwest of Crete Island in the eastern Mediterranean. The lake situates at 2920m in water depth. Depth of saline water is 120m in maximum. Both water and sediment samplings were carried out both with Niskin bottles and multiple corer attached to camera watching sampling system at three sites, inside of the lake (CS), the edge of the lake (OMS) and the normal deep-sea floor (RS). Temperature, salinity, and dissolved oxygen concentrations at central saline lake are 15.27 oC, 328PSU, and 0.0 ml/L, respectively. Strong smell of hydrogen sulfide was detected from the lake sediment. Subsamples were conducted for multiple core samples using 3 subcores(φ 2.9cm) from each core tube (φ 8.2cm). Sediment samples were fixed with 4% formalin Rose Bengal solution on board. In laboratory, samples were washed with 32μm sieve. Rose Bengal stained specimens were picked under binocular stereomicroscope (Zeiss Stemi SV11) for surface 0.5cm layer, and identified with inverted microscope (Nikon ECLIPSE TE300). In total, 26 species belonging to 9 genera were identified from three sites. Six species belonging to two genera were identified in the center of the salt brine. Only a few species are common among three sites, even though the numbers of common species were 10 between OMS and RS sites. In DHAB, spherical organic-walled species, such as allogromiid and psammosphaerid, are dominant. In contrast, tube-like chitinous foraminifera, such as Resigella, Conicotheca and Nodellum, are

  17. Syn-ecological study of benthic foraminifera of the Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Hiltermann, H.

    1987-01-01

    The ecological-biosociological analysis of 170 secies of benthic foraminifera obtained from 87 bottom sediment samples of the Gulf of Mexico (Depth range 152 to 3515 m) as presented by Pflum and Frerichs 1976 allows the distinction of 8 different biocenoses. Each of these biocenotic units is characterized by its own specific parameters. One of those, the temperatur, appears to be important for the ecology. The average specimen-number decreases with increasing water depth down to 10.4% of the number observed in shallower water. The agglutinated foraminifera have the highest occurrence of specimens between 710 and 1980 m. In 2 of the 8 units species were observed which are foreign to the biotops.

  18. Recent benthic foraminifera and sedimentary facies distribution of the Abu Dhabi (United Arab Emirates) coastline

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2014-05-01

    The distribution of benthic foraminifera and sedimentary facies from Recent coastline environments adjacent to the coastline of Abu Dhabi (UAE) was studied in detail with the aim to: 1) provide reliable analogs for understanding and interpreting the depositional environment of ancient shallow-marine sediments from the UAE; 2) assess any modifications in the distribution of benthic environments and sedimentary facies in an area affected by significant anthropogenic activities - particular construction and land reclamation. A total of 100 sea-floor sediment samples were collected in different shallow-marine sedimentary environments (nearshore shelf, beach-front, channels, ooid shoals, lagoon and mangals) close to the coastline of Abu Dhabi Island. Where possible, we revisited the sampling sites used in several studies conducted in the middle of last century (prior to any significant anthropogenic activities) to assess temporal changes in Recent benthic foraminifera and sedimentary facies distribution during the last 50 years. Five foraminiferal assemblages were recognized in the studied area. Species with a porcellaneous test mainly belonging to the genera Quinqueloculina, Triloculina, Spiroloculina, Sigmoilinita are common in all studied areas. Larger benthic foraminifera Peneroplis and Spirolina are particularly abundant in samples collected on seaweed. Hyaline foraminifera mostly belonging to the genera Elphidium, Ammonia, Bolivina and Rosalina are also common together with Miliolidae in the nearshore shelf and beach front. Agglutinated foraminifera (Clavulina, Textularia, Ammobaculites and Reophax) are present in low percentages. The species belonging to the genera Ammobaculites and Reophax are present only in the finest grain samples particularly in lagoons and mangal environments and have not been reported previously in the studied area. The majority of the ooid shoal sediments, the coarser sediments of the beach-front and samples collected in dredged channels

  19. Exploring the controls on element ratios in middle Eocene samples of the benthic foraminifera Oridorsalis umbonatus

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    C. F. Dawber

    2012-12-01

    Full Text Available Culturing studies and empirically based core top calibrations have been used to infer that elemental ratios in benthic foraminifera can be used as proxies to reconstruct past variations in bottom water temperature and saturation state (Δ [CO32−]. However the mechanisms linking elemental ratios to these parameters are poorly constrained. Here, we explore the environmental parameters influencing the incorporation of B, Li, Sr and Mg in Oridorsalis umbonatus in early Cenozoic sediments from Ocean Drilling Program Site 1209. We investigate the influence of middle Eocene variations in intermediate water Δ [CO32−] using relationships developed from core top samples. The fidelity of bottom water Δ[CO32−] reconstructions based on single element ratios is assessed by comparing the X/Ca-based reconstructions to each other and to carbon cycle proxy records (benthic foraminifera δ13C, organic carbon content, foraminifera dissolution indices, and a seawater δ18O reconstruction for Site 1209. Discrepancies in the reconstructed Δ[CO32−] values based on these different metal ratios suggest that there are still gaps in our understanding of the parameters influencing X/Ca and demonstrate that caution is required when interpreting palaeo-reconstructions that are derived from a single elemental ratio. The downcore record of O. umbonatus Mg/Ca does not exhibit any similarities with the Li/Ca, B/Ca and Sr/Ca records, suggesting that the environmental parameters influencing Mg/Ca may be different for this species, consistent with temperature as the strongest control on this elemental ratio. This hypothesis is supported by the coefficients of multiple linear regression models on published Mg/Ca data. An incomplete understanding of the controls on elemental incorporation into benthic foraminifera hinders our ability to confidently quantify changes in saturation state using single X/Ca reconstructions over a range of timescales.

  20. A note on the laboratory culture of benthic foraminifera collected from nearshore region off Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.; Koli, N.Y.

    of benthic foraminifera was carried out in two phases. In phase 1 we used living organisms collected from the field as parent to be cultured under laboratory conditions using filtered sea water as media. This attempt was made to obtain the offsprings... responded to culture. (2) Food has conducive effect (3) The formation of initial chambers took less time as compared to latter chambers. Fig. 1 shows the growth of successive chambers. However, some of the parents reproduced at varying intervals...

  1. Benthic foraminifera as indicators of habitat in a Mediterranean delta: implications for ecological and palaeoenvironmental studies

    Science.gov (United States)

    Benito, Xavier; Trobajo, Rosa; Cearreta, Alejandro; Ibáñez, Carles

    2016-10-01

    The ecology and modern distribution of benthic foraminiferal assemblages were analysed in the Ebro Delta (NW Mediterranean Sea). Foraminiferal distributions were from 191 sediment surface samples covering a wide range of deltaic habitats and adjacent open sea areas. According to similarity in species composition, cluster analysis identified four habitat types: (1) offshore habitat, (2) nearshore and outer bays, (3) salt and brackish marshes and (4) coastal lagoons and inner bays. Canonical Correspondence Analysis identified water depth, salinity and sand content as the main environmental factors structuring living foraminiferal assemblages. Partial Canonical Correspondence Analysis revealed water depth as the most statistically significant associated with the distribution of modern foraminifera in the Ebro Delta. Thus, a transfer function for water depth using Weighted Average Partial Least Squares regression was successfully developed. Although depth per se is unlikely to affect the foraminifera directly but will exert its effects via various environmental variables that co-vary with depth in the deltaic habitats (e.g. hydrodynamics, oxygen, food availability, etc), the resulting model (r2 = 0.89; RMSEP = 0.32 log10 m) suggested a strong correlation between observed and foraminifera-predicted water depths, and therefore provided a potentially useful tool for water-depth reconstructions in the Ebro Delta. This work indicated the potential role of modern foraminifera as quantitative indicators of water depth and habitat types in the Ebro Delta. This complementary approach (transfer function and indicator species) will allow reconstruction of the palaeoenvironmental changes that have occurred in the Ebro Delta based on the benthic foraminiferal record.

  2. Miocene deep water agglutinated foraminifera from Viosca Knoll, offshore Louisiana (Gulf of Mexico)

    OpenAIRE

    Green, R C; Kaminski, M.A.; Sikora, P. J.

    2004-01-01

    An exploration well from the Gulf of Mexico, Amoco Viosca Knoll-915, has been studied in order to document the Neogene foraminiferal assemblages. Ditch cuttings samples from the Amoco V.K. 915 well yielded diverse assemblages of agglutinated and calcareous benthic foraminifera over a stratigraphic interval of 2940 m. Three species associations can be identified in the studied interval; the stratigraphical location of these associations is evident when total agglutinated species...

  3. Relationship between abundance and morphology of benthic foraminifera Epistominella exigua: Palaeoclimatic implications

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Deopujari, A.; Nigam, R.; Henriques, P.J.

    ) as tools in deep-water palaeoceanography: Environmental influences on faunal characteristics. Advan. Mar. Biol. 46, 1-90. Gupta, A.K., Thomas, E., 2003. Initiation of Northern Hemisphere glaciation and strengthening of the northeast Indian monsoon: Ocean.../Plenum Publishers, pp. 195-216. Nigam, R., 1986. Dimorphic forms of Recent foraminifera: An additional tool in palaeoclimatic studies. Paleoecol. Palaeogeogra. Palaeloclimatol. 53, 239-244. Nigam, R., Khare, N., 1992. The reciprocity between coiling direction...

  4. Appraisal of laboratory culture experiments on benthic foraminifera to assess/develop paleoceanographic proxies

    Digital Repository Service at National Institute of Oceanography (India)

    Linshy, V.N.; Rana, S.S.; Kurtarkar, S.; Saraswat, R.; Nigam, R.

    through ages Though laboratory maintenance of benthic foraminifera started from the first half of the 19 th century and number of studies were published during the later half of the 19 th century, it was not until the mid of 20 th century... structure analysis. ms et al. 91 1981 Identified significant disequilibrium in carbon and oxygen isotopic fractionation in Heterostegina depressa and attributed it to the vital effects that varied with changing light intensity and age. y 139...

  5. Quantitative paleobathymetry using oxygen isotopes and shape changes in benthic foraminifera

    Energy Technology Data Exchange (ETDEWEB)

    Gary, A.C.; Williams, D.F.; Healy-Williams, N.

    1987-05-01

    Accurate estimates of paleodepth are of critical importance to oil exploration in determining environment of deposition and geologic history. Models based on the test shape and the /sup 18/O//sup 16/O ratio in benthic foraminifera from the northwestern Gulf of Mexico indicate that a resolution of +/- 75 ft can be achieved in paleobathymetric reconstructions. The proportion of /sup 18/O and /sup 16/O incorporated into the tests of benthic foraminifera varies with bottom water temperature in a predictable manner. This depth/temperature relationship is the result of the temperature dependence of oxygen isotopic fractionation between sea water and calcium carbonate, and it allows the tests of benthic foraminifera to be used as indicators of paleotemperature. Since subbottom water temperatures on the outer shelf and slope decrease systematically with increasing water depth, these paleotemperatures can be used to reconstruct paleobathymetric trends. Paleobathymetric interpretations can also be independently inferred from Fourier shape analysis of benthic foraminiferal species. Combining the oxygen isotope and shape relationships relative to water depth increases the resolution of paleobathymetric reconstructions and provides an independent check on interpretations based on faunal assemblages and sedimentological data. These paleodepth models should allow extinct taxa to be used for paleobathymetric reconstructions as well.

  6. Benthic foraminifera for environmental monitoring: a case study in the central Adriatic continental shelf.

    Science.gov (United States)

    Capotondi, L; Bergami, C; Orsini, G; Ravaioli, M; Colantoni, P; Galeotti, S

    2015-04-01

    A study of benthic foraminifera was carried out in sediment samples collected from the central Adriatic coast of Italy, near the Ancona harbour and the Falconara Marittima oil refinery, in order to validate and support their use as bioindicators of ecosystem quality. On the basis of a principal component analysis (PCA), three biotopes (following the bathymetric gradient) have been documented, showing that the distribution pattern of benthic foraminifera is principally related to riverine inputs, organic matter contents at the seafloor, and sediment grain size. We observed higher abundances of opportunistic, low-oxygen tolerant taxa along the coastline, thus being representative of polluted environmental conditions. Near the Falconara Marittima oil refinery, the microfaunal assemblages is characterized by the absence of living specimens and by a low diversity associated with the dominance of opportunistic species. At this site, aberrant tests were also found. The data point out that Ammonia parkinsoniana and Quinqueloculina seem to be the most sensitive taxa and can be considered as good bioindicators of environmental stress in this area. This study confirms that faunal composition and morphology of benthic foraminifera respond to human-induced environmental perturbations, making their study potentially useful for biomonitoring in coastal-marine areas.

  7. Planktonic foraminifera-derived environmental DNA extracted from abyssal sediments preserves patterns of plankton macroecology

    Directory of Open Access Journals (Sweden)

    R. Morard

    2017-06-01

    Full Text Available Deep-sea sediments constitute a unique archive of ocean change, fueled by a permanent rain of mineral and organic remains from the surface ocean. Until now, paleo-ecological analyses of this archive have been mostly based on information from taxa leaving fossils. In theory, environmental DNA (eDNA in the sediment has the potential to provide information on non-fossilized taxa, allowing more comprehensive interpretations of the fossil record. Yet, the process controlling the transport and deposition of eDNA onto the sediment and the extent to which it preserves the features of past oceanic biota remains unknown. Planktonic foraminifera are the ideal taxa to allow an assessment of the eDNA signal modification during deposition because their fossils are well preserved in the sediment and their morphological taxonomy is documented by DNA barcodes. Specifically, we re-analyze foraminiferal-specific metabarcodes from 31 deep-sea sediment samples, which were shown to contain a small fraction of sequences from planktonic foraminifera. We confirm that the largest portion of the metabarcode originates from benthic bottom-dwelling foraminifera, representing the in situ community, but a small portion (< 10 % of the metabarcodes can be unambiguously assigned to planktonic taxa. These organisms live exclusively in the surface ocean and the recovered barcodes thus represent an allochthonous component deposited with the rain of organic remains from the surface ocean. We take advantage of the planktonic foraminifera portion of the metabarcodes to establish to what extent the structure of the surface ocean biota is preserved in sedimentary eDNA. We show that planktonic foraminifera DNA is preserved in a range of marine sediment types, the composition of the recovered eDNA metabarcode is replicable and that both the similarity structure and the diversity pattern are preserved. Our results suggest that sedimentary eDNA could preserve the ecological structure of

  8. The role of benthic foraminifera in the benthic nitrogen cycle of the Peruvian oxygen minimum zone

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    N. Glock

    2013-07-01

    Full Text Available The discovery that foraminifera are able to use nitrate instead of oxygen as an electron acceptor for respiration has challenged our understanding of nitrogen cycling in the ocean. It was thought before that only prokaryotes and some fungi are able to denitrify. Rate estimates of foraminiferal denitrification have been very sparse and limited to specific regions in the oceans, not comparing stations along a transect of a certain region. Here, we present estimates of benthic foraminiferal denitrification rates from six stations at intermediate water depths in and below the Peruvian oxygen minimum zone (OMZ. Foraminiferal denitrification rates were calculated from abundance and assemblage composition of the total living fauna in both surface and subsurface sediments, as well as from individual species specific denitrification rates. A comparison with total benthic denitrification rates as inferred by biogeochemical models revealed that benthic foraminifera probably account for the total denitrification in shelf sediments between 80 and 250 m water depth. The estimations also imply that foraminifera are still important denitrifiers in the centre of the OMZ around 320 m (29–50% of the benthic denitrification, but play only a minor role at the lower OMZ boundary and below the OMZ between 465 and 700 m (2–6% of total benthic denitrification. Furthermore, foraminiferal denitrification has been compared to the total benthic nitrate loss measured during benthic chamber experiments. The estimated foraminiferal denitrification rates contribute 2 to 46% to the total nitrate loss across a depth transect from 80 to 700 m, respectively. Flux rate estimates range from 0.01 to 1.3 mmol m−2 d−1. Furthermore we show that the amount of nitrate stored in living benthic foraminifera (3 to 3955 μmol L−1 can be higher by three orders of magnitude as compared to the ambient pore waters in near-surface sediments sustaining an important nitrate reservoir in

  9. Distribution of Foraminifera in the Core Samples of Kollidam and Marakanam Mangrove Locations, Tamil Nadu, Southeast Coast of India

    Science.gov (United States)

    Nowshath, M.

    2013-05-01

    In order to study the distribution of Foraminifera in the subsurface sediments of mangrove environment, two core samples have been collected i) near boating house, Pitchavaram, from Kollidam estuary (C2) and ii) backwaters of Marakanam (C2)with the help of PVC corer. The length of the core varies from a total of 25 samples from both cores were obtained and they were subjected to standard micropaleontological and sedimentological analyses for the evaluation of different sediment characteristics. The core sample No.C1 (Pitchavaram) yielded only foraminifera whereas the other one core no.C2 (Marakanam) has yielded discussed only the down core distribution of foraminifera. The widely utilized classification proposed by Loeblich and Tappan (1987) has been followed in the present study for Foraminiferal taxonomy and accordingly 23 foraminiferal species belonging to 18 genera, 10 families, 8 superfamilies and 4 suborders have been reported and illustrated. The foraminiferal species recorded are characteristic of shallow innershelf to marginal marine and tropical in nature. Sedimentological parameters such as CaCO3, Organic matter and sand-silt-clay ratio was estimated and their down core distribution is discussed. An attempt has been made to evaluate the favourable substrate for the Foraminifera population abundance in the present area of study. From the overall distribution of foraminifera in different samples of Kollidam estuary (Pitchavaram area), and Marakanam estuary it is observed that siltysand and sandysilt are more accommodative substrate for the population of foraminifera, respectively. The distribution of foraminifera in the core samples indicate that the sediments were deposited under normal oxygenated environment conditions.;

  10. Benthic foraminifera at the Cretaceous-Tertiary boundary around the Gulf of Mexico

    Science.gov (United States)

    Alegret, Laia; Molina, Eustoquio; Thomas, Ellen

    2001-10-01

    Cretaceous-Tertiary (K-T) boundary sections in northeastern Mexico contain marly formations separated by a controversial clastic unit. Benthic foraminifera in seven sections indicate middle and lower bathyal depths of deposition for the marls, with the exception of the upper bathyal northernmost section. Mixed neritic-bathyal faunas were present in the clastic unit, indicating redeposition in the deep basin by mass-wasting processes resulting from the K-T bolide impact in the Gulf of Mexico. Benthic foraminifera in the Mexican sections, and at other deep-sea locations, were not subject to major extinction at the time of impact, but there were temporary changes in assemblage composition. Benthic faunas indicate well- oxygenated bottom waters and mesotrophic conditions during the late Maastrichtian and increased food supply during the latest Maastrichtian. The food supply decreased drastically just after the K-T boundary, possibly because of the collapse of surface productivity. Cretaceous and early Paleogene benthic foraminifera, however, did not exhibit the benthic-pelagic coupling of present-day faunas, as documented by the lack of significant extinction at the K-T collapse of surface productivity. Much of the food supplied to the benthic faunas along this continental margin might have been refractory material transported from land or shallow coastal regions. The decrease in food supply at the K-T boundary might be associated with the processes of mass wasting, which removed surface, food-rich sediment. Benthic faunas show a staggered pattern of faunal recovery in the lowermost Paleogene, consistent with a staged recovery of the vertical organic flux but also with a gradual buildup of organic matter in the sediment.

  11. Projected impacts of climate change and ocean acidification on the global biogeography of planktonic foraminifera

    Directory of Open Access Journals (Sweden)

    T. Roy

    2014-06-01

    Full Text Available Planktonic foraminifera are a major contributor to the deep carbonate-flux and the planktonic biomass of the global ocean. Their microfossil deposits form one of the richest databases for reconstructing paleoenvironments, particularly through changes in their taxonomic and shell composition. Using an empirically-based foraminifer model that incorporates three known major physiological drivers of foraminifer biogeography – temperature, food and light – we investigate (i the global redistribution of planktonic foraminifera under anthropogenic climate change, and (ii the alteration of the carbonate chemistry of foraminifer habitat with ocean acidification. The present-day and future (2090–2100 3-D distributions of foraminifera are simulated using temperature, plankton biomass, and light from an Earth system model forced with historical and a future (IPCC A2 high CO2 emission scenario. The broadscale patterns of present day foraminifer biogeography are well reproduced. Foraminifer abundance and diversity are projected to decrease in the tropics and subpolar regions and increase in the subtropics and around the poles. In the tropics, the geographical shifts are driven by temperature, while the vertical shifts are driven by both temperature and food availability. In the high-latitudes, vertical shifts are driven by food availability, while geographical shifts are driven by both food availability and temperature. Changes in the marine carbon cycle would be expected in response to (i the large-scale rearrangements in foraminifer abundance, and (ii the reduction of the carbonate concentration in the habitat range of planktonic foraminifers: from 10–30 μmol kg−1 in the polar/subpolar regions to 30–70 μmol kg−1 in the subtropical/tropical regions. High-latitude species are most vulnerable to anthropogenic change: their abundance and available habitat decrease and up to 10% of their habitat drops below the calcite saturation horizon.

  12. Planktonic foraminifera-derived environmental DNA extracted from abyssal sediments preserves patterns of plankton macroecology

    Science.gov (United States)

    Morard, Raphaël; Lejzerowicz, Franck; Darling, Kate F.; Lecroq-Bennet, Béatrice; Winther Pedersen, Mikkel; Orlando, Ludovic; Pawlowski, Jan; Mulitza, Stefan; de Vargas, Colomban; Kucera, Michal

    2017-06-01

    Deep-sea sediments constitute a unique archive of ocean change, fueled by a permanent rain of mineral and organic remains from the surface ocean. Until now, paleo-ecological analyses of this archive have been mostly based on information from taxa leaving fossils. In theory, environmental DNA (eDNA) in the sediment has the potential to provide information on non-fossilized taxa, allowing more comprehensive interpretations of the fossil record. Yet, the process controlling the transport and deposition of eDNA onto the sediment and the extent to which it preserves the features of past oceanic biota remains unknown. Planktonic foraminifera are the ideal taxa to allow an assessment of the eDNA signal modification during deposition because their fossils are well preserved in the sediment and their morphological taxonomy is documented by DNA barcodes. Specifically, we re-analyze foraminiferal-specific metabarcodes from 31 deep-sea sediment samples, which were shown to contain a small fraction of sequences from planktonic foraminifera. We confirm that the largest portion of the metabarcode originates from benthic bottom-dwelling foraminifera, representing the in situ community, but a small portion (DNA is preserved in a range of marine sediment types, the composition of the recovered eDNA metabarcode is replicable and that both the similarity structure and the diversity pattern are preserved. Our results suggest that sedimentary eDNA could preserve the ecological structure of the entire pelagic community, including non-fossilized taxa, thus opening new avenues for paleoceanographic and paleoecological studies.

  13. Distribution of Recent Benthic Foraminifera and its Environmental Conditions of Karaikal, Central Coast of Tamil Nadu

    Science.gov (United States)

    Murugan, R.; Gandhi, S.

    2013-05-01

    Foraminifera have been successful inhabitants of every aquatic environment from deep oceans to brackish water lagoons, estuaries and even rarely in freshwater streams, lakes etc. offshore region of Karaikal the present study has been taken up to enhance the existing knowledge on foraminifera of central coast of Tamil Nadu, India. Totally 21 sediment and water samples were collected from the offshore region. The depth of sample collection in offshore area ranges from 1.5 m to 12 m. Standard procedures adopted for the evaluation of different environmental parameters are incorporated. A total of 33 foraminiferal taxa belonging to 17 genera, 12 subfamilies, 14 superfamilies, and 4 suborders have been identified. In Karaikal , the mean size of the sediments on the foreshore ranges from 1.51 to 2.95 φ indicating the predominance of fine sediments (80-85%) with an admixture of medium-grained sands. Calcium carbonate content is generally found to be directly proportional to the population size in both the estuary and shelf area. It clearly indicates that due to the erosional activities whatever sediments deposited near the Arasalar river in that region are transported to the marine region and were drifted towards northern direction by longshore current, hence the deposition of carbonate in the sediments shows negative correlation. Due to strong high energy environment the current action is more in this region the juvinile forms of A. beccarri, A.tepida, A. dendata, E. crispum, P. calar, and P. nipponica only withstand and the other species are absent. The Correlation between Living vs Dead, Dead Vs Calcium carbonate, Salinity Vs living, Organic matter Vs Living, Organic matter Vs Carbonate content shows positive correlation for all the samples like LT, HT, Beach, River, and Offshore. Even though, all the ecological parameters having good correlation with foraminifera, but the distribution are very less in the study area. M.RAJA Dept.of.Geology University of Madras Chennai

  14. Variations in phytodetritus derived carbon uptake of the intertidal foraminifera Ammonia tepida and Haynesina germanica

    Science.gov (United States)

    Wukovits, Julia; Bukenberger, Patrick; Enge, Annekatrin; Wanek, Wolfgang; Watzka, Margarete; Heinz, Petra

    2016-04-01

    Phytodetritus represents a major component of particulate organic carbon in intertidal mudflats. Estuaries and tidal currents yield an extensive amount of these particles that display a substantial nutrient source for littoral food webs. For benthic foraminifera, a group of marine protists, phytodetritus serves as the main food source. Foraminifera are considered to play a significant role in marine carbon turnover processes and show seasonally very high population densities in intertidal sediments. Therefore, it is important to gather explicit data about the specific carbon uptake behavior of intertidal foraminiferal species. In this study, laboratory feeding experiments were carried out to observe phytodetrital carbon uptake of foraminiferal specimen collected in the German Wadden Sea. Artificially produced phytodetritus was labelled with 13C to follow carbon ingestion into foraminiferal cytoplasm over time at different simulated conditions. The experiments were performed with monocultures under exclusion of other meiofauna. Chlorophyte detritus (Dunaliella tertiolecta) was fed to the two common species Ammonia tepida and Haynesina germanica. Ammonia tepida showed a significantly higher affinity to this food source than H. germanica. Testing the effect of temperature revealed a significant decrease of carbon ingestion with increasing temperature in H. germanica. Observations focusing on A. tepida showed a rising phytodetrital carbon content in the biomass of juvenile individuals in contrast to adult foraminifera. In general, carbon uptake reaches saturation levels a few hours after food supply. Furthermore, A. tepida benefits from constant availability of fresh food rather than from a high amount of phytodetritus derived from a single food pulse. Our investigations showed that the foraminiferal impact on intertidal processing of phytodetrital carbon sources is species specific, temperature related and depends on developmental stage and input dynamics

  15. The trophic and metabolic pathways of foraminifera in the Arabian Sea: evidence from cellular stable isotopes

    Science.gov (United States)

    Jeffreys, R. M.; Fisher, E. H.; Gooday, A. J.; Larkin, K. E.; Billett, D. S. M.; Wolff, G. A.

    2015-03-01

    The Arabian Sea is a region of elevated productivity with the highest globally recorded fluxes of particulate organic matter (POM) to the deep ocean, providing an abundant food source for fauna at the seafloor. However, benthic communities are also strongly influenced by an intense oxygen minimum zone (OMZ), which impinges on the continental slope from 100 to 1000 m water depth. We compared the trophic ecology of foraminifera on the Oman and Pakistan margins of the Arabian Sea (140-3185 m water depth). These two margins are contrasting both in terms of the abundance of sedimentary organic matter and the intensity of the OMZ. Organic carbon concentrations of surficial sediments were higher on the Oman margin (3.32 ± 1.4%) compared to the Pakistan margin (2.45 ± 1.1%) and sedimentary organic matter (SOM) quality estimated from the Hydrogen Index was also higher on the Oman margin (300-400 mg HC mg TOC-1) compared to the Pakistan margin (respiration; this was most notable on the Pakistan margin. Depleted foraminiferal δ15N values, particularly at the Oman margin, may reflect feeding on chemosynthetic bacteria. We suggest that differences in productivity regimes may be responsible for the differences observed in foraminiferal isotopic composition. In addition, at the time of sampling, whole jellyfish carcasses (Crambionella orsini) and a carpet of jelly detritus were observed across the Oman margin transect. Associated chemosynthetic bacteria may have provided an organic-rich food source for foraminifera at these sites. Our data suggest that foraminifera in OMZ settings can utilise a variety of food sources and metabolic pathways to meet their energetic demands.

  16. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

    Directory of Open Access Journals (Sweden)

    Joost W van Dam

    Full Text Available Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m, while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v/F(m, interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v/F(m and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1. The mixture toxicity model of Independent Action (IA described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.

  17. A survey of benthic assemblages of foraminifera in tropical coastal waters of pulau pinang, malaysia.

    Science.gov (United States)

    Minhat, Fatin Izzati; Yahya, Khairun; Talib, Anita; Ahmad, Omar

    2013-08-01

    The distribution of benthic Foraminifera throughout the coastal waters of Taman Negara Pulau Pinang (Penang National Park), Malaysia was studied to assess the impact of various anthropogenic activities, such as fishing, ecotourism and floating cage culture. Samples were obtained at 200 m intervals within the subtidal zone, extending up to 1200 m offshore at Teluk Bahang, Teluk Aling, Teluk Ketapang and Pantai Acheh. The depth within coastal waters ranged between 1.5 m and 10.0 m, with predominantly muddy substrate at most stations. Water quality analysis showed little variation in micronutrient (nitrite, NO2; nitrate, NO3; ammonia, NH4 and orthophosphate, PO4) concentrations between sampling stations. Temperature (29.6±0.48°C), salinity (29.4±0.28 ppt), dissolved oxygen content (5.4±0.95 mg/l) and pH (8.5± 0.13) also showed little fluctuation between stations. A total of nine genera of foraminifera were identified in the study (i.e., Ammonia, Elphidium, Ammobaculites, Bigenerina, Quinqueloculina, Reopax, Globigerina, Textularia and Nonion). The distribution of benthic foraminifera was dominated by opportunistic groups that have a high tolerance to anthropogenic stressors. Ammonia had the highest frequency of occurrence (84.7%), followed by Bigenerina (50%), Ammobaculites (44.2%) and Elphidium (38.9%). The Ammonia-Elphidium Index (AEI) was used to describe the hypoxic condition of benthic communities at all sites. Teluk Bahang had the highest AEI value. The foraminiferal assemblages and distribution in Teluk Bahang, Teluk Aling, Teluk Ketapang and Pantai Acheh showed no correlation with physical or chemical environmental parameters.

  18. How to react to shallow water hydrodynamics: The larger benthic foraminifera solution.

    Science.gov (United States)

    Briguglio, Antonino; Hohenegger, Johann

    2011-11-01

    Symbiont-bearing larger benthic foraminifera inhabit the photic zone to provide their endosymbiotic algae with light. Because of the hydrodynamic conditions of shallow water environments, tests of larger foraminifera can be entrained and transported by water motion. To resist water motion, these foraminifera have to build a test able to avoid transport or have to develop special mechanisms to attach themselves to substrate or to hide their test below sediment grains. For those species which resist transport by the construction of hydrodynamic convenient shapes, the calculation of hydrodynamic parameters of their test defines the energetic input they can resist and therefore the scenario where they can live in. Measuring the density, size and shape of every test, combined with experimental data, helps to define the best mathematical approach for the settling velocity and Reynolds number of every shell. The comparison between water motion at the sediment-water interface and the specimen-specific settling velocity helps to calculate the water depths at which, for a certain test type, transport, deposition and accumulation may occur. The results obtained for the investigated taxa show that the mathematical approach gives reliable results and can discriminate the hydrodynamic behaviour of different shapes. Furthermore, the study of the settling velocities, calculated for all the investigated taxa, shows that several species are capable to resist water motion and therefore they appear to be functionally adapted to the hydrodynamic condition of its specific environment. The same study is not recommended on species which resist water motion by adopting hiding or anchoring strategies to avoid the effect of water motion.

  19. Distribution and Geochemical Composition of Living Planktonic Foraminifera in the Caribbean Sea

    Science.gov (United States)

    Jentzen, A.; Schönfeld, J.; Nuernberg, D.

    2014-12-01

    Planktonic foraminifera are widely used for paleoceanographic reconstructions of different water mass dynamics. For accurate reconstruction, it is crucial to understand the habitat, ecology and shell chemistry of single species. In this study, living planktonic foraminifera were collected with a multi closing net in the Caribbean Sea during R/V Meteor cruises M78/1 in 2009, and M94, M95 in 2013 respectively. The population structure in surface to subsurface waters was assessed and related to salinity, temperature and chlorophyll concentrations. Stable isotopes and trace elements of shell calcite are measured to improve the proxy calibration. At all stations, the highest standing stock was observed in the near-surface layer and the highest population densities in the eastern Caribbean Sea. Markedly low abundances of foraminifera were recognized in Gulf of Paria and close to the Orinoco River plume. The most frequent species in the Caribbean were Globigerinoides sacculifer, Globigerinita glutinata, Globigerinoides ruber, Globigerinella calida, and Neogloboquadrina dutertrei. Abundance maxima of G. sacculifer and G. ruber were always recorded in the surface water. The preferred habitat of N. dutertrei was the near-surface mixed layer, even though the species has been commonly referred to calcify in the thermocline. As expected, the deep dweller Globorotalia truncatulinoides (dextral) was mainly observed in upper intermediate waters, although juvenile specimens were found at shallower depths. Plankton tow data showed that shallow-living species adjusted their habitat to surface water masses, which deepened in the southern Caribbean Sea from East to West. Furthermore, intermediate to deep dwellers appear to prevail in surface or subsurface waters during the early stage of their life cycle.

  20. Stable carbon and oxygen isotope study on benthic foraminifera: Implication for microhabitat preferences and interspecies correlation

    Indian Academy of Sciences (India)

    Ajoy K Bhaumik; Shiv Kumar; Shilpi Ray; G K Vishwakarma; Anil K Gupta; Pushpendra Kumar; Kalachand Sain

    2017-07-01

    Stable isotopes of benthic foraminifera have widely been applied in micropalaeontological research to understand vital effects in foraminifera. Isotopic fractionations are mainly controlled by ontogeny, bottom/pore water chemistry, habitat preference, kinetic effect and respiration. Discontinuous abundance of a species for isotopic analysis has forced us to select multiple species from down-core samples. Thus standardisation factors are required to convert isotopic values of one species with respect to other species. The present study is pursued on isotopic values of different pairs of benthic foraminifera from the Krishna–Godavari basin and Peru offshore to understand habitat-wise isotopic variation and estimation of isotopic correction factors for the paired species (Cibicides wuellerstorfi–Bulimina marginata, Ammonia spp.–Loxostomum amygdalaeformis and Bolivina seminuda–Nonionella auris). Infaunal species (B. marginata, Ammonia spp. and N. auris) show a lighter carbon isotopic excursion with respect to the epifaunal to shallow infaunal forms (C. wuellerstorfi, L. amygdalaeformis and B. seminuda). These lighter δ13C values are related to utilisation of CO2 produced by anaerobic remineralisation of organic matter. However, enrichment of δ18O for the deeper microhabitat (bearing lower pH and decreased CO32−) is only recorded in case of B. marginata. It is reverse in case of N. auris and related to utilisation of respiratory CO2 and internal dissolve inorganic carbon pool. Estimation of interspecies isotopic correction factors for the species pairs (δ13C of C. wuellerstorfi–B. marginata, L. amygdalaeformis–Ammonia spp., N. auris–B. seminuda) and δ18O of C. wuellerstorfi–B. marginata are statistically reliable and may be used in palaeoecological studies.

  1. Distribution of upwelling index planktonic foraminifera in the sediments of the western continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    .). This further confirms that the dissolution of radiolar ians occurs on the upper as well as on the lower slope. However, the chemical and sedimentological factors determining the -rate of dissolution of siliceous micro fossils are not well understood... with the high productivity caused by 'i REFFRF"foraminifera and biogeographic pallern of life and fossil assemblages in the Indian Ocean. MicropaleontoloKY, 23. 4, 369-414. Berger W. II., L...

  2. Distribution of benthic foraminifera within oxygen minima zone, off central west coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumder, A.; Henriques, P.J.; Nigam, R.

    flux and bottom water oxygenation? A case history from the northern Arabian Sea. Paleogeogr. Paleoclimat. Paleoecol, v. 161, pp. 337- 359. Gooday, A. J., Bernhard, J .M., Levin, L. S. and Suhr, S. B. (2000). Foraminifera in the Arabian Sea oxygen... minimum zone and other oxygen-deficient settings: taxonomic composition, diversity, and relation to metazoan faunas. Deep-Sea Res. Part II, v. 47, pp. 25-54. Groves, D. G. and Hunt, L. M. (1980). Ocean World Encyclopedia. McGraw Hill Book Company, New...

  3. The role of benthic foraminifera in the benthic nitrogen cycle of the Peruvian oxygen minimum zone

    Directory of Open Access Journals (Sweden)

    N. Glock

    2012-12-01

    Full Text Available The discovery that foraminifera are able to use nitrate instead of oxygen as energy source for their metabolism has challenged our understanding of nitrogen cycling in the ocean. It was evident before that only prokaryotes and fungi are able to denitrify. Rate estimates of foraminiferal denitrification were very sparse on a regional scale. Here, we present estimates of benthic foraminiferal denitrification rates from six stations at intermediate water depths in and below the Peruvian oxygen minimum zone (OMZ. Foraminiferal denitrification rates were calculated from abundance and assemblage composition of the total living fauna in both, surface and subsurface sediments, as well as from individual species specific denitrification rates. A comparison with total benthic denitrification rates as inferred by biogeochemical models revealed that benthic foraminifera account for the total denitrification on the shelf between 80 and 250 m water depth. They are still important denitrifiers in the centre of the OMZ around 320 m (29–56% of the benthic denitrification but play only a minor role at the lower OMZ boundary and below the OMZ between 465 and 700 m (3–7% of total benthic denitrification. Furthermore, foraminiferal denitrification was compared to the total benthic nitrate loss measured during benthic chamber experiments. Foraminiferal denitrification contributes 1 to 50% to the total nitrate loss across a depth transect from 80 to 700 m, respectively. Flux rate estimates ranged from 0.01 to 1.3 mmol m−2 d−1. Furthermore we show that the amount of nitrate stored in living benthic foraminifera (3 to 705 µmol L−1 can be higher by three orders of magnitude as compared to the ambient pore waters in near surface sediments sustaining an important nitrate reservoir in Peruvian OMZ sediments. The substantial contribution of foraminiferal nitrate respiration to total benthic nitrate loss at the Peruvian margin

  4. Spatial distribution of living (Rose Bengal stained) benthic foraminifera in the Loire estuary (western France)

    Science.gov (United States)

    Mojtahid, M.; Geslin, E.; Coynel, A.; Gorse, L.; Vella, C.; Davranche, A.; Zozzolo, L.; Blanchet, L.; Bénéteau, E.; Maillet, G.

    2016-12-01

    Ninety-seven surface sediment samples were collected in September 2012 from intertidal and subtidal areas along the Loire estuary (western France). The main objective of this work is to study the spatial distributional patterns of living benthic foraminifera and their link to the environmental parameters (distance to sea, elevation, grain size, total organic carbon, trace metals, sedimentary carbonates, and polycyclic aromatic hydrocarbons) in the Loire estuary. Foraminiferal analysis was also extended to the dead assemblages in thirty-three surface samples from the lower inner estuary. The highest absolute densities of living benthic foraminifera are found in the lower inner estuary within the polyhaline domain. This is attributed to the presence of mudflats with abundant food source, i.e. microphytobenthos. The low densities found in the outer estuary (euhaline domain) are attributed partly to the sandy nature of the sediments and the food source inhabiting this substrate. The near absence of foraminifera in the inner estuary (mesohaline and polyhaline domains) is inferred to the physical disturbance resulting from the regular dredging of the navigation channel. The living assemblages are dominated by three typical estuarine species: Ammonia tepida and Haynesina germanica in the intertidal mudflats of the lower inner estuary and Cribroelphidium excavatum in the sandy subtidal sediments of the lower inner and outer estuary. In the Loire estuary, H. germanica has an unusual intermediate geographical distribution along the estuary between A. tepida and C. excavatum while in most temperate estuaries this species is present upstream in the mesohaline domain. This is most likely the result of the regular dredging of the navigation channel damaging its natural habitat. This might be also the explanation for the total absence of agglutinated species usually dominating the oligohaline domain. The canonical correspondence analysis shows that elevation (and its link to time

  5. Distribution and ecology of deep-water benthic foraminifera in the Gulf of Mexico

    Science.gov (United States)

    Poag, C.W.

    1984-01-01

    Bathyal and abyssal foraminifera in the Gulf of Mexico are distributed among thirteen generic predominance facies. Five predominance facies nearly encircle the Gulf basin along the slope and rise; a sixth predominance facies blankets the Sigsbee Plain, and a seventh is restricted to the Mississippi Fan. The remaining eight predominance facies have more restricted distributions. The areal patterns of these predominance facies can be related chiefly to water mass and substrate characteristics; modifications are brought about by calcite dissolution, upwelling, and sill depth. Analysis of ancient generic predominance facies is useful in predicting relative paleobathymetry and other paleoenvironmental properties. ?? 1984.

  6. Diversity, distribution, and morphological deformities among living Foraminifera in hypersaline Salwa Bay, Saudi Arabia

    Science.gov (United States)

    Olalekan Amao, Abduljamiu; Kaminski, Michael

    2016-04-01

    The Arabian Gulf is considered a naturally stressed environment due to extremes of salinity and summer temperatures. Anthropogenic influences such as rapid urbanisation projects, maritime transport, and large numbers of desalination plants and oil-related activities compounds the problem. Foraminifera are known to be resilient under such stressful conditions. The purpose of our study is to document the foraminiferal diversity and abundance in the hypersaline Salwa Bay area, near the Saudi Arabian-Qatar Border. We expect the foraminiferal fauna in Salwa Bay to be adapted to extremes in salinity, and we wish to document any species that might be endemic or uniquely adapted to the area. Shannon-Wiener index, relative abundance, species richness, and the percentage of morphological deformities were determined for samples collected from the bay. Salwa Bay is the most saline extension of the Arabian Gulf with high salinity, water temperature and evaporation rate, which is attributed to slow flushing rates, coral reef barriers and higher residency time of the water. Environmental parameters measured at the time of collection were depth (10-110 cm), salinity (52.6-53.0) total dissolved solids (48.8-49.4 g/l), and temperature (27-27.6°C). The foraminiferal assemblages in Salwa Bay are dominated by porcelaneous foraminifera, which include Peneroplis pertusus, Peneroplis planatus, Coscinospira hemprichii and Coscinospira acicularis. The most common species across the sampled transect is Peneroplis pertusus. Hyaline species were also found, but agglutinated foraminifera are absent. Diversity in Salwa Bay is lower compared with localities that have "normal" salinity, and many of the foraminifera display conspicuous morphological deformities. Approximately 55% of the assemblage exhibits mild to severe deformities such as fusion of two adults or double tests, protuberance on the spiral side, abnormal arrangement of the chambers, abnormal shape of the proloculus and modification

  7. Methane seep events of the southern Joetsu Knoll since middle Pleistocene based on benthic foraminifera

    Science.gov (United States)

    Oi, T.; Akiba, F.; Matsumoto, R.; Kakuwa, Y.

    2016-12-01

    Gas hydrates were collected at several sites off Joetsu which presented anomalous seismic structures. "Gas chimneys", major host structures for shallow gas hydrates, were recognized ROV off Joetsu in eastern margin of the Japan Sea, as were a number of active methane seeps. The assemblage components and carbon isotope of benthic foraminifera, which are ubiquitous in global marine settings, can indicate methane seep environments (Akimoto et al., 1994; Bhaumik and Gupta, 2007). Preliminary work by Oi et al. (2015) documented the obvious occurrences of methane related foraminifera, Rutherfordoides sp., in three core sediments recovered from Umitaka Spur, west Oki Trough and north Mogami Trough in the eastern margin of the Japan Sea, and found them to comprise the early part of the MIS 2, calculated to 28-25ka. These records suggest that active methane seep events might occur at the same time during early MIS 2, but were confined within the last 100ka. In this study, we analyzed benthic foraminiferal fossils from drilling core J04RB (core length 122 m; one of the gas hydrate bearing sites at a southern part of the Joetsu Knoll) in order to document methane seep events during the last 500ka. Firstly, we estimated sedimentation ages from diatom biostratigraphy and identification of Aso-1 tephra. Based on diatom components, we recognized a boundary between NPD (Neogene North Pacific diatom Zonations) 12 and NPD11, estimated at 300 ka (MIS8/9; Yanagisawa and Akiba, 1998). The bottom age was estimated to almost 530-560 ka (around MIS14) especially from the alternation with warm and cold diatom zones (Akiba et al., 2014). Secondary, we could suppose the paleoenvironments from benthic foraminifera as below. 1. The rare benthic foraminifera during the cold stages (MIS8, MIS10, and MIS12) indicate anoxic bottom conditions characteristic of falling sea level, just as with MIS 2. 2. We recognized the continuous distributions of tiny methane related specimens of Rutherfordoides sp

  8. Pliocene and Pleistocene chronostratigraphy and paleoenvironment of the Central Arctic Ocean, using deep water agglutinated foraminifera

    OpenAIRE

    Evans, J. R.; Kaminski, M.A

    1998-01-01

    Deep-water agglutinated foraminifera (DWAF) were studied from Cores PS2177-5, PS2200-5, PS2212-3 and PS2185-6; from the R/V POLARSTERN ARK-VIII/3 Cruise in the central Arctic Ocean. The sediments were non-calcareous containing a sparse assemblage of eleven DWAF species. A chronostratigraphic framework is presented for Cores PS2200-5 and PS2185-6. Paleoenvironmental data suggests a bathyal environment (2000-4000m) affected by water masses in the Arctic Ocean. The taxonomy of all of the DWAF fo...

  9. Pliocene foraminifera of Piedmont (north-western Italy: a synthesis of recent studies

    Directory of Open Access Journals (Sweden)

    Donata Violanti

    2005-10-01

    Full Text Available A synthesis of recent biostratigraphical and palaeoenvironmental studies on foraminifera assemblages of he Piedmont Pliocene (north-astern Monferrato, Astigiano, Langhe and Monregalese is discussed. In the region, biozone MPl1 is documented by typical Sphaeroidinellopsis assemblages only in its central area. Rich and diversified assemblages of MPl2 biozone, with Globorotalia margaritae Bolli & Bermudez, and MPl3 biozone, with G. margaritae and G. puncticulata (Deshayes, are indicative of the upper epibathyal zone, and suggest palaeoenvironmental conditions similar to those of coeval pelagic successions of Sicily and the Tyrrhenian Sea. Already along biozone MPl3, and chiefly biozone MPl4, with G. puncticulata, less diversified assemblages become more widespread, indicating shelf palaeoenvironments, subject to heavy transport of displaced foraminifera from more inner neritic zones. In the study area most inner neritic and shallow outer neritic microfaunas are devoid of biostratigraphic markers; only few silty sediments yield Bulimina basispinosa Tedeschi & Zanmatti and Globobulimina ovula (d’Orbigny, reported from the Middle Pliocene, and can be correlated to the MPl5 biozone.

  10. First and last occurrences of Quaternary benthic foraminifera in the Gulf of Mexico: Relation to paleoceanography

    Energy Technology Data Exchange (ETDEWEB)

    Denne, R.A.; Sen Gupta, B.K. (Louisiana State Univ., Baton Rouge (USA))

    1990-09-01

    The distribution record of benthic foraminifera in late Pleistocene and Recent sediments of the northwestern Gulf of Mexico indicates that stratigraphic occurrences of species are affected by paleoceanography Two species that are very common in the modern gulf, Bulimina alazanensis and Osangularia culter, were not present in the area during the last glacial, owing to the absence of Subantarctic Intermediate Water. They reappeared at about 12,500 YBP, with the reintroduction of this water mass into the gulf At the same time, Valvulineria sp. A, common during the last glacial, disappeared. This was caused by the cessation of production of the North Atlantic Intermediate Water during the deglaciation. These events, probably isochronous throughout the gulf, do not represent the true first and last occurrences of the species, but may prove useful for the recognition of significant stratigraphic datums. Overall water-depth changes or bathymetric shifts of water-mass boundaries may lead to the disappearance of certain species in one area, but not in others. This results in a diachronous stratigraphic datum, or stratigraphic climbing. Even planktonic foraminifera can be affected by such processes, because of narrowly stenothermal and stenohaline adaptations of many species, in the context of shoreline shifts and climatic changes.

  11. Paleoenvironmental changes during the late Quaternary as inferred from foraminifera assemblages in the Laizhou Bay

    Institute of Scientific and Technical Information of China (English)

    YAO Jing; YU Hongjun; XU Xingyong; YI Liang; CHEN Guangquan; SU Qiao

    2014-01-01

    Controlled by climate changes, there were three large-scale transgressions and regressions around the Bohai Sea during the late Quaternary, which were accepted by most geologists. However, a big controversy still exists about the time when the transgressions occurred separately. In order to find out the process of the paleoenvironmental changes around the Bohai Sea in the late Quaternary, the foraminifera assemblages from a new borehole Lz908 in the southern coast of the Laizhou Bay were studied, and then the transgressive strata were indentified. Combined with accelerator mass spectrometry radiocarbon 14C (AMS14C) and opti-cally stimulated luminescence (OSL) ages, the occurrence time of these transgressions were re-determined. The result showed that three major large-scale transgressions occurred separately at the beginning of ma-rine isotopic stage 7 (MIS7), the last interglacial period (MIS5) and the Holocene. In addition, a small-scale transgression occurred in the mid-MIS6, and the corresponding transgressive stratum was deposited. The transgressive deposition of MIS3 was also discovered in this study. However, the characteristics of the fora-minifera indicated the environment during this period was colder than that in the MIS5. By comparison with the global sea-level changes, the paleoenvironmental changes around the Bohai Sea in the late Quaternary can be consistent with the global climate changes.

  12. Lunar periodicity in the shell flux of some planktonic foraminifera in the Gulf of Mexico

    Science.gov (United States)

    Jonkers, L.; Reynolds, C. E.; Richey, J.; Hall, I. R.

    2014-12-01

    Synchronised reproduction offers clear benefits to planktonic foraminifera - an important group of marine calcifiers - as it increases the chances of successful gamete fusion. Such synchrony requires tuning to an internal or external clock. Evidence exists for lunar reproductive cycles in some species, but its recognition in shell flux time series has proven difficult, raising questions about reproductive strategies. Using spectral analysis of a 6 year time series (mostly at weekly resolution) from the northern Gulf of Mexico we show that the shell flux of Globorotalia menardii, Globigerinella siphonifera, Orbulina universa, Globigerinoides sacculifer and in Globigerinoides ruber (both pink and white varieties) is characterised by lunar periodicity. The fluxes of Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerinella calida, Globorotalia crassaformis and Globigerinita glutinata do not show significant spectral power at the lunar frequency. If present, lunar periodicity is superimposed on longer term/seasonal changes in the shell fluxes, but accounts for a significant part of the variance in the fluxes. The amplitude of the lunar cycle increases roughly proportional with the magnitude of the flux, demonstrating that most of the population is indeed affected by lunar-phased synchronisation. Phasing of peak fluxes appears species-specific, with G. menardii, O. universa and G. sacculifer showing most peaks around the full moon and G. ruber one week later. Contrastingly, peaks G. siphonifera occur dominantly around new moon. Very limited literature exists on lunar phasing of foraminiferal export fluxes, but spatial differences in its presence may exist, corroborating the exogenous nature of lunar synchrony in planktonic foraminifera.

  13. Investigating Carbonate System Perturbations across the Cretaceous-Palaeogene Transition using Boron Isotopes in Planktonic Foraminifera.

    Science.gov (United States)

    Henehan, M. J.; Hull, P. M.; Planavsky, N. J.; Huber, B. T.; Thomas, E.

    2014-12-01

    The interval spanning the latest Maastrichtian to the early Palaeocene has great potential in helping to elucidate the stabilising mechanisms on the Earth's carbonate system on both long and very short geological timescales, from the geologically-instantaneous production of sulphate-rich aerosols and nitrogen oxides from the K-Pg bolide impact to the relatively more gradual degassing from Deccan volcanism in the latest Maastrichtian. The extent to which ocean pH (and atmospheric CO2 concentrations) changed in response to these contrasting acidification pressures, and the timescales of their recovery, may provide unique insight into the efficiency of the Earth's oceans in buffering greenhouse gas increases (through carbonate dissolution, weathering-derived alkalinity flux, and biological carbon cycling). The boron isotope palaeo-pH proxy in planktic foraminifera is well suited to such investigations, but its application over this interval has been problematic, not least due to a scarcity of sample material and a near-complete turnover of planktonic foraminiferal species across the K-Pg boundary. To attempt to circumvent these issues, we investigate the biological influences on boron isotope signals in Maastrichtian and Danian planktonic foraminifera, with the goal of producing more accurate palaeo-pH reconstructions. With these findings in mind, we present preliminary constraints on ocean pH and carbonate system dynamics across this critical interval of geological time.

  14. Benthic foraminifera from two coastal lakes of southern Latium (Italy). Preliminary evaluation of environmental quality.

    Science.gov (United States)

    Carboni, Maria Gabriella; Succi, Maria Cristina; Bergamin, Luisa; Di Bella, Letizia; Frezza, Virgilio; Landini, Bruna

    2009-01-01

    Benthic foraminifera and sediment texture were studied on a total of 37 samples, collected from two brackish-water coastal basins: Fogliano Lake and Lungo Lake (central Italy). The research was performed as a preliminary low-cost survey to highlight the degree of the environmental stress and to recognize a possible anthropogenic disturbance. The sedimentological and foraminiferal data were processed by bivariate and multivariate statistical analysis. Three distinct assemblages, referable to different environments were recognized for the Fogliano Lake: inner, intermediate and outer lagoon. Only the outer lagoon assemblage was found in the Lungo Lake. The distribution of foraminifera in the Fogliano Lake suggests a natural environmental stress probably due to the ecological instability typical of marginal environments, while the absence of the inner and intermediate lagoon assemblages in the Lungo Lake suggests an environmental disturbance possibly related to human activities. An interdisciplinary survey including geochemical analyses is recommended in order to deduce the nature and degree of pollution in the Lungo Lake.

  15. Tiny Fossils, Big Impact: Sedimentology of a Foraminifera-Enriched Detachment Horizon of a Large Retrogressive Submarine Landslide in the Gulf of Mexico

    Science.gov (United States)

    Hodelka, B. N.; Sawyer, D.

    2014-12-01

    A 2-meter thick condensed section enriched in foraminifera is the final detachment horizon of a retrogressive submarine landslide, in the Ursa Basin, northern Gulf of Mexico. The high concentration of foraminifera (up to 900% relative to background values) in this layer produces a high porosity (up to 5 porosity units), low sonic velocity, low resistivity, and high gamma ray zone relative to the background clay properties. A high acoustic impedance contrast occurs at this interface and results in a high-amplitude reflection that is widespread and easily mappable in seismic. Integrated Ocean Drilling Program Expedition 308 Site U1324 cored and logged this layer. We acquired 31 samples: 22 from the foraminifera-enriched layer and 9 to establish background values. Objectives were to (1) quantify foraminifera enrichment relative to background values, (2) describe the spatial arrangement of foraminifera within the clay, (3) identify the foraminifera assemblage, and (4) determine particle size. CT images show individual foraminifera dispersed within the clay and are predominantly in-tact. Foraminifera concentration is variable within the layer but average 0.75 grams of foraminifera per gram of sediment (maximum = 0.97 grams of foraminifera per gram of sediment). Foraminifera concentration correlates to particle size of the hosting sediment: highest foraminifera concentrations occur within the finest-grained samples and vice versa. This explains the high gamma ray response. The assemblage is expected for this time interval in the Late Pleistocene (~24 kya) with an abundance of Globorotalia ruber and Globorotalia sacculifer. This suggests the layer is in-situ and a result of a pause in terrigenous sedimentation. The landslide was a multi-detachment event that initiated in a deeper horizon but retrogressively cut upwards. The condensed section was a preferred detachment horizon but only minimal sliding occurred before further movement ceased. One potential mechanism to

  16. The FORCLIM Eco-Physiological Growth Model for Planktic Foraminifera: a new Tool to Reconstruct Ecological Niches, Abundance and Potential Depth and Season of Growth for Fossil Foraminifera Species in Ocean Sediment Records

    Science.gov (United States)

    Lombard, F.; Labeyrie, L.; Michel, E.; Lea, D.; Spero, H. J.; Forclim, M. O.

    2007-12-01

    Paleocean hydrological reconstructions derived from planktic foraminifera isotopic ratios (δ18O and δ13C) or trace element ratio (Mg/Ca) are poorly constrained, for lack of precise knowledge on seasonality and water depth of test formation. This is particularly limiting for reconstruction of the thermocline characteristics. Various calibrations have been published, based on statistical correlation with core tops fossil fauna, sediment traps or plankton net collection. We present here what we think is the first eco-physiological model reproducing the growth of different foraminifera species in function of environmental parameter. By reproducing the main physiological rates of foraminifera (nutrition, respiration, symbiotic photosynthesis), this model estimates their growth in function of temperature, light availability and food concentration. The model is now calibrated for the species Neogloboquadrina pachyderma (dextral and sinistral forms), Neogloboquadrina dutertrei, Globigerina bulloides, Globigerinoides ruber, Globigerinoides sacculifer, Globigerinella siphonifera and Orbulina universa. Most of the model parameters are derived from newly performed experimental observations or from published data and only the influence of food concentration (in a Chl a basis) was calibrated with field observations. Using satellite data, the model predict the seasonal distribution of dominant foraminifer species over 576 field observations worldwide with efficiency higher than 60%. Moreover, the growth rate estimated for each foraminifera species can be used as an abundance indicator which allows prediction of the season and water depth at which most of the population has developed. This offers larges perspectives for both actual understanding of foraminifera role in the carbon/carbonate ocean cycle and for better quantification of paleoceanographic proxies. Forclim is a program supported by the Agence Nationale pour la Recherche and Institut National des Sciences de l

  17. Seaweed fails to prevent ocean acidification impact on foraminifera along a shallow-water CO2 gradient.

    Science.gov (United States)

    Pettit, Laura R; Smart, Christopher W; Hart, Malcolm B; Milazzo, Marco; Hall-Spencer, Jason M

    2015-05-01

    Ocean acidification causes biodiversity loss, alters ecosystems, and may impact food security, as shells of small organisms dissolve easily in corrosive waters. There is a suggestion that photosynthetic organisms could mitigate ocean acidification on a local scale, through seagrass protection or seaweed cultivation, as net ecosystem organic production raises the saturation state of calcium carbonate making seawater less corrosive. Here, we used a natural gradient in calcium carbonate saturation, caused by shallow-water CO2 seeps in the Mediterranean Sea, to assess whether seaweed that is resistant to acidification (Padina pavonica) could prevent adverse effects of acidification on epiphytic foraminifera. We found a reduction in the number of species of foraminifera as calcium carbonate saturation state fell and that the assemblage shifted from one dominated by calcareous species at reference sites (pH ∼8.19) to one dominated by agglutinated foraminifera at elevated levels of CO2 (pH ∼7.71). It is expected that ocean acidification will result in changes in foraminiferal assemblage composition and agglutinated forms may become more prevalent. Although Padina did not prevent adverse effects of ocean acidification, high biomass stands of seagrass or seaweed farms might be more successful in protecting epiphytic foraminifera.

  18. Relict benthic foraminifera in surface sediments off central east coast of India as indicator of sea level changes

    Digital Repository Service at National Institute of Oceanography (India)

    Rana, S.S.; Nigam, R.; Panchang, R.

    , Radiocarbon dates and Holocene sea-level change along the Cuddalore and Odinur coast, Tamil Nadu, Curr. Sci., 91(2006) 362-367. 14 Langer M R & Hottinger L, Biogeography of selected “larger” foraminifera, Micropaleontology, 46(2000), supplement no.1, 105...

  19. Chekhovichia, a new generic replacement name for Rotalites Leleshus 1970 (Anthozoa: Heliolitoidea) non Lamarck 1801 (Protista: Foraminifera).

    Science.gov (United States)

    Doweld, Alexander B

    2015-10-29

    The genus Rotalites was established by Leleshus (1970: 97) for fossil Upper Silurian heliolitoids (Anthozoa) from Southern Tien Shan. However, the name is preoccupied by Rotalites Lamarck (1801: 401) of Foraminifera (Protista) (cf. Loeblich & Tappan, 1987). In accordance with the International Code of Zoological Nomenclature, Chekhovichia nom. nov. is proposed here as a replacement name for Rotalites Leleshus non Lamarck.

  20. Late cretaceous foraminifera, paleoenvironments, and paleoceanography of the rosario formation, San Antonio del Mar, Baja California, Mexico

    Science.gov (United States)

    Maestas, Y.; MacLeod, K.G.; Douglas, R.; Self-Trail, J.; Ward, P.D.

    2003-01-01

    The 315 m of Rosario Formation exposed at the San Antonio del Mar (SADM) section (Baja California, Mexico) contains moderately-to-well preserved benthic and planktic foraminifera, calcareous nannofossils, and molluscs. Nannofossils suggest most of the SADM section was deposited within a narrow interval of the late Campanian (CC21-CC22), whereas foraminifera and molluscs suggest a younger maximum age (younger than the Globotruncana ventricosa Zone) and allow deposition over a longer interval of time. Planktic foraminifera at SADM represent common Tethyan taxa. They are largely restricted to the lower and middle portions of the section and comprise 0-???40% of foraminiferal assemblages. Stable isotopic analyses of Rugoglobigerina rugosa yield ??18OV-PDB values from -2.27%, to -2.82%, corresponding to salinity-corrected paleotemperature estimates of 26-30??C for the Late Cretaceous eastern Pacific. These estimates are as warm as modern tropical temperatures and are similar to tropical paleotemperature estimates from ??18O analyses of exceptionally preserved Maastrichtian samples; however, they are considerably warmer than most tropical Campanian-Maastrichtian estimates. Benthic foraminifera indicate outer shelf paleodepths with a slight increase in depth or decrease in benthic oxygen levels in the upper parts of the interval studied. The change in the benthic assemblage corresponds to an ???1??? positive shift in benthic ??O18, suggesting a relationship between benthic assemblages and an inferred increase in the local intensity of upwelling.

