Salinity controls on Na incorporation in Red Sea planktonic foraminifera

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Mezger, E. M.; de 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.

Warming and surface ocean acidification over the last deglaciation: implications for foraminiferal assemblages

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Dyez, K. A.; Hoenisch, B.; deMenocal, P. B.

2017-12-01

Although plankton drift with ocean currents, their presence and relative abundance varies across latitudes and environmental seawater conditions (e.g. temperature, pH, salinity). While earlier studies have focused on temperature as the primary factor for determining the regional species composition of planktic foraminiferal communities, evidence has recently been presented that foraminiferal shell thickness varies with ocean pH, and it remains unclear whether ongoing ocean acidification will cause ecological shifts within this plankton group. The transition from the last glacial maximum (LGM; 19,000-23,000 years B.P.) to the late Holocene (0-5,000 years B.P.) was characterized by both warming and acidification of the surface ocean, and thus provides an opportunity to study ecosystem shifts in response to these environmental changes. Here we provide new δ11B, Mg/Ca, and δ18O measurements from a suite of global sediment cores spanning this time range. We use these geochemical data to reconstruct ocean temperature, pH and salinity and pair the new data with previously published analyses of planktic foraminifera assemblages to study the respective effects of ocean warming and acidification on the foraminiferal habitat. At most open-ocean sample locations, our proxies indicate warming and acidification similar to previously published estimates, but in some marginal seas and coastal locations pH changes little between over the glacial termination. At face value, these observations suggest that warming is generally more important for ecosystem changes than acidification, at least over the slow rates of warming and ocean acidification in this time period. While geochemical data collection is being completed, we aim to include these data in an ecological model of foraminiferal habitat preferences.

Holocene Millennial-scale Surface and Bottom Water Variability, Feni Drift, NE Atlantic Ocean: Foraminiferal Assemblages

Science.gov (United States)

Lassen, S. J.; Richter, T. O.; de Stigter, H. C.; van Weering, T. C. E.; de Haas, H.

A high-resolution sediment core from Feni Drift (ENAM9606, 56N 14W, 2543 m wa- ter depth) was investigated for planktonic and benthic foraminiferal assemblages dur- ing the last 12,000 years. During the Preboreal, peak abundances of T.quinqueloba indicate the passage of the Arctic front over the core site. Holocene planktonic foraminiferal assemblages indicate a gradual warming trend of surface water masses punctuated by a major cooling (8,200ky event s.l.), and possibly a slight cooling dur- ing the last 3,000 years. The interval from 10 to 5kyrs shows higher and fluctuating abundances of T.quinqueloba and G.bulloides, which suggest proximity of the subarc- tic front and enhanced spring blooms compared to the upper Holocene. Abundance peaks of N.pachyderma(s) and/or T.quinqueloba indicate a series of millennial-scale cooling events during the entire Holocene, which can be correlated to similar episodes previously described from other locations in the North Atlantic and Norwegian- Greenland Sea. Benthic foraminiferal assemblages indicate a gradual transition from seasonal, spring-bloom related food supply in the Lower Holocene (dominance of the phytodetritus species E.exigua) to possibly lower, but more sustained food supply in the Upper Holocene (dominance of C.obtusa and C.laevigata).

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. © 2015 John Wiley & Sons Ltd.

Forward Modeling of Carbonate Proxy Data from Planktonic Foraminifera using Oxygen Isotope Tracers in a Global Ocean Model

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Schmidt, Gavin A.

1999-01-01

The distribution and variation of oxygen isotopes in seawater are calculated using the Goddard Institute for Space Studies global ocean model. Simple ecological models are used to estimate the planktonic foraminiferal abundance as a function of depth, column temperature, season, light intensity, and density stratification. These models are combined to forward model isotopic signals recorded in calcareous ocean sediment. The sensitivity of the results to the changes in foraminiferal ecology, secondary calcification, and dissolution are also examined. Simulated present-day isotopic values for ecology relevant for multiple species compare well with core-top data. Hindcasts of sea surface temperature and salinity are made from time series of the modeled carbonate isotope values as the model climate changes. Paleoclimatic inferences from these carbonate isotope records are strongly affected by erroneous assumptions concerning the covariations of temperature, salinity, and delta (sup 18)O(sub w). Habitat-imposed biases are less important, although errors due to temperature-dependent abundances can be significant.

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

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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

Integrated foraminiferal biostratigraphy and chemostratigraphy of the querecual formation (Cretaceous), Eastern Venezuela

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Crespo De Cabrera, S.; Sliter, W.V.; Jarvis, I.

1999-01-01

An integrated foraminiferal biostratigraphy and chemostratigraphy is presented for the Lower to Upper Cretaceous Querecual Formation exposed on Chimana Grande Island, Eastern Venezuela. The formation consists of >450 m alternating foraminiferal and organic-rich carbonates and laminated mudrocks, and is considered the main hydrocarbon source rock for the eastern Venezuela Basin. Biostratigraphic resolution within the Querecual Formation is poor, due to a paucity of keeled planktonic foraminifera and impoverished benthic faunas. Deposition occurred in a bathyal environment, with dysaerobic or anoxic bottom waters resulting from high rates of surface productivity associated with an upwelling environment. Biostratigraphic evidence indicates that the Querecual Formation ranges from the upper Albian Rotalipora ticinensis Zone to the Santonian Dicarinella asymetrica Zone. Iron and Al contents fall through the Albian-Cenomanian indicating a progressive decrease in the detrital supply, driven by rising eustatic sea level. A Ca profile demonstrates variations in carbonate production and dissolution. High total organic carbon (TOC) intervals occur in the upper Albian to mid-Cenomanian and Turonian, and high Ba/Al and Si/Al ratios characterize mid-Cenomanian and younger sediments. Variations in these elements primarily reflect changes in marine productivity, but are also affected by diagenetic processes. A stable carbon isotope curve established from analysis of organic matter (??13Corg) correlates well with published ??13C curves for carbonates from England and Italy. The Cenomanian/Turonian boundary cannot be identified using planktonic foraminifera, because key taxa are absent, but the base of the Turonian is clearly indicated by a sharp fall in ??13C immediately above a major positive excursion. The bottom of the Coniacian is placed below a ??13C minimum, towards the base of the Dicarinella concavata Zone. Combined with the foraminiferal data, the isotopic data enable much

Low planktic foraminiferal diversity and abundance observed in a spring 2013 west-east Mediterranean Sea plankton tow transect

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Mallo, Miguel; Ziveri, Patrizia; Mortyn, P. Graham; Schiebel, Ralf; Grelaud, Michael

2017-05-01

Planktic foraminifera were collected with 150 µm BONGO nets from the upper 200 m water depth at 20 stations across the Mediterranean Sea between 2 May and 2 June 2013. The main aim is to characterize the species distribution and test the covariance between foraminiferal area density (ρA) and seawater carbonate chemistry in a biogeochemical gradient including ultraoligotrophic conditions. Average foraminifera abundances are 1.42 ± 1.43 ind. 10 m-3 (ranging from 0.11 to 5.20 ind. 10 m-3), including 12 morphospecies. Large differences in species assemblages and total abundances are observed between the different Mediterranean sub-basins, with an overall dominance of spinose, symbiont-bearing species indicating oligotrophic conditions. The highest values in absolute abundance are found in the Strait of Gibraltar and the Alboran Sea. The western basin is dominated by Globorotalia inflata and Globigerina bulloides at slightly lower standing stocks than in the eastern basin. In contrast, the planktic foraminiferal assemblage in the warmer, saltier, and more nutrient-limited eastern basin is dominated by Globigerinoides ruber (white). These new results, when combined with previous findings, suggest that temperature-induced surface water stratification and food availability are the main factors controlling foraminiferal distribution. In the oligotrophic and highly alkaline and supersaturated with respect to calcite and aragonite Mediterranean surface water, standing stocks and ρA of G. ruber (white) and G. bulloides are affected by both food availability and seawater carbonate chemistry. Rapid warming increased surface ocean stratification impacting food availability and changes in trophic conditions could be the causes of reduced foraminiferal abundance, diversity, and species-specific changes in planktic foraminiferal calcification.

Planktonic foraminiferal abnormalities in coastal and open marine eastern Mediterranean environments: A natural stress monitoring approach in recent and early Holocene marine systems

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Antonarakou, A.; Kontakiotis, G.; Zarkogiannis, S.; Mortyn, P. G.; Drinia, H.; Koskeridou, E.; Anastasakis, G.

2018-05-01

Marine environmental status can be assessed through the study of bio-indicator species. Here, we monitor natural environmental stress by the occurrence of morphologically abnormal planktonic foraminiferal specimens from a suite of surface sediments in the eastern Mediterranean Sea. We also compare Scanning Electron Microscopy (SEM) abnormality observations from sapropel S1-derived sediments in the Aegean, Libyan and Levantine basins, since they provide a direct record of a natural stress experiment that took place over past time scales. At initial sapropel deposition levels, we observe increased growth asymmetry in Globigerinoides ruber twinned and twisted individuals, possibly associated with eutrophication and anoxia. In modern material, a range of malformations and aberrant morphologies from slight deformity with smaller or overdeveloped chambers to more severe deformity with abnormally protruding or misplaced chambers, distorted spirals, and double tests is also observed, as a result of the hypersaline, oligotrophic and oxygen-depleted nature of the Mediterranean Sea water column. Overall, we highlight the current use of the relative abundance of abnormal tests as a bio-indicator for monitoring natural stress, especially the occurrence of twin specimens as indicative of high-salinity stress conditions, and further illustrate the necessity to map both their spatial and temporal distribution for accurate paleoenvironmental reconstructions. Such an approach presents the advantage to rapidly provide information over wide spatial and temporal scales, extending our ability to monitor a wide variety of environments (from coastal to the open-sea). However, further investigations should extend this approach to test the robustness of our findings in a number of similar oceanic settings.

The long way of planktonic Foraminifera from biostratigraphy to paleoceanography (Jean Baptiste Lamarck Medal Lecture)

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Premoli Silva, Isabella

2014-05-01

The mid of the last century was a time of flourishing studies concerning the importance of planktonic foraminifera in precisely dating and correlating sedimentary successions after the publication of the first biostratigraphic schemes provided by the Suisse Group (i.e. Kugler, Bolli, Broennimann) from the Caribbean region and former Southern USSR (Subbotina). Soon after Bolli's Trinidad scheme was widespread, planktonic foraminiferal distribution from Upper Cretaceous to Miocene was investigated intensively for dating the Neogene stratotypes, whose identifications were mainly based on poorly age-diagnostic, facies-controlled macrofossils, and for calibrating Paleogene larger foraminiferal distributions. Since these early works planktonic foraminiferal biostratigraphy was continously ameliorated, extended in time from Early Cretaceous to Recent by several authors and from different settings and domains, reaching progressively the current higher resolution, now calibrated to calcareous nannofossil distributions. To be mentioned, the detailed biostratigraphic studies on the Gubbio section (central Italy) provided (1) the first carefull documentation of the mass extinction of Cretaceous planktonic foraminifera, the presence of tiny Cretaceous survivors, and the rapid recovery of Danian assemblages, and (2) the first calibration of the Upper Cretaceous to Eocene reversal polarity scale in which the K/Pg boundary was demonstrated to fall within the magnetic reversal C29r. A major step forward was the recovery, since 1968, of several thousand of cores from over 1000 holes drilled in all oceans by the DSDP, ODP and IODP projects. The recovery of deep-sea sediments from all latitudes opened a new research field, the paleoceanography. Based on the large knowledge acquired on modern organisms in the '60s, for the Paleogene and Cretaceous reconstructions we started from the assumption that these extinct organisms lived in the water column like their modern counterpart and were

Size-dependent response of foraminiferal calcification to seawater carbonate chemistry

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Henehan, Michael J.; Evans, David; Shankle, Madison; Burke, Janet E.; Foster, Gavin L.; Anagnostou, Eleni; Chalk, Thomas B.; Stewart, Joseph A.; Alt, Claudia H. S.; Durrant, Joseph; Hull, Pincelli M.

2017-07-01

The response of the marine carbon cycle to changes in atmospheric CO2 concentrations will be determined, in part, by the relative response of calcifying and non-calcifying organisms to global change. Planktonic foraminifera are responsible for a quarter or more of global carbonate production, therefore understanding the sensitivity of calcification in these organisms to environmental change is critical. Despite this, there remains little consensus as to whether, or to what extent, chemical and physical factors affect foraminiferal calcification. To address this, we directly test the effect of multiple controls on calcification in culture experiments and core-top measurements of Globigerinoides ruber. We find that two factors, body size and the carbonate system, strongly influence calcification intensity in life, but that exposure to corrosive bottom waters can overprint this signal post mortem. Using a simple model for the addition of calcite through ontogeny, we show that variable body size between and within datasets could complicate studies that examine environmental controls on foraminiferal shell weight. In addition, we suggest that size could ultimately play a role in determining whether calcification will increase or decrease with acidification. Our models highlight that knowledge of the specific morphological and physiological mechanisms driving ontogenetic change in calcification in different species will be critical in predicting the response of foraminiferal calcification to future change in atmospheric pCO2.

The continuous plankton recorder survey: A long-term, basin-scale oceanic time series

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Gamble, John C.; Hunt, Harold G.

1992-01-01

In the 1920s, before the advent of echo sounders, fishery biologists were greatly concerned with assisting the fisherman to locate schools of pelagic fish. One of the approaches they developed was to relate the distribution of the planktonic food organisms to the presence of the schools of predators such as herring (Clupea harengus). The British planktologist, Alister Hardy, who had already carried out extensive studies on the feeding preferences of herring (Hardy, 1926a), initiated a program to examine the fishermen's contention that herring schools avoided 'green', i.e., phytoplankton-rich, water but could be correlated with high concentrations of zooplankton. This practical program was centered on the use of a specially developed instrument, the 'Plankton Indicator', designed to be used by the fisherman to assist in the search for suitable waters. It had limited success in its main aim but, as a collecting device, it embodied several profoundly important features. It was a simple instrument which was robust enough to be deployed and recovered by the crew of commercial vessels (in this case fishing vessels) while they were underway. The Indicator however, was no more than a high speed net which integrated the plankton over the area of sampling, but Hardy had also become interested in describing the patchiness of planktonic populations. He thus developed the Continuous Plankton Recorder (CPR) where he substituted the fixed filter screen of the Indicator by a continually moving length of silk mesh. The screen traversed at constant speed across the path of the incoming water and the trapped organisms were retained in place by sandwiching beneath an additional second mesh screen. Thus, knowing the speed of the towing vessel and the shooting and hauling positions, the spatial patterns of the plankton could be determined. Hardy took the first CPR to the Antarctic where he used it in the Southern Atlantic (Hardy, 1926b) and later deployed it in the North Sea to make

A correlation of Sr isotope stratigraphy and foraminiferal biostratigraphy in tertiary limestones of Papua New Guinea

International Nuclear Information System (INIS)

Allan, T.L.; Trotter, J.A.; Whitford, D.J.; Korsch, M.J.

2000-01-01

Strontium isotopic and stratigraphic data collected from the Darai Limestone of Papua New Guinea clearly demonstrate a systematic relationship between bulk 87 Sr/ 86 Sr ratio and index foraminiferal composition that closely reflects the relative stratigraphical range of the foraminifera in this region. A graphic correlation of stratigraphic, strontium isotopic and age ranges of the major index taxa permits direct evaluation of limestone age and isotopic composition in the Darai Limestone. The age of the Tf 1 /Tf 2 boundary (∼12.2 Ma) is significantly younger than the accepted estimate of ∼15.0 Ma (plankton Zone N9) and the Te/Tf boundary (∼20.3 Ma) is older than the generally accepted age of ∼l 8.5 Ma (plankton Zone N6)

Refinement of stratigraphy according to the first finds of planktonic species of Orbulina and Praeorbulina from the Guri Limestone of the Mishan Formation in northwest of Bandar Abbas, South Iran

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Daneshian, J.; Moallemi, S. A.; Derakhshani, M.

2016-05-01

The Zagros Basin is one of the most universal oil and gas basins that is located in the west to south of Iran and in north of the Arabian Plate. The Guri Member at the bottom of the Mishan Formation, in some areas such as Bandar Abbas hinterland, contains a significant amount of gas. The Bandar Abbas hinterland is located in the southeast of Zagros. The Guri Limestone is the youngest hydrocarbon reservoirs of the Zagros Sedimentary Basin. In this study, a total of 178 samples from the Guri Limestone in the Handun section are investigated for foraminiferal biostratigraphy. The study of foraminifers led to a recognition of 43 genera and 57 species of benthic and planktonic foraminifera. For the first time, planktonic foraminiferal species including Praeorbulina glomerosa, Praeorbulina transitoria, Orbulina suturalis, and Orbulina universa are reported, and based on the identified benthic and planktonic foraminifera taxa, the age of the Guri Member at Handun section is estimated as late Burdigalian to Langhian.

Foraminiferal biostratigraphy of Upper Cretaceous (Campanian - Maastrichtian) sequences in the Peri-Tethys basin; Moghan area, NW Iran

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Omidvar, Mahboobeh; Safari, Amrollah; Vaziri-Moghaddam, Hossain; Ghalavand, Hormoz

2018-04-01

The Upper Cretaceous sediments in the Moghan area, NW Iran, contain diverse planktonic and benthic foraminifera, with a total of 33 genera and 53 species (17 genera and 38 species of planktonic foraminifera and 16 genera and 15 species from benthic foraminifera), which led to the identification of six biozones spanning the middle Campanian to late Maastrichtian. A detailed paleontological study and biostratigraphic zonation of these sequences has been carried out in four surface sections. This study shows that there are two different facies in the Moghan area, based on the faunal content. A deep open marine condition exists in the Molok, Selenchai and Nasirkandi sections. In these sections, Upper Cretaceous sequences have diverse planktonic foraminiferal species including the Globotruncana ventricosa (middle to late Campanian), Globotruncanella havanensis (late Campanian), Globotruncana aegyptiaca (latest Campanian), Gansserina gansseri (latest Campanian to early Maastrichtian), Contusotruncana contusa- Racemiguembelina fructicosa (early to late Maastrichtian) and Abathomphalus mayaroensis (late Maastrichtian) zones. This deep open marine setting grades laterally into shallower marine condition dominated by large benthic foraminifera such as Orbitoides media, Orbitoides gruenbachensis, Orbitoides cf. apiculata, Lepidorbitoides minor, Pseudosiderolites sp., Siderolites praecalcitrapoides, Siderolites aff. calcitrapoides and Siderolites calcitrapoides. This facies is mainly recorded in the Hovay section. A detailed biostratigraphic zonation scheme is presented for the studied sections and correlated with the results of other studies in the Tethyan realm. This is the first biozonation scheme for Upper Cretaceous sequences of the Moghan area that can be used as a basis for ongoing studies in this area and other parts of Tethys basin.

The response of calcifying plankton to climate change in the Pliocene

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C. V. Davis

2013-09-01

Full Text Available As a result of anthropogenic pCO2 increases, future oceans are growing warmer and lower in pH and oxygen, conditions that are likely to impact planktic communities. Past intervals of elevated and changing pCO2 and temperatures can offer a glimpse into the response of marine calcifying plankton to changes in surface oceans under conditions similar to those projected for the future. Here we present new records of planktic foraminiferal and coccolith calcification (weight and size from Deep Sea Drilling Project Site 607 (mid-North Atlantic and Ocean Drilling Program Site 999 (Caribbean Sea from the Pliocene, the last time that pCO2 was similar to today, and extending through a global cooling event into the intensification of Northern Hemisphere glaciation (3.3 to 2.6 million years ago. Test weights of both surface-dwelling Foraminifera Globigerina bulloides and thermocline-dwelling Foraminifera Globorotalia puncticulata vary with a potential link to regional temperature variation in the North Atlantic, whereas in the tropics Globigerinoides ruber test weight remains stable. In contrast, reticulofenestrid coccoliths show a narrowing size range and a decline in the largest lith diameters over this interval. Our results suggest no major changes in plankton calcite production during the high pCO2 Pliocene or during the transition into an icehouse world.

An overview of the planktonic foraminiferal fauna in waters off the Kerala Coast, south-west India during summer

Digital Repository Service at National Institute of Oceanography (India)

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

the grouping (Q-mode analysis) of foraminiferal species into (1) rare and (2) dominant species, besides a few rare ones; this study indicates that dominant forms in the area can addapt to a wide range of environmental conditions. The same study with R...

Foraminiferal area density as a proxy for ocean acidification over the last 200 years in the California Current System

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Osborne, E.; Thunell, R.

2013-12-01

Anthropogenic activities have resulted in an increase in atmospheric CO2 from 280 ppm to 400 ppm over the last 250 years. It is estimated that approximately one-third of this anthropogenically produced CO2 is sequestered in the global ocean, increasing the inventory of bicarbonate (HCO3-) and hydrogen ions (H+) and consuming carbonate (CO32-) as a result of carbonate buffering reactions. This increase in [H+] lowers seawater pH, the phenomenon known as ocean acidification (OA). Estimates indicate that mean seawater pH has already decreased by 0.1 pH units since 1750 and IPCC reports indicate it is likely that CO2 concentrations will reach 790 ppm by 2100 further reducing pH by 0.3 units. Marine calcifiers, such as foraminifera, utilize CO32- dissolved in seawater during calcification, a process that is highly sensitive to changes in pH due to the chemical reactions described above. The reduction in surface ocean carbonate ion concentration ([CO32-]) caused by OA has impaired calcification of planktonic foraminifera and other marine calcifiers. It has been proposed that planktonic foraminiferal shell weight or shell thickness is positively correlated with ambient [CO32-] and has been used as proxy to reconstruct past changes in the surface ocean carbonate system. An ideal location for the application of this proxy is the California Current System (CSS), an Eastern Boundary Upwelling System (EBUS), which is characterized as having naturally lower pH. Upwelling introduces CO2-enriched bottom waters to the surface ocean, intensifying the effects of increasing dissolved CO2 as a result of anthropogenic activities. Upwelling produces a wide range of surface water [CO32-] making the Santa Barbara Basin (SBB) an ideal site to carry out a foraminiferal shell weight calibration study. Area density (ρA) is a new method for collecting size-normalized shell weights that will be used in this study. Species-specific calibrations have been derived for two symbiont

Non-destructive foraminiferal paleoclimatic proxies: A brief insight

Digital Repository Service at National Institute of Oceanography (India)

Saraswat, R.

include: 1. Total Foraminiferal Number 2. Benthic:Planktic Ratio 3. Foraminiferal Fragmentation index 4. Foraminiferal Size Fraction 5. Species Assemblages 6. Species Abundance 7. Test Size/Diameter 8. Coiling Direction 9. Average Number... to be corrected for the distance from the land by multiplying it by the square-root of its distance from the land (Berger and Diester-Haass, 1988). Foraminiferal Fragmentation Index The foraminiferal fragmentation index is defined as the number of fragments...

Planktonic Foraminifera Proxies Calibration Off the NW Iberian Margin: Nutrients Approach

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Salgueiro, E.; Castro, C. G.; Zuniga, D.; Martin, P. A.; Groeneveld, J.; de la Granda, F.; Villaceiros-Robineau, N.; Alonso-Perez, F.; Alberto, A.; Rodrigues, T.; Rufino, M. M.; Abrantes, F. F. G.; Voelker, A. H. L.

2014-12-01

Planktonic foraminifera (PF) shells preserved in marine sediments are a useful tool to reconstruct productivity conditions at different geological timescales. However, the accuracy of these paleoreconstructions depends on the data set and calibration quality. Several calibration works have been defining and improving the use of proxies for productivity and nutrient cycling parameters. Our contribution is centred on a multi-proxy calibration at a regional coastal upwelling system. To minimize the existing uncertainties affecting the use of trace elements and C stable isotopes as productivity proxy in the high productivity upwelling areas, we investigate the content and distribution of Ba/Ca and δ13C in the water column, its transference into the planktonic foraminifera shells, and, how the living planktonic foraminifera Ba/Ca and δ13C signal is related to the same planktonic foraminiferal species preserved in the sediment record. This study is based on a large data set from two stations (RAIA - 75m water depth, and CALIBERIA - 350m water depth) located off the NW Iberian margin (41.5-42.5ºN; 9-10ºW), and includes: i) two year monthly water column data (temperature, salinity, nutrients, chlorophyll a, Ba/Ca, and δ13C-DIC); ii) seasonal Ba/Ca, δ13C in several living PF species at both stations; and iii) Ba/Ca and δ13C in several PF species from a large set of core-top sediment samples in the study region. Additionally, total organic carbon and total alkenones were also measured in the sediment. Our results showed the link between productivity proxies in the surface sediment foraminifera assemblage and the processes regulating the actual phytoplankton dynamics in an upwelling area. The understanding of this relationship has special relevance since it gives fundamental information related to the past oceanic biogeochemistry and/or climate and improves the prevision of future changes against possible climate variability due to anthropogenic forcing.