  1. Recent benthic foraminifera and sedimentary facies from mangrove swamps and channels of Abu Dhabi (United Arab Emirates)

    Science.gov (United States)

    Fiorini, Flavia; Odeh, Weaam A. S. Al; Lokier, Stephen W.; Paul, Andreas

    2016-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations in several coastline environments (mangrove swamps and channels) located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of living and dead benthic foraminifera in different sedimentary facies in the mangal and in the surrounding area comprising natural environments of the upper and lower intertidal area (mud flats and channels) and areas modified by anthropogenic activities (dredged channels). The fine-grain sediments collected near mangrove (Avicenna marina) roots presented a high abundance of living and dead foraminifera tests. The assemblages in these samples show very low diversity and are almost entirely constituted of small-sized opportunistic species belonging to the genera Ammonia and Elphidium. In particular: • Samples collected on the mud flat and in ponds at the margin of the channel show a foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Triloculina, Quinqueloculina, Peneroplis and Spirolina. • Samples collected in the lower (wet) intertidal area close to Avicenna marina roots, presented a low-diversity assemblage mostly comprising opportunistic foraminifera of the genera Ammonia and Elphidium along with rare miliolidae. • Samples from the upper intertidal area (dry) close to Avicenna marina roots, produced an assemblage exclusively composed of small-sized opportunistic Ammonia and Elphidium, together with abundant specimens belonging to the genera Trochammina. Throchammina specimens have not been previously recorded from Recent sedimentary samples of

  2. Effect of light on photosynthetic efficiency of sequestered chloroplasts in intertidal benthic foraminifera (Haynesina germanica and Ammonia tepida)

    Science.gov (United States)

    Jauffrais, Thierry; Jesus, Bruno; Metzger, Edouard; Mouget, Jean-Luc; Jorissen, Frans; Geslin, Emmanuelle

    2016-05-01

    Some benthic foraminifera have the ability to incorporate functional chloroplasts from diatoms (kleptoplasty). Our objective was to investigate chloroplast functionality of two benthic foraminifera (Haynesina germanica and Ammonia tepida) exposed to different irradiance levels (0, 25, 70 µmol photon m-2 s-1) using spectral reflectance, epifluorescence observations, oxygen evolution and pulse amplitude modulated (PAM) fluorometry (maximum photosystem II quantum efficiency (Fv/Fm) and rapid light curves (RLC)). Our results clearly showed that H. germanica was capable of using its kleptoplasts for more than 1 week while A. tepida showed very limited kleptoplastic ability with maximum photosystem II quantum efficiency (Fv/Fm = 0.4), much lower than H. germanica and decreasing to zero in only 1 day. Only H. germanica showed net oxygen production with a compensation point at 24 µmol photon m-2 s-1 and a production up to 1000 pmol O2 cell-1 day-1 at 300 µmol photon m-2 s-1. Haynesina germanica Fv/Fm slowly decreased from 0.65 to 0.55 in 7 days when kept in darkness; however, it quickly decreased to 0.2 under high light. Kleptoplast functional time was thus estimated between 11 and 21 days in darkness and between 7 and 8 days at high light. These results emphasize that studies about foraminifera kleptoplasty must take into account light history. Additionally, this study showed that the kleptoplasts are unlikely to be completely functional, thus requiring continuous chloroplast resupply from foraminifera food source. The advantages of keeping functional chloroplasts are discussed but more information is needed to better understand foraminifera feeding strategies.

  3. Species diversity variations in Neogene deep-sea benthic foraminifera at ODP Hole 730A, western Arabian Sea

    Indian Academy of Sciences (India)

    Yuvaraja Arumugm; Anil K Gupta; Mruganka K Panigrahi

    2014-10-01

    Deep-sea benthic foraminifera are an important and widely used marine proxy to understand paleoceanographic and paleoclimatic changes on regional and global scales, owing to their sensitivity to oceanic and climatic turnovers. Some species of benthic foraminifera are sensitive to changes in water mass properties whereas others are sensitive to organic fluxes and deep-sea oxygenation. Benthic faunal diversity has been found closely linked to food web, bottom water oxygen levels, and substrate and water mass stability. The present study is aimed at analyzing species diversity trends in benthic foraminifera and their linkages with Indian monsoon variability during the Neogene. Species diversity of benthic foraminifera is examined in terms of number of species (S), information function (H), equitability (E) and Sanders’ rarefied values, which were combined with relative abundances of high and low productivity benthic foraminifera at Ocean Drilling Program Hole 730A, Oman margin, western Arabian Sea. The Oman margin offers the best opportunity to understand monsoon-driven changes in benthic diversity since summer monsoon winds have greater impact on the study area. The species diversity was higher during the early Miocene Climatic Optimum (∼17.2–16.4 Ma) followed by a decrease during 16.4–13 Ma coinciding with a major increase in Antarctic ice volume and increased formation of Antarctic Bottom Water. All the diversity parameters show an increase during 13–11.6 Ma, a gradual decrease during 11.6–9 Ma and then an increase with a maximum at 7 Ma. Thereafter the values show little change until 1.2 Ma when all the parameters abruptly decrease. The benthic foraminiferal populations and diversity at Hole 730A were mainly driven by the Indian monsoon, and polar waters might have played a minor or no role since early Neogene period as the Arabian Sea is an enclosed basin.

  4. Microfacies analysis of foraminifera rich sedimentary rocks from the Desert Plateau, central Egypt.

    Science.gov (United States)

    Karnitschar, C.; Briguglio, A.; Hohenegger, J.

    2012-04-01

    Microfacies analysis on some samples from the Thebes Group have been carried on by means of thin sections. The study area is included in the Libyan Desert Plateau (central Egypt) at following coordinates N27° 36'30.58" E29° 44'58.34", near the biggest dune of Egypt, the Ghard Abu Muharik. Because of the round shape of the rocks and the desert patina on the surface they could easily be classified as the so called "Melonstones", which are located more southwards and mainly composed by stromatolites. On the contrary, the investigated samples show a completely different fauna and therefore have been separated from the "Melonstones". Even if shape and size are very similar and the desert patina covers all surfaces the same way the differences are impressive. To investigate the samples, two thin-sections have been prepared and analyzed at the microscope. The observed fauna is composed by: agglutinated benthic foraminifera (e.g., Dictyoconus egypticus), complex larger miliolids (e.g., Pseudolacazina cf. danatae, Fabularia sp.), alveolinids (Alveolina vredenburgi), green algae (Dasycladaceae), echinoids and corals. Because of the presence of symbionts bearing larger benthic foraminifera, which need light to feed photosymbionts, the rock was formed in a shallow water environment. With the abundant rock-building benthic foraminifera and calcareous algae the limestone shows a tendency to the packstone/wackestone facies. Based on the presence of Alveolina vredenburgi, the age of the samples can be estimate as lowermost Eocene belonging to the shallow benthic zone 5 (sensu Serra-Kiel et al., 1998). According the obtained data on stratigraphy and palaeoecology, a partial palaeoenvironmental reconstruction is possible for the Libyan Desert Plateau where outcrops are largely missing. Because of the round shape of the samples and the patina which covers them all around it can be assumed that they have been transported from longer distance. According to the geological map of the

  5. Determinants of Seasonality of Planktonic Foraminifera Shell Flux: Consequences for Paleoproxies

    Science.gov (United States)

    Jonkers, L.; Kucera, M.

    2014-12-01

    Planktonic foraminifera are widely used proxy carriers in paleoceanography. The flux of foraminiferal shells to the sea floor is not even throughout the year, creating a seasonal bias in the surface conditions recorded in an average fossil sample. This bias, and its changes through time, may account for an important part of the variability in paleoclimate records, but it is often ignored because of limited knowledge on the determinants of flux seasonality. To address this issue we have compiled a global dataset on shell flux seasonality from sediment traps. The database contains 38 globally distributed time series of at least one year and covers >20 species. We use periodic regression to objectively determine peak flux timing and amplitude. Significant seasonality is observed in 80 % of the cases studied and we distinguish three distinct groups of foraminifera with different modes of seasonality. This division is independent of ocean basin or upwelling and appears to reflect three principle patterns of phenology. Warm-water and symbiont-bearing species change flux seasonality by concentrating a larger proportion of the annual flux in a shorter period in colder water. Peak flux timing appears random at high temperatures and shifts towards autumn at lower temperatures. Seasonal flux variability is small at high temperatures (within their optimal range) resulting in a negligible seasonal bias. In colder waters the timing appear constant and the strength of the peak flux can be predicted by temperature. Temperate and cold-water dwellers adjust their peak timing with average temperature. Peak flux in these species occurs later during the year at lower temperatures and follows chlorophyll maxima by approximately a month. The strength of peak flux is similar across the temperature range, but the association with productivity allows for prediction of the timing of peak flux. Peak flux of deep-dwelling seems to occur in spring independent of temperature, which may agree

  6. Standard biostratigraphic scheme of planktonic foraminifera for the Nankai Trough Seismogenic Zone, northwestern Pacific

    Science.gov (United States)

    Hayashi, H.; Nishi, H.; Ikehara, M.; Tanaka, T.; Matsuzaki, K.

    2013-12-01

    The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) was planned for comprehensive understanding of repeated mega-earthquakes along the subduction boundary of the Philippine Sea Plate. One of fundamental purposes of this project is to reconstruct the tectonic history of the seismogenic zone. For this purpose, we need an integrated stratigraphic approach including biostratigraphic method. With respect to previous studies, sediments from the Kumano forarc basin and accretionary complex of the seismogenic zone contain calcareous microfossils such as planktonic foraminifera (Hayashi et al., 2011). In addition, Miocene to Pliocene ocean-floor sediments in the Shikoku basin also contain planktonic foraminifera with several barren interval (Expedition 322 Scientists, 2010). We present a composite planktonic foraminiferal biostratigraphy using five drilling sites of the NanTroSEIZE transect. These sites are placed in the Kumamo forarc basin (Site C0002), upper trench-slope basin (Site C0001), trench slope (Sites C0022), lower trench-slope basin(C0021) and the Shikoku basin (Site C0012). Total 43 biohorizons were recognized from middle Miocene to Pleistocene sequences with three grades of reliability. Among them, 36 biohorizons were reported with astronomically-tuned ages by Wade et al. (2011) and Tian et al. (2008). These astronomical-tuned ages of biohorizons are in good agreement with each other and consistent with magnetostratigraphy. In particular notice to the comparison between the two different timetables, Tian et al.'s (2008) biohorizons are more concordant with calcareous nannofossil data than those of Wade et al. (2011). It can be explained by the difference of biogeographic provinces of planktonic foraminifera: Tian et al. (2008) constructed their astronomically-tuned records by using sediments from ODP Site 1148 in the South China Sea, about 2,300 km southwest of Site C0012, whereas Wade et al. (2011) are mainly based on Atlantic sites (ODP Sites 925 and

  7. The Cenozoic Diversity of Agglutinated Foraminifera - Evidence for a late Oligocene to early Miocene diversification event

    Science.gov (United States)

    Kaminski, Michael; Setoyama, Eiichi; Kender, Sev; Cetean, Claudia

    2014-05-01

    The agglutinated foraminifera are among the most abundant micro-organisms in the deep marine environment and have a diversity record extending back to the late Precambrian. We present an updated diversity curve for agglutinated foraminiferal genera based on the stratigraphic ranges of all the agglutinated genera recognized as valid in the classification of Kaminski (2014). The data set for this analysis is based on the stratigraphic ranges of agglutinated genera published in Foraminiferal Genera and their Classification, which has been subsequently updated based on published studies and our new observations. The mean standing diversity of agglutinated foraminiferal genera was compiled by counting the number of boundary crossers rather than the number of genera in each stage. In this study, we report the stratigraphic and geographical occurrence of a benthic foraminiferal diversification event that has previously received little attention. In the latest Oligocene to earliest Miocene a number of trochospiral agglutinated genera with alveolar or canaliculate walls first appeared in the fossil record. Our studies of late Oligocene of the Congo fan, offshore Angola (Kender et al., 2008; Cetean and Kaminski, 2011) have revealed a diverse assemblage that includes new taxa of deep-water agglutinated foraminifera. In a biostratigraphic study of the Miocene foraminiferal assemblages Kender et al. (2008) noted steadily increasing diversity and proportions of infaunal agglutinated foraminiferal morphotypes over the lower Miocene interval. The proportion of infaunal agglutinated foraminifera assigned to the order Textularida increased dramatically in the lower mid-Miocene, suggesting expansion of the oxygen minimum zone into deeper waters. In addition to the trochospiral alveolar genera, several species of Reticulophragmium and Cyclammina display rapid diversification into numerous separate lineages that are at present not reflected in our generic diversity record owing to

  8. Intertidal foraminifera (Protista) and carbon-nitrogen cycling: combined effects of temperature and diet quality

    Science.gov (United States)

    Wukovits, Julia; Enge, Annekatrin Julie; Oberrauch, Max; Watzka, Margarete; Wanek, Wolfgang; Heinz, Petra

    2017-04-01

    Benthic foraminifera (eukaryotic protists) are to a large extent acting as detrivores, feeding on microalgal detritus. Phytodetritus constitutes a main component of the intertidal carbon (C) and nitrogen (N) pool, thus making foraminifera important players in intertidal nutrient fluxes. These fluxes are strongly dependent on interactions between biotic and abiotic environmental factors, as e.g. the energetic value or the quality of phytodetritus that depends on environmental nutrient availability. Increased inorganic C concentrations in coastal water bodies (e.g. due to increased atmospheric CO2) can have a negative effect on the phytodetrital quality by increasing microalgal C:N ratios. Simultanous warming of the environment can cause increased metabolic rates of exposed heterotrophic organisms, like foraminifera. The combination of lower food quality and increased metabolic rates is supposed to cause cascading effects on organismic C cycling, potentially diminishing the role of detrivorous food as a C sink in marine food webs by increased discharge of excess C. In this study, the above described scenario was tested in laboratory feeding experiments on a common and abundant intertidal foraminiferal species (Haynesina germanica, collected in the German Wadden Sea). Two batches of artificially produced and dual isotope labeled (13C and 15N) chlorophyte detritus (1.5 gDW m-2) with different C:N ratios (5.5 and 7.6) and one batch of isotopically labelled diatom detritus (C:N 5.6) were fed under controlled conditions at three different temperatures. Results were extrapolated to the in situ abundance of live H. germanica individuals in the sampling area (sediment core data), to estimate the magnitude of the effect on an areal basis within the natural habitat. The study revealed significant, temperature induced variations in the carbon and nitrogen processing of H. germanica. The food source with an increased C:N ratio doubled the release of carbon from the H. germanica

  9. Benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Nigam, R.

    -wall-forming architecture (Loeblich and Tappan, 1987). This has largely to do with organization of calcite crystals in relation to the organic membrane that serves as a template for test secretion. A review of classification is presented in Sen Gupta (1999... less prone to diagenetic changes and degrade in a more arbitrary manner, indicating that their degradation is not only depend on test architecture, but also the physical/mechanical processes (Berkeley et al., 2009). There is a net, and species...

  10. Agglutinated foraminifera from the Northern Tarcău Nappe (Eastern Carpathians, Romania

    Directory of Open Access Journals (Sweden)

    Raluca Bindiu

    2011-10-01

    Full Text Available The Tarcău Nappe is the most important unit of the Carpathian flysch due to its size, stratigraphic, and tectonic complexity. Our purpose was to identify the major types of foraminifera assemblages in relation to the paleoenvironmental settings and their biostratigraphic potential. The identified assemblages are characteristic to the Cretaceous and Paleogene, consisting mostly of benthic agglutinated and, in lower proportions, benthic calcareous and planktonic species. Local abundances of Glomospira specimens allowed the correlation of the examined strata to the early Eocene “Glomospira event” described from the Carpathians in Poland, Morocco, and Labrador. Rzehakina fissistomata (Grzybowski identified at Palma makes possible the correlation of these deposits to the Paleocene Rzehakina fissistomata Zone. Paleoenvironmental conditions (depth, amount of oxygen, nutrients could be inferred based on specific assemblages and compared to the already described types of facies from the Carpathians.

  11. Heavy metal pollution monitoring with foraminifera in the estuaries of Nellore coast, East coast of India.

    Science.gov (United States)

    Sundara Raja Reddy, B C; Jayaraju, N; Sreenivasulu, G; Suresh, U; Reddy, A N

    2016-12-15

    A total of 112 bottom water and sediment samples collected at fixed stations in pre-monsoon and post-monsoon from four estuaries (Pennar, Uppateru, Swarnamukhi, and Kalangi) showed foraminiferal test abnormalities in heavy metal concentrations (Co, Cr, Cu, Fe, Mn, Ni, and Pb). Low diversity of fauna was due to the predominance of a limited number of opportunistic species capable of achieving high densities in adverse environmental conditions and the reduction in the number of species intolerant of such conditions. In this study, classification of 54 common species according to their distribution is presented. Approximately 15 species showed quite low diversities at stations 23-27 and 44-51. Because of the effect of heavy metal pollution in these estuaries, drastic changes in the number of species and diversity of foraminifera were observed. These changes in foraminiferal species and the increase in test abnormalities are proxies of environmental stress on the estuarine ecosystem.

  12. Nitrogen isotopic composition of planktonic foraminifera from the modern ocean and recent sediments

    Science.gov (United States)

    Ren, H.; Thunell, R.; Sigman, D. M.; Prokopenko, M. G.

    2010-12-01

    The nitrogen isotopic composition of the organic matter trapped within calcium carbonate matrix of planktonic foraminifera shells (foraminifera-bound δ15N, or FB-δ15N) is being measured in ocean sediment records to reconstruct past changes in the marine nitrogen cycle. Because of the multiple species of foraminifera and their differences in depth and trophic preference, FB-δ15N stands to have unprecedented richness as a paleoceanographic tool, but information on its generation and preservation is so far minimal. In this study, we report measurements of the δ15N of foraminiferal biomass from Sargasso Sea net tow material and shell-bound N from Cariaco Basin sediment traps and from shallow sediments collected in different open ocean regions. Comparison of the Sargasso Sea plankton tow data with FB-δ15N measurements in surface sediments from the low latitude N. Atlantic suggest that the δ15N of shell-bound organic material is similar to its biomass, at least for the symbiotic species, for which there is the most data. Our global data set of FB-δ15N from surface sediments shows a strong correlation between FB-δ15N and changes in the subsurface nitrate δ15N, which is the dominant source of new N to the euphotic zone in the oligotrophic regions. The three euphotic zone dwelling, symbiotic, and spinose species, G. ruber, G. sacculifer, and O. universa are very similar to the annual mean δ15N of the subsurface nitrate, whereas the deeper dwelling, non-spinose and/or asymbiotic forms are coherently higher in δ15N. In the Cariaco Basin sediment trap samples, the FB-δ15N of O. universa varies substantially, in some cases in step with bulk sediment trap δ15N variations, while the sub-euphotic zone dwelling, asymbiotic, and/or non-spinose species are generally higher in FB-δ15N and more stable through the time series. Euphotic zone dwellers such as O. universa probably prey dominantly on zooplankton and eukaryotic phytoplankton in the mixed layer down to the deep

  13. Burdigalian turbid water patch reef environment revealed by larger benthic foraminifera

    Science.gov (United States)

    Novak, V.; Renema, W.; Throughflow-project

    2012-04-01

    Ancient isolated patch reefs outcropping from siliciclastic sediments are a trademark for the Miocene carbonate deposits occurring in East Kalimantan, Indonesia. They develop in transitional shelf sediments deposited between deltaic and deep marine deposits (Allen and Chambers, 1998). The Batu Putih Limestone (Wilson, 2005) and similar outcrops in adjacent areas have been characterized as shallow water carbonates influenced by high siliciclastic input, showing low relief patch reefs in turbid waters. Larger benthic foraminifera (LBF) are excellent markers for biochronology and paleoenvironmental reconstruction. This study aims to reveal age and paleoenvironment of a shallow water carbonate patch reef developed in mixed depositional system by using LBF and microfacies analysis. The studied section is located near Bontang, East Kalimantan, and is approximately 80 m long and 12 m high. It is placed within Miocene sediments in the central part of the Kutai Basin. Patch reef and capping sediments were logged through eight transects along section and divided into nine different lithological units from which samples were collected. Thin sections and isolated specimens of larger benthic foraminifera were analyzed and recognized to species level (where possible) providing age and environmental information. Microfacies analysis of thin sections included carbonate classification (textural scheme of Dunham, 1962) and assemblage composition of LBF, algae and corals relative abundance. Three environmentally indicative groups of LBF were separated based on test morphology, habitat or living relatives (Hallock and Glenn, 1986). Analysed foraminifera assemblage suggests Burdigalian age (Tf1). With use of microfacies analysis nine successive lithological units were grouped into five facies types. Paleoenvironmental reconstruction of LBF fossil assemblage indicate two cycles of possible deepening recorded in the section. Based on high muddy matrix ratio in analyzed thin-sections we

  14. The Carbon and Oxygen Stable Isotopic Composition of Cultured Benthic Foraminifera (Bulimina aculeata).

    Science.gov (United States)

    McCorkle, D. C.; Bernhard, J. M.; Hintz, C. J.; Blanks, J. K.; Ostermann, D. R.; Shaw, T. J.; Chandler, G. T.

    2002-12-01

    To study the controls on benthic foraminiferal shell chemistry, live benthic foraminifera were collected from a 750 m site on the North Carolina continental margin. Mono-specific (Bulimina aculeata) and multi-species (B. aculeata, Discorbinella berthelotti, Cibicidoides pachyderma, Lenticulina sp., Uvigerina peregrina, Hoeglundina elegans) cultures were maintained for 4.5 months in an environmental chamber. Experimental microcosms contained a 1 mm layer of trace-metal free silica substrate, and were continuously flushed with water from a 1600 L seawater reservoir with known, constant temperature, δ18O(w), carbonate system chemistry and trace element concentrations. Each microcosm was seeded with 80-100 living foraminifera; B. aculeata was the most successful species in these cultures, with each microcosm producing hundreds of juvenile B. aculeata. We determined the stable isotopic composition of the calcite from the cultured B. aculeata, and compared these δ13C and δ18O values with the water chemistry of the microcosms, and with the shell chemistry of "free-range" B. aculeata collected and preserved from two sites on the NC and SC margin. The foraminiferal δ18O values were close to the expected δ18O of equilibrium calcite for both cultured and field B. aculeata (δ18O offsets of -0.2 +/- 0.1 ‰ and 0.0 +/- 0.1 ‰ , respectively). The δ13C values of cultured B. aculeata were 0.7 +/- 0.2 ‰ lower than microcosm dissolved inorganic carbon, with some evidence of smaller 13C depletions in older juveniles (larger specimens). The foram-bottom water δ13C offsets were larger for the field specimens (-0.8 ‰ at a 200 m site, and -1.4 ‰ at the 750 m site). These results suggest that the δ13C values of B. aculeata include both "vital" effects (the offset observed in cultured specimens) and microhabitat effects (the additional offset observed in field specimens).

  15. Trace element proxies for surface ocean conditions: A synthesis of culture calibrations with planktic foraminifera

    Science.gov (United States)

    Allen, Katherine A.; Hönisch, Bärbel; Eggins, Stephen M.; Haynes, Laura L.; Rosenthal, Yair; Yu, Jimin

    2016-11-01

    The trace element composition of planktic foraminiferal calcite provides a useful means of determining past surface ocean conditions. We have assembled the results of culture experiments for three species of symbiont-bearing planktic foraminifera, Globigerinoides ruber, Globigerinoides sacculifer, and Orbulina universa, and one symbiont-barren species, Globigerina bulloides, to evaluate their responses to temperature, salinity, pH, carbonate ion, and dissolved inorganic carbon (DIC) growth conditions. Trace element ratios (Li/Ca, B/Ca, Mg/Ca, Sr/Ca, Mn/Ca, Cd/Ca, Ba/Ca, Na/Ca, and U/Ca) were measured simultaneously on samples grown with the same culture techniques, which provides robust, relatable calibrations that may be used together in multi-proxy paleoceanographic studies. Our data confirm that temperature is the dominant control on foraminiferal Mg/Ca under the ranges of conditions studied and that the potential effects of salinity and CO32- on Mg/Ca of these tropical species across late Pleistocene glacial cycles are relatively small. Carbonate system experiments suggest that Sr/Ca may be useful for reconstructing large DIC changes. Na/Ca increases with salinity in G. ruber (pink), but not in G. sacculifer. As these emerging proxy relationships become more firmly established, the synthesis of multiple trace element ratios may help paleoceanographers isolate the effects of different environmental parameters in paleo records. Calcification rates (μg/day) vary among species and do not respond consistently to any experimental parameter. Comparison of our calcification rates with those observed in inorganic calcite precipitation experiments suggest that foraminifera calcify ∼100× more slowly than inorganic calcites grown in similar solutions. We suggest that calcification rate does not typically exert a dominant control on trace element partitioning in planktic foraminiferal calcite, though it may play a role for some elements under certain circumstances

  16. A decline in benthic foraminifera following the deepwater horizon event in the northeastern Gulf of Mexico.

    Science.gov (United States)

    Schwing, Patrick T; Romero, Isabel C; Brooks, Gregg R; Hastings, David W; Larson, Rebekka A; Hollander, David J

    2015-01-01

    Sediment cores were collected from three sites (1000-1200 m water depth) in the northeastern Gulf of Mexico from December 2010 to June 2011 to assess changes in benthic foraminiferal density related to the Deepwater Horizon (DWH) event (April-July 2010, 1500 m water depth). Short-lived radioisotope geochronologies (²¹⁰Pb, ²³⁴Th), organic geochemical assessments, and redox metal concentrations were determined to relate changes in sediment accumulation rate, contamination, and redox conditions with benthic foraminiferal density. Cores collected in December 2010 indicated a decline in density (80-93%). This decline was characterized by a decrease in benthic foraminiferal density and benthic foraminiferal accumulation rate (BFAR) in the surface 10 mm relative to the down-core mean in all benthic foraminifera, including the dominant genera (Bulimina spp., Uvigerina spp., and Cibicidoides spp.). Cores collected in February 2011 documented a site-specific response. There was evidence of a recovery in the benthic foraminiferal density and BFAR at the site closest to the wellhead (45 NM, NE). However, the site farther afield (60 NM, NE) recorded a continued decline in benthic foraminiferal density and BFAR down to near-zero values. This decline in benthic foraminiferal density occurred simultaneously with abrupt increases in sedimentary accumulation rates, polycyclic aromatic hydrocarbon (PAH) concentrations, and changes in redox conditions. Persistent reducing conditions (as many as 10 months after the event) in the surface of these core records were a possible cause of the decline. Another possible cause was the increase (2-3 times background) in PAH's, which are known to cause benthic foraminifera mortality and inhibit reproduction. Records of benthic foraminiferal density coupled with short-lived radionuclide geochronology and organic geochemistry were effective in quantifying the benthic response and will continue to be a valuable tool in determining the long

  17. A decline in benthic foraminifera following the deepwater horizon event in the northeastern Gulf of Mexico.

    Directory of Open Access Journals (Sweden)

    Patrick T Schwing

    Full Text Available Sediment cores were collected from three sites (1000-1200 m water depth in the northeastern Gulf of Mexico from December 2010 to June 2011 to assess changes in benthic foraminiferal density related to the Deepwater Horizon (DWH event (April-July 2010, 1500 m water depth. Short-lived radioisotope geochronologies (²¹⁰Pb, ²³⁴Th, organic geochemical assessments, and redox metal concentrations were determined to relate changes in sediment accumulation rate, contamination, and redox conditions with benthic foraminiferal density. Cores collected in December 2010 indicated a decline in density (80-93%. This decline was characterized by a decrease in benthic foraminiferal density and benthic foraminiferal accumulation rate (BFAR in the surface 10 mm relative to the down-core mean in all benthic foraminifera, including the dominant genera (Bulimina spp., Uvigerina spp., and Cibicidoides spp.. Cores collected in February 2011 documented a site-specific response. There was evidence of a recovery in the benthic foraminiferal density and BFAR at the site closest to the wellhead (45 NM, NE. However, the site farther afield (60 NM, NE recorded a continued decline in benthic foraminiferal density and BFAR down to near-zero values. This decline in benthic foraminiferal density occurred simultaneously with abrupt increases in sedimentary accumulation rates, polycyclic aromatic hydrocarbon (PAH concentrations, and changes in redox conditions. Persistent reducing conditions (as many as 10 months after the event in the surface of these core records were a possible cause of the decline. Another possible cause was the increase (2-3 times background in PAH's, which are known to cause benthic foraminifera mortality and inhibit reproduction. Records of benthic foraminiferal density coupled with short-lived radionuclide geochronology and organic geochemistry were effective in quantifying the benthic response and will continue to be a valuable tool in determining

  18. Combined effects of warming and ocean acidification on coral reef Foraminifera Marginopora vertebralis and Heterostegina depressa

    Science.gov (United States)

    Schmidt, Christiane; Kucera, Michal; Uthicke, Sven

    2014-09-01

    Warming and changes in ocean carbonate chemistry alter marine coastal ecosystems at an accelerating pace. The interaction between these stressors has been the subject of recent studies on reef organisms such as corals, bryozoa, molluscs, and crustose coralline algae. Here we investigated the combined effects of elevated sea surface temperatures and pCO2 on two species of photosymbiont-bearing coral reef Foraminifera: Heterostegina depressa (hosting diatoms) and Marginopora vertebralis (hosting dinoflagellates). The effects of single and combined stressors were studied by monitoring survivorship, growth, and physiological parameters, such as respiration, photochemistry (pulse amplitude modulation fluorometry and oxygen production), and chl a content. Specimens were exposed in flow-through aquaria for up to seven weeks to combinations of two pCO2 (~790 and ~490 µatm) and two temperature (28 and 31 °C) regimes. Elevated temperature had negative effects on the physiology of both species. Elevated pCO2 had negative effects on growth and apparent photosynthetic rate in H.depressa but a positive effect on effective quantum yield. With increasing pCO2, chl a content decreased in H. depressa and increased in M. vertebralis. The strongest stress responses were observed when the two stressors acted in combination. An interaction term was statistically significant in half of the measured parameters. Further exploration revealed that 75 % of these cases showed a synergistic (= larger than additive) interaction between the two stressors. These results indicate that negative physiological effects on photosymbiont-bearing coral reef Foraminifera are likely to be stronger under simultaneous acidification and temperature rise than what would be expected from the effect of each of the stressors individually.

  19. Benthic foraminifera baseline assemblages from a coastal nearshore reef complex on the central Great Barrier Reef

    Science.gov (United States)

    Johnson, Jamie; Perry, Chris; Smithers, Scott; Morgan, Kyle

    2016-04-01

    Declining water quality due to river catchment modification since European settlement (c. 1850 A.D.) represents a major threat to the health of coral reefs on Australia's Great Barrier Reef (GBR), particularly for those located in the coastal waters of the GBR's inner-shelf. These nearshore reefs are widely perceived to be most susceptible to declining water quality owing to their close proximity to river point sources. Despite this, nearshore reefs have been relatively poorly studied with the impacts and magnitudes of environmental degradation still remaining unclear. This is largely due to ongoing debates concerning the significance of increased sediment yields against naturally high background sedimentary regimes. Benthic foraminifera are increasingly used as tools for monitoring environmental and ecological change on coral reefs. On the GBR, the majority of studies have focussed on the spatial distributions of contemporary benthic foraminiferal assemblages. While baseline assemblages from other environments (e.g. inshore reefs and mangroves) have been described, very few records exist for nearshore reefs. Here, we present preliminary results from the first palaeoecological study of foraminiferal assemblages of nearshore reefs on the central GBR. Cores were recovered from the nearshore reef complex at Paluma Shoals using percussion techniques. Recovery was 100%, capturing the entire Holocene reef sequence of the selected reef structures. Radiocarbon dating and subsequent age-depth modelling techniques were used to identify reef sequences pre-dating European settlement. Benthic foraminifera assemblages were reconstructed from the identified sequences to establish pre-European ecological baselines with the aim of providing a record of foraminiferal distribution during vertical reef accretion and against which contemporary ecological change may be assessed.

  20. Proteins from the organic matrix of core-top and fossil planktonic foraminifera

    Science.gov (United States)

    Robbins, L. L.; Brew, K.

    1990-08-01

    Organic constituents isolated from the tests (shells) of six species of core-top planktonic foraminifera, ranging in age between 2 and 4 Ka BP, consist of a heterogeneous mixture of proteins and polypeptides. At least seven discrete polypeptides are present as indicated by reverse phase HPLC and by gel electrophoresis. High percentages of aspartic acid and glutamic acid characterize one class of protein, while glycine, serine, and alanine-rich proteins dominate in a second class. Similar HPLC Chromatographie elution profiles are observed for all species analyzed, varying only in intensity of the peaks and in amino acid composition from species to species. The approximate molecular weights of two major fossil proteins ranged between 50,000 and 70,000 daltons. A comparison of 2-4 and 300 Ka Bp samples shows that while most of the polypeptides are present in both samples, some acidic polypeptides are not present in the older sample. These data suggest that some of the acidic polypeptides may be more soluble than other fractions and are lost more quickly from the test. The remaining hydrophobic, possibly more insoluble, polypeptides may be preserved in much older specimens and may be useful in tracing phylogeny of the planktonic foraminifera. Amino acid analyses of total test extracts before and after dialysis demonstrate that some acidic amino acids, particularly aspartic acid, and possibly peptides less than 6000-8000 daltons are lost during dialysis. Although a large percentage of these components are undoubtedly from the original organic matrix, at this point adsorbed components cannot be ruled out. These data caution against the use of total amino acid compositions in biogeochemical studies.

  1. Lunar periodicity in the shell flux of planktonic foraminifera in the Gulf of Mexico

    Science.gov (United States)

    Jonkers, L.; Reynolds, C. E.; Richey, J.; Hall, I. R.

    2015-05-01

    Synchronised reproduction offers clear benefits to planktonic foraminifera - an important group of marine calcifiers - as it increases the chances of successful gamete fusion. Such synchrony requires tuning to an internal or external clock. Evidence exists for lunar reproductive cycles in some species, but its recognition in shell flux time series has proven difficult, raising questions about reproductive strategies. Using spectral analysis of a 4-year time series (mostly at weekly resolution) from the northern Gulf of Mexico, we show that the shell flux of Globorotalia menardii, Globigerinella siphonifera, Orbulina universa, Globigerinoides sacculifer, Globigerinoides ruber (both pink and white varieties), Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerinella calida and Globigerinita glutinata is characterised by lunar periodicity. However, the lunar rhythm is not present in all size fractions of each species and tends to be more dominant in the flux of larger shells, consistent with reproduction being more prevalent in larger specimens. Lunar periodicity is superimposed on longer term/seasonal changes in the shell fluxes, but accounts for a significant part of the variance in the fluxes. The amplitude of the lunar cycle increases roughly proportional with the magnitude of the flux, demonstrating that most of the population is indeed affected by lunar-phased synchronisation. In most species peak fluxes occur predominantly around, or just after, full moon. Only G. siphonifera and G. calida show a contrasting pattern with peaks concentrated around new moon. Although the exact cause of the synchronisation remains elusive, our data considerably increase the number of species for which lunar synchronised reproduction is reported and suggest that such reproductive behaviour is common in many species of planktonic foraminifera.

  2. A Decline in Benthic Foraminifera following the Deepwater Horizon Event in the Northeastern Gulf of Mexico

    Science.gov (United States)

    Schwing, Patrick T.; Romero, Isabel C.; Brooks, Gregg R.; Hastings, David W.; Larson, Rebekka A.; Hollander, David J.

    2015-01-01

    Sediment cores were collected from three sites (1000–1200 m water depth) in the northeastern Gulf of Mexico from December 2010 to June 2011 to assess changes in benthic foraminiferal density related to the Deepwater Horizon (DWH) event (April-July 2010, 1500 m water depth). Short-lived radioisotope geochronologies (210Pb, 234Th), organic geochemical assessments, and redox metal concentrations were determined to relate changes in sediment accumulation rate, contamination, and redox conditions with benthic foraminiferal density. Cores collected in December 2010 indicated a decline in density (80–93%). This decline was characterized by a decrease in benthic foraminiferal density and benthic foraminiferal accumulation rate (BFAR) in the surface 10 mm relative to the down-core mean in all benthic foraminifera, including the dominant genera (Bulimina spp., Uvigerina spp., and Cibicidoides spp.). Cores collected in February 2011 documented a site-specific response. There was evidence of a recovery in the benthic foraminiferal density and BFAR at the site closest to the wellhead (45 NM, NE). However, the site farther afield (60 NM, NE) recorded a continued decline in benthic foraminiferal density and BFAR down to near-zero values. This decline in benthic foraminiferal density occurred simultaneously with abrupt increases in sedimentary accumulation rates, polycyclic aromatic hydrocarbon (PAH) concentrations, and changes in redox conditions. Persistent reducing conditions (as many as 10 months after the event) in the surface of these core records were a possible cause of the decline. Another possible cause was the increase (2–3 times background) in PAH’s, which are known to cause benthic foraminifera mortality and inhibit reproduction. Records of benthic foraminiferal density coupled with short-lived radionuclide geochronology and organic geochemistry were effective in quantifying the benthic response and will continue to be a valuable tool in determining the long

  3. Lunar periodicity in the shell flux of some planktonic foraminifera in the Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    L. Jonkers

    2014-12-01

    Full Text Available Synchronised reproduction offers clear benefits to planktonic foraminifera – an important group of marine calcifiers – as it increases the chances of successful gamete fusion. Such synchrony requires tuning to an internal or external clock. Evidence exists for lunar reproductive cycles in some species, but its recognition in shell flux time series has proven difficult, raising questions about reproductive strategies. Using spectral analysis of a 6 year time series (mostly at weekly resolution from the northern Gulf of Mexico we show that the shell flux of Globorotalia menardii, Globigerinella siphonifera, Orbulina universa, Globigerinoides sacculifer and in Globigerinoides ruber (both pink and white varieties is characterised by lunar periodicity. The fluxes of Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerinella calida, Globorotalia crassaformis and Globigerinita glutinata do not show significant spectral power at the lunar frequency. If present, lunar periodicity is superimposed on longer term/seasonal changes in the shell fluxes, but accounts for a significant part of the variance in the fluxes. The amplitude of the lunar cycle increases roughly proportional with the magnitude of the flux, demonstrating that most of the population is indeed affected by lunar-phased synchronisation. Phasing of peak fluxes appears species-specific, with G. menardii, O. universa and G. sacculifer showing most peaks around the full moon and G. ruber one week later. Contrastingly, peaks G. siphonifera occur dominantly around new moon. Very limited literature exists on lunar phasing of foraminiferal export fluxes, but spatial differences in its presence may exist, corroborating the exogenous nature of lunar synchrony in planktonic foraminifera.

  4. Can abundance of protists be inferred from sequence data: a case study of foraminifera.

    Directory of Open Access Journals (Sweden)

    Alexandra A-T Weber

    Full Text Available Protists are key players in microbial communities, yet our understanding of their role in ecosystem functioning is seriously impeded by difficulties in identification of protistan species and their quantification. Current microscopy-based methods used for determining the abundance of protists are tedious and often show a low taxonomic resolution. Recent development of next-generation sequencing technologies offered a very powerful tool for studying the richness of protistan communities. Still, the relationship between abundance of species and number of sequences remains subjected to various technical and biological biases. Here, we test the impact of some of these biological biases on sequence abundance of SSU rRNA gene in foraminifera. First, we quantified the rDNA copy number and rRNA expression level of three species of foraminifera by qPCR. Then, we prepared five mock communities with these species, two in equal proportions and three with one species ten times more abundant. The libraries of rDNA and cDNA of the mock communities were constructed, Sanger sequenced and the sequence abundance was calculated. The initial species proportions were compared to the raw sequence proportions as well as to the sequence abundance normalized by rDNA copy number and rRNA expression level per species. Our results showed that without normalization, all sequence data differed significantly from the initial proportions. After normalization, the congruence between the number of sequences and number of specimens was much better. We conclude that without normalization, species abundance determination based on sequence data was not possible because of the effect of biological biases. Nevertheless, by taking into account the variation of rDNA copy number and rRNA expression level we were able to infer species abundance, suggesting that our approach can be successful in controlled conditions.

  5. Pleistocene oceanographie changes indicated by deep sea benthic foraminifera in the northern Indian Ocean

    Science.gov (United States)

    Rai, Ajai K.; Srinivasan, M. S.

    1994-12-01

    An attempt has been made to understand the Pleistocene bottom water history in response to the paleoclimatic changes in the northern Indian Ocean employing quantitative analyses of deep sea benthic foraminifera at the DSDP sites 219 and 238. Among the 150 benthic foraminifera recorded a few species show dominance with changing percent frequencies during most of the sequence. The dominant benthic foraminiferal assemblages suggest that most of the Pleistocene bottom waters at site 219 and Early Pleistocene bottom waters at site 238 are of North Indian Deep Water (NIDW) origin. However, Late Pleistocene assemblage at site 238 appears to be closely associated with a water mass intermediate between North Indian Deep Water (NIDW) and Antarctic Bottom Water (AABW). Uvigerina proboscidea is the most dominant benthic foraminiferal species present during the Pleistocene at both the sites. A marked increase in the relative abundance of U. proboscidea along with less diverse and equitable fauna during Early Pleistocene suggests a relative cooling, an intensified oceanic circulation and upwelling of nutrient rich bottom waters resulting in high surface productivity. At the same time, low sediment accumulation rate during Early Pleistocene reveals increased winnowing of the sediments possibly due to more corrosive and cold bottom waters. The Late Pleistocene in general, is marked by relatively warm and stable bottom waters as reflected by low abundance of U. proboscidea and more diverse and equitable benthic fauna. The lower depth range for the occurrence of Bulimina aculeate in the Indian Ocean is around 2300 m, similar to that of many other areas. B. aculeata also shows marked increase in its abundance near the Pliocene/Pleistocene boundary while a sudden decrease in the relative abundance of Stilostomella lepidula occurs close to the Early/Late Pleistocene boundary.

  6. Variability of the planktonic foraminifera community across the Eocene/Oligocene boundary, Fuente Caldera Section, Baetic Ranges (Spain)

    Science.gov (United States)

    Legarda-Lisarri, A.

    2013-12-01

    During the Eocene/Oligocene transition, in a massive extinction event that took place about 33.7 million years ago, the current high resolution study analyzes qualitatively and quantitatively the community structure of the planktonic foraminifera that were preserved in the hemipelagic sediments of the Tethys Sea. The sampled section of the Fuente Caldera column, located in the Baetic mountain ranges, spans a register of 396,551.7 years. Based in the identification of 27 species, that belong to 13 genera and 2 families of foraminifera, there have been found three biozones of Gonzalvo Zonation (Gonzalvo, 2002) in the studied stratigraphic interval: Turborotalia cocoaensis and Cribrohantkenina lazzarii Biozones (Rupelian), and Paragloborotalia increbescens (Priabonian). The planktonic foraminifera associations variability patterns are defined by paleoecologic indexes (diversity index, high and low latitude species index and planktonic and benthic foraminifera index), by geochemical proxies: δ18O and δ13C and by 'Q' Mode Factor Analysis. They prove that the deposition environment is outer platform and also, they suggest that the studied area in the Tethys Sea underwent many thermal pulses, during which some species extinct or appear. In the first extinction event the species Turborotalia cocoaensis and Turborotalia cunialensis became extinct. In the second one, Hantkenina alabamensis, Hantkenina brevispina, Cribrohantkenina lazzarii and Pseudohastigerina micra became extinct while a succession occured; Globigerina officinalis, Globoturborotalita anguliofficinalis and Tenuitellinata angustiumbilicata appeared. The cooling event that finished in the Lower Oligocene was the biggest of these pulses, which was extremely abrupt and corresponds to the Oi-1 event that was described by Miller (Miller, 1991). All this evidences that the planktonic foraminifera extinction in the Upper Eocene was a gradual and fast event, what is supported by the Factor Analysis application. Key

  7. Relationships between the distribution and stable isotopic composition of living benthic foraminifera and cold methane seep biogeochemistry in Monterey Bay, California

    Science.gov (United States)

    Rathburn, Anthony E.; PéRez, M. Elena; Martin, Jonathan B.; Day, Shelley A.; Mahn, Chris; Gieskes, Joris; Ziebis, Wiebke; Williams, David; Bahls, Amanda

    2003-12-01

    As part of an ongoing effort to explore the use of foraminifera as a means to assess modern and ancient methane release, we compared ambient pore water chemistry with the distribution and stable isotopic composition of living (rose Bengal stained) foraminifera in MBARI ROV Ventana tube cores taken from modern seepage areas (about 1000 m water depth) in Monterey Bay, California. Benthic foraminiferal isotopic differences between sites clearly indicate that methane-influenced pore waters affect foraminiferal distributions and carbonate isotope geochemistry. Carbon isotope signatures of living benthic foraminifera did not conform to the very negative (-30 to -48‰), methane-influenced carbon isotope values of the pore waters they live in. Instead, the influence of methane seep pore waters was reflected in the greater range and carbon isotopic variability of living seep foraminifera compared with published δ13C values of foraminifera living in nonseep habitats. It is not clear what relative influences biological, ecological, and physical factors have on the carbon isotopic signatures observed in seep foraminifera. Substantial carbon isotope differences can exist between individuals of the same seep species. For instance, δ13C values of living Globobulimina pacifica varied by as much as 2.9‰ between seeps within 8 km of each other, whereas δ13C values of living Uvigerina peregrina varied by as much as 1.95‰ within the same seep. Provided there is no diagenetic alteration of the test carbonate, isotopic results of individual seep foraminifera support the hypothesis that foraminifera can be used to assess past and present methane seepage.

  8. Ecological modeling of planktonic foraminifera to facilitate climate model-proxy reconcilliation during the mid-Piacenzian

    Science.gov (United States)

    Jacobs, P.; Dowsett, H. J.; de Mutsert, K.

    2016-12-01

    Significant advancements have been made in reconciling reconstructed paleoclimatic conditions from the mid-Piacenzian Warm Period (mPWP) with climate models driven by mPWP boundary conditions. Nevertheless, some model-proxy discrepancies (e.g. high latitude North Atlantic, the California Current) remain unresolved. In order to explore potential causes for these disagreements in foraminifera faunal assemblage reconstructions such as the Pliocene Research, Interpretation and Synoptic Mapping (PRISM), key planktonic foraminfera species models are created using modern, "core top" presence information calibrated with and validated against oceanographic data from the World Ocean Atlas (WOA13). To ensure robustness to the underlying statistical model choice, multiple methods (e.g. multilayer perceptron neural networks, Mahalanobis distance, logistic regression, and maximum entropy) are employed. The resulting foraminifera models are suitable for exploring factors leading to model-proxy disagreements (e.g. through iteratively imposed changes in climate model variables until agreement is reached).

  9. GLOMOMIDIELLA N. GEN. (FORAMINIFERA, MILIOLATA, NEODISCIDAE: A NEW GENUS FROM THE LATE GUADALUPIAN-LOPINGIAN OF HYDRA ISLAND (GREECE

    Directory of Open Access Journals (Sweden)

    DANIEL VACHARD

    2008-11-01

    Full Text Available A new genus of Foraminifera (Miliolata, Cornuspiroidea, Neodiscidae is erected from the late Guadalupian (Capitanian = Midian to Lopingian sedimentary succession of the island of Hydra (Greece. It represents an important phylogenetic form, probably at the origin of several genera (or subfamilies of the authors that became relatively widespread during the Lopingian (Late Permian. Glomomidiella n. gen. is characterized by an entirely glomospiral coiling and rudimentary pseudoseptation. 

  10. Foraminifera in surface sediments of Mandovi River Estuary: Indicators for mining pollution and high sea stand in Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Panchang, R.; Banerjee, P.

    of mieofauna size, are ex- tremely sensitive to the slightest change in marine environ- mental conditions. They have good preservation and fossil- ization potential and thus have been used extensively in pol- lution studies all over the world (ALVE, 1995... and deposited in shallow-water areas. Though it is not uncommon for fossil foraminifera to be eroded, transported, and deposited in the modern depository area, this is the first time that such a situation has been encountered in the present study area...

  11. Pleistocene-Holocene lower bathyal benthic foraminifera: A pilot study in Keathley Canyon, northwestern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Jones, M.J. (Louisiana State Univ., Baton Rouge (United States))

    1991-03-01

    Recent work on the shelf and upper slope have linked the distribution of benthic foraminifera to the presence of several Gulf of Mexico water masses. A pilot study consisting of three piston cores from lower bathyal depths (1,308 m, 1,543 m, 1,815 m) was undertaken to examine the distribution of benthic foraminifera across the Pleistocene-Holocene boundary and at several depths within the lower slope environment. The primary objective of this study was to test the hypothesis that abundance variations of benthic foraminifera can be used to refine the bathymetric zonation of deep Gulf of Mexico depositional environments based on their water mass associations. Preliminary results from this study support this hypothesis by showing a distinct variation in benthic foraminiferal abundances between the shallower cores (1,308 m, 1,543 m) and the deeper core (1,815 m). The cores from 1,308 m and 1,543 m contain a fauna that exhibits a moderate abundance (ca. 10-15%) of several species: Bolivina lowmania, Bulimina aculeata, Cassidulina subglobosa, Gyroidina soldanii and Oridorsalis spp., while the core from 1815 m contains a fauna strongly dominated (25-60%) by two species: Eponides turgidus and Nuttallides decorata. Abundance variations downcore or across the Pleistocene-Holocene boundary are subtle but present nonetheless. The preliminary results from this study suggest that the distribution of deep Gulf of Mexico benthic foraminifera may be related to the distribution of water masses comprising the deep gulf and that further bathymetric refinement of the lower slope may be possible.

  12. Modern agglutinated Foraminifera from the Hovgaard Ridge, Fram Strait, west of Spitzbergen: Evidence for a deep bottom current

    OpenAIRE

    Kaminski, M.A.; Niessen, Frank; Bazhenova, E.; De La Guardia, L C.; Coakley, B.; de Vernal, A.; Eagles, Graeme; Eisermann, Hannes; Forwick, Matthias; Gebhardt, Catalina; Geissler, Wolfram; Horner, T.; Jensen, Laura; Jin, H.; Jokat, W.

    2015-01-01

    Deep-water agglutinated foraminifera on the crest of the Hovgaard Ridge, west of Spitsbergen, consist mostly of large tubular astrorhizids. At a boxcore station collected from the crest of Hovgaard Ridge at a water depth of 1169 m, the sediment surface was covered with patches of large (1 mm diameter) tubular forms, be longing mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubular species consisted mainly of ...

  13. Effects of radionuclides on the recent foraminifera from the clastic sediments of the Çanakkale Strait-Turkey

    Science.gov (United States)

    Yümün, Zeki Ünal; Kam, Erol

    2017-07-01

    The radionuclides that cause radioactivity accumulate in the sediments as they descend to the seabed, similar to heavy metals. As radionuclides are present on the surface of the sediment or within the sediment, marine benthic foraminifera can be affected by the radioactive pollution. In this study, the habitat of benthic foraminifera was evaluated for radioactive pollution in the Çanakkale Strait, which constitutes the passage of the Marmara Sea and the Aegean Sea. In 2015, seven core samples and one drilling sample were taken from the shallow marine environment, which is the habitat of benthic foraminifera, in the Çanakkale Strait. Locations of the core samples were specifically selected to be pollution indicators in port areas. Gamma spectrometric analysis was used to determine the radioactivity properties of sediments. The radionuclide concentration activity values in the sediment samples obtained from the locations were Cs-137: values were compared with the Turkish Atomic Energy Agency (TAEK) and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) data and environmental analysis was carried out. The Ra-226 series, the Th-232 series and the K-40 radionuclides accumulate naturally and increase continuously due to anthropogenic pollution. Although the Ra-226 values obtained in the study areas remained within normal limits according to UNSCEAR values, the K-40 and Th-232 series values were observed to be high in almost all locations. The values of Cs-137 were found to be maximum 20 in Çanakkale Dere Port and they were parallel to the values in the other places. In the study, 13 genera and 20 species were identified from core and drilling samples. The number of foraminifera species and individuals obtained at locations with high pollution was very low compared to those in non-polluted zones.

  14. Benthic foraminifera (Protista) as indicators of metal pollution in areas of historic mining: examples from southwest England

    Science.gov (United States)

    Hart, Malcolm; Smart, Christopher

    2016-04-01

    Southwest England has been, from Roman times, an important mining area supplying a range of important metals, including copper, tin, tungsten, arsenic, zinc, silver, etc. This mining activity virtually disappeared in the twentieth century, although one tungsten mine near Plymouth has recently re-opened. Large areas of Cornwall and West Devon are now inscribed as the 'Cornish Mining World Heritage Site' on the cultural list of UNESCO. Many of the old mines with their spoil heaps and tailings dams are now protected and, together with the mineral-rich local geology, provide many catchments with on-going metal pollution. In January 1992, after a period of prolonged, heavy rainfall Wheal Jane mine flooded and discharged heavily polluted, acidic, water into Restonguet Creek and the Fal Estuary. This event provided the setting for a detailed investigation of the immediate impact of the pollution and the resulting environmental improvements caused by engineering interventions and natural re-adjustment. Benthic foraminifera disappeared from Restronguet Creek for a number of years and while there is now an abundant, though low diversity, estuarine assemblage of foraminifera living in the creek there are still high levels (metal elements in the catchments that supply these estuaries, are sufficient to maintain these levels of deformity in the long term. OLUGBODE, O.I., HART, M.B. & STUBBLES, S.J. 2005. Foraminifera from Restronguet Creek: monitoring recovery from the Wheal Jane pollution incident. Geoscience in south-west England, 11, 82-92.

  15. Benthic Foraminifera and Bacterial Activity as a Proxy for Environmental Characterization in Potengi Estuary, Rio Grande do Norte, Brazil

    Directory of Open Access Journals (Sweden)

    Frederico S. da Silva

    2010-01-01

    Full Text Available The aim of this study was to identify possible zonation patterns and assess the environmental impact on the Potengi River Estuary, Rio Grande do Norte State, through the distribution of benthic foraminifera associated to bacterial activity and abiotic parameters. Six sediment samples were collected from locations that presented clear signs of pollution. The environment was predominantly anaerobic and fermentation occurred at all sites. Forty-two species of foraminifera were identified. The dominant species were Ammonia tepida and Arenoparrella mexicana, which are known to be opportunistic, and able to adapt to rapidly changing conditions. CCA analyses showed that salinity and organic matter, followed by bacterial carbon, were more strongly linked to organism distribution in the Potengi River Estuary. Dissolved oxygen concentration, temperature and total organic matter were higher at the estuary mouth than at the other sites, creating favorable conditions for foraminiferal growth and allowing the faunistic succession on the upper estuary. As foraminifera assemblages when associated to environmental parameters can be used as efficient proxies for environmental diagnosis, these results suggest that the Potengi Estuary is under great stress from the surrounding urban development.

  16. Marine ecology conditions at Weda Bay, North Maluku based on statistical analysis on distribution of recent foraminifera

    Directory of Open Access Journals (Sweden)

    Kurniasih Anis

    2017-01-01

    Full Text Available Analysis of foraminifera in geology,usually being used to find the age of rocks/ sediments and depositional environment. In this study, recent foraminifera was used not only to determinethe sedimentary environment,but also to estimate the ecological condition of the water through a statistical approach.Analysis was performed quantitatively in 10 surface seabed sediment samples in Weda Bay North Maluku. The analysis includes dominance (Sympson Index, diversity and evenness (Shannon Index, and the ratio of planktonic -benthic. The results were shown in the plotting diagram of M-R-T (Miliolid-Rotalid-Textularid to determine the depositional environment. Quantitative analysis was performed using Past software (paleontological version Statistic 1:29.The analysis result showed there was no domination of certain taxon with a moderate degree of evenness and stable communities and considerably a moderate diversity. The results of this analysis indicated that research area had a stable water conditions with the optimum level of carbonate content, oxygen supply, salinity, and temperature. The ratio of planktonic and benthic indicate the relative depth, which was deeper the water increased the percentage of planktonic foraminifera. Based on M-R-T diagram showed the distribution of sediment deposited on exposed carbonate (carbonate platform environment with normal saline.

  17. Effect of ocean acidification on the benthic foraminifera Ammonia sp. is caused by a decrease in carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. Keul

    2013-10-01

    Full Text Available About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA. Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic calcium carbonate in the open oceans. We have compiled the state of the art literature on OA effects on foraminifera, because the majority of OA research on this group was published within the last three years. Disparate responses of this important group of marine calcifiers to OA were reported, highlighting the importance of a process-based understanding of OA effects on foraminifera. We cultured the benthic foraminifer Ammonia sp. under a range of carbonate chemistry manipulation treatments to identify the parameter of the carbonate system causing the observed effects. This parameter identification is the first step towards a process-based understanding. We argue that [CO32−] is the parameter affecting foraminiferal size-normalized weights (SNWs and growth rates. Based on the presented data, we can confirm the strong potential of Ammonia sp. foraminiferal SNW as a [CO32−] proxy.

  18. Effect of ocean acidification on the benthic foraminifera Ammonia sp. is caused by a decrease in carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    J. Bijma

    2013-01-01

    Full Text Available About 30% of the anthropogenically released CO2 is taken up by the oceans, which causes surface ocean pH to decrease and is commonly referred to as Ocean Acidification (OA. Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50% of biogenic calcium carbonate in the open oceans. We have compiled the state of the art of OA effects on foraminifera, because the majority of OA research on this group was published within the last 3 yr. Disparate responses of this important group of marine calcifiers to OA were reported, highlighting the importance of a process based understanding of OA effects on foraminifera. The benthic foraminifer Ammonia sp. was cultured using two carbonate chemistry manipulation approaches: While pH and carbonate ions where varied in one, pH was kept constant in the other while carbonate ion concentration varied. This allows the identification of teh parameter of the parameter of the carbonate system causing observed effects. This parameter identification is the first step towards a process based understanding. We argue that [CO32−] is the parameter affecting foraminiferal size normalized weights (SNW and growth rates and based on the presented data we can confirm the strong potential of foraminiferal SNW as a [CO32−] proxy.

  19. Global analysis of seasonality in the shell flux of extant planktonic Foraminifera

    Science.gov (United States)

    Jonkers, L.; Kučera, M.

    2015-04-01

    Shell fluxes of planktonic Foraminifera species vary intra-annually in a pattern that appears to follow the seasonal cycle. However, the variation in the timing and prominence of seasonal flux maxima in space and among species remains poorly constrained. Thus, although changing seasonality may result in a flux-weighted temperature offset of more than 5° C within a species, this effect is often ignored in the interpretation of Foraminifera-based paleoceanographic records. To address this issue we present an analysis of the intra-annual pattern of shell flux variability in 37 globally distributed time series. The existence of a seasonal component in flux variability was objectively characterised using periodic regression. This analysis yielded estimates of the number, timing and prominence of seasonal flux maxima. Over 80% of the flux series across all species showed a statistically significant periodic component, indicating that a considerable part of the intra-annual flux variability is predictable. Temperature appears to be a powerful predictor of flux seasonality, but its effect differs among species. Three different modes of seasonality are distinguishable. Tropical and subtropical species (Globigerinoides ruber (white and pink varieties), Neogloboquadrina dutertrei, Globigerinoides sacculifer, Orbulina universa, Globigerinella siphonifera, Pulleniatina obliquiloculata, Globorotalia menardii, Globoturborotalita rubescens, Globoturborotalita tenella and Globigerinoides conglobatus) appear to have a less predictable flux pattern, with random peak timing in warm waters. In colder waters, seasonality is more prevalent: peak fluxes occur shortly after summer temperature maxima and peak prominence increases. This tendency is stronger in species with a narrower temperature range, implying that warm-adapted species find it increasingly difficult to reproduce outside their optimum temperature range and that, with decreasing mean temperature, their flux is progressively

  20. An endemic post-CTB Pseudorhapydionina (foraminifera) from the Pyrenean palaeobioprovince

    Science.gov (United States)

    Consorti, Lorenzo; Caus, Esmeralda

    2015-04-01

    The genus Pseudorhapydionina and its allies are porcelaneous ranging from cylindrical to fan-shaped larger benthic foraminifera (LBF), with planispiral-involute chamber arrangement becoming uncoiled or flabelliform-to-cyclical in adult stages. The apertural face has pierced by multiple cribate openings. The marginal chamber lumen is partially subdivided by subepidermal plates, while the central area might or might not present pillars. They characterise latest Albian?-Cenomanian (Middle Cretaceous Global Community Maturation Cycle) shallow-water carbonate deposits from Mexico (Caribbean LBF palaeobioprovince) to the Iberian Peninsula, Italy, Greece, Middle East and North of Africa (western, central and eastern Tethyan LBF palaeobioprovinces, respectively), but they have never been found in the Pyrenean palaeobioprovince. It is widely accepted that pseudorhapydioninids and other groups of larger benthic foraminifera, such as alveolinids, with an extreme or moderate K-strategy of life disappear near the Cenomanian-Turonian boundary (CTB), when a major extinction took place in both shallow and deep marine realms. However, it seems that some Cenomanian genera, such as Cyclolina, Cyclopsinella, Dicyclina, Cuneolina, and Rotorbinella, escaped from the extinction during the CTB oceanic anoxic event (OAE2 or Bonarelli Event), but more detailed studies are needed to confirm if taxa at both sides of the boundary are actually related. New studies in the South-central Pyrenees have shown the occurrence of Pseudorhapydionina morphotypes in the shallow-water deposits of the uppermost part of the La Cova limestone, which age constrained by strontium isotope stratigraphy (SIS) is lower Santonian (Late Cretaceous GCMC). These pseudorhapydioninid morphotypes co-occur in the levels containing Martiguesia cyclamminiformis, Ramirezella montsechiensis, Lacazina pyrenaica, Pseudolacazina loeblichii, Palandroxina taxyae, Hellenalveolina tappanae, Iberorotalia reicheli, Calcarinella schaubi

  1. Benthic foraminifera from the Arabian Sea oxygen minimum zone: towards a paleo-oxygenation proxy.

    Science.gov (United States)

    Clemence, Caulle; Meryem, Mojtahid; Karoliina, Koho; Andy, Gooday; Gert-Jan, Reichart; Gerhard, Schmiedl; Frans, Jorissen

    2014-05-01

    Benthic foraminifera from the Arabian Sea oxygen minimum zone: towards a paleo-oxygenation proxy. C. Caulle1, M. Mojtahid1, K. Koho2,3, A. Gooday4, G. J. Reichart2,3, G. Schmiedl5, F. Jorissen1 1UMR CNRS 6112 LPG-BIAF, University of Angers, 2 bd Lavoisier, 49045 Angers Cedex 2Utrecht University, Faculty of Geosciences, Department of Earth Sciences, Budapestlaan 4, 3584 CD Utrecht, The Netherlands 3Royal Netherland Institute for Sea Research (Royal NIOZ), Landsdiep 4, 1797 SZ 't Horntje (Texel) 4Southampton Oceanography Centre, Empress Dock, European Way, Southampton SO14 3ZH, UK 5Department of Geosciences, University of Hamburg, Bundesstraße 55, 20146 Hamburg, Germany The thermohaline circulation oxygenates the deep ocean sediment and therefore enables aerobic life on the sea-floor. In the past, interruption of this deep water formation occurred several times causing hypoxic to anoxic conditions on the sea-floor leading to major ecological turnover. A better understanding of the interaction between climate and bottom water oxygenation is therefore essential in order to predict future oceanic responses. Presently, permanent (stable over decadal timescale) low-oxygen conditions occur naturally at mid-water depths in the northern Indian Ocean (Arabian Sea). Oxygen Minimum Zones (OMZ) are key areas to understand the hypoxic-anoxic events and their impact on the benthic ecosystem. In this context, a good knowledge of the ecology and life cycle adaptations of the benthic foraminiferal assemblages living in these low oxygen areas is essential. A series of multicores were recovered from three transects showing an oxygen gradient across the OMZ: the Murray Ridge, the Oman margin and the Indian margin. The stations located at the same depths showed slightly different oxygen concentrations and large differences in organic matter content. These differences are mainly related to the geographic location in the Arabian Sea. We investigated at these stations live and dead benthic

  2. The Effects of Carbon Dioxide Sequestration on Deep-sea Foraminifera in two California Margin Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ricketts, Erin R

    2006-01-01

    ABSTRACT Deep-sea sequestration of CO2 is being considered as a possible mitigation tool to decrease atmospheric CO2 concentrations and its associated negative effects. This study is the first to investigate potential effects of liquid carbon dioxide (CO2) injection on deep-sea foraminiferal assemblages. Foraminifera are ideal for this ecological impact investigation because of differing test composition (calcareous and non-calcareous) and thickness, and diverse epifaunal and infaunal depth preferences. The experiment was conducted August-September 2003, at 3600m off the coast of Monterey Bay, California, aboard the R/V Western Flyer using the ROV Tiburon. The pH of the site was monitored throughout the experiment by Seabird CTDs. Sediment push-cores were collected (both from the experimental and control sites) and stained to distinguish live (stained) from dead (unstained) individuals. Effects of CO2 injection on assemblages have been tracked both vertically (to 10cm depth below sea floor) and horizontally (up to 10m from CO2 injection sites), as well as between live and dead individuals. Within the corrals and underlying sediments severe pH changes (to near 4.0) were seen while over the experimental area small average reductions in ocean pH (-0.05 units) and large episodic excursions (-1.7 units) were measured resulting from CO2 injection. Exposure to this gradient of low pH caused increased mortality and dissolution of calcareous forms within corrals, as far as 5m from the injection site, and to at least 10cm depth in the sediments. This experiment revealed several major effects of CO2 injection on foraminiferal assemblages in surficial sediments: 1) total number of foraminifera in a sample decreases; 2) foraminiferal species richness decreases in both stained and unstained specimens; and 3) percentage of stained (live) forms increases. Down-core trends (to 10cm below sea floor) have revealed: 1) percent agglutinated forms decline and calcareous forms increase

  3. Foraminifera in elevated Bermudian caves provide further evidence for +21 m eustatic sea level during Marine Isotope Stage 11

    Science.gov (United States)

    van Hengstum, Peter J.; Scott, David B.; Javaux, Emmanuelle J.

    2009-09-01

    Two hypotheses have been proposed to explain the origin of marine isotope stage (MIS) 11 deposits in small Bermudian caves at +21 m above modern sea level: (1) a +21 m MIS 11 eustatic sea-level highstand, and (2) a MIS 11 mega-tsunami event. Importantly, the foraminifera reported in these caves have yet to be critically evaluated within a framework of coastal cave environments. After statistically comparing foraminifera in modern Bermudian littoral caves and the MIS 11 Calonectris Pocket A (+21 m cave) to the largest available database of Bermudian coastal foraminifera, the assemblages found in modern littoral caves - and Calonectris Pocket A - cannot be statistically differentiated from lagoons. This observation is expected considering littoral caves are simply sheltered extensions of a lagoon environment in the littoral zone, where typical coastal processes (waves, storms) homogenize and rework lagoonal, reefal, and occasional planktic taxa. Fossil protoconchs of the Bermudian cave stygobite Caecum caverna were also associated with the foraminifera. These results indicate that the MIS 11 Bermudian caves are fossil littoral caves (breached flank margin caves), where the total MIS 11 microfossil assemblage is preserving a signature of coeval sea level at +21 m. Brackish foraminifera ( Polysaccammina, Pseudothurammina) and anchialine gastropods (˜95%, >300 individuals) indicate a brackish anchialine habitat developed in the elevated caves after the prolonged littoral environmental phase. The onset of sea-level regression following the +21 m highstand would first lower the ancient brackish Ghyben-Herzberg lens (<0.5 m) and flood the cave with brackish water, followed by drainage of the cave to create a permanent vadose environment. These interpretations of the MIS 11 microfossils (considering both taphonomy and paleoecology) are congruent with the micropaleontological, hydrogeological and physical mechanisms influencing modern Bermudian coastal cave environments. In

  4. Carbon isotopes of benthic foraminifera associated with methane seeps in Four-Way Closure Ridge, offshore southwestern Taiwan

    Science.gov (United States)

    Wang, W. R.; Wei, K. Y.; Mii, H. S.; Lin, Y. S.; Huang, J. J.; Wang, P. L.; Lin, A. T.

    2015-12-01

    Release of large amounts of methane from marine gas hydrate reservoirs has been considered as a possible trigger of climate change, which can be recorded by the variation of carbon isotopes (δ13C) of the benthic foraminifera. In modern analogs, previous studies have suggested that δ13C becomes more negative when influenced by methane seeps. However, values of δ13C of benthic foraminifera might vary with different species and sedimentary settings in different regions. Seismic profiles in offshore southwestern Taiwan show the existence of Bottom Simulating Reflector (BSR) in the region, indicative of gas hydrate reservoirs. Various methane seepages have been found, and they are suspected to be related to the gas hydrates buried underneath. A better understanding of the δ13C signals of benthic foraminifera near the methane seepages can further clarify the origin of the methane and to evaluate it as a proxy of methane release for the geologic past. We have analyzed δ13C of benthic foraminifera Uvigerina proboscidea (150-250 mm) in the topmost 15 cm sediments in five marine cores (OR1-1092-WFWC-1, OR1-1092-WFWC-4, OR1-1092-WFWC-6, OR3-1806-C5-2 and OR3-1806-C10) collected from the Four-Way Closure Ridge in offshore southwestern Taiwan (water depth from 1330 to 1580 m). Our results show that δ13C values of U. proboscidea range from -0.98‰ to -6.21‰ (VPDB) for core OR3-1806-C5-2, which is considered as a seeps-influenced site. On the other hand, δ13C values of U. proboscidea from the background sites range from -0.40‰ to -1.00‰. The difference between the methane seep-affected and the background sites is in the range of 0.00‰ to 5.01‰, comparable to those documented in previous studies in other areas. The significant negative excursion in carbon isotopes in the seep site foraminifera is likely caused by incorporation of light inorganic carbon generated by methanotrophy in the system.

  5. Agglutinated Foraminifera indicate a deep bottom current over the Hovgaard Ridge, West of Spitsbergen

    Science.gov (United States)

    Kaminski, Michael; Frank, Niessen

    2015-04-01

    The Hovgård Ridge is situated in Fram Strait, west of Spitsbergen. The ridge either represents a submerged fragment of continental crust or an upwarped fragmant of ocean crust within the Fram Strait. Its crest rises to a water depth of approx. 1170 m. During Expedition 87 of the Icebreaker POLARSTERN in August 2014, a sediment-echosounding profile was recorded and a boxcore station was collected from the crest of Hovgård Ridge at 1169 m water depth. The surficial sediment at this station consists of dark yellowish brown pebbly-sandy mud with a minor admixture of biogenic components in the coarse fraction. Patches of large tubular foraminifera and isolated pebbles were clearly visible on the sediment surface. The sediment surface of the boxcore was covered with patches of large (>1 mm diameter) large tubular astrorhizids belonging mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubular species consist mainly of opportunistic forms such as Psammosphaera and Reophax. The presence of large suspension-feeding tubular genera as well as opportunistic forms, as well as sediment winnowing, point to the presence of a deep current at this locality that is strong enough to disturb the benthic fauna. This is confirmed by data obtained from sediment echosounding, which exhibit lateral variation of relative sedimentation rates within the Pleistocene sedimentary drape covering the ridge indicative of winnowing in a south-easterly direction.

  6. Environmental Quality Assessment of Bizerte Lagoon (Tunisia Using Living Foraminifera Assemblages and a Multiproxy Approach.

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    Maria Virgínia Alves Martins

    Full Text Available This study investigated the environmental quality of the Bizerte Lagoon (Tunisia through an integrated approach that combined environmental, biogeochemical, and living benthic foraminiferal analyses. Specifically, we analyzed the physicochemical parameters of the water and sediment. The textural, mineralogical, and geochemical characteristics of the sediment, including total organic carbon, total nitrogen, simultaneously extracted metals (SEM, acid volatile sulfides (AVS, chlorophyll a, CaCO3, and changes in bacterial populations and carbon isotopes were measured. The SEM/AVS values indicated the presence of relatively high concentrations of toxic metals in only some areas. Foraminiferal assemblages were dominated by species such as A. parkinsoniana (20-91%, Bolivina striatula (<40%, Hopkinsina atlantica (<17%, and Bolivina ordinaria (<15% that cannot be considered typical of impacted coastal lagoons both in Mediterranean and northeast Atlantic regions. The results of this work suggest that Bizerte Lagoon is a unique setting. This lagoon is populated by typical marine species that invaded this ecosystem, attracted not only by the prevailing favorable environmental conditions but also by the abundance and quality of food. The results indicate that the metal pollution found in some areas have a negative impact on the assemblages of foraminifera. At present, however, this negative impact is not highly alarming.

  7. Phanerozoic size history of the foraminifera: Implications for environmental and biological controls on macroevolutionary trends

    Science.gov (United States)

    Payne, J.; Jost, A. B.; Cummins, R.; Tachiki, N.; Ingram, K.

    2009-12-01

    Size is among the most important ecological characteristics of any organism, correlating with a wide variety of traits from metabolic rate to generation time. Although there have been numerous studies of body size evolution in the fossil record, few have spanned multiple geological eras. Thus, the effect of environmental changes occurring on Wilson-cycle timescales (hundreds of millions of years) on the evolution of size remains poorly understood. We compiled a comprehensive genus-level size database for benthic foraminifers through Phanerozoic time. We find that the average size of calcareous benthic foraminifers increased gradually through the Late Paleozoic, reaching local maxima in mean and maximum size during the Early Permian. Sizes decreased to a relative minimum during the Early Triassic before increasing gradually to a second local maximum in the Late Cretaceous (for maximum size) and early Paleogene (for mean size). Close resemblance of trends in mean size to trends in atmospheric oxygen concentrations suggest either oxygen has been an important driver of size evolution or the two variables share a common control. Superimposed on these long-term trends are signatures of the major extinction events. Four of the five largest drops in mean size occur in association with the Middle Permian (Guadalupian), end-Permian, end-Triassic, and end-Cretaceous mass extinctions. Thus, the Phanerozoic size history of benthic foraminifera appears to have been driven primarily by long-term and short-term environmental change.

  8. Environmental Quality Assessment of Bizerte Lagoon (Tunisia) Using Living Foraminifera Assemblages and a Multiproxy Approach

    Science.gov (United States)

    Alves Martins, Maria Virgínia; Zaaboub, Noureddine; Aleya, Lotfi; Frontalini, Fabrizio; Pereira, Egberto; Miranda, Paulo; Mane, Miguel; Rocha, Fernando; Laut, Lazaro; El Bour, Monia

    2015-01-01

    This study investigated the environmental quality of the Bizerte Lagoon (Tunisia) through an integrated approach that combined environmental, biogeochemical, and living benthic foraminiferal analyses. Specifically, we analyzed the physicochemical parameters of the water and sediment. The textural, mineralogical, and geochemical characteristics of the sediment, including total organic carbon, total nitrogen, simultaneously extracted metals (SEM), acid volatile sulfides (AVS), chlorophyll a, CaCO3, and changes in bacterial populations and carbon isotopes were measured. The SEM/AVS values indicated the presence of relatively high concentrations of toxic metals in only some areas. Foraminiferal assemblages were dominated by species such as A. parkinsoniana (20–91%), Bolivina striatula (<40%), Hopkinsina atlantica (<17%), and Bolivina ordinaria (<15%) that cannot be considered typical of impacted coastal lagoons both in Mediterranean and northeast Atlantic regions. The results of this work suggest that Bizerte Lagoon is a unique setting. This lagoon is populated by typical marine species that invaded this ecosystem, attracted not only by the prevailing favorable environmental conditions but also by the abundance and quality of food. The results indicate that the metal pollution found in some areas have a negative impact on the assemblages of foraminifera. At present, however, this negative impact is not highly alarming. PMID:26372655

  9. Lower miocene larger foraminifera and petroleum potential of the Tai Formation, Mergui Group, Andaman Sea

    Science.gov (United States)

    Polachan, Songpope; Racey, Andrew

    Tertiary larger foraminifera are recorded for the first time from Thailand. The fauna studied is restricted mainly to the reefal carbonate of the Tai Formation, which rests unconformably on the pre-Late Eocene quartz-chlorite schist basement in the Central High region of the Mergui Basin. The formation is broadly correlatable with the Peutu Formation of the North Sumatra Basin. The Tai Formation can be divided into three units at the type locality; a basal unit of interbedded anhydrite, dolomite, shale and sandstone; a middle unit of coral/algal reefal limestones, and an upper unit of calcarenites interbedded with silty shales and sandstones. The middle and upper units have yielded a fauna comprising; Lepidocyclina (Nephrolepidina) japonica, Spiroclypeus yabeii, Cycloclypeus eidae, Cycloclypeus sp. A, Heterostegina sp. A, Lepidocyclina (N) sp. A, Miogypsina sp. A, and Miogypsinoides sp. L. (N) japonica and Miogypsinoides sp. can range up into the Middle Miocene (Lower Tf) whilst C. eidae can range down into the Upper Oligocene (Lower Te). The fauna is typical of the Indo-West Pacific Miocene faunal province of Adams (1970) and shows closer affinities to the faunas of Indonesia than those of India-Pakistan.

  10. Tolerance of benthic foraminifera to anthropogenic stressors from three sites of the Egyptian coasts

    Directory of Open Access Journals (Sweden)

    Amani Badawi

    2016-03-01

    Full Text Available Surely the coupling of natural and anthropogenic stressors combined with a lack of regulation resulted in the current threat to a large part of coastal marine biodiversity as well as coastal human societies, particularly in highly populated regions. The distribution pattern of benthic foraminifera as sensitive bio-indicator is utilized to assess human-induced impact on the coastal area, at Alexandria, Port Said and Suez cites of Egypt. Twenty-two benthic foraminiferal genera were identified and complied by principal component analysis into four factors through cluster analysis. Cross correlation of the generic composition, distribution and relative abundance of common genera in the three investigated cores revealed three different coastal environments entities. The categorized environment ranged from light human impact as Alexandria site to heavily impacted by human activities as Port Said and Suez sites. Fauna of Alexandria site reflects an increase in un-polluted water activity revealing high-energy erosive environment. The second entity involves Port Said site, which represents a highly stressed coastal environment, corresponding to high-energy transport conditions influenced by fresh water flush from local Manzala Lake via Bougaz El Gamel outlet while Suez site is influenced by marine hypersaline water coupling with intensified levels of industrial and domestic pollution, attributed to the anthropogenic impact.

  11. Automated cleaning of foraminifera shells before Mg/Ca analysis using a pipette robot

    Science.gov (United States)

    Johnstone, Heather J. H.; Steinke, Stephan; Kuhnert, Henning; Bickert, Torsten; Pälike, Heiko; Mohtadi, Mahyar

    2016-08-01

    The molar ratio of magnesium to calcium (Mg/Ca) in foraminiferal calcite is a widely used proxy for reconstructing past seawater temperatures. Thorough cleaning of tests is required before analysis to remove contaminant phases such as clay and organic matter. We have adapted a commercial pipette robot to automate an established cleaning procedure, the "Mg-cleaning" protocol of Barker et al. (2003). Efficiency of the automated nine-step method was assessed through monitoring Al/Ca of trial samples (GeoB4420-2 core catcher). Planktonic foraminifera Globigerinoides ruber, Globigerinoides sacculifer, and Neogloboquadrina dutertrei from this sample gave Mg/Ca consistent with the habitat range of the three species, and 40-60% sample recovery after cleaning. Comparison between manually cleaned and robot-cleaned samples of G. ruber (white) from a sediment core (GeoB16602) showed good correspondence between the two methods for Mg/Ca (r = 0.93, p robot-cleaned samples was 0.05 mmol/mol, showing that the samples are cleaned effectively by the robot. The robot offers increased sample throughput as batch sizes of up to 88 samples/blanks can be processed in ˜7 h with little intervention.

  12. Technical Note: On methodologies for determining the size-normalised weight of planktic foraminifera

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    C. J. Beer

    2010-07-01

    Full Text Available The size-normalised weight (SNW of planktic foraminifera, a measure of test wall thickness and density, is potentially a valuable palaeo-proxy for marine carbon chemistry. As increasing attention is given to developing this proxy it is important that methods are comparable between studies. Here, we compare SNW data generated using two different methods to account for variability in test size, namely (i the narrow (50 μm range sieve fraction method and (ii the individually measured test size method. Using specimens from the 200–250 μm sieve fraction range collected in multinet samples from the North Atlantic, we find that sieving does not constrain size sufficiently well to isolate changes in weight driven by variations in test wall thickness and density from those driven by size. We estimate that the SNW data produced as part of this study are associated with an uncertainty, or error bar, of about ±11%. Errors associated with the narrow sieve fraction method may be reduced by decreasing the size of the sieve window, by using larger tests and by increasing the number tests employed. In situations where numerous large tests are unavailable, however, substantial errors associated with this sieve method remain unavoidable. In such circumstances the individually measured test size method provides a better means for estimating SNW because, as our results show, this method isolates changes in weight driven by variations in test wall thickness and density from those driven by size.

  13. Mg/Ca and δ18O in the calcite of benthic foraminifera: does size matter?

    Science.gov (United States)

    de Nooijer, Lennart; Bijma, Jelle; -Jan Reichart, Gert; Hathorne, Ed

    2010-05-01

    Mg/Ca and del-18O are popular proxies for past sea water temperatures, ice volume and, together, salinity. The biological control that foraminifera have over calcification results in precipitation of calcium carbonate that has an isotope and element composition that is very different from those of inorganically precipitated calcium carbonates. Indications for an effect of ontogeny (i.e. size of a specimen) on the fractionation of oxygen isotopes are contradictory, while for the incorporation of most (trace) elements, data are lacking. The causes of size-based variability in element incorporation and isotope fractionation need to be understood and quantified in order to reliably use them as paleoproxies. In this study, we present Mg/Ca and oxygen isotope data from cultured specimens of the benthic foraminifer Ammonia tepida. When asexual reproduction takes place in this species, 50-300 genetically identical juveniles (i.e. clones) are produced. These juveniles are cultured at constant temperature, carbonate chemistry, salinity, etc to determine inter- and intra-specimen variability in Mg/Ca, Ba/Ca and Sr/Ca. From the same groups of clones, del-18O was determined from specimens with different sizes. Results show that the variability differs greatly between the analysed elements (e.g. relatively constant for Sr and Ba, variable for Mg) and isotopes, underscoring the need for a biological understanding of foraminiferal calcification pathways.

  14. Benthic foraminifera (Protista) as tools in deep-water palaeoceanography: environmental influences on faunal characteristics.

    Science.gov (United States)

    Gooday, Andrew J

    2003-01-01

    Foraminiferal research lies at the border between geology and biology. Benthic foraminifera are a major component of marine communities, highly sensitive to environmental influences, and the most abundant benthic organisms preserved in the deep-sea fossil record. These characteristics make them important tools for reconstructing ancient oceans. Much of the recent work concerns the search for palaeoceanographic proxies, particularly for the key parameters of surface primary productivity and bottom-water oxygenation. At small spatial scales, organic flux and pore-water oxygen profiles are believed to control the depths at which species live within the sediment (their 'microhabitats'). Epifaunal/shallow infaunal species require oxygen and labile food and prefer relatively oligotrophic settings. Some deep infaunal species can tolerate anoxia and are closely linked to redox fronts within the sediment; they consume more refractory organic matter, and flourish in relatively eutrophic environments. Food and oxygen availability are also key factors at large (i.e. regional) spatial scales. Organic flux to the sea floor, and its seasonality, strongly influences faunal densities, species compositions and diversity parameters. Species tend to be associated with higher or lower flux rates and the annual flux range of 2-3 g Corg m-2 appears to mark an important faunal boundary. The oxygen requirements of benthic foraminifera are not well understood. It has been proposed that species distributions reflect oxygen concentrations up to fairly high values (3 ml l-1 or more). Other evidence suggests that oxygen only begins to affect community parameters at concentrations < 0.5 ml l-1. Different species clearly have different thresholds, however, creating species successions along oxygen gradients. Other factors such as sediment type, hydrostatic pressure and attributes of bottom-water masses (particularly carbonate undersaturation and current flow) influence foraminiferal distributions

  15. The 'Natural Laboratory', a tool for deciphering growth, lifetime and population dynamics in larger benthic foraminifera

    Science.gov (United States)

    Hohenegger, Johann

    2015-04-01

    The shells of symbiont-bearing larger benthic Foraminifera (LBF) represent the response to physiological requirements in dependence of environmental conditions. All compartments of the shell such as chambers and chamberlets accommodate the growth of the cell protoplasm and are adaptations for housing photosymbiotic algae. Investigations on the biology of LBF were predominantly based on laboratory studies. The lifetime of LBF under natural conditions is still unclear. LBF, which can build >100 chambers during their lifetime, are thought to live at least one year under natural conditions. This is supported by studies on population dynamics of eulittoral foraminifera. In species characterized by a time-restricted single reproduction period the mean size of specimens increases from small to large during lifetime simultaneously reducing individual number. This becomes more complex when two or more reproduction times are present within a one-year cycle leading to a mixture of abundant small individuals with few large specimens during the year, while keeping mean size more or less constant. This mixture is typical for most sublittoral megalospheric (gamonts or schizonts) LBF. Nothing is known on the lifetime of agamonts, the diploid asexually reproducing generation. In all hyaline LBF it is thought to be significantly longer than 1 year based on the large size and considering the mean chamber building rate of the gamont/schizonts. Observations on LBF under natural conditions have not been performed yet in the deeper sublittoral. This reflects the difficulties due to intense hydrodynamics that hinder deploying technical equipment for studies in the natural environment. Therefore, studying growth, lifetime and reproduction of sublittoral LBF under natural conditions can be performed using the so-called 'natural laboratory' in comparison with laboratory investigations. The best sampling method in the upper sublittoral from 5 to 70 m depth is by SCUBA diving. Irregular

  16. Molecular evidence for Lessepsian invasion of soritids (larger symbiont bearing benthic foraminifera.

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    Gily Merkado

    Full Text Available The Mediterranean Sea is considered as one of the hotspots of marine bioinvasions, largely due to the influx of tropical species migrating through the Suez Canal, so-called Lessepsian migrants. Several cases of Lessepsian migration have been documented recently, however, little is known about the ecological characteristics of the migrating species and their aptitude to colonize the new areas. This study focused on Red Sea soritids, larger symbiont-bearing benthic foraminifera (LBF that are indicative of tropical and subtropical environments and were recently found in the Israeli coast of the Eastern Mediterranean. We combined molecular phylogenetic analyses of soritids and their algal symbionts as well as network analysis of Sorites orbiculus Forskål to compare populations from the Gulf of Elat (northern Red Sea and from a known hotspot in Shikmona (northern Israel that consists of a single population of S. orbiculus. Our phylogenetic analyses show that all specimens found in Shikmona are genetically identical to a population of S. orbiculus living on a similar shallow water pebbles habitat in the Gulf of Elat. Our analyses also show that the symbionts found in Shikmona and Elat soritids belong to the Symbiodinium clade F5, which is common in the Red Sea and also present in the Indian Ocean and Caribbean Sea. Our study therefore provides the first genetic and ecological evidences that indicate that modern population of soritids found on the Mediterranean coast of Israel is probably Lessepsian, and is less likely the descendant of a native ancient Mediterranean species.

  17. 13C-18O isotope signatures and ‘clumped isotope’ thermometry in foraminifera and coccoliths

    Science.gov (United States)

    Tripati, Aradhna K.; Eagle, Robert A.; Thiagarajan, Nivedita; Gagnon, Alexander C.; Bauch, Henning; Halloran, Paul R.; Eiler, John M.

    2010-10-01

    Accurate constraints on past ocean temperatures and compositions are critical for documenting climate change and resolving its causes. Most proxies for temperature are not thermodynamically based, appear to be subject to biological processes, require regional calibrations, and/or are influenced by fluid composition. As a result, their interpretation becomes uncertain when they are applied in settings not necessarily resembling those in which they were empirically calibrated. Independent proxies for past temperature could provide an important means of testing and/or expanding on existing reconstructions. Here we report measurements of abundances of stable isotopologues of calcitic and aragonitic benthic and planktic foraminifera and coccoliths, relate those abundances to independently estimated growth temperatures, and discuss the possible scope of equilibrium and kinetic isotope effects. The proportions of 13C- 18O bonds in these samples exhibits a temperature dependence that is generally similar to that previously been reported for inorganic calcite and other biologically precipitated carbonate-containing minerals (apatite from fish, reptile, and mammal teeth; calcitic brachiopods and molluscs; aragonitic coral and mollusks). Most species that exhibit non-equilibrium 18O/ 16O (δ 18O) and 13C/ 12C (δ 13C) ratios are characterized by 13C- 18O bond abundances that are similar to inorganic calcite and are generally indistinguishable from apparent equilibrium, with possible exceptions among benthic foraminiferal samples from the Arctic Ocean where temperatures are near-freezing. Observed isotope ratios in biogenic carbonates can be explained if carbonate minerals generally preserve a state of ordering that reflects the extent of isotopic equilibration of the dissolved inorganic carbon species.

  18. Controls on magnesium and strontium uptake in planktonic foraminifera determined by live culturing

    Energy Technology Data Exchange (ETDEWEB)

    Lea, D.W.; Mashiotta, T.A. [Univ. of California, Santa Barbara, CA (United States); Spero, H.J. [Univ. of California, Davis, CA (United States). Dept. of Geology

    1999-08-01

    Because strontium and magnesium occur in seawater with nearly constant ratios to calcium, variations in Sr/Ca and Mg/Ca in modern foraminifer shells are due to the influence of environmental parameters on calcification. The authors have cultured two species of planktonic foraminifera, Globigerina bulloides and Orbulina universa, to establish the influence of temperature, pH, and salinity. Experimental results indicate that temperature is the primary control on shell Mg/Ca and that shell Mg/Ca increases exponentially by about 8 to 10% per {degree}C. The exponential rise in shell Mg with temperature mirrors the results from inorganic precipitation experiments and suggests at least partial thermodynamic control on Mg incorporation. Both seawater pH and salinity are secondary influences on shell Mg/Ca: {minus}6% per 0.1 pH unit increase and +4% per salinity unit increase. Shell Sr/Ca responds far more weakly to environmental parameters, and the small range observed in shell Sr/Ca relative to measurement precision of the ICP-MS method used here limits how well controls on shell Sr can be determined. Higher temperature, salinity, and pH all appear to increase shell Sr/Ca, most likely through the kinetic influence of calcification. Culturing results demonstrate the potential of Mg/Ca in G. bulloides as a paleothermometer. The culturing results suggest that the standard error of Mg paleothermometry is {+-}1.1 C, but when the secondary effects of salinity and pH are considered the error increases to {+-}1.3 C.

  19. Benthic foraminifera records in marine sediments during the Holocene from Pescadero basin, Gulf of California, Mexico

    Science.gov (United States)

    Valdez, M.; Perez-Cruz, L. L.; Roy, P.; Monreal, M.; Fenero, R.

    2013-05-01

    Gravity core T-56 (256 cm length) was collected in Pescadero Basin located on the western side of the Gulf of California within the oxygen minim zone (OMZ) at 597 cm depth, aboard of the R/V "El Puma". Pescadero basin is located at mouth of the gulf; because of its location is sensitive to record the changes in the gulf and in the Eastern Pacific Ocean. The sedimentary sequence is analyzed to contribute to the understanding the oceanographic variability in the southern part of the gulf of California during the Holocene using benthic foraminifera assemblages and organic carbon as proxies of organic matter flux and bottom water oxygenation. In general, the core is characterized by silty-clay sediments, and it exhibits a turbidite between 198 and 134 cm, distinguished by sandy sediments and reworking material. From 134 cm to the top shows a visible laminated structure. The initial chronology is based on three AMS radiocarbon dates, and estimated sedimentation rates are 0.22 and 0.19 mm/yr for the first 32 cm of the core. Six radiocarbon dates are in progress. Preliminary results of benthic foraminiferal assemblages showed that species of Bolivina are dominated, mainly megalospheric forms, from 134 cm to top of the core. They are small and thin-shelled forms (e.g., Bolivina subadvena, Bolivina minuta, Bolivina seminuda, Bolivina plicata), and also Buliminella, Cassidulina and Epistominella are abundant. In particular, species of Bolivina are environmental indicators and exhibit a typical reproductive dimorphism. The predominance of the genus Bolivina suggest organic flux variations, because of the productivity changes that might be related to changes in ocean circulation and in the environmental variability in the region.

  20. Foraminifera as bioindicators in coral reef assessment and monitoring: The foram index

    Science.gov (United States)

    Hallock, P.; Lidz, B.H.; Cockey-Burkhard, E. M.; Donnelly, K.B.

    2003-01-01

    Coral reef communities are threatened worldwide. Resource managers urgently need indicators of the biological condition of reef environments that can relate data acquired through remote-sensing, water-quality and benthic-community monitoring to stress responses in reef organisms. The "FORAM" (Foraminifera in Reef Assessment and Monitoring) Index (FI) is based on 30 years of research on reef sediments and reef-dwelling larger foraminifers. These shelled protists are ideal indicator organisms because: ??? Foraminifers are widely used as environmental and paleoenvironmental indicators in many contexts; ??? Reef-building, zooxanthellate corals and foraminifers with algal symbionts have similar water-quality requirements; ??? The relatively short life spans of foraminifers as compared with long-lived colonial corals facilitate differentiation between long-term water-quality decline and episodic stress events; ??? Foraminifers are relatively small and abundant, permitting statistically significant sample sizes to be collected quickly and relatively inexpensively, ideally as a component of comprehensive monitoring programs; and ??? Collection of foraminifers has minimal impact on reef resources. USEPA guidelines for ecological indicators are used to evaluate the FI. Data required are foraminiferal assemblages from surface sediments of reef-associated environments. The FI provides resource managers with a simple procedure for determining the suitability of benthic environments for communities dominated by algal symbiotic organisms. The FI can be applied independently, or incorporated into existing or planned monitoring efforts. The simple calculations require limited computer capabilities and therefore can be applied readily to reef-associated environments worldwide. In addition, the foraminiferal shells collected can be subjected to morphometric and geochemical analyses in areas of suspected heavy-metal pollution, and the data sets for the index can be used with other

  1. Biodiversity and community structure of deep-sea foraminifera around New Zealand

    Science.gov (United States)

    Buzas, Martin A.; Hayek, Lee-Ann C.; Hayward, B. W.; Grenfell, Hugh R.; Sabaa, Ashwaq T.

    2007-09-01

    The biodiversity and community structure of benthic foraminifera were estimated from 217 stations distributed in four geographic regions (north, south, east, west) around New Zealand. An analytical method accumulating sample values of species richness (S), the information function (H) and evenness (E) with increasing number of individuals (N) called SHE analysis was used to establish 16 foraminiferal communities and their community structure at shelf (0-200 m), bathyal (200-2000 m) and abyssal (>2000m) depths. A decrease in S, H and E occurs from north to south and this latitudinal gradient extends to abyssal depths. An increase in S and H with depth occurs in the northern and southern areas. For lnS, H and lnE against lnN, regression lines on values obtained from SHE analysis at shelf, bathyal and abyssal depths all diverge in the southern area. Each of the other areas exhibits crossing of regression lines so that establishing the rank order of S, H or E with depth within an area requires consideration of N. For a log series pattern, H is a constant proportional to α, the parameter of the log series, and, based on the decomposition equation lnS=H+lnE, a regression of lnS against lnE yields a regression coefficient of -1 and an intercept of H. At depths of less than 1000 m, 2 of 8 communities have regression coefficient confidence intervals that include -1. At depths of greater than 1000 m, 7 of 8 communities intervals include -1. Thus, overall, the majority of cases, but especially those at depths greater than 1000 m, have a log series pattern.

  2. The seasonal succession of modern planktonic foraminifera: Sediment traps observations from southwest Taiwan waters

    Science.gov (United States)

    Lin, Hui-Ling

    2014-08-01

    The seasonal succession and stable isotope compositions of living planktonic foraminifera collected in sediment traps from the continental shelf/slope off southwest Taiwan were investigated. Sediment trap moorings were deployed at water depths of ~816 m and ~233/250 m during October-November 2009, March-April 2010 and July-August 2010. The sampling duration was 3 days for each collecting cup, yielding 36 days/12 cups per individual mooring over the three sampling periods. All planktonic foraminiferal tests greater than 150 μm were picked, identified and counted for the faunal census. The variations in shell abundance (#/g; number of specimens per gram of original bulk sample) and size frequency show a pattern which seems to be related to the lunar cycle: shell abundances increase from low concentration at the new moon and reach their maxima before the full moon. Occurrences of larger foraminiferal shells also gradually increase as the collection approaching to full moon. The faunal assemblages were dominated by Globigerinella aequilateralis, Globigerinoides sacculifer, Globorotalia menardii, Globigerinoides ruber, Neogloboquadrina dutertrei, and Pulleniatina obliquiloculata; these six species constituting 30-80% of all foraminiferal tests found in the sediment traps. The seasonal contrast within the faunal assemblage between these three deployment periods, however, is not very evident except for the relative abundance of G. sacculifer and G. ruber. G. ruber is more abundant in summer than in spring whereas G. sacculifer shows an inverse pattern. Seasonal differences in the δ18O of P. obliquiloculata, G. sacculifer and G. ruber can be well explained by temperature profiles in the water column, while variations of δ13C are not related to the chlorophyll concentration hence to productivity. In addition, the calcifying depths reflected by three species are estimated to be ~40 m for G. ruber; ~60 m for G. sacculifer; and >80 m for P. obliquiloculata.

  3. Annual and seasonal distribution of intertidal foraminifera and stable carbon isotope geochemistry, Bandon Marsh, Oregon, USA

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin; Vane, Christopher; Engelhart, Simon; Nelson, Alan R.; Witter, Robert C.; Khan, Nicole S.; Bridgeland, William

    2014-01-01

    We investigated the influence of inter-annual and seasonal differences on the distribution of live and dead foraminifera, and the inter-annual variability of stable carbon isotopes (d13C), total organic carbon (TOC) values and carbon to nitrogen (C/N) ratios in bulk sediments from intertidal environments of Bandon Marsh (Oregon, USA). Living and dead foraminiferal species from 10 stations were analyzed over two successive years in the summer (dry) and fall (wet) seasons. There were insignificant inter-annual and seasonal variations in the distribution of live and dead species. But there was a noticeable decrease in calcareous assemblages (Haynesina sp.) between live populations and dead assemblages, indicating that most of the calcareous tests were dissolved after burial; the agglutinated assemblages were comparable between constituents. The live populations and dead assemblages were dominated by Miliammina fusca in the tidal flat and low marsh, Jadammina macrescens, Trochammina inflata and M. fusca in the high marsh, and Trochamminita irregularis and Balticammina pseudomacrescens in the highest marsh to upland. Geochemical analyses (d13C, TOC and C/N of bulk sedimentary organic matter) show no significant influence of inter-annual variations but a significant correlation of d13C values (R = 20.820, p , 0.001), TOC values (R = 0.849, p , 0.001) and C/N ratios (R = 0.885, p , 0.001) to elevation with respect to the tidal frame. Our results suggest that foraminiferal assemblages and d13C and TOC values, as well as C/N ratios, in Bandon Marsh are useful in reconstructing paleosea-levels on the North American Pacific coast.

  4. Benthic Foraminifera, Food in the Deep Sea, and Limits to Bentho-Pelagic Coupling

    Science.gov (United States)

    Thomas, E.; Boscolo-Galazzo, F.; Arreguin-Rodrigu, G. J.; Ortiz, S.; Alegret, L.

    2015-12-01

    The deep-sea is the largest habitat on Earth, contains highly diverse biota, but is very little known. Many of its abundant benthic biota (e.g., nematodes) are not preserved in the fossil record. Calcareous and agglutinated benthic foraminifera (unicellular eukaryotes, Rhizaria; efficient dispersers) and ostracodes (Animalia, Crustacea; non-efficient dispersers) are the most common organisms providing a fossil record of deep-sea environments. Very little food is supplied to the deep-sea, because organic matter produced by photosynthesis is largely degraded before it arrives at the seafloor. Only a few % of organic matter is carried to the ocean bottom by 'marine snow', with its particle size and behavior in the water column controlled by surface ecosystem structure, including type of dominant primary producers (diatoms, cyanobacteria). Food supply and its seasonality are generally seen as the dominant control on benthic assemblages (combined with oxygenation), providing bentho-pelagic coupling between primary and benthic productivity. Benthic foraminiferal assemblages (composition and density) thus are used widely to estimate past productivity, especially during episodes of global climate change, ocean acidification, and mass extinction of primary producers. We show that some environmental circumstances may result in interrupting bentho-pelagic coupling, e.g. through lateral supply of organic matter along continental margins (adding more refractory organic matter), through trophic focusing and/or fine particle winnowing on seamounts (giving an advantage to suspension feeders), and through carbonate undersaturation (giving advantage to infaunal over epifaunal calcifyers). In addition, increased remineralization of organic matter combined with increased metabolic rates may cause assemblages to reflect more oligotrophic conditions at stable primary productivity during periods of global warming. As a result, benthic foraminiferal accumulation rates must be carefully

  5. Paleoecology of Benthic Foraminifera in Coral Reefs Recorded in the Jurassic Tuwaiq Mountain Formation of the Khashm Al-Qaddiyah Area, Central Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Mohamed Youssef; Abdelbaset S El-Sorogy

    2015-01-01

    Thirty three benthic foraminiferal species belong to 23 genera and 16 families have been recorded from the coral reefs of the Callovian Tuwaiq Formation, Khashm Al-Qaddiyah area, Central Saudi Arabia. Three species:Astacolus qaddiyahensis, Nodosaria riyadhensis, Siderolites jurassica are believed to be new. Nearly all identified foraminifera are of Atlantic-Miditeranean affinity. The fo-raminiferal assemblage recorded in the present work is mixed of open marine, moderately deep ma-rine conditions associations and shallow to deep lagoon. The reefal part of upper Twiaq Formation may have been deposited in shallow water of lower to middle shelf depth (20–50 m) as indicated by abundant corals and benthic foraminifera. The coral fauna and bearing benthic foraminifera indi-cated moderate water energy.

  6. Bioerosion by microbial euendoliths in benthic foraminifera from heavy metal-polluted coastal environments of Portovesme (South-Western Sardinia, Italy

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    A. Cherchi

    2012-08-01

    Full Text Available A monitoring survey of the coastal area facing the industrial area of Portoscuso-Portovesme (South-Western Sardinia, Italy revealed intense bioerosional processes. Benthic foraminifera collected at the same depth (about 2 m but at different distances from the pollution source show extensive microbial infestation, anomalous Mg/Ca molar ratios and high levels of heavy metals in the shell associated with a decrease in foraminifera richness, population density and biodiversity with the presence of morphologically abnormal specimens. We found that carbonate dissolution induced by euendoliths is selective, depending on the Mg content and morpho-structural types of foraminiferal taxa. This study provides evidences for a connection between heavy metal dispersion, decrease in pH of the sea-water and bioerosional processes on foraminifera.

  7. Quantitative vertical zonation of salt-marsh foraminifera for reconstructing former sea level; an example from New Jersey, USA.

    Science.gov (United States)

    Kemp, Andrew C.; Horton, Benjamin P.; Vann, David R.; Engelhart, Simon E.; Grand Pre, Candace A.; Vane, Christopher H.; Nikitina, Daria; Anisfeld, Shimon C.

    2012-10-01

    We present a quantitative technique to reconstruct sea level from assemblages of salt-marsh foraminifera using partitioning around medoids (PAM) and linear discriminant functions (LDF). The modern distribution of foraminifera was described from 62 surface samples at three salt marshes in southern New Jersey. PAM objectively estimated the number and composition of assemblages present at each site and showed that foraminifera adhered to the concept of elevation-dependent ecological zones, making them appropriate sea-level indicators. Application of PAM to a combined dataset identified five distinctive biozones occupying defined elevation ranges, which were similar to those identified elsewhere on the U.S. mid-Atlantic coast. Biozone A had high abundances of Jadammina macrescens and Trochammina inflata; biozone B was dominated by Miliammina fusca; biozone C was associated with Arenoparrella mexicana; biozone D was dominated by Tiphotrocha comprimata and biozone E was dominated by Haplophragmoides manilaensis. Foraminiferal assemblages from transitional and high salt-marsh environments occupied the narrowest elevational range and are the most precise sea-level indicators. Recognition of biozones in sequences of salt-marsh sediment using LDFs provides a probabilistic means to reconstruct sea level. We collected a core to investigate the practical application of this approach. LDFs indicated the faunal origin of 38 core samples and in cross-validation tests were accurate in 54 of 56 cases. We compared reconstructions from LDFs and a transfer function. The transfer function provides smaller error terms and can reconstruct smaller RSL changes, but LDFs are well suited to RSL reconstructions focused on larger changes and using varied assemblages. Agreement between these techniques suggests that the approach we describe can be used as an independent means to reconstruct sea level or, importantly, to check the ecological plausibility of results from other techniques.

  8. Benthic foraminifera distribution in high polluted sediments from Niterói Harbor (Guanabara Bay, Rio de Janeiro, Brazil

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    Claudia G. Vilela

    2004-03-01

    Full Text Available Dockyards and harbors are recognized as being important locations where sediment-associated pollutants can accumulate, which constitutes an environmental risk to aquatic life due to potential uptake and accumulation of heavy metals in the biota. The aim of this paper is to assess the concentrations and the effects of some heavy metals in the benthic foraminifera assemblage in Niterói Harbor. Low concentrations in the benthic foraminifera as well as the dominance of indicative species such as Ammonia tepida, Buliminella elegantissima and Bolivina lowmani can be associated with an environment under stress. In addition, the occurrence of test abnormalities among foraminifera may represent a useful biomarker for evaluating long-term environmental impacts in a coastal region.Estaleiros e portos são locais reconhecidamente importantes onde poluentes associados a sedimentos podem acumular, constituindo um risco ambiental para a vida aquática devido ao potencial de captação e acumulação de metais pesados na biota. O propósito deste trabalho é avaliar as concentrações e os efeitos de alguns metais pesados na assembléia de foraminíferos bentônicos no Porto de Niterói. Baixas concentrações de foraminíferos bentônicos bem como a dominância de espécies indicativas como Ammonia tepida, Buliminella elegantissima e Bolivina lowmani podem ser associadas a um ambiente sob estresse. A ocorrência de anormalidades entre os foraminíferos pode representar um útil biomarcador para avaliação de impactos ambientais de longo termo em uma região costeira.

  9. Methodology for single-cell genetic analysis of planktonic foraminifera for studies of protist diversity and evolution

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    Agnes Katharina Maria Weiner

    2016-12-01

    Full Text Available Single-cell genetic analysis is an essential method to investigate the biodiversity and evolutionary ecology of marine protists. In protist groups that do not reproduce under laboratory conditions, this approach provides the only means to directly associate molecular sequences with cell morphology. The resulting unambiguous taxonomic identification of the DNA sequences is a prerequisite for barcoding and analyses of environmental metagenomic data. Extensive single-cell genetic studies have been carried out on planktonic foraminifera over the past 20 years to elucidate their phylogeny, cryptic diversity, biogeography and the relationship between genetic and morphological variability. In the course of these investigations, it has become evident that genetic analysis at the individual specimen level is confronted by innumerable challenges ranging from the negligible amount of DNA present in the single cell to the substantial amount of DNA contamination introduced by endosymbionts or food particles. Consequently, a range of methods has been developed and applied throughout the years for the genetic analysis of planktonic foraminifera in order to enhance DNA amplification success rates. Yet, the description of these methods in the literature rarely occurred with equivalent levels of detail and the different approaches have never been compared in terms of their efficiency and reproducibility. Here, aiming at a standardization of methods, we provide a comprehensive review of all methods that have been employed for the single-cell genetic analysis of planktonic foraminifera. We compile data on success rates of DNA amplification and use these to evaluate the effects of key parameters associated with the methods of sample collection, storage and extraction of single-cell DNA. We show that the chosen methods influence the success rates of single-cell genetic studies, but the differences between them are not sufficient to hinder comparisons between studies

  10. Investigation of the calcification response of foraminifera and pteropods to high CO2 environments in the Pleistocene, Paleogene and Cretaceous

    Science.gov (United States)

    Hart, M.; Pettit, L.; Wall-Palmer, D.; Smart, C.; Hall-Spencer, J.; Medina-Sanchez, A.; Prol Ledesma, R. M.; Rodolfo-Metalpa, R.; Collins, P.

    2012-04-01

    Ocean acidification is regarded as a current problem and there is an extensive literature on how various organisms are responding to changes in oceanic pH: the result of increasing atmospheric pCO2. Acidification is, however, not just a recent phenomenon and there are times in the geological record where pCO2 has been higher than present day levels (especially in the Cretaceous and Paleogene). Understanding the response of various microfossil groups to the changes in oceanic pH is on-going as part of a major investigation of ocean acidification in both modern and 'fossil' environments. Extensive carbon dioxide vents have recently been described in the Wagner Basin (northern Gulf of California, Mexico), which cause dramatic changes in carbonate chemistry. The pHT decreased from 7.88 to 7.55 near the most active vents where the lowest saturation states of aragonite (ΩArag) and calcite (ΩCalc) were 0.95 and 1.47 respectively. Foraminifera (unicellular protists) present in the top 2 cm of the sediment (both living and dead individuals) had a range of mainly calcareous taxa (including Bolivina acuminata, B. acutula, Bulimina marginata and Nonionella basispinata). This is a normal composition for these water depths. The lack of dissolution features and the generally good preservation of the tests, even when viewed under a scanning electron microscope, were striking. With no evidence of breakage caused by transportation, it is assumed that this composition is representative in terms of numbers of individuals and taxa represented. Benthic foraminifera from CO2 vents around the island of Ischia (Italy) have shown dramatic long-term effects of ocean acidification. The foraminifera of the Wagner Basin appear to be surviving in high CO2 environments comparable to those that occurred during the Cretaceous-Paleogene "greenhouse" world where atmospheric pCO2 was much higher, but with calcareous foraminifera apparently thriving. In the Pleistocene, pCO2 levels are known to have

  11. A New Integrated Approach to Taxonomy: The Fusion of Molecular and Morphological Systematics with Type Material in Benthic Foraminifera

    Science.gov (United States)

    Roberts, Angela; Austin, William; Evans, Katharine; Bird, Clare; Schweizer, Magali; Darling, Kate

    2016-01-01

    A robust and consistent taxonomy underpins the use of fossil material in palaeoenvironmental research and long-term assessment of biodiversity. This study presents a new integrated taxonomic protocol for benthic foraminifera by unequivocally reconciling the traditional taxonomic name to a specific genetic type. To implement this protocol, a fragment of the small subunit ribosomal RNA (SSU rRNA) gene is used in combination with 16 quantitative morphometric variables to fully characterise the benthic foraminiferal species concept of Elphidium williamsoni Haynes, 1973. A combination of live contemporary topotypic specimens, original type specimens and specimens of genetic outliers were utilised in this study. Through a series of multivariate statistical tests we illustrate that genetically characterised topotype specimens are morphologically congruent with both the holotype and paratype specimens of E. williamsoni Haynes, 1973. We present the first clear link between morphologically characterised type material and the unique SSU rRNA genetic type of E. williamsoni. This example provides a standard framework for the benthic foraminifera which bridges the current discontinuity between molecular and morphological lines of evidence, allowing integration with the traditional Linnaean roots of nomenclature to offer a new prospect for taxonomic stability. PMID:27388271

  12. Five new species and one new genus of recent miliolid foraminifera from Raja Ampat (West Papua, Indonesia

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    Meena Förderer

    2016-06-01

    Full Text Available Raja Ampat is an archipelago of about 1,500 small islands located northwest off the Bird’s Head Peninsula of Indonesia’s West Papua province. It is part of the Coral Triangle, a region recognized as the “epicenter” of tropical marine biodiversity. In the course of a large-scale survey on shallow benthic foraminifera we have discovered one new genus and five new species of recent miliolid benthic foraminifera from the highly diverse reefal and nearshore environments. The new fischerinid genus Dentoplanispirinella is characterized by its planispiral coiling and by the presence of a simple tooth, that differentiate it from Planispirinella Wiesner. It is represented in our sample material by the new species Dentoplanispirinella occulta. The other four species described herein are Miliolinella moia, Miliolinella undina, Triloculina kawea and Siphonaperta hallocki. All new species are comparatively rare and occur sporadically in the sample material. Detailed morphological descriptions, scanning electron microscopy pictures of complete and dissected specimens as well as micro-computed tomography images are provided.

  13. Evaluation of the ecological effects of heavy metals on the assemblages of benthic foraminifera of the canals of Aveiro (Portugal)

    Science.gov (United States)

    Martins, V.; da Silva, E. Ferreira; Sequeira, C.; Rocha, F.; Duarte, A. C.

    2010-04-01

    Aveiro is a town with 80,000 inhabitants situated in the central west coast of Portugal. It is located at the centre of the Ria de Aveiro, a coastal lagoon that functions as a multi-estuarine area. This town is crossed by several canals which are connected with lagoon channels through canal locks. The operation of the canal locks influences the hydro dynamism in Aveiro's canal and this and other human activities have left a sedimentary record. The study of these records was based on the sediments grain size and composition, mineralogy (by XRD techniques), geochemical (by ICP-MS), total organic carbon (TOC), and microfaunal (benthic foraminifera) content in 15 grab-samples collected in 2006 in Aveiro's canal. The total elemental concentrations evaluated by total digestion of the sediment fraction canals, related to legacies of past industrial activities. These "hot spots" have, for instance, higher available concentrations of Al, Cd, Co, Cu, Fe, Pb, Mn and Zn (evaluated by sequential chemical extractions) and are located in Paraíso, Alboi, Botirões and Cojo Canals, at sites where the sediments are finer and richer in TOC. Abiotic and biotic variables submitted to principal component analysis and cluster analysis highlights the hydrodynamics and human effects on the system and the negative influence of pollutants on the benthic organisms (foraminifera).

  14. Link between light-triggered Mg-banding and chamber formation in the planktic foraminifera Neogloboquadrina dutertrei

    Science.gov (United States)

    Fehrenbacher, Jennifer S.; Russell, Ann D.; Davis, Catherine V.; Gagnon, Alexander C.; Spero, Howard J.; Cliff, John B.; Zhu, Zihua; Martin, Pamela

    2017-05-01

    The relationship between seawater temperature and the average Mg/Ca ratios in planktic foraminifera is well established, providing an essential tool for reconstructing past ocean temperatures. However, many species display alternating high and low Mg-bands within their shell walls that cannot be explained by temperature alone. Recent experiments demonstrate that intrashell Mg variability in Orbulina universa, which forms a spherical terminal shell, is paced by the diurnal light/dark cycle. Whether Mg-heterogeneity is also diurnally paced in species with more complex shell morphologies is unknown. Here we show that high Mg/Ca-calcite forms at night in cultured specimens of the multi-chambered species Neogloboquadrina dutertrei. Our results demonstrate that N. dutertrei adds a significant amount of calcite, and nearly all Mg-bands, after the final chamber forms. These results have implications for interpreting patterns of calcification in N. dutertrei and suggest that diurnal Mg-banding is an intrinsic component of biomineralization in planktic foraminifera.

  15. Elimination of taphonomic bias in late Paleocene to early Eocene paleoenvironmental reconstructions by means of experimental dissolution studies on foraminifera

    Science.gov (United States)

    Nguyen, T. M. P.; Petrizzo, M. R.; Speijer, R. P.

    2009-04-01

    Fossil foraminifera provide a prime tool in marine paleoenvironmental reconstructions. Their shells record physico-chemical conditions in the water column and on the sea floor, which through geochemical analyses are being employed in paleoclimatic, paleoceanographic and stratigraphic researches. Furthermore, the quantitative and taxonomic compositions of foraminiferal assemblages provide insight into numerous aspects of depositional conditions, such as productivity, temperature, etc. Selective dissolution can severely alter the composition of the fossil foraminiferal assemblages. Although preferential dissolution in foraminiferal assemblages is widely recognized in modern and Quaternary deep-sea sediments, the phenomenon is often neglected in studies dealing with Paleogene sediments. Uncritical use of foraminiferal assemblages, without a serious assessment of their preservation may lead to distorted paleoenvironmental reconstructions. We carried out dissolution experiments on upper Paleocene to lower Eocene foraminiferal assemblages and selected taxa from the central Pacific (Allison Guyot and Shatsky Rise) and the Tethys (Dababiya, Egypt) in order to reveal the effects of differential dissolution on the composition of foraminiferal assemblages. Dissolution phenomena are a recurrent problem of upper Paleocene to lower Eocene foraminiferal assemblages, especially in connection with the Paleocene-Eocene Thermal Maximum (PETM). In some sequences severe dissolution is easily recognized by the absence of calcareous foraminifera in clay beds. However, less severe dissolution is rarely documented as such, although there are various more subtle indications, such as increased fragmentation and depressed absolute abundance and P/B ratios. Our study aims to investigate the effects of differential dissolution on the quantitative composition of planktonic and benthic foraminiferal assemblages. More specifically, we aim at developing objective criteria for the evaluation of

  16. Quantifying the effect of seasonal and vertical habitat tracking on planktonic foraminifera proxies

    Science.gov (United States)

    Jonkers, Lukas; Kučera, Michal

    2017-06-01

    The composition of planktonic foraminiferal (PF) calcite is routinely used to reconstruct climate variability. However, PF ecology leaves a large imprint on the proxy signal: seasonal and vertical habitats of PF species vary spatially, causing variable offsets from annual mean surface conditions recorded by sedimentary assemblages. PF seasonality changes with temperature in a way that minimises the environmental change that individual species experience and it is not unlikely that changes in depth habitat also result from such habitat tracking. While this behaviour could lead to an underestimation of spatial or temporal trends as well as of variability in proxy records, most palaeoceanographic studies are (implicitly) based on the assumption of a constant habitat. Up to now, the effect of habitat tracking on foraminifera proxy records has not yet been formally quantified on a global scale. Here we attempt to characterise this effect on the amplitude of environmental change recorded in sedimentary PF using core top δ18O data from six species. We find that the offset from mean annual near-surface δ18O values varies with temperature, with PF δ18O indicating warmer than mean conditions in colder waters (on average by -0.1 ‰ (equivalent to 0.4 °C) per °C), thus providing a first-order quantification of the degree of underestimation due to habitat tracking. We use an empirical model to estimate the contribution of seasonality to the observed difference between PF and annual mean δ18O and use the residual Δδ18O to assess trends in calcification depth. Our analysis indicates that given an observation-based model parametrisation calcification depth increases with temperature in all species and sensitivity analysis suggests that a temperature-related seasonal habitat adjustment is essential to explain the observed isotope signal. Habitat tracking can thus lead to a significant reduction in the amplitude of recorded environmental change. However, we show that this

  17. Boron Isotopes in Benthic Foraminifera by MC-ICPMS: Unlocking the Ocean's Carbon Cycle

    Science.gov (United States)

    Rae, J. W.; Foster, G. L.; Schmidt, D. N.; Elliott, T. R.

    2008-12-01

    The cause of glacial-interglacial CO2 cycles has been described as the "holy grail" of climate science. All models currently proposed invoke changes in deep ocean carbon storage, but the mechanisms by which this took place remain unclear. Proxies for two components of the ocean carbonate system would allow us to fully reconstruct ocean carbonate equilibria and trace the spatial and temporal pattern of glacial carbon storage, providing valuable constraints on the causal mechanisms of atmospheric CO2 change. The theory behind the boron isotope pH proxy is well understood, but its reliability has been questioned, primarily due to uncertainty in the fractionation factor between boron species in seawater, and analytical difficulties associated with negative thermal ionisation (NTIMS) measurements. We have developed a new technique for boron isotopic analysis by multicollector inductively coupled plasma mass spectrometry (MC- ICPMS), which overcomes many of the problems associated with NTIMS measurements. Our method is precise (better than 0.25%, or ~0.02 pH units, on full procedural replicates at 95% confidence), rapid (allowing duplicate measurement of 10-20 samples per analytical session), and has small sample size requirements of ~10 ng boron (~0.5 mg foraminiferal tests). As MC-ICPMS analysis requires separation of boron prior to measurement, any bias between samples and standards with different matrices is also removed. Recent experimental work has also improved uncertainty in the isotopic fractionation factor (now measured at 1.0272 ±0.0006 [1]), providing a powerful independent means to test the behaviour of the foram-based δ11B proxy, and its ability to provide absolute pH values. We have measured δ11B in several species of benthic foraminifera from a range of core-top samples. In contrast to previous studies, we find a very close match between foraminiferal δ11B values and the δ11B of seawater B(OH)4- - predicted using the recently determined fractionation

  18. Three dimensional morphological studies of Larger Benthic Foraminifera at the population level using micro computed tomography

    Science.gov (United States)

    Kinoshita, Shunichi; Eder, Wolfgang; Woeger, Julia; Hohenegger, Johann; Briguglio, Antonino; Ferrandez-Canadell, Carles

    2015-04-01

    Symbiont-bearing larger benthic Foraminifera (LBF) are long-living marine (at least 1 year), single-celled organisms with complex calcium carbonate shells. Their morphology has been intensively studied since the middle of the nineteenth century. This led to a broad spectrum of taxonomic results, important from biostratigraphy to ecology in shallow water tropical to warm temperate marine palaeo-environments. However, it was necessary for the traditional investigation methods to cut or destruct specimens for analysing the taxonomically important inner structures. X-ray micro-computed tomography (microCT) is one of the newest techniques used in morphological studies. The greatest advantage is the non-destructive acquisition of inner structures. Furthermore, the running improve of microCT scanners' hard- and software provides high resolution and short time scans well-suited for LBF. Three-dimensional imaging techniques allow to select and extract each chamber and to measure easily its volume, surface and several form parameters used for morphometric analyses. Thus, 3-dimensional visualisation of LBF-tests is a very big step forward from traditional morphology based on 2-dimensional data. The quantification of chamber form is a great opportunity to tackle LBF structures, architectures and the bauplan geometry. The micrometric digital resolution is the only way to solve many controversies in phylogeny and evolutionary trends of LBF. For the present study we used micro-computed tomography to easily investigate the chamber number of every specimen from statistically representative part of populations to estimate population dynamics. Samples of living individuals are collected at monthly intervals from fixed locations. Specific preparation allows to scan up to 35 specimens per scan within 2 hours and to obtain the complete digital dataset for each specimen of the population. MicroCT enables thus a fast and precise count of all chambers built by the foraminifer from its

  19. The evaluation of Computed Tomography hard- and software tools for micropaleontologic studies on foraminifera

    Science.gov (United States)

    van Loo, D.; Speijer, R.; Masschaele, B.; Dierick, M.; Cnudde, V.; Boone, M.; de Witte, Y.; Dewanckele, J.; van Hoorebeke, L.; Jacobs, P.

    2009-04-01

    Foraminifera (Forams) are single-celled amoeba-like organisms in the sea, which build a tiny calcareous multi-chambered shell for protection. Their enormous abundance, great variation of shape through time and their presence in all marine deposits made these tiny microfossils the oil companies' best friend by facilitating the detection of new oil wells. Besides the success of forams in the oil and gas industry, they are also a most powerful tool for reconstructing climate change in the past. The shell of a foraminifer is a tiny gold mine of information both geometrical as chemical. However, until recently the best information on this architecture was only obtained through imaging the outside of a shell with Scanning Electron Microscopy (SEM), giving no clues towards internal structures other than single snapshots through breaking a specimen apart. With X-ray computed tomography (CT) it is possible to overcome this problem and uncover a huge amount of geometrical information without destructing the samples. Using the last generation of micro-CT's, called nano-CT, because of the sub-micron resolution, it is now possible to perform adequate imaging even on these tiny samples without needing huge facilities. In this research, a comparison is made between different X-ray sources and X-ray detectors and the resulting image resolution. Both sharpness, noise and contrast are very important parameters that will have important effects on the accuracy of the results and on the speed of data-processing. Combining this tomography technique with specific image processing software, called segmentation, it is possible to obtain a 3D virtual representation of the entire forams shell. This 3D virtual object can then be used for many purposes, from which automatic measurement of the chambers size is one of the most important ones. The segmentation process is a combination of several algorithms that are often used in CT evaluation, in this work an evaluation of those algorithms is

  20. Reconciling single-chamber Mg / Ca with whole-shell δ18O in surface to deep-dwelling planktonic foraminifera from the Mozambique Channel

    NARCIS (Netherlands)

    Steinhardt, J.; Cléroux, C.; de Nooijer, L. J.; Brummer, G. J.; Zahn, R.; Ganssen, G.; Reichart, G. J.