Planktonic foraminiferal biostratigraphy of the Upper Barremian and Aptian of Crimea

Science.gov (United States)

Brovina, E. A.

2017-09-01

Reexamination of the Barremian-Aptian planktonic foraminifers from three sections (Verkhoirechie, mountain Krasnaya, and Marino) allowed the biostratigraphic scheme for Southwest and Central Crimea to be refined and updated. The following standard zones are recognized in the studied sections: Blowiella blowi (upper Barremian), Hedbergella excelsa (upper Barremian-lower Aptian), Leupoldina cabri (lower Aptian), H. luterbacheri, Globigerinelloides ferreolensis, Gl. barri, Gl. algerianus, Hedbergella trocoidea, Paraticinella rohri (upper Aptian). Beds with Hedbergella ruka are recognized in the B. blowi Zone. Foraminifers from the Partizanskoe section, representing the lower Aptian L. cabri and H. luterbacheri zones, are studied. The recognized strata are correlated with ammonite and nannoplankton zones and paleomagnetic data.

Surface ocean metabarcoding confirms limited diversity in planktonic foraminifera but reveals unknown hyper-abundant lineages.

Science.gov (United States)

Morard, Raphaël; Garet-Delmas, Marie-José; Mahé, Frédéric; Romac, Sarah; Poulain, Julie; Kucera, Michal; de Vargas, Colomban

2018-02-07

Since the advent of DNA metabarcoding surveys, the planktonic realm is considered a treasure trove of diversity, inhabited by a small number of abundant taxa, and a hugely diverse and taxonomically uncharacterized consortium of rare species. Here we assess if the apparent underestimation of plankton diversity applies universally. We target planktonic foraminifera, a group of protists whose known morphological diversity is limited, taxonomically resolved and linked to ribosomal DNA barcodes. We generated a pyrosequencing dataset of ~100,000 partial 18S rRNA foraminiferal sequences from 32 size fractioned photic-zone plankton samples collected at 8 stations in the Indian and Atlantic Oceans during the Tara Oceans expedition (2009-2012). We identified 69 genetic types belonging to 41 morphotaxa in our metabarcoding dataset. The diversity saturated at local and regional scale as well as in the three size fractions and the two depths sampled indicating that the diversity of foraminifera is modest and finite. The large majority of the newly discovered lineages occur in the small size fraction, neglected by classical taxonomy. These unknown lineages dominate the bulk [>0.8 µm] size fraction, implying that a considerable part of the planktonic foraminifera community biomass has its origin in unknown lineages.

Foraminiferal record of Holocene paleo-earthquakes on the subsiding south-western Poverty Bay coastline, New Zealand

International Nuclear Information System (INIS)

Hayward, B.W.; Sabaa, A.T.; Grenfell, H.R.; Cochran, U.A.; Clark, K.J.; Litchfield, N.J.; Wallace, L.M.; Marden, M.; Palmer, A.S.

2015-01-01

Foraminiferal faunas in 29 short cores (maximum depth 7 m) of estuarine and coastal wetland sediment were used to reconstruct the middle-late Holocene (last 7 ka) elevational history on the southern shores of Poverty Bay, North Island, New Zealand. This coast is on the southwest side of a rapidly subsiding area beneath western Poverty Bay. Modern Analogue Technique paleo-elevation estimates based on fossil foraminiferal faunas indicate that the four study areas have gradual late Holocene (<3.5 ka) subsidence rates that increase from the southwest (mean c. 0.5 m ka - - 1 ) to northeast (mean c. 1.0 m ka -1 ). Only two rapid, possibly co-seismic, vertical displacement events are recognised: (1) c. 1.2 m of subsidence at 5.7 ± 0.4 ka (cal yr BP), which may have been generated by a subduction interface earthquake centred offshore and recorded in other published studies in northern Hawkes Bay, c. 35 km to the south; and (2) c. 1 m of uplift (relative sea-level fall) at c. 4.5 ± 0.3 ka, which might have been generated by rupture on an offshore upper plate fault that also uplifted coastal terraces at Pakarae and Mahia, 40 km to the north and south of the study area, or by rupture on the subduction interface penetrating beneath Poverty Bay. No sudden displacement events are recognised during the last 4 ka although subsidence, possibly aseismic, has continued. (author).

Bottom-up effects of climate on fish populations: data from the Continuous Plankton Recorder

DEFF Research Database (Denmark)

Pitois, S.G.; Lynam, C.P.; Jansen, Teunis

2012-01-01

The Continuous Plankton Recorder (CPR) dataset on fish larvae has an extensive spatio-temporal coverage that allows the responses of fish populations to past changes in climate variability, including abrupt changes such as regime shifts, to be investigated. The newly available dataset offers...... in the plankton ecosystem, while the larvae of migratory species such as Atlantic mackerel responded more to hydrographic changes. Climate variability seems more likely to influence fish populations through bottom-up control via a cascading effect from changes in the North Atlantic Oscillation (NAO) impacting...... with fishing effects interacting with climate effects and this study supports furthering our under - standing of such interactions before attempting to predict how fish populations respond to climate variability...

Primary elements and trace elements in foraminiferal shells - indicators of climatic and oceanographic changes in the northern North Atlantic in the late Quaternary period. Haupt- und Spurenelemente in Foraminiferengehaeusen - Hinweise auf klimatische und ozeanographische Aenderungen im noerdlichen Nordatlantik waehrend des Spaetquartaers

Energy Technology Data Exchange (ETDEWEB)

Nuernberg, D

1991-01-01

Chemical elements in calcitic foraminiferal tests may serve to reconstruct the spatial and temporal variability as well as the thermal history of deep and surface water masses. Multi-element analyses of benthic (Cassidulina spp., C. wuellerstorfi, O. umbonatus, H. elegans, Uvigerina spp.) and planktonic foraminiferal tests (N. pachyderma sin.) performed by microprobe reveal relations between the geochemical composition of foraminiferal tests and oceanographic and climatic parameters: the analysis of magnesium in calcitic foraminiferal tests makes the thermal reconstruction of surface water masses possible. Cadmium and barium as paleoproductivity indicators in bottom and surface water masses may reveal oceanographic changes sediment cores along a transect reaching from the Rockall Plateau in the northeastern North Atlantic to the Fram Street and lying under the influence of the north Atlantic Drift and the Norwegian Current were used to systematically investigate geochemical variations for several glacial/interglacial changes down to oxygen isotope stage 6 (approximately the last 180,000 years). (orig.).

Analysis of Benthic Foraminiferal Size Change During the Eocene-Oligocene Transition

Science.gov (United States)

Zachary, W.; Keating-Bitonti, C.

2017-12-01

The Eocene-Oligocene transition is a significant global cooling event with the first growth of continental ice on Antarctica. In the geologic record, the size of fossils can be used to indirectly observe how organisms respond to climate change. For example, organisms tend to be larger in cooler environments as a physiological response to temperature. This major global cooling event should influence organism physiology, resulting in significant size trends observed in the fossil record. Benthic foraminifera are protists and those that grow a carbonate shell are both well-preserved and abundant in marine sediments. Here, we used the foraminiferal fossil record to study the relationship between their size and global cooling. We hypothesize that cooler temperatures across the Eocene-Oligocene boundary promoted shell size increase. To test this hypothesis, we studied benthic foraminifera from 10 deep-sea cores drilled at Ocean Drilling Program Site 744, located in the southern Indian Ocean. We washed sediment samples over a 63-micron sieve and picked foraminifera from a 125-micron sieve. We studied the benthic foraminiferal genus Cibicidoides and its size change across this cooling event. Picked specimens were imaged and we measured the diameter of their shells using "imageJ". Overall, we find that Cibicidoides shows a general trend of increasing size during this transition. In particular, both the median and maximum sizes of Cibicidoides increase from the Eocene into the Oligocene. We also analyzed C. pachyderma and C. mundulus for size trends. Although both species increase in median size across the boundary, only C. pachyderma shows a consistent trend of increasing maximum, median, and minimum shell diameter. After the Eocene-Oligocene boundary, we observe that shell diameter decreases following peak cooling and that foraminiferal sizes remain stable into the early Oligocene. Therefore, the Eocene-Oligocene cooling event appears to have strong influence on shell size.

Biostratigraphy of the Cretaceous/Tertiary boundary in the Sirwan Valley (Sulaimani Region, Kurdistan, NE Iraq)

Science.gov (United States)

Sharbazheri, Khalid Mahmood; Ghafor, Imad Mahmood; Muhammed, Qahtan Ahmad

2009-10-01

The Cretaceous/Tertiary (K/T) boundary sequence, which crops out in the studied area is located within the High Folded Zone, in the Sirwan Valley, northeastern Iraq. These units mainly consist of flysch and flysch-type successions of thick clastic beds of Tanjero/Kolosh Formations. A detailed lithostratigraphic study is achieved on the outcropping uppermost part of the Upper Cretaceous successions (upper part of Tanjero Formation) and the lowermost part of the Kolosh Formation. On the basis of the identified planktonic foraminiferal assemblages, five biozones are recorded from the uppermost part of Tanjero Formation and four biozones from the lower part of the Kolosh Formation (Lower Paleocene) in the Sirwan section. The biostratigraphic correlations based on planktonic foraminiferal zonations showed a comparison between the biostratigraphic zones established in this study and other equivalents of the commonly used planktonic zonal scheme around the Cretaceous/Tertiary boundary in and outside Iraq.

Worldwide Genotyping in the Planktonic Foraminifer Globoconella inflata: Implications for Life History and Paleoceanography

Science.gov (United States)

Morard, Raphaël; Quillévéré, Frédéric; Douady, Christophe J.; de Vargas, Colomban; de Garidel-Thoron, Thibault; Escarguel, Gilles

2011-01-01

The planktonic foraminiferal morpho-species Globoconella inflata is widely used as a stratigraphic and paleoceanographic index. While G. inflata was until now regarded as a single species, we show that it rather constitutes a complex of two pseudo-cryptic species. Our study is based on SSU and ITS rDNA sequence analyses and genotyping of 497 individuals collected at 49 oceanic stations covering the worldwide range of the morpho-species. Phylogenetic analyses unveil the presence of two divergent genotypes. Type I inhabits transitional and subtropical waters of both hemispheres, while Type II is restricted to the Antarctic subpolar waters. The two genetic species exhibit a strictly allopatric distribution on each side of the Antarctic Subpolar Front. On the other hand, sediment data show that G. inflata was restricted to transitional and subtropical environments since the early Pliocene, and expanded its geographic range to southern subpolar waters ∼700 kyrs ago, during marine isotopic stage 17. This datum may correspond to a peripatric speciation event that led to the partition of an ancestral genotype into two distinct evolutionary units. Biometric measurements performed on individual G. inflata from plankton tows north and south of the Antarctic Subpolar Front indicate that Types I and II display slight but significant differences in shell morphology. These morphological differences may allow recognition of the G. inflata pseudo-cryptic species back into the fossil record, which in turn may contribute to monitor past movements of the Antarctic Subpolar Front during the middle and late Pleistocene. PMID:22028935

A high-resolution record of Holocene millennial-scale oscillations of surface water, foraminiferal paleoecology and sediment redox chemistry in the SE Brazilian margin

Science.gov (United States)

Dias, B. B.; Barbosa, C. F.; Albuquerque, A. L.; Piotrowski, A. M.

2014-12-01

Holocene millennial-scale oscillations and Bond Events (Bond et al. 1997) are well reported in the North Atlantic as consequence of fresh water input and weaking of the Atlantic Meridional Overturning Circulation (AMOC). It has been hypothesized that the effect of weaking of AMOC would lead to warming in the South Atlantic due to "heat piracy", causing surface waters to warm and a reorganization of surface circulation. There are few reconstructions of AMOC strength in the South Atlantic, and none with a high resolution Holocene record of changes of productivity and the biological pump. We reconstruct past changes in the surface water mass hydrography, productivity, and sediment redox changes in high-resolution in the core KCF10-01B, located 128 mbsl water depth off Cabo Frio, Brazil, a location where upwelling is strongly linked to surface ocean hydrography. We use Benthic Foraminiferal Accumulation Rate (BFAR) to reconstruct productivity, which reveals a 1.3kyr cyclicity during the mid- and late-Holocene. The geochemistry of trace and rare earth elements on foraminiferal Fe-Mn oxide coatings show changes in redox-sensitive elements indicating that during periods of high productivity there were more reducing conditions in sediment porewaters, producing a Ce anomaly and reduction and re-precipitation of Mn oxides. Bond events 1-7 were identified by a productivity increase along with reducing sediment conditions which was likely caused by Brazil Current displacement offshore allowing upwelling of the nutritive bottom water South Atlantic Central Waters (SACW) to the euphotic zone and a stronger local biological pump. In a global context, correlation with other records show that this occurred during weakened AMOC and southward displacement of the ITCZ. We conclude that Bond climatic events and millennial-scale variability of AMOC caused sea surface hydrographic changes off the Brazilian Margin leading to biological and geochemical changes recorded in coastal records

Foraminiferal fauna from the Cochin backwaters: Biological indicators of man-made changes in the environment

Digital Repository Service at National Institute of Oceanography (India)

Rao, K.K.

Sixty foraminiferal species belonging to 38 genera and 23 families have been recorded from grab sediments of the Cochin backwaters. Of all the species Ammonia baccarii is the most dominant and successful form in the throes of fluctuating salinities...

Stable isotope stratigraphy and larger benthic foraminiferal extinctions in the Melinau Limestone, Sarawak

Science.gov (United States)

Cotton, Laura J.; Pearson, Paul N.; Renema, Willem

2014-01-01

Important long-ranging groups of larger benthic foraminifera (LBF) are known to have become extinct during a period of global cooling and climate disruption at the Eocene-Oligocene transition (EOT) but the precise timing and mechanisms are uncertain. Recent study showed unexpectedly that the LBF extinction in Tanzania occurs very close to the Eocene/Oligocene boundary, as recognised by the extinction of the planktonic foraminiferal Family Hantkeninidae, rather than at the later period of maximum global ice growth and sea-level fall, as previously thought. Here we investigate the same phase of extinction in the Melinau Limestone of Sarawak, on the island of Borneo, Malaysia one of the most complete carbonate successions spanning the Eocene to Lower Miocene. Assemblages of LBF from the Melinau Limestone were studied extensively by Geoffrey Adams during the 1960s-80s, confirming a major extinction during the EOT, but the section lacked independent means of correlation. By analysing rock samples originally studied by Adams and now in the Natural History Museum, London, we provide new bulk stable isotope (δ13C and δ18O) records. This enables us to identify, albeit tentatively, the level of maximum stable isotope excursion and show that the LBF extinction event in the Melinau Limestone occurs below this isotope excursion, supporting the results from Tanzania and indicating that the extinction of LBF close to the Eocene/Oligocene boundary may be a global phenomenon.

Benthic foraminiferal Mn / Ca ratios reflect microhabitat preferences

Science.gov (United States)

Koho, Karoliina A.; de Nooijer, Lennart J.; Fontanier, Christophe; Toyofuku, Takashi; Oguri, Kazumasa; Kitazato, Hiroshi; Reichart, Gert-Jan

2017-06-01

The Mn / Ca of calcium carbonate tests of living (rose-Bengal-stained) benthic foraminifera (Elphidium batialis, Uvigerina spp., Bolivina spissa, Nonionellina labradorica and Chilostomellina fimbriata) were determined in relation to pore water manganese (Mn) concentrations for the first time along a bottom water oxygen gradient across the continental slope along the NE Japan margin (western Pacific). The local bottom water oxygen (BWO) gradient differs from previous field study sites focusing on foraminiferal Mn / Ca and redox chemistry, therefore allowing further resolution of previously observed trends. The Mn / Ca ratios were analysed using laser ablation inductively coupled plasma-mass spectrometer (ICP-MS), allowing single-chamber determination of Mn / Ca. The incorporation of Mn into the carbonate tests reflects environmental conditions and is not influenced by ontogeny. The inter-species variability in Mn / Ca reflected foraminiferal in-sediment habitat preferences and associated pore water chemistry but also showed large interspecific differences in Mn partitioning. At each station, Mn / Ca ratios were always lower in the shallow infaunal E. batialis, occupying relatively oxygenated sediments, compared to intermediate infaunal species, Uvigerina spp. and B. spissa, which were typically found at greater depth, under more reducing conditions. The highest Mn / Ca was always recorded by the deep infaunal species N. labradorica and C. fimbriata. Our results suggest that although partitioning differs, Mn / Ca ratios in the intermediate infaunal taxa are promising tools for palaeoceanographic reconstructions as their microhabitat exposes them to higher variability in pore water Mn, thereby making them relatively sensitive recorders of redox conditions and/or bottom water oxygenation.

Foraminiferal proxies for pollution monitoring in moderately polluted harbors

International Nuclear Information System (INIS)

Armynot du Chatelet, E.; Debenay, J.-P.; Soulard, R.

2004-01-01

Foraminiferal density and species richness that decrease with an increase in heavy metal and PAH concentration may be used as pollution indicators. - Benthic foraminifera are increasingly used as environmental bio-indicators, especially in polluted environments where their sensitivity to pollutants may be expressed by a modification of the assemblages. Eighteen sediment samples were collected in September 2000 in five harbors located in moderately polluted estuaries on the coast of Vendee (France) for the study of foraminiferal assemblages. Ten heavy metals and 13 PAH have been analyzed from the sediments. The marine to continental estuarine gradient has a prevalent influence on the foraminiferal distribution. However, the results show that foraminiferal density and species richness of the assemblages decrease with an increase in heavy metal and PAH concentration, and therefore may be used as pollution indicators. Moreover, the more polluted areas are dominated by the tolerant pioneer species Haynesina germanica that may be used as bio-indicator of pollution, mainly in the uppermost areas

First records of two planktonic Indo-Pacific diatoms: Chaetoceros bacteriastroides and C. pseudosymmetricus in the Adriatic Sea

Directory of Open Access Journals (Sweden)

Marijeta Čalić

2018-01-01

Full Text Available Unusual occurrence of planktonic diatom species, Chaetoceros bacteriastroides and Chaetoceros pseudosymmetricus, was noticed in three different marine ecosystems of Adriatic Sea: the Krka Estuary and Telaščica Bay in the Central Adriatic, and in southern Adriatic offshore. From 2010 to 2015, these two Chaetoceros species were recorded in heterogeneous environmental conditions and in a very low abundances. Both species are regarded as very rare in world oceans, and consequently knowledge of their distribution and ecology is rather poor. Primarily described from tropical waters and showing Indo-Pacific distribution, C. bacteriastroides and C. pseudosymmetricus findings in Adriatic represent the northernmost records in world's oceans and seas. For C. pseudosymmetricus this is also the first occurrence in European seas. Areal expansion and introduction of new phytoplankton species in the Adriatic Sea might be related to different circulation regimes in the Ionian Sea and the concurrent rise in sea temperature in the Mediterranean in the last decade. Recent investigations have shown that entering currents, of either Atlantic/Western Mediterranean or Eastern Mediterranean origin, modify the composition of the plankton community in the Adriatic by bringing different newcomers.

Larval and Juvenile Ascothoracida (Crustacea) from the Plankton

OpenAIRE

Grygier, Mark J.

1988-01-01

Two kinds of previously recorded ascothoracid larvae from plankton over coral reefs in Hawaii and the Virgin Islands are redescribed as possible representatives of the Lauridae and Petrarcidae, respectively. A bathyal, tropical Atlantic ascothoracid larva from an epibenthic sled sample cannot confidently be identified to family. A planktonic, juvenile ascothoracidan from the eastern Indian Ocean belongs to the genus Synagoga.

Tracing the incorporation of carbon into benthic foraminiferal calcite following the Deepwater Horizon event.

Science.gov (United States)

Schwing, Patrick T; Chanton, Jeffrey P; Romero, Isabel C; Hollander, David J; Goddard, Ethan A; Brooks, Gregg R; Larson, Rebekka A

2018-06-01

Following the Deepwater Horizon (DWH) event in 2010, hydrocarbons were deposited on the continental slope in the northeastern Gulf of Mexico through marine oil snow sedimentation and flocculent accumulation (MOSSFA). The objective of this study was to test the hypothesis that benthic foraminiferal δ 13 C would record this depositional event. From December 2010 to August 2014, a time-series of sediment cores was collected at two impacted sites and one control site in the northeastern Gulf of Mexico. Short-lived radioisotopes ( 210 Pb and 234 Th) were employed to establish the pre-DWH, DWH, and post-DWH intervals. Benthic foraminifera (Cibicidoides spp. and Uvigerina spp.) were isolated from these intervals for δ 13 C measurement. A modest (0.2-0.4‰), but persistent δ 13 C depletion in the DWH intervals of impacted sites was observed over a two-year period. This difference was significantly beyond the pre-DWH (background) variability and demonstrated that benthic foraminiferal calcite recorded the depositional event. The longevity of the depletion in the δ 13 C record suggested that benthic foraminifera may have recorded the change in organic matter caused by MOSSFA from 2010 to 2012. These findings have implications for assessing the subsurface spatial distribution of the DWH MOSSFA event. Copyright © 2018 Elsevier Ltd. All rights reserved.

Variations of the paleo-productivity in benthic foraminifera records in MIS 3 from western South China Sea

Science.gov (United States)

Niu, Y.; Du, J.; Huang, B.; Chen, M.

2010-12-01

Understanding climate change of last glacial age as the background information of climate forecasting is particularly important in climate research. Marine Isotope Stage 3 (MIS 3, 61-24 ka B.P.) is a relative warm and unstable period in the last glacial. Millennium scale abrupt climate changes, such as Heinrich events and Dansgaard-Oeschger (D-O) cycles, are identified in this period. Research topic on the variations of monsoon during the glacial cycles, especially in MIS 3, is critical for understanding low latitude climatic change and the global paleo-environment as a whole. Fortunately, high resolution sedimentary records in western South China Sea provide us valuable materials to uncover how East Asia Summer Monsoon (EASM) system acts in a highly fluctuating climate ambient like MIS 3. Core 17954 is located in the modern summer upwelling area off the Vietnam coast in western South China Sea (SCS), its sediments record the variations of upwelling generated by EASM. In this work, we carry out paleo-ecological analyses on planktonic ( Neogloboquadrina dutertrei, Globigerina bulloides) and benthic foraminifera (Bulimina aculeate, Uvigerina peregrina, Cibicidoides wuellerstorfi, ect.) sampled from Core 17954 to investigate paleo-productivity and nutrition change of western SCS and its relation to EASM. The results show that benthic and planktonic foraminifera have similar responses to nutrition change. Various indicators of productivity on the basis of benthic foraminiferal analyses reflect an overall three stage change trend: productivity gradually increases from the beginning of MIS 3 (60-40 ka) to its maximum during 35-30 ka, and finally declines after 30 ka. There is also another important discovery, if we observe the climate change in MIS 3 as a whole, we can also find western SCS and Northern Hemisphere High latitude have strong correspondences in such changes: Heinrich events coincided with high productivity events in the western SCS. Further, the result of

A foraminiferal testimony for the reduced adverse effects of mining in Zuari Estuary, Goa

Digital Repository Service at National Institute of Oceanography (India)

Panchang, R.; Nigam, R.; Baig, N.; Nayak, G.N.

the health of the Zuari through foraminiferal distribution in its surface sediments. The foraminiferal data generated was compared with the three-decade-old foraminiferal data collected in 1972 and total suspended matter (TSM) data over the years. There has...

Temporal assemblage turnovers of intertidal foraminiferal communities from tropical (SE Caribbean) and temperate (NE England and SW Spain) regions

Science.gov (United States)

Costelloe, Ashleigh; Wilson, Brent; Horton, Benjamin P.; Hayek, Lee-Ann C.