    2015-01-01

    Most planktonic foraminifera migrate vertically through the water column during life, meeting a range of depth-related conditions as they grow and calcify. For reconstructing past ocean conditions from geochemical signals recorded in their shells, it is therefore necessary to know vertical habitat p

  1. Reconciling single-chamber Mg / Ca with whole-shell d18O in surface to deep-dwelling planktonic foraminifera from the Mozambique Channel

    NARCIS (Netherlands)

    Steinhardt, J.; Cléroux, C.; de Nooijer, L.J.; Brummer, G.-J.A.; Zahn, R.; Ganssen, G.; Reichart, G.-J.

    2015-01-01

    Most planktonic foraminifera migrate vertically through the water column during life, meeting a range of depth-related conditions as they grow and calcify. For reconstructing past ocean conditions from geochemical signals recorded in their shells, it is therefore necessary to know vertical habitat p

  2. Benthic foraminifera from the deep-water Niger delta (Gulf of Guinea): Assessing present-day and past activity of hydrate pockmarks

    NARCIS (Netherlands)

    Fontanier, C.; Koho, K.A.; Goñi-Urriza, M.S.; Deflandre, B.; Galaup, S.; Ivanovsky, A.; Gayet, N.; Dennielou, B.; Gremare, A.; Bichon, S.; Gassie, C.; Anschutz, P.; Durán, R.; Reichart, G.J.

    2014-01-01

    We present ecological and isotopic (d18O and d13C) data on benthic foraminifera sampled from 4 deep-sea stations in a pockmark field from the deep-water Niger delta (Gulf of Guinea, Equatorial Atlantic Ocean). In addition, a series of sedimentological and (bio)geochemical data are shown to back up f

  3. Depositional Environment of the Batuasih Formation on the Basis of Foraminifera Content: A Case Study in Sukabumi Region, West Java Province, Indonesia

    Directory of Open Access Journals (Sweden)

    M. Hendrizan

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v7i2.139The research was carried out on the sediments of the Batuasih Formation cropping out at Batuasih Village, Cibatu River, Padaarang Sukabumi. Data obtained from field observation, as well as foraminifera and sedimentology analyses conducted in the laboratory, were used to interpret its depositional environment. The investigation was focused on planktonic and benthic foraminiferal assemblages for depositional environment interpretation that might not be used by previous researchers. The Batuasih Formation is composed of black shaly claystone, where the lower part is rich in clay ball, and limestone intercalations in the upper part of the formation. In Cibatu Section, no clay balls is recognized in the lower part, but intercalations of limestone still occur. However, a contrast difference is found in Padaarang section, where green claystone interbeds with fine-grained sandstone. The Batuasih Formation conformably overlies the Walat Formation containing conglomerate. Foraminifera fossil found in the Batuasih Formation consists of bad preserved black benthic and planktonic foraminifera, more abundant towards the lower part of formation. Based on foraminifera assemblage comprising genus Uvigerina, Cibicides, Elphidium, Operculina, Bulimina, Bolivina, Eponides, and Neoconorbina, supported by sedimentology data, the Batuasih Formation was deposited in a shallow to deep marine environtment, during Early Oligocene (P19 time. Upwards to be the Rajamandala Formation, the depositional environment tends to be shallower gradually.

  4. Biological results of the Snellius expedition XXX : the foraminifera collected in 1929 and 1930 in the eastern part of the Indonesian Archipelago

    NARCIS (Netherlands)

    Hofker, J.

    1978-01-01

    INTRODUCTION Of the bottom material collected by the Snellius-Expedition 78 samples contained Foraminifera. Many of these samples were extremely small, since they were gathered by means of piston core samplers; some were larger, as they were collected by means of a dredge; others were samples in sha

  5. Benthic foraminifera from the deep-water Niger delta (Gulf of Guinea) : Assessing present-day and past activity of hydrate pockmarks

    NARCIS (Netherlands)

    Fontanier, C.; Koho, K. A.; Goñi-Urriza, M. S.; Deflandre, B.; Galaup, S.; Ivanovsky, A.; Gayet, N.; Dennielou, B.; Grémare, A.; Bichon, S.; Gassie, C.; Anschutz, P.; Duran, R.; Reichart, G. J.

    2014-01-01

    We present ecological and isotopic (δ18O and δ13C) data on benthic foraminifera sampled from 4 deep-sea stations in a pockmark field from the deep-water Niger delta (Gulf of Guinea, Equatorial Atlantic Ocean). In addition, a series of sedimentological and (bio)geochemical data are shown to back up f

  6. Foraminifera and paleoenvironment of the Plio-Pleistocene Kallithea Bay section, Rhodes, Greece: Evidence for cyclic sedimentation and shallow-water sapropels

    DEFF Research Database (Denmark)

    Rasmussen, Tine Lander; Thomsen, Erik

    2005-01-01

    Nearly 250 species of benthic foraminifera have been identified from the Plio-Pleistocene strata of the Kallithea Bay section on the eastern coast of Rhodes. The section comprises an overall transgressive succession ranging from fluviatile and brackish-water gravel at the base to fine-grained dee...

  7. Carbon and nitrogen uptake of calcareous benthic foraminifera along a depth-related oxygen gradient in the OMZ of the Arabian Sea

    Directory of Open Access Journals (Sweden)

    Annekatrin Julie Enge

    2016-02-01

    Full Text Available Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with 13C and 15N by cal-careous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern Arabian Sea. The in situ tracer experiments were carried out along a depth transect on the Indian margin over a period of 4 to 10 days. The uptake of phy-todetrital carbon within 4 days by all investigated species shows that phytodetritus is a rele-vant food source for foraminifera in OMZ sediments. The decrease of total carbon uptake from 540 to 1100 m suggests a higher demand for carbon by species in the low-oxygen core region of the OMZ or less food competition with macrofauna. Especially Uvigerinids showed high uptake of phytodetrital carbon at the lowest oxygenated site. Variation in the ratio of phytodetrital carbon to nitrogen between species and sites indicates that foraminiferal carbon and nitrogen use can be decoupled and different nutritional demands are found between spe-cies. Lower ratio of phytodetrital carbon and nitrogen at 540 m could hint for greater demand or storage of food-based nitrogen, ingestion or hosting of bacteria under almost anoxic condi-tions. Shifts in the foraminiferal assemblage structure (controlled by oxygen or food availabil-ity and in the presence of other benthic organisms account for observed changes in the pro-cessing of phytodetritus in the different OMZ habitats. Foraminifera dominate the short-term processing of phytodetritus in the OMZ core but are less important in the lower OMZ bounda-ry region of the Indian margin as biological interactions and species distribution of foraminif-era change with depth and oxygen levels.

  8. Foraminifera eco-biostratigraphy of the southern Evoikos outer shelf, central Aegean Sea, during MIS 5 to present

    Science.gov (United States)

    Drinia, Hara; Antonarakou, Assimina; Tsourou, Theodora; Kontakiotis, George; Psychogiou, Maria; Anastasakis, George

    2016-09-01

    The South Evoikos Basin is a marginal basin in the Aegean Sea which receives little terrigenous supply and its sedimentation is dominated by hemipelagic processes. Late Quaternary benthic and planktonic foraminifera from core PAG-155 are investigated in order to understand their response to the glacial-interglacial cycles in this region. The quantitative analysis of planktonic foraminifera, coupled with accelerator mass spectrometry (14C-AMS) radiocarbon date measurements, provide an integrated chrono-stratigraphic time framework over the last 90 ka (time interval between late Marine Isotopic Stages 5 and 1; MIS5-MIS1). The temporary appearance and disappearance as well as several abundance peaks in the quantitative distribution of selected climate-sensitive planktonic species allowed the identification of several eco-bioevents, useful to accurately mark the boundaries of the eco-biozones widely recognized in the Mediterranean records and used for large-scale correlations. The established bio-ecozonation scheme allows a detailed palaecological reconstruction for the late Pleistocene archive in the central Aegean, and furthermore provides a notable contribution for palaeoclimatic studies, facilitating intercorrelations between various oceanographic basins. The quantitative analyses of benthic foraminifera identify four distinct assemblages, namely Biofacies: Elphidium spp., Haynesina spp. Biofacies, characterized by neritic species, dominated during the transition from MIS 5 to MIS 4; Cassidulina laevigata/carinata Biofacies dominated till 42 ka (transgressive trend from MIS 4 to MIS 3); Bulimina gibba Biofacies dominated from 42 ka to 9.5 ka (extensive regression MIS 3,2 through lowstand and early transgression; beginning of MIS 1); Bulimina marginata, Uvigerina spp. Biofacies dominated from 9.5 ka to the present (late transgression through early highstand; MIS 1)., This study showed that the South Evoikos Basin which is characterized by its critical depths and

  9. Benthic foraminifera cultured over a large salinity gradient: first results and comparison with field data from the Baltic Sea.

    Science.gov (United States)

    Groeneveld, Jeroen; Filipsson, Helena L.; Austin, William E. N.; Darling, Kate; Quintana Krupinski, Nadine B.

    2015-04-01

    Some of the most significant challenges in paleoclimate research arise from the need to both understand and reduce the uncertainty associated with proxy methods for climate reconstructions. This is especially important for shelf and coastal environments where increasing numbers of high-resolution paleorecords are being generated. These challenges are further highlighted in connection with ECORD/IODP Expedition 347: Baltic Sea Paleoenvironments. This large-scale drilling operation took place in the Baltic Sea region during the autumn of 2013. At this time, there is a pressing need for proxy calibrations directly targeted at the brackish Baltic environment. Within the CONTEMPORARY project we are investigating different temperature and salinity proxy variables through a combination of field- and culture-based benthic foraminiferal samples, together with genetic characterization (genotyping) of the morphospecies. We have completed two field campaigns where we collected (living) foraminifera and water samples at several sites, ranging from fully marine to low salinity conditions. The core-top foraminifera have been analysed for trace metal/Ca, stable oxygen and carbon isotopes, and faunal composition. Living foraminifera collected from the sediment-water interface were cultured in sea water in two long-term experiments at different temperatures (5°C and 10°C) and at three different salinities (15, 25, and 35). The first experiment yielded a large number of reproduced and experimentally-grown Elphidium specimens. The second experiment resulted in growth but no reproduction. We will provide a summary of the experimentally grown material and discuss the challenges of generating new proxy calibrations for foraminiferal shell geochemistry in the Baltic Sea. Furthermore, specimens of Elphidium and Ammonia, found at two sampling sites (Anholt, Kattegat and Hanöbay) with differing salinities, were genotyped and the results indicate that the same genotype of Elphidium is

  10. Redox sensitive elements in foraminifera from the Peruvian oxygen minimum zone

    Directory of Open Access Journals (Sweden)

    N. Glock

    2011-08-01

    Full Text Available Testing order to assess their potential as a proxy for redox conditions the element/Ca ratios of the redox sensitive elements Mn and Fe were determined in tests of benthic foraminifera from the Peruvian oxygen minimum zone (OMZ. Prior to the determination of the element/Ca ratios the distributions of Ca, Mn, Fe, Mg, Ba, Al, Si, P and S in tests of the shallow infaunal species Uvigerina peregrina and Bolivina spissa were mapped with an electron microprobe (EMP. An Fe rich phase which is also enriched in Al, Si, P and S was found on the inner test surface of U. peregrina. The element distributions of a specimen treated with an oxidative cleaning procedure show the absence of this phase. EMP maps of B. spissa also identified a similar phase which too could be removed with oxidative cleaning. Neither in B. spissa nor in U. peregrina were any hints for diagenetic (oxyhydroxide or carbonate coatings found. Mn/Ca and Fe/Ca ratios of single specimens of B. spissa from different locations have been determined by secondary ion mass spectrometry (SIMS. Bulk analyses using solution ICP-MS of several samples were compared to the SIMS data. The difference between SIMS analyses on single specimens and ICP-MS bulk analyses from the same sampling sites was 14.0–134.8 μmol mol−1 for the Fe/Ca and 1.68 μmol mol−1 for the Mn/Ca ratios. This amounts to 3–29 % for the Fe/Ca and 21.5 % for the Mn/Ca ratios of the overall variability between the samples of the different sampling sites. The Mn/Ca ratios in the calcite were generally relatively low (2.21–9.93 μmol mol−1 but of the same magnitude as in the pore waters (1.37–6.67 μmol mol−1. Comparison with sediment pore water data showed that Mn/Ca in the foraminiferal calcite is proportional to the Mn/Ca ratio in the top cm of the pore water. The lowest Fe/Ca ratio in tests of B. spissa (87.0 μmol mol

  11. Recipe Book for Larger Benthic Foraminifera X-ray Investigation: a Process Approach

    Science.gov (United States)

    Wolfgring, E.; Briguglio, A.; Hohenegger, J.

    2012-04-01

    During the past years X-ray microtomography (microCT) has become an essential tool in imaging procedures in micropaleontology. Apart from highest standards in accuracy, well conducted microCT scans aim to resolve the whole specimen in constant quality and free from any artifacts or visual interferences. Normally, to get used to X-ray techniques and get usable results, countless attempts are needed, resulting in enormous waste of time. This work tries to provide an insight into how best exploitable results can be obtained from the scanning process concerning Larger Benthic Foraminifera (LBF). As each specimen features different characteristics regarding substantial composition, density and conservation status, it is impossible and probably erroneous to give standardized guidelines even within this systematic group. Depending on the attributes of the specimen and on the desired visualization, several details have to be taken into account. Samples preparation: to get sharp images the X-ray has to cross the specimen along its shortest diameter, for LBF the equatorial view is almost always the best positioning (not for alveolinids!). The container itself has to be chosen wisely as well; it must not affect a flawless penetration of the specimen by the X-ray and has to provide a high degree of stability. Small plastic pipettes are perfect to store the specimen (or specimens) and some cardboard may help in keeping the position. The nature and quality of the paste used to fixate the object and its container are essential in ensuring a smooth rotation of the specimen which is inevitable for the consistent quality of the image and to avoid vibrations. Scan parameters: beside the correct choice of dedicated filters (which are always different depending on the working station), settings for kv, µA and resolution might have to be revised for each new object to deliver optimal results. Standard values for hyaline forms with empty chambers are normally around 80 Kv and 100 u

  12. Living (Rose-Bengal-Stained) benthic foraminifera along the Kveithola Trough (NW Barents Sea), environmental implications

    Science.gov (United States)

    Sabbatini, Anna; Morigi, Caterina; Lucchi, Renata G.; de Vittor, Cinzia; Bazzano, Matteo

    2017-04-01

    The distribution and composition of benthic foraminiferal fauna in the Kveithola Trough (NW Barents Sea) were studied in three depositional settings identified on the basis of surface depositional structures, sediment types and present ecosystem characteristics. Sediment samples were collected during the CORIBAR cruise (Hanebuth et al., 2013) aimed at drilling glacigenic sediments in a palaeo-ice stream depositional system in the western Barents Sea. In particular, we report the quantitative data of the living benthic foraminiferal density, biodiversity and vertical distribution in three box-core sediment samples (0-10 cm) collected in two inner trough sites, the drift area and the channel/fault area and one outer shelf site. Rose-Bengal-stained foraminiferal assemblages were investigated from two different size fractions (63-150 and >150 micrometres). In the drift area, the living benthic foraminiferal assemblage is characterized by the presence of oxygen-depleted environmental taxa with low foraminiferal density and biodiversity. This area appears a stagnant environment, strongly affected by low-oxygen, stressed environmental conditions in which foraminifera developed a life strategy aimed to increase the efficiency of food utilization and maximum resistance to ecological stress. As a further support to this interpretation, all the sediments recovered in the drift area are rich in organic matter and in Siboglinid-like tubes together with pockmark evidences on the surface of the box-corer. The sedimentation in the channel/fault area is very similar to that described for the drift area, evidencing stressed environmental conditions. Opportunistic species dominate the benthic foraminiferal fauna. The species distribution of the internal trough sites is consistent with the lithology and with data of quantity and biochemical composition (in terms of phytopigment, protein, lipid, carbohydrate and biopolymeric carbon) of the organic matter. Values of biopolymeric carbon

  13. Biomonitoring polluted sediments in Arctic regions - possibilities and challenges using benthic foraminifera. Case studies from northern Norway

    Science.gov (United States)

    Skirbekk, Kari; Dijkstra, Noortje; Junttila, Juho; Sternal, Beata; Pedersen, Kristine Bondo; Forwick, Matthias; Carroll, JoLynn

    2016-04-01

    Biomonitoring pollution in marine environments using benthic foraminifera assemblages have proven to be a valid method for many regions. Two important reasons for their suitability are their sensitivity to changes in the environment and their rapid response time due to short life cycles. In addition, they are preserved in the sedimentary record, allowing for baseline studies of conditions prior to introduction of contaminants. Species of benthic foraminifera that appear to tolerate polluted sediments are referred to as opportunistic species. This notion is in general used for species able to dominate environments that are too stressful for most species. The high latitude setting of the northern Norwegian coastal zone experience high seasonality and, hence, largely changing conditions throughout a year: variations in water mass domination, freshwater influence, temperature and current velocity. It is possible that an environment like this is inhibited by a higher amount of opportunistic species generally thriving under high stress conditions. This might make the use of benthic foraminifera for biomonitoring more challenging, as the faunal compositions may be a result of a complex set of processes. Consequently, large datasets are necessary in order to make reliable conclusions, which in time may be used as generalized guidelines for biomonitoring in this geographical area. Here, we present preliminary results of benthic foraminiferal assemblages from two sites in Finnmark, northern Norway, which have been exposed to pollution. The main site is Repparfjorden, where the inner parts of the fjord were used as a submarine waste deposal site for mine tailings from a local copper mine during the 1970´s. Results from four marine sediment cores (10-20 cm long) containing sediments classified to be in moderate to very bad state (according to Norwegian sediment quality criteria) are presented. The contamination is seen in intervals of elevated copper content dated to the 1970

  14. Intra-genomic ribosomal RNA polymorphism and morphological variation in Elphidium macellum suggests inter-specific hybridization in foraminifera.

    Directory of Open Access Journals (Sweden)

    Loïc Pillet

    Full Text Available Elphidium macellum is a benthic foraminifer commonly found in the Patagonian fjords. To test whether its highly variable morphotypes are ecophenotypes or different genotypes, we analysed 70 sequences of the SSU rRNA gene from 25 specimens. Unexpectedly, we identified 11 distinct ribotypes, with up to 5 ribotypes co-occurring within the same specimen. The ribotypes differ by varying blocks of sequence located at the end of stem-loop motifs in the three expansion segments specific to foraminifera. These changes, distinct from typical SNPs and indels, directly affect the structure of the expansion segments. Their mosaic distribution suggests that ribotypes originated by recombination of two or more clusters of ribosomal genes. We propose that this expansion segment polymorphism (ESP could originate from hybridization of morphologically different populations of Patagonian Elphidium. We speculate that the complex geological history of Patagonia enhanced divergence of coastal foraminiferal species and contributed to increasing genetic and morphological variation.

  15. Bone Regeneration of Rat Tibial Defect by Zinc-Tricalcium Phosphate (Zn-TCP Synthesized from Porous Foraminifera Carbonate Macrospheres

    Directory of Open Access Journals (Sweden)

    Joshua Chou

    2013-12-01

    Full Text Available Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair.

  16. Benthic foraminifera as indicators of habitat change in anthropogenically impacted coastal wetlands of the Ebro Delta (NE Iberian Peninsula).

    Science.gov (United States)

    Benito, Xavier; Trobajo, Rosa; Ibáñez, Carles; Cearreta, Alejandro; Brunet, Manola

    2015-12-15

    Present-day habitats of the Ebro Delta, NE Iberian Peninsula, have been ecologically altered as a consequence of intensive human impacts in the last two centuries (especially rice farming). Benthic foraminiferal palaeoassemblages and sediment characteristics of five short cores were used to reconstruct past wetland habitats, through application of multivariate DCA and CONISS techniques, and dissimilarity coefficients (SCD). The timing of environmental changes was compared to known natural and anthropogenic events in order to identify their possible relationships. In deltaic wetlands under altered hydrological conditions, we found a decrease in species diversity and calcareous-dominated assemblages, and a significant positive correlation between microfaunal changes and organic matter content. Modern analogues supported palaeoenvironmental interpretation of the recent evolution of the Delta wetlands. This research provides the first recent reconstruction of change in the Ebro Delta wetlands, and also illustrates the importance of benthic foraminifera for biomonitoring present and future conditions in Mediterranean deltas.

  17. Glacial-interglacial changes in the surface water characteristics of the Andaman Sea: Evidence from stable ratios of planktonic foraminifera

    Indian Academy of Sciences (India)

    S M Ahmad; D J Patil; P S Rao; B N Nath; B R Rao; G Rajagopalan

    2000-03-01

    Stable carbon and oxygen isotopic analyses of the planktonic foraminifera (Globigerinoides ruber) from a deep sea sediment core (GC-1) in the Andaman Sea show high glacial-to-Holocene 180 amplitude of 2.1% which is consistent with previously published records from this marginal basin and suggest increased salinity and/or decreased temperature in the glacial surface waters of this region. A pulse of 18O enrichment during the last deglaciation can be attributed to a Younger Dryas cooling event and/or to a sudden decrease of fresh water influx from the Irrawady and Salween rivers into the Andaman Sea. High 13C values observed during the isotopic stages 2 and 4 are probably due to the enhanced productivity during glacial times in the Andaman Sea.

  18. Major perturbations in the global carbon cycle and photosymbiont-bearing planktic foraminifera during the early Eocene

    Science.gov (United States)

    Luciani, Valeria; Dickens, Gerald R.; Backman, Jan; Fornaciari, Eliana; Giusberti, Luca; Agnini, Claudia; D'Onofrio, Roberta

    2016-04-01

    A marked switch in the abundance of the planktic foraminiferal genera Morozovella and Acarinina occurred at low-latitude sites near the start of the Early Eocene Climatic Optimum (EECO), a multi-million-year interval when Earth surface temperatures reached their Cenozoic maximum. Stable carbon and oxygen isotope data of bulk sediment are presented from across the EECO at two locations: Possagno in northeast Italy and Deep Sea Drilling Project (DSDP) Site 577 in the northwest Pacific. Relative abundances of planktic foraminifera are presented from these two locations, as well as from Ocean Drilling Program (ODP) Site 1051 in the northwest Atlantic. All three sections have good stratigraphic markers, and the δ13C records at each section can be correlated amongst each other and to δ13C records at other locations across the globe. These records show that a series of negative carbon isotope excursions (CIEs) occurred before, during and across the EECO, which is defined here as the interval between the J event and the base of Discoaster sublodoensis. Significant though ephemeral modifications in planktic foraminiferal assemblages coincide with some of the short-term CIEs, which were marked by increases in the relative abundance of Acarinina, similar to what happened across established hyperthermal events in Tethyan settings prior to the EECO. Most crucially, a temporal link exists between the onset of the EECO, carbon cycle changes during this time and the decline in Morozovella. Possible causes are manifold and may include temperature effects on photosymbiont-bearing planktic foraminifera and changes in ocean chemistry.

  19. Molecular characterization of benthic foraminifera communities from the Northeastern Gulf of Mexico shelf and slope following the Deepwater Horizon event

    Science.gov (United States)

    Moss, Joseph A.; McCurry, Chelsea; Schwing, Patrick; Jeffrey, Wade H.; Romero, Isabel C.; Hollander, David J.; Snyder, Richard A.

    2016-09-01

    Benthic foraminifera are globally distributed protozoa in the world's oceans, which have been used as ecological indicators in both current and palaeo oceanography. The ecological properties and distribution of these organisms in various regions of the Gulf of Mexico (GOM) have been evaluated using microscopy; however molecular approaches for these purposes have been limited, especially in deeper regions. The BP Deepwater Horizon oil well failure in the northern Gulf of Mexico highlighted the need to better understand the distribution and abundance of these organisms relative to environmental factors and ecosystem perturbations such as the oil spill. Sediment samples were collected using a Shipek grab along transects on the northwest Florida GOM shelf (18-270 m depth). Clone libraries were developed from PCR amplified 18S rDNA genes for sequence analysis. Analysis of random clones from libraries were used as a proxy for community structure (presence and relative abundance) to document the spatial and temporal dynamics of benthic foraminifera on the Northwest Florida Shelf in the NE GOM shelf. Additional continental slope samples (200-1600 m depth) were obtained by a multicorer and treated in similar fashion. Mean species diversity in this study (H=2.49-3.36), agreed with pre-DWH event estimates, however the dominant agglutinated species in the deep-water samples did not match previous studies. Additionally, the dominant calcareous taxa from this study such as Allogromida sp. and Psammophaga sp., were inconsistent with previous reports. The dominant taxa in both coastal and deep-water sites include Glabratellina sp., Trochammina hadai, and Trochammina sp., and Textularia sagittula and Bathysiphon argenteus as well as members of genera Astrammina, Bolivina, Cibicides and Cibicidoides.

  20. Calibration and application of the ‘clumped isotope’ thermometer to foraminifera for high-resolution climate reconstructions

    Science.gov (United States)

    Grauel, Anna-Lena; Schmid, Thomas W.; Hu, Bin; Bergami, Caterina; Capotondi, Lucilla; Zhou, Liping; Bernasconi, Stefano M.

    2013-05-01

    The reconstruction of past ocean temperatures is fundamental to the study of past climate changes, therefore considerable effort has been invested in developing proxies for seawater temperatures. One of the most recent and promising new proxy is carbonate ‘clumped isotope’ thermometry, in particular because it is based on thermodynamic equilibrium and not on biogeochemical proxies. Here, we present a new calibration of the ‘clumped isotope’ thermometer to foraminifera based on seven species of planktic and benthic foraminifera spanning a growth temperature range of ∼2-28 °C. We used a newly developed technique for the measurements of small samples to improve the applicability of this method to paleoceanography. Our data have a comparable precision (∼0.005-0.013‰) and confirm previous calibration studies based on biogenic and inorganic calcite. We discuss possible sources of uncertainty such as over-/underestimation of the calcification temperatures, species-specific vital effects, pH variations between the seawater and the vacuole water of the species and possible kinetic effects on the ‘clumped isotope’ calibration. To validate our calibration study and test the applicability of our measuring technique to paleoclimate and paleoceanographic studies we measured the isotope composition of Globigerinoides ruber (white) at high-resolution in a sediment core covering the last 700 years in the Gulf of Taranto (Mediterranean Sea). The results show that it is necessary to average a relatively large number of analyses to achieve a consistent temperature signal for the detection of small sea surface temperature changes. Although with the current analytical system, ‘clumped isotope’ thermometry is only applicable to the analysis of relatively large SST changes in marine sediments, further technical improvements may make this a very powerful technique for paleoceanographic studies.

  1. Temporal size changes of Miocene planktonic foraminifera Paragloborotalia siakensis in the eastern Equatorial Pacific associated with Mi-events

    Science.gov (United States)

    Okada, H.; Hayashi, H.

    2013-12-01

    Temporal changes in test size of planktonic foraminifera have been variously studied as a key for knowing evolution related to paleoceanographic changes. With respect to recent studies, rapid size reducing ('dwarfing') in several species have been observed around the last occurrence horizon. Generically, size changes of calcareous nannofossils have been used for global correlation. However, there are few previous studies of such temporal size changes for Miocene planktonic foraminifera. Paragloborotalia siakensis (LeRoy, 1939) is one of important index species in the middle Miocene. The upper boundary of planktonic foraminieral Zone N.14 is defined by the top occurrence of this species. It is a well known fact that P. siakensis is a dominant species in the tropical high-productivity area such as the eastern equatorial Pacific. The aims of this study are to reveal size changes of P. siakensis collected from IODP Site U1338 in the eastern equatorial Pacific and to correlate the size changes with paleoceanographic events. We measured maximum length of P. siakensis (50-200 individuals for each horizon) at approximately every 0.1 million years from 16.0 to 10.5 Ma. At the same time, we also conducted morphometric analyses of selected five horizons (14.96 Ma, 14.03 Ma, 13.00 Ma, 12.29 Ma and 11.11 Ma) by means of image analysis software (ImageJ). According to the morphometric analyses, the population from Site U1338 should be compared with the holotype of P. siakensis. The maximum length of P. siakensis shows significant reducing ('dwarfing') at cooling intervals inferred by previous studies based on alkenone and isotope data. It is possible to say that dwarfing of P. siakensis at Site U1338 might be induced by shallowing of the thermocline in the eastern equatorial Pacific.

  2. Reworked planktonic Foraminifera from the Late Rupelian of the southern Upper Rhine Graben and their palaeogeographic and biostratigraphic implications

    Science.gov (United States)

    Pirkenseer, C.; Spezzaferri, S.; Berger, J.-P.

    2009-04-01

    During the Late Rupelian the widespread second transgression (corresponding to international Ru2-3 transgressions; BERGER et al. 2005) affected the whole Upper Rhine Graben basin and led to the deposition of the several hundred meters thick marine "Série grise". An abrupt transition (erosion surface) between the uppermost "Série grise" and Niederroedern Formation indicates the change to fluviatile and lacustrine conditions throughout the basin close to the Late Rupelian / Early Chattian boundary. Abundant reworked Middle to Late Cretaceous (e.g., Marginotruncana pseudolinneiana) and Late Paleocene to Late Eocene (e.g., Acarinina bullbrooki, Morozovella subbotinae, Turborotalia cocoaensis) ranging planktonic Foraminifera occur in the "Série Grise" and equivalent lithological units of the Upper Rhine Graben and the Mainz Basin (e.g., FISCHER 1965, PIRKENSEER 2007, SCHÄFER & KUHN 2004). At least Late Cretaceous, Ypresian, Lutetian and Priabonian ages of source sediments are indicated by the overlapping biostratigraphic ranges of the reworked specimens. Abundant reworked material first appears in the lower "Couches à Mélettes" and reaches its acme in the increasingly "Marnes à Cyrènes" (terminal "Série grise"). Only sparse records are documented from the subsequent terrestrial Niederroedern Formation. These reworking events are linked to intervals of increased clastic input throughout the "Série grise". The planktonic Foraminifera are proposed to be reworked from related alpine deposits (later Helvetikum?) via a northwards trending fluviatile system, as no autochthonous Cretaceous and Early to Middle Eocene marine sediments were deposited within the graben basin. Furthermore other possible source areas (e.g., Paris Basin) were either not connected to the Upper Rhine Graben or were not subject to erosion in the Late Rupelian. This accords with the proposition (ROUSSÉ 2006) of a vast northwards prograding delta-system that was located close to the southern

  3. Late Aptian-Albian of the Vocontian Basin (SE-France) and Albian of NE-Texas: Biostratigraphic and paleoceanographic implications by planktic foraminifera faunas

    OpenAIRE

    Reichelt, Kerstin

    2005-01-01

    Planktic foraminifera fauna and carbon isotopes of the bulk rock have been investigated to compile a high resolution biostratigraphy for the Late Aptian to Late Albian in the Vocontian Basin (SE-France) and for the Middle and Late Albian in NE-Texas. A high resolution carbon isotope stratigraphy (CIS) has been established for the Albian of the Vocontian Basin, and partially correlated with sections in the eastern (ODP 547, Mazagan Plateau) and western (ODP 1052; Blake Nose Plateau) Atlantic a...

  4. Relative utility of foraminifera, diatoms and macrophytes as high resolution indicators of paleo-sea level in coastal British Columbia, Canada

    Science.gov (United States)

    Patterson, R. Timothy; Dalby, Andrew P.; Roe, Helen M.; Guilbault, Jean-Pierre; Hutchinson, Ian; Clague, John J.

    2005-10-01

    A multiproxy analysis was carried out on diatom, foraminiferal and macrophyte assemblages across the saltmarsh at Zeballos, Vancouver Island, British Columbia. To determine which group, or combination of groups provided the most accurate elevational zonations, 36 stepwise multiple linear regressions (SMLR) were carried out using a variety of data transformations on an elevational training set. Adjusted R2 values yielded statistically significant results in all analyses as follows: foraminifera (0.658-0.870); diatoms (0.888-0.974); macrophytes (0.671-0.844); foraminifera/diatoms (0.941-0.981); foraminifera/diatoms/macrophytes (0.958-0.993). The most realistic SMLR results were obtained when data transformations comprised of (ln) normalized fractional abundance data was carried out on species present in statistically significant numbers (NrfaEQ). Of the individual proxies assessed, diatoms yielded the most significant adjusted R2 results, with the low marsh diatom Achnanthes hauckiana being one of the most important predictor variables (pv's). Amongst the foraminifera, the low marsh species Miliammina fusca and high marsh Balticammina pseudomacrescens were determined to be the most significant pv's. For macrophytes, the low marsh species Carex lyngbyei, the high marsh species Juncus balticus, Shannon-Wiener Diversity Index (SDI) and absence of plant cover on the tidal flat were the most important pv's. As SMLR analysis of all individual groups and combinations of groups yielded statistically significant results, the choice of proxies, or combinations of proxies that are suitable for paleo-sea level research is at the discretion of the researcher.

  5. PFR²: a curated database of planktonic foraminifera 18S ribosomal DNA as a resource for studies of plankton ecology, biogeography and evolution.

    Science.gov (United States)

    Morard, Raphaël; Darling, Kate F; Mahé, Frédéric; Audic, Stéphane; Ujiié, Yurika; Weiner, Agnes K M; André, Aurore; Seears, Heidi A; Wade, Christopher M; Quillévéré, Frédéric; Douady, Christophe J; Escarguel, Gilles; de Garidel-Thoron, Thibault; Siccha, Michael; Kucera, Michal; de Vargas, Colomban

    2015-11-01

    Planktonic foraminifera (Rhizaria) are ubiquitous marine pelagic protists producing calcareous shells with conspicuous morphology. They play an important role in the marine carbon cycle, and their exceptional fossil record serves as the basis for biochronostratigraphy and past climate reconstructions. A major worldwide sampling effort over the last two decades has resulted in the establishment of multiple large collections of cryopreserved individual planktonic foraminifera samples. Thousands of 18S rDNA partial sequences have been generated, representing all major known morphological taxa across their worldwide oceanic range. This comprehensive data coverage provides an opportunity to assess patterns of molecular ecology and evolution in a holistic way for an entire group of planktonic protists. We combined all available published and unpublished genetic data to build PFR(2), the Planktonic foraminifera Ribosomal Reference database. The first version of the database includes 3322 reference 18S rDNA sequences belonging to 32 of the 47 known morphospecies of extant planktonic foraminifera, collected from 460 oceanic stations. All sequences have been rigorously taxonomically curated using a six-rank annotation system fully resolved to the morphological species level and linked to a series of metadata. The PFR(2) website, available at http://pfr2.sb-roscoff.fr, allows downloading the entire database or specific sections, as well as the identification of new planktonic foraminiferal sequences. Its novel, fully documented curation process integrates advances in morphological and molecular taxonomy. It allows for an increase in its taxonomic resolution and assures that integrity is maintained by including a complete contingency tracking of annotations and assuring that the annotations remain internally consistent.

  6. Impact of relative sea level and extreme climate events on the Southern Skhira coastline (Gulf of Gabes, Tunisia) during Holocene times: Ostracodes and foraminifera associations' response

    Science.gov (United States)

    Zaïbi, Chahira; Kamoun, Fekri; Viehberg, Finn; Carbonel, Pierre; Jedoui, Younes; Abida, Habib; Fontugny, Michel

    2016-06-01

    This study examines the evolution of the Skhira coast (Southeastern Tunisia) during Holocene times, by analyzing ostracodes, foraminifera and mollusk associations in subsurface sediments of both sebkhas of Dreîaa and El Guettiate. Nine biofacies represented by (1) five categories of lagoon namely widely opened, opened, brackish estuarine, closed and emerged; (2) the maximum of closure of environment revealed by continental and sebkha biofacies; (3) a peculiar two biofacies, formed by coarse sands or shelly clays and dominated by mollusk fragments and showing a mixture of lagoonal, marine and brackish taxa of mollusk, ostracods and foraminifera which provide evidence of high energy events (storms). The lower Holocene continental sediments are overlain by two transgressive categories of biofacies. The first one corresponds to a widely opened lagoon biofacies, related to the first Holocene marine transgression, around 7.46 ka cal BP. The second one, more important, consists of an opened lagoon biofacies between 6.67 and 5.91 ka cal BP. Sudden changes, during Holocene time, in the numerical distribution of foraminifera and ostracods species up cores are used to infer the change from widely opened lagoon, subjected to estuarine influences, to sebkha by passing by a close lagoonal environment. The enrichment of the sediment in quartz grains coupled with the action of the current drift authorized the build-up of sandy spits in front of the estuaries and the genesis of lagoon that preserve a rich assemblage of euryhaline foraminifera, ostracods and mollusks species. This process was interrupted by two distinct high-energy events. The break of sand spits induced the introduction of washover clay deposits at 5.418 ka cal BP and washover coarse sands at 644 a cal BP rich in mixture of brackish and marine macrofauna and microfauna.

  7. Foraminifera And Coccolithophorid Assemblage Changes In The Panama Basin During The Last Deglaciation: Response To Sea-Surface Productivity Induced By A Transient Climate Change

    Science.gov (United States)

    Martinez, I.; Rincon, D.; Yokoyama, Y.; Barrows, T.

    2004-12-01

    The response of community assemblages of planktonic and benthonic foraminifera and coccolithophorids to transient climate change are explored for the uppermost 2m of cores ODP677B (1.2°N; 83.74°W, 3461m) and TR163-38 (1.34°S; 81.58°W, 2200m), for the last ~40ka. Results suggest that the deglaciation interval was a time of increased productivity and a major reorganization of planktonic trophic webs. The succession in dominance of planktonic foraminifera species Globorotalia inflata, Globigerina bulloides, and Neogloboquadrina pachyderma denote four periods of oceanographic change: (1) advection (24 to 20ka), (2) strong upwelling (20 to 15ka), (3) weak upwelling (14 to 8ka) and (4) oligotrophy (8ka to Present). Strong upwelling for the deglaciation interval is supported by the low Florisphaera profunda / other coccolithophorids ratio and the high percentage abundance of Gephyrocapsa oceanica. Benthonic foraminifera assemblage changes are different in both cores and suggest significant regional variations in surface productivity and/or oxygen content at the seafloor, and a decoupling between surface productivity and export production to the seafloor. This decoupling is evidenced by the inverse relationship between the percentage abundance of infaunal benthonic foraminifera and the percentage abundance of N. pachyderma. The terrigenous input of the Colombian Pacific rivers, particularly the San Juan River, is suggested as a possible mechanism. Finally, the Globorotalia cultrata /Neogloboquadrina dutertrei ratio, is used to reconstruct the past influence of the Costa Rica Dome - Panama Bight and cold tongue upwelling systems in the Panama Basin. A northern influence is suggested for the late Holocene (after 5ka), and the last glacial (before 20ka), whereas a southern influence is suggested for the 20 to 5ka interval. There is a correspondence between our reconstructed northern and southern influences and previously proposed positions of the Intertropical Convergence

  8. Preservation of benthic foraminifera and reliability of deep-sea temperature records: Importance of sedimentation rates, lithology, and the need to examine test wall structure

    Science.gov (United States)

    Sexton, Philip F.; Wilson, Paul A.

    2009-06-01

    Preservation of planktic foraminiferal calcite has received widespread attention in recent years, but the taphonomy of benthic foraminiferal calcite and its influence on the deep-sea palaeotemperature record have gone comparatively unreported. Numerical modeling indicates that the carbonate recrystallization histories of deep-sea sections are dominated by events in their early burial history, meaning that the degree of exchange between sediments and pore fluids during the early postburial phase holds the key to determining the palaeotemperature significance of diagenetic alteration of benthic foraminifera. Postburial sedimentation rate and lithology are likely to be important determinants of the paleoceanographic significance of this sediment-pore fluid interaction. Here we report an investigation of the impact of extreme change in sedimentation rate (a prolonged and widespread Upper Cretaceous hiatus in the North Atlantic Ocean) on the preservation and δ18O of benthic foraminifera of Middle Cretaceous age (nannofossil zone NC10, uppermost Albian/lowermost Cenomanian, ˜99 Ma ago) from multiple drill sites. At sites where this hiatus immediately overlies NC10, benthic foraminifera appear to display at least moderate preservation of the whole test. However, on closer inspection, these tests are shown to be extremely poorly preserved internally and yield δ18O values substantially higher than those from contemporaneous better preserved benthic foraminifera at sites without an immediately overlying hiatus. These high δ18O values are interpreted to indicate alteration close to the seafloor in cooler waters during the Late Cretaceous hiatus. Intersite differences in lithology modulate the diagenetic impact of this extreme change in sedimentation rate. Our results highlight the importance of thorough examination of benthic foraminiferal wall structures and lend support to the view that sedimentation rate and lithology are key factors controlling the paleoceanographic

  9. Benthic foraminifera records of complex anthropogenic environmental changes combined with geochemical data in a tropical bay of New Caledonia (SW Pacific)

    OpenAIRE

    Debenay, Jean-Pierre; Fernandez, J. P.

    2009-01-01

    During the 1950s, open-cast mining led to an increasing input of heavy-metal-rich terrigenous particles in the bays near Noumea, detected by geochemical and sedimentological analyses. Even though most of terrigenous metal is unavailable, an impact on the benthos was suspected. Simultaneously, the population of Noumea increased dramatically, which may impact the neighboring bays. Foraminifera were used for assessing this double impact. Thirteen surface samples were collected as a basis for the...

  10. Late Aptian-Albian of the Vocontian Basin (SE-France) and Albian of NE-Texas: Biostratigraphic and paleoceanographic implications by planktic foraminifera faunas

    OpenAIRE

    Reichelt, Kerstin

    2005-01-01

    Planktic foraminifera fauna and carbon isotopes of the bulk rock have been investigated to compile a high resolution biostratigraphy for the Late Aptian to Late Albian in the Vocontian Basin (SE-France) and for the Middle and Late Albian in NE-Texas. A high resolution carbon isotope stratigraphy (CIS) has been established for the Albian of the Vocontian Basin, and partially correlated with sections in the eastern (ODP 547, Mazagan Plateau) and western (ODP 1052; Blake Nose Plateau) Atlantic a...

  11. Carbonate system and salinity controls on B/Ca of tropical and subtropical planktic foraminifera: Insight from culture experiments

    Science.gov (United States)

    Allen, K. A.; Hoenisch, B.; Eggins, S. M.; Rosenthal, Y.

    2011-12-01

    Characterizing past surface ocean carbonate chemistry can give us insight into the role of CO2 in driving and/or amplifying climate change. Recently, the ratio of boron to calcium (B/Ca) in the calcite tests of planktic foraminifera has been investigated as a proxy for the seawater carbonate system. Because borate is the dissolved B species dominantly incorporated into carbonates, and its aqueous concentration increases with seawater pH, the boron concentration of carbonates is also expected to increase with seawater pH. However, results from core tops and sediment traps yield different results for different species, and additional controls of temperature and carbonate ion have been suggested. Here, we present data from laboratory culture experiments with three planktic foraminifer species: the tropical Globigerinoides sacculifer, Globigerinoides ruber (pink), and the subtropical-temperate Orbulina universa. Calibrations of G. sacculifer and G. ruber against temperature, salinity, pH, and carbonate ion were performed in Puerto Rico in 2010; O. universa were cultured on Catalina Island, CA in 2008. For each experiment, light, water temperature, and seawater chemistry are tightly controlled, allowing us to vary one parameter at a time. Similar to core-top studies, we find that average B/Ca of the three species are offset, but the species' response to environmental variables is more uniform than previously suggested. B/Ca in all species increases with salinity, but not with temperature. We also experimentally separated the relative influence of pH and carbonate ion on B incorporation and found that B/Ca increases in response to a paired increase in pH and carbonate ion, but B/Ca decreases when carbonate ion is raised while pH (and thus borate) are held constant. This suggests that borate and carbonate ions may compete for inclusion in the calcite lattice, and that their relative abundance in seawater directly influences B/Ca of planktic foraminifera. More work is

  12. Cyanobacterial endobionts within a major marine planktonic calcifier (Globigerina bulloides, Foraminifera) revealed by 16S rRNA metabarcoding

    Science.gov (United States)

    Bird, Clare; Darling, Kate F.; Russell, Ann D.; Davis, Catherine V.; Fehrenbacher, Jennifer; Free, Andrew; Wyman, Michael; Ngwenya, Bryne T.

    2017-02-01

    We investigated the possibility of bacterial symbiosis in Globigerina bulloides, a palaeoceanographically important, planktonic foraminifer. This marine protist is commonly used in micropalaeontological investigations of climatically sensitive subpolar and temperate water masses as well as wind-driven upwelling regions of the world's oceans. G. bulloides is unusual because it lacks the protist algal symbionts that are often found in other spinose species. In addition, it has a large offset in its stable carbon and oxygen isotopic compositions compared to other planktonic foraminifer species, and also that predicted from seawater equilibrium. This is suggestive of novel differences in ecology and life history of G. bulloides, making it a good candidate for investigating the potential for bacterial symbiosis as a contributory factor influencing shell calcification. Such information is essential to evaluate fully the potential response of G. bulloides to ocean acidification and climate change. To investigate possible ecological interactions between G. bulloides and marine bacteria, 18S rRNA gene sequencing, fluorescence microscopy, 16S rRNA gene metabarcoding and transmission electron microscopy (TEM) were performed on individual specimens of G. bulloides (type IId) collected from two locations in the California Current. Intracellular DNA extracted from five G. bulloides specimens was subjected to 16S rRNA gene metabarcoding and, remarkably, 37-87 % of all 16S rRNA gene sequences recovered were assigned to operational taxonomic units (OTUs) from the picocyanobacterium Synechococcus. This finding was supported by TEM observations of intact Synechococcus cells in both the cytoplasm and vacuoles of G. bulloides. Their concentrations were up to 4 orders of magnitude greater inside the foraminifera than those reported for the California Current water column and approximately 5 % of the intracellular Synechococcus cells observed were undergoing cell division. This suggests

  13. Tolerance of allogromiid Foraminifera to severely elevated carbon dioxide concentrations: Implications to future ecosystem functioning and paleoceanographic interpretations

    Science.gov (United States)

    Bernhard, Joan M.; Mollo-Christensen, Elizabeth; Eisenkolb, Nadine; Starczak, Victoria R.

    2009-02-01

    Increases in the partial pressure of carbon dioxide (pCO 2) in the atmosphere will significantly affect a wide variety of terrestrial fauna and flora. Because of tight atmospheric-oceanic coupling, shallow-water marine species are also expected to be affected by increases in atmospheric carbon dioxide concentrations. One proposed way to slow increases in atmospheric pCO 2 is to sequester CO 2 in the deep sea. Thus, over the next few centuries marine species will be exposed to changing seawater chemistry caused by ocean-atmospheric exchange and/or deep-ocean sequestration. This initial case study on one allogromiid foraminiferal species ( Allogromia laticollaris) was conducted to begin to ascertain the effect of elevated pCO 2 on benthic Foraminifera, which are a major meiofaunal constituent of shallow- and deep-water marine communities. Cultures of this thecate foraminiferan protist were used for 10-14-day experiments. Experimental treatments were executed in an incubator that controlled CO 2 (15 000; 30 000; 60 000; 90 000; 200 000 ppm), temperature and humidity; atmospheric controls (i.e., ~ 375 ppm CO 2) were executed simultaneously. Although the experimental elevated pCO 2 values are far above foreseeable surface water pCO 2, they were selected to represent the spectrum of conditions expected for the benthos if deep-sea CO 2 sequestration becomes a reality. Survival was assessed in two independent ways: pseudopodial presence/absence and measurement of adenosine triphosphate (ATP), which is an indicator of cellular energy. Substantial proportions of A. laticollaris populations survived 200 000 ppm CO 2 although the mean of the median [ATP] of survivors was statistically lower for this treatment than for that of atmospheric control specimens. After individuals that had been incubated in 200 000 ppm CO 2 for 12 days were transferred to atmospheric conditions for ~ 24 h, the [ATP] of live specimens (survivors) approximated those of the comparable atmospheric

  14. Comparisons of the ecology and stable isotopic compositions of living (stained) benthic foraminifera from the Sulu and South China Seas

    Science.gov (United States)

    Rathburn, A. E.; Corliss, B. H.; Tappa, K. D.; Lohmann, K. C.

    1996-10-01

    Significant differences are observed between living (Rose Bengal stained) deep-sea benthic foraminifera found in 14 box cores (510-4515 m) from the thermospheric (> 10°C) environments of the Sulu Sea and the psychrospheric ( 2‰ range and are similar to those presented by previous workers, but have no consistent relationship with microhabitat preferences. Vertical distribution patterns and carbon isotope compositions of species, however, reflect microhabitat preferences and are consistent with previous observations from other regions. Epifaunal species (0-1 cm interval) such as Cibicidoides pachyderma, Cibicidoides wuellerstorfi, Hoeglundina elegans and Anomalinoides colligera, have higher δ13C values than taxa which have the ability to live deeper within the sediments. Infaunal taxa that live in the upper 2-3 cm, including Uvigerina peregrina, Uvigerina proboscidea, and Bulimina mexicana, have lower δ13C values than epifaunal species, and the deep infaunal species, Chilostomella oolina, has the lowest δ13C. Cibicidoides bradyi and Oridorsalis umbonatus are found between 0 and ˜ 4 cm and have lower carbon isotope values (by > 1.4‰ in some cores) than epifaunal Cibicidoides species. Exceptions to this pattern include the aragonitic species, Gavelinopsis lobatulus, (0-4 cm) which produces significantly lower δ13C values than deep infaunal taxa, and the shallow infaunal species, Ceratobulimina pacifica (also aragonitic) and Bolivinopsis cubensis (deep infaunal), which yield higher carbon isotopic values than epifaunal taxa. These exceptions are found primarily in only one core, and additional samples are needed to confirm the relationship between their distribution patterns and isotopic compositions. Each of the species examined has a relatively consistent δ13C value throughout its distribution within the sediments that may result from heterogeneity of microhabitats within the intervals sampled. Intrageneric differences in δ13C of Cibicidoides, and possibly

  15. Geochemical signatures of benthic foraminifera shells from a heat-polluted shallow marine environment provide field evidence for growth and calcification under extreme warmth

    Science.gov (United States)

    Titelboim, Danna; Sadekov, Aleksey; Almogi-Labin, Ahuva; Herut, Barak; Kucera, Michal; Schmidt, Christiane; Hyams-Kaphzan, Orit; Abramovich, Sigal

    2017-04-01

    Shallow marine calcifiers play an important role as marine ecosystem engineers and in the global carbon cycle. Understanding their response to warming is essential to evaluate the fate of marine ecosystems under global change scenarios. So far, most data on thermal tolerance of marine calcifiers have been obtained by manipulative laboratory experiments. Such experiments provide valuable physiological data, but it remains unclear to what degree these observations apply to natural ecosystems. A rare opportunity to test the effect of warming acting on ecosystem-relevant scales is by investigation of heat-polluted coastal areas. Here we study growth and calcification in benthic foraminifera that inhabit a thermally polluted coastal area in Israel, where they are exposed to temperature elevated by 6˚ C above the natural seasonal temperature range and reaching up to ˜42˚ C in summer. Several species of benthic foraminifera have been previously shown to persist throughout the year in the heat-polluted area, allowing us to examine in natural conditions the thermal limits of growth and calcification under extreme temperatures as they are expected to prevail in the future. Live specimens of two known heat tolerant species Lachlanella sp. 1 and Pararotalia calcariformata were collected over a period of one year from two stations, representing thermally polluted and undisturbed (control) shallow hard bottom habitats. Single-chamber element ratios of these specimens were obtained using laser ablation and the Mg/Ca of the last chambers (grown closest to the time of collection) were used to calculate calcification temperatures. Our results provide the first direct field evidence that these foraminifera species not only persist extreme warm temperatures but continue to grow and calcify. Species-specific Mg/Ca thermometry indicates that P. calcariformata precipitate their shells at temperatures as high as 40˚ C and Lachlanella sp. 1 at least up to 36˚ C. Instead, both species

  16. Benthic foraminifera as tools in interpretation of subsurface hydrocarbon fluid flow at Veslemøy High and Hola-Vesterålen areas of the Barents Sea.

    Science.gov (United States)

    Baranwal, Soma; Sauer, Simone; Knies, Jochen; Chand, Shyam; Jensen, Henning; Klug, Martin

    2014-05-01

    Relatively few studies have focused on high-latitude benthic foraminifera related to hydrocarbon seeps. In this study, we present micropaleontological data from 8 gravity cores from the Veslemøy High and 4 surface sediments (0-1cm) from Hola-Vesterålen, Norway. The study of hydrocarbon impregnation and its effect on benthic foraminfera was conducted on selected sediment samples from the calcium-rich Holocene sediments of the Veslemøy High. The assemblage of foraminifera have been identified from three regional clusters. Cluster I and II are dominated by benthic foraminifera Buccella, Cassidulina, Cibicides, Discopulvinulina, Epistominella, Pullenia and Trifarina. Cluster III is distinct with an elevated abundance of Cassidulina, Cibicides and Trifarina with significant (>5 %) occurrence of Nonionella and Uvigerina. There is no apparent dissolution on the preserved foraminifera. However, there can be differential dissolution or destruction of the more fragile (thinner-walled test) species like Epistominella, Nonionella or Pullenia while leaving behind over-represented species like Cibicides or Trifarina (both preferring coarse grained, high energy areas that can withstand permanent winnowing and redeposition) with higher preservation potential. Also, Cluster III is placed right over the underlying fault line with shallow seep-indications and thus the fluids released may have induced the dissolution of the fragile species. Moreover, the significant occurrence of benthic foraminifera Nonionella auris, and Uvigerina peregrina, in Holocene deposits of Cluster III may be indicative of environments influenced by hydrocarbon migration to the seafloor. Previous studies have reported active natural hydrocarbon seepage in the Hola area and the stable carbon and hydrogen isotopic composition of methane in the sediments suggests a predominantly thermogenic methane source. The seep-assemblage is composed of Cibicides (~60%), Cassidulina, Discanomalina, Textularia and

  17. Can benthic foraminifera be used as bio-indicators of pollution in areas with a wide range of physicochemical variability?

    Science.gov (United States)

    Martins, Maria Virgínia Alves; Pinto, Anita Fernandes Souza; Frontalini, Fabrizio; da Fonseca, Maria Clara Machado; Terroso, Denise Lara; Laut, Lazaro Luiz Mattos; Zaaboub, Noureddine; da Conceição Rodrigues, Maria Antonieta; Rocha, Fernando

    2016-12-01

    The Ria de Aveiro, a lagoon located in the NW coast of Portugal, presents a wide range of changes to the natural hydrodynamical and physicochemical conditions induced for instance by works of port engineering and pollution. In order to evaluate the response of living benthic foraminifera to the fluctuations in physicochemical parameters and pollution (metals and TOC), eight sediment samples were collected from canals and salt pans within the Aveiro City, in four different sampling events. During the sampling events, salinity showed the most significant fluctuations among the physicochemical parameters with the maximum range of variation at Troncalhada and Santiago salt pans. Species such as Haynesina germanica, Trochammina inflata and Entzia macrescens were found inhabiting these hypersaline environments with the widest fluctuations of physicochemical parameters. In contrast, Ammonia tepida dominated zones with high concentrations of metals and organic matter and in lower salinity waters. Parameters related to benthic foraminiferal assemblages (i.e., diversity and evenness) were found to significantly decline in stations polluted by metals and characterized by higher TOC content. Foraminiferal density reduced significantly in locations with a wide range of physicochemical temporal variability. This work shows that, even under extreme conditions caused by highly variable physicochemical parameters, benthic foraminiferal assemblages might be used as valuable bioindicators of environmental stress.

  18. Intracellular isotope localization in Ammonia sp. (Foraminifera of oxygen-depleted environments: results of nitrate and sulfate labeling experiments

    Directory of Open Access Journals (Sweden)

    Hidetaka eNomaki

    2016-02-01

    Full Text Available Some benthic foraminiferal species are reportedly capable of nitrate storage and denitrification, however, little is known about nitrate incorporation and subsequent utilization of nitrate within their cell. In this study, we investigated where and how much 15N or 34S were assimilated into foraminiferal cells or possible endobionts after incubation with isotopically labeled nitrate and sulfate in dysoxic or anoxic conditions. After two weeks of incubation, foraminiferal specimens were fixed and prepared for Transmission Electron Microscopy (TEM and correlative nanometer-scale secondary ion mass spectrometry (NanoSIMS analyses. TEM observations revealed that there were characteristic ultrastructural features typically near the cell periphery in the youngest two or three chambers of the foraminifera exposed to anoxic conditions. These structures, which are electron dense and ~200 to 500 nm in diameter and co-occurred with possible endobionts, were labeled with 15N originated from 15N-labeled nitrate under anoxia and were labeled with both 15N and 34S under dysoxia. The labeling with 15N was more apparent in specimens from the dysoxic incubation, suggesting higher foraminiferal activity or increased availability of the label during exposure to oxygen depletion than to anoxia. Our results suggest that the electron dense bodies in Ammonia sp. play a significant role in nitrate incorporation and/or subsequent nitrogen assimilation during exposure to dysoxic to anoxic conditions.

  19. Glomospirella cantabrica n. sp., and other benthic foraminifera from Lower Cretaceous Urgonian-type carbonates of Cantabria, Spain: Biostratigraphic implications

    Energy Technology Data Exchange (ETDEWEB)

    Schlagintweit, F.; Rosales, I.; Najarro, M.

    2016-07-01

    A new benthic foraminifer is described as Glomospirella cantabrica n. sp. from several sections of the upper Aptian Reocín Formation and one occurrence from the lowermost Albian Las Peñosas Formation of Cantabria (northern Spain). It represents a rather large-sized Glomospirella, with up to eight planispiral whorls, observed in lagoonal wackestones and packstones. The upper Aptian (upper Gargasian–Clansayesian) age is indicated by the co-occurrence with other benthic foraminifera, i.e. orbitolinids. Further biostratigraphic data of the Aptian-p.p. Albian shallow-water carbonates of the North Cantabrian Basin is provided. The rareness of dasycladalean green algae in these deposits is also highlighted. The resulting stratigraphic and biostratigraphic scheme is integrated in a framework of depositional sequences of the North Cantabrian Basin and compared with the sequential schemes of other areas of the Basque-Cantabrian Basin and the Iberian Chain. Similitudes suggest that these depositional sequences are related to global sea-level changes. (Author)

  20. Characterizing the variability of benthic foraminifera in the northeastern Gulf of Mexico following the Deepwater Horizon event (2010-2012).

    Science.gov (United States)

    Schwing, P T; O'Malley, B J; Romero, I C; Martínez-Colón, M; Hastings, D W; Glabach, M A; Hladky, E M; Greco, A; Hollander, D J

    2017-01-01

    Following the Deepwater Horizon (DWH) event in 2010 subsurface hydrocarbon intrusions (1000-1300 m) and an order of magnitude increase in flocculent hydrocarbon deposition caused increased concentrations of hydrocarbons in continental slope sediments. This study sought to characterize the variability [density, Fisher's alpha (S), equitability (E), Shannon (H)] of benthic foraminifera following the DWH event. A series of sediment cores were collected at two sites in the northeastern Gulf of Mexico from 2010 to 2012. At each site, three cores were utilized for benthic faunal analysis, organic geochemistry, and redox metal chemistry, respectively. The surface intervals (∼0-10 mm) of the sedimentary records collected in December 2010 at DSH08 and February 2011 at PCB06 were characterized by significant decreases in foraminiferal density, S, E, and H, relative to the down-core intervals as well as previous surveys. Non-metric multidimensional scaling (nMDS) analysis suggested that a 3-fold increase in polycyclic aromatic hydrocarbon (PAH) concentration in the surface interval, relative to the down-core interval, was the environmental driver of benthic foraminiferal variability. These records suggested that the benthic foraminiferal recovery time, following an event such as the DWH, was on the order of 1-2 years.

  1. Assessment of the impacts of trace metals on benthic foraminifera in surface sediments from the northwestern Taiwan Strait.

    Science.gov (United States)

    Li, Tao; Li, Xuejie; Sun, Guihua; Zhou, Yang; Chen, Fang; Zhong, Hexian; Yang, Chupeng; Luo, Weidong; Yao, Yongjian

    2015-09-15

    The distribution patterns of foraminiferal assemblages in relation to trace metals, sediment grain size, and calcium carbonate were studied in 232 surface sediments collected from the northwestern Taiwan Strait. Multivariate analyses of biotic and abiotic data revealed a separation of near-shore, coastal, and deep-water zones. The modified degree of contamination suggested that the overall contamination was very low to low. Trace metals were enriched in the near-shore and outside bays. Their distribution was likely determined by sediment transport pathways and hydrodynamic conditions. High metal concentrations co-occurred with a low density and diversity of foraminiferal assemblages. Pb, Ba, organic carbon, Ga, Zn, Cu, and Co had a positive correlation with near-shore assemblage, whereas Cr and Ni positively related to the deep-water assemblages. Some calcareous foraminifera were favored by CaCO3, Sr, and sand. This study highlights species' responses that are specific to environmental variables. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Calcification of the planktonic foraminifera Globigerina bulloides and carbonate ion concentration: Results from the Santa Barbara Basin

    Science.gov (United States)

    Osborne, Emily B.; Thunell, Robert C.; Marshall, Brittney J.; Holm, Jessica A.; Tappa, Eric J.; Benitez-Nelson, Claudia; Cai, Wei-Jun; Chen, Baoshan

    2016-08-01

    Planktonic foraminiferal calcification intensity, reflected by shell wall thickness, has been hypothesized to covary with the carbonate chemistry of seawater. Here we use both sediment trap and box core samples from the Santa Barbara Basin to evaluate the relationship between the calcification intensity of the planktonic foraminifera species Globigerina bulloides, measured by area density (µg/µm2), and the carbonate ion concentration of seawater ([CO32-]). We also evaluate the influence of both temperature and nutrient concentration ([PO43-]) on foraminiferal calcification and growth. The presence of two G. bulloides morphospecies with systematically different calcification properties and offset stable isotopic compositions was identified within sampling populations using distinguishing morphometric characteristics. The calcification temperature and by extension calcification depth of the more abundant "normal" G. bulloides morphospecies was determined using δ18O temperature estimates. Calcification depths vary seasonally with upwelling and were used to select the appropriate [CO32-], temperature, and [PO43-] depth measurements for comparison with area density. Seasonal upwelling in the study region also results in collinearity between independent variables complicating a straightforward statistical analysis. To address this issue, we use additional statistical diagnostics and a down core record to disentangle the respective roles of each parameter on G. bulloides calcification. Our results indicate that [CO32-] is the primary variable controlling calcification intensity while temperature influences shell size. We report a modern calibration for the normal G. bulloides morphospecies that can be used in down core studies of well-preserved sediments to estimate past [CO32-].