2018-05-01

This is the first quantitative study of temporal assemblage turnovers of the relationships between intertidal foraminifera. Time series datasets collected from tropical Caroni Swamp and Claxton Bay (Trinidad, SE Caribbean) and temperate Cowpen Marsh (NE England, U.K.) and Bay of Cadiz (SW Spain) were used. The assemblage turnover index (ATI) examined species interrelationships through comparisons of monthly or biweekly species proportional abundances over one or two years. Species contributing to major assemblage turnovers (ATI > x + σ) were identified using the conditioned on-boundary index (CoBI). Foraminiferal species are heterogeneously distributed within the sediment; multiple sample stations at a study location cumulatively represent the foraminiferal metacommunity and clusters represent foraminiferal assemblages. The ATI and CoBI were applied to the proportional abundances of live specimens recorded for the metacommunity and assemblages at each location. At Caroni Swamp and Claxton Bay, major assemblage turnovers were driven by the most abundant species and the majority coincided with seasonal change or the arrival of the seasonal Orinoco plume in the Gulf of Paria. Seasonal turnovers of the foraminiferal metacommunities at temperate Cowpen Marsh and Bay of Cádiz occurred during the summer and winter. Major assemblage turnovers in the upper Cowpen Marsh occurred in the summer, and the lower marsh in the winter. Foraminiferans are useful bioindicators for monitoring the health of coastal environments. Understanding foraminiferal population dynamics will allow cyclical changes to be differentiated from abrupt and persistent changes, which are related to anthropogenic disturbances or long-term climate change. The ATI and CoBI are useful indices for quantitatively exploring relationships of foraminiferal populations over time.

The FOBIMO (FOraminiferal BIo-MOnitoring) initiative—Towards a standardised protocol for soft-bottom benthic foraminiferal monitoring studies

Science.gov (United States)

Schoenfeld, Joachim; Alve, Elisabeth; Geslin, Emmanuelle; Jorissen, Frans; Korsun, Sergei; Spezzaferri, Silva; Abramovich, Sigal; Almogi-Labin, Ahuva; Armynot du Chatelet, Eric; Barras, Christine; Bergamin, Luisa; Bicchi, Erica; Bouchet, Vincent; Cearreta, Alejandro; Di Bella, Letizia; Dijkstra, Noortje; Trevisan Disaro, Sibelle; Ferraro, Luciana; Frontalini, Fabrizio; Gennari, Giordana; Golikova, Elena; Haynert, Kristin; Hess, Silvia; Husum, Katrine; Martins, Virginia; McGann, Mary; Oron, Shai; Romano, Elena; Mello Sousa, Silvia; Tsujimoto, Akira

2012-01-01

The European Community Marine Strategy Framework Directive (MSFD) was established to provide guidelines for monitoring the quality of marine ecosystems. Monitoring the status of marine environments is traditionally based on macrofauna surveys, for which standardised methods have been established. Benthic foraminifera are also good indicators of environmental status because of their fast turnover rates, high degree of specialisation, and the preservation of dead assemblages in the fossil record. In spite of the growing interest in foraminiferal bio-monitoring during the last decades, no standardised methodology has been proposed until today. The aim of the FOraminiferal BIo-MOnitoring (FOBIMO) expert workshop, held in June 2011 at Fribourg, Switzerland, which assembled 37 scientists from 24 research groups and 13 countries, was to develop a suite of standard methods. This paper presents the main outcome of the workshop, a list of motivated recommendations with respect to sampling devices, sample storage, treatment, faunal analysis and documentation. Our recommendations fulfil the criteria imposed both by scientific rigour and by the practical limitations of routine studies. Hence, our aim is to standardise methodologies used in bio-monitoring only and not to limit the use of different methods in pure scientific studies. Unless otherwise stated, all recommendations concern living (stained) benthic foraminiferal assemblages. We have chosen to propose two types of recommendations. Mandatory recommendations have to be followed if a study wants to qualify as sound and compatible to the norms. The most important of these recommendations are the interval from 0 to 1 cm below the sediment surface has to be sampled, and an interface corer or box corer that keeps the sediment surface intact is to be used for offshore surveys. A grab sampler must not be deployed in soft sediments. Three replicate samples are to be taken and analysed separately. Samples are to be washed on a

Benthic foraminiferal response to the emergence of the Isthmus of Panama and coincident paleoceanographic changes

Science.gov (United States)

McDougall, K.

1996-01-01

Late Cenozoic benthic foraminiferal faunas from the Caribbean Deep Sea Drilling Project (DSDP) Site 502 (3052 m) and East Pacific DSDP Site 503 (3572 m) were analyzed to interpret bottom-water masses and paleoceanographic changes occurring as the Isthmus of Panama emerged. Major changes during the past 7 Myr occur at 6.7-6.2, 3.4, 2.0, and 1.1 Ma in the Caribbean and 6.7-6.4, 4.0-3.2, 2.1, 1.4, and 0.7 Ma in the Pacific. Prior to 6.7 Ma, benthic foraminiferal faunas at both sites indicate the presence of Antarctic Bottom Water (AABW). After 6.7 Ma benthic foraminiferal faunas indicate a shift to warmer water masses: North Atlantic Deep Water (NADW) in the Caribbean and Pacific Deep Water (PDW) in the Pacific. Flow of NADW may have continued across the rising sill between the Caribbean and Pacific until 5.6 Ma when the Pacific benthic foraminiferal faunas suggest a decrease in bottom-water temperatures. After 5.6 Ma deep-water to intermediate-water flow across the sill appears to have stopped as the bottom-water masses on either side of the sill diverge. The second change recorded by benthic foraminiferal faunas occurs at 3.4 Ma in the Caribbean and 4.0-3.2 Ma in the Pacific. At this time the Caribbean is flooded with cold AABW, which is either gradually warmed or is replaced by Glacial Bottom Water (GBW) at 2.0 Ma and by NADW at 1.1 Ma. These changes are related to global climatic events and to the depth of the sill between the Caribbean and Atlantic rather than the rising Isthmus of Panama. Benthic foraminiferal faunas at East Pacific Site 503 indicate a gradual change from cold PDW to warmer PDW between 4.0 and 3.2 Ma. The PDW is replaced by the warmer, poorly oxygenated PIW at 2.1 Ma. Although the PDW affects the faunas during colder intervals between 1.4 and 0.7 Ma, the PIW remains the principal bottom- water mass in the Guatemala Basin of the East Pacific.

Early Palaeogene planktic foraminiferal and carbon isotope stratigraphy, ODP hole 762C, Exmouth plateau, Northwest Australian margin

International Nuclear Information System (INIS)

Hancock, H.J.L.; Dickens, G.R.; Henderson, R.R.; Chaproniere, G.C.

1999-01-01

recalibrated magnetostratigraphy, the planktic foraminiferal record at Site 762 provides an integrated and detailed early Palaeogene stratigraphy for the North West Shelf. Importantly a complete, expanded and shallow buried early Palaeogene sediment record exists on the Exmouth Plateau. The location is ideal for future scientific drilling to understand profound palaeoceanographic variations in the Palaeogene. Copyright (1999) Geological Society of Australia

Benthic foraminiferal Mn / Ca ratios reflect microhabitat preferences

Directory of Open Access Journals (Sweden)

K. A. Koho

2017-06-01

Full Text Available The Mn / Ca of calcium carbonate tests of living (rose-Bengal-stained benthic foraminifera (Elphidium batialis, Uvigerina spp., Bolivina spissa, Nonionellina labradorica and Chilostomellina fimbriata were determined in relation to pore water manganese (Mn concentrations for the first time along a bottom water oxygen gradient across the continental slope along the NE Japan margin (western Pacific. The local bottom water oxygen (BWO gradient differs from previous field study sites focusing on foraminiferal Mn / Ca and redox chemistry, therefore allowing further resolution of previously observed trends. The Mn / Ca ratios were analysed using laser ablation inductively coupled plasma-mass spectrometer (ICP-MS, allowing single-chamber determination of Mn / Ca. The incorporation of Mn into the carbonate tests reflects environmental conditions and is not influenced by ontogeny. The inter-species variability in Mn / Ca reflected foraminiferal in-sediment habitat preferences and associated pore water chemistry but also showed large interspecific differences in Mn partitioning. At each station, Mn / Ca ratios were always lower in the shallow infaunal E. batialis, occupying relatively oxygenated sediments, compared to intermediate infaunal species, Uvigerina spp. and B. spissa, which were typically found at greater depth, under more reducing conditions. The highest Mn / Ca was always recorded by the deep infaunal species N. labradorica and C. fimbriata. Our results suggest that although partitioning differs, Mn / Ca ratios in the intermediate infaunal taxa are promising tools for palaeoceanographic reconstructions as their microhabitat exposes them to higher variability in pore water Mn, thereby making them relatively sensitive recorders of redox conditions and/or bottom water oxygenation.

Benthic monitoring of salmon farms in Norway using foraminiferal metabarcoding

DEFF Research Database (Denmark)

Pawlowski, Jan; Esling, Philippe; Lejzerowicz, Franck

2016-01-01

The rapid growth of the salmon industry necessitates the development of fast and accurate tools to assess its environmental impact. Macrobenthic monitoring is commonly used to measure the impact of organic enrichment associated with salmon farm activities. However, classical benthic monitoring can...... of macrofauna-based benthic monitoring. Here, we tested the application of foraminiferal metabarcoding to benthic monitoring of salmon farms in Norway. We analysed 140 samples of eDNA and environmental RNA (eRNA) extracted from surface sediment samples collected at 4 salmon farming sites in Norway. We sequenced...... of Foraminifera as bioindicators of organic enrichment associated with salmon farming. The foraminiferal diversity increased with the distance to fish cages, and metabarcoding provides an assessment of the ecological quality comparable to the morphological analyses. The foraminiferal metabarcoding approach...

Paleomonsoon records from the western Arabian Sea: evidence of aeolian input and Red Sea water inflow

International Nuclear Information System (INIS)

Tiwari, M.; Ramesh, R.; Bhushan, R.; Somayajulu, B.L.K.; Jull, A.J.T.; Burr, G.S.; Sheshshayee, M.S.

2004-01-01

The western Arabian Sea experiences intense productivity variations due to wind-induced upwelling during the South West monsoon. Variations in calcareous productivity derived from marine sediment cores can prove to be an excellent indicator of monsoon wind strength provided that the core has been raised from water depths well above the lysocline (∼4000 m). The core was radiocarbon dated by on select planktonic foraminiferal species viz. Globigerinoides ruber, Globigerinoides sacculifer, Orbulina universa and Neogloboquadrina dutertrei (size range chosen for dating as well as isotopic analysis is 250 μ -500 μ. Planktonic foraminifera were selected for our study because they inhabit the surface and near surface oceans (upto∼ 100 m) and, therefore, readily incorporate changes occurring in the surface ocean into their calcitic shells

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

Directory of Open Access Journals (Sweden)

L. Jonkers

2017-06-01

Full Text Available 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

Planktonic percentage of foraminiferal fauna in surface sediments of the Arabian sea (Indian Ocean) and a regional model for paleodepth determination

Digital Repository Service at National Institute of Oceanography (India)

Nigam, R.; Henriques, P.J.

with previous studies in other areas that planktonic percentage increased with depth. The resultant pattern is compared with results from the Atlantic margin of the northeastern United States, Gulf of Mexico, Timor Sea and Red Sea. Comparisons reveal...

Latest Holocene Climate Variability revealed by a high-resolution multiple Proxy Record off Lisbon (Portugal)

Science.gov (United States)

Abrantes, F.; Lebreiro, S.; Ferreira, A.; Gil, I.; Jonsdottir, H.; Rodrigues, T.; Kissel, C.; Grimalt, J.

2003-04-01

The North Atlantic Oscillation (NAO) is known to have a major influence on the wintertime climate of the Atlantic basin and surrounding countries, determining precipitation and wind conditions at mid-latitudes. A comparison of Hurrel's NAO index to the mean winter (January-March) discharge of the Iberian Tagus River reveals a good negative correlation to negative NAO, while the years of largest upwelling anomalies, as referred in the literature, appear to be in good agreement with positive NAO. On this basis, a better understanding of the long-term variability of the NAO and Atlantic climate variability can be gained from high-resolution climate records from the Lisbon area. Climate variability of the last 2,000 years is assessed through a multiple proxy study of sedimentary sequences recovered from the Tagus prodelta deposition center, off Lisbon (Western Iberia). Physical properties, XRF and magnetic properties from core logging, grain size, δ18O, TOC, CaCO3, total alkenones, n-alkanes, alkenone SST, diatoms, benthic and planktonic foraminiferal assemblage compositions and fluxes are the proxies employed. The age model for site D13902 is based on AMS C-14 dates from mollusc and planktonic foraminifera shells, the reservoir correction for which was obtained by dating 3 pre-bomb, mollusc shells from the study area. Preliminary results indicate a Little Ice Age (LIA - 1300 - 1600 AD) alkenone derived SSTs around 15 degC followed by a sharp and rapid increase towards 19 degC. In spite the strong variability observed for most records, this low temperature interval is marked by a general increase in organic carbon, total alkenone concentration, diatom and foraminiferal abundances, as well as an increase in the sediment fine fraction and XRF determined Fe content, pointing to important river input and higher productivity. The Medieval Warm Period (1080 - 1300 AD) is characterized by 17-18 degC SSTs, increased mean grain size, but lower magnetic susceptibility and Fe

Boron isotope-based seasonal paleo-pH reconstruction for the Southeast Atlantic - A multispecies approach using habitat preference of planktonic foraminifera

Science.gov (United States)

Raitzsch, Markus; Bijma, Jelle; Benthien, Albert; Richter, Klaus-Uwe; Steinhoefel, Grit; Kučera, Michal

2018-04-01

The boron isotopic composition of planktonic foraminiferal shell calcite (δ11BCc) provides valuable information on the pH of ambient water at the time of calcification. Hence, δ11BCc of fossil surface-dwelling planktonic foraminifera can be used to reconstruct ancient aqueous pCO2 if information on a second carbonate system parameter, temperature and salinity is available. However, pH and pCO2 of surface waters may vary seasonally, largely due to changes in temperature, DIC, and alkalinity. As also the shell fluxes of planktonic foraminifera show species-specific seasonal patterns that are linked to intra-annual changes in temperature, it is obvious that δ11BCc of a certain species reflects the pH and thus pCO2 biased towards a specific time period within a year. This is important to consider for the interpretation of fossil δ11BCc records that may mirror seasonal pH signals. Here we present new Multi-Collector Inductively Coupled Mass Spectrometry (MC-ICPMS) δ11BCc coretop data for the planktonic foraminifera species Globigerina bulloides, Globigerinoides ruber, Trilobatus sacculifer and Orbulina universa and compare them with δ11Bborate derived from seasonally resolved carbonate system parameters. We show that the inferred season-adjusted δ11BCc /δ11Bborate relationships are similar to existing calibrations and can be combined with published δ11BCc field and culture data to augment paleo-pH calibrations. To test the applicability of these calibrations, we used a core drilled on the Walvis Ridge in the Southeast Atlantic spanning the last 330,000 years to reconstruct changes in surface-water pCO2. The reconstruction based on G. bulloides, which reflects the austral spring season, was shown to yield values that closely resemble the Vostok ice-core data indicating that surface-water pCO2 was close to equilibrium with the atmosphere during the cooler spring season. In contrast, pCO2 estimated from δ11BCc of O. universa, T. sacculifer and G. ruber that

Temporal changes in plankton of the North Sea: community shfits and environmental drivers

NARCIS (Netherlands)

Alvarez-Fernandez, S.; Lindeboom, H.J.; Meesters, H.W.G.

2012-01-01

This paper analyses long-term and seasonal changes in the North Sea plankton community during the period 1970 to 2008. Based on Continuous Plankton Recorder (CPR) data covering 38 yr, major changes in both phytoplankton and zooplankton abundance and community structure were identified. Regime

Studies in living and fossil foraminifers from seasonally productive regions

NARCIS (Netherlands)

Barmawidjaja, D.M.

1991-01-01

Paleoecological and paleoenvironmental analysis of benthic and planktonic foraminiferal associations from sediments from the northern Adriatic Sea, the Kau Basin (Halmahera) and the Molucca Sea shed new light on the way in which various environmental factors influence foraminiferal distribution

A 20 million year record of planktic foraminiferal B/Ca ratios: Systematics and uncertainties in pCO 2 reconstructions

Science.gov (United States)

Tripati, Aradhna K.; Roberts, Christopher D.; Eagle, Robert A.; Li, Gaojun

2011-05-01

We use new and published data representing a 20 million long record to discuss the systematics of interpreting planktic foraminiferal B/Ca ratios. B/Ca-based reconstructions of seawater carbonate chemistry and atmospheric pCO 2 assume that the incorporation of boron into foraminiferal tests can be empirically described by an apparent partition coefficient, KD={B/Ca}/{B(OH4-/HCO)} ( Hemming and Hanson, 1992). It has also been proposed that there is a species-specific relationship between K D and temperature ( Yu et al., 2007). As we discuss, although these relationships may be robust, there remain significant uncertainties over the controls on boron incorporation into foraminifera. It is difficult to be certain that the empirically defined correlation between temperature and K D is not simply a result of covariance of temperature and other hydrographic variables in the ocean, including carbonate system parameters. There is also some evidence that K D may be affected by solution [HCO3-]/[CO32-] ratios (i.e., pH), or by [CO32-]. In addition, the theoretical basis for the definition of K D and for a temperature control on K D is of debate. We also discuss the sensitivity of pCO 2 reconstructions to different K D-temperature calibrations and seawater B/Ca. If a K D-temperature calibration is estimated using ice core pCO 2 values between 0 and 200 ka, B/Ca ratios can be used to reasonably approximate atmospheric pCO 2 between 200 and 800 ka; however, the absolute values of pCO 2 calculated are sensitive to the choice of K D-temperature relationship. For older time periods, the absolute values of pCO 2 are also dependent on the evolution of seawater B concentrations. However, we find that over the last 20 Ma, reconstructed changes in declining pCO 2 across the Mid-Pleistocene Transition, Pliocene glacial intensification, and the Middle Miocene Climate Transition are supported by the B/Ca record even if a constant coretop K D is used, or different K D

Benthic foraminiferal assemblages: a clue to the palaeoecology and palaeoenvironment of the Pliensbachian- Toarcian transition of Peniche (Lusitanian Basin, Portugal)

Science.gov (United States)

Rita, Patrícia; Reolid, Matias; Duarte, Luís V.

2015-04-01

The Lower Jurassic of the Peniche region (Lusitanian Basin, Portugal) constitutes one of the most worldwide references concerning the stratigraphy of the Lower Toarcian. In fact, the Peniche Section is the unique candidate to the Toarcian Global Boundary Stratotype Section and Point and records some important evidences about the palaeoenvironmental perturbations associated to the Toarcian Oceanic Anoxic Event (T-OAE) (e.g. Hesselbo et al., 2007). Despite the large number of micropaleontological studies developed in this section (e.g. ostracods, calcareous nannofossils), any relevant study of benthic foraminifera has been presented, even to the whole basin scale. Thus, based on a detailed stratigraphic analysis that includes 39 marly samples of the Emaciatum (= Spinatum) - Levisoni (= Serpentinum) ammonite zone interval (around 37 m thick), the aim of this work is the study of the foraminiferal assemblages from the Pliensbachian-Toarcian boundary and across the T-OAE. The results and main conclusions of this preliminary study show three different stages: 1) The uppermost Pliensbachian (Emaciatum Zone) is characterized by foraminiferal assemblages with high diversity and abundance (foram/g) dominated by Marginulina, Lenticulina, Dentalina and Ammobaculites, suggesting well-oxygenation and nutrient availability. 2) The beginning of the Toarcian (Polymorphum Zone) evidences a drastic decrease of the diversity and abundance of the foraminiferal assemblages. 3) This trend continues in the Levisoni Zone with decreasing diversity and abundance (some barren samples are recorded), but opportunistic forms such as Epistomina and Lenticulina, occasionally proliferate. This evolution suggests a clear perturbation in the palaeocological conditions at the sea-bottom during the Early Toarcian, feature that is observed in other basins (see Reolid et al., 2012). The fluctuations of foraminiferal assemblages recorded across the studied interval seems to correlate with the previous

First evaluation of foraminiferal metabarcoding for monitoring environmental impact from an offshore oil drilling site

KAUST Repository

Laroche, Olivier

2016-08-29

At present, environmental impacts from offshore oil and gas activities are partly determined by measuring changes in macrofauna diversity. Morphological identification of macrofauna is time-consuming, expensive and dependent on taxonomic expertise. In this study, we evaluated the applicability of using foraminiferal-specific metabarcoding for routine monitoring. Sediment samples were collected along distance gradients from two oil platforms off Taranaki (New Zealand) and their physicochemical properties, foraminiferal environmental DNA/RNA, and macrofaunal composition analyzed. Macrofaunal and foraminiferal assemblages showed similar shifts along impact gradients, but responded differently to environmental perturbations. Macrofauna were affected by hypoxia, whereas sediment grain size appeared to drive shifts in foraminifera. We identified eight foraminiferal molecular operational taxonomic units that have potential to be used as bioindicator taxa. Our results show that metabarcoding represents an effective tool for assessing foraminiferal communities near offshore oil and gas platforms, and that it can be used to complement current monitoring techniques. (C) 2016 Elsevier Ltd. All rights reserved.

First evaluation of foraminiferal metabarcoding for monitoring environmental impact from an offshore oil drilling site

KAUST Repository

Laroche, Olivier; Wood, Susanna A.; Tremblay, Louis A.; Ellis, Joanne; Lejzerowicz, Franck; Pawlowski, Jan; Lear, Gavin; Atalah, Javier; Pochon, Xavier

2016-01-01

At present, environmental impacts from offshore oil and gas activities are partly determined by measuring changes in macrofauna diversity. Morphological identification of macrofauna is time-consuming, expensive and dependent on taxonomic expertise. In this study, we evaluated the applicability of using foraminiferal-specific metabarcoding for routine monitoring. Sediment samples were collected along distance gradients from two oil platforms off Taranaki (New Zealand) and their physicochemical properties, foraminiferal environmental DNA/RNA, and macrofaunal composition analyzed. Macrofaunal and foraminiferal assemblages showed similar shifts along impact gradients, but responded differently to environmental perturbations. Macrofauna were affected by hypoxia, whereas sediment grain size appeared to drive shifts in foraminifera. We identified eight foraminiferal molecular operational taxonomic units that have potential to be used as bioindicator taxa. Our results show that metabarcoding represents an effective tool for assessing foraminiferal communities near offshore oil and gas platforms, and that it can be used to complement current monitoring techniques. (C) 2016 Elsevier Ltd. All rights reserved.

Graphic pattern of foraminiferal dominance in nearshore region of central west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A.P.; Nigam, R.; Ambre, N.V.

Within the inner neritic zone (0-55 m depth) along the central west coast of India, some foraminiferal groups such as @iAmmonia, Elphidium, Trochammina, Bulimina, Bolivina, Nonion, Nonionella@@ and Florilus@@ individually (total foraminiferal number...

Influence of estuaries on shelf foraminiferal species

Digital Repository Service at National Institute of Oceanography (India)

Nigam, R.

Dabhol-bhatkal stretch of the west coast of India is marked by a number of estuaries. Cavarotalia annectens is selected to monitor the influence of these estuaries on the inner shelf foraminiferal fauna. The percentage distribution of this species...

Effects of CO2 hydrate on deep-sea foraminiferal assemblages

International Nuclear Information System (INIS)

Ricketts, E. R.; Kennett, J. P.; Hill, T. M.; Barry, J. P.

2005-01-01

This study, conducted with the Monterey Bay Aquarium Research Institute (MBARI), is the first to investigate potential effects of carbon dioxide (CO2) hydrates on benthic microfossils, specifically oraminifera. The experiment was conducted in September 2003 aboard the R/V Western Flier using the ROV Tiburon. Experimental (CO2 exposed) and control cores were collected at 3600m and stained to distinguish live (stained) from dead (unstained) individuals. Foraminifera are ideal for these investigations because of differing test composition (calcareous and agglutinated) and thickness, and diverse epifaunal and infaunal depth preferences. The effects of the CO2 on assemblages have been tracked both vertically (10cm depth) and horizontally, and between live and dead individuals. Increased mortality and dissolution of calcareous forms resulted from exposure to CO2 hydrate. Preliminary results suggest several major effects on surface sediment assemblages: 1) total number of foraminifera in a sample decreases; 2) foraminiferal diversity decreases in both stained and unstained specimens. The number of planktonic and hyaline calcareous tests declines greatly, with milliolids being more resistant to dissolution when stained; and 3) percentage of stained (live) forms is higher. Down-core trends (up to 10cm) indicate: 1) percent agglutinated forms decline and calcareous forms increasingly dominate; 2) agglutinated diversity decreases with depth; and 3) assemblages become increasingly similar with depth to those in control cores not subjected to CO2 hydrate. These results imply almost complete initial mortality and dissolution upon CO2 hydrate emplacement in the corrals. (Author)

Synchrotron X-ray microscopy of marine calcifiers: how plankton record past climate change

International Nuclear Information System (INIS)

Redfern, S A T; Branson, O; Read, E

2017-01-01

We have used STXM and PEEM to reveal the underpinning chemistry and nanoscale structure behind palaeo-climate geochemical signatures, such as trace Mg in shells- proposed proxies for palaeo-ocean temperature. This has allowed us to test the chemical assumptions and mechanisms underpinning the use of such empirical proxies. We have determined the control on driving chemical variations in biogenic carbonates using STXM at the absorption edge of Mg, B, and Na in the shells of modern plankton. The power of these observations lies in their ability to link changes in chemistry, microstructure, and growth process in biogenic carbonate to environmental influences. We have seen that such changes occur at length scales of tens of nanometres and demonstrated that STXM provides an invaluable route to understanding chemical environment and key heterogeneity at the appropriate length scale. This new understanding provides new routes for future measurements of past climate variation in the sea floor fossil record. (paper)

Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

Directory of Open Access Journals (Sweden)

F. Siddika

2012-06-01

Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

Fluctuation in glacial and interglacial sediment discharge of the River Indus as seen in the core from the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Guptha, M.V.S.; Hashimi, N.H.

Sediment core from the upper continental slope off Saurashtra Coast has been analysed for CaCO sub(3) and coarse fraction contents in addition to planktonic foraminifera and clay mineralogy. Based on CaCO sub(3) and planktonic foraminiferal data a...

Double Trouble Foraminiferal Calcification in a Changing Ocean

NARCIS (Netherlands)

Van Dijk, I.E.Y.

2017-01-01

Within the project ‘Double Trouble: Foraminiferal Calcification in a Changing Ocean’, I tried to illuminate mechanisms determining element incorporation in foraminifera with different calcification strategies. In particular, I aimed to assess the interplay between ocean acidification and

Double Trouble : Foraminiferal calcification in a changing ocean

NARCIS (Netherlands)

van Dijk, I.E.Y.

2017-01-01

Within the project ‘Double Trouble: Foraminiferal Calcification in a Changing Ocean’, I tried to illuminate mechanisms determining element incorporation in foraminifera with different calcification strategies. In particular, I aimed to assess the interplay between ocean acidification and

The predictive skill of species distribution models for plankton in a changing climate

DEFF Research Database (Denmark)

Brun, Philipp Georg; Kiørboe, Thomas; Licandro, Priscilla

2016-01-01

Statistical species distribution models (SDMs) are increasingly used to project spatial relocations of marine taxa under future climate change scenarios. However, tests of their predictive skill in the real-world are rare. Here, we use data from the Continuous Plankton Recorder program, one...... null models, is essential to assess the robustness of projections of marine planktonic species under climate change...

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

International Nuclear Information System (INIS)

Eynaud, Frederique

2011-01-01

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; δ 18 O, δ 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.

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.

Benthic foraminiferal census data from Mobile Bay, Alabama--counts of surface samples and box cores

Science.gov (United States)

Richwine, Kathryn A.; Osterman, Lisa E.

2012-01-01

A study was undertaken in order to understand recent environmental change in Mobile Bay, Alabama. For this study a series of surface sediment and box core samples was collected. The surface benthic foraminiferal data provide the modern baseline conditions of the bay and can be used as a reference for changing paleoenvironmental parameters recorded in the box cores. The 14 sampling locations were chosen in the bay to cover the wide diversity of fluvial and marine-influenced environments on both sides of the shipping channel.

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...

Comprehensive model of annual plankton succession based on the whole-plankton time series approach.

Directory of Open Access Journals (Sweden)

Jean-Baptiste Romagnan

Full Text Available Ecological succession provides a widely accepted description of seasonal changes in phytoplankton and mesozooplankton assemblages in the natural environment, but concurrent changes in smaller (i.e. microbes and larger (i.e. macroplankton organisms are not included in the model because plankton ranging from bacteria to jellies are seldom sampled and analyzed simultaneously. Here we studied, for the first time in the aquatic literature, the succession of marine plankton in the whole-plankton assemblage that spanned 5 orders of magnitude in size from microbes to macroplankton predators (not including fish or fish larvae, for which no consistent data were available. Samples were collected in the northwestern Mediterranean Sea (Bay of Villefranche weekly during 10 months. Simultaneously collected samples were analyzed by flow cytometry, inverse microscopy, FlowCam, and ZooScan. The whole-plankton assemblage underwent sharp reorganizations that corresponded to bottom-up events of vertical mixing in the water-column, and its development was top-down controlled by large gelatinous filter feeders and predators. Based on the results provided by our novel whole-plankton assemblage approach, we propose a new comprehensive conceptual model of the annual plankton succession (i.e. whole plankton model characterized by both stepwise stacking of four broad trophic communities from early spring through summer, which is a new concept, and progressive replacement of ecological plankton categories within the different trophic communities, as recognised traditionally.

The effects of the Sea Empress oil spill on the plankton of the Southern Irish Sea

International Nuclear Information System (INIS)

Batten, S.D.; Allen, R.J.S.; Wotton, C.O.M.

1998-01-01

This study investigates the effects of the Sea Empress oil spill on the local plankton communities which are an important component of the marine ecosystem. The Continuous Plankton Recorder survey has monitored the plankton in this area since 1970 giving an extensive time series for comparison with post-spill samples. The analytical procedures applied and results obtained are presented and reveal that, with some exceptions, no significant effects were evident. Barnacle larvae were not recorded post-spill and the spring zooplankton community was somewhat different to the previous year. A long-term trend is apparent in the community but the most common taxa showed no significant changes, suggesting a minor shift in species composition rather than a dramatic change. (author)

Foraminiferal and radiolarian biostratigraphy of the youngest (Late Albian through Late Cenomanian) sediments of the Tatra massif, Central Western Carpathians

Science.gov (United States)

Bąk, Krzysztof; Bąk, Marta

2013-06-01

Bąk, K. and Bąk M. 2013. Foraminiferal and radiolarian biostratigraphy of the youngest (Late Albian through Late Cenomanian) sediments of the Tatra massif, Central Western Carpathians. Acta Geologica Polonica, 63 (2), 223-237. Warszawa. The foraminiferal and radiolarian biostratigraphy of selected sections of the Zabijak Formation, the youngest sediments of the Tatra massif (Central Western Carpathians), have been studied. Benthic foraminifers, mainly agglutinated species, occur abundantly and continuously throughout the studied succession, while planktic foraminifers are generally sparse. Five planktic and two benthic foraminiferal zones have been recognized. The marly part of the Zabijak Formation comprises the Pseudothalmanninella ticinensis (Upper Albian) through the Rotalipora cushmani (Upper Cenomanian) planktic foraminiferal zones, and the Haplophragmoides nonioninoides and Bulbobaculites problematicus benthic foraminiferal zones. The radiolarians were recognized exclusively in the Lower Cenomanian part of the formation.

A 60-year ocean colour data set from the continuous plankton recorder

KAUST Repository

Raitsos, Dionysios E.

2012-11-20

The phytoplankton colour index (PCI) of the Continuous Plankton Recorder (CPR) survey is an in situ measure of ocean colour, which is considered a proxy of the phytoplankton biomass. PCI has been extensively used to describe the major spatiotemporal patterns of phytoplankton in the North Atlantic Ocean and North Sea since 1931. Regardless of its wide application, the lack of an adequate evaluation to test the PCI\\'s quantitative nature is an important limitation. To address this concern, a field trial over the main production season has been undertaken to assess the numerical values assigned by previous investigations for each category of the greenness of the PCI. CPRs were towed across the English Channel from Roscoff to Plymouth consecutively for each of 8 months producing 76 standard CPR samples, each representing 10 nautical miles of tow. The results of this experiment test and update the PCI methodology, and confirm the validity of this long-term in situ ocean colour data set. In addition, using a 60-year time series of the PCI of the western English Channel, a comparison is made between the previous and the current revised experimental calculations of PCI. © 2012 The Author 2012. Published by Oxford University Press. All rights reserved.

A 60-year ocean colour data set from the continuous plankton recorder

KAUST Repository

Raitsos, Dionysios E.; Walne, Anthony W.; Lavender, Sam; Licandro, Priscilla; Reid, Philip Chris; Edwards, Martin

2012-01-01

The phytoplankton colour index (PCI) of the Continuous Plankton Recorder (CPR) survey is an in situ measure of ocean colour, which is considered a proxy of the phytoplankton biomass. PCI has been extensively used to describe the major spatiotemporal patterns of phytoplankton in the North Atlantic Ocean and North Sea since 1931. Regardless of its wide application, the lack of an adequate evaluation to test the PCI's quantitative nature is an important limitation. To address this concern, a field trial over the main production season has been undertaken to assess the numerical values assigned by previous investigations for each category of the greenness of the PCI. CPRs were towed across the English Channel from Roscoff to Plymouth consecutively for each of 8 months producing 76 standard CPR samples, each representing 10 nautical miles of tow. The results of this experiment test and update the PCI methodology, and confirm the validity of this long-term in situ ocean colour data set. In addition, using a 60-year time series of the PCI of the western English Channel, a comparison is made between the previous and the current revised experimental calculations of PCI. © 2012 The Author 2012. Published by Oxford University Press. All rights reserved.

The foraminiferal-bacterial connection : an interdisciplinary study of meiofaunal behaviour in the deeper marine redox zone

NARCIS (Netherlands)

Langezaal, A.M.

2003-01-01

In this thesis-research the foraminiferal- bacterial interaction was addressed in several experimental studies as well as in a field study. We aimed at developing an experimental setting that is suitable for both foraminiferal and bacterial research. We also aimed at obtaining more insight in the

Bioprospecting Marine Plankton

Directory of Open Access Journals (Sweden)

Chris Bowler

2013-11-01

Full Text Available The ocean dominates the surface of our planet and plays a major role in regulating the biosphere. For example, the microscopic photosynthetic organisms living within provide 50% of the oxygen we breathe, and much of our food and mineral resources are extracted from the ocean. In a time of ecological crisis and major changes in our society, it is essential to turn our attention towards the sea to find additional solutions for a sustainable future. Remarkably, while we are overexploiting many marine resources, particularly the fisheries, the planktonic compartment composed of zooplankton, phytoplankton, bacteria and viruses, represents 95% of marine biomass and yet the extent of its diversity remains largely unknown and underexploited. Consequently, the potential of plankton as a bioresource for humanity is largely untapped. Due to their diverse evolutionary backgrounds, planktonic organisms offer immense opportunities: new resources for medicine, cosmetics and food, renewable energy, and long-term solutions to mitigate climate change. Research programs aiming to exploit culture collections of marine micro-organisms as well as to prospect the huge resources of marine planktonic biodiversity in the oceans are now underway, and several bioactive extracts and purified compounds have already been identified. This review will survey and assess the current state-of-the-art and will propose methodologies to better exploit the potential of marine plankton for drug discovery and for dermocosmetics.

Holocene environmental and parasequence development of the St. Jones Estuary, Delaware (USA): Foraminiferal proxies of natural climatic and anthropogenic change

Science.gov (United States)

Leorri, E.; Martin, R.; McLaughlin, P.

2006-01-01

The benthic foraminiferal record of marshes located along western Delaware Bay (St. Jones Estuary, USA) reflects the response of estuaries to sea-level and paleoclimate change during the Holocene. System tracts are recognized and within them parasequences based on sedimentological and foraminiferal assemblages identification. The parasequences defined by foraminiferal assemblages appear correlative with rapid Holocene climate changes that are of worldwide significance: 6000-5000, 4200-3800, 3500-2500, 1200-1000, and 600??cal years BP. Following postglacial sea-level rise, modern subestuaries and marshes in the region began to develop between 6000 and 4000??years BP, depending on their proximity to the mouth of Delaware Bay and coastal geomorphology. Initial sediments were fluvial in origin, with freshwater marshes established around 4000??years BP. The subsequent sea-level transgression occurred sufficiently slowly that freshwater marshes alternated with salt marshes at the same sites to around 3000??years BP. Locally another two transgressions are identified at 1800 and 1000??years BP respectively. Marine influence increased in the estuaries until 600??years BP (Little Ice Age), when regression occurred. Sea-level began to rise again during the mid-19th Century at the end of the Little Ice Age, when marshes became established. The presence of a sand lens in the upper and middle estuary and the reduction in the number of tests in the top samples in cores from the same area also suggest an anthropogenic influence. The estuary infill resulted in a sharp transgressive sequence, represented by salt marsh foraminiferal assemblages in the upper part of the cores. The increase in marsh foraminifera in both areas suggests an increase in marine influence that might be due to the transgression beginning at the end of the Little Ice Age about 150-180??years ago coupled with anthropogenic straightening of the channel in 1913. ?? 2006 Elsevier B.V. All rights reserved.

The latest Paleocene benthic extinction event: Punctuated turnover in outer neritic benthic foraminiferal faunas from Gebel Aweina, Egypt

OpenAIRE

Speijer, Robert; Schmitz, B; Aubry, MP; Charisi, SD

1995-01-01

We investigated the benthic foraminiferal record of the neritic sequence at Gebel Aweina (Nile Valley, Egypt) in relation to the latest Paleocene deep-sea benthic extinction event (BEE). At Gebel Aweina an expanded sequence, spanning calcareous nannofossil Zones NP8-NPlO, is continuously exposed and yields calcareous microfauna throughout. The BEE level is situated about halfway through Zone NP9 at 17m above the base of the Esna Formation. Detailed biostratigraphic and isotopic studies have i...

Common species link global ecosystems to climate change: dynamical evidence in the planktonic fossil record.

Science.gov (United States)

Hannisdal, Bjarte; Haaga, Kristian Agasøster; Reitan, Trond; Diego, David; Liow, Lee Hsiang

2017-07-12

Common species shape the world around us, and changes in their commonness signify large-scale shifts in ecosystem structure and function. However, our understanding of long-term ecosystem response to environmental forcing in the deep past is centred on species richness, neglecting the disproportional impact of common species. Here, we use common and widespread species of planktonic foraminifera in deep-sea sediments to track changes in observed global occupancy (proportion of sampled sites at which a species is present and observed) through the turbulent climatic history of the last 65 Myr. Our approach is sensitive to relative changes in global abundance of the species set and robust to factors that bias richness estimators. Using three independent methods for detecting causality, we show that the observed global occupancy of planktonic foraminifera has been dynamically coupled to past oceanographic changes captured in deep-ocean temperature reconstructions. The causal inference does not imply a direct mechanism, but is consistent with an indirect, time-delayed causal linkage. Given the strong quantitative evidence that a dynamical coupling exists, we hypothesize that mixotrophy (symbiont hosting) may be an ecological factor linking the global abundance of planktonic foraminifera to long-term climate changes via the relative extent of oligotrophic oceans. © 2017 The Authors.

Late Glacial–Holocene record of benthic foraminiferal ...

Indian Academy of Sciences (India)

K Verma

2018-03-06

Mar 6, 2018 ... influence of oxygen-rich Antarctic Intermediate Water (AAIW). Keywords. Paleontology; benthic ..... nent changes at millennial scale are noticed during certain intervals ...... become environmental change? The proxy record of ...

Extreme warmth and heat-stressed plankton in the tropics during the Paleocene-Eocene Thermal Maximum.

Science.gov (United States)

Frieling, Joost; Gebhardt, Holger; Huber, Matthew; Adekeye, Olabisi A; Akande, Samuel O; Reichart, Gert-Jan; Middelburg, Jack J; Schouten, Stefan; Sluijs, Appy

2017-03-01

Global ocean temperatures rapidly warmed by ~5°C during the Paleocene-Eocene Thermal Maximum (PETM; ~56 million years ago). Extratropical sea surface temperatures (SSTs) met or exceeded modern subtropical values. With these warm extratropical temperatures, climate models predict tropical SSTs >35°C-near upper physiological temperature limits for many organisms. However, few data are available to test these projected extreme tropical temperatures or their potential lethality. We identify the PETM in a shallow marine sedimentary section deposited in Nigeria. On the basis of planktonic foraminiferal Mg/Ca and oxygen isotope ratios and the molecular proxy [Formula: see text], latest Paleocene equatorial SSTs were ~33°C, and [Formula: see text] indicates that SSTs rose to >36°C during the PETM. This confirms model predictions on the magnitude of polar amplification and refutes the tropical thermostat theory. We attribute a massive drop in dinoflagellate abundance and diversity at peak warmth to thermal stress, showing that the base of tropical food webs is vulnerable to rapid warming.

Foraminiferal and seismic stratigraphy, paleoenvironments and depositional cycles in the Georges Bank Basin

Science.gov (United States)

Poag, C. W.

Biostratigraphic analyses of foraminiferal assemblages sampled from rotary cuttings taken at 10 ft to 90 ft intervals were used with interpretation of seismic sequences to determine the presence of nonconformities and to establish a chronostratigraphic framework for COST G-1 and G-2 wells. The chronostratigraphic sequences were then used to calculate sediment accumulation rates. Lithostratigraphic and chronostratigraphic units were compared with those of the Scotian Basin of Canada, and correlations were established between the COST G-2 and the Shell Mohican L-100 wells. Paleoenvironmental analysis was based on the microfossil record of the G-1 and G-2 wells and on interpretation of seismic facies along USGS multichannel line 19.

A new name for the foraminiferal genus Heterospira

NARCIS (Netherlands)

Umbgrove, J.H.F.

1937-01-01

A short time ago I described a new foraminiferal genus from the Tertiary of Borneo 1). I gave this genus the name of Heterospira. Mr. P. H. Oehser of Washington drew my attention to the fact that E. Koken as early as 1896²) had used the name Heterospira for a genus of triassic gastropoda from

Orbital-scale Central Arctic Ocean Temperature Records from Benthic Foraminiferal δ18O and Ostracode Mg/Ca Ratios

Science.gov (United States)

Keller, K.; Cronin, T. M.; Dwyer, G. S.; Farmer, J. R.; Poirier, R. K.; Schaller, M. F.

2017-12-01

Orbital-scale climate variability is often amplified in the polar region, for example in changes in seawater temperature, sea-ice cover, deep-water formation, ecosystems, heat storage and carbon cycling. Yet, the relationship between the Arctic Ocean and global climate remains poorly understood due largely to limited orbital-scale paleoclimate records, the complicated nature of sea-ice response to climate and limited abundance of deep sea biological proxies. Here we reconstruct central Arctic Ocean bottom temperatures over the last 600 kyr using ostracode Mg/Ca ratios (genus Krithe) and benthic foraminiferal oxygen isotope ratios (δ18Obf - I. teretis, O. tener, P. bulloides, C. reniforme, C. wuellerstorfi) in six sediment cores recovered from the Mendeleev and Northwind Ridges (700- 2726 m water depth). We examined glacial-interglacial cycles in Arctic seawater temperatures and Arctic δ18Obf chronostratigraphy to reconcile effects of changing bottom water temperature, ice volume and regional hydrography on δ18Obf records. Results show lower ( 10-12 mmol/mol) interglacial and higher ( 16-23 mmol/mol) glacial Mg/Ca ratios, signifying intermediate depth ocean warming during glacials of up to 2 ºC. These temperature maxima are likely related to a deepening of the halocline and the corresponding deeper influence of warm Atlantic water. Glacial-interglacial δ18Obf ranges are smaller in the Arctic ( 0.8-1‰ VPDB) than in the global ocean ( 1.8 ‰). However, when the distinct glacial-interglacial temperature histories of the Arctic (glacial warming) and global ocean (glacial cooling) are accounted for, both Arctic and global ocean seawater δ18O values (δ18Osw) exhibit similar 1.2-1.3 ‰ glacial-interglacial ranges. Thus, Arctic δ18Obf confirms glacial Arctic warming inferred from ostracode Mg/Ca. This study will discuss the strengths and limitations of applying paired Mg/Ca and oxygen isotope proxies in reconstructing more robust paleoceanographic changes in the

Origin of marine planktonic cyanobacteria.

Science.gov (United States)

Sánchez-Baracaldo, Patricia

2015-12-01

Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600-2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500-542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600-1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000-542 Mya).

The effects of the Sea Empress oil spill on the plankton of the southern Irish Sea

International Nuclear Information System (INIS)

Batten, S.; Allen, R.; Wotton, C.

1997-07-01

This report describes the methodology used to determine any effects of the Sea Empress oil spill on the plankton communities of the southern Irish Sea. The Continuous Plankton Recorder (CPR) survey has monitored the plankton in this area since 1970 so there is a long time series of data collected before the spill, almost 2000 samples, with which to compare the post-spill data. The analytical procedures applied and results obtained are presented and reveal that in the majority of cases no significant effects were evident. Some exceptions are also described. The results suggest that no further analysis of the plankton communities is necessary, unless other studies reveal that other marine habitats which may have an influence on the plankton of this area are continuing to display effects of the spill. There is scope for further investigation of the trends and events described in this report but this is outside the remit of the project. (author)

Foraminiferal survival after long term experimentally induced anoxia

Science.gov (United States)

Langlet, D.; Geslin, E.; Baal, C.; Metzger, E.; Lejzerowicz, F.; Riedel, B.; Zuschin, M.; Pawlowski, J.; Stachowitsch, M.; Jorissen, F. J.

2013-06-01

Anoxia has been successfully induced in four benthic chambers installed on the Northern Adriatic seafloor from 1 week to 10 months. To accurately determine whether benthic foraminifera can survive experimentally induced prolonged anoxia, the CellTrackerGreen method has been applied. Numerous individuals have been found living at all sampling times and at all sampling depths, showing that benthic foraminifera can survive up to 10 months of anoxia with co-occurring hydrogen sulphides. However, foraminiferal standing stocks decrease with sampling time in an irregular way. A large difference in standing stock between two cores samples in initial conditions indicates the presence of a large spatial heterogeneity of the foraminiferal faunas. An unexpected increase in standing stocks after 1 month is tentatively interpreted as a reaction to increased food availability due to the massive mortality of infaunal macrofaunal organisms. After this, standing stocks decrease again in a core sampled after 2 months of anoxia, to attain a minimum in the cores sampled after 10 months. We speculate that the trend of overall decrease of standing stocks is not due to the adverse effects of anoxia and hydrogen sulphides, but rather due to a continuous diminution of labile organic matter.

Millennial-scale plankton regime shifts in the subtropical North Pacific Ocean.

Science.gov (United States)

McMahon, Kelton W; McCarthy, Matthew D; Sherwood, Owen A; Larsen, Thomas; Guilderson, Thomas P

2015-12-18

Climate change is predicted to alter marine phytoplankton communities and affect productivity, biogeochemistry, and the efficacy of the biological pump. We reconstructed high-resolution records of changing plankton community composition in the North Pacific Ocean over the past millennium. Amino acid-specific δ(13)C records preserved in long-lived deep-sea corals revealed three major plankton regimes corresponding to Northern Hemisphere climate periods. Non-dinitrogen-fixing cyanobacteria dominated during the Medieval Climate Anomaly (950-1250 Common Era) before giving way to a new regime in which eukaryotic microalgae contributed nearly half of all export production during the Little Ice Age (~1400-1850 Common Era). The third regime, unprecedented in the past millennium, began in the industrial era and is characterized by increasing production by dinitrogen-fixing cyanobacteria. This picoplankton community shift may provide a negative feedback to rising atmospheric carbon dioxide concentrations. Copyright © 2015, American Association for the Advancement of Science.

Foraminiferal and carbon isotope stratigraphy through the Paleocene-Eocene transition at Dee Stream, Marlborough, New Zealand

International Nuclear Information System (INIS)

Hancock, H.J.L.; Dickens, G.R.; Strong, C.P.; Hollis, C.J.; Field, B.D.