  3. One-year survey of a single Micronesian reef reveals extraordinarily rich diversity of Symbiodinium types in soritid foraminifera

    Science.gov (United States)

    Pochon, X.; Garcia-Cuetos, L.; Baker, A. C.; Castella, E.; Pawlowski, J.

    2007-12-01

    Recent molecular studies of symbiotic dinoflagellates (genus Symbiodinium) from a wide array of invertebrate hosts have revealed exceptional fine-scale symbiont diversity whose distribution among hosts, regions and environments exhibits significant biogeographic, ecological and evolutionary patterns. Here, similar molecular approaches using the internal transcribed spacer-2 (ITS-2) region were applied to investigate cryptic diversity in Symbiodinium inhabiting soritid foraminifera. Approximately 1,000 soritid specimens were collected and examined during a 12-month period over a 40 m depth gradient from a single reef in Guam, Micronesia. Out of 61 ITS-2 types distinguished, 46 were novel. Most types found are specific for soritid hosts, except for three types (C1, C15 and C19) that are common in metazoan hosts. The distribution of these symbionts was compared with the phylotype of their foraminiferal hosts, based on soritid small subunit ribosomal DNA sequences, and three new phylotypes of soritid hosts were identified based on these sequences. Phylogenetic analyses of 645 host-symbiont pairings revealed that most Symbiodinium types associated specifically with a particular foraminiferal host genus or species, and that the genetic diversity of these symbiont types was positively correlated with the genetic diversity found within each of the three host genera. Compared to previous molecular studies of Symbiodinium from other locations worldwide, the diversity reported here is exceptional and suggests that Micronesian coral reefs are home to a remarkably large Symbiodinium assemblage.

  4. New evidence on the origin of non-spinose pitted-cancellate species of the early Danian planktonic foraminifera

    Science.gov (United States)

    Arenillas, Ignacio; Arz, Jose Antonio

    2013-06-01

    Intermediate forms identified in some of the most continuous lower Danian sections allow a better understanding of the origin and evolution of pitted (Globanomalina) and cancellate (Praemurica) planktonic foraminifera. Both Globanomalina and Praemurica are part of a major Paleocene lineage, namely the "non-spinose lineage", which started to diverge in the early Danian. Transitional specimens strongly suggest the evolution from Parvularugoglobigerina to Globanomalina, and then to Praemurica. These evolutionary turnovers were quite rapid (probably lasting less than 10 kyr), and seem to have begun in the time equivalent of the lower part of the E. simplicissima Subzone, namely the middle part of the standard Zone Pa. The initial evolutionary trends within this non-spinose lineage were the increase of test size and lip thickness, and the evolution from tiny pore-murals to large pore-pits, and from smooth to pitted and finally cancellate walls. Biostratigraphic data suggest that evolution of the wall texture preceded the morphological evolution within each genus. The oldest species of both Globanomalina and Praemurica, namely G. archeocompressa and Pr. taurica, initially retained the external morphology of the ancestral Parvularugoglobigerina eugubina. Since their divergence, Globanomalina and Praemurica followed a separate evolutionary path, evolving into morphologically different species.

  5. Foraminifera from the Norian–Rhaetian reef carbonates of the Taurus Mountains (Saklıkent, Turkey

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    Senowbari-Daryan Baba

    2017-08-01

    Full Text Available Norian–Rhaetian reef carbonates are exposed in several localities in Taurus Mountains. They predominately contain hypercalcified sponges, followed by scleractinian corals and other less numerous organisms. A coherent Norian–Rhaetian reef structure is exposed near the small town of Saklıkent, west of Antalya. Foraminifers occur in reef carbonates of Saklıkent by numerous genera as shown in this paper. Two species — Siculocosta taurica and Siculocosta sadati — are described as new. The foraminiferal association of Saklıkent is similar or almost identical to the associations known from the Norian–Rhaetian reefs of Sicily, Northern Calcareous Alps, and Greece but shows less similarity to the foraminiferal association from the Apennines, Italy. The most abundant foraminifers are milioliporoids, particularly galeanellids and cucurbitids. Some sessile and agglutinated foraminifers, including Alpinophragmium perforatum Flügel, which mostly occurs abundantly in the Norian–Rhaetian reef carbonates, could not be found in the Saklıkent reef. This association of foraminifera is reported for the first time from a Norian–Rhaetian reef in the Taurus Mountains of Turkey.

  6. Phylogeography of the tropical planktonic foraminifera lineage globigerinella reveals isolation inconsistent with passive dispersal by ocean currents.

    Directory of Open Access Journals (Sweden)

    Agnes K M Weiner

    Full Text Available Morphologically defined species of marine plankton often harbor a considerable level of cryptic diversity. Since many morphospecies show cosmopolitan distribution, an understanding of biogeographic and evolutionary processes at the level of genetic diversity requires global sampling. We use a database of 387 single-specimen sequences of the SSU rDNA of the planktonic foraminifera Globigerinella as a model to assess the biogeographic and phylogenetic distributions of cryptic diversity in marine microplankton on a global scale. Our data confirm the existence of multiple, well isolated genetic lineages. An analysis of their abundance and distribution indicates that our sampling is likely to approximate the actual total diversity. Unexpectedly, we observe an uneven allocation of cryptic diversity among the phylogenetic lineages. We show that this pattern is neither an artifact of sampling intensity nor a function of lineage age. Instead, we argue that it reflects an ongoing speciation process in one of the three major lineages. Surprisingly, four of the six genetic types in the hyperdiverse lineage are biogeographically restricted to the Indopacific. Their mutual co-occurrence and their hierarchical phylogenetic structure provide no evidence for an origin through sudden habitat fragmentation and their limitation to the Indopacific challenges the view of a global gene flow within the warm-water provinces. This phenomenon shows that passive dispersal is not sufficient to describe the distribution of plankton diversity. Rather, these organisms show differentiated distribution patterns shaped by species interactions and reflecting phylogenetic contingency with unique histories of diversification rates.

  7. Preliminary results in larger benthic foraminifera assemblage in a mixed siliciclastic-carbonate platform from the Upper Cretaceous of the External Prebetic Domain (Valencia province, SE Spain)

    Science.gov (United States)

    Robles-Salcedo, Raquel; Vicedo, Vicent

    2016-04-01

    In the External Prebetic Domain (Betic Mountain Range, Valencia province, SE Spain) it is difficult to find good outcrops to study larger benthic foraminifera (LBF), particularly in the Upper Cretaceous deposits, because of three main reasons. During the Upper Cretaceous, the complex paleogeography in the northern Prebetic Domain developed a complex system of shallow-water platforms. This is directly linked to the complexity in the distribution of the facies observed nowadays, which may change drastically in lateral, closely related outcrops having a special negative impact in the lateral extension of stratigraphical levels containing LBF. The second reason is the nature of the shallow water environments in which the larger foraminifera lived. The local continental influence derived in the establishment of very complex mixed platforms. Thus, there is not a complete register through carbonate rocks, but an alternation of microconglomerates, sandstones, calcarenites and carbonates that can be observed in the stratigraphic series of the Upper Cretaceous. This affects negatively in observing changes in the evolutionary trends of taxa. The third reason difficulting the study of LBF in northern localities of the Prebetic Domain is diagenetic. Dolomitization affects a huge part of the Mesozoic rocks deleting all fossil microfauna in the affected rocks. Such three reasons are behind the difficulty in developing correlations and having a comprehensive understanding of the biostratigraphy and phylogeny of the taxa involved. However, after several field trips developed in the northern Prebetic area, an excellent reference section for the study of the LBF in the Prebetic Domain has been identified in the surroundings of the Pinet village (Valencia province). Here, a relatively continuous section with scarce dolomitization and good conditions of accessibility exists. The larger foraminifera assemblages appering in the Pinet section will be compared with other paleobiogeographic

  8. Fossil and Genetic Evidence for the Polyphyletic Nature of the Planktonic Foraminifera "Globigerinoides", and Description of the New Genus Trilobatus

    Science.gov (United States)

    Spezzaferri, Silvia; Kucera, Michal; Pearson, Paul Nicholas; Wade, Bridget Susan; Rappo, Sacha; Poole, Christopher Robert; Morard, Raphaël; Stalder, Claudio

    2015-01-01

    Planktonic foraminifera are one of the most abundant and diverse protists in the oceans. Their utility as paleo proxies requires rigorous taxonomy and comparison with living and genetically related counterparts. We merge genetic and fossil evidence of “Globigerinoides”, characterized by supplementary apertures on spiral side, in a new approach to trace their “total evidence phylogeny” since their first appearance in the latest Paleogene. Combined fossil and molecular genetic data indicate that this genus, as traditionally understood, is polyphyletic. Both datasets indicate the existence of two distinct lineages that evolved independently. One group includes “Globigerinoides” trilobus and its descendants, the extant “Globigerinoides” sacculifer, Orbulina universa and Sphaeroidinella dehiscens. The second group includes the Globigerinoides ruber clade with the extant G. conglobatus and G. elongatus and ancestors. In molecular phylogenies, the trilobus group is not the sister taxon of the ruber group. The ruber group clusters consistently together with the modern Globoturborotalita rubescens as a sister taxon. The re-analysis of the fossil record indicates that the first “Globigerinoides” in the late Oligocene are ancestral to the trilobus group, whereas the ruber group first appeared at the base of the Miocene with representatives distinct from the trilobus group. Therefore, polyphyly of the genus "Globigerinoides" as currently defined can only be avoided either by broadening the genus concept to include G. rubescens and a large number of fossil species without supplementary apertures, or if the trilobus group is assigned to a separate genus. Since the former is not feasible due to the lack of a clear diagnosis for such a broad genus, we erect a new genus Trilobatus for the trilobus group (type species Globigerina triloba Reuss) and amend Globoturborotalita and Globigerinoides to clarify morphology and wall textures of these genera. In the new

  9. Community benthic paleoecology from high-resolution climate records: Mollusca and foraminifera in post-glacial environments of the California margin

    Science.gov (United States)

    Myhre, Sarah E.; Kroeker, Kristy J.; Hill, Tessa M.; Roopnarine, Peter; Kennett, James P.

    2017-01-01

    Paleoecological reconstructions of past climate are often based on a single taxonomic group with a consistent presence. Less is known about the relationship between multi-taxon community-wide change and climate variability. Here we reconstruct paleoecological change in a Late Quaternary (16.1-3.4 ka) sediment core from the California margin (418 m below sea level) of Santa Barbara Basin (SBB), USA, using Mollusca (Animalia) and Foraminifera (Rhizaria) microfossils. Building upon previous investigations, we use multivariate ordination and cluster analyses to interpret community-scale changes in these distinctly different taxonomic groups across discrete climate episodes. The strongest differences between seafloor biological communities occurred between glacial (prior to Termination IA, 14.7 ka) and interglacial climate episodes. Holocene communities were well partitioned, indicating that sub-millennial oceanographic variability was recorded by these microfossils. We document strong evidence of chemosynthetic trophic webs and sulfidic environments (from gastropod Alia permodesta and bivalve Lucinoma aequizonata), which characterized restricted intervals previously interpreted as well oxygenated (such as the Pre-Bølling Warming). Mollusc records indicate first-order trophic energetic shifts between detrital and chemosynthetically-fixed carbon. Molluscs associated with widely different physiological preferences occur here within single, decadal intervals of sediment, and as such mollusc assemblages may reflect significant inter-decadal oceanographic variability. Foraminifera assemblages provide exceptional records of the sequential, chronological progression of the deglacial climatic and oceanographic events, whereas mollusc assemblages reflect non-chronological similarities in reoccurring communities. Foraminifera taxa that drive community similarity here are also independently recognized as marker species for seafloor hypoxia regimes, which provides support for the

  10. Delayed recolonization of foraminifera in a suddenly flooded tidal (former freshwater) marsh in Oregon (USA): Implications for relative sea-level reconstructions

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin P.; Khan, Nicole S.; Nelson, Alan R.; Witter, Robert C.; Engelhart, Simon E.; Ewald, Michael; Brophy, Laura; Bridgeland, William T.

    2016-04-01

    Stratigraphic sequences beneath salt marshes along the U.S. Pacific Northwest coast preserve 7000 years of plate-boundary earthquakes at the Cascadia subduction zone. The sequences record rapid rises in relative sea level during regional coseismic subsidence caused by great earthquakes and gradual falls in relative sea level during interseismic uplift between earthquakes. These relative sea-level changes are commonly quantified using foraminiferal transfer functions with the assumption that foraminifera rapidly recolonize salt marshes and adjacent tidal flats following coseismic subsidence. The restoration of tidal inundation in the Ni-les'tun unit (NM unit) of the Bandon Marsh National Wildlife Refuge (Oregon), following extensive dike removal in August 2011, allowed us to directly observe changes in foraminiferal assemblages that occur during rapid "coseismic" (simulated by dike removal with sudden tidal flooding) and "interseismic" (stabilization of the marsh following flooding) relative sea-level changes analogous to those of past earthquake cycles. We analyzed surface sediment samples from 10 tidal stations at the restoration site (NM unit) from mudflat to high marsh, and 10 unflooded stations in the Bandon Marsh control site. Samples were collected shortly before and at 1- to 6-month intervals for 3 years after tidal restoration of the NM unit. Although tide gauge and grain-size data show rapid restoration of tides during approximately the first 3 months after dike removal, recolonization of the NM unit by foraminifera was delayed at least 10 months. Re-establishment of typical tidal foraminiferal assemblages, as observed at the control site, required 31 months after tidal restoration, with Miliammina fusca being the dominant pioneering species. If typical of past recolonizations, this delayed foraminiferal recolonization affects the accuracy of coseismic subsidence estimates during past earthquakes because significant postseismic uplift may shortly follow

  11. Organic matter from benthic foraminifera (Ammonia beccarii) shells by FT-IR spectroscopy: A study on Tupilipalem, South east coast of India.

    Science.gov (United States)

    Sreenivasulu, G; Jayaraju, N; Sundara Raja Reddy, B C; Lakshmi Prasad, T; Nagalakshmi, K; Lakshmanna, B

    2017-01-01

    Fourier Transform Infrared Spectroscopy (FTIR) was used to study the variations in organic matters of benthic foraminifera (Ammonia beccarii) from four samples collected from beach environments from brackish environments along Tupilipalem coast (South east coast of India). Common absorption bands were observed as peaks in the range of 3600-3400 cm(-1), 3000-2850 cm(-1), 1750-1740 cm(-1), 1640-1600 cm(-1), 1450-1350 cm(-1), 885-870 cm(-1) and 725-675 cm(-1) in all the shells of Ammonia beccarii. The FTIR spectrum of station-1 represents the presence of alkanes (CH3) and alkyl halide (C-F stretching) with absorptions at the range 1385-1255 and 1350-1150 cm(-1) were observed and ether (C-O stretching) absorption band was observed at stations 1 and 3 with wavenumber of 1115 cm(-1) and 1117 cm(-1) respectively. Alkynes C-H bend was observed at station-1 with the wavenumber of 667.43 cm(-1). The shifting of peak positions in all the samples is could be due to presence of organic matter in the samples. Satellite remote sensing and field observation data revealed that the river mouth at Tupilipalem coast was closed by a sand bar. Consequentially, this waterbody may affect the species diversity. •Positions of the sampling locations were identified using a hand-held Garmin Global Positioning System (GPS).•Foraminifera from the sediment were obtained using a mixture of Bromoform and Acetone.•The functional groups present in the benthic foraminifera shells were recorded in the spectral range of 4000-400 cm(-1) using an FT-IR Spectrophotometer.

  12. Inorganic and stable isotope geochemistry of tropical Atlantic/Caribbean planktonic foraminifera : implications for the reconstruction of upper ocean temperatures and stratification

    OpenAIRE

    Regenberg, Marcus

    2007-01-01

    Planktonic foraminifera from tropical Atlantic and Caribbean sediment-surface samples (0-1 cm) show general westward-directed increasing calcification depths depending on the east-west increase in thermocline depth. Positively related planktonic foraminiferal Mg/Ca and carbonate ion concentration in the Caribbean show well preserved Mg/Ca down to depths about 1.5 km above the lysocline, which equals a carbonate ion concentration of 26-18 µmol/kg. Species-specific calibrations of Mg/Ca with d1...

  13. Using the Multiple Analysis Approach to Reconstruct Phylogenetic Relationships among Planktonic Foraminifera from Highly Divergent and Length-polymorphic SSU rDNA Sequences

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    Ralf Aurahs

    2009-11-01

    Full Text Available The high sequence divergence within the small subunit ribosomal RNA gene (SSU rDNA of foraminifera makes it difficult to establish the homology of individual nucleotides across taxa. Alignment-based approaches so far relied on time-consuming manual alignments and discarded up to 50% of the sequenced nucleotides prior to phylogenetic inference. Here, we investigate the potential of the multiple analysis approach to infer a molecular phylogeny of all modern planktonic foraminiferal taxa by using a matrix of 146 new and 153 previously published SSU rDNA sequences. Our multiple analysis approach is based on eleven different automated alignments, analysed separately under the maximum likelihood criterion. The high degree of congruence between the phylogenies derived from our novel approach, traditional manually homologized culled alignments and the fossil record indicates that poorly resolved nucleotide homology does not represent the most significant obstacle when exploring the phylogenetic structure of the SSU rDNA in planktonic foraminifera. We show that approaches designed to extract phylogenetically valuable signals from complete sequences show more promise to resolve the backbone of the planktonic foraminifer tree than attempts to establish strictly homologous base calls in a manual alignment.

  14. Environmental variations in a semi-enclosed embayment (Amvrakikos Gulf, Greece – reconstructions based on benthic foraminifera abundance and lipid biomarker pattern

    Directory of Open Access Journals (Sweden)

    E. Kaberi

    2012-06-01

    Full Text Available The evolution of environmental changes during the last decades and the impact on the living biomass in the western part of Amvrakikos Gulf was investigated using abundances of benthic foraminifera and lipid biomarker concentrations. These proxies indicated that the gulf has dramatically changed due to eutrophication. Eutrophication has led to a higher productivity, a higher bacterial biomass, shifts towards opportunistic and tolerant benthic foraminifera species (e.g. B. elongata, N. turgida, T. agglutinans, A. tepida and a lower benthic species density. Close to the Preveza Straits (connection between the gulf and the Ionian Sea, the benthic assemblages appeared to be less productive and more diversified under more oxygenated conditions. Sea grass meadows largely contributed to the organic matter at this sampling site. Isorenieratane, chlorobactane and lycopane together with oxygen monitoring data indicated that anoxic (and partly euxinic conditions prevailed seasonally throughout the western part of the gulf with more severe hypoxia towards the east. Increased surface water temperatures have led to a higher stratification, which reduced oxygen resupply to bottom waters. These developments are reasons for mass mortality events and ecosystem decline observed in Amvrakikos Gulf.

  15. South Equatorial Current (SEC) driven changes at DSDP Site 237, Central Indian Ocean, during the Plio-Pleistocene: Evidence from Benthic Foraminifera and Stable Isotopes

    Science.gov (United States)

    Gupta, Anil K.; Das, Moumita; Bhaskar, K.

    2006-12-01

    This study attempts to analyse paleoceanographic changes in the Central Indian Ocean (Deep Sea Drilling Project Site 237), linked to monsoon variability as well as deep-sea circulation during the Plio-Pleistocene. We used factor and cluster analyses of census data of the 34 most dominant species of benthic foraminifera that enabled us to identify five biofacies: Astrononion umbilicatulum- Uvigerina proboscidea (Au-Up), Pullenia bulloides- Bulimina striata (Pb-Bs), Globocassidulina tumida- Nuttallides umbonifera (Gt-Nu), Gyroidinoides nitidula- Cibicides wuellerstorfi (Gn-Cw) and Cassidulina carinata- Cassidulina laevigata (Cc-Cl) biofacies. Knowledge of the environmental preferences of modern deep-sea benthic foraminifera helped to interpret the results of factor and cluster analyses in combination with oxygen and carbon isotope values. The biofacies indicative of high surface productivity, resulting from a stronger South Equatorial Current (Au-Up and Pb-Bs biofacies), dominate the early Pliocene interval (5.6-4.5 Ma) of global warmth. An intense Indo-Pacific 'biogenic bloom' and strong Oxygen Minimum Zone extended to intermediate depths (˜1000-2000 m) over large parts of the Indian Ocean in the early Pliocene. Since 4.5 Ma, the food supply in the Central Indian Ocean dropped and fluctuated while deep waters were corrosive (biofacies Gt-Nu, Gn-Cw). The Pleistocene interval is characterized by an intermediate flux of organic matter (Cc-Cl biofacies).

  16. Determination of trace element incorporation into tests of in vitro grown foraminifera by micro- SYXRF - a basis for the development of paleoproxies

    Science.gov (United States)

    Kramar, U.; Munsel, D.; Berner, Z.; Bijma, J.; Nehrke, G.

    2009-04-01

    Trace element chemistry and isotopic composition of calcareous foraminiferal tests reflect the environment in which they grow. Consequently, geochemical parameters of the tests are often used as paleo-proxies to constrain the environmental conditions in ancient seas (e.g. Boyle, 1981). Currently only a limited number of trace elements is used as proxies. Difficulties arise from the fact that often a proxy depends on several parameters and that seawater-chemistry may be influenced by local sources such as hydrothermalism or by changes in redox conditions. Reliable experimental data on elements which can be considered as diagnostic for hydrothermal activity and/or changing redox conditions are non-existent to scarce. We have cultured shallow benthic foraminifera (Ammonia tepida) under controlled conditions at defined trace element levels (5, 10, 20-fold average seawater concentration) representing two distinct environmental simulations, one for hydrothermal (Mn, Cu, Co, Ni) and another for changing redox conditions (Mo, As, Cr, and V). The goal of our investigations is to provide diagenetically unbiased experimental trace element data in foraminiferal shells as a basis for a more complete understanding of trace element partition between seawater and foraminifera shell calcite as a function of environmental conditions. The foraminifers did not reproduce in culture but grew new chambers as evidenced by labelling with calcein (Bernhard et al., 2004). The trace element uptake into old (field grown) and new chambers was subsequently analysed. Using excitation energies of 12.5 keV and focusing by refractive lenses to a spot size of 2x5 m at FLUO-beamline of ANKA and 25 keV and confocal poly capillary optics at HASYLAB Beamline L, old chambers and new ones of the same foraminifera have been analyzed separately for Ni, Cu, Zn, Mn, As, Cr, V, Sr and Mo. The data will be compared with results from LA-ICP/MS analytics. Concentrations of the elements of interest in the newly

  17. Stable carbon isotope gradients in benthic foraminifera as proxy for organic carbon fluxes in the Mediterranean Sea

    Science.gov (United States)

    Theodor, Marc; Schmiedl, Gerhard; Jorissen, Frans; Mackensen, Andreas

    2016-11-01

    We have determined stable carbon isotope ratios of epifaunal and shallow infaunal benthic foraminifera in the Mediterranean Sea to relate the inferred gradient of pore water δ13CDIC to varying trophic conditions. This is a prerequisite for developing this difference into a potential transfer function for organic matter flux rates. The data set is based on samples retrieved from a well-defined bathymetric range (400-1500 m water depth) of sub-basins in the western, central, and eastern Mediterranean Sea. Regional contrasts in organic matter fluxes and associated δ13CDIC of pore water are recorded by the δ13C difference (Δδ13CUmed-Epi) between the shallow infaunal Uvigerina mediterranea and epifaunal species (Planulina ariminensis, Cibicidoides pachydermus, Cibicides lobatulus). Within epifaunal taxa, the highest δ13C values are recorded for P. ariminensis, providing the best indicator for bottom water δ13CDIC. In contrast, C. pachydermus reveals minor pore water effects at the more eutrophic sites. Because of ontogenetic trends in the δ13C signal of U. mediterranea of up to 1.04 ‰, only tests larger than 600 µm were used for the development of the transfer function. The recorded differences in the δ13C values of U. mediterranea and epifaunal taxa (Δδ13CUmed-Epi) range from -0.46 to -2.13 ‰, with generally higher offsets at more eutrophic sites. The measured δ13C differences are related to site-specific differences in microhabitat, depth of the principal sedimentary redox boundary, and TOC content of the ambient sediment. The Δδ13CUmed-Epi values reveal a consistent relation to Corg fluxes estimated from satellite-derived surface water primary production in open-marine settings of the Alboran Sea, Mallorca Channel, Strait of Sicily, and southern Aegean Sea. In contrast, Δδ13CUmed-Epi values in areas affected by intense resuspension and riverine organic matter sources of the northern to central Aegean Sea and the canyon systems of the Gulf of Lion

  18. SIMMAX: A modern analog technique to deduce Atlantic sea surface temperatures from planktonic foraminifera in deep-sea sediments

    Science.gov (United States)

    Pflaumann, Uwe; Duprat, Josette; Pujol, Claude; Labeyrie, Laurent D.

    1996-02-01

    leave the system.) (Paper 95PA01743,SIMMAX: A modern analog technique to deduce Atlantic sea surfacetemperatures from planktonic foraminifera in deep-sea sediments, UwePflaumann, Josette Duprat, Claude Pujol, and Laurent D. Labeyrie).Diskette may be ordered from American Geophysical Union, 2000Florida Avenue, N.W., Washington, DC 20009; Payment mustaccompany order.

  19. Planktonic Foraminifera as Sensitive Recorders of Climate Variability in the Eastern Mediterranean During the Last ~90 ka

    Science.gov (United States)

    Almogi-Labin, A.; Bar-Matthews, M.; Ayalon, A.; Paterne, M.

    2014-12-01

    Planktonic foraminifera (PF) are widely used in Quaternary paleoceanography as carriers of oxygen stable isotope signal. This signal is one of the main tools for establishing chronostratigraphy and determining the nature of global and local glacial and interglacial cycles. In this study, the focus is on the PF assemblages which are sensitive recorders of climate and water column properties including the degree of water column stratification and trophic levels. In order to reconstruct the climate variability of the last ~90 ka, core MDVAL9501 (980 m water depth), taken by R/V Marion Dufresnae, SE of Cyprus, was studied. A δ18O-Globigerinoides ruber stratigraphy was established and correlated with well-dated (U/Th) speleothem records of Soreq Cave and radiocarbon dates. The sedimentary record in this core covers the last ~90ka. Variations in PF assemblage composition indicate that conditions shifted between two main climatic scenarios. During the last glacial cooler, more aerated, less stratified and more mesotrophic water column persisted with distinct seasonality. This is evident from the occurrence of two deep water dwellers Globorotalia inflata being abundant from 75 to 50 ka BP and G. scitula from 55 to 15 ka BP (with respective SST of 15-16 ºC and 11-13 ºC) and accompanied continuously by the cold water species Neogloboqudrina pachyderma and Globigerina bulloides. Among the "warm" water species G. ruber is nearly the only "survivor" during the glacial period comprising 25-50% of the assemblage with lower values corresponding to minima in D-O events. During Holocene, water column was warmer, more stratified, mostly oligotrophic with reduced seasonality. The dominating species were G. ruber and other "warm" water species comprising >75% of the assemblage and occurring in low numbers. An exception are sapropel S1 (early Holocene) and S3 (MIS 5.1) periods, when lower δ18O and highest TOC values prevail with significantly increased numerical abundance of PF

  20. Holocene Climatic and Hydrologic Variability as Recorded in the Benthic Foraminifera Ammonia Beccarii From Tampa Bay, Florida

    Science.gov (United States)

    Hoover, K. J.; Hastings, D. W.; Flower, B. P.; Cronin, T. M.; Brooks, G. R.

    2008-12-01

    The objective of this study is to reconstruct the climate history of Tampa Bay, Florida over the Holocene epoch using the benthic foraminifera Ammonia beccarii from five sediment cores. Here we present a reconstruction based on oxygen isotopic ratios and Mg/Ca data that provides critical information on the history of climate changes in southwest Florida. Oxygen isotopes and Mg/Ca data from samples of A. beccarii taken from a series of five sediment cores provide records of temperature and salinity changes in Tampa Bay over the last 10,000 years. Sample age was constrained using a total of 21 AMS radiocarbon dates, 11 measured on A. beccarii and 10 measured on other material in the sediment (shell, bulk organic sediment, mollusk, organic sediment, and plant). The temperature reconstruction we present provides evidence of significant variability in the climate of Tampa Bay throughout the Holocene epoch, as indicated by a relative temperature range of 6° C. The highest reconstructed temperatures within this record are found from 1000-700 yr BP, which correlates with the commonly accepted timing of the Medieval Warm Period. The lowest temperatures reflected in this record occur from 500-150 yr BP, correlating with the timing of the Little Ice Age. This record also shows that relative temperatures have increased by approximately 3-4° C from 500 yr BP to present. The signal for δ18Osw was determined from δ18Ocalcite and relative temperatures reconstructed from Mg/Ca; changes in both δ18Osw and temperature are relative since the temperature calibration is not species specific. The results would be improved if a Mg/Ca temperature calibration for the species A. beccarii was developed and used. Values of δ18Osw fall within a range of 2.0 permil VPDB over the last 10,000 years, indicating significant changes to the hydrology of Tampa Bay. These results support evidence from the Gulf of Mexico for substantial hydrologic variability on the sub-centennial-scale. These

  1. Dinoflagellate cysts and benthic foraminifera in surface sediments from the Mar Piccolo in Taranto (Ionian Sea, Southern Italy)

    Science.gov (United States)

    Ferraro, L.; Rubino, F.; Frontalini, F.; Belmonte, M.; Di Leo, A.; Giandomenico, S.; Greco, M.; Lirer, F.; Spada, L.; Vallefuoco, M.

    2012-12-01

    Coastal areas have traditionally been places of human settlement, with the increasing development of cities, industries and other human-related activities possibly having an impact on the aquatic ecosystem. These impacts may take the form of pollution from industrial, domestic, agricultural or mining activities. For this reason, attention to marine environmental problems has recently increased and the search for new methodologies and techniques for the monitoring of coastal-marine areas become more and more active and accurate. In this context biological indicators result a useful tool to provide indication of environmental conditions including the presence or absence of contaminants; in fact biological monitoring is more directly related to the ecological health of an ecosystem than are chemical data. The increasing importance of bioindicators is also encouraged within the European Union's Water Framework Directive (WFD), which aims to achieve a good ecological status in all European water bodies (i.e., rivers, lakes and coastal waters). Among the wide range of bioindicators, 5 biological elements are listed within the WFD: phytoplankton, macroalgae, angiosperms, benthic invertebrates and fishes. Benthic invertebrates as foraminifera represent a group of protozoa widely distributed in all brackish and marine environments which are used in studies assessing the environmental quality of areas subject to intense human activity. Moreover in coastal marine environments benthic and pelagic domain present several relationships, one of these is represented by the life cycles of phytoplankton species, as Dinoflagellates, which include the production of benthic stages (cysts). These dormant stages, which accumulate in confined marine muddy areas, such as ports, lagoons or estuaries, can reach high densities, similar to the seed banks of terrestrial plants. The cysts have a high preservation potential and can rest in/on the sediments for decades. Due to this peculiar

  2. New insights to ecology, ontogeny and teratology of Larger Benthic Foraminifera by biometrics based on microCT.

    Science.gov (United States)

    Briguglio, A.; Fabienke, W.; Wolfgring, E.; Ferrández Cañadell, C.; Hohenegger, J.

    2012-04-01

    The main function of tests in Larger Benthic Foraminifera (LBF) is to provide their endosymbiotic algae with enough light to obtain net photosynthetic rates and to create sufficient accommodation space. To study the relation between these two factors and to understand how the cell reacts to growth and to the environment, the newly developed technique of X-ray micro-Computer-Tomography (microCT) allows measurement of all characters of complex tests without destruction. Growth studies on 48 specimens of living and fossil species have been performed. The volumes of the lumina have been calculated as well as further 2-dimensional parameters related to volumes as chamber height, chamber width and septal distance. The volumes of chamber lumina represent cell growth in their sequence, thus demonstrating interruptions, increase/decrease or oscillations in growth rates caused by external factors affecting growth during life time (e.g. seasons). Correlations between volumes and the one-dimensional parameters have been calculated to check the form of relationship. According to our results, some parameters seem to oscillate exactly as the volume (therefore accommodating it), while others seem to oscillate constantly around a given growth function. Concerning the palaeobiology, beside the study of specimens with 'normal' growth, thus not drastically affected by external factors, some interesting morphologies have been investigated. Pluriembryonal apparati as well as secondary equatorial layers have been segmented, extracted and quantified in almost 15 specimens of Cycloclypeus carpenteri, 8 twin specimens of nummulitids tests have been also investigated to show where and how the fusion starts and volumetric quantifications of each single spiral in multispiral grown test of some large Eocene Nummulitids has also been calculated to show in which way and when (ontogenetically) a new spiral starts. The combination of all measurements allows interpretation of different biological

  3. Reconstructing pre-impact baseline conditions using benthic foraminifera in an area of increasing petroleum exploration activities

    Science.gov (United States)

    Dijkstra, Noortje; Junttila, Juho; Aagaard-Sørensen, Steffen

    2016-04-01

    While macrofauna is traditionally used to bio-monitor to state of the ecosystem, benthic foraminifera have large potential for bio-monitoring as well. As their tests stay preserved in the sedimentary archive it is possible to reconstruct pre-impacted conditions, by studying foraminiferal assemblages in sediment cores. The use of foraminiferal faunas as bio-monitoring tools is complicated by the natural variability. Therefore, detailed site specific studies are needed, to understand the range of natural variability of the area of interest. This study characterizes the natural variability in the Bjørnøyrenna-Ingøydjupet area in the Southern Barents Sea. The Southern Barents Sea is a relatively un-impacted and uncontaminated area, however petroleum industry related activities are expected to increase in the near future. This makes the area a valuable natural laboratory to establish pre-impacted baselines for future seabed monitoring programs. Benthic foraminiferal assemblages were examined at high resolution in sediment cores and compared to sediment properties and metal concentrations. Species associated to temperate water masses dominate in the southern part of the study area, while species associated to cooler water masses increase in abundance towards the north into Bjørnøyrenna. Additionally, the foraminiferal assemblages might reflect climatic oscillations on both millennial and decadal time scales. Patterns in the calcareous foraminiferal assemblages suggest an enhanced food supply as a result of increased Atlantic Water inflow through the region during the last 150 years. Sediment TOC content has been linked with variable inflow of Atlantic Water. A strong positive correlation was observed between TOC content with metal content in the cores. It is therefore essential to consider the role of natural variability of oceanographic conditions when using benthic foraminiferal assemblages to monitor for potential anthropogenic impacts on the environment. This

  4. Evolution of planktonic foraminifera and thermocline in the southern South China Sea since 12 Ma (ODP-184, Site 1143)

    Institute of Scientific and Technical Information of China (English)

    Ll; Baohua

    2001-01-01

    ., High-resolution records of the thermocline in the Okinawa trough since about 10000 aBP,Science in China, Ser. D, 2001, 44(3): 193-200.[12]Shipboard Scientific Party, Site 1143, in Proceedings of the ODP, Initial Reports 184 (CD-ROM) (eds. Wang, P., Prell, W.L., Blum, P. et al.), Ocean Drilling Program, Texas A&M University, College Station, 2000, 1-103.[13]Le, J., Shackleton, N. J., Carbonate dissolution fluctuation in the western Equatorial Pacific during the late Quaternary,Paleoceanography, 1992, 7(1): 21-42.[14]Bolli, H. M., Saunders, J. B., Oligocene to Holocene lower latitude planktonic foraminifera, in Plankton Stratigraphy (eds.Bolli, H. M., Saunders, J. B., Perch-Nielsen, K.), Cambridge: Cambridge University Press, 1985, 155-262.[15]Kennett, J. P., Srinivasan, M. S., Neogene Planktonic Foraminifera: A Phylogenic Atlas, New York: Hutchinson Ross Pub lishing Company, 1983, 1-265.[16]Berggren, W. A., Kent, D. V., Swisher, C. C. et al., A revised Cenozoic geochronology and chronostratigraphy, in Geo chronology Time Scales and Global Stratigraphic Correlation (eds. Berggren, W. A., Kent, D. V., Aubry, M. P. et al.),SEMP Special Publication, 1995, 54: 129-212.[17]Thompson, P. R., Bé, A. W. H., Duplessy, J. C. et al., Disappearance of pink-pigmented Globigerinoides ruber at 120,000yr BP in the Indian and Pacific Oceans, Nature, 1979, 280: 554-558.[18]Li, B., Chen, M. P., Zhao, Q. et al., Planktonic foraminiferal events and their paleoceanographic signifances in the south ern South China Sea since the last 800,000 years, Acta Micropaleontoligia Sinica (in Chinese with English abstract), 2001, 18(1): 1-9.[19]Wang, P., Xia, L., Wang, L. et al., Lower boundary of the marine Pleistocene in the northern shelf of the South China Sea,Acta Geologica Sinica (in Chinese with English abstract), 1991, 2:176-187.[20]Zhao, Q., Jian, Z., Li, B. et al., Microtektites in the deep sea core of South China Sea at 780,000 ys B.P. and its signifi cance

  5. Impact of seawater pCO2 on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with Ammonia tepida

    NARCIS (Netherlands)

    Dissard, D.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2010-01-01

    Evidence of increasing concentrations of dissolved carbon dioxide, especially in the surface ocean and its associated impacts on calcifying organisms, is accumulating. Among these organisms, benthic and planktonic foraminifera are responsible for a large amount of the globally precipitated calcium c

  6. Neogene stratigraphy, foraminifera, diatoms, and depositional history of Maria Madre Island, Mexico: Evidence of early Neogene marine conditions in the southern Gulf of California

    Science.gov (United States)

    McCloy, C.; Ingle, J.C.; Barron, J.A.

    1988-01-01

    Foraminifera and diatoms have been analyzed from an upper Miocene through Pleistocene(?) sequence of marine sediments exposed on Maria Madre Island, largest of the Tre??s Marias Islands off the Pacific coast of Mexico. The Neogene stratigraphic sequence exposed on Maria Madre Island includes a mid-Miocene(?) non-marine and/or shallow marine sandstone unconformably overlain by a lower upper Miocene to uppermost Miocene upper to middle bathyal laminated and massive diatomite, mudstone, and siltstone unit. This unit is unconformably overlain by lower Pliocene middle to lower bathyal sandstones and siltstones which, in turn, are unconformably overlain by upper Pliocene through Pleistocene(?) upper bathyal to upper middle bathyal foraminiferal limestones and siltstones. These beds are unconformably capped by Pleistocene terrace deposits. Basement rocks on the island include Cretaceous granite and granodiorite, and Tertiary(?) andesites and rhyolites. The upper Miocene diatomaceous unit contains a low diversity foraminiferal fauna dominated by species of Bolivina indicating low oxygen conditions in the proto-Gulf Maria Madre basin. The diatomaceous unit grades into a mudstone that contains a latest Miocene upper to middle bathyal biofacies characterized by Baggina californica and Uvigerina hootsi along with displaced neritic taxa. An angular unconformity separates the upper Miocene middle bathyal sediments from overlying lower Pliocene siltstones and mudstones that contain a middle to lower bathyal biofacies and abundant planktonic species including Neogloboquadrina acostaensis and Pulleniatina primalis indicating an early Pliocene age. Significantly, this Pliocene unit contains common occurrences of benthic species restricted to Miocene sediments in California including Bulimina uvigerinaformis. Pliocene to Pleistocene(?) foraminiferal limestones and siltstones characterize submarine bank accumulations formed during uplift of the Tre??s Marias Island area, and include

  7. Illustration as a way to explain the complex structures of foraminifera. The scientific drawing of Lukas Hottinger. In memoriam (1933-2011)

    Science.gov (United States)

    Leria, M.; Ferrandez, C.; Ruiz-Ortega, M.

    2012-12-01

    Scientific illustration is a fundamental tool for transmitting scientific knowledge because it allows to define aspects that cannot be appreciated just by text description, or by means of photography. This study is based on the collection of illustrations created by the paleontologist Lukas Hottinger (1933-2011) during his extensive career. Hottinger studied, described and illustrated foraminifera for more than fifty years. The use of illustration is essential for studying, describing and clasifying these marine microfossils. Foraminifera are a constituent of marine sedimentary rocks; the study of their internal anatomy often is made from thin sections of rocks, a destructive technique which provides only two dimensional sections. The internal three-dimensional morphology of a species must be interpreted and reconstructed from numerous random two-dimensional sections. New technologies, such as SEM or more recently X-ray Microtomography provided progressively better images of the internal structure but this information, while useful, is still insufficient to explain with simplicity and efficacy what an illustration of a synthetic 3D model shows at a glance. This study is based on a review of 78 publications by Lukas Hottinger on foraminiferal inner structure. In addition, up to 150 illustrations by Hottinger were analyzed, as well as other works written by his colleagues during the same years (1956-2009). Hottinger's work includes several reference papers on the structure and systematics of different groups of larger foraminifera in which his three dimensional models play a fundamental role in synthesizing and making understandable the complexity of these shells. Illustrations of 3D models were particularly selected because of their conceptual complexity. They do not represent a view of the foraminiferal structure that can be observe directly, but a synthetic abstraction constructed from the observation and interpretation of many random two-dimensional sections of

  8. Calcification and growth processes in planktonic foraminifera complicate the use of B/Ca and U/Ca as carbonate chemistry proxies

    Science.gov (United States)

    Salmon, Kate H.; Anand, Pallavi; Sexton, Philip F.; Conte, Maureen

    2016-09-01

    Although boron and uranium to calcium ratios (B/Ca, U/Ca) in planktonic foraminifera have recently received much attention as potential proxies for ocean carbonate chemistry, the extent of a carbonate chemistry control on these ratios remains contentious. Here, we use bi-weekly sediment trap samples collected from the subtropical North Atlantic in combination with measured oceanographic data from the same location to evaluate the dominant oceanographic controls on B/Ca and U/Ca in three depth-stratified species of planktonic foraminifera. We also test the control of biological, growth-related, processes on planktonic foraminiferal B and U incorporation by using foraminifer test area density (μ g /μm2) (a monitor of test thickness) and test size from the same samples. B/Ca and U/Ca show little or no significant correlation with carbonate system parameters both within this study and in comparison with other published works. We provide the first evidence for a strong positive relationship between area density (test thickness) and B/Ca, and reveal that this is consistent in all species studied, suggesting a likely role for calcification in controlling boron partitioning into foraminiferal calcite. This finding is consistent with previous observations of less efficient discrimination against trace element 'impurities' (such as B), at higher calcification rates. We observe little or no dependency of B/Ca on test size. In marked contrast, we find that U/Ca displays a strong species-specific dependency on test size in all species, but no relationship with test thickness, implicating some other biological control (possibly related to growth), rather than a calcification control, on U incorporation into foraminiferal calcite. Our results caution against the use of B/Ca and U/Ca in planktonic foraminifera as reliable proxies for the ocean carbonate system and recommend that future work should concentrate on improving the mechanistic understanding of how planktonic

  9. Trace metal/Ca ratios in benthic foraminifera: the potential to reconstruct past variations in temperature and hypoxia in shelf regions

    Directory of Open Access Journals (Sweden)

    J. Groeneveld

    2013-03-01

    Full Text Available Shelf and coastal regions are exceptionally important for many countries as they provide the main habitat for many economically important fish and shellfish species. With ongoing global warming and human-induced eutrophication the shelf regions are especially affected, resulting in increased temperatures and stratification as well as oxygen depletion of the bottom waters. In order to be able to predict the magnitude of these changes in the future it is necessary to study how they varied in the past. Commonly used foraminiferal climate and environmental proxies, e.g. stable isotopes and trace metal/Ca ratios, which are applied in open-ocean settings are not necessarily applicable in shelf regions, either as faunas are completely different or as conditions change a-typical compared to the open-ocean. In this study we explore the use of Mg/Ca as paleothermometer and Mn/Ca as a potential proxy for changing dissolved oxygen conditions on the benthic foraminifera Bulimina marginata and Globobulimina turgida. Living specimens were collected from the Skagerrak and the Gullmar Fjord (SW-Sweden; the latter is hypoxic for several months a year. As the specimens were alive when collected it can be excluded that any diagenetic coatings have affected the trace metal/Ca ratios. The Mg/Ca ratios are similar to previously published values from the literature but display much larger variation than would be expected from the annual temperature change of less than 2 °C. An additional impact of the difference in the carbonate ion saturation state between the Skagerrak and the Gullmar Fjord could explain the results. Mn/Ca ratios on Globobulimina turgida potentially record variations in dissolved oxygen of the habitat where the foraminifera calcify. Samples from the Skagerrak display increased Mn/Ca in specimens which lived deeper in the sediment than those that lived near the surface. Globobulimina turgida samples from the lower oxygen Gullmar Fjord showed

  10. Mg/Ca and Mn/Ca ratios in benthic foraminifera: the potential to reconstruct past variations in temperature and hypoxia in shelf regions

    Directory of Open Access Journals (Sweden)

    J. Groeneveld

    2013-07-01

    Full Text Available Shelf and coastal regions are exceptionally important for many countries as they provide the main habitat for many economically important fish and shellfish species. With ongoing climate change and human-induced eutrophication the shelf regions are especially affected, resulting in increased temperatures and stratification as well as oxygen depletion of the bottom waters. In order to be able to predict the magnitude of these changes in the future, it is necessary to study how they varied in the past. Commonly used foraminiferal climate and environmental proxies, e.g., stable isotopes and trace metal/Ca ratios, that are applied in open-ocean settings are not necessarily applicable in shelf regions, either as faunas are significantly different or as conditions can change much faster compared to the open ocean. In this study we explore the use of Mg/Ca as paleothermometer and Mn/Ca as a potential proxy for changing dissolved oxygen conditions in bottom water on the benthic foraminifera Bulimina marginata and Globobulimina turgida. Living specimens were collected from the Skagerrak and the Gullmar Fjord (SW Sweden; the latter is hypoxic for several months a year. As the specimens were alive when collected, we assume it unlikely that any diagenetic coatings have already significantly affected the trace metal/Ca ratios. The Mg/Ca ratios are similar to previously published values but display much larger variation than would be expected from the annual temperature change of less than 2 °C. An additional impact of the difference in the calcite saturation state between the Skagerrak and the Gullmar Fjord could explain the results. Mn/Ca ratios from G. turgida can potentially be related to variations in dissolved oxygen of the habitat where the foraminifera calcify. Samples from the Skagerrak display increased Mn/Ca in specimens that lived deeper in the sediment than those that lived near the surface. G. turgida samples from the low-oxygen Gullmar Fjord

  11. Evaluation of automated flow-through time-resolved analysis of foraminifera for Mg/Ca paleothermometry

    Science.gov (United States)

    Klinkhammer, G. P.; Haley, B. A.; Mix, A. C.; Benway, H. M.; Cheseby, M.

    2004-12-01

    changes during ontogeny. We find that the most susceptible fraction of biogenic calcite in surface dwelling foraminifera gives the most accurate value for SST and therefore best represents primary calcite. Sequential dissolution curves can be used to correct the primary Mg/Ca ratio for clay, if necessary. However, the temporal separation of calcite from clay in FT-TRA is so complete that this correction is typically ≤2%, even in clay-rich sediments. Unlike hands-on batch methods, that are difficult to reproduce exactly, flow-through lends itself to automation, providing precise replication of treatment for every sample. Our automated flow-through system can process 22 samples, two system blanks, and 48 mixed standards in <12 hours of unattended operation. FT-TRA thus represents a faster, cheaper, and better way to determine Mg/Ca ratios in foraminiferal calcite.

  12. Bottom water production variability in the Ross Sea slope during the Late-Pleistocene-Holocene as revealed by benthic foraminifera and sediment geochemistry

    Science.gov (United States)

    Asioli, A.; Langone, L.; Tateo, F.; Giannossi, M. L.; Giglio, F.; Summa, V.; Piva, A.; Ridente, D.; Trincardi, F.

    2009-04-01

    The Antarctic area produces bottom waters that ventilate the vast majority of the deep basins in the rest of the world ocean. The rate of formation in the source area and the strength of these cold bottom waters affect their flow toward the equator and are key factors affecting the Global Thermohaline Circulation during modern and past climate conditions. We present the results of a multidisciplinary study carried out on a core collected in 2377m of water depth on the slope off the Drygalski Basin (Ross Sea), along the modern path of the bottom waters. The goal of this research is to detect a qualitative signal of possible changes in the rate of bottom water production during the Late Pleistocene-Holocene by integrating micropaleontological and geochemical proxies. The micropaleontological signal is represented by the quantitative and qualitative variations of the agglutinated benthic foraminifera assemblages, while the amount of TOC, nitrogen, δ13C, δ15N, biogenic silica, CaCO3 in the sediment, along with the bulk rock mineralogy, provide information on the paleoproductivity and allow reconstruction of changes in the paleocirculation. The chronology is supported by 14C AMS datings on organic matter. Although this study is still in progress, the results obtained allow the following observations: 1) the Holocene sequence includes a major turnover around 8-8.5 calib kyr BP, leading to reduced nutrient utilization, probably reflecting an increased nutrient supply induced by an enhanced Upper Circumpolar Deep Water upwelling; 2) within this general context, the total concentration of benthic foraminifera preserved in the fossil component records millennial scale cycles of variable amplitude after 8.5 calib kyr BP and to present time. This oscillatory trend is paralleled by other parameters, such as the magnetic susceptibility, the dry density, the sheet silicates and the δ15N; 3) minima in foraminifera concentration reflect relatively increased dissolution, weaker

  13. Benthic foraminifera living in Gulf of Mexico bathyal and abyssal sediments: Community analysis and comparison to metazoan meiofaunal biomass and density

    Science.gov (United States)

    Bernhard, Joan M.; Sen Gupta, Barun K.; Baguley, Jeffrey G.

    2008-12-01

    Benthic foraminiferal biomass, density, and species composition were determined at 10 sites in the Gulf of Mexico. During June 2001 and 2002, sediment samples were collected with a GoMex box corer. A 7.5-cm diameter subcore was taken from a box core collected at each site and sliced into 1-cm or 2-cm sections to a depth of 2 or 3 cm; the >63-μm fraction was examined shipboard for benthic foraminifera. Individual foraminifers were extracted for adenosine triphosphate (ATP) using a luciferin-luciferase assay, which indicated the total ATP content per specimen; that data was converted to organic carbon. Foraminiferal biomass and density varied substantially (˜2-53 mg C m -2; ˜3600-44,500 individuals m -2, respectively) and inconsistently with water depth: although two ˜1000-m deep sites were geographically separated by only ˜75 km, the foraminiferal biomass at one site was relatively low (˜9 mg C m -2) while the other site had the highest foraminiferal biomass (˜53 mg C m -2). Although most samples from Sigsbee Plain (>3000 m) had low biomass, one Sigsbee site had >20 mg foraminiferal C m -2. The foraminiferal community from all sites (i.e. bathyal and abyssal locales) was dominated by agglutinated, rather than calcareous or tectinous, species. Foraminiferal density never exceeded that of metazoan meiofauna at any site. Foraminiferal biomass, however, exceeded metazoan meiofaunal biomass at 5 of the 10 sites, indicating that foraminifera constitute a major component of the Gulf's deep-water meiofaunal biomass.

  14. Response of pteropods and foraminifera to changing pCO2 and pH in last 250,000 years

    Science.gov (United States)

    Hart, Malcolm; Wall-Palmer, Deborah; Smart, Christopher

    2010-05-01

    Over the last 250,000 years the diversity and quality of preservation of pteropods (holoplanktic gastropods) has fluctuated in response to glacial/interglacial cycles. This is almost certainly related to the change in oceanic pH as the best preservation is recorded in glacial cycles when pCO2 was at a lower level than during interglacials. Detailed studies of the pteropod assemblages from marine cores taken near Montserrat (Caribbean Sea) have provided a high resolution database with which to make comparisons world-wide. There are peaks of diversity (and good preservation) in Marine Isotope Stages 2 and 6 and these can be found elsewhere in the Gulf of Mexico, in the Indian Ocean and the South China Sea. Using a "pteropod preservation index" it can be seen that this parallels the changing pCO2 and pH and is clearly related. Research on benthic foraminifera living in high CO2, low pH waters near Ischia (Bay of Naples) shows that it is possible to change the foraminifera living in the environment with a change of pH from 8.14 to 7.8 and 7.6. The changes in the diversity and composition of the foraminiferal assemblages parallel changes seen in other benthic faunas (e.g., gastropods, bivalves, echinoderms and calcareous algae). The reductiuon in foraminiferal diversity and the change in the composition of the assemblage is seen to be triggered by a very small change in pH, and something which - if present trends continue - could be seen in the natural world in a few decades.

  15. The Chicxulub impact is synchronous with the planktonic foraminifera mass extinction at the Cretaceous/Paleogene boundary: new evidence from the Moncada section, Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Arenillas, I.; Arz, J.A.; Grajales-Nishimura, J.M.; Melendez, A.; Rojas-Consuegra, R.

    2016-07-01

    The Moncada section, western Cuba, is one of the few sections across the Cretaceous/Paleogene (K/Pg) boundary in the Gulf of Mexico and Caribbean where an Ir anomaly has been identified toward and above the top of a clastic unit, locally called the Moncada Formation (Fm.). The Moncada Fm. is enriched in ejecta (altered glass spherules, shocked quartz, melt rock fragments, etc.) and represents the local Complex Clastic Unit (CCU) linked to the Chicxulub impact event. This CCU is overlain by a 2-3cm thick bed of Ir-rich, dark, calcareous claystone which represents the “K/T Boundary Clay” at Moncada. All lowermost Danian Planktonic Foraminiferal zones and Acme-Stages (PFAS) were identified, suggesting stratigraphic continuity across the Danian and indicating that the Moncada Fm. is K/Pg boundary in age. High-resolution biostratigraphic data suggest that the mass extinction event of planktonic foraminifera at the K/Pg boundary was more severe than previously suggested. The absence of cosmopolitan, generalist Cretaceous species in the Danian deposits of Moncada supports the hypothesis that only Guembelitria survived the mass extinction triggered by the Chicxulub impact event. The high Ir-concentration and the ejecta-rich clay laminations identified in the lowermost Danian of Moncada (Ancón Fm.) are explained partly as the redeposition of ejecta material eroded and reworked from higher topographic levels, still contaminated by toxic trace elements (e.g., Cu and Ni) of meteoritic origin. These pollutants of meteoritic origin could have affected the ecological conditions of the pelagic environment for thousands of years after the K/Pg boundary, being particularly intense just after the Chicxulub impact. The ecological stress due to the pollutants partly explains the catastrophic mass extinction of planktonic foraminifera at the K/Pg boundary and their subsequent evolutionary radiation. (Author)

  16. Seasonal Variation in Shell Calcification of Planktonic Foraminifera in the NE Atlantic Reveals Species-Specific Response to Temperature, Productivity, and Optimum Growth Conditions.

    Science.gov (United States)

    Weinkauf, Manuel F G; Kunze, José G; Waniek, Joanna J; Kučera, Michal

    2016-01-01

    Using shells collected from a sediment trap series in the Madeira Basin, we investigate the effects of seasonal variation of temperature, productivity, and optimum growth conditions on calcification in three species of planktonic Foraminifera. The series covers an entire seasonal cycle and reflects conditions at the edge of the distribution of the studied species, manifesting more suitable growth conditions during different parts of the year. The seasonal variation in seawater carbonate saturation at the studied site is negligible compared to other oceanic regions, allowing us to assess the effect of parameters other than carbonate saturation. Shell calcification is quantified using weight and size of individual shells. The size-weight scaling within each species is robust against changes in environmental parameters, but differs among species. An analysis of the variation in calcification intensity (size-normalized weight) reveals species-specific response patterns. In Globigerinoides ruber (white) and Globigerinoides elongatus, calcification intensity is correlated with temperature (positive) and productivity (negative), whilst in Globigerina bulloides no environmental forcing is observed. The size-weight scaling, calcification intensity, and response of calcification intensity to environmental change differed between G. ruber (white) and G. elongatus, implying that patterns extracted from pooled analyses of these species may reflect their changing proportions in the samples. Using shell flux as a measure of optimum growth conditions, we observe significant positive correlation with calcification intensity in G. elongatus, but negative correlation in G. bulloides. The lack of a consistent response of calcification intensity to optimum growth conditions is mirrored by the results of shell size analyses. We conclude that calcification intensity in planktonic Foraminifera is affected by factors other than carbonate saturation. These factors include temperature

  17. Coccolithophore and benthic foraminifera distribution patterns in the Gulf of Cadiz and Western Iberian Margin during Integrated Ocean Drilling Program (IODP) Expedition 339

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    Balestra, B.; Grunert, P.; Ausin, B.; Hodell, D.; Flores, J.-A.; Alvarez-Zarikian, C. A.; Hernandez-Molina, F. J.; Stow, D.; Piller, W. E.; Paytan, A.

    2017-06-01

    For the first time during an Integrated Ocean Drilling Program (IODP) Expedition (Exp. 339, Mediterranean Outflow) water samples for living coccolithophore distributions and mudline samples for coccoliths, benthic foraminifera, and geochemical analyses in the underlying surface sediments were collected. In total, 14 water samples (from 5 to 20 m water depth) and 7 mudline samples were gathered at the drill sites. Coccolithophore distributions show spatial variations in species diversity. In particular, assemblages that characterize the Western Iberian Margin differ from those in the Gulf of Cadiz, indicative of oceanographic and environmental controls on the community in the upper ocean (0-20 m depth). Comparison of the living assemblages to those in surface sediments shows differences in the presence of some species, suggesting the influence of post deposition sedimentary processes. Other factors such as the season of sampling and the limited sampling depth may also have a role in the differences recorded. Benthic foraminiferal assemblages seem to be primarily determined by source, quantity and quality of available food. Sites in the Gulf of Cadiz are bathed by Mediterranean Outflow Water (MOW) and characterized by a considerable amount of advected food particles. Elevated epibenthic foraminifera exploit this niche, while arborescent epifaunal and infaunal taxa thrive on food particles falling out of MOW. The combined data suggest different flow speeds and settling of MOW suspension load in the Gulf of Cadiz. In contrast, assemblages from the Western Iberian Margin located farthest from or outside of MOW are determined by local export productivity and mirror trophic conditions in the surface waters. Both assemblages reveal variation in the composition at intermediate and deep water depths along the southern and western Iberian Margins with distance from the Strait of Gibraltar.

  18. Benthic foraminifera across the K/Pg boundary in the Brazos River area (Texas) and Stevns Klint (Denmark): sequence stratigraphy, sea level change and extinctions.

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    Hart, Malcolm; Smart, Christopher; Searle, Sarah; Feist, Sean; Leighton, Andrew; Price, Gregory; Twitchett, Richard

    2010-05-01

    While the majority of micropalaeontologists have concentrated on the planktic foraminifera of the Brazos River succession (in order to define the position of the K/T boundary), there are relatively few studies of the benthic foraminifera published. There are a number of sites available for study, including the Brazos River itself and the tributaries of Cottonmouth Creek and Darting Minnow Creek. There have also been a number of drill cores recovered from the area including the Mullinax - 1 core which we have studied. Almost all of the benthic foraminifera recovered from the Mullinax - 1 core were described by Joseph Cushman (1946) in his monograph. The Corsicana Formation (Kemp Formation of the State Geological Map) of latest Maastrichtian age is overlain by the Littig Member of the Kincaid Formation which includes, at its base, the so-called "Event Bed". The base of this unit is the "impact-defined K/T boundary" of many authors (e.g., Yancey, 1996). The "Event Bed" contains a number of discreet (but thin) sedimentary units including spherule-rich layers, shell lags and a number of hummocky sandstone beds (Gale, 2006). In a recent paper, Keller et al. (2009) have identified an "impact" layer below the "Event Bed" and a K/T boundary higher in the succession that most other authors. In the Mullinax - 1 core, there is a diverse fauna of benthic foraminifera, although the species count is much less than that described by Cushman (1946). This is almost certainly the result of the small sample size available in the small diameter core. There is a distinctive assemblage of mid-outer shelf taxa, including agglutinated foramininfera (Tritaxia, Verneuilina, Plectina, etc.) and aragonitic taxa (Epistomina). The numbers of agglutinated taxa in the Mullinax - 1 core are much reduced at the level of the "Event Bed" and this, coupled with the changes in the planktic fauna, indicates a (fairly) marked drop in sea level. Both Yancey (1996) and Gale (2006) argue that this brings the

  19. Variation in the composition of corals, fishes, sponges, echinoderms, ascidians, molluscs, foraminifera and macroalgae across a pronounced in-to-offshore environmental gradient in the Jakarta Bay-Thousand Islands coral reef complex.