2003-01-01

Dee Stream in the Clarence River valley of New Zealand bisects a well-exposed section of marine sedimentary rocks deposited in the Early Paleogene at high southern latitudes. One hundred metres of strata lying within this section and comprising cm-dm well-bedded, siliceous limestone with marly partings was mapped, logged, and sampled to establish a detailed foraminiferal and carbon isotope stratigraphy and to examine environmental changes across the Paleocene-Eocene thermal maximum (PETM). Although low abundance and poor preservation of planktic and benthic foraminifera characterises much of the Paleocene, foraminifera and carbon isotopes clearly show that the section spans the Upper Paleocene to Lower Eocene planktic foraminiferal zones from Zone P4 to Subzone P6b, and the Subbotina triloculinoides to Pseudohastigerina wilcoxensis Zones. The δ 13 C record correlates closely to other δ 13 C curves generated from other key Early Paleogene carbonate sequences. The Dee Stream logged section contains a 1 m thick PETM interval at 26.5 m at the base of Zone P5, or the Morozovella velascoensis Subzone. Here, benthic foraminifera undergo significant extinction, Morozovella aequa makes its first appearance, and the δ 13 C of carbonate decreases by 2 permille. The benthic foraminifer Bulimina tuxpamensis dominates benthic assemblages immediately following the onset of the PETM interval, suggesting dysoxic bottom waters during this event. In conjunction with other recently examined sections from the Marlborough region, the thick and apparently continuous Paleogene record at Dee Stream provides an important site for understanding environmental change on high-latitude continental margins during the Paleogene, including the PETM. (author). 54 refs., 10 figs., 2 tabs

Ecological Stoichiometry of Ocean Plankton

Science.gov (United States)

Moreno, Allison R.; Martiny, Adam C.

2018-01-01

Marine plankton elemental stoichiometric ratios can deviate from the Redfield ratio (106C:16N:1P); here, we examine physiological and biogeochemical mechanisms that lead to the observed variation across lineages, regions, and seasons. Many models of ecological stoichiometry blend together acclimative and adaptive responses to environmental conditions. These two pathways can have unique molecular mechanisms and stoichiometric outcomes, and we attempt to disentangle the two processes. We find that interactions between environmental conditions and cellular growth are key to understanding stoichiometric regulation, but the growth rates of most marine plankton populations are poorly constrained. We propose that specific physiological mechanisms have a strong impact on plankton and community stoichiometry in nutrient-rich environments, whereas biogeochemical interactions are important for the stoichiometry of the oligotrophic gyres. Finally, we outline key areas with missing information that is needed to advance understanding of the present and future ecological stoichiometry of ocean plankton.

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.

Kelimpahan dan Keanekaragaman Plankton di Perairan Selat Bali (Plankton Abundance and Diversity in the Bali Strait

Directory of Open Access Journals (Sweden)

Ruly Isfatul Khasanah

2013-12-01

Full Text Available Fitoplankton mempunyai peran sangat penting dalam suatu perairan, selain berada pada dasar rantai makanan sedangkan zooplankton merupakan herbivor pemangsanya. Penelitian mengenai kelimpahan dan keanekaragaman plankton di perairan Selat Bali dilakukan pada musim peralihan II (Nopember 2012 dan musim barat (Pebruari 2013. Penelitian bertujuan untuk mengamati perbedaan kelimpahan dan keanekaragaman plankton pada dua musim angin muson. Sampel air diambil dengan menggunakan water sampler sedangkan sampel plankton diambil secara horisontal dan vertikal  pada kedalaman 1 m dan 20 m dengan jaring plankton Kitahara bermata jaring 20 µm. Hasil pengukuran nutrien pada musim peralihan II memiliki kadar fosfat, nitrat, bahan organik, silikat dan klorofil-a lebih tinggi dibandingkan pada musim barat. Informasi tersebut memperkuat indikasi adanya perpindahan massa air dari lapisan yang lebih dalam ke lapisan yang lebih dangkal. Nutrien fosfat dan nitrat diperlukan untuk mempertahankan fungsi membran sel dan silikia dibutuhkan untuk pembentukan dinding sel terutama pada diatom. Hasil penelitian juga menunjukkan bahwa kelas diatom (Bacillariophyceae mencapai 95,9 % dari total jenis dan kelimpahan fitoplankton seluruh stasiun penelitian, sisanya berasal dari genus Dinophyceae. Kelimpahan fitoplankton tertinggi terjadi pada musim peralihan II dengan Rhizosolenia stolterfothii sebesar 51.405 sel.L-1 (80,1%, sedangkan pada musim barat copepoda ditemukan melimpah sebesar 8.178 ind.L-1 (88,3 %. Hasil ini mengindikasikan bahwa dengan kelimpahan plankton yang ditemukan perairan Selat Bali dinilai cukup potensial untuk mendukung kehidupan biota laut pelagis. Kata kunci: plankton, selat Bali, rhizosolenia stolterfothii, muson   Abstract Phytoplankton has important role as primary producer in the sea and act as base of food chain while zooplankton act as herbivore prey on them. Research on abundance and diversity of plankton at Bali Strait was performed during

Plankton bloom controlled by horizontal stirring

Science.gov (United States)

McKiver, W.; Neufeld, Z.; Scheuring, I.

2009-10-01

Here we show a simple mechanism in which changes in the rate of horizontal stirring by mesoscale ocean eddies can trigger or suppress plankton blooms and can lead to an abrupt change in the average plankton density. We consider a single species phytoplankton model with logistic growth, grazing and a spatially non-uniform carrying capacity. The local dynamics have multiple steady states for some values of the carrying capacity that can lead to localized blooms as fluid moves across the regions with different properties. We show that for this model even small changes in the ratio of biological timescales relative to the flow timescales can greatly enhance or reduce the global plankton productivity. Thus, this may be a possible mechanism in which changes in horizontal mixing can trigger plankton blooms or cause regime shifts in some oceanic regions. Comparison between the spatially distributed model and Lagrangian simulations considering temporal fluctuations along fluid trajectories, demonstrates that small scale transport processes also play an important role in the development of plankton blooms with a significant influence on global biomass.

Foraminiferal Range Expansions: The Mediterranean Sea as a natural laboratory for climate induced invasions

Science.gov (United States)

Hortense Mouanga, Gloria; Langer, Martin R.

2015-04-01

Climate change and biological invasions are key processes that modify biodiversity. One of the most severely affected areas of global change is the Mediterranean Sea, where global warming and the opening of the Suez Canal triggered a mass invasion of tropical Red Sea taxa into Mediterranean territories. Climate models prognosticate that the Mediterranean Sea will be one of the most affected ocean regions and may thus serve as a natural laboratory of future global changes. Among the key taxa that are rapidly expanding their latitudinal range in the Mediterranean Sea are symbiont-bearing foraminifera of the genus Amphistegina. Their range expansion strongly correlates with rising sea surface temperatures and mirrors processes of global change. Amphisteginid foraminifera are among the most prolific foraminiferal species and contribute significantly to shallow-water carbonate sediments. Given their prominent environmental role, rapid biogeographic range expansion, and impact on native ecosystems, amphisteginid range expansion and invasion into new territory are likely to trigger changes in ecosystem functioning. Among the uncertainties, it is not known whether all parts of the Mediterranean will be affected equally and to what extent amphisteginid invasions will impact native biotas. We have initiated a new baseline study to explore the effects of invasive amphisteginids on native foraminiferal biotas and to monitor expansion rates and effects on ecosystem functioning along the current range expansion front. We will present new data on recent shift along the range expansion front and discuss cascading effects on community structures and species richness of native foraminiferal biotas. The magnitude and effects that climate change will have on the Mediterranean foraminiferal faunas may ultimately serve as an example of what would happen along expansion fronts in global oceans.

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)

What is the Right Temperature Sensitivity for Foraminiferal Mg/ca Paleothermometry in Ancient Oceans?

Science.gov (United States)

Eggins, S.; Holland, K.; Hoenisch, B.; Spero, H. J.; Allen, K. A.

2013-12-01

Mg/Ca seawater thermometry has become a cornerstone of modern paleoceanography. Laboratory experiments, seafloor core-top samples, plankton trap and tow collected materials all indicate consistent temperature sensitivity (9-10% increase in Mg/Ca per °C) for a full range of modern planktic foraminifer species. While these results demonstrate the overall robustness of Mg/Ca paleothermometry for the modern ocean, it is an empirical tool for which there is limited understanding of its bio-physio-chemical basis and its applicability to ancient oceans. We have undertaken experimental cultures of Orbulina universa, Globigerinoides sacculifer and Globigerinoides ruber (pink) across a range of seawater compositions (temperature, carbonate chemistry and Mg/Casw) that encompass modern and ancient Paleogene and Cretaceous ocean compositions (Mg/Casw 0.25x to 2x modern and pCO2 = 200 to 1500 ppmv). Our results reveal that the sensitivity of the Mg/Ca-thermometer for planktic foraminifers reduces significantly with Mg/Casw, rather than remaining constant as has been widely assumed or, increasing at lower Mg/Casw as proposed recently by Evans and Müller (2012). These results indicate that the modern sensitivity of 9-10% increase in Mg/Ca per °C cannot yet be applied to obtain reliable relative temperature change estimates to ancient oceans. These results further suggest that variations in foraminiferal Mg/Ca compositions in ancient oceans with lower Mg/Casw may correspond to larger temperature variations than in the modern ocean. Evans D. and Müller W., Paleoceanography, vol. 27, PA4205, doi:10.1029/2012PA002315, 2012

Factors driving the seasonal distribution of planktonic and epiphytic ciliates in a eutrophicated Mediterranean Lagoon

Energy Technology Data Exchange (ETDEWEB)

Dhib, Amel [Université de Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS 6249 (France); Institut National des Sciences et Technologies de la Mer (INSTM), Laboratoire Milieu Marin, Centre la Goulette (Tunisia); Brahim, Mounir Ben; Ziadi, Boutheina; Akrout, Fourat; Turki, Souad [Institut National des Sciences et Technologies de la Mer (INSTM), Laboratoire Milieu Marin, Centre la Goulette (Tunisia); Aleya, Lotfi [Université de Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS 6249 (France)

2013-09-15

Highlights: • Distribution of planktonic and epiphytic ciliates at five stations in Ghar El Melh Lagoon. • 28 planktonic ciliates were identified with spring-early autumn peaks. • 4 epiphytic ciliates of the seagrass Ruppia cirrhosa were recorded with high density. • Significant correlations were found between ciliate assemblages, environmental factors and harmful dinoflagellates. -- Abstract: We studied the distribution of planktonic and epiphytic ciliates coupled with environmental factors and microalgae abundance at five stations in Ghar El Melh Lagoon (Tunisia). Planktonic ciliates were monitored for a year and epiphytic ciliates were sampled during summer 2011 in concordance with the proliferation of the seagrass Ruppia cirrhosa. Ciliate assemblage was largely dominated by Spirotrichea followed respectively by Tintinnida of and Strombidiida. No significant difference was found in the distribution of ciliate species among the stations. Redundancy analysis indicates that abiotic factors (temperature and nutriments) have a significant effect on the dynamics of certain ciliates. For epiphytic ciliates, 4 species were identified: Tintinnopsis campanula, Aspidisca sp., Strombidium acutum and Amphorides amphora. Based on PERMANOVA analyses, ciliates exhibit significant correlations among months and stations. According to ACP, epiphyte distribution follows roughly those of R. cirrhosa and pH. Significant correlations were found between harmful dinoflagellates and both planktonic and epiphytic ciliates.

Factors driving the seasonal distribution of planktonic and epiphytic ciliates in a eutrophicated Mediterranean Lagoon

International Nuclear Information System (INIS)

Dhib, Amel; Brahim, Mounir Ben; Ziadi, Boutheina; Akrout, Fourat; Turki, Souad; Aleya, Lotfi

2013-01-01

Highlights: • Distribution of planktonic and epiphytic ciliates at five stations in Ghar El Melh Lagoon. • 28 planktonic ciliates were identified with spring-early autumn peaks. • 4 epiphytic ciliates of the seagrass Ruppia cirrhosa were recorded with high density. • Significant correlations were found between ciliate assemblages, environmental factors and harmful dinoflagellates. -- Abstract: We studied the distribution of planktonic and epiphytic ciliates coupled with environmental factors and microalgae abundance at five stations in Ghar El Melh Lagoon (Tunisia). Planktonic ciliates were monitored for a year and epiphytic ciliates were sampled during summer 2011 in concordance with the proliferation of the seagrass Ruppia cirrhosa. Ciliate assemblage was largely dominated by Spirotrichea followed respectively by Tintinnida of and Strombidiida. No significant difference was found in the distribution of ciliate species among the stations. Redundancy analysis indicates that abiotic factors (temperature and nutriments) have a significant effect on the dynamics of certain ciliates. For epiphytic ciliates, 4 species were identified: Tintinnopsis campanula, Aspidisca sp., Strombidium acutum and Amphorides amphora. Based on PERMANOVA analyses, ciliates exhibit significant correlations among months and stations. According to ACP, epiphyte distribution follows roughly those of R. cirrhosa and pH. Significant correlations were found between harmful dinoflagellates and both planktonic and epiphytic ciliates

Paleoclimatic changes occurred during the last two centuries in the Gulf of Gaeta (central-eastern Tyrrhenian Sea): a contribution of NEXTDATA project

Science.gov (United States)

Lirer, Fabrizio; Vallefuoco, Mattia; Albertazzi, Sonia; Anzalone, Erlisiana; Bellucci, Luca; Bonomo, Sergio; Capotondi, Lucilla; Cascella, Antonio; Di Rita, Federico; Ferraro, Luciana; Florindo, Fabio; Giuliani, Silvia; Domenica Insinga, Donatella; Lurcock, Pont; Magri, Donatella; Margaritelli, Giulia; Marsella, Ennio; Petrosino, Paola; Sprovieri, Mario; Sorgato, Stefania

2014-05-01

A high-resolution integrated study, which includes tephrochronology (tefra layer associated to 1906 AD Vesuvius event) and radionuclide dating method (210Pb and 137Cs), has been performed in a super-expanded marine record (sedimentation rate of 0.47 cm/yr) from the continental shelf of the Gulf of Gaeta (central eastern Tyrrhenian Sea). Planktonic foraminifera, calcareous nannofossils, pollens and oxygen stable isotope data performed on Globigerinoides ruber, revealed environmental changes occurred during the last two centuries. In detail we recognise four paleoclimatic changes. From ca. 1800 to ca. 1865 AD, d18O G. ruber signal combined with evidences of abundance increase of planktonic foraminifera Globoratialia inflata and G. truncatulinoides and of calcareous nannofossils Emiliana huxley document cold-temperate phase. Between ca. 1865 and ca. 1882 AD, d18O G. ruber record document a short warm interval associated with a turnover from carnivorous to herbivorous-opportunistic planktonic foraminiferal species and an increase in abundance of calcareous nannofossil Florisphaera profunda. At ca. 1935 AD, d18O G. ruber data indicate a gradually warming, concomitant an evident turnover from carnivorous to herbivorous-opportunistic planktonic foraminiferal species, and associated to the increase of calcareous nannofossil F. profunda. From ca. 1950 AD to the present day the warm phase documents a further strong increase in G. ruber alba, G. quadrilobatus and F. profunda abundances. The pollen analysis carried out on the same core revealed a two-step increase in arboreal vegetation, this is mostly related to a rise of Olea, Quercus evergreen and riparian trees (Alnus and Salix) from ca. 1882 AD, and increase in conifers (Pinus and Cupressaceae) from ca. 1980 AD. The short lived warm interval documented by d18O between ca. 1865 and ca. 1882 AD may triggered the increase in Olea and the coeval general decrease in deciduous trees. Among herbs, Cyperaceae, along with ferns

Planktonic interactions and chaotic advection in Langmuir circulation

DEFF Research Database (Denmark)

Bees, Martin Alan; Mezic, I.; McGlade, J.

1998-01-01

The role of unsteady laminar flows for planktonic communities is investigated. Langmuir circulation is used, as a typical medium-scale structure, to illustrate mechanisms for the generation of plankton patches. Two behaviours are evident: chaotic regions that help to spread plankton and locally...

Last Glacial to Holocene changes of deep and intermediate water carbonate ion concentrations in the Southern Ocean: constraints from foraminiferal Boron/Calcium ratios

OpenAIRE

Kersten, Franziska

2013-01-01

In this thesis, the first records of intermediate and deep water carbonate ion concentrations in the South Pacific were generated in order to study carbon cycle dynamics throughout the past 30,000 years. Benthic foraminiferal B/Ca, an indicator of past seawater carbonate ion saturation is the main paleoceanographic proxy that was used in this study. Down-core proxy studies carried out within the scope of this thesis were used to address currently unresolved questions about the origin, mechani...

Composition of planktonic organisms and its associated physico ...

African Journals Online (AJOL)

Composition of plankton communities in two ponds at African Regional Agriculture Centre (ARAC) Aluu, Port Harcourt was undertaken between May and June 2004, to assess the composition, relative abundance and distribution of plankton. The diversity of plankton was poor. Twenty-eight taxa representing four (4) families ...

Planktonic Euryarchaeota are a significant source of archaeal tetraether lipids in the ocean.

Science.gov (United States)

Lincoln, Sara A; Wai, Brenner; Eppley, John M; Church, Matthew J; Summons, Roger E; DeLong, Edward F

2014-07-08

Archaea are ubiquitous in marine plankton, and fossil forms of archaeal tetraether membrane lipids in sedimentary rocks document their participation in marine biogeochemical cycles for >100 million years. Ribosomal RNA surveys have identified four major clades of planktonic archaea but, to date, tetraether lipids have been characterized in only one, the Marine Group I Thaumarchaeota. The membrane lipid composition of the other planktonic archaeal groups--all uncultured Euryarchaeota--is currently unknown. Using integrated nucleic acid and lipid analyses, we found that Marine Group II Euryarchaeota (MG-II) contributed significantly to the tetraether lipid pool in the North Pacific Subtropical Gyre at shallow to intermediate depths. Our data strongly suggested that MG-II also synthesize crenarchaeol, a tetraether lipid previously considered to be a unique biomarker for Thaumarchaeota. Metagenomic datasets spanning 5 y indicated that depth stratification of planktonic archaeal groups was a stable feature in the North Pacific Subtropical Gyre. The consistent prevalence of MG-II at depths where the bulk of exported organic matter originates, together with their ubiquitous distribution over diverse oceanic provinces, suggests that this clade is a significant source of tetraether lipids to marine sediments. Our results are relevant to archaeal lipid biomarker applications in the modern oceans and the interpretation of these compounds in the geologic record.

Benthic ecological mapping of the Ayeyarwady delta shelf off Myanmar, using foraminiferal assemblages

Digital Repository Service at National Institute of Oceanography (India)

Panchang, R.; Nigam, R.

Information on benthic ecologies is a prerequisite to evaluate marine resources, their management and monitoring the impact arising from their exploitation. In the present study, benthic foraminiferal distributions from 124 surface sediment samples...

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.

This study focused on planktic foraminifera in plankton tows and surface sediments from the western Indian sector of Southern Ocean in order to evaluate the potential foraminiferal secondary calcification and/or dissolution in the sediment...

Sherborn's foraminiferal studies and their influence on the collections at the Natural History Museum, London.

Science.gov (United States)

Miller, C Giles

2016-01-01

Sherborn's work on the Foraminifera clearly provided the initial spark to compile the major indexes for which he is famous. Contact and help from famous early micropalaeontologists such as T. Rupert Jones and Fortescue William Millett led Sherborn to produce his Bibliography of Foraminifera and subsequently a two-part Index of Foraminiferal Genera and Species. Edward Heron-Allen, whose mentor was Millett, was subsequently inspired by the bibliography to attempt to acquire every publication listed. This remarkable collection of literature was donated to the British Museum (Natural History) in 1926 along with the foraminiferal collections Heron-Allen had mainly purchased from early micropalaeontologists. This donation forms the backbone of the current NHM micropalaeontological collections. The NHM collections contain a relatively small amount of foraminiferal material published by Sherborn from the London Clay, Kimmeridge Clay and Speeton Clay. Another smaller collection reflects his longer-term interest in the British Chalk following regular fieldwork with A. W. Rowe. Other collections relating to Sherborn's early published work, particularly with T. R. Jones, are not present in the collections but these collections may have been sold or deposited elsewhere by his co-workers.

Plankton food-webs: to what extent can they be simplified?

Directory of Open Access Journals (Sweden)

Domenico D'Alelio

2016-05-01

Full Text Available Plankton is a hugely diverse community including both unicellular and multicellular organisms, whose individual dimensions span over seven orders of magnitude. Plankton is a fundamental part of biogeochemical cycles and food-webs in aquatic systems. While knowledge has progressively accumulated at the level of single species and single trophic processes, the overwhelming biological diversity of plankton interactions is insufficiently known and a coherent and unifying trophic framework is virtually lacking. We performed an extensive review of the plankton literature to provide a compilation of data suitable for implementing food-web models including plankton trophic processes at high taxonomic resolution. We identified the components of the plankton community at the Long Term Ecological Research Station MareChiara in the Gulf of Naples. These components represented the sixty-three nodes of a plankton food-web. To each node we attributed biomass and vital rates, i.e. production, consumption, assimilation rates and ratio between autotrophy and heterotrophy in mixotrophic protists. Biomasses and rates values were defined for two opposite system’s conditions; relatively eutrophic and oligotrophic states. We finally identified 817 possible trophic links within the web and provided each of them with a relative weight, in order to define a diet-matrix, valid for both trophic states, which included all consumers, fromn anoflagellates to carnivorous plankton. Vital rates for plankton resulted, as expected, very wide; this strongly contrasts with the narrow ranges considered in plankton system models implemented so far. Moreover, the amount and variety of trophic links highlighted by our review is largely excluded by state-of-the-art biogeochemical and food-web models for aquatic systems. Plankton models could potentially benefit from the integration of the trophic diversity outlined in this paper: first, by using more realistic rates; second, by better

De scheiding van slib en plankton

NARCIS (Netherlands)

Budding, M.C.

1974-01-01

It is possible to separate non-living suspended matter and living plankton with the help of a common laboratory centrifuge and a commercial silica-gel called LUDOX. With this method it becomes possible to determine particle size of suspended matter and plankton separately with e.g. a Coulter

Benthic foraminiferal assemblages as bio-indicators of metals contamination in sediments, Qarun Lake as a case study, Egypt

Science.gov (United States)

Abd El Naby, Ahmed; Al Menoufy, Safia; Gad, Ahmed

2018-03-01

Qarun Lake, in the Fayoum Depression of the Western Desert of Egypt, lies within the deepest area in the River Nile flood plain. The drainage water in the Qarun Lake is derived from the discharge of the natural and artificial drainage systems in the Fayoum. Mixed domestic and agricultural pollutants, including heavy metals, nitrates, phosphates, sulfates and pesticides, are discharged into Qarun Lake. Forty-six samples, collected from the undisturbed layer of sediments were used for benthic foraminiferal analysis. Concentrations of some selected trace metal elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V, and Zn) were also determined. Statistical analysis of the abiotic variables (Texture distribution of sediments, Physico-chemical parameters, and metals concentrations) and of the biotic variables (distribution of benthic foraminiferal species) were also performed. The Q-mode cluster analysis of benthic foraminiferal distribution has provided evidence that the Qarun Lake can be subdivided into two cluster groups (A and B), reflecting environmental changes in the lake ecosystem. Cluster B can also be subdivided into two sub-clusters (B1 and B2). The presence of only pollution tolerant taxa with higher faunal density and lower diversity and the absence of the other foraminiferal assemblages in cluster A were attributed to the high concentration of trace metal elements and the strong environmental stress at the eastern and central parts of the Qarun Lake.

Effectiveness of benthic foraminiferal and coral assemblages as water quality indicators on inshore reefs of the Great Barrier Reef, Australia

Science.gov (United States)

Uthicke, S.; Thompson, A.; Schaffelke, B.

2010-03-01

Although the debate about coral reef decline focuses on global disturbances (e.g., increasing temperatures and acidification), local stressors (nutrient runoff and overfishing) continue to affect reef health and resilience. The effectiveness of foraminiferal and hard-coral assemblages as indicators of changes in water quality was assessed on 27 inshore reefs along the Great Barrier Reef. Environmental variables (i.e., several water quality and sediment parameters) and the composition of both benthic foraminiferal and hard-coral assemblages differed significantly between four regions (Whitsunday, Burdekin, Fitzroy, and the Wet Tropics). Grain size and organic carbon and nitrogen content of sediments, and a composite water column parameter (based on turbidity and concentrations of particulate matter) explained a significant amount of variation in the data (tested by redundancy analyses) in both assemblages. Heterotrophic species of foraminifera were dominant in sediments with high organic content and in localities with low light availability, whereas symbiont-bearing mixotrophic species were dominant elsewhere. A similar suite of parameters explained 89% of the variation in the FORAM index (a Caribbean coral reef health indicator) and 61% in foraminiferal species richness. Coral richness was not related to environmental setting. Coral assemblages varied in response to environmental variables, but were strongly shaped by acute disturbances (e.g., cyclones, Acanthaster planci outbreaks, and bleaching), thus different coral assemblages may be found at sites with the same environmental conditions. Disturbances also affect foraminiferal assemblages, but they appeared to recover more rapidly than corals. Foraminiferal assemblages are effective bioindicators of turbidity/light regimes and organic enrichment of sediments on coral reefs.

BENTHIC FORAMINIFERAL BIOSTRATIGRAPHY OF MALATYA OLIGO-MIOCENE SUCCESSION (EASTERN TAURIDS, EASTERN TURKEY

Directory of Open Access Journals (Sweden)

Fatma GEDİK

2015-10-01

Full Text Available The benthic foraminiferal biostratigraphy of Oligo-Miocene aged Muratlı and Petekkaya formations which crop out over wide regions around Akçadağ town, west of Malatya pro- vince in Eastern Taurids were revealed in this study. Systematical sampling was carried out in measured stratigraphical sections in four locations in order to perform stratigraphical and paleontological investigations. Benthic foraminifera taken from 182 hard rock samples were defined and three biozones were determined as; SBZ 21-22, belonging to Oligocene (Rupe- lian - Early Chattian, SBZ 23 (Late Chattian and SBZ 25 belonging to Lower Miocene in shallow marine deposits in the region. It was stated that the assemblage of planktic forami- nifer and nannoplankton which stratigraphically detected within Chattian - Burdigalian units in the succession most probably indicated Aquitanian age. Besides; Oligo-Miocene transition in the region was approved with this study based on biostratigraphical locations of benthic foraminiferal taxa.

Eocene sea temperatures for the mid-latitude southwest Pacific from Mg/Ca ratios in planktonic and benthic foraminifera

Science.gov (United States)

Creech, John B.; Baker, Joel A.; Hollis, Christopher J.; Morgans, Hugh E. G.; Smith, Euan G. C.

2010-11-01

We have used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to measure elemental (Mg/Ca, Al/Ca, Mn/Ca, Zn/Ca, Sr/Ca, and Ba/Ca) ratios of 13 species of variably preserved early to middle Eocene planktonic and benthic foraminifera from New Zealand. The foraminifera were obtained from Ashley Mudstone, mid-Waipara River, South Island, which was deposited at bathyal depth ( ca. 1000 m) on the northern margin of the east-facing Canterbury Basin at a paleo-latitude of ca. 55°S. LA-ICP-MS data yield trace element depth profiles through foraminifera test walls that can be used to identify and exclude zones of surficial contamination and infilling material resulting from diagenetic coatings, mineralisation and detrital sediment. Screened Mg/Ca ratios from 5 species of foraminifera are used to calculate sea temperatures from late Early to early Middle Eocene ( ca. 51 to 46.5 Ma), a time interval that spans the termination of the Early Eocene Climatic Optimum (EECO). During this time, sea surface temperatures (SST) varied from 30 to 24 °C, and bottom water temperatures (BWT) from 21 to 14 °C. Comparison of Mg/Ca sea temperatures with published δ 18O and TEX 86 temperature data from the same samples (Hollis et al., 2009) shows close correspondence, indicating that LA-ICP-MS can provide reliable Mg/Ca sea temperatures even where foraminiferal test preservation is variable. Agreement between the three proxies also implies that Mg/Ca-temperature calibrations for modern planktonic and benthic foraminifera can generally be applied to Eocene species, although some species (e.g., V. marshalli) show significant calibration differences. The Mg/Ca ratio of the Eocene ocean is constrained by our data to be 35-50% lower than the modern ocean depending on which TEX 86 - temperature calibration (Kim et al., 2008; Liu et al., 2009) - is used to compare with the Mg/Ca sea temperatures. Sea temperatures derived from δ 18O analysis of foraminifera from Waipara show

Foraminiferal abundance in the modified marine environment of Cola Bay region of Goa

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A.P.; Narayanan, V.

perforate foraminifera are found to be very abundant over all other types in the living populations. In the Cola Bay region of Goa, where the marine environment is affected by the industrial effluents, the foraminiferal distribution shows that @iAmmonia...

Calibrations for benthic foraminiferal Mg/Ca paleothermometry and the carbonate ion hypothesis

NARCIS (Netherlands)

Elderfield, H.; Yu, J.; Anand-Jha, P.; Kiefer, T.; Nyland, B.

2006-01-01

Benthic foraminiferal magnesium/calcium ratios were determined on one hundred and forty core-top samples from the Atlantic Ocean, the Norwegian Sea, the Indian Ocean, the Arabian Sea and the Pacific Ocean, mostly at sites with bottom water temperatures below 5 °C. Mg/Ca ratios are consistently

Planktic foraminiferal photosymbiont bleaching during the Early Eocene Climatic Optimum (Site 1051, northwestern Atlantic)

Science.gov (United States)

Luciani, Valeria; D'Onofrio, Roberta; Dickens, Gerald Roy; Wade, Bridget

2017-04-01

time of the permanent low-latitude morozovellid collapse in abundance, but it affected also the acarininids that proliferated concomitantly. Foraminifera affected by bleaching are expected to reduce their test-size besides abundance, since endosymbiosis is advantageous in foraminiferal longevity and in providing energy to drive calcification. Our record on the species of Morozovella at Site 1051 shows a significant reduction of the maximum test diameter at the initiation of the EECO, thus supporting bleaching. The postulated bleaching episode at the start of the EECO was transitory, as photo-symbiotic activity recovered for Morozovella and Acarinina species within the main EECO phase. However, species of Morozovella never recover their maximum diameter test-size, even after having restored the photo-symbiotic relationship. Decrease in planktic foraminiferal test-size can be related to different types of environmental stressors, in addition to the bleaching. We cannot assign the loss of photo-symbionts to the main cause for morozovellid decline at the EECO onset. Changes in ocean chemistry or interaction with other microplankton groups may have contributed to induce favourable habitat for continued the Acarinina diversification and proliferation during the EECO whereas environmental conditions surpassed a critical threshold for morozovellids. A possible prolonged competition between Morozovella and Acarinina in the mixed-layer for life resources may have resulted in a reduced population for the former.

Organic carbon pattern and foraminiferal assemblage in the sediments of Gulf of Kutch

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A.P.; Ambre, N.V.

. The foraminiferal number (TFN) and the species diversity (TSN) seem to fluctuate with the variation in the sediment pattern. It is highest in the fine clays chiefly with embryonic or meiofaunal in size, thin-walled and hyaline, whereas it is large, thick...

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.

Variability in climate and productivity during the Paleocene-Eocene Thermal Maximum in the western Tethys (Forada section)

Science.gov (United States)

Giusberti, L.; Boscolo Galazzo, F.; Thomas, E.

2016-02-01

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 agglutinated recolonizers. These observations suggest that synergistic stressors, including deepwater 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, and 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

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

Temperature and Productivity Variability Along the Southwestern Portuguese Margin During the Onset of the Mid-Pleistocene Transition

Science.gov (United States)

Salgueiro, E.; Voelker, A. H. L.; Abrantes, F. F. G.; Rodrigues, T.; Sierro, F. J.; Hodell, D. A.; Alberto, A.; Freitas, P. S.

2014-12-01

The Southwest Portuguese Margin sedimentary record is influenced by the Mediterranean Outflow Water (MOW), with a strong thermohaline signature occurring between 500 and 1500m water depth. Variations of MOW intensity during the Late Quaternary (±750ky) are related to changes in the global climate and in the North Atlantic thermohaline circulation. To validate the sedimentary climate records on the Southwestern Portuguese Margin we performed a regional core-top multi-proxy study (Corg, CaCO3, grain size, foraminifera abundances, stable isotopes) to distinguish the MOW effects in recent sediments. The influence of this high velocity bottom current is marked in sediments by a strong increase of the sand content at both, the upper and lower, MOW boundaries. An increase of fine sediments is due to winnowing by the current, resulting in a drastic change in the accumulation rates of any sand-sized biogenic particle. For this reason, some of the traditional productivity proxies used such as Corg, planktonic and benthic foraminifera total abundances, should not be used at sites under the influence of contour currents. However, we demonstrate that the planktonic foraminifera relative abundances can be used with confidence because they are independent of the action of the MOW. Based on the planktonic foraminifera assemblages in two IODP Sites, U1387 recovered from the MOW influenced Faro Drift, and U1385 recovered at 2578m, we reconstruct the sea surface temperature (SST) and export productivity (Pexp) during the beginning of the Mid-Pleistocene Transition, Marine Isotope Stages 36 and 35. At Site U1387: i) foraminifera-derived SST was compared with biomarkers SST and foraminiferal δ18O data; ii) foraminifera-derived Pexp was compared with the Corg; and iii) the influence of the MOW on the sediments was deducted from the weight percent of the sand fraction, indicating contourite layers, and the benthic foraminiferal δ18O and δ13C data.

Synthetical Analysis for Morphology, biological Species, and stable Isotopes (SAMSI) of single-cell planktonic foraminifer

Science.gov (United States)

Ujiie, Y.; Kimoto, K.; Ishimura, T.

2017-12-01

Planktonic foraminifers are widely used in the studies of paleontology and paleoceanography, because the morphology of their calcareous shells is enough highly variable to identify the morphospecies and the chemical composition of the shells reflect ambient seawater condition. Although the morphospecies were believed to represent environments associating with latitudinal temperature range of the world ocean, molecular phylogeographic studies have unveiled the presence of multiple biological species in a single morphospecies and their species-specific distributions. This implicates the actual complexity of planktonic foraminiferal ecology. Conversely, these biological species have a high potential for providing novel ecological and environmental information to us. In order to reassess the morphological and geochemical characters of biological species, the DNA extraction method with the guanidium isothiocyanate buffer was developed to preserve the calcareous shells. The present study carefully tested the physical and chemical damages of the DNA extraction process to the shells, by our novel approaches with geochemical analysis of the shells after non-destructive analysis for morphometrics on a same specimen. First, we checked the changes of the shell densities between pre- and post-DNA extraction by using the micro-focus X-ray CT (MXCT) scanning. Based on the simultaneous measurement of a sample and the standard material, we confirmed no significant changes to the shell densities through the DNA extraction process. As a next step, we compared stable oxygen and carbon isotopes among individuals of three sample sets: (1) no chemical and incubation as control, (2) incubation in the DNA extraction buffer at 65-70°C for 40 minutes as standard way, and (3) incubation in the DNA extraction buffer at 65-70°C for 120 minutes, by using the microscale isotopic analytical system (MICAL3c). Consequently, there were no significant differences among the three sample sets. These

Progress Towards a Global Understanding of Plankton Dynamics: The Global Alliance of CPR Surveys (GACS)

Science.gov (United States)

Batten, S.; Richardson, A.; Melrose, C.; Muxagata, E.; Hosie, G.; Verheye, H.; Hall, J.; Edwards, M.; Koubbi, P.; Abu-Alhaija, R.; Chiba, S.; Wilson, W.; Nagappa, R.; Takahashi, K.

2016-02-01

The Continuous Plankton Recorder (CPR) was first used in 1931 to routinely sample plankton and its continued deployment now sustains the longest-running, and spatially most extensive marine biological sampling programme in the world. Towed behind, for the most part commercial, ships it collects plankton samples from the surface waters that are subsequently analysed to provide taxonomically-resolved abundance data on a broad range of planktonic organisms from the size of coccolithophores to euphausiids. Plankton appear to integrate changes in the physical environment and by underpinning most marine food-webs, pass on this variability to higher trophic levels which have societal value. CPRs are deployed increasingly around the globe in discrete regional surveys that until recently interacted in an informal way. In 2011 the Global Alliance of CPR Surveys (GACS) was launched to bring these surveys together to collaborate more productively and address issues such as: methodological standardization, data integration, capacity building, and data analysis. Early products include a combined global database and regularly-released global marine ecological status reports. There are, of course, limitations to the exploitation of CPR data as well as the current geographic coverage. A current focus of GACS is integration of the data with models to meaningfully extrapolate across time and space. In this way the output could be used to provide more robust synoptic representations of key plankton variables. Recent years have also seen the CPR used as a platform in itself with the inclusion of additional sensors and water samplers that can sample the microplankton. The archive of samples has already been used for some molecular investigations and curation of samples is maintained for future studies. Thus the CPR is a key element of any regional to global ocean observing system of biodiversity.

Bio-magnetochronology for the upper Campanian-Maastrichtian from the Gubbio area, Italy

DEFF Research Database (Denmark)

Gardin, Silvia; Galbrun, Bruno; Thibault, Nicolas Rudolph

2012-01-01

A new bio-chronostratigraphic framework is presented for the upper Campanian - Maastrichtian pelagic sediments of the Gubbio area (Bottaccione and Contessa Highway sections, Italy). New planktonic foraminiferal (FO of P. hantkeninoides), calcareous nannofossil (FO of M. prinsii, base acme of M. m...

Latest Paleocene lithologic and biotic events in neritic deposits of southwestern New Jersey

Science.gov (United States)

Gibson, Thomas G.; Bybell, Laurel M.; Owens, James P.

1993-01-01

In the southwestern New Jersey Coastal Plain, four drill holes contain continuous neritic sedimentation across the Paleocene/Eocene boundary (calcareous nannofossil Zone NP 9/NP 10 boundary). Significant lithologic and biotic changes occur in these strata near the top of the Paleocene. Global warming, increased precipitation, and other oceanographic and climatic events that have been recognized in high-latitude, deep-oceanic deposits of the latest Paleocene also influenced mid-latitude, shallow-marine, and terrestrial environments of the western North Atlantic. The diverse, well-preserved calcareous nannofossil flora that is present throughout the entire New Jersey boundary section accurately places these events within the uppermost part of the upper Paleocene Zone NP 9. Several rapid but gradational changes occur within a 1.1-m interval near the top of Zone NP 9. The changes include (1) a change in lithology from glauconitic quartz sand to clay, (2) a change in clay mineral suites from illite/smectite-dominated to kaolinite-dominated, (3) a change in benthic foraminiferal assemblages to a lower diversity fauna suggestive of low-oxygen environments, (4) a significant increase in planktonic foraminiferal abundance, and (5) an increased species turnover rate in marine calcareous nannofossils. Pollen was sparse in the New Jersey drill holes, but terrestrial sporomorph species in Virginia exhibit increased turnover rates at a correlative level. Foraminiferal assemblages and lithology indicate that relative sea level rose in New Jersey at the same time as these late Paleocene events occurred in late Biochron NP 9. The higher sea levels influenced sediment type and absolute abundance of planktonic foraminifers in the deposits. Above the initial increase of kaolinite in the upper part of Zone NP 9, the kaolinite percentage continues to increase, and the maximum kaolinite value occurs in the uppermost part of Zone NP 9. There are few changes in either the sediments or the

Planktonic Crustacean Culture - Live Planktonic Crustaceans as Live Feed for Finfish and Shrimps in Aquaculture

DEFF Research Database (Denmark)

Jepsen, Per Meyer; Syberg, Kristian; Drillet, Guillaume

2018-01-01

The cultivation of planktonic crustaceans as live feed is of paramount importance for the aquaculture and aquarium industries. The use of live cladocerans as feed for freshwater fish is limited to the aquarium industry, whereas Artemia and copepods are used to feed edible marine fish larvae...... assessments for hazardous chemicals. Cladocerans are widely used for ecotoxicology testing but Artemia and copepods are emerging new model species. In the present chapter, we review the culturing procedures of these important planktonic crustaceans: Artemia, cladocerans and copepods and discuss their use...

Report on the Southern Ocean Continuous Plankton Recorder (SO-CPR Standards Workshop 2016: SCAR SO-CPR Database Expert Group

Directory of Open Access Journals (Sweden)

Kunio T. Takahashi

2017-07-01

Full Text Available The“Southern Ocean Continuous Plankton Recorder (SO-CPR Survey Standards Workshop”was held at the Australian Antarctic Division on 12−16December 2016. The purposes of the workshop were to confirm that consistent and high standards of species identification, methodology, and data quality were being maintained amongst the main analysts in the SO-CPR Survey, and to discuss future training methods, including a SO-CPR manual that will include a counting rule book, and a future road map for the SO-CPR program. During the workshop we discussed a range of topics including: taxonomic resolution issues (particularly for Foraminifera and euphausiid larval identification and staging; laboratory methods (preservation and storage, with emphasis on maintaining correct pH; shipboard techniques; training methods; data handling (metadata, database, data sharing; gap analysis (spatial, temporal, data, quantitative; and future workshops/conferences, including comprehensive training workshops for emerging SO-CPR survey partners (India. We agreed that there should be a larger workshop every two years to ensure that the high standards of the SO-CPR program are maintained.

Plankton of Southern Chilean fjords: trends and linkages

Directory of Open Access Journals (Sweden)

Tarcisio Antezana

1999-12-01

Full Text Available The present paper compiles and reviews past and recent results from Magellan and Fuegian fjords for an overview of the planktonic assemblage there. It first examines linkages to local, adjacent and remote environments. The plankton assemblage presents deviations from the biota of the Magellan biogeographic Province, where the occasional presence of Antarctic species is related to oceanographic phenomena at the Polar Front. Complex bathymetric and hydrographic features within the fjords suggest that the plankton is rather isolated. Adaptations and constraints for population survival, and the role of diel migrators and gregarious zooplankters with regard to bentho-pelagic coupling are discussed. Results on seasonal differences in the plankton of the largest and most isolated basin of the Strait of Magellan are compiled. In spring the plankton was dominated by large diatoms suggesting a short food chain where most of the phytoplankton bloom goes to the bottom, to the meroplankton and to a few dominant holoplankters. In summer, the phytoplankton was dominated by pico- and nanophytoplankton suggesting a more complex food web mediated by a bacterial loop. High abundance of holo- and meroplanktonic larvae coincided with spring blooming conditions.

[Interdependence of plankton spatial distribution and plancton biomass temporal oscillations: mathematical simulation].

Science.gov (United States)

Medvedinskiĭ, A B; Tikhonova, I A; Li, B L; Malchow, H

2003-01-01

The dynamics of aquatic biological communities in a patchy environment is of great interest in respect to interrelations between phenomena at various spatial and time scales. To study the complex plankton dynamics in relation to variations of such a biologically essential parameter as the fish predation rate, we use a simple reaction-diffusion model of trophic interactions between phytoplankton, zooplankton, and fish. We suggest that plankton is distributed between two habitats one of which is fish-free due to hydrological inhomogeneity, while the other is fish-populated. We show that temporal variations in the fish predation rate do not violate the strong correspondence between the character of spatial distribution of plankton and changes of plankton biomass in time: regular temporal oscillations of plankton biomass correspond to large-scale plankton patches, while chaotic oscillations correspond to small-scale plankton patterns. As in the case of the constant fish predation rate, the chaotic plankton dynamics is characterized by coexistence of the chaotic attractor and limit cycle.

Foraminiferal survival after long-term in situ experimentally induced anoxia

Science.gov (United States)

Langlet, D.; Geslin, E.; Baal, C.; Metzger, E.; Lejzerowicz, F.; Riedel, B.; Zuschin, M.; Pawlowski, J.; Stachowitsch, M.; Jorissen, F. J.

2013-11-01

Anoxia was successfully induced in four benthic chambers installed at 24 m depth on the northern Adriatic seafloor from 9 days to 10 months. To accurately determine whether benthic foraminifera can survive experimentally induced prolonged anoxia, the CellTrackerTM Green method was applied and calcareous and agglutinated foraminifera were analyzed. Numerous individuals were found living at all sampling times and at all sampling depths (to 5 cm), supported by a ribosomal RNA analysis that revealed that certain benthic foraminifera were active after 10 months of anoxia. The results show that benthic foraminifera can survive up to 10 months of anoxia with co-occurring hydrogen sulfides. However, foraminiferal standing stocks decrease with sampling time in an irregular manner. A large difference in standing stock between two cores sampled under initial conditions indicates the presence of a large spatial heterogeneity of the foraminiferal faunas. An unexpected increase in standing stocks after one month is tentatively interpreted as a reaction to increased food availability due to the massive mortality of infaunal macrofaunal organisms. After this, standing stocks decrease again in cores sampled after 2 months of anoxia to then attain a minimum in the cores sampled after 10 months. We speculate that the trend of overall decrease of standing stocks is not due to the adverse effects of anoxia and hydrogen sulfides but rather due to a continuous diminution of labile organic matter.

Benthic foraminiferal distribution in surface sediments along continental slope of the southern Okinawa Trough:dependance on water masses and food supply

Institute of Scientific and Technical Information of China (English)

向荣; 李铁刚; 杨作升; 阎军; 曹奇原

2003-01-01

Benthic foraminiferal analysis of 29 samples in surface sediments from the southern Oki-nawa Trough is carried out. The results indicate that benthic foraminiferal abundance decreases rapidlywith increasing water depth. Percentage frequencies of agglutinated foraminifera further confirm themodem shallow carbonate lysocline in the southern Okinawa Trough. From continental shelf edge to thebottom of Okinawa Trough, benthic foraminiferal fauna in the surface sediments can be divided into 5assemblages: (1) Continental shelf break assemblage, dominated by Cibicides pseudoungerianus, corre-sponds to subsurface water mass of the Kuroshio Current; (2) upper continental slope assemblage, domi-nated by Cassidulina carinata, Globocassidulina subglobosa, corresponds to intermediate water mass of the Kuroshio Current; (3) intermediate continental slope assemblage, dominated by Uvigerina hispi-da, corresponds to the Okinawa Trough deep water mass above the carbonate lysocline; (4) lower con-tinental slope- trough bottom assemblage, dominated by Pullenia bulloides, Epistominella exigua andCibicidoides hyalinus, corresponds to deep water mass of the Okinawa Trough; and (5) trough bottomagglutinated assemblage, dominated by Rhabdammina spp., Bathysiphon flavidus, corresponds tostrongly dissolved environment of the trough bottom. The benthic foraminiferal fauna in the southemOkinawa Trough are controlled jointly by water masses and food supply. Water temperature, oxygenconcentration and carbonate dissolution of the water masses are important controlling factors especiallyfor the continental shelf break and trough bottom assemblages. The food supply also plays an importantrole in these benthic foraminiferal assemblages along the westem slope of the Okinawa Trough. Both theabundance and the 5 assemblages of benthic foraminifera correspond well to the organic matter supplyalong the continental slope and a lateral transport of TSM (total suspended matter) and POC (particulateorganic

Foraminiferal studies in nearshore regions of western coast of India and Laccadives Islands: A review

Digital Repository Service at National Institute of Oceanography (India)

Bhalla, S.N.; Khare, N.; Shanmukha, D.H.; Henriques, P.J.

The literature published on foraminiferal investigations carried out till date on nearshore, shallow water regions up to a depth of 50 m, along western coast of India, including Laccadive Archipelago has been reviewed. The aim is to prepare a...

Radionuclides in plankton from the South Pacific Basin

International Nuclear Information System (INIS)

Marsh, K.V.; Buddemeier, R.W.

1984-01-01

An investigation has been initiated of the utility of marine plankton as bioconcentrating samplers of low-level marine radioactivity in the southern hemisphere. A literature review has shown that both freshwater and marine plankton have trace element and radionuclide concentration factors (relative to water) of up to 10 4 . In 1956 and 1958 considerable work was done on the accumulation and distribution of a variety of fission and activation products produced by nuclear tests in the Marshall Islands. Since then, studies, have largely been confined to a few radionuclides, and most of the work in the last twenty years has been done in the northern hemisphere. The authors participated in Operations Deepfreeze 1981 and 1982, collecting a total of 48 plankton samples from the USCGC Glacier on its Antarctic cruises. Battelle Pacific Northwest Laboratories sampled air, water, rain, and fallout. The authors were able to measure concentrations in plankton of the naturally-occurring radionuclides 7 Be, 40 K, and the U and Th series, and they believe that they have detected low levels of 144 Ce and 95 Nb in seven samples ranging as far south as 68 0 . Biological identification of the plankton suggests a possible correlation between radionuclide concentration and the protozoa content of the samples. 7 references, 5 figures, 1 table

Trends in Trace Element Fractionation Between Foraminiferal Species and the Role of Biomineralization

Science.gov (United States)

Reichart, G. J.; Nooijer, L. D.; Geerken, E.; Mezger, E.; van Dijk, I. V.; Daemmer, L. K.