    Science.gov (United States)

    Cleary, D F R; Polónia, A R M; Renema, W; Hoeksema, B W; Rachello-Dolmen, P G; Moolenbeek, R G; Budiyanto, A; Yahmantoro; Tuti, Y; Giyanto; Draisma, S G A; Prud'homme van Reine, W F; Hariyanto, R; Gittenberger, A; Rikoh, M S; de Voogd, N J

    2016-09-30

    Substrate cover, water quality parameters and assemblages of corals, fishes, sponges, echinoderms, ascidians, molluscs, benthic foraminifera and macroalgae were sampled across a pronounced environmental gradient in the Jakarta Bay-Thousand Islands reef complex. Inshore sites mainly consisted of sand, rubble and turf algae with elevated temperature, dissolved oxygen, pH and chlorophyll concentrations and depauperate assemblages of all taxa. Live coral cover was very low inshore and mainly consisted of sparse massive coral heads and a few encrusting species. Faunal assemblages were more speciose and compositionally distinct mid- and offshore compared to inshore. There were, however, small-scale differences among taxa. Certain midshore sites, for example, housed assemblages resembling those typical of the inshore environment but this differed depending on the taxon. Substrate, water quality and spatial variables together explained from 31% (molluscs) to 72% (foraminifera) of the variation in composition. In general, satellite-derived parameters outperformed locally measured parameters.

  20. Impact of seawater pCO2 changes on calcification and on Mg/Ca and Sr/Ca in benthic foraminifera calcite (Ammonia tepida: results from culturing experiments

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    J. Bijma

    2009-04-01

    Full Text Available Evidence is accumulating of increasing concentrations of dissolved carbon dioxide in the ocean and associated acidification impacts on calcifying organisms. Among these organisms, benthic and planktonic foraminifera are responsible for a large amount of the globally precipitated calcium carbonate. Therefore, their response to an acidifying ocean may have important consequences for future inorganic carbon cycling. To assess the sensitivity of benthic foraminifera to changing carbon dioxide levels and subsequent alteration in seawater carbonate chemistry, we cultured specimens of the shallow water species Ammonia tepida at two concentrations of atmospheric CO2 (120 and 2000 ppm and two temperatures (10°C and 15°C. Shell weights and elemental compositions were determined. Results indicate that shell weights decrease with decreasing [CO32−], and increase with decreasing temperature. Changes in [CO32−] or total dissolved inorganic carbon do not affect the Mg partition coefficient. On the contrary, Sr incorporation is enhanced under increasing [CO32−]. Implications of these results for the paleoceanographic application of foraminifera are also discussed.

  1. Decadal- to biennial scale variability of planktic foraminifera in the northeastern Arabian Sea during the last two millennia: evidence for winter monsoon forcing mechanisms

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    Munz, Philipp; Lückge, Andreas; Siccha, Michael; Kucera, Michal; Schulz, Hartmut

    2015-04-01

    The Asian monsoon system is controlling the hydrologic cycle, and thus the agricultural and economic prosperity of the worlds most densely populated region. Strong and moisture-laden winds from the southwest induce upwelling and significant productivity in the western Arabian Sea during boreal summer. During boreal winter, weaker dry and cold surface winds from the northeast nourish ocean productivity mainly in the northeastern Arabian Sea. Instrumental records spanning the last century are too short to understand how the monsoon system reacts to external forcing mechanisms and to accurately determine its natural variability. Compared to the summer monsoon component, the dynamics of the winter monsoon are virtually unknown, due to the lack of adequate archives that are affected only by winter conditions. Here we present a decadal- to biennial-scale resolution record of past winter monsoon variability over the last two millennia, based on census counts of planktic foraminifera from two laminated sediment cores collected offshore Pakistan. One shorter box core (SO90-39KG) spans the last 250 years with an average ~2-year resolution, whereas the longer piston core (SO130-275KL) spans the last 2,100 years with a 10-year resolution. We use Globigerina falconensis as a faunal indicator for winter conditions, a species that is most abundant during winter in the NE Arabian Sea (Peeters and Brummer, 2002; Schulz et al., 2002). Our results show that during the past 2,100 years G. falconensis varied with significant periodicities centered on ˜ 60, ˜ 53, ˜ 40, ˜ 34 and ˜ 29 years per cycle. Some of these periods closely match cycles that are known from proxy records of solar irradiance, suggesting a solar forcing on winter monsoon variability. During the past 250 years G. falconensis varied in correlation with the (11-year) Schwabe and the (22-year) Hale solar cycles. Furthermore, a significant ˜ 7 year cyclicity could indicate a teleconnection to the El Niño Southern

  2. Turnover and paleoenvironmental changes across the Cretaceous/Paleogene boundary at the Galanderud section (Northern Alborz, Iran) based on benthic foraminifera

    Science.gov (United States)

    Asgharianrostami, Masoud; Leckie, R. Mark; Font, Eric; Frontalini, Fabrizio; Koeberl, Christian

    2014-05-01

    A high-resolution quantitative study of benthic foraminifera across the expanded and continuous Cretaceous/Paleogene (K/Pg) boundary at the Galanderud section in northern Iran provides an excellent record of the K/Pg event. The benthic foraminiferal assemblages, in contrast to the planktic foraminifers, did not suffer mass extinction at the K/Pg boundary. Uppermost Maastrichtian assemblages are well preserved and highly diverse. Only ~3% of the benthic species became extinct, including Bolivinoides draco, Eouvigerina subsculptura, Neoflabellina sp. and Praebulimina reussi. Other species are temporarily absent for a short interval after the K/Pg boundary. Benthic foraminifera indicate outer neritic-uppermost bathyal depths during the Plummerita hantkeninoides Zone until 70 cm below the K/Pg boundary. This interval contains abundant species of Bolivinoides draco, Gaudryina pyramidata, Cibicidoides hyphalus, P. reussi, and Sitella cushmani. The paleodepth decreased to outer neritic in the uppermost Maastrichtian based on the dominance of Stensioeina excolata, G. pyramidata, Cibicidoides pseudoacutus, and Coryphostoma incrassata forma gigantea. On the other hand, some species such as P. reussi and C. hyphalus, which are normally found at bathyal depths, decreased in their abundances. These data suggest a sea-level fall at the end of Maastrichtian. Additional evidence for sea-level fall is a decrease of planktic/benthic ratio from ~60% to ~40% in the uppermost Maastrichtian. The K/Pg clay layer is characterized by a high abundance of opportunistic species such as Cibicidoides spp., C. pseudoacutus, and Tappanina selemensis. The drastic change of benthic foraminiferal assemblages coincides with a sharp drop in magnetic susceptibility and %CaCO3, mass extinction of planktic foraminifera, a sharp enrichment in Ir, and a 2.25‰ negative excursion in ∂13C at the K/Pg boundary, which is largely compatible with the catastrophic effects of an asteroid impact on Earth that

  3. Cyanobacteria/Foraminifera Association from Anoxic/Dysoxic Beds of the Agua Nueva Formation (Upper Cretaceous - Cenomanian/Turonian) at Xilitla, San Luis Potosi, Central Mexico

    Science.gov (United States)

    Blanco-Piñón, A.; Maurrasse, F. J.; Rojas-León, A.; Duque-Botero, F.

    2008-05-01

    (> 1 mm in length) are also present oriented parallel to stratification. In addition to filamentous and coccoid cyanobacteria, the limestone beds contain rare benthic foraminifera, common planktic foraminifera, heterohelicids, Rotalipora spp., Rotalipora cf cushmani, Whiteinella spp, W. praehelvetica, which indicate a time interval from the latest Cenomanian to the earliest Turonian. Lithological, paleontological and microfacies data thus indicate that the sediments accumulated in open-marine to semi-restricted platform environments, under low-energy conditions. Primary lamination, pyrite and excellent degree of preservation of fishes, suggest that low oxygen concentration lead to the formation of anoxic/dysoxic conditions during the accumulation of these exceptional deposits, which are coeval with the worldwide development of OAE-2. Planktonic foraminifera and fishes indicate oxygenated conditions in the photic zone, but dysoxic/anoxic conditions near the bottom, which is consistent with the presence of inoceramids and the absence of bioturbation in the sediment.

  4. Reconciling single chamber Mg/Ca with whole test δ18O in surface to deep dwelling planktonic foraminifera from the Mozambique Channel

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    J. Steinhardt

    2014-12-01

    Full Text Available Most planktonic foraminifera migrate vertically through the water column during life, meeting a range of depth-related conditions as they grow and calcify. For reconstructing past ocean conditions from geochemical signals recorded in their shells it is therefore necessary to know vertical habitat preferences. Species with a shallow habitat and limited vertical migration will reflect conditions of the surface mixed layer and short- and meso-scale (i.e. seasonal perturbations therein. Species spanning a wider range of depth habitats, however, will contain a more heterogeneous, intra-specimen variability (i.g. Mg/Ca and δ18O, which is less for species calcifying below the seasonal mixed layer (SML. Here we present results on single-chamber Mg/Ca combined with single shell δ18O and δ13C of surface water Globigerinoides ruber, the thermocline-dwelling Neogloboquadrina dutertrei and Pulleniatina obliquiloculata and the deep dweller Globorotalia scitula from the Mozambique Channel. Species-specific Mg/Ca, δ13C and δ18O data combined with a depth-resolved mass balance model confirm distinctive migration and calcification patterns for each species as a function of hydrography. Whereas single specimen δ18O not always reveal changes in depth habitat related to hydrography (i.g. temperature, measured Mg/Ca of the last chambers can only be explained by active migration in response to changes in temperature stratification. Since species show different responses to changes in hydrography, their shell chemistry can be used to reconstruct different components of the past ocean climate system such as seasonality and depth stratification. Here we present combined single-specimen δ18O and single-chamber Mg/Ca measurements for different species, providing a composite of thermocline and sub-thermocline conditions. These results allow for species-specific reconstruction of calcification depths, using a mass balance model, of four species of planktonic

  5. Marsh benthic Foraminifera response to estuarine hydrological balance driven by climate variability over the last 2000 yr (Minho estuary, NW Portugal)

    Science.gov (United States)

    Moreno, João; Fatela, Francisco; Leorri, Eduardo; De la Rosa, José M.; Pereira, Inês; Araújo, M. Fátima; Freitas, M. Conceição; Corbett, D. Reide; Medeiros, Ana

    2014-09-01

    A high-resolution study of a marsh sedimentary sequence from the Minho estuary provides a new palaeoenvironmental reconstruction from NW Iberian based on geological proxies supported by historical and instrumental climatic records. A low-salinity tidal flat, dominated by Trochamminita salsa, Haplophragmoides spp. and Cribrostomoides spp., prevailed from AD 140-1360 (Roman Warm Period, Dark Ages, Medieval Climatic Anomaly). This sheltered environment was affected by high hydrodynamic episodes, marked by the increase in silt/clay ratio, decrease of organic matter, and poor and weakly preserved foraminiferal assemblages, suggesting enhanced river runoff. The establishment of low marsh began at AD 1380. This low-salinity environment, marked by colder and wet conditions, persisted from AD 1410-1770 (Little Ice Age), when foraminiferal density increased significantly. Haplophragmoides manilaensis and Trochamminita salsa mark the transition from low to high marsh at AD 1730. Since AD 1780 the abundances of salt marsh species (Jadammina macrescens, Trochammina inflata) increased, accompanied by a decrease in foraminiferal density, reflecting climate instability, when droughts alternate with severe floods. SW Europe marsh foraminifera respond to the hydrological balance, controlled by climatic variability modes (e.g., NAO) and solar activity, thus contributing to the understanding of NE Atlantic climate dynamics.

  6. I/Ca ratios in benthic foraminifera from the Peruvian oxygen minimum zone: analytical methodology and evaluation as proxy for redox conditions

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    N. Glock

    2014-07-01

    Full Text Available In this study we explore the correlation of I/Ca ratios in three calcitic and one aragonitic foraminiferal species. I/Ca ratios are evaluated as possible proxies for changes in ambient redox conditions across the Peruvian oxygen minimum zone to the ambient oxygen concentrations in the habitat of the foraminiferal species studied. We test cleaning and measurement methods to determine I/Ca ratios in benthic foraminifera from the Peruvian oxygen minimum zone. All species show a positive trend in their I/Ca ratios as a function of higher oxygen concentrations and these trends are all statistically significant except for the aragonitic species Hoeglundina elegans. The most promising species appears to be Uvigerina striata which shows a highly statistically significant correlation between I/Ca ratios and bottom water (BW oxygenation (I/Ca = 0.032(± 0.004[O2]BW + 0.29(± 0.03, R2 = 0.61, F = 75, P 2]BW correlations, and the individual variability of single tests severely interfere with the observed I/Ca–[O2]BW relationship.

  7. Analysis of two-dimensional shapes by principal component score descriptors: geological interpretations from sand grains, pebbles, benthic foraminifera, and bivalve mollusks

    Energy Technology Data Exchange (ETDEWEB)

    Parks, J.M.

    1987-05-01

    Computerized quantitative shape analysis provides useful geological information not readily obtained in other ways. Principal Components Analysis (PCA) of properly rotated images reduces digitized outlines to a few shape descriptors. R-mode PC loadings, displayed graphically, exhibit the distinctive components of shape (elongation, triangularity, rectangularity, etc) in different orientations. Q-mode estimated PC scores are the shape descriptors for individual objects. Six shape descriptors are adequate to characterize typical geological outline shapes, such as silhouettes of sand grains, pebbles, and fossils. The original outlines are reconstructed using these shape descriptors as proportions for recombining the PC loadings. Proportions and rates of sand mixing from two sources are revealed by shape analysis of populations of sand grains from the Kansas and Missouri rivers sampled above and below their confluence. Unmixing (differential sorting during transport) is revealed by gradual shape changes in sands sampled along 330 mi of the Rio Grande (Del Rio, Texas, to the Gulf of Mexico). Pebbles from the Jackson Hole, Wyoming, area are readily identified as to fluvial or glacial origin by quantified shape. Outline shapes of benthic foraminifera from Maryland Miocene assemblages are classified by cluster and discriminant analyses of PC scores into 20 or more morphological types. Relative proportions of each morpho-type in stratigraphic samples are statistically correlated with independent paleoenvironmental indicators. Intra- and inter-specific changes in shapes of several genera of middle Miocene bivalves from Maryland show three distinct patterns through time: minor irregular changes (= stasis.); abrupt jumps (= punctuated equilibria.); and gradual trends (= gradualism.).

  8. Effective elimination of organic matter interference in boron isotopic analysis by thermal ionization mass spectrometry of coral/foraminifera: micro-sublimation technology combined with ion exchange.

    Science.gov (United States)

    He, Maoyong; Xiao, Yingkai; Ma, Yunqi; Jin, Zhangdong; Xiao, Jun

    2011-03-30

    In order to better estimate the effectiveness of micro-sublimation technology on the elimination of organic matter interference during boron isotopic analysis, a series of improved experiments was carried out using simple apparatus. Recovery rates after micro-sublimation were measured for boric acid solutions with different B contents or different B/organic matter ratios. The improved micro-sublimation procedure combined with ion-exchange technology was then used to test natural samples (coral and foraminifera) for the separation of boron. Our results show that the time taken for 100% recovery of different amounts of B differed and that the proportions of B/organic matter within the natural organic matter have little effect on the relationship between the recovery rates of B and the micro-sublimation times. The experiments further confirm that the organic matter does indeed have an effect on boron isotope analyses by positive thermal ionization mass spectrometry and that the use of micro-sublimation can effectively remove interferences from the organic matter during boron isotopic analysis.

  9. Colonization of over a thousand Cibicidoides wuellerstorfi (foraminifera: Schwager, 1866) on artificial substrates in seep and adjacent off-seep locations in dysoxic, deep-sea environments

    Science.gov (United States)

    Burkett, Ashley M.; Rathburn, Anthony E.; Elena Pérez, M.; Levin, Lisa A.; Martin, Jonathan B.

    2016-11-01

    After ~1 yr on the seafloor at water depths of ~700 m on Hydrate Ridge in the Pacific, eight colonization experiments composed primarily of a plastic mesh cube (from here on refered to as SEA3, for Seafloor Epibenthic Attachment Cubes) were colonized by 1076 Cibicidoides wuellerstorfi on ~1841 cm2 of experimental substrate. This species is typically considered an indicator of well-oxygenated conditions, and recruitment of such large numbers in bottom waters with low dissolved oxygen availability (0.24-0.37 mL/L) indicate that this taxon may not be as limited by oxygen as previously thought. Clues about substrate preferences were evident from the distribution, or lack thereof, of individuals among plastic mesh, coated steel frame, wooden dowels and reflective tape. Abundance, individual size distributions within cage populations and isotopic biogeochemistry of living foraminifera colonizing experimental substrates were compared between active seep and adjacent off-seep experiment locations, revealing potential differences between these environments. Few studies have examined foraminiferal colonization of hard substrates in the deep-sea and to our knowledge no previous study has compared foraminiferal colonization of active seep and off-seep substrates from the same region. This study provides initial results of recruitment, colonization, geochemical and morphological aspects of the paleoceanographically significant species, C. wuellerstorfi, from dynamic deep-sea environments. Further experimental deployments of SEA3s will provide a means to assess relatively unknown ecologic dynamics of important foraminiferal deep-sea species.

  10. Benthic foraminifera records of complex anthropogenic environmental changes combined with geochemical data in a tropical bay of New Caledonia (SW Pacific).

    Science.gov (United States)

    Debenay, Jean-Pierre; Fernandez, Jean-Michel

    2009-01-01

    During the 1950s, open-cast mining led to an increasing input of heavy-metal-rich terrigenous particles in the bays near Nouméa, detected by geochemical and sedimentological analyses. Even though most of terrigenous metal is unavailable, an impact on the benthos was suspected. Simultaneously, the population of Nouméa increased dramatically, which may impact the neighboring bays. Foraminifera were used for assessing this double impact. Thirteen surface samples were collected as a basis for the interpretation of 27 samples from a 54 cm long core. Paradoxically, the general trends in foraminiferal assemblages with time were consistent with a decreasing impact of pollution and continental influence (e.g., increasing species richness, diversity, density, and decreasing percentages of Ammonia tepida). Explanations were found in the urban planning that led to a decrease of freshwater and pollutant inputs. Multiple and contradictory impacts of anthropic activities could be assessed only by a set of complementary tools (i.e., geochemistry and bioindicators).

  11. Late Paleocene-middle Eocene benthic foraminifera on a Pacific seamount (Allison Guyot, ODP Site 865): Greenhouse climate and superimposed hyperthermal events

    Science.gov (United States)

    Arreguín-Rodríguez, Gabriela J.; Alegret, Laia; Thomas, Ellen

    2016-03-01

    We investigated the response of late Paleocene-middle Eocene (~60-37.5 Ma) benthic foraminiferal assemblages to long-term climate change and hyperthermal events including the Paleocene-Eocene Thermal Maximum (PETM) at Ocean Drilling Program (ODP) Site 865 on Allison Guyot, a seamount in the Mid-Pacific Mountains. Seamounts are isolated deep-sea environments where enhanced current systems interrupt bentho-pelagic coupling, and fossil assemblages from such settings have been little evaluated. Assemblages at Site 865 are diverse and dominated by cylindrical calcareous taxa with complex apertures, an extinct group which probably lived infaunally. Dominance of an infaunal morphogroup is unexpected in a highly oligotrophic setting, but these forms may have been shallow infaunal suspension feeders, which were ecologically successful on the current-swept seamount. The magnitude of the PETM extinction at Site 865 was similar to other sites globally, but lower diversity postextinction faunas at this location were affected by ocean acidification as well as changes in current regime, which might have led to increased nutrient supply through trophic focusing. A minor hyperthermal saw less severe effects of changes in current regime, with no evidence for carbonate dissolution. Although the relative abundance of infaunal benthic foraminifera has been used as a proxy for surface productivity through bentho-pelagic coupling, we argue that this proxy can be used only in the absence of changes in carbonate saturation and current-driven biophysical linking.

  12. Temporal changes of environmental impact in the coastal marine area in front of a former mining zone, detected by means of benthic foraminifera

    Science.gov (United States)

    Romano, Elena; Bergamin, Luisa; Maggi, Chiara; Ausili, Antonella

    2016-04-01

    Benthic foraminifera are increasingly used to assess environmental quality of present and past marine environments. They are suitable for the study of ancient environments because their hard and small shells are preserved and abundant in sediment and an adequate number of them can be collected by small samples of sediment cores, supplying reliable data for a statistical approach. The study of foraminiferal assemblages, associated to sediment abiotic parameters, allows to define the anthropogenic impact along the time; reference conditions may be recognized in deep uncontaminated levels. The Sulcis Iglesiente Guspinese area (SW Sardinia, Italy) was affected in past times by intensive mining, which started in mid 19th century and ceased in 1990s. The marine area of Cala Domestica is located few kilometers from the mining district, where mainly galena and sphalerite were exploited. The area houses buildings for storage of minerals receives drainage material from mineral dumps determining a strong enrichment for several metals in the coastal sediments. Sediment core SI/69 was collected by means of vibrocorer in front of Cala Domestica beach, during a vast sampling survey aimed to environmental characterization of marine sediments. The core was subsampled in the laboratory, and a total of 28 levels were collected. Microfaunal, grain size and chemical (As, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn) analyses were carried out on different aliquots of the same level. The quantitative analysis on benthic foraminifera was based on the count of at least 300 specimens per sample. Faunal parameters such as Foraminiferal Number (FN i.e. number of specimens / 1 g dry sediment) and species diversity (- index and H-index) were considered as potential indicators of environmental status. Principal Component Analysis (PCA) showed a group of strongly correlated metals (Ba, Cd, Cu, Hg, Mn, Pb and Zn), associated to the superficial samples. These elements displayed a typical profile along

  13. Relationship between isotopic composition (Δ18O and Δ13C and plaktonic foraminifera test size in core tops from the Brazilian Continental Margin

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    Paula Franco-Fraguas

    2011-12-01

    Full Text Available Stable oxygen (δ18O and carbon (δ13C isotopic signature registered in fossil planktonic foraminifera tests are widely used to reconstruct ancient oceanographic conditions. Test size is a major source of stable isotope variability in planktonic foraminifera found in sediment samples and thus can compromise paleoceanographic interpretations. Test size/stable isotope (δ18O and δ13C relationships were evaluated in two planktonic foraminifer species (Globigerinoides ruber (white and Globorotalia truncatulinoides (right in two core tops from the Brazilian Continental Margin. δ18 Omeasurements were used to predict the depth of calcification of each test size fraction. δ13C offsets for each test size fraction were then estimated. No systematic δ18O changes with size were observed in G. ruber (white suggesting a similar calcification depth range (c.a. 100 m during ontogeny. For G. truncatulinoides (right δ18O values increased with size indicating ontogenetic migration along thermocline waters (250-400 m. δ13C measurements and δ13C offsets increased with size for both species reflecting well known physiological induced ontogenetic-related variability. In G. ruber (white the largest test size fractions (300µm and >355µm more closely reflect δ13C DIC indicating they are best suited for paleoceanographic studies.O tamanho de testa dos foraminíferos é uma importante fonte de variabilidade isotópica (δ18O e δ13C em amostras de sedimento marinho comprometendo as interpretações paloeceanograficas. No presente estudo, avaliou-se a relação entre o sinal isotópico medido em diferentes frações de tamanho de testa das espécies planctônicas, Globigerinoides ruber (branca e Globorotalia truncatulinoides (dextral em amostras de topo de dois testemunhos localizados na Margem Continental Brasileira. Os valores de δ18O foram utilizados para estimar a profundidade de calcificação de cada fração de tamanho. Os desequilíbrios nos valores de

  14. THANETIAN AND EARLY YPRESIAN ORTHOPHRAGMINES (FORAMINIFERA: DISCOCYCLINIDAE AND ORBITOCLYPEIDAE FROM THE CENTRAL WESTERN TETHYS (TURKEY, ITALY AND BULGARIA AND THEIR REVISED TAXONOMY AND BIOSTRATIGRAPHY

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    GYÖRGY LESS

    2007-11-01

    Full Text Available The rich orthophragminid assemblages from the upper Thanetian and lower Ypresian of Turkey are discussed together with the coeval faunas from Spilecco (N Italy and Beloslav (Bulgaria. Their taxonomy, evolution and biozonation in the Western Tethys are revised. Our biometric study is based mainly on a large number of equatorial sections of megalospheric individuals. We present the emended description of Discocyclina seunesi, D. tenuis, Orbitoclypeus multiplicatus, O. bayani and Asterocyclina taramellii. A new species, Nemkovella stockari is introduced. The evolutionary lineages of Discocyclina seunesi, Orbitoclypeus multiplicatus and O. bayani are restored for the first time by using the consistent size-increase of the megalospheric embryon that also allowed introducing some new subspecies (Discocyclina seunesi beloslavensis, D. s. karabuekensis, Orbitoclypeus multiplicatus kastamonuensis, O. bayani kurucasileensis and O. munieri ponticus. By owing the most complete record of Thanetian and early Ypresian orthophragmines from the Western Tethys (using also data from SW France and the Crimean Peninsula we could reconstruct their early evolution. The chronostratigraphical position of some localities was ascertained from planktic and larger benthic foraminifera, as well as calcareous nannoplankton. In the updated orthophragminid zonation (zones are marked by OZ, OZ 1a corresponds to the early Thanetian, OZ 1b to the middle Thanetian. They are distinguished on the base of the evolution of Discocyclina seunesi. In these zones, only two unribbed species of Discocyclina and Orbitoclypeus each are present. Ribbed Orbitoclypeus, genus Asterocyclina and Nemkovella appeared in the redefined OZ 2 zone belonging to the late Thanetian. Discocyclina archiaci and D. dispansa substituted D. seunesi at about the Paleocene/Eocene boundary. The early Ypresian can be subdivided into the OZ 3 and 4 zones that can be distinguished from each other by the different

  15. Spatial and temporal variation in reef-scale carbonate storage of large benthic foraminifera: a case study on One Tree Reef

    Science.gov (United States)

    Doo, Steve S.; Hamylton, Sarah; Finfer, Joshua; Byrne, Maria

    2017-03-01

    Large benthic foraminifera (LBFs) are a vital component of coral reef carbonate production, often overlooked due to their small size. These super-abundant calcifiers are crucial to reef calcification by generation of lagoon and beach sands. Reef-scale carbonate production by LBFs is not well understood, and seasonal fluctuations in this important process are largely unquantified. The biomass of five LBF species in their algal flat habitat was quantified in the austral winter (July 2013), spring (October 2013), and summer (February 2014) at One Tree Reef. WorldView-2 satellite images were used to characterize and create LBF habitat maps based on ground-referenced photographs of algal cover. Habitat maps and LBF biomass measurements were combined to estimate carbonate storage across the entire reef flat. Total carbonate storage of LBFs on the reef flat ranged from 270 tonnes (winter) to 380 tonnes (summer). Satellite images indicate that the habitat area used by LBFs ranged from 0.6 (winter) to 0.71 km2 (spring) of a total possible area of 0.96 km2. LBF biomass was highest in the winter when algal habitat area was lowest, but total carbonate storage was the highest in the summer, when algal habitat area was intermediate. Our data suggest that biomass measurements alone do not capture total abundance of LBF populations (carbonate storage), as the area of available habitat is variable. These results suggest LBF carbonate production studies that measure biomass in discrete locations and single time points fail to capture accurate reef-scale production by not incorporating estimates of the associated algal habitat. Reef-scale measurements in this study can be incorporated into carbonate production models to determine the role of LBFs in sedimentary landforms (lagoons, beaches, etc.). Based on previous models of entire reef metabolism, our estimates indicate that LBFs contribute approximately 3.9-5.4% of reef carbonate budgets, a previously underappreciated carbon sink.

  16. Constraining Seasonal and Vertical Distributions of Planktonic Foraminifera for Paleoclimate Reconstruction Since MIS3 at the Axial Seamount, Juan de Fuca Ridge

    Science.gov (United States)

    Chen, S. L.; Ravelo, A. C.; Clague, D. A.

    2015-12-01

    The California Current is an upwelling region with dynamic interactions between circulation, biological productivity and ecology. A 77 cm piston push core was taken from the Juan de Fuca Ridge Axial Seamount using a Remotely Operated Vehicle (ROV) (2213m, 45.55º N, 130.08º W), an active submarine volcano ~480 km off Oregon's coast. Five radiocarbon dates indicate that the sediment ranges from 42.6 ka at 77 cm to 17.6 ka at 15 cm, with an average sediment accumulation rate of 2.47 cm/ka from 77-15 cm, and an average rate of 0.85 cm/ka during the postglacial period (warm mixed-layer species Orbulina universa are offset from each other, reflecting vertical and seasonal variation among the planktonic foraminifera. Of the three species, G. bulloides shows the least variation in δ18O, possibly indicating that marked changes in temperature are masking changes in the δ18O of seawater due to global ice volume changes. G. bulloides and O. universa δ18O values are similar in MIS 3 and diverge with time, indicating the development of strong seasonal succession of species, since the last glacial maximum. Bulk nitrogen isotopes and nitrogen flux provide additional constraints on upwelling strength and insight into local biological productivity and nutrient dynamics. Obtaining Mg/Ca data will clarify the δ 18O interpretation except deep in the core where metal-bearing authigenic precipitates affect Mg concentrations. These climatic proxies together provide insight into how global climate change and local seamount volcanism impacts regional productivity in the California Current.

  17. Boron incorporation in the foraminifer Amphistegina lessonii under a decoupled carbonate chemistry

    Directory of Open Access Journals (Sweden)

    K. Kaczmarek

    2014-12-01

    BOH4-/HCO3- of the culture media. The latter indicates that boron uptake of A. lessonii features a competition between B(OH4- and HCO3-. Furthermore, the simultaneous determination of B/Ca and δ11B on single specimens allows for assessing the relative variability of these parameters. Among different treatments the B/Ca shows an increasing variability with increasing boron concentration in the test whereas the variability in the isotope distribution is constant.

  18. Uptake of algal carbon and the synthesis of an "essential" fatty acid by Uvigerina ex. gr. semiornata (Foraminifera within the Pakistan margin oxygen minimum zone: evidence from fatty acid biomarker and 13C tracer experiments

    Directory of Open Access Journals (Sweden)

    K. E. Larkin

    2014-01-01

    Full Text Available Foraminifera are an important component of benthic communities in oxygen depleted settings, where they potentially play a~significant role in the processing of organic matter. We tracked the uptake of a 13C-labeled algal food source into individual fatty acids in the benthic foraminiferal species, Uvigerina ex. gr. semiornata, from the Arabian Sea oxygen minimum zone (OMZ. The tracer experiments were conducted on the Pakistan Margin during the late/post monsoon period (August–October 2003. A monoculture of the diatom Thalassiosira weisflogii was 13C-labeled and used to simulate a pulse of phytoplankton in two complementary experiments. A lander system was used for in situ incubations at 140 m and for 2.5 days duration, whilst a laboratory incubation used an oxystat system to maintain ambient dissolved oxygen concentrations. These shipboard experiments were terminated after 5 days. Uptake of diatoms was rapid, with high incorporation of diatom fatty acids into foraminifera after ~2 days in both experiments. Ingestion of the diatom food source was indicated by the increase over time in the quantity of diatom biomarker fatty acids in the foraminifera and by the high percentage of 13C in many of the fatty acids present at the endpoint of both in~situ and laboratory-based experiments. These results indicate that U. ex. gr. semiornata rapidly ingested the diatom food source and that this foraminifera will play an important role in the short-term cycling of organic matter within this OMZ environment. The experiments also suggested that U. ex. gr. semiornata consumed non-labeled bacterial food items, particularly bacteria, and synthesised the polyunsaturated fatty acid 20:4(n-6 de novo. 20:4(n-6 is often abundant in benthic fauna yet its origins and function have remained unclear. This study demonstrates that U. ex. gr. semiornata is capable of de novo synthesis of this "essential fatty acid" and is potentially a major source of this dietary nutrient

  19. Traces of dissolved particles, including coccoliths, in the tests of agglutinated foraminifera from the Challenger Deep (10,897 m water depth, western equatorial Pacific)

    Science.gov (United States)

    Gooday, A. J.; Uematsu, K.; Kitazato, H.; Toyofuku, T.; Young, J. R.

    2010-02-01

    surfaces and no obvious intervening cement. Our observations suggest that (1) small biogenic particles can reach the deepest parts of the ocean intact in rapidly sinking phytodetrital aggregates or faecal pellets and (2) some agglutinated foraminifera living at extreme hadal depths construct a test from biogenic or detrital particles, which subsequently dissolve, leaving imprints and other remnants in the organic matrix of the test.

  20. The effect of bioturbation in pelagic sediments: Lessons from radioactive tracers and planktonic foraminifera in the Gulf of Aqaba, Red Sea

    Science.gov (United States)

    Steiner, Zvi; Lazar, Boaz; Levi, Shani; Tsroya, Shimon; Pelled, Omer; Bookman, Revital; Erez, Jonathan

    2016-12-01

    Studies of recent environmental perturbations often rely on data derived from marine sedimentary records. These records are known to imperfectly inscribe the true sequence of events, yet there is large uncertainty regarding the corrections that should be employed to accurately describe the sedimentary history. Here we show in recent records from the Gulf of Aqaba, Red Sea, how events of the abrupt disappearance of the planktonic foraminifer Globigerinoides sacculifer, and episodic deposition of the artificial radionuclide 137Cs, are significantly altered in the sedimentary record compared to their known past timing. Instead of the abrupt disappearance of the foraminifera, we observe a prolonged decline beginning at core depth equivalent to ∼30 y prior to its actual disappearance and continuing for decades past the event. We further observe asymmetric smoothing of the radionuclide peak. Utilization of advection-diffusion-reaction models to reconstruct the original fluxes based on the known absolute timing of the events reveal that it is imperative to use a continuous function to describe bioturbation. Discretization of bioturbation into mixed and unmixed layers significantly shifts the location of the modeled event. When bioturbation is described as a continuously decreasing function of depth, the peak of a very short term event smears asymmetrically but remains in the right depth. When sudden events repeat while the first spike is still mixed with the upper sediment layer, bioturbation unifies adjacent peaks. The united peak appears at an intermediate depth that does not necessarily correlate with the timing of the individual events. In a third case, a long lasting sedimentary event affected by bioturbation, the resulting peak is rather weak compared to the actual event and appears deeper in the sediment column than expected based on the termination of the event. The model clearly shows that abrupt changes can only endure in the record if a thick sediment layer

  1. Ecological response of benthic foraminifera to the acid drainage from mine areas. An example from the Gromolo torrent mouth (Eastern Ligurian Sea, Italy)

    Science.gov (United States)

    Bergamin, Luisa; Capello, Marco; Carbone, Cristina; Magno, Maria Celia; Consani, Sirio; Cutroneo, Laura; Ferraro, Luciana; Pierfranceschi, Giancarlo; Romano, Elena

    2016-04-01

    Benthic foraminiferal assemblages react in short time to natural and anthropogenic environmental changes and, for this, they are considered as reliable indicators of environmental quality. An interesting application of these indicators is the study of their response to environmental changes in coastal marine areas, affected by dismissed mines and dump areas. The Libiola Fe-Cu sulphide mine was intensively exploited in 19th and 20th centuries, and the activity ended in 1962. The sulphide mineral assemblages consist of pyrite and chalcopyrite, with minor sphalerite and pyrrhotite, in a gangue of quartz and chlorite. The sulphide ore occurs within the Jurassic ophiolites of the Northern Apennines which were subjected to metamorphic and tectonic processes during the subsequent Apennine orogenesis. Waters circulating in the Libiola mine area, and discharging in the adjacent streams and creeks, are strongly polluted due to the diffuse occurrence of Acid Mine Drainage processes. The Gromolo torrent collects these acidic waters enriched of heavy metals which flow into Ligurian Sea. The study area is characterised by a shelf with a gentle slope, mainly constituted by sediment supplied by Entella torrent. The general circulation has trend from East to West and the coastal drift is generally eastwards. A total of 15 marine sediment samples (upper 2 cm) were collected by means of Van Veen grab in the coastal zone close to the Gromolo mouth and analyzed for living (rose Bengal stained) and dead benthic foraminifera, together with grain size, metals and trace elements, and metal fractioning. Quantitative foraminiferal parameters, like as abundance, species diversity, heterogeneity and assemblage composition, were determined and evaluated for environmental purpose. Additionally, possible increase above the natural background level of deformed specimens was considered as indicative of metal contamination. The grain-size analyses highlighted mainly sandy sediments, characterized by

  2. Early Eocene hyperthermal events ETM2, H2 and I1 as recorded by Tethyan planktic foraminifera in the Terche section (northernastern Italy)

    Science.gov (United States)

    D'Onofrio, Roberta; Luciani, Valeria; Giusberti, Luca; Fornaciari, Eliana; Sprovieri, Mario

    2014-05-01

    consequence of the extreme warmth coupled with eutrophic conditions of surface waters. The surface-dwelling acarininids, able to temporarily colonize warmer deeper and nutrient-richer waters previously occupied by Subbotina, better tolerated the relatively high eutrophic conditions which prevented the warm indices Morozovella to thrive. The increased eutrophic conditions can be related to accelerate hydrological cycle, in turn enhanced by the intense warming, as already observed for the PETM in the same area. Calcareous plankton variations during the hyperthermals in a deep-water setting could be affected by selective dissolution susceptibility due to the lysocline rise associated to these events. The planktic foraminiferal Fragmentation Index calculated in correspondence to the MUs of the Terche section presents very low values compared with those observed in other sections of the Belluno Basin across the PETM and the X-event. This indicates that the planktic foraminiferal record is not biased by dissolution and the modifications of assemblages are genuine and representative of the different genera real distributions. Our data on planktic foraminifera prove the strong effect of the hyperthermals events on the biotic component of the upper water column and show that the most intense perturbation was induced by the ETM2 that is characterized by the most pronounced CIE.

  3. 冷泉甲烷渗漏环境底栖有孔虫研究回顾与前景%A REVIEW OF STUDIES ON BENTHIC FORAMINIFERA IN COLD METHANE SEEPS ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    陈芳; 周洋; 刘广虎

    2011-01-01

    This paper briefs the researches and progress of benthic foraminifera in the environment of cold methane seeps related to gas hydrate, with emphasis on its difference with the normal deep sea environment. More and more cold seeps have been found recently with the application of new technology, such as submersible and remotely operated vehicle. Benthic foraminifera could adapt themselves to the high organic and low oxygen gas hydrate related cold methane seep environment, and keep a very negative δ13C value as a record. So far, carbon isotopic(δ13C) excursions in the geologic record have been used as an evidence of methane release from gas hydrate and global temperature change. Such a gas hydrate related cold methane seeps have been found in the South China Sea, and the gas hydrate samples have been successfully recovered from its northern continental slope. It is a necessity to study the benthic foraminifera in the cold methane seep environment for further exploration of gas hydrate in this region.%综述了与天然气水合物有关的冷泉甲烷渗漏环境底栖有孔虫研究成果与应用.冷泉甲烷渗漏环境是区别于一般深海环境的特殊微环境,随着天然气水合物勘探的深入和设备的更新,越来越多的冷泉被发现,冷泉底栖有孔虫的研究随之展开.生活在冷泉环境下的底栖有孔虫群落尤其适应高有机质、低氧、有甲烷释放的特定环境,并能将水合物甲烷碳同位素值异常低的特性记录下来,与无甲烷渗漏环境相比,甲烷渗漏环境底栖有孔虫具有更负的δ13C值,被作为水合物分解释放甲烷事件的记录和解释气候变化的证据之一.我国已在南海北部发现与水合物相关的冷泉并成功获取了天然气水合物实物,开展天然气水合物冷泉甲烷渗漏环境底栖有孔虫研究有其必要性和重要性.

  4. Revisiting carbonate chemistry controls on planktic foraminifera Mg / Ca: implications for sea surface temperature and hydrology shifts over the Paleocene–Eocene Thermal Maximum and Eocene–Oligocene Transition

    Directory of Open Access Journals (Sweden)

    D. Evans

    2015-07-01

    Full Text Available Much of our knowledge of past ocean temperatures comes from the foraminifera Mg / Ca palaeothermometer. Several non-thermal controls on foraminifera Mg incorporation have been identified, of which vital-effects, salinity and secular variation in seawater Mg / Ca are the most commonly considered. Ocean carbonate chemistry is also known to influence Mg / Ca, yet this is rarely considered as a source of uncertainty either because (1 precise pH and [CO32−] reconstructions are sparse, or (2 it is not clear from existing culture studies how a correction should be applied. We present new culture data of the relationship between carbonate chemistry for the surface-dwelling planktic species Globigerinoides ruber, and compare our results to data compiled from existing studies. We find a coherent relationship between Mg / Ca and the carbonate system and argue that pH rather than [CO32−] is likely to be the dominant control. Applying these new calibrations to datasets for the Paleocene–Eocene Thermal Maximum (PETM and Eocene–Oligocene Transition (EOT enable us to produce a more accurate picture of surface hydrology change for the former, and a reassessment of the amount of subtropical precursor cooling for the latter. We show that properly corrected Mg / Ca and δ18O datasets for the PETM imply no salinity change, and that the amount of precursor cooling over the EOT has been previously underestimated by ∼ 2 °C based on Mg / Ca. Finally, we present new laser-ablation data of EOT-age Turborotalia ampliapertura from St Stephens Quarry (Alabama, for which a solution ICPMS Mg / Ca record is available (Wade et al., 2012. We show that the two datasets are in excellent agreement, demonstrating that fossil solution and laser-ablation data may be directly comparable. Together with an advancing understanding of the effect of Mg / Casw, the coherent picture of the relationship between Mg / Ca and pH that we outline here represents a step towards producing

  5. Revisiting carbonate chemistry controls on planktic foraminifera Mg / Ca: implications for sea surface temperature and hydrology shifts over the Paleocene-Eocene Thermal Maximum and Eocene-Oligocene transition

    Science.gov (United States)

    Evans, David; Wade, Bridget S.; Henehan, Michael; Erez, Jonathan; Müller, Wolfgang

    2016-04-01

    Much of our knowledge of past ocean temperatures comes from the foraminifera Mg / Ca palaeothermometer. Several nonthermal controls on foraminifera Mg incorporation have been identified, of which vital effects, salinity, and secular variation in seawater Mg / Ca are the most commonly considered. Ocean carbonate chemistry is also known to influence Mg / Ca, yet this is rarely examined as a source of uncertainty, either because (1) precise pH and [CO32-] reconstructions are sparse or (2) it is not clear from existing culture studies how a correction should be applied. We present new culture data of the relationship between carbonate chemistry and Mg / Ca for the surface-dwelling planktic species Globigerinoides ruber and compare our results to data compiled from existing studies. We find a coherent relationship between Mg / Ca and the carbonate system and argue that pH rather than [CO32-] is likely to be the dominant control. Applying these new calibrations to data sets for the Paleocene-Eocene Thermal Maximum (PETM) and Eocene-Oligocene transition (EOT) enables us to produce a more accurate picture of surface hydrology change for the former and a reassessment of the amount of subtropical precursor cooling for the latter. We show that pH-adjusted Mg / Ca and δ18O data sets for the PETM are within error of no salinity change and that the amount of precursor cooling over the EOT has been previously underestimated by ˜ 2 °C based on Mg / Ca. Finally, we present new laser-ablation data of EOT-age Turborotalia ampliapertura from St. Stephens Quarry (Alabama), for which a solution inductively coupled plasma mass spectrometry (ICPMS) Mg / Ca record is available (Wade et al., 2012). We show that the two data sets are in excellent agreement, demonstrating that fossil solution and laser-ablation data may be directly comparable. Together with an advancing understanding of the effect of Mg / Casw, the coherent picture of the relationship between Mg / Ca and pH that we outline

  6. New Mediterranean Marine biodiversity records (June 2013

    Directory of Open Access Journals (Sweden)

    I. SIOKOU

    2013-04-01

    Full Text Available This paper concerns records of species that have extended their distribution in the Mediterranean Sea. The finding of the rare brackish angiosperm Althenia filiformis in the island of Cyprus is interesting since its insertion in the Red Data Book of the Flora of Cyprus is suggested. The following species enriched the flora or fauna lists of the relevant countries: the red alga Sebdenia dichotoma (Greece, the hydrachnid mite Pontarachna adriatica (Slovenia, and the thalassinid Gebiacantha talismani (Turkey. Several alien species were recorded in new Mediterranean localities. The record of the burrowing goby Trypauchen vagina in the North Levantine Sea (Turkish coast, suggests the start of spreading of this Lessepsian immigrant in the Mediterranean Sea. The findings of the following species indicate the extension of their occurrence in the Mediterranean Sea: the foraminifer Amphistegina lobifera (island of Zakynthos, Greece, the medusa Cassiopea andromeda (Syria, the copepod Centropages furcatus (Aegean Sea, the decapod shrimp Melicertus hathor (island of Kastellorizo, Greece, the crab Menoethius monoceros (Gulf of Tunis, the barnacles Balanus trigonus, Megabalanus tintinnabulum, Megabalanus coccopoma and the bivalves Chama asperella, Cucurbitula cymbium (Saronikos Gulf, Greece.

  7. New Mediterranean Marine biodiversity records (June 2013

    Directory of Open Access Journals (Sweden)

    I. SIOKOU

    2013-04-01

    Full Text Available This paper concerns records of species that have extended their distribution in the Mediterranean Sea. The finding of the rare brackish angiosperm Althenia filiformis in the island of Cyprus is interesting since its insertion in the Red Data Book of the Flora of Cyprus is suggested. The following species enriched the flora or fauna lists of the relevant countries: the red alga Sebdenia dichotoma (Greece, the hydrachnid mite Pontarachna adriatica (Slovenia, and the thalassinid Gebiacantha talismani (Turkey. Several alien species were recorded in new Mediterranean localities. The record of the burrowing goby Trypauchen vagina in the North Levantine Sea (Turkish coast, suggests the start of spreading of this Lessepsian immigrant in the Mediterranean Sea. The findings of the following species indicate the extension of their occurrence in the Mediterranean Sea: the foraminifer Amphistegina lobifera (island of Zakynthos, Greece, the medusa Cassiopea andromeda (Syria, the copepod Centropages furcatus (Aegean Sea, the decapod shrimp Melicertus hathor (island of Kastellorizo, Greece, the crab Menoethius monoceros (Gulf of Tunis, the barnacles Balanus trigonus, Megabalanus tintinnabulum, Megabalanus coccopoma and the bivalves Chama asperella, Cucurbitula cymbium (Saronikos Gulf, Greece.

  8. Recent foraminifera of the Sao Francisco river delta, Sergipe, Brazil: a proposal for the ecological and environmental diagnostic model; Foraminiferos recentes do delta do Rio Sao Francisco, Sergipe (Brasil): uma proposta de modelo ecologico e de diagnostico ambiental

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    Recent foraminifera assemblages were studied to determine an ecological model of species distribution, diversity, equability and confining degree, with implications to environmental diagnosis and paleoenvironmental reconstructions. The study area is inserted in a sector from Sao Francisco River delta, with interconnected channels and a lagoon connected to the ocean. Besides the biotic variables, sediment salinity and granulometry was considered. An agglomerative hierarchical clustering (AHC) was performed and it was recognized three bio facies distributed along the sector: Miliammina/Arenoparrella in the channels, and Ammonia/Elphidium and Quinqueloculina at the lagoon. The diversity and equability values increase from the Miliammina/Arenoparrella biofacies to the Ammonia/Elphidium and Quinqueloculina biofacies. The confining indices show environments ranging from confined (channels) to different degrees of low restricted to marine influence. From the results obtained, it is possible to recognize that environments dominated by textulariines are characterized by low diversity, equability and high confining degree. Environments dominated by rotaliines and miliolines tend to be more diversified, equitable and low restricted to marine influence. The results are similar to other obtained in other Brazilian estuarine environments, differing only on dominance by some species (author)

  9. CALIBRATION OF MG/CA THERMOMETRY OF THE BENTHIC FORAMINIFERA FROM THE BERING SEA%白令海底栖有孔虫壳体镁钙比值对水团温度的响应

    Institute of Scientific and Technical Information of China (English)

    叶黎明; 邱中炎; 雷吉江

    2012-01-01

    The Mg/Ca ratio of benthic foraminiferal shells was often used as a paleo-temperature proxy for the deep water mass. In this study, we used the Mg/Ca and δ18 O of the benthic foraminifera Uvigerina peregrine to calibrate the Mg/Ca thermometry so as to reveal its feasibility in the Bering Sea. The results show that the calcification temperature calculated with δ18O is much lower than the modern temperature of the water mass, and can not objectively reflect the control of temperature over the Mg/Ca. There is no evidence to relate the Mg/Ca with the modern temperature of water mass in the region if the water depth is shallower than 150 m. In the deep sea, however, a good exponential function expressed as Mg/Ca = 0. 69 * e0.43*T was discovered with a standard error of 0. 2 ℃and the Mg/Ca-temperature sensitivity may reach 43%℃‐1at low temperature in the Bering Sea.%底栖有孔虫壳体Mg/Ca是重建深层水团古温度的主要指标.通过分析表层沉积物样品中底栖有孔虫Uvigerina peregrina壳体的Mg/Ca和δ18 O,探讨了“Mg/Ca古温度重建方法”在白令海低温水体中的可行性及其转换函数.结果表明,利用U.peregrina壳体δ18 O换算的“结壳温度”明显低于“现代水团温度”,不能客观反映温度对Mg/Ca的控制作用;可能受季节性变化的影响,水深小于150 m样品中U.peregrina壳体的Mg/Ca与“现代水团温度”之间并没有表现出明显的相关性,但是,在深海区两者之间却呈现出良好的指数关系:Mg/Ca=0.69*e0.43*T.该公式指出白令海低温水体中Mg/Ca对温度的敏感性约为43%℃-1,由其估算的温度误差约为0.2℃.

  10. Oceanographic parameters in continental margin of the State of Ceará (northeastern Brazil) deduced from C and O isotopes in foraminifers.

    Science.gov (United States)

    Marques, Wanessa S; Menor, Eldemar de A; Sial, Alcides N; Manso, Valdir A V; Freire, Satander S

    2007-03-01

    Specimens of Recent foraminifera of Amphistegina radiata, Peneroplis planatus and Globigerinoides ruber, from fifty samples of surface sediments of the continental margin of the State of Ceará, Brazil, have been analyzed for carbon and oxygen isotopes to investigate oceanographic parameters and determine the values of delta18O of the oceanic water. From a comparison between values of delta18O obtained for ocean water using the linear equations by (Craig and Gordon 1965) and the one by Wolff et al. (1998), it became evident that the former yielded a more reliable value (0.2 per thousand SMOW) than the latter. Lower values of delta18O for the ocean water in this continental margin resulted from continental water influence. Values of 18O (-0.3 per thousand to -1.5 per thousand PDB for benthic foraminifera and -0.6 per thousand to -2.4 per thousand PDB for planktic foraminifera), attest to a variation of temperatures of oceanic water masses, in average, between 20 to 22 degrees C in deep water and 24 to 27 degrees C, in surface water. Values of delta13C from +3.2% to -0.2 per thousand PDB (benthic foraminifera) reflect a variation in the apparent oxygen utilization (AOU) in the continental margin and indicate that the environments of bacteriological decomposition of organic matter are not continuous along the investigated area.

  11. 南海北部有孔虫碳氧同位素特征与晚第四纪水合物分解的响应关系%Respondence Between Carbon and Oxygen Isotopic Characteristics of Foraminifera from the Northern South China Sea and Late Quaternary Hydrate Released

    Institute of Scientific and Technical Information of China (English)

    曹超; 雷怀彦

    2012-01-01

    为探寻晚第四纪以来水合物分解事件在南海北部甲烷渗漏环境下有孔虫中的记录,对南海北部陆坡2个区块的沉积柱状样有孔虫碳氧同位素组成和测年分析发现,底栖有孔虫Uvigerina spp.碳同位素值为-2.12‰~-0.21‰,浮游有孔虫Globigerinoides ruber.氧同位素值为-3.11‰ ~-0.60‰,ZD3、ZS5 2个柱状样孔底年龄分别为26616、64090 a,对应了氧同位素Ⅲ、Ⅳ期末期,有孔虫碳同位素负偏的层位与氧同位素Ⅱ、Ⅳ期(冷期)层位相对应,负偏程度达到了-2‰,与布莱克海台和墨西哥湾等地区晚第四纪沉积层中有孔虫碳氧同位素组成相似.分析认为:研究区是典型的甲烷渗漏环境,该区在氧同位素Ⅱ、Ⅳ期,由于全球海平面下降,导致海底压力减小,天然气水合物分解释放,具轻碳同位素的大量甲烷释放进入海底溶解无机碳(DIC)池并记录在有孔虫壳体内,造成有孔虫碳同位素负偏;同时在有孔虫负偏层位黄铁矿和自生碳酸盐较发育,进一步证实了有孔虫碳同位素受甲烷影响较大,而海洋生产力的降低和早期成岩作用对有孔虫碳同位素负偏的影响较小.%To search the records of the gas hydrate decomposition events under methane seepage condition since the late Quaternary, carbon and oxygen isotopes analysis and radiometric dating of foraminifera from sediment cores collected from three different blocks of the northern slope of the South China Sea are carried out. The results show:l) the carbon isotope value of benthic foraminifera Uvigerina spp. is -2. 12 ‰ to -0. 21 ‰ and oxygen isotope value of planktonic foraminifera Globigerinoides ruber is -3. 11 ‰ to -0. 60 ‰; 2) the age of the two cores at the bottom of ZD3 and ZS5 drills are 26 616 a and 64 090 a respectively, corresponding to the early oxygen isotope stage DI and the end of IV; 3) negative -skewed layer of carbon isotope (up to -2 ‰) corresponds to that of oxygen

  12. Remunerative role of foraminifera in coastal ecosystem

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    observational data for climate (temperature and rainfall) is available for only the last 100-150 years, paleoclimatic reconstruction has to be based on indirect evidences (proxy data) of climatic changes. Attempts are made to use fossilised floral evidence...

  13. Proton pumping accompanies calcification in foraminifera

    Science.gov (United States)

    Toyofuku, Takashi; Matsuo, Miki Y.; de Nooijer, Lennart Jan; Nagai, Yukiko; Kawada, Sachiko; Fujita, Kazuhiko; Reichart, Gert-Jan; Nomaki, Hidetaka; Tsuchiya, Masashi; Sakaguchi, Hide; Kitazato, Hiroshi

    2017-01-01

    Ongoing ocean acidification is widely reported to reduce the ability of calcifying marine organisms to produce their shells and skeletons. Whereas increased dissolution due to acidification is a largely inorganic process, strong organismal control over biomineralization influences calcification and hence complicates predicting the response of marine calcifyers. Here we show that calcification is driven by rapid transformation of bicarbonate into carbonate inside the cytoplasm, achieved by active outward proton pumping. Moreover, this proton flux is maintained over a wide range of pCO2 levels. We furthermore show that a V-type H+ ATPase is responsible for the proton flux and thereby calcification. External transformation of bicarbonate into CO2 due to the proton pumping implies that biomineralization does not rely on availability of carbonate ions, but total dissolved CO2 may not reduce calcification, thereby potentially maintaining the current global marine carbonate production.

  14. 东沙西南海域表层底栖有孔虫碳同位素对冷泉活动的指示%CARBON ISOTOPE OF BENTHIC FORAMINIFERA AND ITS IMPLICATIONS FOR COLD SEEPAGE IN THE SOUTHWESTERN AREA OFF DONGSHA ISLANDS,SOUTH CHINA SEA

    Institute of Scientific and Technical Information of China (English)

    向荣; 方力; 陈忠; 张兰兰; 杜恕环; 颜文; 陈木宏

    2012-01-01

    The depleted carbon isotope (δ13C) of benthic foraminifera was regarded as an important indicator of ancient cold methane seepage. In this study carbon isotope analyses were carried out for 6 benthic fo-raminiferal species from 4 surface sediments with carbonate nodules in the southwestern area off. Dongsha Islands, South China Sea. The carbon isotope of epibenthic species of Discanomalina semiungulata , Cibi-cides wullerstorfi, Cibicides pseudoungerianus and Cibicides lobatulus all show apparent negative excursions compared to the δ13C values at the control sites in the SCS and, in particular, all values of D. semiungulata are depleted. The endobenthic Lenticulina orbicularis also has some negative carbon isotope excursions , while endobenthic Uvigerina auberiana reveals abnormal positive values compared with the controlling sites. The amplitude of δ13 C variability of D. semiungulata (2. ll%o), L. orbicularis (1. 49%o), C. pseudoungerianus (2. 08%o) and U. auberiana (1. 98%o) are apparent larger than that at the controlling sites ((0. 4%o) , and also larger than the δ13C variability (1. l%o) of benthic foraminifera during the last two glacial-interglacial cycles of the SCS. Living benthic foraminifera D. semiungulata and C. lobatulus, which attached on a tube worm, both show obvious depletion of δ13C. We consider that the depleted δ13C values with significantly larger variability observed in benthic foraminiferal species in the southwestern are-a off Dongsha Islands, SCS are possibly caused by cold seeping activity. And the negative excursion of carbon isotope in the living attached benthic foraminifera may indicate an active cold seepage existed in the studied area. We suggest that the epibenthic D. semiungulata be used as a potential indicator of cold seepage in the SCS.%底栖有孔虫碳同位素负偏记录是冷泉活动的重要指标之一.对南海北部东沙西南海域4个含碳酸盐结核的表层沉积物样品中的6种底栖有孔虫进

  15. Distribución de foraminíferos bentónicos (Protozoa: Foraminiferida en la ensenada Quillaipe (41°32' S; 72°44' O, Chile: Implicaciones para el estudio del nivel del mar Distribution of benthic foraminifera (Protozoa: Foraminiferida in the Quillaipe Inlet (41°32' S; 72°44' W, Chile: Implications for sea level studies

    Directory of Open Access Journals (Sweden)

    LEONARDO D FERNÁNDEZ

    2010-12-01

    Full Text Available Los foraminíferos de las marismas salobres son utilizados como indicadores del cambio producido en el nivel del mar durante el Holoceno. No obstante, los foraminíferos de las marismas de Chile han sido escasamente estudiados por lo que se desconoce la factibilidad de utilizarlos para este fin. Para subsanar esto se desarrolló una investigación en el intermareal de la ensenada de Quillaipe, Chile, con los objetivos de determinar los foraminíferos y su distribución vertical; analizar los parámetros que explican su distribución y determinar las especies que son útiles como indicadoras del nivel del mar. Los resultados revelaron 18 especies (nueve aglutinadas y nueve calcáreas distribuidas en dos grandes Zonas (I y II. La Zona I se restringió a la parte más alta y vegetada del intermareal (marisma y estuvo habitada solo por taxa aglutinados. Aquí se registraron bajos valores de diversidad (H' = 0.567, pH (6.6 y salinidad (18.7 y un dominio de la especie aglutinada Haplophragmoides manilaensis. En cambio, la Zona II se limitó a la zona menos elevada y sin vegetación del intermareal (llanura de marea y estuvo habitada por una comunidad calcárea-aglutinada. Contrariamente, los valores de diversidad (H' = 0.909, pH (7.7 y salinidad (32.8 fueron más altos, y la especie dominante fue la calcárea Ammonia beccarii. Por otro lado, la asociación aglutinada Trochamminita salsa-Jadammina macrescens se restringió a la parte más alta de la marisma y a los valores más bajos de salinidad y pH. Estos antecedentes permiten concluir que la distribución de los foraminíferos está controlada por la salinidad, el pH y la elevación del intermareal y que la asociación Trochamminita salsa-Jadammina macrescens son indicadoras del máximo nivel del mar en la ensenada de Quillaipe.Saltmarsh foraminifera are used as indicators of sea-level change which occurs during the Holocene. In Chile however, the saltmarsh foraminifera have been poorly studied, so

  16. Living (stained calcareous benthic foraminifera from recent sediments off Concepción, central-southern Chile (~36° S Foraminíferos bentónicos calcáreos vivos (teñidos en sedimentos recientes de Concepción, Chile centro-sur (~36° S

    Directory of Open Access Journals (Sweden)

    RAÚL TAPIA

    2008-09-01

    Full Text Available This study examines onshore-offshore and vertical distribution of living (Rose Bengal stained benthic foraminifera (> 180 μm fraction from three sediment stations along a bathymetric transect off Concepción, Chile (station 18 = 88 m water depth, station 26 = 120 m, station 40 = 1,030 m, within and below the oxygen minimum zone. All cores were collected in austral winter. Calcareous foraminifera dominated the three stations. The species composition, living foraminifera density, and vertical distribution patterns within the sediment changed in accordance with bottom water dissolved oxygen concentration and food availability. Onshore-offshore pattern revealed overall highest living foraminiferal densities at shelf stations 18 and 26 where bottom water dissolved oxygen was lowest (~ 0.2 mL-1 and content in labile organic matter highest. Within the sediment, maximum relative abundances (50-60 % of living organisms were found in the 0-1 cm interval at the organic-rich and oxygen-poor shelf stations 18 and 26. In the well-oxygenated (2.7 mL-1 slope station 40, 70 % of living foraminifera were observed deeper than the first centimeter. The number of species and the contribution of the > 250 μm fraction to the total fauna larger than 180 μm increased offshore. Nonionella auris (d'Orbigny dominated at stations 18 and 26 while a more diverse foraminifera fauna was found at station 40. This study provides the first quantitative data on living benthic foraminifera in the area; seasonal and interannual changes are not addressed.Este estudio examina la distribución costa-océano y vertical de los foraminíferos bentónicos calcáreos (fracción > 180 im vivos (teñidos en tres estaciones a lo largo de un transecto batimétrico frente al área de Concepción, Chile (estación 18 = 88 m, estación 26 = 120 m, estación 40 = 1.030 m de profundidad, dentro y bajo la zona mínima de oxígeno. Todos los testigos de sedimento fueron recolectados durante el per

  17. An updated review of alien species on the coasts of Turkey

    Directory of Open Access Journals (Sweden)

    M.E. CINAR

    2012-12-01

    Full Text Available This 2010 review of alien species along the coasts of Turkey represents a total of 400 alien species belonging to 14 systematic groups. The present paper also reports the first findings ofVanderhorstia mertensi in the Aegean Sea (Gökova Bay, Chama adspersa in the Sea of Marmara andMya arenaria in the Aegean Sea. A total of 124 new alien species was determined within the last 5 years. Mollusca had the highest number of species (105 species, followed by Polychaeta (75 species, Crustacea (64 species and Pisces (58 species. The highest number of alien species (330 species were encountered on the Levantine coast of Turkey, followed by the Aegean Sea (165 species, Sea of Marmara (69 species and Black Sea (20 species. The Suez Canal (66% of the total number of alien species is the main vector for species introductions to the coasts of Turkey, followed by the ship-mediated transport (30%. The majority of species (306 species, 76% of total number of species have become established in the area, while 59 species are classified as casual (15%, 23 species as questionable (6% and 13 species as cryptogenic (3%. One new alien species was introduced to the coasts of Turkey every 4 weeks between 1991 and 2010. The majority of aliens were found on soft substratum (198 species in shallow waters (0-10 m (319 species. Some species such asCaulerpa racemosa, Amphistegina lobifera, Amphisorus hemprichii, Rhopilema nomadica, Mnemiopsis leidyi, Hydroides spp., Ficopomatus enigmaticus, Charybdis longicollis, Rapana venosa, Asterias rubens, Siganus spp. and Lagocephalus sceleratus show high invasive characters, and have great impacts both on the prevailing ecosystems and humans.