2017-12-01

Reconstructions of past climate and environments are largely based on stable isotopes and trace element concentrations measured on fossil foraminiferal calcite. Their element and isotope composition roughly reflects seawater composition and physical conditions, which in turn, are related to paleoceanographic parameters. More recently, attempts are being made to infer ranges in environmental parameters using the observed differences in the composition within individual tests. Remarkably, inter-species differences in trace element incorporation are well-correlated over a wide range of environmental conditions. This is particularly remarkable knowing that different environmental factors influence incorporation of these elements at various magnitudes. Most likely the complex biomineralization of foraminifera potentially offsets trace elements similarly at all these scales and also between different species. This suggests that at least parts of the mechanisms underlying foraminiferal biomineralization are similar for all species, which in turn provides important clues on the cellular mechanisms operating during calcification. Moreover, the systematics in trace element partitioning between species could potentially provide important clues for unravelling past changes in trace element composition of the ancient ocean.

Large-scale ocean connectivity and planktonic body size

KAUST Repository

Villarino, Ernesto; Watson, James R.; Jö nsson, Bror; Gasol, Josep M.; Salazar, Guillem; Acinas, Silvia G.; Estrada, Marta; Massana, Ramó n; Logares, Ramiro; Giner, Caterina R.; Pernice, Massimo C.; Olivar, M. Pilar; Citores, Leire; Corell, Jon; Rodrí guez-Ezpeleta, Naiara; Acuñ a, José Luis; Molina-Ramí rez, Axayacatl; Gonzá lez-Gordillo, J. Ignacio; Có zar, André s; Martí , Elisa; Cuesta, José A.; Agusti, Susana; Fraile-Nuez, Eugenio; Duarte, Carlos M.; Irigoien, Xabier; Chust, Guillem

2018-01-01

Global patterns of planktonic diversity are mainly determined by the dispersal of propagules with ocean currents. However, the role that abundance and body size play in determining spatial patterns of diversity remains unclear. Here we analyse spatial community structure - β-diversity - for several planktonic and nektonic organisms from prokaryotes to small mesopelagic fishes collected during the Malaspina 2010 Expedition. β-diversity was compared to surface ocean transit times derived from a global circulation model, revealing a significant negative relationship that is stronger than environmental differences. Estimated dispersal scales for different groups show a negative correlation with body size, where less abundant large-bodied communities have significantly shorter dispersal scales and larger species spatial turnover rates than more abundant small-bodied plankton. Our results confirm that the dispersal scale of planktonic and micro-nektonic organisms is determined by local abundance, which scales with body size, ultimately setting global spatial patterns of diversity.

Large-scale ocean connectivity and planktonic body size

KAUST Repository

Villarino, Ernesto

2018-01-04

Global patterns of planktonic diversity are mainly determined by the dispersal of propagules with ocean currents. However, the role that abundance and body size play in determining spatial patterns of diversity remains unclear. Here we analyse spatial community structure - β-diversity - for several planktonic and nektonic organisms from prokaryotes to small mesopelagic fishes collected during the Malaspina 2010 Expedition. β-diversity was compared to surface ocean transit times derived from a global circulation model, revealing a significant negative relationship that is stronger than environmental differences. Estimated dispersal scales for different groups show a negative correlation with body size, where less abundant large-bodied communities have significantly shorter dispersal scales and larger species spatial turnover rates than more abundant small-bodied plankton. Our results confirm that the dispersal scale of planktonic and micro-nektonic organisms is determined by local abundance, which scales with body size, ultimately setting global spatial patterns of diversity.

The Neogene genus Streptochilus (Brönnimann and Resig, 1971) from the Gulf of California

Science.gov (United States)

Miranda Martínez, A.Y.; Carreño, A.L.; McDougall, Kristin

2017-01-01

Four species of the planktonic foraminiferal genus Streptochilus from key Neogene marine localities are documented in relation to the evolution of the Gulf of California: S. globigerus, S. latus, S. macdougallae sp. nov., and S. inglei sp. nov. Planktonic foraminiferal bioevents and strontium isotopes in the Bouse, Tirabuzón, Carmen and Ojo de Buey lithostratigraphic units constrain the local distribution range between 6 and 5.3 Ma for the last three species, whereas S. globigerus appears locally at 5.5 Ma and disappears between 3.79 and 3.46 Ma in the Imperial and Trinidad Formations. The last occurrence of Streptochilus latus, and the first and last occurrences of S. globigerus in the ancient Gulf of California are correlated with bioevents calibrated in the equatorial Pacific; therefore, they can be used as reliable local biostratigraphic markers. The presence of Streptochilus in the ancient Gulf of California seems to correlate with upwelling, in a pattern similar to that observed in the modern oceans.

SEAMAP 2015 Fall Plankton Survey (PC1504, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — During the 2015 Fall Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

SEAMAP 2013 Fall Plankton Survey (PC1305, ME70)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — During the 2013 Fall Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

SEAMAP 2013 Fall Plankton Survey (PC1305, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — During the 2013 Fall Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

SEAMAP Spring 2015 Plankton Survey (GU1501, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — During the 2015 Spring Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

SEAMAP Spring 2016 Plankton Survey (R21601, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — During the 2016 Spring Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

SEAMAP Fall 2014 Plankton Survey (GU1405, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — During the 2014 Fall Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

Impact of salinity on element incorporation in two benthic foraminiferal species with contrasting magnesium contents

Science.gov (United States)

Geerken, Esmee; de Nooijer, Lennart Jan; van Dijk, Inge; Reichart, Gert-Jan

2018-04-01

Accurate reconstructions of seawater salinity could provide valuable constraints for studying past ocean circulation, the hydrological cycle and sea level change. Controlled growth experiments and field studies have shown the potential of foraminiferal Na / Ca as a direct salinity proxy. Incorporation of minor and trace elements in foraminiferal shell carbonate varies, however, greatly between species and hence extrapolating calibrations to other species needs validation by additional (culturing) studies. Salinity is also known to impact other foraminiferal carbonate-based proxies, such as Mg / Ca for temperature and Sr / Ca for sea water carbonate chemistry. Better constraints on the role of salinity on these proxies will therefore improve their reliability. Using a controlled growth experiment spanning a salinity range of 20 units and analysis of element composition on single chambers using laser ablation-Q-ICP-MS, we show here that Na / Ca correlates positively with salinity in two benthic foraminiferal species (Ammonia tepida and Amphistegina lessonii). The Na / Ca values differ between the two species, with an approximately 2-fold higher Na / Ca in A. lessonii than in A. tepida, coinciding with an offset in their Mg content ( ˜ 35 mmol mol-2 versus ˜ 2.5 mmol mol-1 for A. lessonii and A. tepida, respectively). Despite the offset in average Na / Ca values, the slopes of the Na / Ca-salinity regressions are similar between these two species (0.077 versus 0.064 mmol mol-1 change per salinity unit). In addition, Mg / Ca and Sr / Ca are positively correlated with salinity in cultured A. tepida but show no correlation with salinity for A. lessonii. Electron microprobe mapping of incorporated Na and Mg of the cultured specimens shows that within chamber walls of A. lessonii, Na / Ca and Mg / Ca occur in elevated bands in close proximity to the primary organic lining. Between species, Mg banding is relatively similar, even though Mg content is 10 times lower and

Consequences of Stinging Plankton Blooms on Finfish Mariculture in the Mediterranean Sea

Directory of Open Access Journals (Sweden)

Mar Bosch-Belmar

2017-08-01

Full Text Available In recent years, caged finfish mariculture across European seas suffered production losses by severe fish mortality, following episodic outbreaks of invertebrate cnidarian stingers. Due to their stinging cells and injectable venoms, medusozoan jellyfish, or drifting propagules of polyp colonies at high density may impair caged fish health through toxic effects on vulnerable tissues of gills and skin, and related secondary bacterial infections. Gill disorders in European sea bass (Dicentrarchus labrax fish farms along the Spanish Mediterranean coast are commonly reported, but regular monitoring of the frequency of cnidarian outbreaks and their potential impacts on caged fish is still poorly enforced. In this study, two sea bass mariculture farms in Southern Spain (Málaga; Almería were monitored biweekly for zooplankton, phytoplankton and fish gills condition, over 13 or 30 months for the Málaga and Almería facilities, respectively, within the period 2012–2014. Significant, direct correlations were found among low water temperature, recorded fish mortalities, and high abundances of planktonic cnidarians, particularly of the hydrozoan siphonophores Muggiaea atlantica and M. kochii, and the larval stage of Ectopleura larynx, a common member of cage biofouling communities. A significant relationship between cnidarian densities and the quantitative scoring of gill pathology was also observed. In addition, high densities of long-bristled planktonic diatoms (Chaetoceros spp. coincided with a major fish mortality event (April 2012, Almería farm. Standardised monitoring of plankton dynamics and composition may help in promoting response capacities of Mediterranean mariculture managers to fish health challenges (such as stinging plankton blooms by (a improving diagnostic tools and preventative countermeasures and (b supporting the development of science-based spatial planning and sustainable growth of coastal mariculture.

The biomass of the deep-sea benthopelagic plankton

Science.gov (United States)

Wishner, K. F.

1980-04-01

Deep-sea benthopelagic plankton samples were collected with a specially designed opening-closing net system 10 to 100 m above the bottom in five different oceanic regions at depths from 1000 to 4700 m. Benthopelagic plankton biomasses decrease exponentially with depth. At 1000 m the biomass is about 1% that of the surface zooplankton, at 5000 m about 0.1%. Effects of differences in surface primary productivity on deep-sea plankton biomass are much less than the effect of depth and are detectable only in a few comparisons of extreme oceanic regions. The biomass at 10 m above the bottom is greater than that at 100 m above the bottom (in a three-sample comparison), which could be a consequence of an enriched near-bottom environment. The deep-sea plankton biomass in the Red Sea is anomalously low. This may be due to increased decomposition rates in the warm (22°C) deep Red Sea water, which prevent much detritus from reaching the deep sea. A model of organic carbon utilization in the benthic boundary layer (bottom 100 m), incorporating results from deep-sea sediment trap and respiration studies, indicates that the benthopelagic plankton use only a small amount of the organic carbon flux. A large fraction of the flux is unaccounted for by present estimates of benthic and benthopelagic respiration.

An age-calibrated record of upper Campanian – Maastrichtian climate change in the Boreal Realm

DEFF Research Database (Denmark)

Thibault, Nicolas Rudolph; Schovsbo, Niels; Harlou, Rikke

nannofossil chalk is in agreement with planktic biotic events of the latest Cretaceous and matches well with climatic trends of intermediate- and deep-waters from other oceanic basins recorded through benthic foraminiferal d18O (Barrera and Savin, 1999). However, most planktic foraminiferal d18O data do......The latest Cretaceous climate of the Boreal Realm was recorded through high-resolution bulk carbon- and oxygen-stable isotopes and a nannofossil temperature index (NTI) on the Stevns-1 core (Denmark) which recovered 456 m of upper Campanian to basal Danian chalk with ~100% recovery and an excellent...... temperatures (SSTs) in the Boreal Realm. Three warming events punctuate the overall cooling trend of the latest Cretaceous: (1) the late Campanian climatic optimum (73.9–71.6 Ma) is characterized by maximum SSTs of 20°C, (2) the mid-Maastrichtian warming (69.7–68 Ma) is characterized by stable SSTs around 17°C...

Evolution of a Planktonic Foraminifer during Environmental Changes in the Tropical Oceans.

Science.gov (United States)

Ujiié, Yurika; Ishitani, Yoshiyuki

2016-01-01

Ecological adaptation to environmental changes is a strong driver of evolution, enabling speciation of pelagic plankton in the open ocean without the presence of effective physical barriers to gene flow. The tropical ocean environment, which plays an important role in shaping marine biodiversity, has drastically and frequently changed since the Pliocene. Nevertheless, the evolutionary history of tropical pelagic plankton has been poorly understood, as phylogeographic investigations are still in the developing state and paleontological approaches are insufficient to obtain a sequential record from the deep-sea sediments. The planktonic foraminifer Pulleniatina obliquiloculata is widely distributed in the tropical area throughout the world's oceans, and its phylogeography is well established. It is thus one of the best candidates to examine how past environmental changes may have shifted the spatial distribution and affected the diversification of tropical pelagic plankton. Such an examination requires the divergence history of the planktonic foraminifers, yet the gene marker (partial small subunit (SSU) rDNA) previously used for phylogeographic studies was not powerful enough to achieve a high accuracy in estimating the divergence times. The present study focuses on improving the precision of divergence time estimates for the splits between sibling species (genetic types) of planktonic foraminifers by increasing the number of genes as well as the number of nucleotide bases used for molecular clock estimates. We have amplified the entire coding regions of two ribosomal RNA genes (SSU rDNA and large subunit (LSU) rDNA) of three genetic types of P. obliquiloculata and two closely related species for the first time and applied them to the Bayesian relaxed clock method. The comparison of the credible intervals of the four datasets consisting either of sequences of the partial SSU rDNA, the complete SSU rDNA, LSU rDNA, or a combination of both genes (SSU+LSU) clearly

Paleoceanographic Changes during the Past 95000 Years from the Indian Sector of the Southern Ocean

Science.gov (United States)

Manoj, M. C.; Meloth, T.; Mohan, R.

2012-12-01

High-resolution planktic/benthic foraminiferal stable isotope and mean sortable silt records in a sediment core (SK200/22a) from the sub-Antarctic regime of the Indian sector of Southern Ocean depict the variations in surface and deep water hydrography during the past 95,000 years. The δ18O records of shallow- and deep-dwelling planktonic foraminiferal species (Neogloboquadrina pachyderma, Globigerina bulloides and Globorotalia inflata), primarily reflects the changes in upper water column characteristics. The δ18O records revealed the presence of the Antarctic Cold Reversal and the timing of the variability in major surface warming events appears in phase with the Antarctic temperature variations at the millennial time scale. Comparison between the proxies of sea surface conditions like planktonic δ18O and productivity proxies like carbonate and biogenic opal content in the core indicate that millennial scale sea surface warming fluctuated with productivity. The marine isotopic stage (MIS) 1 and MIS2 are characterized by near constant variations in mean sortable silt values, negating any significant changes in the deep water flow during these periods. The MIS 3 - MIS 5 periods were characterized by a general increase in mean sortable silt value, suggesting a strengthening of bottom-current activity that triggered winnowing at these periods. This is supported by the low δ13C records of epibenthic Cibicidoides wuellerstorfi during the glacials and some parts of MIS3 and MIS 5, confirming older nutrient-rich and poorly ventilated southern sourced deep waters at these periods. The termination I is marked by decrease in flow speed and an increase in the C. wuellerstorfi δ13C values. Comparison of mean sortable silt and C. wuellerstorfi δ13C record with the Antarctic ice core records reveal that pulses of reduced bottom water flow of Circumpolar Deep Water/North Atlantic Deep Water are synchronous with the Antarctic warming events. The decreased flow speed during

16S rRNA gene metabarcoding and TEM reveals different ecological strategies within the genus Neogloboquadrina (planktonic foraminifer.

Directory of Open Access Journals (Sweden)

Clare Bird

contained significant numbers of phytoplankton OTUs. We present an alternative view of their trophic interactions and discuss these results within the context of modelling global planktonic foraminiferal abundances in response to high-latitude climate change.

Using flow cytometry for counting natural planktonic bacteria and understanding the structure of planktonic bacterial communities

Directory of Open Access Journals (Sweden)

Josep M. Gasol

2000-06-01

Full Text Available Flow cytometry is rapidly becoming a routine methodology in aquatic microbial ecology. The combination of simple to use bench-top flow cytometers and highly fluorescent nucleic acid stains allows fast and easy determination of microbe abundance in the plankton of lakes and oceans. The different dyes and protocols used to stain and count planktonic bacteria as well as the equipment in use are reviewed, with special attention to some of the problems encountered in daily routine practice such as fixation, staining and absolute counting. One of the main advantages of flow cytometry over epifluorescence microscopy is the ability to obtain cell-specific measurements in large numbers of cells with limited effort. We discuss how this characteristic has been used for differentiating photosynthetic from non-photosynthetic prokaryotes, for measuring bacterial cell size and nucleic acid content, and for estimating the relative activity and physiological state of each cell. We also describe how some of the flow cytometrically obtained data can be used to characterize the role of microbes on carbon cycling in the aquatic environment and we prospect the likely avenues of progress in the study of planktonic prokaryotes through the use of flow cytometry.

Foraminiferal calcification and CO2

Science.gov (United States)

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

2017-12-01

Ongoing burning of fossil fuels increases atmospheric CO2, elevates marine dissolved CO2 and decreases pH and the saturation state with respect to calcium carbonate. Intuitively this should decrease the ability of CaCO3-producing organisms to build their skeletons and shells. Whereas on geological time scales weathering and carbonate deposition removes carbon from the geo-biosphere, on time scales up to thousands of years, carbonate precipitation increases pCO2 because of the associated shift in seawater carbon speciation. Hence reduced calcification provides a potentially important negative feedback on increased pCO2 levels. Here we show that foraminifera form their calcium carbonate by active proton pumping. This elevates the internal pH and acidifies the direct foraminiferal surrounding. This also creates a strong pCO2 gradient and facilitates the uptake of DIC in the form of carbon dioxide. This finding uncouples saturation state from calcification and predicts that the added carbon due to ocean acidification will promote calcification by these organisms. This unknown effect could add substantially to atmospheric pCO2 levels, and might need to be accounted for in future mitigation strategies.

Elevated land runoff after European settlement perturbs persistent foraminiferal assemblages on the Great Barrier Reef.

Science.gov (United States)

Uthicke, S; Patel, F; Ditchburn, R

2012-01-01

Coral reefs are under pressure from a variety of human-induced disturbances, but demonstration of ecosystem changes and identification of stressors are often difficult. We tested whether global change or increased agricultural runoff after European settlement of Northeast Australia (ca. 1860) has affected inshore reefs of the Great Barrier Reef. Eleven sediment cores were retrieved from inner reefs, intermediate reefs, and outer-island reefs, and benthic foraminiferal assemblages were analyzed in dated (14C, 210Pb, 137Cs) core sections (N = 82 samples). Data were grouped into six age bands ( 1500 yr). Principal component analysis and two-factor (Zone and Age) permutational analysis of variance (PERMANOVA) suggested that assemblages from the three zones were significantly different from each other over several millennia, with symbiont-bearing (mixotrophic) species dominating the outer reefs. A significant interaction term indicated that within-zone patterns varied. Assemblages in outer reefs unaffected from increased land runoff were persistent until present times. In both other zones, assemblages were also persistent until 150 yr ago, suggesting that benthic foraminiferal assemblages are naturally highly persistent over long (> 2000 yr) timescales. Assemblages in core sections PERMANOVA. With some exceptions, changes on the inner and intermediate reefs were consistent with a model predicting that increased nutrients and higher turbidity enhance relative abundance of heterotrophic species. Given that assemblages did not change in outer-island reefs (not impacted by runoff) we argue that changes in assemblages due to global change can be rejected as an explanation. Thus, the findings are more consistent with the hypothesis that agricultural runoff since European settlement altered foraminiferal assemblages than with the hypothesis that global forcing caused changes.

1.5 My benthic foraminiferal B/Ca record of carbonate chemistry in the deep Atlantic: Implications for ocean alkalinity and atmospheric CO2

Science.gov (United States)

Rosenthal, Y.; Sosdian, S. M.; Toggweiler, J. R.

2017-12-01

Most hypotheses to explain glacial-interglacial changes in atmospheric CO2 invoke shifts in ocean alkalinity explain roughly half the reduction in glacial CO2 via CaCO3 compensatory mechanism. It follows that changes in CaCO3 burial occur in response to an increase in deep ocean respired carbon content. To date our understanding of this process comes from benthic carbon isotope and %CaCO3 records. However, to understand the nature of the ocean's buffering capacity and its role in modulating pCO2, orbitally resolved reconstructions of the deep ocean carbonate system parameters are necessary. Here we present a 1.5 Myr orbitally resolved deep ocean calcite saturation record (ΔCO32-) derived from benthic foraminiferal B/Ca ratios in the North Atlantic. Glacial B/Ca values decline across the mid-Pleistocene transition (MPT) suggesting increased sequestration of carbon in the deep Atlantic. The magnitude, timing, and structure of deep Atlantic Ocean ΔCO32- and %CaCO3 cycles contrast with the small amplitude, anti-phased swings in IndoPacific ΔCO32- and %CaCO3 during the mid-to-late Pleistocene. Increasing corrosivity of the deep Atlantic causes the locus of CaCO3 burial to shift into the equatorial Pacific where the flux of CaCO3 to the seafloor is high enough to establish and maintain a new "hot spot". We propose that the CO32- in the deep IndoPacific rises in response to the same mechanism that keeps the CO32- in the deep Atlantic low and the atmospheric CO2 low. The increase in interglacial atmospheric pCO2 levels following the Mid-Brunhes event ( 400ka) are associated with increased G/IG ΔCO3 amplitude, expressed by a decrease in the glacial ΔCO32- values. We propose the low persistent ΔCO32- levels at Marine Isotope Stage (MIS) 12 set the stage for the high pCO2 levels at MIS 11 via an increase in whole ocean alkalinity followed by enhanced CaCO3 preservation. Based on this, we suggest that the development of classic (`anticorrelated') CaCO3 patterns was

Sheldon spectrum and the plankton paradox: two sides of the same coin-a trait-based plankton size-spectrum model.

Science.gov (United States)

Cuesta, José A; Delius, Gustav W; Law, Richard

2018-01-01

The Sheldon spectrum describes a remarkable regularity in aquatic ecosystems: the biomass density as a function of logarithmic body mass is approximately constant over many orders of magnitude. While size-spectrum models have explained this phenomenon for assemblages of multicellular organisms, this paper introduces a species-resolved size-spectrum model to explain the phenomenon in unicellular plankton. A Sheldon spectrum spanning the cell-size range of unicellular plankton necessarily consists of a large number of coexisting species covering a wide range of characteristic sizes. The coexistence of many phytoplankton species feeding on a small number of resources is known as the Paradox of the Plankton. Our model resolves the paradox by showing that coexistence is facilitated by the allometric scaling of four physiological rates. Two of the allometries have empirical support, the remaining two emerge from predator-prey interactions exactly when the abundances follow a Sheldon spectrum. Our plankton model is a scale-invariant trait-based size-spectrum model: it describes the abundance of phyto- and zooplankton cells as a function of both size and species trait (the maximal size before cell division). It incorporates growth due to resource consumption and predation on smaller cells, death due to predation, and a flexible cell division process. We give analytic solutions at steady state for both the within-species size distributions and the relative abundances across species.

UV sensitivity of planktonic net community production in ocean surface waters

Science.gov (United States)

Regaudie-de-Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

2014-05-01

The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we test the sensitivity of net community production (NCP) to UVB of planktonic communities in surface waters across contrasting regions of the ocean. We observed here that UVB radiation affects net plankton community production at the ocean surface, imposing a shift in NCP by, on average, 50% relative to the values measured when excluding partly UVB. Our results show that under full solar radiation, the metabolic balance shows the prevalence of net heterotrophic community production. The demonstration of an important effect of UVB radiation on NCP in surface waters presented here is of particular relevance in relation to the increased UVB radiation derived from the erosion of the stratospheric ozone layer. Our results encourage design future research to further our understanding of UVB effects on the metabolic balance of plankton communities.

Epithelial cell detachment by Porphyromonas gingivalis biofilm and planktonic cultures

NARCIS (Netherlands)

Huang, L.; van Loveren, C.; Ling, J.; Wei, X.; Crielaard, W.; Deng, D.M.

2016-01-01

Porphyromonas gingivalis is present as a biofilm at the sites of periodontal infections. The detachment of gingival epithelial cells induced by P. gingivalis biofilms was examined using planktonic cultures as a comparison. Exponentially grown planktonic cultures or 40-h biofilms were co-incubated

UV sensitivity of planktonic net community production in ocean surface waters

OpenAIRE

Regaudie de Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

2014-01-01

The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we tes...

Ecological response of foraminiferal component in the sediments of Kharo Creek, Kachchh (Gujarat), west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Chaturvedi, S.K.; Nigam, R.; Khare, N.

emphasize on the possibility of the detailed foraminiferal study in the creek on seasonal basis as such study will form the base line data to asses the future impact of industrial pollution (if any) as a jetty for offloading cement is being constructed...

Increasing Water Temperature Triggers Dominance of Small Freshwater Plankton.