  18. An updated review of alien species on the coasts of Turkey

    Directory of Open Access Journals (Sweden)

    M.E. CINAR

    2011-05-01

    Full Text Available This 2010 review of alien species along the coasts of Turkey represents a total of 400 alien species belonging to 14 systematic groups. The present paper also reports the first findings ofVanderhorstia mertensi in the Aegean Sea (Gökova Bay, Chama adspersa in the Sea of Marmara andMya arenaria in the Aegean Sea. A total of 124 new alien species was determined within the last 5 years. Mollusca had the highest number of species (105 species, followed by Polychaeta (75 species, Crustacea (64 species and Pisces (58 species. The highest number of alien species (330 species were encountered on the Levantine coast of Turkey, followed by the Aegean Sea (165 species, Sea of Marmara (69 species and Black Sea (20 species. The Suez Canal (66% of the total number of alien species is the main vector for species introductions to the coasts of Turkey, followed by the ship-mediated transport (30%. The majority of species (306 species, 76% of total number of species have become established in the area, while 59 species are classified as casual (15%, 23 species as questionable (6% and 13 species as cryptogenic (3%. One new alien species was introduced to the coasts of Turkey every 4 weeks between 1991 and 2010. The majority of aliens were found on soft substratum (198 species in shallow waters (0-10 m (319 species. Some species such asCaulerpa racemosa, Amphistegina lobifera, Amphisorus hemprichii, Rhopilema nomadica, Mnemiopsis leidyi, Hydroides spp., Ficopomatus enigmaticus, Charybdis longicollis, Rapana venosa, Asterias rubens, Siganus spp. and Lagocephalus sceleratus show high invasive characters, and have great impacts both on the prevailing ecosystems and humans.

  19. Foraminíferos bentónicos aglutinados de los Depósitos turbidíticos. Área Nápoles, Sur de San Marcos de Tarrazú, Costa Rica Agglutinated foraminifera from turbiditic deposits, Nápoles Area, South of San Marcos, Tarrazú, Costa Rica

    Directory of Open Access Journals (Sweden)

    Lolita Campos

    2012-12-01

    ú, located within a broad structural belt not yet fully defined at the boundary between and Térraba and Valle Central sedimentary basins, the sample LOR-10 provided an faunal assemblage of exclusively agglutinated benthic foraminifera. As there were not found planktonic foraminifera, biostratigraphic determinations were not possible to obtain. Of the identified individuals, these correspond to 3 suborders, 9 superfamilies and 33 species. Regarding to the Shannon diversity index (H, the result for paleoecological interpretations was of H = 1.4, indicating conditions of marshes and marginal marine environments. On the other hand, the benthic foraminifera identified in the sample to species level, have very wide ranges of existence: from Triassic to Recent. From the point of view regarding to paleoecological salinity, there were determined the following percentages: rotaliids 53.3%, texturaliids 41.9% and miliolids 2.2%, values that are indicative of brackish lagoon environments, estuarine and shelf, these mix of environments is indicative of an allochthonous reworked deposit. The presence of Portatrochammina sp. (4.3% that appears between 500 and 2000 m, but is abundant approximately between 600 and 700 m and of Cibicides lobatulus (3.2% indicative of the upper middle bathyal zone (500-1500 m, confirm the interpretation of the deposit environment as a submarine fan of middle bathyal waters. Likewise, the preeminence of agglutinated foraminifera suggests an important contribution of detritus into the basin. Finally, stratified, cold, deep, basins with high sedimentation rates favor the preservation of agglutinated foraminifera instead carbonate ones.

  20. ANALYSES OF FORAMINIFERS MICROFAUNA AS ENVIRONMENTAL BIOINDICATORS IN KOTOK BESAR, KOTOK KECIL AND KARANG BONGKOK ISLANDS, KEPULAUAN SERIBU, DKI JAKARTA PROVINCE

    Directory of Open Access Journals (Sweden)

    Nazar Nurdin

    2017-07-01

    Full Text Available Kepulauan Seribu is a well-known destination of marine tourism in Indonesia. Inevitably, the place has been affected by human activities. Hence it is important to preserve and conserve the area so as it is still suitable for reef community to grow and develop. One of the methods to evaluate the feasibility for reef environment is calculated by FoRAM Index (FI values. Benthic foraminifera as a tool for environmental bioindicators were collected from 15 marine surface sediment samples in the vicinity areas of Kotok Besar, Kotok Kecil and Karang Bongkok islands in Kepulauan Seribu to assess the FI values. Approximately 20 genera of benthic foraminifera were found in the study area. The genera are dominated by Amphistegina and Calcarina along with Operculina, Quinqueloculina, Peneroplis, and Discorbis. The finding signifies reef flat environment as the dominant morphology, although the presence of fore slope is also observed particularly at the western part of Kotok Besar island. The assemblages of Operculina and Quinqueloculina suggest that the abundance of benthic foraminifera is influenced not only by the morphology of seafloor, but also by tidal current and terrestrial influence. The FI formula using foraminifers found in the study area results values above 4, thus the area can be reviewed as a decent environment for reef growth and development.

  1. Aspects of the biodiversity of brackish water foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmy, K.V.; Rao, K.K.

    , exclusively, 13 curves, viz. linear, quadratic, cubic, fourth and higher degree (up to tenth degree) polynomials, reciprocal linear, reciprocal quadratic, log function, log-log function, reciprocal cubic, recip- rocal fourth degree polynomial, exponential...

  2. Holocene planktonic foraminifera from the shelf sediments off Kerala Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Twenty-two planktonic foraminifers were identified from a few samples collected aboard INS KISTNA at 9~'N and 76~'E, at 89 metres depth from the bottom sediment-water interface. A few of the more characteristic features of each are described. Some...

  3. The earliest Foraminifera from southern Shaanxi,China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Vase-shaped microfossils(VSMs) described herein mainly occur as isolated individuals in thin bedded siltstone and silty carbonate of the Gaojiashan Member of the upper Ediacaran Dengying Formation(ca.551-541 Ma).Although these fossils are abundant,chained tests or other types of colonial aggregates have not been observed.Specimens in the siltstones can easily be isolated from the host rocks by ultrasonic vibrators.Compared with the co-occurring fossils Gaojiashania and Conotubus,VSMs are rarely pyritized,yet they are always three-dimensionally persevered with little deformation,suggesting that their tests were sturdy and possibly mineralized.Petrological observation and elemental mapping reveal two types of tests that are respectively calcareous and siliceous in composition.Calcareous tests typically consist of two to three crypto-crystal laminae,somewhat resembling bilamellar walls of foraminifers.Siliceous tests consist of fine-grained particles agglutinated with siliceous cement,similar to agglutinated walls of foraminifers.The Gaojiashan VSMs are broadly similar,at least in gross morphology,to the testate amoebae-like VSMs,but their relative large sizes(600-2400 μm) and possibly mineralized(rather than organic) tests argue against this comparison.They also show some similarities to other protozoans,especially tintinnids.However,tintinnids have robust pesudochitinous loricae consisting of both secreted and agglutinated materials.Moreover,tintinnid loricae differ in shape from the Gaojiashan VSM tests in having a constricted aboral end(sometimes with a caudal appendix) and a flaring oral opening.If the Gaojiashan VSMs are indeed related to foraminifers,they indicate that foraminifers were important players in late Ediacaran communities.

  4. Ecosystem recovery after hypoxia: what can foraminifera indicate?

    NARCIS (Netherlands)

    Brouwer, G.M.|info:eu-repo/dai/nl/341050040

    2014-01-01

    The many resources and services provided by coastal ecosystems (e.g. food, fertile soils), make these areas valuable habitats for marine life and human occupation. Expanding human population sizes and the associated increase of human exploitation of coastal zones has made these areas prone to

  5. Potentiality of foraminifera in deciphering paleo-sea levels

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    -bearing sediment layer in Goa and Lothal Dockyard at the head of the Gulf of Khambhat (Cambay) are discussed as case-studies of sea level rise. The results indicate the possibility of higher sea level between 4,300 and 6,000 years BP. Similarly, bottom sediments...

  6. MOLECULAR PHYLOGENY OF LARGE MILIOLID FORAMINIFERA. (R825869)

    Science.gov (United States)

    AbstractThe foraminiferal superfamily Soritacea belongs to the suborder Miliolina and is divided in two families, Peneroplidae and Soritidae, the latter one comprising two subfamilies, Archaiasinae and Soritinae. Phylogenetic relationships of 11 genera of soritid fora...

  7. Reconstructing Ocean pH with Boron Isotopes in Foraminifera

    Science.gov (United States)

    Foster, Gavin L.; Rae, James W. B.

    2016-06-01

    In order to better understand the effect of CO2 on the Earth system in the future, geologists may look to CO2-induced environmental change in Earth's past. Here we describe how CO2 can be reconstructed using the boron isotopic composition (δ11B) of marine calcium carbonate. We review the chemical principles that underlie the proxy, summarize the available calibration data, and detail how boron isotopes can be used to estimate ocean pH and ultimately atmospheric CO2 in the past. δ11B in a variety of marine carbonates shows a coherent relationship with seawater pH, in broad agreement with simple models for this proxy. Offsets between measured and predicted δ11B may in part be explained by physiological influences, though the exact mechanisms of boron incorporation into carbonate remain unknown. Despite these uncertainties, we demonstrate that δ11B may provide crucial constraints on past ocean acidification and atmospheric CO2.

  8. Reproductive behaviour of benthic foraminifera: A key to palaeoclimate

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    Many benthic foraminiferal species exhibit dimorphism associated with reproduction. The two resultant forms are known as microspheric and megalospheric forms. Culture studies, though limited in number, show that ratios of these forms are affected...

  9. The Foraminifera of Piscadera Bay, Curaçao

    NARCIS (Netherlands)

    Hofker, J.

    1971-01-01

    Piscadera Bay is situated 4 km West of Willemstad, Curaçao, between two limestone hills which have a height of about 100 m. It is a drowned river system, the entrance of which is almost completely blocked by a bar of coral debris reaching to about 2 meters above sea level. The following parts may be

  10. MOLECULAR PHYLOGENY OF LARGE MILIOLID FORAMINIFERA. (R825869)

    Science.gov (United States)

    AbstractThe foraminiferal superfamily Soritacea belongs to the suborder Miliolina and is divided in two families, Peneroplidae and Soritidae, the latter one comprising two subfamilies, Archaiasinae and Soritinae. Phylogenetic relationships of 11 genera of soritid fora...

  11. Evolution and molecular phylogeny of Cibicides and Uvigerina (Rotaliida, Foraminifera)

    NARCIS (Netherlands)

    Schweizer, M.

    2006-01-01

    Foraminifers are a group of unicellular organisms present in all the oceans and seas, in fresh water and even in soil. An important number of foraminifers build a shell, often called a 'test' that can be preserved in the fossil record. These tests are extensively used in the field of paleoceanograph

  12. Paleogene reworked foraminifera in Recent sediments off Daman, Western India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Setty, M.G.A.P.

    bar which rises abruptly from a depth of 43 m to a height of 7-20 m running parallel to the coast. Based on this ratio, the study area may be divided into four zones. It is considered that the Paleogene of Surat-Broach area is the source for reworking...

  13. Bipolar gene flow in deep-sea benthic foraminifera

    DEFF Research Database (Denmark)

    Pawlowski, J.; Fahrni, J.; Lecroq, B.

    2007-01-01

    Despite its often featureless appearance, the deep-ocean floor includes some of the most diverse habitats on Earth. However, the accurate assessment of global deep-sea diversity is impeded by a paucity of data on the geographical ranges of bottom-dwelling species, particularly at the genetic leve...

  14. Foraminifera from the deep lake terraces, Vestfold hills, Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Williams, R.; Kerry, K.R.

    and were especially obvious in the @iCassidulina, Cibicides, Nonionella, Hyalinea@@, and @iTruncatulina@@. Causative factors for this dissolution include the very high salinity, very low temperature, and high dissolved carbon dioxide contents of the waters...

  15. Agglutinated foraminifera from the shelf of east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Almeida, F.; Setty, M.G.A.P.

    belonging to six families, in a depth zone of 35-222 m of the east-coast of India (between Visakhapatnam and Masulipatnam along the continental shelf-slope region) in terms of lithology, faunal assemblage and their percentage distribution are discussed...

  16. Shelf edge regime and foraminifera off Pondicherry, Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    as they are reported to be 'extinct' in the present day Atlantic. Similarly, the presence of @iRotalia nicobarensis@@ and @iTriloculina tricarinata@@ is significant as they are known to occur since the Miocene time. Relative abundance of such robust forms as @i...

  17. Variaciones estacionales de los foraminíferos planctónicos durante 2005-2006 frente a Iquique (20°S y Concepción (36°S, Chile Seasonal variations of planktic foraminifera during 2005-2006 off Iquique (20°S and Concepción (36°S, Chile

    Directory of Open Access Journals (Sweden)

    Nathalie Gajardo

    2012-07-01

    Full Text Available Se estudió por primera vez las variaciones estacionales de los foraminíferos planctónicos frente a las costas de Iquique (20°S, 70°W y Concepción (36°S, 74°W, Chile. Las muestras fueron recolectadas mediante trampas de sedimentos ubicadas en dos profundidades: 1.000 y 2.300 m, entre septiembre y diciembre 2005, bajo condiciones normales (con surgencias permanentes y ausencia del evento El Niño en la zona norte, y entre enero y octubre durante el evento El Niño 2006 en la zona sur (con surgencias estacionales. Se determinó un total de 23 especies, 22 de las cuales se recolectaron frente a Iquique y 16 frente a Concepción. Además, se determinó el flujo de carbonato de calcio de foraminíferos, flujo de individuos y diversidad para definir patrones faunísticos en dichas áreas, de diferentes condiciones oceanográficas. Los resultados mostraron que en Iquique, bajo condiciones normales, se produjo un constante flujo de individuos y carbonato, con máximos en septiembre y octubre 2005, confirmando la presencia de surgencia costera en este período. Por el contrario, en Concepción, bajo condiciones El Niño (2006, el flujo de individuos y carbonato de calcio presentó máximos durante la época estival evidenciando surgencias, que sin embargo, son de menor duración (enero-febrero respecto a lo descrito en condiciones normales para esta área. La diversidad fue mayor a menor en profundidad en ambas zonas, permaneciendo constante durante todo el período en la zona norte, a diferencia de la zona sur, cuyos mayores valores se observaron durante la época estival coincidiendo con los afloramientos costeros en esta área.We studied for first time the seasonal variations of planktic foraminifera off Iquique (20°S, 70°W and Concepcion (36°S, 74°W, Chile. The samples were collected by sediment traps located at two depths: 1000 and 2300 m between September and December 2005, under normal conditions (with permanent upwelling and the

  18. Oceanographic parameters in continental margin of the State of Ceará (northeastern Brazil deduced from C and O isotopes in foraminifers

    Directory of Open Access Journals (Sweden)

    Wanessa S. Marques

    2007-03-01

    Full Text Available Specimens of Recent foraminifera of Amphistegina radiata, Peneroplis planatus and Globigerinoides ruber, from fifty samples of surface sediments of the continental margin of the State of Ceará, Brazil, have been analyzed for carbon and oxygen isotopes to investigate oceanographic parameters and determine the values of delta18O of the oceanic water. From a comparison between values of delta18O obtained for ocean water using the linear equations by (Craig and Gordon 1965 and the one by Wolff et al. (1998, it became evident that the former yielded a more reliable value (0.2‰ SMOW than the latter. Lower values of delta18O for the ocean water in this continental margin resulted from continental water influence. Values of 18O (-0.3‰ to -1.5‰ PDB for benthic foraminifera and -0.6‰ to -2.4‰ PDB for planktic foraminifera, attest to a variation of temperatures of oceanic water masses, in average, between 20 to 22ºC in deep water and 24 to 27ºC, in surface water. Values of delta13C from +3.2‰ to -0.2‰ PDB (benthic foraminifera reflect a variation in the apparent oxygen utilization (AOU in the continental margin and indicate that the environments of bacteriological decomposition of organic matter are not continuous along the investigated area.Amphistegina radiata, Peneroplis planatus e Globigerinoides ruber, presentes em cinqüenta amostras de sedimentos superficiais da margem continental do Estado do Ceará, Brasil, foram analisados quanto à composição isotópica do Oxigênio e Carbono para investigar parâmetros oceanográficos, e um possível valor de delta18O do oceano. Foi feita uma comparação entre as equações lineares de Craig e Gordon (1965 e de Wolff et al. (1998, e verificou-se que a primeira equação foi mais apropriada para o cálculo de delta18O do oceano, na área estudada, encontrando-se um valor de 0,2‰ SMOW. Os menores valores de delta18O estão associados à desembocadura dos rios, refletindo a influ

  19. Reef calcifiers are adapted to episodic heat stress but vulnerable to sustained warming

    Science.gov (United States)

    Reymond, Claire E.; Rieder, Vera; Hallock, Pamela; Rahnenführer, Jörg; Westphal, Hildegard; Kucera, Michal

    2017-01-01

    Shallow marine ecosystems naturally experience fluctuating physicochemical conditions across spatial and temporal scales. Widespread coral-bleaching events, induced by prolonged heat stress, highlight the importance of how the duration and frequency of thermal stress influence the adaptive physiology of photosymbiotic calcifiers. Large benthic foraminifera harboring algal endosymbionts are major tropical carbonate producers and bioindicators of ecosystem health. Like corals, they are sensitive to thermal stress and bleach at temperatures temporarily occurring in their natural habitat and projected to happen more frequently. However, their thermal tolerance has been studied so far only by chronic exposure, so how they respond under more realistic episodic heat-event scenarios remains unknown. Here, we determined the physiological responses of Amphistegina gibbosa, an abundant western Atlantic foraminifera, to four different treatments––control, single, episodic, and chronic exposure to the same thermal stress (32°C)––in controlled laboratory cultures. Exposure to chronic thermal stress reduced motility and growth, while antioxidant capacity was elevated, and photosymbiont variables (coloration, oxygen-production rates, chlorophyll a concentration) indicated extensive bleaching. In contrast, single- and episodic-stress treatments were associated with higher motility and growth, while photosymbiont variables remained stable. The effects of single and episodic heat events were similar, except for the presumable occurrence of reproduction, which seemed to be suppressed by both episodic and chronic stress. The otherwise different responses between treatments with thermal fluctuations and chronic stress indicate adaptation to thermal peaks, but not to chronic exposure expected to ensue when baseline temperatures are elevated by climate change. This firstly implies that marine habitats with a history of fluctuating thermal stress potentially support resilient

  20. The impact of ocean acidification on the functional morphology of foraminifera.

    Science.gov (United States)

    Khanna, Nikki; Godbold, Jasmin A; Austin, William E N; Paterson, David M

    2013-01-01

    Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism's survival and fitness.

  1. FORAMINIFERA AS BIOINDICATORS IN CORAL REEF ASSESSMENT AND MONITORING: THE FORAM INDEX. (R825869)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  2. Pollution effects monitoring with foraminifera as indices in the Thana creek, Bombay area

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    In the study area, the pollution effect on the foraminiferids is intense, hence highly reliable and measurable. The relative sensitivity of tolerance of the biota is sharply variable and dependent upon the nature of the pollutants discharged...

  3. Larger foraminifera from a relict structure off Karwar western Indian continental margin

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    @iGloboquadrina conglomerata, G. hexagona@@ and dextrally coiled @iNeogloboquadrina pachyderma typica@@ (reported earlier). The occurrence of some of the planktonics was suggestive of upwelling and their record in the sediment was indicative...

  4. Oxygen isotopic analyses of individual planktic foraminifera species: Implications for seasonality in the western Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Niitsuma, N.; Naik, S.S.

    iscussion P aper | D iscussion P aper | D iscussion P aper | D iscussion P aper | Thompson, L. G., Davis, H. E., Henderson, K. A., Mosley-thompson, E., Lin, P. N., Beer, J., Synal, H. A., Cole-Doi, J., and Bolzan, H. F.: Tropical climate instability...

  5. Distribution patterns of Recent planktonic foraminifera in surface sediments of the western continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    and to map the distribution of 11 abundant and/or ecologically important planktonic foramini- feral species; (2) to evaluate the extent to which patterns of foraminiferal abundance and diversity in Recent bottom sediments reflect the details of surface...

  6. Shallow water benthic foraminifera as proxy for natural versus human-induced environmental change

    NARCIS (Netherlands)

    Nooijer, L.J. de

    2007-01-01

    Ecosystem composition and functioning is not only subjected to human-induced alterations, ecosystems also subjected to natural (e.g. climate-induced) variability. To quantify human impacts on ecosystems, these natural fluctuations must be accounted for. Since long-term biological monitoring programs

  7. Quaternary history of sea ice in the western Arctic Ocean based on foraminifera

    Science.gov (United States)

    Polyak, Leonid; Best, Kelly M.; Crawford, Kevin A.; Council, Edward A.; St-Onge, Guillaume

    2013-11-01

    Sediment cores from the Northwind Ridge, western Arctic Ocean, including uniquely preserved calcareous microfossils, provide the first continuous proxy record of sea ice in the Arctic Ocean encompassing more than half of the Quaternary. The cores were investigated for foraminiferal assemblages along with coarse grain size and bulk chemical composition. By combination of glacial cycles and unique events reflected in the stratigraphy, the age of the foraminiferal record was estimated as ca 1.5 Ma. Foraminiferal abundances, diversity, and composition of benthic assemblages, especially phytodetritus and polar species, were used as proxies for sea-ice conditions. Foraminiferal Assemblage Zone 2 in the Lower Pleistocene indicates diminished, mostly seasonal sea ice, probably facilitated by enhanced inflow of Pacific waters. A gradual decrease in ice-free season with episodes of abrupt ice expansion is interpreted for the Mid-Pleistocene Transition, consistent with climatic cooling and ice-sheet growth in the Northern Hemisphere. A principal faunal and sedimentary turnover occurred near the Early-Middle Pleistocene boundary ca 0.75 Ma, with mostly perennial sea ice indicated by the overlying Assemblage Zone 1. Two steps of further increase in sea-ice coverage are inferred from foraminiferal assemblage changes in the "Glacial" Pleistocene by ca 0.4 and 0.24 Ma, possibly related to hemispheric (Mid-Brunhes Event) and Laurentide ice sheet growth, respectively. These results suggest that year-round ice in the western Arctic was a norm for the last several 100 ka, in contrast to rapidly disappearing summer ice today.

  8. Modern planktonic foraminifera. By Ch Hemleben, M. Spindler and O.R. Anderson

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    stream_size 2 stream_content_type text/plain stream_name Indian_J_Mar_Sci_19_304.pdf.txt stream_source_info Indian_J_Mar_Sci_19_304.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  9. A note on the Pavonina flabelliformis D'Orbigny (benthic foraminifera) from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Khare, N.

    . flabelliformis in modern sediments off Karwar suggests and updates the lower depth limit to 33 metre as against reported from deeper regions in previous studies. This will have significant bearing in paleodepth studies of sedimentary strata having fossils...

  10. Pre-monsoon living planktonic foraminifera from the Southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Naidu, P.D.; Muralinath, A.S.

    . References BE, A. W. H. and HUTSON, W. H. (l977) Ecologic and biogeographic patterns of planktonic foraminiferal life and fossil assemblages. Micropaleontology, v. 23, pp. 369-414. COLBORN, J. G. (1975) Thermal structure of Indian Ocean. International Indian...

  11. Foraminifera from the Chilka Lake on the east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Venugopal, P.; Gopalakrishnan, T.C.; Rajagopal, M.D.

    exiguus, Ammonia beccarii (Linne) and A. tepida are the most abundant species in the fauna. A study of biofacies shows that the fauna is characterized by Miliammina in the inner lagoon fades and by Ammonia beccarii (Linne) in the outer lagoon/channel fades...

  12. Addressing environmental issues through foraminifera – Case studies from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    The present global scenario poses multiple environmental problems such as the green house effect, ozone holes, global warming and consequential sea level rise, all being attributed to anthropogenic contributions. Obviously, there is an increased...

  13. Assessing the effect of calcein incorporation on physiological processes of benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Kurtarkar, S.R.; Saraswat, R.; Nigam, R.; Banerjee, B.; Mallick R.; Naik, Dinesh K.; Singh, D.P.

    and temperature. The average final size of the specimens is calculated from the size of all living specimens on the last day of measurement. The reported variability is the mean of the standard deviation of the average size of all living specimens taken...., 2008; Dissard et al., 2010; Raitzsch et al., 2010). In many studies, the living specimens used in the experiments are collected in the field, and have already secreted part of their shell in natural conditions. The early chambers of such specimens...

  14. The impact of ocean acidification on the functional morphology of foraminifera.

    Directory of Open Access Journals (Sweden)

    Nikki Khanna

    Full Text Available Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism's survival and fitness.

  15. INSOLENTITHECA EMEND., PROTO INSOLENTITHECA N. GEN., AND CALIGELLIDAE EMEND., PERMANENT CYSTS OF PALAEOZOIC FORAMINIFERA?

    Directory of Open Access Journals (Sweden)

    DANIEL VACHARD

    2004-11-01

    Full Text Available Insolentitheca was interpreted as a microproblematicum, a foraminiferal test, or a syzygial cyst. Arguments are listed versus syzygial cysts or ordinary foraminiferal agglutinates, and for permanent cysts with probable infaunal life. Protoinsolentitheca fundamenta n. gen. n. sp. is described, which links Insolentitheca and the Caligellidae. Some elements of nomenclature are introduced to describe the particular tests of the Caligellidae. These taxa could be basically represented by an infaunal naked or chitinaceous foraminifer, which secretes during its lifetime a calcified perimeter denominated the chimney, only present in the Caligellidae. To this initial secretion are added two types of "agglutinated" and bioeroded tests: the fundamental in Protoinsolentitheca and Insolentitheca, and the bricks, in Insolentitheca only. 

  16. LEPINOCONUS CHIOCCHINII GEN. N., N. SP., A CONICAL AGGLUTINATED FORAMINIFERA FROM THE UPPER CRETACEOUS OF ITALY

    Directory of Open Access Journals (Sweden)

    ERZIKA CRUZ-ABAD

    2017-04-01

    Full Text Available A new conical agglutinated foraminifer, Lepinoconus chiocchinii gen n., n. sp. from the lower Campanian shallow-water platform deposits of the Lepini Mountains (central Apennines, Italy, is described. It has a pseudo-keriothecal wall structure, uniserial arrangement of the adult chambers and multiple apertures. The exoskeleton is constituted by beams (main and intercalary continuous from one chamber to the next, while the endoskeleton bears pillars. The new taxon is included in the Coskinolinidae family. Lepinoconus chiocchinii gen. n., n. sp. is known from southern Italy, Greece and Albania.

  17. Widespread occurrence of nitrate storage and denitrification among Foraminifera and Gromiida

    DEFF Research Database (Denmark)

    Ochoa, Elisa Pina; Høgslund, Signe; Geslin, Emmanuelle

    2010-01-01

    Benthic foraminifers inhabit a wide range of aquatic environments including open marine, brackish, and freshwater environments. Here we show that several different and diverse foraminiferal groups (miliolids, rotaliids, textulariids) and Gromia, another taxon also belonging to Rhizaria, accumulate...

  18. Differential response of benthic meiofauna to anoxia with special reference to Foraminifera (Protista: Sarcodina)

    NARCIS (Netherlands)

    Moodley, L.; Van der Zwaan, G.J.; Herman, P.M.J.; Kempers, L.; Van Breugel, P.

    1997-01-01

    Sediments collected from the northwestern Adriatic Sea (Mediterranean) were exposed to anoxic bottom-water conditions for more than 2 mo in order to examine the resistance of dominant meiobenthic taxa to prolonged anoxia. Copepods appeared to be most sensitive to anoxia, with densities being reduced

  19. Shallow water benthic foraminifera as proxy for natural versus human-induced environmental change

    NARCIS (Netherlands)

    Nooijer, L.J. de

    2007-01-01

    Ecosystem composition and functioning is not only subjected to human-induced alterations, ecosystems also subjected to natural (e.g. climate-induced) variability. To quantify human impacts on ecosystems, these natural fluctuations must be accounted for. Since long-term biological monitoring programs

  20. Influence of monsoon upwelling on the planktonic foraminifera off Oman during Late Quaternary

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    foraminifer species mass accumulation rates (flux), coiling direction, test size and isotopic values primarily based on the results from the Ocean Drilling Program (ODP) Site 723A (18°03N, 57°37E, water depth 808m) from the Oman Margin, Arabian Sea... Drilling Program (ODP) Site 723A from the Oman Margin, Arabian Sea. Neogloboquadrina pachyderma Fluctuations of the sinistral morphotype fluxes of Neogloboquadrina pachyderma follow closely the variation in the upwelling index in being higher...

  1. Cytologic and Genetic Characteristics of Endobiotic Bacteria and Kleptoplasts of Virgulinella fragilis (Foraminifera).

    Science.gov (United States)

    Tsuchiya, Masashi; Toyofuku, Takashi; Uematsu, Katsuyuki; Brüchert, Volker; Collen, John; Yamamoto, Hiroyuki; Kitazato, Hiroshi

    2015-01-01

    The benthic foraminifer Virgulinella fragilis Grindell and Collen 1976 has multiple putative symbioses with both bacterial and kleptoplast endobionts, possibly aiding its survival in environments from dysoxia (5-45 μmol-O2 /L) to microxia (0-5 μmol-O2 /L) and in the dark. To clarify the origin and function of V. fragilis endobionts, we used genetic analyses and transmission electron microscope observations. Virgulinella fragilis retained δ-proteobacteria concentrated at its cell periphery just beneath the cell membranes. Unlike another foraminifer Stainforthia spp., which retains many bacterial species, V. fragilis has a less variable bacterial community. This suggests that V. fragilis maintains a specific intracellular bacterial flora. Unlike the endobiotic bacteria, V. fragilis klepto-plasts originated from various diatom species and are found in the interior cytoplasm. We found evidence of both retention and digestion of kleptoplasts, and of fragmentation of the kleptoplastid outer membrane that likely facilitates transport of kleptoplastid products to the host. Accumulations of mitochondria were observed encircling endobiotic bacteria. It is likely that the bacteria use host organic material for carbon oxidation. The mitochondria may use oxygen available around the δ-proteobacteria and synthesize adenosine triphosphate, perhaps for sulfide oxidation.

  2. Widespread occurrence of nitrate storage and denitrification among Foraminifera and Gromiida

    DEFF Research Database (Denmark)

    Ochoa, Elisa Pina; Høgslund, Signe; Geslin, Emmanuelle

    2010-01-01

    Benthic foraminifers inhabit a wide range of aquatic environments including open marine, brackish, and freshwater environments. Here we show that several different and diverse foraminiferal groups (miliolids, rotaliids, textulariids) and Gromia, another taxon also belonging to Rhizaria, accumulat...

  3. Does carbonate ion control planktonic foraminifera shell calcification in upwelling regions?

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.S.; Godad, S.P.; Naidu, P.D.

    controlled by surface water [CO sup(=) sub(3)]. Therefore it is suggested here that shell weights of G. ruber and G. bulloides cannot be utilized to reconstruct surface water [CO sup(=) sub(3)] in this region....

  4. A Simple Biomineralization Model to Explain Li, Mg, and Sr Incorporation into Aragonitic Foraminifera and Corals

    Science.gov (United States)

    Marchitto, T. M.; Bryan, S. P.; Montagna, P.

    2011-12-01

    The relationships between growth temperature and individual metal/Ca ratios in biogenic aragonites may be fundamentally perturbed by at least two processes: Ca pumping and Rayleigh fractionation. We suggest that the ratio Li/Mg is insensitive to both processes. Theoretically this is because the two elements experience negligible leakage through the Ca pump and very low partitioning into aragonite, leading to relatively constant Li/Mg in the calcifying fluid. This behavior may be related to the small ionic radii of both elements compared to Ca. As a result, Li/Mg is well explained by the temperature dependence of Li and Mg partitioning into inorganic aragonite, lending promise to its utility as a paleothermometer. Coral Sr/Ca is shown to be consistent with this model if the Ca pump is leaky with respect to Sr.

  5. New data on the trace metal composition of the planktonic foraminifera microfossils of the Atlantic Ocean

    Science.gov (United States)

    Demina, L. L.; Oskina, N. S.

    2016-11-01

    This paper reports new data on the trace metal composition of planktonic foraminifer shells from surface sediments and cores (fraction >0.1 mm) in the central part of the Atlantic Ocean. This investigation has made it possible to identify a considerable accumulation of trace elements from water due to calcite entering into the crystal lattice under biomineralization and adsorption on the shell surface and pores, despite the fact that the shells are depleted in trace elements relative to pelagic clays. The trace element content in planktonic foraminifer microfossils is characterized by temporal variability, which is the most pronounced in long cores (Holocene-Upper Pleistocene) and reflects the sedimentation paleoenvironment in the ocean.

  6. Campano-Maastrichtian foraminifera from onshore sediments in the Rio del Rey Basin, Southwest Cameroon

    Science.gov (United States)

    Njoh, Oliver Anoh; Victor, Obiosio; Christopher, Agyingi

    2013-03-01

    Campanian-Maastrichtian marine sediments outcrop in five genetically linked sedimentary basins along the West African coast in the Gulf of Guinea, from the Douala Basin in Cameroon to the Anambra Basin in Nigeria. These sediments in the more centrally located Rio del Rey Basin have been the least studied. Therefore, the geologic history of this region has merely been speculative. The Rio del Rey Basin like the adjacent Niger Delta is producing hydrocarbon from the offshore Tertiary sedimentary interval in which all studies have been focused, neglecting the onshore Cretaceous sediments. Outcrops in the basin are rare, small and highly weathered. Samples from some of these sediments have yielded a few Planktonic and dominantly benthonic foraminiferal assemblages. The long-ranging heterohelix and hedbergellids characterized the planktics while the species Afrobolivina afra which is a well known diagnostic taxon for Campanian-Maastrichtian sediments in West African basins clearly dominate the benthic assemblage. Its occurrence in association with other Upper Cretaceous forms such as Bolivina explicata, Praebulimina exiqua, Gabonita lata, Ammobaculites coprolithiformis amongst others, formed the basis on which this age was assigned to the sediments sampled from the Rio del Rey Basin. Hence, this work has undoubtedly established the much needed link in this regional geologic history and correlates these sediments with the Logbaba and Nkporo Formations in the Douala Basin in Cameroon and the southeastern Nigerian Sedimentary Basins. Thus, these units were all deposited during this same geologic period and probably controlled by the same geologic event.

  7. Benthic foraminifera morphology: A tool for paleoenvironmental and paleowater depth interpretations

    Energy Technology Data Exchange (ETDEWEB)

    Gary, A.C. (Univ. of South Carolina, Columbia (United States))

    1991-03-01

    Quantitative analysis of morphologic variation within recent benthic foraminiferal species from the northwestern Gulf of Mexico reveals changes in some populations that parallel environmental gradients (i.e., morphoclines). Such relationships likely reflect the influence of particular environmental variables on the morphology of the individual during its development and can be used as an indicator of paleoenvironment and paleowater depth. The specimens studied were taken from the top 5 cm of sediment of box cores collected on the shelf and slope. The two-dimensional outline of each specimen was converted to a Fourier series in closed form, and patterns in the data and their correlation to physical parameters were explored using SAWVEC and correlation analysis. Of the specimens studied, seven exhibited a correlation between morphology and environment: Bolivina albatrossi, Bolivina subaenariensis mexicana, Bolivina subspinescens, Bulimina marginata, Cibicidoides pachyderma, Sphaeroidina bulloides, and Uvigerina peregrina. Paleowater depth and paleoenvironmental interpretations based on environmentally induced morphologic changes within species complement techniques presently being used based on species distributions by utilizing some different species and providing greater precision in the upper- and middle-bathyal zones.

  8. Foraminifera as indicators of slope environments in the northern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Culver, S.J. (Old Dominion Univ., Norfolk, VA (United States))

    1991-03-01

    Paleobathymetric reconstructions of the northern Gulf of Mexico are based mainly on models derived from distribution patterns of modern benthic foraminiferal taxa. This method of paleoenvironmental analysis is commonly supplemented by information derived from species diversity patterns, planktonic/benthonic ratios, and shell-type ratios. Based on these lines of evidence, environment subdivision of the northern Gulf slope in the 1960s recognized two zones, upper bathyal (200 to 500 m) and lower bathyal (500 to 2,000 m). Later studies defined three bathyal depth zones; upper bathyal (200 to 500 m), middle bathyal (500 to 1,000 m), and lower bathyal (1,000 to 2,000 m). Both qualitative and quantitative analyses indicate that this tripartite pattern is the natural subdivision of the slope that can be recognized in foraminiferal assemblages at both the species and generic level. The movement of exploration onto the slope in the 1980s stimulated attempts to further subdivide the bathyal realm. For example, a recent study defined a model consisting of seven a priori bathyal depth zones and statistically investigated zone membership on the basis of generic assemblages. Another approach involved analysis of the depth distribution of assemblages defined by shape of test rather than taxonomic composition. All of these studies utilize modern models of depth relationships but such models become less precise in increasingly older strata. To address this problem, time-specific paleobathymetric models can be derived for fossil foraminiferal assemblages organized along datum planes.

  9. Morphotype analysis of deep-sea benthic foraminifera from the northwest Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, B.H.; Fois, E. (Duke Univ., Durham, NC (USA))

    1990-12-01

    An analysis of benthic foraminiferal morphotypes, based on test shape, mode of coiling and presence or absence of surface pores, was carried out on benthic foraminiferal data collected from the Gulf of Mexico by Phleger (1951). The morphotypes show distinct depth patterns and are used to determine the depth distribution of foraminiferal microhabitats in the Gulf of Mexico. The plano-convex morphotype has generally low values ({le}10%) in relatively shallow depths (<1,000 m) and a range of values of up to 60% in deeper water (>1,000 m). The biconvex morphotype has values of <40% in water <500 m, and a range of values below this interval. The flat ovoid, tapered or cylindrical and flat tapered morphotypes have maxima in the upper 2,000 m, with a large range of values, while lower values are found in the 2,000-4,000 m interval. A summation of the epifaunal and infaunal morphotypes shows that infaunal taxa dominate in relatively shallow waters from 100 m-<1,300 m, and epifaunal taxa dominate generally at depths of >2,000 m, with the 1,300-2,000 m interval being transitional with variable values. The infaunal-epifaunal depth pattern is similar to that observed in the Norwegian Sea. The infaunal-epifaunal transition between 1,300 and 2,000 m is close to the upper or lower depth limits of many species, and the authors suggest that these depth limits are related in part to the microhabitat preferences of the taxa.

  10. A Decline in Benthic Foraminifera following the Deepwater Horizon Event in the Northeastern Gulf of Mexico

    OpenAIRE

    Patrick T Schwing; Isabel C. Romero; Brooks, Gregg R.; Hastings, David W.; Rebekka A Larson; Hollander, David J.

    2015-01-01

    Sediment cores were collected from three sites (1000-1200 m water depth) in the northeastern Gulf of Mexico from December 2010 to June 2011 to assess changes in benthic foraminiferal density related to the Deepwater Horizon (DWH) event (April-July 2010, 1500 m water depth). Short-lived radioisotope geochronologies (²¹⁰Pb, ²³⁴Th), organic geochemical assessments, and redox metal concentrations were determined to relate changes in sediment accumulation rate, contamination, and redox conditions ...

  11. Environmental changes during the Paleocene–Eocene Thermal Maximum in Spitsbergen as reflected by benthic foraminifera

    Directory of Open Access Journals (Sweden)

    Jenö Nagy

    2013-07-01

    Full Text Available The study deals with environmental changes during the Paleocene–Eocene Thermal Maximum (PETM and its background conditions in Spitsbergen through analysis of benthic foraminiferal assemblages (FA in a section drilled in the Paleogene Central Basin. The impact of this extreme global warming occurs here in prodelta shelf mudstones composing the lower part of the Gilsonryggen Member (Frysjaodden Formation. The start of the PETM perturbation is marked by a faunal turnover, in which the medium-diversity circumpolar Reticulophragmium assemblage was replaced by a low-diversity Trochammina fauna. During the hyperthermal period, benthic foraminiferal diversity decreased severely, while the dominance of small-sized taxa with epifaunal morphology strongly increased. This low-diversity fauna occurs in sediments with a reduced thorium/uranium ratio (proxy for oxygenation and kaolinite enrichment (proxy for high humidity. The faunal changes were thus caused by the combined effects of hypoxic and hyposaline conditions in a stratified water column, due to extreme warming with its accompanying intensified hydrologic cycle. The PETM acme coincides with the maximum flooding surface (MFS of the Gilsonryggen depositional sequence, composed of the Gilsonryggen Member and the overlying Battfjellet and Aspelintoppen formations. The transgressive phase of the sequence was initiated by local tectonics, while the eustatic sea-level rise of the PETM was superimposed on this transgression.To access the supplementary material for this article, please see supplementary files under Article Tools online.

  12. Significance of correspondence between river discharge and proloculus size of benthic foraminifera in paleomonsoonal studies

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.

    Variations in the mean proloculus size (MPS) of the benthic foraminiferal species Rotalidium annectens were studied in a core collected off Karwar (20 m water depth), on the west coast of India. Comparison of downcore variations in the MPS...

  13. Distribution of living planktonic foraminifera in the coastal upwelling region of Kenya, Africa

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Paulinose, V.T.; Jayalakshmy, K.V.; Panikkar, B.M.; Kutty, M.K.

    met with in waters near the equator. The faunal characteristics as related to hydrology and the role of some ecological parameters like temperature and salinity have been delineated.The evidence obtained from statistical analysis of the data of most...

  14. Living planktonic foraminifera during the late summer monsoon period in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Mohan, R.; Muralinath, A.S.

    Globigerinoides ruber@@ and @iG. sacculifer@@ are the most abundant species, while the ecologically most important species @iGlobigerina bulloides@@ is very rare. The low abundance of @iG. bulloides@@ can be explained by the warming of the surface water in combination...

  15. Measuring past changes in ENSO variance using Mg/Ca measurements on individual planktic foraminifera

    Science.gov (United States)

    Marchitto, T. M.; Grist, H. R.; van Geen, A.

    2013-12-01

    Previous work in Soledad Basin, located off Baja California Sur in the eastern subtropical Pacific, supports a La Niña-like mean-state response to enhanced radiative forcing at both orbital and millennial (solar) timescales during the Holocene. Mg/Ca measurements on the planktic foraminifer Globigerina bulloides indicate cooling when insolation is higher, consistent with an ';ocean dynamical thermostat' response that shoals the thermocline and cools the surface in the eastern tropical Pacific. Some, but not all, numerical models simulate reduced ENSO variance (less frequent and/or less intense events) when the Pacific is driven into a La Niña-like mean state by radiative forcing. Hypothetically the question of ENSO variance can be examined by measuring individual planktic foraminiferal tests from within a sample interval. Koutavas et al. (2006) used d18O on single specimens of Globigerinoides ruber from the eastern equatorial Pacific to demonstrate a 50% reduction in variance at ~6 ka compared to ~2 ka, consistent with the sense of the model predictions at the orbital scale. Here we adapt this approach to Mg/Ca and apply it to the millennial-scale question. We present Mg/Ca measured on single specimens of G. bulloides (cold season) and G. ruber (warm season) from three time slices in Soledad Basin: the 20th century, the warm interval (and solar low) at 9.3 ka, and the cold interval (and solar high) at 9.8 ka. Each interval is uniformly sampled over a ~100-yr (~10-cm or more) window to ensure that our variance estimate is not biased by decadal-scale stochastic variability. Theoretically we can distinguish between changing ENSO variability and changing seasonality: a reduction in ENSO variance would result in narrowing of both the G. bulloides and G. ruber temperature distributions without necessarily changing the distance between their two medians; while a reduction in seasonality would cause the two species' distributions to move closer together.

  16. Revalidation of the genus Chiloguembelitria Hofker: Implications for the evolution of early Danian planktonic foraminifera

    Science.gov (United States)

    Arenillas, Ignacio; Arz, José A.; Gilabert, Vicente

    2017-10-01

    Guembelitria is the only planktonic foraminiferal genus whose survival from the mass extinction event of the Cretaceous/Paleogene (K/Pg) boundary has been clearly proven. The evolution of Guembelitria after the K/Pg boundary led to the appearance of two guembelitriid lineages in the early Danian: one biserial, represented by Woodringina and culminating in Chiloguembelina, and the other trochospiral, represented by Trochoguembelitria and culminating in Globoconusa. We have re-examined the genus Chiloguembelitria, another guembelitriid descended from Guembelitria and whose taxonomic validity had been questioned, it being considered a junior synonym of the latter. Nevertheless, Chiloguembelitria differs from Guembelitria mainly in the wall texture (pustulate to rugose vs. pore-mounded) and the position of the aperture (umbilical-extraumbilical to extraumbilical vs. umbilical). Chiloguembelitria shares its wall texture with Trochoguembelitria and some of the earliest specimens of Woodringina, suggesting that it played an important role in the evolution of early Danian guembelitriids, as it seems to be the most immediate ancestor of both trochospiral and biserial lineages. Morphological and morphostatistical analyses of Chiloguembelitria discriminate at least five species: Chg. danica, Chg. irregularis, and three new species: Chg. hofkeri, Chg. trilobata and Chg. biseriata.

  17. Living benthonic foraminifera in a tidal environment: Gulf of Khambhat (India)

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    of the study area is a high energy environment, it is deep and it is bounded by a narrow, long shallow (at a submerged depth of 7-20 m) sand bar (Eastern Bank) which rises from 40-43 m depth and is separated from the coast by the parallel Sutherland Channel...

  18. Relationship between benthic foraminifera and sediment in the estuarine complex of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.

    of similarity between assemblages was related to the similarity of sediments at different stations. The changes in species composition appeared to correspond most clearly with differences in the clay content of the sediment...

  19. Planktonic foraminifera – Geochemical variability, eddies and seasonality in the Mozambique Channel

    NARCIS (Netherlands)

    Steinhardt, J.

    2015-01-01

    Ocean circulation is generally considered as one of the main players in the climate system. How certain ocean current systems have varied over time has a profound impact on climateand also the future climate is expected to be strongly affected by changes in ocean circulation. Specific parts of the

  20. New data on Upper Devonian stratigraphy of the northwestern Kuznetsk basin: Evidence from foraminifera and chondrichthyes

    Science.gov (United States)

    Timokhina, I. G.; Rodina, O. A.

    2015-09-01

    The thorough investigation of four Frasnian-Famennian (Upper Devonian) boundary sections along the right side of the Tom River northwest of Kemerovo yielded new data on the composition of their foraminiferal and ichthyofaunal assemblages. These data were used for development of the zonal foraminiferal scale for Upper Devonian deposits of the northwestern Kuznetsk coal basin and the first zonal scale for their subdivision on the basis of Elasmobranchii remains and for correlation of the examined sections between each other and with Upper Devonian sequences in other regions. The analysis of foraminiferal and ichthyofaunal assemblages, which are the most widespread in upper Frasnian sections of the northwestern Kuznetsk coal basin, made it possible to specify the regional stratigraphic model.

  1. Zoogeography of the bottom Foraminifera of the West-African coast

    Directory of Open Access Journals (Sweden)

    V. Mikhalevich

    2008-03-01

    Full Text Available The sediment samples from the continental shelf of West-Equatorial Africa (from the Strait of Gibraltar to the Niger estuary, depths ranging from 0 to 69 m were found to contain 176 bottom foraminiferal species. For the majority of them (126 species, their areas of occurrences were mapped and the peculiar features of the geographical range and distribution were studied. The species natural habitats were established based on the taxonomical revision of the species in study all over the World Ocean based on the collections of the Zoological Institute RAS and wide literary data. The method of perforated cards was used to mark the geographical locations of all of the species studied. In order to establish the species geographic zonal distribution (together with their depth habitat the five characteristic groups of the species were separated: 1. pan-oceanic (cosmopolitan, 2. widely spread tropical-boreal, 3. tropical-law boreal, 4. tropical-subtropical, 5. tropical. The percent of the species of each group among the species composition was established for the fauna of each station and for the whole region.

  2. Biology of Pelosina arborescens PEARCEY, 1914, with comparative notes on Astrorhiza limicola SANDAHL, 1857 (Foraminifera: Astrorhizidae)

    DEFF Research Database (Denmark)

    Cedhagen, Tomas

    1993-01-01

    The diagnosis of Pelosina arborescens Pearcey, 1914 is amended: only the Scottish specimens of the original description are now included in the species. Factors like water current, aquarium conditions, bioturbation and rough sampling and handling may cause a wide morphological variation which ear...

  3. Proloculus size variation in Recent benthic foraminifera: Implications for paleoclimatic studies

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Rao, A.S.

    , mean proloculus size is useful; a higher ratio means more microspheric forms and thus a lower mean size of the proloculus. To test this possibility, the mean proloculus size of Cavarotalia annectens was measured in 14 surface sediment samples from...

  4. Addressing environmental issues through foraminifera - Case studies from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    stream_size 9 stream_content_type text/plain stream_name Int_Workshop_IGCP-514_42.pdf.txt stream_source_info Int_Workshop_IGCP-514_42.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  5. The intriguing relationship between coiling direction and reproductive mode in benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Rao, A.S.

    -1147. BROOKS, A.L. 1967. Standing crop, vertical distribution, and morhometrics of Ammonia beccarii (Linne') Limnol. Ocea nogr.l2:667-684. CARLAP, M. 1987. Deep sea circulation in the northeasternAtlan- tic over the past 30,000 years: the benthic...

  6. Some aberrant foraminifera from the shelf sediments of central east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A; Almeida, F.

    A rich foraminiferal outer shelf assemblage has yielded some aberrant forms in the case of @iUvigerina@@ sp. @iSiphonoperta@@ sp., and @iNodosaria@@ sp. The aberration is (1) in the development of two terminal apertures with parallel necks...

  7. Benthic foraminifera as pollution indices in the marine environment of west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Nigam, R.

    Two ecosystems affected by acidic pollutants (Thana Creek, Bombay and inshore area of Trivandrum, Kerala) and two other ecosystems affected by alkaline pollutants (Cola Bay, Goa and inshore area of Karwar, Karnataka) were studied for pollution...

  8. The relative sensitivity of benthonic foraminifera in the polluted marine environment of Cola Bay, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    The foraminiferal gradient in the bay indicates high foraminiferal productivity with large sized, mostly megalospheric, robust, many-chambered @iAmmonia@@, with @iElphidium@@ sp., @iFlorilus boenum, F. scaphus@@ followed by miliolids in the littoral...

  9. Foraminifera [Marine Microfossil] as an additional tool for archaeologists - Examples from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    as dockyard. 3- possible use of stones as weight to ZiJl wafer for irrigation and thus irrigafiorz tank; [CI Foramin- $era e~~countered in rite sediments indicating the presence of marine water in rec~angular body rh~ts stippor~ing dockyard; [Dl salr... and sedi- ment deposired ,nust have brackish wafer farrru in sediment and [B] Poor rain fall conditions and sedinrent deposited must have marine water fauna. A core sattrples cml yield paleomonsoonal history. GLIMPSES OF MARINE ARCHAEOLOGY IN INDIA...

  10. Laboratory experiment to record rate of movement of cultured benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Khare, N.; Nigam, R.

    for the Rate of Movement of Quinqueloculina sp. Date Position in Figure 1.10* 20.2.95 a b (Sp.A) c d Figure e I f gh Time 1.15 1.45 2.15 2.30 2.45 3.00 3.15 3.30 Total No. of observations = 8 1.10* 21.2.95 a b (Sp.A) c d Figure e 11 f gh 1.30 2.00 2....15 2.30 2.45 3.00 3.15 3.30 Total No. of observations = 8 1.15* 22.2.95 a b (Sp.A) c d Figure e III f gh i j 1.20 1.50 2.15 2.30 2.45 3.00 3.15 3.30 3.45 4.00 Total No. of observations = 10 2.55* 22.2.95 a b (Sp.B) c d Figure e IV f g 3.00 3...

  11. Effect of salinity induced pH/alkalinity changes on benthic foraminifera: A laboratory culture experiment

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Kouthanker, M.; Kurtarkar, S.R.; Nigam, R.; Naqvi, S.W.A.; Linshy, V.N.

    attaining a certain growth (Fig. 4). Further progress of experiment resulted in the death of 20% specimen at 30 psu and 35 psu salinity while ~13% specimens died at 40 psu and 25 psu salinity (Fig. 8). It was observed that, after 40 days of attaining... the desired salinity of 20 psu, the specimens turned opaque and subsequently ~7% specimens died at 20 psu salinity. All the specimens (100%) kept at 10 psu salinity died within 45 days while all those at 15 psu died within 63 days. The death of the specimens...

  12. 70 kD stress protein (Hsp70) analysis in living shallow-water benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Heinz, P.; Marten, R.A.; Linshy, V.N.; Haap, T.; Geslin, E.; Kohler, H-R.

    ) the monoclonal antibody “mouse anti-human Hsp70 (MA3-006)”; Dianova, Hamburg, Germany, dilution 1:5000, or, alternatively, (b) the monoclonal antibody “mouse anti-chicken Hsp70/Hsc70 (SPA-822)”; Dianova, dilution 1:1000 (experiment II), or (c) a combination... antibody solution (goat anti-mouse IgG coupled to peroxidase, Dianova, dilution 1:1000 in 10% horse serum in TBS) for 2 h at room temperature. After subsequent TBS washing, the antibody complex was detected by the staining solution (1 mM 4-chloro(1...

  13. Non-lethal effects of ocean acidification on two symbiont-bearing benthic foraminiferal species

    Directory of Open Access Journals (Sweden)

    A. McIntyre-Wressnig

    2011-09-01

    Full Text Available We conducted experiments to assess the effect of elevated atmospheric carbon dioxide concentrations on survival, fitness, shell microfabric and growth of two species of symbiont-bearing coral-reef benthic foraminifera, using pCO2 Ievels similar to those likely to occur in shallow marine pore waters in the decades ahead. Foraminifera were cultured at constant temperature and controlled pCO2 (385 ppmv, 1000 ppmv, and 2000 ppmv for six weeks, and total alkalinity and dissolved inorganic carbon were measured to characterize the carbonate chemistry of the incubations. Foraminiferal survival and cellular energy levels were assessed using Adenosine Triphosphate (ATP analyses, and test microstructure and growth were evaluated using high resolution SEM and image analysis. Fitness and survival of Amphistegina (A. gibbosa and Archaias (A. angulatus were not directly affected by elevated pCO2 and the concomitant decrease in pH and calcite saturation states (Ωc values of the seawater (pH and Ωc values of 8.12, 7.86, and 7.50, and 5.4, 3.4, and 1.5, for control, 1000 ppmv, and 2000 ppmv, respectively. In A. gibbosa, a species precipitating low-Mg calcite, test growth was not affected by elevated pCO2, but areas of dissolved calcium carbonate were observed even though Ωc was >1 in all treatments; the fraction of test area dissolved increased with decreasing Ωc. Similar dissolution was observed in offspring produced in the 2000 ppmv pCO2 treatments. In A. angulatus, whose tests are more-solubile high-Mg calcite, growth was greatly diminished in the 2000 ppmv pCO2 treatment compared to the control. These non-lethal effects of ocean acidification – reduced growth in A. angulatus, and enhanced dissolution in A. gibbosa – may reflect differences in test mineralogy

  14. Non-lethal effects of ocean acidification on two symbiont-bearing benthic foraminiferal species

    Science.gov (United States)

    McIntyre-Wressnig, A.; Bernhard, J. M.; McCorkle, D. C.; Hallock, P.

    2011-09-01

    We conducted experiments to assess the effect of elevated atmospheric carbon dioxide concentrations on survival, fitness, shell microfabric and growth of two species of symbiont-bearing coral-reef benthic foraminifera, using pCO2 Ievels similar to those likely to occur in shallow marine pore waters in the decades ahead. Foraminifera were cultured at constant temperature and controlled pCO2 (385 ppmv, 1000 ppmv, and 2000 ppmv) for six weeks, and total alkalinity and dissolved inorganic carbon were measured to characterize the carbonate chemistry of the incubations. Foraminiferal survival and cellular energy levels were assessed using Adenosine Triphosphate (ATP) analyses, and test microstructure and growth were evaluated using high resolution SEM and image analysis. Fitness and survival of Amphistegina (A.) gibbosa and Archaias (A.) angulatus were not directly affected by elevated pCO2 and the concomitant decrease in pH and calcite saturation states (Ωc values) of the seawater (pH and Ωc values of 8.12, 7.86, and 7.50, and 5.4, 3.4, and 1.5, for control, 1000 ppmv, and 2000 ppmv, respectively). In A. gibbosa, a species precipitating low-Mg calcite, test growth was not affected by elevated pCO2, but areas of dissolved calcium carbonate were observed even though Ωc was >1 in all treatments; the fraction of test area dissolved increased with decreasing Ωc. Similar dissolution was observed in offspring produced in the 2000 ppmv pCO2 treatments. In A. angulatus, whose tests are more-solubile high-Mg calcite, growth was greatly diminished in the 2000 ppmv pCO2 treatment compared to the control. These non-lethal effects of ocean acidification - reduced growth in A. angulatus, and enhanced dissolution in A. gibbosa - may reflect differences in test mineralogy for the two species; the long-term ecological consequences of these effects are not yet known.

  15. Middle Cretaceous to Oligocene rise of the Middle American landbridge - documented by south-eastwards younging shallow water carbonates

    Science.gov (United States)

    Baumgartner-Mora, Claudia; Baumgartner, Peter O.; Barat, Flore

    2013-04-01

    -Nicoya fault line (Central Costa Rica) Late Cretaceous oceanic plateaus may represent actual outcrops of the trailing edge of the Caribbean Large Igneous Province (CLIP). These include the SE corner of the Herradura Promontory (Costa Rica) and the Azuero Plateau cropping out in Coiba, Sona and Azuero (Panama). CLIP formation triggered a new, E-dipping subduction zone and Campanian-Maastrichtian arc initiation on the CLIP edge. By middle to late Eocene times this Middle American Arc and forearc areas reached the photic zone leading to widespread formation of carbonate banks/ramps. They are dated by many Larger Foraminifera of the genera Amphistegina, Asterocyclina, Discocyclina, Euconoloides, Eofabiania, Fabiania, Gypsina, Helicolepidina, Heterostegina, , Lepidocyclina, Linderina, Neodiscocyclina, Nummulites, Operculina, Orthophragmina, Polylepidina, Proporocyclina, and Sphareogypsina. The first shallow carbonates that encroach on arc/forearc basements in Panama are dated as Late Eocene in Azuero and the Canal Basin and as Oligocene, dated by Lepidocyclina miraflorensis, L. giraudi, L. canellei around the Chucunaque Basin of Eastern Panama. Progressive shallowing of the trailing edge of the Caribbean plate from NW (middle/Late Cretaceous) to SE (Late Eocene-Oligocene) implies a growing restriction of the Atlantic - Caribbean - Pacific seaway that must have affected global circulation patterns, to be considered in palaeo-oceanographic/palaeo-climatic models of the Late Cretaceous -Tertiary.

  16. Additions to the annotated list of marine alien biota in the Mediterranean with special emphasis on Foraminifera and Parasites

    Directory of Open Access Journals (Sweden)

    A. ZENETOS

    2008-05-01

    Full Text Available The present work is an update of the annotated list (ZENETOS et al., 2006 based on literature up to April 2008. Emphasis is given to ecofunctional/taxonomic groups poorly addressed in the annotated list, such as the foraminiferan and parasites, while macrophytes are critically reviewed following the CIESM Atlas (VERLAQUE et al., in press. Moreover, in this update the bio-geographic area addressed includes the Sea of Marmara. The update yields a further 175 alien species in the Mediterranean bringing the total to 903. As evidenced by recent findings, more and more previously known ‘casual’ aliens, are becoming established. Approximately 100 more species have become well established in the region, raising the number of established species to 496 versus 385 until 2005. In the period from January 2006 to April 2008 more than 80 published papers have resulted in the recording of 94 new aliens, which is interpreted as a new introduction every 9 days, a rate beyond the worst scenario.

  17. Benthic foraminifera at the Paleocene/Eocene thermal maximum in the western Tethys (Forada section): variability in climate and productivity

    Science.gov (United States)

    Giusberti, L.; Boscolo Galazzo, F.; Thomas, E.

    2015-09-01

    The Forada section (northeastern Italy) provides a continuous, expanded deep-sea record of the Paleocene/Eocene thermal maximum (PETM) in the central-western Tethys. We combine a new, high resolution, benthic foraminiferal assemblage record with published calcareous plankton, mineralogical and biomarker data to document climatic and environmental changes across the PETM, highlighting the benthic foraminiferal extinction event (BEE). The onset of the PETM, occurring ~ 30 kyr after a precursor event, is marked by a thin, black, barren clay layer, possibly representing a brief pulse of anoxia and carbonate dissolution. The BEE occurred within the 10 cm interval including this layer. During the first 3.5 kyr of the PETM several agglutinated recolonizing taxa show rapid species turnover, indicating a highly unstable, CaCO3-corrosive environment. Calcareous taxa reappeared after this interval, and the next ~ 9 kyr were characterized by rapid alternation of peaks in abundance of various calcareous and agglutinant recolonizers. These observations suggest that synergistic stressors including deep water CaCO3-corrosiveness, low oxygenation, and high environmental instability caused the extinction. Combined faunal and biomarker data (BIT index, higher plant n-alkane average chain length) and the high abundance of the mineral chlorite suggest that erosion and weathering increased strongly at the onset of the PETM, due to an overall wet climate with invigorated hydrological cycle, which led to storm flood-events carrying massive sediment discharge into the Belluno Basin. This interval was followed by the core of the PETM, characterized by four precessionally paced cycles in CaCO3%, hematite%, δ13C, abundant occurrence of opportunistic benthic foraminiferal taxa, as well as calcareous nannofossil and planktonic foraminiferal taxa typical of high productivity environments, radiolarians, and lower δDn-alkanes. We interpret these cycles as reflecting alternation between an overall arid climate, characterized by strong winds and intense upwelling, with an overall humid climate, with abundant rains and high sediment delivery (including refractory organic carbon) from land. Precessionally paced marl-limestone couplets occur throughout the recovery interval of the CIE and up to ten meters above it, suggesting that these wet-dry cycles persisted, though at declining intensity, after the peak PETM. Enhanced climate extremes at mid-latitudes might have been a direct response to the massive CO2 input in the ocean atmosphere system at the Paleocene-Eocene transition, and may have had a primary role in restoring the Earth system to steady state.

  18. A note on the occurrence of the encrusting foraminifera Homotrema rubrum in reef sediments from two distinctive hydrodynamic settings

    Directory of Open Access Journals (Sweden)

    MACHADO ALTAIR J.

    2002-01-01

    Full Text Available Sediment samples from two different reef environments were analyzed for their foraminiferal content: the Sioba/Rio do Fogo reefs, located in a broad shallow shelf dominated by strong currents (Rio Grande do Norte State, and the Praia do Forte reefs, located in a narrow shelf under the influence of wind-induced waves (Bahia State. The recorded foraminiferal fauna, from forty-six samples, is represented by 113 species, being the encrusting species Homotrema rubrum present in nine samples from the Sioba/Rio do Fogo reefs and in 11 samples from Praia do Forte reefs. Homotrema fragments recovered from Sioba/Rio do Fogo are mostly polished with rounded edges (51.59% and some have a whitish color, whereas the specimens from Praia do Forte reefs are predominantly composed of reddish fragments (82.41% with sharpened points (63.88%. The high wave energy on the reef environment of Praia do Forte is responsible for the fragmentation of living Homotrema tests (red color, which are deposited near to their source area. The effects of the strong current system operating in the broad continental shelf of Sioba/Rio do Fogo is the major cause of sediment reworking, producing polished grains accumulated in its reef surroundings.

  19. Distribution and morphological abnormalities of recent foraminifera in the Marano and Grado Lagoon (North Adriatic Sea, Italy

    Directory of Open Access Journals (Sweden)

    R. MELIS

    2013-07-01

    Full Text Available The Marano and Grado Lagoon, is a northern Adriatic wetland system of relevant naturalistic and economic value, that is constantly under quality control in accordance with the current environmental directives. Benthic foraminifers community with its morphological abnormalities were investigated in the recent sediments (about 10 years old of 21 stations collected in the framework of the “MIRACLE” Project which aimed at testing the coexistence of clam farming with high Hg contamination. Euryhaline foraminifers, well known in Mediterranean brackish-waters, mainly characterizes the total assemblage. A. tepida dominates in areas characterized by low salinity, high clay and Corg content, but also to anthropogenic pressure. E. gunteri and H. germanica are recorded in the western sector of the lagoon, which is more affected by salinity variations and agricultural activities. Slightly higher values of assemblage diversity appear in less restricted areas of the lagoon or, at least, where physical parameters such as temperature and salinity are less variable. The test abnormalities, carried out on total assemblage, shows that the FAI (Foraminiferal Abnormality Index values always exceed 1% of the total assemblage, with clear decreasing gradients from inland to the sea (from N to S and from W to E in the studied area.

  20. Anatomy of a shoreface sand ridge revisited using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf

    Science.gov (United States)

    Robinson, M.M.; McBride, R.A.

    2008-01-01

    Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf ???5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

  1. Anatomy of a shoreface sand ridge revisted using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf

    Science.gov (United States)

    Robinson, Marci M.; McBride, Randolph A.

    2008-01-01

    Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf not, vert, ~5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

  2. Foraminifera isotopic records... with special attention to high northern latitudes and the impact of sea-ice distillation processes

    Energy Technology Data Exchange (ETDEWEB)

    Hillaire-Marcel, Claude, E-mail: hillaire-marcel.claude@uqam.ca [GEOTOP, Universite du Quebec a Montreal, PO Box 8888, succursale ' centre ville' Montreal, Qc, H3C 3P8 (Canada)

    2011-05-15

    Since the reassessment of oxygen isotope paleotemperatures by N. Shackleton in the late 60s, most papers using isotopic records from planktic or benthic foraminifers imply a direct relationship between oxygen isotopes in seawater and the ice/ocean volume, thus some linkage with salinity, sea level, etc. Such assumptions are also made when incorporating 'isotopic modules' in coupled models. Here, we will further examine the linkages between salinity and oxygen isotope ratios of sea-water recorded by foraminifers, and their potential temporal and spatial variability, especially in the northern North Atlantic and the Arctic oceans. If temporal and spatial changes in the isotopic composition of precipitations and ice meltwaters tune the isotopic properties of the fresh water end-member that dilutes the ocean, rates of sea-ice formation and evaporation at the ocean surface play a further role on the salt and oxygen isotope contents of water masses. Thus, the oxygen 18-salinity relationship carries a specific isotopic signature for any given water mass. At the ocean scale, residence time and mixing of these water masses, as well as the time dependent-achievement of proxy-tracer equilibrium, will also result in variable recordings of mass transfers into the hydrosphere, notable between ice-sheets and ocean. Since these records in water mass may vary in both amplitude and time, direct correlations of isotopic records will potentially be misleading. Implications of such issues on the interpretation of oxygen isotope records from the sub-arctic seas will be discussed, as well as the inherent flaws of such records due to sedimentological and or ecological parameters.

  3. Response of shallow water benthic foraminifera to a 13C-labeled food pulse in the laboratory

    Digital Repository Service at National Institute of Oceanography (India)

    Linshy, V.N.; Nigam, R.; Heinz, P.

    reservoir (Berger et al. 1989). Therefore, ocean productivity changes play an important role in providing feedback to climatic changes. In the oceans, primary production is carried out by marine microscopic algae, which use sunlight as an energy source...

  4. Growing need to study foraminifera in the laboratory culture experiments: An attempt from the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.; Koli, N.Y.

    culture programme is studied. Initially, the effect of different media (like plain sea water and Erdschreiber medium), food and antibiotic drug on the growth of foraminiferal tests are monitored. The results suggest that Erdschreiber medium is condusive...

  5. Evolution of subpolar North Atlantic surface circulation since the early Holocene inferred from planktic foraminifera faunal and stable isotope records

    DEFF Research Database (Denmark)

    Staines-Urias, Francisca; Kuijpers, Antoon; Korte, Christoph

    2013-01-01

    of the Faroe Islands, are located in the transitional area where surface waters of subpolar and subtropical origin mix before entering the Arctic Mediterranean. In these areas, large-amplitude millennial variability in the characteristics of the upper-water column appears modulated by changes in the intensity...

  6. A first look at past sea surface temperatures in the equatorial Indian Ocean from Mg/Ca in foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Nigam, R.; Weldeab, S.; Mackensen, A.; Naidu, P.D.

    Ocean SST was approx. 2.1 degrees C colder during the last glacial maximum as compared to present times. The data further shows that the surface equatorial Indian Ocean was comparatively warmer during isotopic stage 5e than at present (approx. 29.9 vs...

  7. Seasonal variation in the flux of planktic foraminifera: Sediment trap results from the Bay of Bengal, Northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S; Curry, W.B.; Ittekkot, V.; Muralinath, A.S

    stream_size 15 stream_content_type text/plain stream_name J_Foramin_Res_27_5.pdf.txt stream_source_info J_Foramin_Res_27_5.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  8. Living (stained) benthic foraminifera from the Mozambique Channel (eastern Africa): Exploring ecology of deep-sea unicellular meiofauna

    Science.gov (United States)

    Fontanier, C.; Garnier, E.; Brandily, C.; Dennielou, B.; Bichon, S.; Gayet, N.; Eugene, T.; Rovere, M.; Grémare, A.; Deflandre, B.

    2016-09-01

    Live (Rose-Bengal stained) deep-sea foraminiferal faunas have been studied at four stations between 530 and 3200-m depth in the Mozambique Channel (eastern Africa) to understand how complex environmental conditions (e.g., organic matter, oxygenation) control their ecological structure (i.e., diversity, density, and microhabitats). Two upper-slope stations, located at 530- and 780-m depth off Madagascar, are bathed by well-oxygenated bottom waters. They are characterized by fine sediments enriched in highly degraded organic matter (low amino-acid bio-availability and reduced chlorophyllic freshness). Mineralization of organic compounds results in relatively moderate oxygen penetration depth (i.e., 15 and 30 mm) in sediment. Interestingly, foraminiferal species richness (S) is exceptionally high at both sites. The highest densities are observed in the 780-m deep station, where peculiar sedimentary facies of organic matter are recorded (OC >2.0% DW). Redox conditions and sedimentary organic matter control the composition and the vertical distribution (i.e. microhabitat) of benthic faunas at both upper-slope sites. Bolivina alata, Bulimina marginata, Haplophragmoides bradyi and Nouria compressa are relevant bio-indicators of enhanced burial of organic matter prevailing at the 780-m deep station (i.e., eutrophic conditions), whereas Uvigerina hispida and Uvigerina semiornata are dominant at the 530-m deep station (i.e., relatively mesotrophic conditions). Two other stations are located on well-ventilated terraces from the deep-sea canyons of Tsiribihina and Zambezi (>3000-m depth). They are characterized by carbonate ooze, which is depleted in degraded organic matter and, where oxygen penetration depth is relatively deep (i.e.,>80 mm). Because of food scarcity, S and densities are relatively low, and agglutinated and organic-walled taxa dominate foraminiferal faunas. Hospitella fulva, a foraminiferal species belonging to Allogromiida, occupies very deep infaunal microhabitat, what disrupts the classical scheme of microhabitat patterns in oligotrophic settings.

  9. Diversity of benthic foraminifera of the shelf and slope of the NE-Atlantic: analysis of datasets

    OpenAIRE

    Dorst, Sabine; Schönfeld, Joachim

    2013-01-01

    The objective of this work was to review the distribution of benthic foraminiferal species at the western European continental margin from 43–58uN, determine their diversity, and generate a standardized taxonomy based on 44 publications (1913–2010) and unpublished information. Qualitative and quantitative data based upon foraminiferal occurrences and species abundances were included together with supplementary sedimentological and hydrographical data. From the species inventory, as well as f...

  10. Benthic foraminifera of bathyal hydrocarbon vents of the Gulf of Mexico: Initial report on communities and stable isotopes

    Science.gov (United States)

    Sen Gupta, Barun K.; Aharon, Paul

    1994-06-01

    Substrates associated with active hydrocarbon vents in bathyal Gulf of Mexico support numerous foraminiferal species, with a few of them showing unusually high relative abundances. In the 584- to 695-m-depth range,Bolivina ordinaria, Gavelinopsis translucens, andCassidulina neocarinata strongly dominate the vent community, whereasBolivina subaenariensis andUvigerina laevis play this role around a vent at 216 m water depth. The bathymetric imprint on the foraminiferal record is also seen in theδ 18O compositions of some species, includingUvigerina peregrina. The adaptation of foraminiferal communities to bacterial (Beggiatoa) mats, in which the redox boundary is very close to the sediment—water interface, and anomalous depletions of13C inU. peregrina (relative to the same species from nonventing sites) indicate that several species are probably facultative anaerobes and tolerant of H2S toxicity.

  11. Seasonal variability in the surface sediments of Mobile Bay, Alabama, recorded by geochemistry and foraminifera, 2009–2010

    Science.gov (United States)

    Umberger, D.K.; Osterman, L.E.; Smith, C.G.; Frazier, J.; Richwine, K.A.

    2012-01-01

    A study was undertaken in order to document and quantify recent environmental change in Mobile Bay, Alabama. The study was part of the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility project, a regional project funded by the Coastal and Marine Geology Program to understand how natural forcings and anthropogenic modifications influence coastal ecosystems and their susceptibility to coastal hazards. Mobile Bay is a large drowned-river estuary that has been modified significantly by humans to accommodate the Port of Mobile. Examples include repeated dredging of a large shipping channel down the central axis of the bay and construction of a causeway across the head of the bay and at the foot of the bayhead delta. In addition to modifications, the bay is also known to have episodic periods of low oxygen (hypoxia) that result in significant mortality to fish and benthic organisms (May, 1973). For this study a series of surface sediment samples were collected. Surface benthic foraminiferal and bulk geochemical data provide the modern baseline conditions of the bay and can be used as a reference to changing environmental parameters in the past (Osterman and Smith, in press) and into the future. This report archives data collected as part of the Mobile Bay Study that may be used in future environmental change studies.

  12. Description of Larger Benthic Foraminifera Species from the Bartonian of Yakacık-Memlik Region (N Ankara, Central Turkey)

    OpenAIRE

    DEVECİLER, Ali

    2014-01-01

    A. callosa Hottinger, A. fragilis Hottinger, A. fusiformis Sowerby, A. kieli Sirel & Acar, A. nuttalli (Davies), A. stercusmuris Mayer-Eymar and nummulitid species Nummulites malatyensis Sirel are described and figured from the shallow-water marine limestone samples of Yakacık-Memlik region (N-Ankara, Central Turkey). Amongst all these species the presence of A. fragilis, A. fusiformis and N. malatyensis represents the Bartonian stage in the studied area. In addition, stratigraphic range of A...

  13. Coastal lagoon sediments and benthic foraminifera as indicator for Holocene sea-level change: Samsø, southern Kattegat

    DEFF Research Database (Denmark)

    Sander, Lasse; Morigi, Caterina; Pejrup, Morten

    relative sea-level to drop. Originally, two Pleistocene elevations existed as separated islands, which were high enough to reach above sea-level during the transgressions. Proceeding coastal erosion produced material that was transported longshore and that was successively accommodated in a shallow sound....... Over time, an extensive beach ridge system formed, which eventually connected the islands, giving Samsø its characteristic shape. Ephemeral shallow-water lagoons evolved in topographic depressions along the shores of the island, most of which became inactive until today. A semi-enclosed coastal lagoon...... remained in the NE part of the island, which developed around an archipelago of submerged moraine hills. In the scope of this project we will study the evolution of the coastal landscape from the mid-Holocene to present day. We use a multi-proxy approach to resolve local variations in sea...

  14. Effect of temperature and salinity on stable isotopic composition of shallow water benthic foraminifera: A laboratory culture study

    Digital Repository Service at National Institute of Oceanography (India)

    Kurtarkar, S.R.; Linshy, V.N.; Saraswat, R.; Nigam, R.

    in the laboratory. In the present work, shallow water benthic foraminiferal species, Rosalina sp. and Pararotalia nipponica were subjected to different combinations of seawater temperature (25�C to 35�C) and salinity (25 psu to 37 psu) in the laboratory to assess...

  15. Evolution and variation of the Tsushima warm current during the late Quaternary: Evidence from planktonic foraminifera, oxygen and carbon isotopes

    Institute of Scientific and Technical Information of China (English)

    LI TieGang; SUN RongTao; ZHANG DeYu; LIU ZhenXia; LI Qing; JIANG Bo

    2007-01-01

    The evolution and variation history of the Tsushima warm current during the late Quaternary was reconstructed based on the quantitative census data of planktonic foraminiferal fauna, together with oxygen and carbon isotope records of mixed layer dweller G ruber and thermocline dweller N. dutertrei in piston core CSH1 and core DGKS9603 collected separately from the Tsushima warm current and the Kuroshio dominated area. The result showed that the Tsushima warm current vanished in the Iowstand period during 40-24 cai ka BP, while the Kuroshio still flowed across the Okinawa Trough, arousing strong upwelling in the northern Trough. Meanwhile, the influence of freshwater greatly increased in the northern Okinawa Trough, as the broad East China Sea continental shelf emerged. The freshwater reached its maximum during the last glacial maximum (LGM), when the upwelling obviously weakened for the lowest sea-level and the depression of the Kuroshio. The modern Tsushima warm current began its development since 16 cai ka BP, and the impact of the Kuroshio increased in the middle and northern Okinawa Trough synchronously during the deglaciation and gradually evolved as the main water source of the Tsushima current. The modern Tsushima current finally formed at about 8.5 cai ka BP,since then the circulation structure has been relatively stable. The water of the modern Tsushima current primarily came from the Kuroshio axis. A short-term wiggle of the current occurred at about 3 cai ka BP, probably for the influences from the enhancement of the winter monsoon and the depression of the Kuroshio. The cold water masses greatly strengthened during the wiggle.

  16. Seasonal flux and assemblage composition of planktic foraminifera from the northern Gulf of Mexico, 2008–14

    Science.gov (United States)

    Reynolds, Caitlin E.; Richey, Julie N.

    2016-07-28

    The U.S. Geological Survey anchored a sediment trap in the northern Gulf of Mexico in January 2008 to collect seasonal time-series data on the flux and assemblage composition of live planktic foraminifers. This report provides an update of the previous time-series data to include continuous results from January 2013 through May 2014. Ten taxa constituted ~95 percent of both the 2013 and 2014 assemblages: Globigerinoides ruber (pink and white varieties), Globigerinoides sacculifer, Globigerina calida, Globigerinella aequilateralis, Globorotalia menardii group [The Gt. menardii group includes Gt. menardii, Gt. tumida, and Gt. ungulata], Orbulina universa, Globorotalia truncatulinoides, Pulleniatina spp., and Neogloboquadrina dutertrei. In 2013, the mean daily flux was 177 tests per square meter per day (m−2 day−1), with maximum fluxes of >1,200 tests m−2 day−1 during the middle of February and minimum fluxes of 900 tests m−2 day−1 at the end of January and minimum fluxes of <30 tests m−2 day−1 at the beginning of January. Globorotalia truncatulinoides showed a clear preference for the winter, consistent with data from 2008 to 2012. Globigerinoides ruber (white) flux data for 2012 (average 23 tests m−2 day−1) were consistent with data from 2011 (average 30 tests m−2 day−1) and 2010 (average 29 tests m−2 day−1) and showed a steady threefold increase since 2009 (average 11 tests m−2 day−1) and a tenfold increase from the 2008 flux (3 tests m−2 day−1). The flux data from 2013 (average 15 tests m−2 day−1) and 2014 (average 8 tests m−2 day−1) showed decline from the previous 3 years.

  17. Bacteria and Foraminifera: key players in a short-term deep-sea benthic response to phytodetritus

    NARCIS (Netherlands)

    Moodley, L.; Middelburg, J.J.; Boschker, H.T.S.; Duineveld, G.; Pel, R.; Herman, P.M.J.; Heip, C.H.R.

    2002-01-01

    The deep-sea floor has long been considered a 'food desert' but recent observations suggest that episodic inputs of relatively fresh organic matter (phytodetritus) occur and that benthic processing of this material may be rapid. Although the responses of the total community in terms of oxygen consum

  18. Benthic Foraminifera as bio-indicators of anthropogenic impacts in coastal environments: Acqua dei Corsari area case study (Palermo, Italy).

    Science.gov (United States)

    Musco, Marianna; Cuttitta, Angela; Bicchi, Erica; Quinci, Enza Maria; Sprovieri, Mario; Tranchida, Giorgio; Giaramita, Luigi; Traina, Anna; Salvagio Manta, Daniela; Gherardi, Serena; Mercurio, Pietro; Siragusa, Angelo; Mazzola, Salvatore

    2017-04-15

    This study investigates living benthic foraminiferal assemblages as bio-indicators of anthropogenic activities in a coastal area within the Gulf of Palermo (Sicily, Italy), affected by industrial and urban activities, and evaluates the environmental quality through the calibration of a Tolerant Species index (%TSstd). Sediments from 6 stations were sampled along a bathymetric transect from the coast to offshore. Sediment grain size, TOC, major, minor and trace elements and polycyclic aromatic hydrocarbons (PAHs) were compared to benthic foraminiferal assemblages and species at each station. Diversity and density of benthic foraminiferal assemblages were not affected by the presence of pollutants, while tolerant species increased with organic (TOC and PAHs) or chemical (As and Pb) concentrations. Moreover, the calibration of the %TSstd formula to >125μm foraminiferal assemblage, gives a detailed description of environmental quality along the transect, representing a good and sensitive tool to evaluate marine coastal environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Additions to the annotated list of marine alien biota in the Mediterranean with special emphasis on Foraminifera and Parasites

    Directory of Open Access Journals (Sweden)

    A. ZENETOS

    2012-12-01

    Full Text Available The present work is an update of the annotated list (ZENETOS et al., 2006 based on literature up to April 2008. Emphasis is given to ecofunctional/taxonomic groups poorly addressed in the annotated list, such as the foraminiferan and parasites, while macrophytes are critically reviewed following the CIESM Atlas (VERLAQUE et al., in press. Moreover, in this update the bio-geographic area addressed includes the Sea of Marmara.The update yields a further 175 alien species in the Mediterranean bringing the total to 903. As evidenced by recent findings, more and more previously known ‘casual’ aliens, are becoming established. Approximately 100 more species have become well established in the region, raising the number of established species to 496 versus 385 until 2005. In the period from January 2006 to April 2008 more than 80 published papers have resulted in the recording of 94 new aliens, which is interpreted as a new introduction every 9 days, a rate beyond the worst scenario.

  20. Deep-sea foraminifera from the Cassidaigne Canyon (NW Mediterranean): Assessing the environmental impact of bauxite red mud disposal

    NARCIS (Netherlands)

    Fontanier, C.; Fabri, M.-C.; Buscail, R.; Biscara, L.; Koho, K.A.; Reichart, G.-J.; Cossa, D.; Galaup, S.; Chabaud, G.; Pigot, L.

    2012-01-01

    Benthic foraminiferal assemblages were investigated from two sites along the axis of the Cassidaigne Canyon (NW Mediterranean Sea). Both areas are contaminated by bauxite red mud enriched in iron, titanium, vanadium and chromium. These elemental enrichments are related to bauxite-derived minerals an

  1. Ostracoda and Foraminifera associated with macrofauna of marginal marine origin in continental sabkha sediments of Tayma (NW Saudi Arabia)

    Science.gov (United States)

    Pint, Anna; Frenzel, Peter; Engel, Max; Plessen, Birgit; Melzer, Sandra; Brückner, Helmut

    2016-04-01

    The oasis Tayma in northwestern Saudi Arabia (27°38'N, 38°33'E) is well known for its rich archaeological heritage and also hosts a key sedimentary record of Holocene environmental change.The palaeontologically investigated material comes from two 5.5 m long sediment cores taken in the northeastern and central part of the sabkha and two outcrops of shoreline deposits at the northeastern and southwestern margin of a large lake. Microfossil-rich layers have an age of about 9.2-ca. 8 ka BP. The sandy and carbonate-dominated sediments contain autochthonous balanids, the gastropods Melanoides tuberculatus and hydrobiids as well as the foraminifers Ammonia tepida (Cushman, 1926), Quinqueloculina seminula (Linnaeus, 1758), and Flintionoides labiosa (d'Orbigny, 1839). This brackish water association is completed by partially mass-occurrence of Cyprideis torosa (JONES, 1850), an euryhaline and generally widely tolerant ostracod species. Only the smooth shelled morphotype littoralis occurs. The association indicates a large brackish water lake with temporary freshwater inflows. All species documented originate in the marginal marine environment of the Red or Mediterranean Sea within the intertidal zone and hence they are adapted for strong environmental changes. We assume negative water balance under arid climatic conditions as cause for the high salinity of this athalassic lake. Sieve-pore analyses and shell chemistry suppose a trend of increasing salinity towards the top of the studied microfossil-bearing sections. This pattern is confirmed by increasing test malformation ratios of foraminifers. The marine origin of the fauna is surprising in this area 250 km away from the sea in an altitude of about 800 m a.s.l. We assume an avian-mediated transport of eggs, larvae or even adult animals to this site. The brackish water character of the lake enabled a permanent settling of marginal marine foraminifers, ostracods and even macrofauna as gastropods and balanids. The studied microfauna, morphological and shell chemistry analyses reveal the athalassic but saline character of the palaeo-lake and indicate a more humid climate phase in the early Holocene of northwestern Saudi Arabia. Furthermore, the increasing salinity at the younger part of the sections confirms a climatic shift to drier conditions during the mid-Holocene. This study is a contribution to the research project "CLEAR - Holocene CLimatic Events of Northern ARabia" (https://clear2018.wordpress.com/).

  2. Evolution and variation of the Tsushima warm current during the late Quaternary: Evidence from planktonic foraminifera, oxygen and carbon isotopes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The evolution and variation history of the Tsushima warm current during the late Quaternary was reconstructed based on the quantitative census data of planktonic foraminiferal fauna, together with oxygen and carbon isotope records of mixed layer dweller G. ruber and thermocline dweller N. dutertrei in piston core CSH1 and core DGKS9603 collected separately from the Tsushima warm current and the Kuroshio dominated area. The result showed that the Tsushima warm current vanished in the lowstand period during 40―24 cal ka BP, while the Kuroshio still flowed across the Okinawa Trough, arousing strong upwelling in the northern Trough. Meanwhile, the influence of freshwater greatly increased in the northern Okinawa Trough, as the broad East China Sea continental shelf emerged. The freshwater reached its maximum during the last glacial maximum (LGM), when the upwelling obviously weakened for the lowest sea-level and the depression of the Kuroshio. The modern Tsushima warm current began its development since 16 cal ka BP, and the impact of the Kuroshio increased in the middle and north- ern Okinawa Trough synchronously during the deglaciation and gradually evolved as the main water source of the Tsushima current. The modern Tsushima current finally formed at about 8.5 cal ka BP, since then the circulation structure has been relatively stable. The water of the modern Tsushima cur- rent primarily came from the Kuroshio axis. A short-term wiggle of the current occurred at about 3 cal ka BP, probably for the influences from the enhancement of the winter monsoon and the depression of the Kuroshio. The cold water masses greatly strengthened during the wiggle.

  3. Regional variations in the fluxes of foraminifera carbonate, coccolithophorid carbonate and biogenic opal in the northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Gaye, B.

    NE Fig. 10. Pie diagrams showing the relative fluxes of diatom-opal, coccolithoph material during the southwest (SW) and northeast (NE) monsoon period. CBBT EIOT WAST SW NE SW NE argued that in the presence of iron, derived from aeolian dust...

  4. Deep-sea foraminifera from the Cassidaigne Canyon (NW Mediterranean): Assessing the environmental impact of bauxite red mud disposal

    NARCIS (Netherlands)

    Fontanier, C.; Fabri, M.-C.; Buscail, R.; Biscara, L.; Koho, K.A.; Reichart, G.-J.; Cossa, D.; Galaup, S.; Chabaud, G.; Pigot, L.

    2012-01-01

    Benthic foraminiferal assemblages were investigated from two sites along the axis of the Cassidaigne Canyon (NW Mediterranean Sea). Both areas are contaminated by bauxite red mud enriched in iron, titanium, vanadium and chromium. These elemental enrichments are related to bauxite-derived

  5. Late Pleistocene glacial-interglacial shell-size-isotope variability in planktonic foraminifera as a function of local hydrography

    Science.gov (United States)

    Metcalfe, B.; Feldmeijer, W.; de Vringer-Picon, M.; Brummer, G.-J. A.; Peeters, F. J. C.; Ganssen, G. M.

    2015-08-01

    So-called "vital effects" are a collective term for a suite of physiologically and metabolically induced variability in oxygen (δ18O) and carbon (δ13C) isotope ratios of planktonic foraminifer shells that hamper precise quantitative reconstruction of past ocean parameters. Correction for potential isotopic offsets from equilibrium or the expected value is paramount, as too is the ability to define a comparable life stage for each species that allows for direct comparison. Past research has focused upon finding a specific size range for individual species in lieu of other identifiable features, thus allowing ocean parameters from a particular constant (i.e. a specific depth or season) to be reconstructed. Single-shell isotope analysis of fossil shells from a mid-latitude North Atlantic Ocean piston core covering Termination III (200 to 250 ka) highlight the advantage of using a dynamic size range, i.e. utilising measurements from multiple narrow sieve size fractions spanning a large range of total body sizes, in studies of palaeoclimate. Using this methodology, we show that isotopic offsets between specimens in successive size fractions of Globorotalia inflata and Globorotalia truncatulinoides are not constant over time, contrary to previous findings. For δ18O in smaller-sized globorotalids (212-250 μm) it is suggested that the offset from other size fractions may reflect a shallower habitat in an early ontogenetic stage. A reduction in the difference between small and large specimens of G. inflata between insolation minima and maxima is interpreted to relate to a prolonged period of reduced water column stratification. For the shallow-dwelling species Globigerina bulloides, no size-isotope difference between size fractions is observed, and the variability in the oxygen isotopic values is shown to correlate well with the seasonal insolation patterns. As such, patterns in oxygen isotope variability of fossil populations may be used to reconstruct past seasonality changes.

  6. Late Pleistocene Glacial-Interglacial related shell size isotope variability in planktonic foraminifera as a function of local hydrology

    Science.gov (United States)

    Metcalfe, B.; Feldmeijer, W.; de Vringer-Picon, M.; Brummer, G.-J. A.; Peeters, F. J. C.; Ganssen, G. M.

    2015-01-01

    So called "vital effects", a collective noun for a suite of physiological and metabolic induced variability, in oxygen (δ18O) and carbon (δ13C) isotope ratios of planktonic foraminifer shells hamper precise quantitative reconstruction of past ocean parameters. Correction for potential isotopic offsets from the equilibrium or the expected value is paramount, as too is the ability to define a comparable life-stage for each species that allows for direct comparison. Past research has focused upon finding a specific size range for individual species in lieu of other identifiable features, that allow ocean parameters from a particular constant (i.e. a specific depth or season) to be reconstructed. Single shell isotope analysis of fossil shells from a mid-latitude North Atlantic Ocean piston-core covering Termination III (200 to 250 kyr) highlight the advantage of using a dynamic size range in studies of palaeoclimate. Using this methodology, we show that isotopic offsets between specimens in successive size fractions of G. inflata and G. truncatulinoides are not constant over time, contrary to previous findings. For δ18O in smaller sized globorotalids it is suggested that the offset from other size fractions may reflect a shallower habitat in an early ontogenetic stage. A reduction in the difference between small and large specimens of G. inflata between insolation minima and maxima is interpreted to relate to a prolonged period of reduced water column stratification. For the shallow dwelling species G. bulloides no size isotope difference between size fractions is observed, and the variability in the oxygen isotopic values are shown to correlate well with the seasonal insolation patterns. As such, patterns in oxygen isotope variability of fossil populations may be used successfully for reconstruction of past seasonality changes.

  7. Environmental Quality Assessment of Bizerte Lagoon (Tunisia) Using Living Foraminifera Assemblages and a Multiproxy Approach: e0137250

    National Research Council Canada - National Science Library

    Maria Virgínia Alves Martins; Noureddine Zaaboub; Lotfi Aleya; Fabrizio Frontalini; Egberto Pereira; Paulo Miranda; Miguel Mane; Fernando Rocha; Lazaro Laut; Monia El Bour

    2015-01-01

      This study investigated the environmental quality of the Bizerte Lagoon (Tunisia) through an integrated approach that combined environmental, biogeochemical, and living benthic foraminiferal analyses...

  8. Carbon and oxygen isotope time series records of planktonic and benthic foraminifera from the Arabian Sea: Implications on upwelling processes

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Niitsuma, N.

    .D. Naidu, N. Niitsuma/Palaeogeography, Palaeoclimatology, Palaeoecology 202 (2003) 85^9588 was not driven by calci¢cation temperature changes for the following reasons: (1) upwelling was stronger during this period (Prell and Kutz- bach, 1987; Naidu...

  9. Benthic foraminifera distribution in a tourist lagoon in Rio de Janeiro, Brazil: a response to anthropogenic impacts.

    Science.gov (United States)

    Vilela, Claudia Gutterres; Batista, Daniele Silva; Baptista Neto, José Antonio; Ghiselli, Renato Olindo

    2011-10-01

    Rodrigo de Freitas Lagoon, located in the Rio de Janeiro City, receives several types of polluted discharges. The knowledge of the sediment microfauna correlated with heavy metal and organic matter concentrations could supply important data about the conditions of the lagoon. The benthic foraminiferal assemblage presented larger diversity and more abundant samples in the lagoon entrance than in the inner area. The Ammonia tepida - Elphidium excavatum foraminiferal assemblage is characterized by dwarf, corroded and weak organisms. Agglutinated species were found only near the entrance. Low abundance values and sterility of five samples in the inner area (north/northeast) can be caused by high levels of heavy metals and organic matter. A. tepida shows negative correlation with increasing heavy metals values. PAHs and coprostanol high indexes, and the absence or low presence of microfauna in samples around the lagoon margin confirm illegal flows from gas stations and domestic sewage.

  10. Planktonic foraminifera as recorders of sea surface hydrography in the Eastern Tropical North Pacific (Gulf of Tehuantepec, MX)

    Science.gov (United States)

    Gibson, K.; Thunell, R.; Machain-Castillo, M. L.; Wejnert, K.; Nava-Fernández, X. A.; Rodriguez-Ramírez, A.; Tappa, E.

    2014-12-01

    The Gulf of Tehuanetpec (GoT) (14°-16°N and 92°-96°W) is located in the Eastern Tropical North Pacific, a region that is sensitive to changes in both Atlantic-Pacific water vapor transport as well as changes in ENSO. Within the ETNP, the GoT is unique in that it experiences significant changes in temperature (ΔT = 8-10°C) and salinity (ΔS = 3) associated with seasonal variations in precipitation and wind-driven upwelling. Establishing robust relationships between δ18O and Mg/Ca of foraminiferal calcite to sea surface temperature (SST) and sea surface salinity (SSS) in this region can then be used to study past changes in Atl-Pac water vapor transport and ENSO and how these relate to regional and global climate change. We present here a six year (2006-2012), weekly to biweekly resolved record of paired δ18O-Mg/Ca analyses of the planktonic foraminfer Globigerina bulloides, collected from a sediment trap mooring in the GoT (15° 38.826N, 95° 16.905 W). The G. bulloides δ18O values ranges from -0.14‰ to - 3.98‰, equivalent to ~16°C temperature, or nearly twice the observed instrumental change in SST. To help constrain the temperature influence on the δ18Ocalcite signal, Mg/Ca values were converted to temperature using previously published equations for G. bulloides. In addition, we calculated new equations using the Mg/Ca and satellite SST data. Depending on the calibration equation used, G. bulloides from the GoT show a ~5-8% change in Mg/Ca with temperature, and show generally good agreement with SST, particularly in winter upwelling months. The agreement between SST and Mg/Ca-based temperatures is less robust during the winter months of 2009, when a moderate El Niño year resulted in warmer and fresher surface conditions in the GoT than pervious and following years, indicating a deeper habitat depth for G. bulloides and perhaps reduced upwelling during El Niño conditions.

  11. Changes in the depth habitat of the Oligocene planktic foraminifera (Dentoglobigerina venezuelana) induced by thermocline deepening in the eastern equatorial Pacific

    Science.gov (United States)

    Matsui, Hiroki; Nishi, Hiroshi; Takashima, Reishi; Kuroyanagi, Azumi; Ikehara, Minoru; Takayanagi, Hideko; Iryu, Yasufumi

    2016-06-01

    Understanding planktic foraminiferal depth habitat along with consistent taxonomic concepts is key to accurate reconstruction of paleoceanographic records. The Oligocene-Pliocene long-ranging and widely distributed species Dentoglobigerina venezuelana lived in the mixed layer (shallower) during the early Oligocene, whereas the same species calcified at thermocline or subthermocline depths (deeper) during the late Oligocene and Miocene. The exact timing of the species' depth habitat change and its possible relationships with Oligocene climate dynamics remain unknown. Here we reveal isotopic records of D. venezuelana along with the Paragloborotalia siakensis group (a mixed-layer dweller) by using sediments at Integrated Ocean Drilling Program Site U1334 in the eastern equatorial Pacific throughout the Oligocene. A two-step depth habitat change of D. venezuelana is apparent: (1) from upper to lower mixed layer (~27.4 Ma) and (2) from lower mixed layer to thermocline depth (~26.3 Ma). In addition, the planktic foraminiferal faunal assemblage experienced a marked change from dominantly thermocline (deeper) species to abundant mixed-layer (shallower) species, suggesting that depth habitat shifts of D. venezuelana were clearly related to thermocline deepening in the eastern equatorial Pacific. Comparison of the first isotopic shift (~27.4 Ma) at multiple sites (U1334, U1333, and 1218) revealed a southward depth habitat change of D. venezuelana within ~200 kyr, implying overall thermocline deepening with reduced steepness in the eastern equatorial Pacific. We consider that global warming conditions during the late Oligocene likely caused thermocline deepening with upwelling decrease in the eastern equatorial Pacific, guiding D. venezuelana to adapt to greater depths in the water column.

  12. Bathymetric preference of four major genera of rectilinear benthic foraminifera within oxygen minimum zone in Arabian Sea off central west coast of India.

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumder, A.; Nigam, R.

    Congress, XXI Session (Copenhagen) 22 7–19. Bernhard J M 1992 Benthic foraminiferal distribution and biomass related to porewater oxygen content: Central California continental slope and rise; Deep-Sea Res. 39 585–605. Bernhard J M 1993 Experimental...

  13. Glacial-interglacial changes in the surface water characteristics of the Andaman Sea: Evidence from stable isotopic ratios of planktonic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Ahmad, S.M.; Patil, D.J.; Rao, P.S; Nath, B.N.; Rao, B.R.; Rajagopalan, G.

    Dryas cooling event and/or to a sudden decrease of fresh water influx from the Irrawady and Salween rivers into the Andaman Sea. High d13C values observed during the isotopic stages 2 and 4 are probably due to the enhanced productivity during...

  14. Spatial and temporal distribution of foraminifera in sediments off the central west coast of India and use of their test morphologies for the reconstruction of paleomonsoonal precipitation

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.

    and diversity. A total of 177 species have been identified and illustrated by scanning electron photo micrographs. Seventy-two genera, 47 families 26 super families and 5 sub orders are represented. In order to have insight into paleoclimatic changes...

  15. Monitoring heavy metal pollution in foraminifera from the Gulf of Edremit (northeastern Aegean Sea) between Izmir, Balıkesir and Çanakkale (Turkey)

    Science.gov (United States)

    Yümün, Zeki Ünal; Önce, Melike

    2017-06-01

    In this study, the populations and abnormal shell structures of Quaternary foraminifers in the sediments of the North-eastern Aegean Sea were examined. For this purpose, offshore drilling was carried out at three locations, and core samples were collected from 13 locations at Küçükkuyu (Çanakkale), Güre (Edremit-Balıkesir) and Dikili (İzmir). At these points, drilling reached depths ranging from 3.00 to 22.00 m beneath the seafloor; recent sediments were observed, but the bedrock was not reached. Examination of the faunal and sedimentological properties of the samples showed that the Gulf of Edremit is completely influenced by the sea and has rich foraminifers and ostracod populations. The abnormalities observed in the foraminifer shells, as well as the yellow- and/or black-coloured shells seen in both the foraminifer and ostracod populations, are due to natural and anthropogenic ecological pollution. The vertical (chronological) and horizontal (spatial) distributions of heavy metal concentrations in both the core and drill core samples were investigated to determine the causes of the morphological abnormalities observed in the foraminifers. In the present study, pollution index (PI) values were calculated to assess the degree of heavy metal pollution (Yümün 2017). The current land use status of the coastal areas corresponding to the measured PI values was investigated to identify the sources of the pollution. Especially in the Güre region, a large number of genera and species of benthic foraminifers showed overgrowth in the shell sizes of individuals, and the coloration of the shells is noteworthy. These changes in the shells are a result of thermal sources and agricultural activities in the region. Scanning electron microscopy (SEM) was used to perform an elemental analysis of the surfaces of dark yellow-orange foraminifers (Ammonia compacta and Elphidium crispum). The S, Fe and Mn concentrations in the shells were found to be high, based on the SEM analyses. This is similar to the high S and Fe contents of thermal waters. Thus, the main causes of the coloration of the shells have been accepted to be both thermal waters and fertilizers and pesticides that are used in agricultural activities.

  16. Rapid and massive carbon injections of the Early Paleogene: The carbonate and planktonic foraminifera records at ODP Site 1215 (Equatorial Pacific Ocean)

    Science.gov (United States)

    Leon Rodriguez, L.; Dickens, G. R.

    2010-12-01

    Models for ocean chemistry indicate that anthropogenic input of CO2 will decrease seawater pH and the concentration of carbonate ion. This should cause dissolution of pelagic carbonate on the seafloor and may reduce biogenic calcification. Stable carbon isotope records spanning the Late Paleocene and Early Eocene show a series of pronounced negative excursions (CIEs) interpreted as massive inputs of carbon. We therefore studied carbonate-rich sediments at Ocean Drilling Program (ODP) Site 1215, which were deposited on the flank of the East Pacific Rise from the Late Paleocene to Early Eocene, to track potential lysocline and ecological changes before, during and after the CIEs. We document four negative CIEs, which correlate to the PETM (Paleocene/Eocene Thermal Maximum, ~55.5 Ma), H1/ETM2 (~53.7 Ma), I1 (~53.2 Ma), and K/X (~52.5 Ma) events. These excursions are characterized by horizons of low carbonate content and an absence of planktonic foraminifers. Shortly after each perturbation, carbonate content and planktonic foraminifer abundance increased dramatically. We interpret these signals as representing time intervals when the lysocline and CCD initially shoaled because of massive carbon addition and subsequently deepened because of accelerated weathering and addition of alkalinity. We observe permanent ecological changes within the photic zone after the PETM. Globanomalinids (intermediate dwellers) more common in the record before the PETM locally disappeared afterwards. In contrast, acarinids and morozovellids (surface dwellers, photosymbont-bearing) were nearly absent before the PETM but become relatively abundant just after. Chiloguembelinids and “Tenuitellids” (intermediate dwellers) are more abundant between the H1/ETM2 and the I1 events, which could be an indication of enhanced carbonate preservation within the recovery phase of the lysocline or conditions that were more favorable for intermediate dwellers. Subbotinids and igorinids are rare in the record, either because of ecological reasons or because their susceptibility to dissolution. We conclude that the overall ecological conditions favored muricate taxa after the PETM, and that intermediate dwellers were only able to re-occupy their niche when waters cooled. The carbonate record at the ODP Site 1215 is complex but foraminiferal assemblage analyses allow us to distinguish carbonate dissolution and preservation during and following the postulated Early Eocene massive carbon injections as well as to show possible ecological changes within and after each event.

  17. A History of Warming Sea Surface Temperature and Ocean Acidification Recorded by Planktonic Foraminifera Geochemistry from the Santa Barbara Basin, California

    Science.gov (United States)

    Osborne, E.; Thunell, R.; Bizimis, M.; Buckley, W. P., Jr.; benitez-Nelson, C. R.; Chartier, C. J.

    2015-12-01

    The geochemistry of foraminiferal shells has been widely used to reconstruct past conditions of the ocean and climate. Since the onset of the Industrial Revolution, anthropogenically produced CO2 has resulted in an increase in global temperatures and a decline in the mean pH of the world's oceans. The California Current System is a particularly susceptible region to ocean acidification due to natural upwelling processes that also cause a reduction in seawater pH. The trace element concentration of magnesium and boron in planktonic foraminiferal shells are used here as proxies for temperature and carbonate ion concentration ([CO32-]), respectively. Newly developed calibrations relating Mg/Ca ratios to temperature (R2 0.91) and B/Ca ratios to [CO32-] (R2 0.84) for the surface-mixed layer species Globogerina bulloides were generated using material collected in the Santa Barbara Basin sediment trap time-series. Using these empirical relationships, temperature and [CO32-] are reconstructed using a 0.5 meter long multi-core collected within the basin. 210Pb activities were used to determine a sedimentation rate for the core to estimate ages for core samples (sedimentation rate: 0.341 cm/yr). A spike in 137Cs activity is used as a tie-point to the year 1965 coinciding with the peak of nuclear bomb testing. Our down-core record extends through the mid-19th century to create a history of rising sea surface temperatures and declining [CO32-] as a result of anthropogenic CO2 emissions.

  18. Mean proloculus size, delta super(13) C and delta super(18) O variations in recent benthic foraminifera from the west coast of India and their climatic implications

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Sarkar, A.

    The interrelationship between mean proloculus size (MPS), delta super(18) O and delta super(13) C vatiations in benthic foraminiferal species Rotalidium annectens and their relation with temperature (T) and salinity (S) have been studied in samples...

  19. Reconsideration of the so-called Oligocene fauna in the asphaltic deposits of Buton (Malay Archipelago) — 2. Young-Neogene Foraminifera and calcareous Algae

    NARCIS (Netherlands)

    Keyzer, F.G.

    1952-01-01

    Miopliocene marls from the island of Buton yield a large marine foraminiferal fauna and some calcareous algae. Three-hundred and thirthy-three species have been identified. Two genera, twenty-three species and four varieties are described as new. The existence of mud-volcanoes in young neogene time

  20. Shell anomalies observed in a population of Archaias angulatus (Foraminifera) from the Florida Keys (USA) sampled in 1982-83 and 2006-07

    Science.gov (United States)

    Souder, H.C.; McCloskey, B.; Hallock, P.; Byrne, R.

    2010-01-01

    Archived specimens of Archaias angulatus collected live at a depth of < 2. m in John Pennekamp Coral Reef State Park, Key Largo, Florida, in June, September and December 1982, and March 1983, were compared to specimens collected live from the same site and months in 2006-07. Shells were examined using light microscopy for anomalous features, which were then documented using scanning electron microscopy. Seven different types of morphological abnormalities and five different surface texture anomalies were observed. Physical abnormalities included profoundly deformed, curled, asymmetrical, and uncoiled shells, irregular suture lines, surface protrusions, and breakage/repair. Textural anomalies observed were surface pits, dissolution features, microborings, microbial biofilms, and the presence of epibionts including bryzoans, cyanobacteria and foraminifers. The same kinds of features were found in this A. angulatus population in both 1982-83 collections and 2006-07 collections. Within-date variability was higher in specimens collected in 1982-83, while between-date variability was higher in 2006-07; overall the range of variability was similar. Given that the site was originally chosen for study because these foraminifers were so abundant, the lack of significant change indicates that the variability of the geochemical habitat is still within the range that A. angulatus can thrive. ?? 2010.

  1. Younger Dryas and Holocene oceanography of the western Labrador Sea region based on foraminifera and sediment proxies from Placentia Bay, Newfoundland

    Science.gov (United States)

    Sheldon, Christina; Pearce, Christof; Seidenkrantz, Marit-Solveig; Kuijpers, Antoon; Reynisson, Njáll F.; Zilmer Christensen, Eva; Juncker Hansen, Mette

    2014-05-01

    Benthic foraminiferal assemblages and geochemical analyses from three marine sediment cores from Placentia Bay on the southwest coast of Newfoundland captured the evolving surface and subsurface environment of the eastern Labrador Sea during the late glacial and Holocene. The area, which is today located in the boundary zone between the Arctic Labrador current and the warm Gulf Stream in the eastern margin of the Labrador Sea was during the early part of the Younger Dryas (13.0-12.3 cal. kyr BP) dominated by cold, Arctic conditions and heavy sea-ice cover linked to a strong Polar Water component of the Inner Labrador Current. In the later part of the Younger Dryas (12.3-11.5 kyr BP) the influence of the Labrador Current (LC) became less pronounced resulting in more unstable conditions with varying sea-ice cover and increased influence of Gulf Stream water, presumably linked to an increased strength of the Atlantic Meridional Overturning Circulation (AMOC). The earliest Holocene (11.5-10.4 kyr BP) saw slightly warmer subsurface conditions in Placentia Bay and increased productivity, presumably caused by a decreased southward transport of Polar Water via the LC. The onset of a strong AMOC caused the northward movement of the frontal zone between the Subpolar Gyre and the North Atlantic Subtropical Gyre in the western North Atlantic region to closer proximity to the southern coast of Newfoundland compared to previously. From ca. 10.4-9.65 kyr BP increased bottom-current speeds and the presence of species often found in connection to oceanic fronts, suggest a further strengthening of the AMOC causing inflow of Atlantic-source water into Placentia Bay. This tendency was further strengthened at 9.65-7.3 kyr BP, which saw a relatively strong inflow of Atlantic-source Gulf Stream water into Placentia Bay, evidenced by high frequencies of Cassidulina neoteretis. This inflow of Atlantic was however temporarily halted around 8.2 kyr BP, when a short-lived, extreme peak in Globobulimina auriculata arctica suggests reduced bottom-water stratification. This may have been caused by an increased freshwater release from the Canadian Arctic, linked to the well-known 8.2-kyr event. Around 7.3 kyr BP, the inflow of warmer subsurface waters decreased, when subsurface waters of Placentia Bay returned to relatively cold, subarctic conditions. An enhanced influx of lower-saline water is inferred both by the presence of Elphidium bartletti, indicating an increased flux of meltwater from the Arctic entering Placentia Bay. This fresher water was likely transported by the Labrador Current and strong northerly winds. This scenario was again interrupted around ca 4.4 kyr BP, when higher C. neoteretis again suggest increase influx of Gulf Stream water, a tendency that continued until today, although with possibly slightly better mixing of LC and GS water after ~2.7 kyr BP. This decrease in the strength of the LC, may be linked to a decreased southward flow of LC water due to decreased meltwater release from the Canadian Arctic or due to a shift to a generally more negative Northern Annular Mode.

  2. Bathymetric preference of four major genera of rectilinear benthic foraminifera within oxygen minimum zone in Arabian Sea off central west coast of India

    Indian Academy of Sciences (India)

    Abhijit Mazumder; Rajiv Nigam

    2014-04-01

    Fifty two surface sediment samples collected from the region off Goa, central west coast of India from water depths of 15–3300 m were analyzed with special emphasis on foraminiferal content. Rectilinear benthic foraminiferal morphogroup shows a high relative abundance within Oxygen Minimum Zone (OMZ), both shallow marine (50–60 m water depth) and intermediate to deep water (150–1500 m water depth). We gave special emphasis on four rectilinear foraminiferal genera, namely Fursenkoina, Bolivina, Bulimina and Uvigerina to observe their individual distribution among OMZ. We found genus Fursenkoina predominates at the shallow water OMZ, within the water depth zone of 50–60 m. Within 150–1500 m water depth, which is considered as intermediate to deep water OMZ in this region, genus Uvigerina shows its highest abundance above 1000 m water depth, whereas genus Bulimina shows its affinity with deeper water environment (< 1000 m water depth). Genus Bolivina does not show any such depth preference, except its higher abundance in only intermediate to deep water OMZ. This depth differentiation among four rectilinear benthic foraminiferal genera presents the basic data for palaeoclimatic study based on the extent and intensity of OMZ along with the palaeobathymetry study.

  3. Ba/Ca in Planktonic Foraminifera as a Recorder of Freshwater Input to the Ocean: Proxy Refinement in the Gulf of Papua, Papua New Guinea

    Science.gov (United States)

    Gibson, K.

    2015-12-01

    In the study of paleoclimate, the past several decades have seen large strides in the advancement of proxies designed to reconstruct changes in sea surface temperature (SST); however, techniques for reconstructing ocean salinity are less well developed. The ratio of Ba/Ca in planktic foraminiferal tests has shown initial promise as a tool for reconstructing salinity in continental margin sites near river mouths. In these environments, Ba/Ca shows an inverse correlation with salinity, and often a less clear correlation to nutrients or indicators of productivity, as is more typical in open-ocean settings. An ideal area in which to apply and test foraminiferal Ba/Ca as a proxy for freshwater input is the Western Pacific Warm Pool (WPWP), where temperatures are relatively stable, but large variations in precipitation are today driven by the El Nino Southern Oscillation (ENSO) and strength of the Australian-Indonesian monsoon. Foraminiferal Ba/Ca in sediments proximal to a river mouth should therefore reflect changes in riverine input, which in turn reflect variations in precipitation on different timescales. We present here planktic foraminiferal δ18O, Ba/Ca, and Mg/Ca records spanning the last glacial-interglacial transition from marine sediment cores in the Gulf of Papua, located in the WPWP. The δ18O records show an increase in the magnitude of glacial-interglacial (G-IG) δ18O change (∆18O) moving away from the coastline and the mouth of the primary local freshwater source, the Fly River. The reduced amplitude in G-IG ∆18O in the cores closer to shore, manifested by more negative δ18O values before ~20 kyr ago, is likely due to freshwater input from the Fly River, with the effects diminishing with distance from the Fly River source. Temperature and sea level are also changing over the deglaciation, however, contributing to the signal recorded in the calcite δ18O. We use planktic Mg/Ca analyses and independent records of sea level change to isolate the component of foraminiferal δ18O that is due to salinity, which we then compare to the Ba/Ca records. With continued work toward proxy development, Ba/Ca has the potential to provide insight into past changes in precipitation in the WPWP in response to large or rapid climate change.

  4. Non-destructive foraminiferal paleoclimatic proxies: A brief insight

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.

    are used to infer key components of the past climate from the marine sediments. The fossil remains of marine microorganism foraminifera, are widely used to reconstruct past climate from marine archives, as foraminifera are highly abundant and extensively...

  5. Atypical delta sup(13) C signature in Globigerina bulloides at the ODP site 723A (Arabian Sea): Implications of environmental changes caused by upwelling

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Niitsuma, N.

    for nearly 10% of shell carbon. Therefore, the combination the foraminifera of faster calcification and involvement of respired CO sub(2) would induce more negative delta sup(13) C in G. bulloides compared to other foraminifera. Apart from vital effects...

  6. Sulfur in foraminiferal calcite as a potential proxy for seawater carbonate ion concentration

    Science.gov (United States)

    van Dijk, I.; de Nooijer, L. J.; Boer, W.; Reichart, G.-J.

    2017-07-01

    Sulfur (S) incorporation in foraminiferal shells is hypothesized to change with carbonate ion concentration [CO32-], due to substitution of sulfate for carbonate ions in the calcite crystal lattice. Hence S/Ca values of foraminiferal carbonate shells are expected to reflect sea water carbonate chemistry. To generate a proxy calibration linking the incorporation of S into foraminiferal calcite to carbonate chemistry, we cultured juvenile clones of the larger benthic species Amphistegina gibbosa and Sorites marginalis over a 350-1200 ppm range of pCO2 values, corresponding to a range in [CO32-] of 93 to 211 μmol/kg. We also investigated the potential effect of salinity on S incorporation by culturing juvenile Amphistegina lessonii over a large salinity gradient (25-45). Results show S/CaCALCITE is not impacted by salinity, but increases with increasing pCO2 (and thus decreasing [CO32-] and pH), indicating S incorporation may be used as a proxy for [CO32-]. Higher S incorporation in high-Mg species S. marginalis suggests a superimposed biomineralization effect on the incorporation of S. Microprobe imaging reveals co-occurring banding of Mg and S in Amphistegina lessonii, which is in line with a strong biological control and might explain higher S incorporation in high Mg species. Provided a species-specific calibration is available, foraminiferal S/Ca values might add a valuable new tool for reconstructing past ocean carbonate chemistry.

  7. Abrupt Climate Change in the Atlantic Ocean During the Last 20,000 Years: Insights from Multi-Element Analyses of Benthic and Planktic Foraminifera and a Coupled OA-GCM

    Science.gov (United States)

    2005-09-01

    waters. Benthic foraminiferal Cd/Ca from an intermediate depth Florida Current core documents the history of the northward penetration of southern...Kevin and Cindy, and Sara and Peter? Or without Toshi, the sushi chef at Misaki, who made my culinary life on Cape Cod tolerable? I owe many thanks to...present foraminiferal Cd/Ca and 813C data from an intermediate depth South Atlantic core in order to document the history of southern vs. northern

  8. Use of the Boron partition coefficient ‘KD’ and B/Ca from planktonic foraminifera in the estimation of past seawater pCO2

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.S.; Naidu, P.D.

    flux in the Arabian Sea. J. of Geophys. Res. 108(C8). 3255. doi:10.1029/2001JC001062. 9. Smith, H. J., Fischer, H., Wahlen, M., Mastroianni, D., and Deck, B. (1999) Dual modes of the carbon cycle since the Last Glacial Maximum. Nature. 400, 248...

  9. Middle Triassic (Anisian Limestones from Bled, Northwestern Slovenia: Microfacies and Microfossils

    Directory of Open Access Journals (Sweden)

    Erik Flügel

    1994-12-01

    Full Text Available Microfacies types (predominantly intrabioclastic grainstones and microfossils (predominantly dasycladacean algae and diverse foraminifera characterize the Anisian carbonates near Bled (Castle Hill and in the area westnorthwest of Bled as subtidal to intertidal shelf sediments deposited in the irmer part ofthe Julian carbonate platform. The age of the carbonates is Middle Anisian (Pelsonian according to the biozonation based on foraminifera and dasycladaceans.

  10. The foraminiferal - bacterial connection: an interdisciplinary study of meiofaunal behaviour in the deeper marine redox zone

    NARCIS (Netherlands)

    Langezaal, Alexandra Maria

    2003-01-01

    Foraminifera are unicellular organisms that are abundantly present in the marine realm. They inhabit both the water column as well as the sediment; these latter (benthic) foraminifera are the main subject of this thesis research. They have a high fossilisation potential, and for that reason they

  11. The foraminiferal - bacterial connection: an interdisciplinary study of meiofaunal behaviour in the deeper marine redox zone

    NARCIS (Netherlands)

    Langezaal, Alexandra Maria

    2003-01-01

    Foraminifera are unicellular organisms that are abundantly present in the marine realm. They inhabit both the water column as well as the sediment; these latter (benthic) foraminifera are the main subject of this thesis research. They have a high fossilisation potential, and for that reason they hav

  12. Delta ¹³C depleted oceans before the termination 2: More nutrient-rich deep-water formation or light-carbon transfer?

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.

    Carbon-isotopes (delta ¹³C) composition of benthic foraminifera has been extensively used to understand the link between deep-water circulation and climate. Equatorial Indian Ocean delta ¹³C records of planktic- and benthic-foraminifera together...

  13. Stable isotopic variations in foraminiferal test from Arabian Sea and its relation to the annual south-west monsoonal rainfall over the Indian subcontinent

    Digital Repository Service at National Institute of Oceanography (India)

    Borole, D.V.

    Examination of delta 18O estimations from the planktonic foraminifera, Globigerinoides ruber, collected at fortnightly intervals using deep sea sediment traps moored at depths of 1000 and 2787 m in the Eastern Arabian Sea (15 degrees 28'N and 68...

  14. Contrasting responses of coral reef fauna and foraminiferal assemblages to human influence in La Parguera, Puerto Rico

    Science.gov (United States)

    Coral reef biota including stony corals, sponges, gorgonians, fish, benthic macroinvertebrates and foraminifera were surveyed in coastal waters near La Parguera, in southwestern Puerto Rico. The goal was to evaluate sensitivity of coral reef biological indicators to human distur...

  15. Foraminiferal evidences for 77-year cycles of droughts in India and its possible modulation by the gleissberg solar cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.; Nair, R.R.

    foraminifera as proxy. These established parameters (indicating salinity fluctuations, thus runoff from rivers due to the monsoonal precipitation over catchment area) are an angular-asymmetrical morpho-group, directly proportional to salinity. The mean...

  16. Preliminary report on diatoms from the deep lake terraces, Vestfold Hills, Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Kellogg, D.E.; Kellogg, T.B.

    with fragments of pyroxenite, quartzite, permatite, gneiss, and glacial debris. Halite and mirabilite crystals are common. A general study of foraminifera of the lake sediments of the Vestfold Hills was made and the results are presented here...

  17. Life spans of planktonic foraminifers: New sight through sediment traps

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Saraswat, R.; Mazumder, A.

    Maastrichtian planktic foraminifera: LIFE SPANS OF PLANKTONIC FORAMINIFERS 133 methodological comparisons, intraspecific variability, and evidence for photosynthesis. Mar. Micropal. 36: 169-188. Kawahata, II., Nishimura, A. and Gagan, M.K. 2002. Seasonal...

  18. Cyclicity in the Late Holocene monsoonal changes from the western Bay of Bengal: Foraminiferal approach.

    Digital Repository Service at National Institute of Oceanography (India)

    Rana, S.S.; Nigam, R.

    of Paleogene aerobic/ anaerobic benthic foraminifera and deep sea circulation. Palaeogeography Palaeoclimatology Palaeoecology 83: 65-85. Lamy, F., Hebblin, D., Rohl, U., Wefer, G. 2001. Holocene rainfall variability in southern Chile: a marine record...

  19. Variability in calcitic Mg/Ca and Sr/Ca ratios in clones of the benthic foraminifer

    NARCIS (Netherlands)

    de Nooijer, L.J.; Hathorne, E.C.; Reichart, G.J.; Langer, G.; Bijma, J.

    2014-01-01

    Biological activity introduces variability in element incorporation during calcification and thereby decreases the precision and accuracy when using foraminifera as geochemical proxies in paleoceanography. This so-called 'vital effect' consists of organismal and environmental components. Whereas

  20. Microenvironments and anomalous benthic foraminiferal distribution within the neritic regime of the Dabhol-Vengurla sector (Arabian Sea)

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Nigam, R.

    An anomalous distribution of benthic Foraminifera within the neritic regime at a few stations indicates the existence of microenvironments. The vertical distribution is marked by the restricted occurrence of @iCibicides@@ group at only one station...