Science.gov (United States)

Rasconi, Serena; Gall, Andrea; Winter, Katharina; Kainz, Martin J

2015-01-01

Climate change scenarios predict that lake water temperatures will increase up to 4°C and rainfall events will become more intense and frequent by the end of this century. Concurrently, supply of humic substances from terrestrial runoff is expected to increase, resulting in darker watercolor ("brownification") of aquatic ecosystems. Using a multi-seasonal, low trophic state mesocosm experiment, we investigated how higher water temperature and brownification affect plankton community composition, phenology, and functioning. We tested the hypothesis that higher water temperature (+3°C) and brownification will, a) cause plankton community composition to shift toward small sized phytoplankton and cyanobacteria, and, b) extend the length of the growing season entailing higher phytoplankton production later in the season. We demonstrate that the 3°C increase of water temperature favored the growth of heterotrophic bacteria and small sized autotrophic picophytoplankton cells with significantly higher primary production during warmer fall periods. However, 3X darker water (effect of brownification) caused no significant changes in the plankton community composition or functioning relative to control conditions. Our findings reveal that increased temperature change plankton community structure by favoring smaller sized species proliferation (autotrophic phytoplankton and small size cladocerans), and increase primary productivity and community turnover. Finally, results of this multi-seasonal experiment suggest that warming by 3°C in aquatic ecosystems of low trophic state may cause planktonic food web functioning to become more dominated by fast growing, r-trait species (i.e., small sizes and rapid development).

Cold seeps in Monterey Bay, California: Geochemistry of pore waters and relationship to benthic foraminiferal calcite

International Nuclear Information System (INIS)

Gieskes, Joris; Rathburn, Anthony E.; Martin, Jonathan B.; Perez, M. Elena; Mahn, Chris; Bernhard, Joan M.; Day, Shelley

2011-01-01

Highlights: → We describe the geochemistry of pore waters in the Clam Flats area of Monterey Bay. → The geochemical data are compared with the δ 13 C chemistry of benthic foraminifera. → Living foraminifera indicate little effects of pore water low δ 13 C (DIC) in the clam bed. → This phenomenon and its implications are discussed in detail. → Implications with regards to paleo-methane seepage are discussed. - Abstract: An extensive geochemical and biogeochemical examination of CH 4 seeps in the Clam Flats area of Monterey Bay provides insight into the character of relationships between seep geochemistry and benthic foraminiferal geochemistry. The area is characterized by sulfide-rich fluids. Sulfide increases are associated with large increases in alkalinity, as well as small decreases in dissolved Ca and Mg. In addition, only small increases in NH 4 are observed, but values of δ 13 C of dissolved inorganic C are as low as -60 per mille at shallow depths ( 4 , which is transported upward by slow seepage of pore fluids. The geochemistry of the pore fluids should be relevant to the geochemistry of the carbonate tests of living and dead foraminifera. However, a profound disequilibrium of approximately an order of magnitude occurs between the δ 13 C values of stained (cytoplasm-containing) foraminiferal carbonate and the C isotope values of ambient pore water dissolved inorganic C. Reasons are unclear for this isotopic disequilibrium, but have important implications for interpretations of foraminiferal carbonate as a paleoenvironmental proxy. Much fine scale work is needed to fully understand the relationships between the biogeochemistry of benthic foraminifera and the geochemistry of the pore waters where they live.

Foraminiferal-based paleobiogeographic reconstructions in the Carboniferous of Iran and its implications for the Neo-Tethys opening time: a synthesis

International Nuclear Information System (INIS)

Arefifard, S.

2017-01-01

The biogeographic distribution of foraminifers and their belonging to either the southern or northern margins of the Paleo-Tethys are used here for paleogeographic reconstructions of Iran during the Carboniferous. Lower Carboniferous foraminiferal assemblages from northern and central Iran show a cosmopolitan character and affinities to both the southern and northern borders of the Paleo-Tethys. Hence, in the Early Carboniferous Iran occupied an intermediate southern latitude position, forming part of Gondwana. This conclusion is consistent with the Late Ordovician to Early Carboniferous drift history of Iran based on paleomagnetic data. In the Late Carboniferous, the foraminiferal affinities of northern and central Iran with the northern part of Paleo-Tethys suggest that Iran separated from Gondwana and moved northwards to a lower latitude. This separation is also evidenced by the Upper Carboniferous coal-bearing sandstones of the Sardar Formation and sandstones with high degree of chemical weathering, which would indicate warm and humid conditions. Considering the composition of foraminiferal fauna along with the evidence of magmatic activities in northwest Iran, it can be inferred that the commencement of the Neo-Tethys opening and continental break-up in Iran occurred sometime in the Late Carboniferous, which contradicts the previous claims that the separation of Iran from Gondwana occurred in Permian and/or Triassic times.

Foraminiferal-based paleobiogeographic reconstructions in the Carboniferous of Iran and its implications for the Neo-Tethys opening time: a synthesis

Energy Technology Data Exchange (ETDEWEB)

Arefifard, S.

2017-11-01

The biogeographic distribution of foraminifers and their belonging to either the southern or northern margins of the Paleo-Tethys are used here for paleogeographic reconstructions of Iran during the Carboniferous. Lower Carboniferous foraminiferal assemblages from northern and central Iran show a cosmopolitan character and affinities to both the southern and northern borders of the Paleo-Tethys. Hence, in the Early Carboniferous Iran occupied an intermediate southern latitude position, forming part of Gondwana. This conclusion is consistent with the Late Ordovician to Early Carboniferous drift history of Iran based on paleomagnetic data. In the Late Carboniferous, the foraminiferal affinities of northern and central Iran with the northern part of Paleo-Tethys suggest that Iran separated from Gondwana and moved northwards to a lower latitude. This separation is also evidenced by the Upper Carboniferous coal-bearing sandstones of the Sardar Formation and sandstones with high degree of chemical weathering, which would indicate warm and humid conditions. Considering the composition of foraminiferal fauna along with the evidence of magmatic activities in northwest Iran, it can be inferred that the commencement of the Neo-Tethys opening and continental break-up in Iran occurred sometime in the Late Carboniferous, which contradicts the previous claims that the separation of Iran from Gondwana occurred in Permian and/or Triassic times.

Automatic plankton image classification combining multiple view features via multiple kernel learning.

Science.gov (United States)

Zheng, Haiyong; Wang, Ruchen; Yu, Zhibin; Wang, Nan; Gu, Zhaorui; Zheng, Bing

2017-12-28

Plankton, including phytoplankton and zooplankton, are the main source of food for organisms in the ocean and form the base of marine food chain. As the fundamental components of marine ecosystems, plankton is very sensitive to environment changes, and the study of plankton abundance and distribution is crucial, in order to understand environment changes and protect marine ecosystems. This study was carried out to develop an extensive applicable plankton classification system with high accuracy for the increasing number of various imaging devices. Literature shows that most plankton image classification systems were limited to only one specific imaging device and a relatively narrow taxonomic scope. The real practical system for automatic plankton classification is even non-existent and this study is partly to fill this gap. Inspired by the analysis of literature and development of technology, we focused on the requirements of practical application and proposed an automatic system for plankton image classification combining multiple view features via multiple kernel learning (MKL). For one thing, in order to describe the biomorphic characteristics of plankton more completely and comprehensively, we combined general features with robust features, especially by adding features like Inner-Distance Shape Context for morphological representation. For another, we divided all the features into different types from multiple views and feed them to multiple classifiers instead of only one by combining different kernel matrices computed from different types of features optimally via multiple kernel learning. Moreover, we also applied feature selection method to choose the optimal feature subsets from redundant features for satisfying different datasets from different imaging devices. We implemented our proposed classification system on three different datasets across more than 20 categories from phytoplankton to zooplankton. The experimental results validated that our system

Trophic strategies of unicellular plankton

DEFF Research Database (Denmark)

Chakraborty, Subhendu; Nielsen, Lasse Tor; Andersen, Ken Haste

2017-01-01

. To this end, we develop and calibrate a trait-based model for unicellular planktonic organisms characterized by four traits: cell size and investments in phototrophy, nutrient uptake, and phagotrophy. We use the model to predict how optimal trophic strategies depend on cell size under various environmental...... unicellulars are colimited by organic carbon and nutrients, and only large photoautotrophs and smaller mixotrophs are nutrient limited; (2) trophic strategy is bottom-up selected by the environment, while optimal size is top-down selected by predation. The focus on cell size and trophic strategies facilitates......Unicellular plankton employ trophic strategies ranging from pure photoautotrophs over mixotrophy to obligate heterotrophs (phagotrophs), with cell sizes from 10-8 to 1 μg C. A full understanding of how trophic strategy and cell size depend on resource environment and predation is lacking...

AXIALLY ORIENTED SECTIONS OF NUMMULITIDS: A TOOL TO INTERPRET LARGER BENTHIC FORAMINIFERAL DEPOSITS

OpenAIRE

Hohenegger, Johann; Briguglio, Antonino

2012-01-01

The “critical shear velocity” and “settling velocity” of foraminiferal shells are important parameters for determining hydrodynamic conditions during deposition of Nummulites banks. These can be estimated by determining the size, shape, and density of nummulitid shells examined in axial sections cut perpendicular to the bedding plane. Shell size and shape can be determined directly from the shell diameter and thickness, but density must be calculated indirectly from the thin section. Calculat...

Sensitivity of planktonic and biofilm-associated Aeromonas spp. to ionizing radiation

International Nuclear Information System (INIS)

Nagar, Vandan; Bandekar, J.R.

2015-01-01

Genus Aeromonas has emerged as an important human pathogen because it causes a variety of diseases including gastroenteritis and extra-intestinal infections. Aeromonas have the ability to adhere and form biofilms on food surfaces and food contact surfaces. Biofilm formation on foods and food contact surfaces is the major reason for contamination, cross contamination and post-processing contamination of the final food product leading to food spoilage, product rejection, economic losses and food-borne diseases. Biofilms have shown high resistance to heat, desiccation, acidic condition, high salt concentration, antibiotics and other food preservatives. Earlier studies in our laboratory have shown that ionizing radiation effectively inactivates Aeromonas in different food products. However, the relative efficacy of this process against biofilm associated cells versus free-living planktonic cells of Aeromonas is not well documented. Therefore, the dose of gamma radiation required to reduce the population by 90% (D10) was calculated for planktonic and biofilm-associated A. salmonicida Y567 and A. hydrophila A331 cells. Both A. hydrophila A331 and A. salmonicida Y567 expressed significant ability to attach and grow on glass surface following incubation at 30℃ in TSB. Ionizing radiation effectively reduced the populations of both planktonic and biofilm-associated cells for both the strains. Mean cell counts of survivors and surviving fraction of planktonic and biofilm-associated cells decreased with increased irradiation doses. The D10 values of planktonic cells and biofilm cells for A. salmonicida (Y567) were 232.65 Gy and 248.41 Gy, respectively; whereas, the D10 values of planktonic cells and biofilm cells for A. hydrophila (A331) were 249.2 Gy and 240.2 Gy respectively. No significant difference in the D10 values of planktonic and biofilm associated Aeromonas was observed. The influence of the cultured state of the organism, i.e., planktonic versus biofilm associated

Developmental Stages of some Tropical and Subtropical Planktonic Marine Copepods

NARCIS (Netherlands)

Björnberg, Tagea K.S.

1972-01-01

Most planktonic marine copepods have nauplii which differ greatly from the copepodids so that it is difficult to relate them to the adult form. Rearing experiments are usually unsuccessful; only 8% of ca. 800 species of planktonic marine copepods have identified nauplii (see below cited list). To

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.

(15) at 51 m and Miliolid group in station 18 at 25 m depth. The lateral distribution is characterised by a low total species number (TSN) but high total foraminiferal number (TFN) wherein at stations 6, 1, 12 and 26 @iTrochammina inflata@@; @i...

Increasing Water Temperature Triggers Dominance of Small Freshwater Plankton.

Directory of Open Access Journals (Sweden)

Serena Rasconi

Full Text Available Climate change scenarios predict that lake water temperatures will increase up to 4°C and rainfall events will become more intense and frequent by the end of this century. Concurrently, supply of humic substances from terrestrial runoff is expected to increase, resulting in darker watercolor ("brownification" of aquatic ecosystems. Using a multi-seasonal, low trophic state mesocosm experiment, we investigated how higher water temperature and brownification affect plankton community composition, phenology, and functioning. We tested the hypothesis that higher water temperature (+3°C and brownification will, a cause plankton community composition to shift toward small sized phytoplankton and cyanobacteria, and, b extend the length of the growing season entailing higher phytoplankton production later in the season. We demonstrate that the 3°C increase of water temperature favored the growth of heterotrophic bacteria and small sized autotrophic picophytoplankton cells with significantly higher primary production during warmer fall periods. However, 3X darker water (effect of brownification caused no significant changes in the plankton community composition or functioning relative to control conditions. Our findings reveal that increased temperature change plankton community structure by favoring smaller sized species proliferation (autotrophic phytoplankton and small size cladocerans, and increase primary productivity and community turnover. Finally, results of this multi-seasonal experiment suggest that warming by 3°C in aquatic ecosystems of low trophic state may cause planktonic food web functioning to become more dominated by fast growing, r-trait species (i.e., small sizes and rapid development.

Stable-isotope paleoclimatology

International Nuclear Information System (INIS)

Deuser, W.G.

1978-01-01

Seasonal variations of temperature and salinity in the surface waters of large parts of the oceans are well established. Available data on seasonal distributions of planktonic foraminifera show that the abundances of different species groups peak at different times of the year with an apparent succession of abundance peaks through most of the year. This evidence suggests that a measure of seasonal contrast is recorded in the isotope ratios of oxygen, and perhaps carbon, in the tests of different foraminiferal species. The evaluation of this potential paleoclimatologic tool awaits planned experiments with recent foraminifera in well-known settings, but a variety of available data is consistent with the idea that interspecies differences in 18 O content contain a seasonal component.(auth.)

Seasonal variation of plankton communities influenced by environmental factors in an artificial lake

Science.gov (United States)

Li, Xuemei; Yu, Yuhe; Zhang, Tanglin; Feng, Weisong; Ao, Hongyi; Yan, Qingyun

2012-05-01

We evaluated the seasonal variation in plankton community composition in an artificial lake. We conducted microscopic analysis and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified partial 16S rRNA and 18S rRNA genes to characterize the plankton community. The clustering of unweighted pair group method with arithmetic mean (UPGMA) was then used to investigate the similarity of these plankton communities. DGGE fingerprinting revealed that samples collected at the different sites within a season shared high similarity and were generally grouped together. In contrast, we did not observe any seasonal variation based on microscopic analysis. Redundancy analysis (RDA) of the plankton operational taxonomic units (OTUs) in relation to environmental factors revealed that transparency was negatively correlated with the first axis ( R=-0.931), and temperature and total phosphorus (TP) were positively correlated with the first axis ( R=0.736 and R=0.660, respectively). In conclusion, plankton communities in the artificial lake exhibited significant seasonal variation. Transparency, phosphorus and temperature appear to be the major factors driving the differences in plankton composition.

[Research advances in ecological stoichiometry of marine plankton].

Science.gov (United States)

Chen, Lei; Li, Chao-Lun

2014-10-01

Ecological stoichiometry can be simply defined as: The biology of elements from molecules to the biosphere, which spans all levels of the environment and of the life. It's a new idea to build a unified theory and becomes an inevitable trend to develop the ecological science. Marine ecosystems, which contribute to 50% of the biosphere biomass, are the important component of the global biogeochemical cycles. Marine zooplankton plays an important role in the material circulation and energy flow of marine ecosystems and serves as a connecting link between the preceding and the following in a more precise understanding of the key elemental cycles. However, research on ecological stoichiometry of marine plankton is fragmentary and rare. This article summarized the ecological phenomena and mechanisms of limiting elements affecting marine plankton, the response of biochemical substances to nutrition limitation, and the food chain transmission and feedback of nutrition limitation. Meanwhile, we also put forward some perspectives for future research of ecological stoichiometry of plankton in China' s seas.

Planktonic Subsidies to Surf-Zone and Intertidal Communities

Science.gov (United States)

Morgan, Steven G.; Shanks, Alan L.; MacMahan, Jamie H.; Reniers, Ad J. H. M.; Feddersen, Falk

2018-01-01

Plankton are transported onshore, providing subsidies of food and new recruits to surf-zone and intertidal communities. The transport of plankton to the surf zone is influenced by wind, wave, and tidal forcing, and whether they enter the surf zone depends on alongshore variation in surf-zone hydrodynamics caused by the interaction of breaking waves with coastal morphology. Areas with gently sloping shores and wide surf zones typically have orders-of-magnitude-higher concentrations of plankton in the surf zone and dense larval settlement in intertidal communities because of the presence of bathymetric rip currents, which are absent in areas with steep shores and narrow surf zones. These striking differences in subsidies have profound consequences; areas with greater subsidies support more productive surf-zone communities and possibly more productive rocky intertidal communities. Recognition of the importance of spatial subsidies for rocky community dynamics has recently advanced ecological theory, and incorporating surf-zone hydrodynamics would be an especially fruitful line of investigation.

Cold seeps in Monterey Bay, California: Geochemistry of pore waters and relationship to benthic foraminiferal calcite

Energy Technology Data Exchange (ETDEWEB)

Gieskes, Joris, E-mail: jgieskes@ucsd.edu [Scripps Institution of Oceanography, IOD-0208, 9500 Gilman Drive, La Jolla, CA 92093-0208 (United States); Rathburn, Anthony E. [Scripps Institution of Oceanography, IOD-0208, 9500 Gilman Drive, La Jolla, CA 92093-0208 (United States)] [Indiana State University, Department of Earth and Environmental Systems, Terre Haute, IN 47809 (United States); Martin, Jonathan B. [University of Florida, Department of Geological Sciences, Gainesville, FL 32611-2120 (United States); Perez, M. Elena [Indiana State University, Department of Earth and Environmental Systems, Terre Haute, IN 47809 (United States)] [The Natural History Museum, Department of Palaeontology, Cromwell Road, London SW7 5BD (United Kingdom); Mahn, Chris [Scripps Institution of Oceanography, IOD-0208, 9500 Gilman Drive, La Jolla, CA 92093-0208 (United States); Bernhard, Joan M. [Woods Hole Oceanographic Institution, Geology and Geophysics Department, MS52, Woods Hole, MA 02543 (United States); Day, Shelley [University of Florida, Department of Geological Sciences, Gainesville, FL 32611-2120 (United States)

2011-05-15

Highlights: > We describe the geochemistry of pore waters in the Clam Flats area of Monterey Bay. > The geochemical data are compared with the {delta}{sup 13}C chemistry of benthic foraminifera. > Living foraminifera indicate little effects of pore water low {delta}{sup 13}C (DIC) in the clam bed. > This phenomenon and its implications are discussed in detail. > Implications with regards to paleo-methane seepage are discussed. - Abstract: An extensive geochemical and biogeochemical examination of CH{sub 4} seeps in the Clam Flats area of Monterey Bay provides insight into the character of relationships between seep geochemistry and benthic foraminiferal geochemistry. The area is characterized by sulfide-rich fluids. Sulfide increases are associated with large increases in alkalinity, as well as small decreases in dissolved Ca and Mg. In addition, only small increases in NH{sub 4} are observed, but values of {delta}{sup 13}C of dissolved inorganic C are as low as -60 per mille at shallow depths (<3 cm). These observations indicate that all these processes are related to the bacterial oxidation of CH{sub 4}, which is transported upward by slow seepage of pore fluids. The geochemistry of the pore fluids should be relevant to the geochemistry of the carbonate tests of living and dead foraminifera. However, a profound disequilibrium of approximately an order of magnitude occurs between the {delta}{sup 13}C values of stained (cytoplasm-containing) foraminiferal carbonate and the C isotope values of ambient pore water dissolved inorganic C. Reasons are unclear for this isotopic disequilibrium, but have important implications for interpretations of foraminiferal carbonate as a paleoenvironmental proxy. Much fine scale work is needed to fully understand the relationships between the biogeochemistry of benthic foraminifera and the geochemistry of the pore waters where they live.

Ecological partitioning and diversity in tropical planktonic foraminifera

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Seears Heidi A

2012-04-01

Full Text Available Abstract Background Ecological processes are increasingly being viewed as an important mode of diversification in the marine environment, where the high dispersal potential of pelagic organisms, and a lack of absolute barriers to gene flow may limit the occurrence of allopatric speciation through vicariance. Here we focus on the potential role of ecological partitioning in the diversification of a widely distributed group of marine protists, the planktonic foraminifera. Sampling was conducted in the tropical Arabian Sea, during the southwest (summer monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses. Results We uncovered extensive genetic diversity within the Arabian Sea planktonic foraminifera, identifying 13 morphospecies, represented by 20 distinct SSU rRNA genetic types. Several morphospecies/genetic types displayed non-random biogeographical distributions, partitioning between the northern and southern water masses, giving a strong indication of independent ecological adaptations. Conclusions We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed. Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.

Correlating Mediterranean shallow water deposits with global Oligocene–Miocene stratigraphy and oceanic events☆

Science.gov (United States)

Reuter, Markus; Piller, Werner E.; Brandano, Marco; Harzhauser, Mathias

2013-01-01

Shallow-marine sediment records have the strong potential to display sensitive environmental changes in sedimentary geometries and skeletal content. However, the time resolution of most neritic carbonate records is not high enough to be compared with climatic events as recorded in the deep-sea sediment archives. In order to resolve the paleoceanographic and paleoclimatic changes during the Oligocene–Miocene transition in the Mediterranean shallow water carbonate systems with the best possible time resolution, we re-evaluated the Decontra section on the Maiella Platform (central Apennines, Italy), which acts as a reference for the correlation of Oligocene–Miocene shallow water deposits in the Mediterranean region. The 120-m-thick late Oligocene–late Miocene carbonate succession is composed of larger foraminiferal, bryozoan and corallinacean limestones interlayered with distinct planktonic foraminiferal carbonates representing a mostly outer neritic setting. Integrated multi-proxy and facies analyses indicate that CaCO3 and total organic carbon contents as well as gamma-ray display only local to regional processes on the carbonate platform and are not suited for stratigraphic correlation on a wider scale. In contrast, new biostratigraphic data correlate the Decontra stable carbon isotope record to the global deep-sea carbon isotope record. This links relative sea level fluctuations, which are reflected by facies and magnetic susceptibility changes, to third-order eustatic cycles. The new integrated bio-, chemo-, and sequence stratigraphic framework enables a more precise timing of environmental changes within the studied time interval and identifies Decontra as an important locality for correlating not only shallow and deep water sediments of the Mediterranean region but also on a global scale. PMID:25844021

Correlating Mediterranean shallow water deposits with global Oligocene-Miocene stratigraphy and oceanic events.

Science.gov (United States)

Reuter, Markus; Piller, Werner E; Brandano, Marco; Harzhauser, Mathias

2013-12-01

Shallow-marine sediment records have the strong potential to display sensitive environmental changes in sedimentary geometries and skeletal content. However, the time resolution of most neritic carbonate records is not high enough to be compared with climatic events as recorded in the deep-sea sediment archives. In order to resolve the paleoceanographic and paleoclimatic changes during the Oligocene-Miocene transition in the Mediterranean shallow water carbonate systems with the best possible time resolution, we re-evaluated the Decontra section on the Maiella Platform (central Apennines, Italy), which acts as a reference for the correlation of Oligocene-Miocene shallow water deposits in the Mediterranean region. The 120-m-thick late Oligocene-late Miocene carbonate succession is composed of larger foraminiferal, bryozoan and corallinacean limestones interlayered with distinct planktonic foraminiferal carbonates representing a mostly outer neritic setting. Integrated multi-proxy and facies analyses indicate that CaCO 3 and total organic carbon contents as well as gamma-ray display only local to regional processes on the carbonate platform and are not suited for stratigraphic correlation on a wider scale. In contrast, new biostratigraphic data correlate the Decontra stable carbon isotope record to the global deep-sea carbon isotope record. This links relative sea level fluctuations, which are reflected by facies and magnetic susceptibility changes, to third-order eustatic cycles. The new integrated bio-, chemo-, and sequence stratigraphic framework enables a more precise timing of environmental changes within the studied time interval and identifies Decontra as an important locality for correlating not only shallow and deep water sediments of the Mediterranean region but also on a global scale.

Facies and sedimentary environments of the Abu Qada Formation at Gabal El-Gunna, Southeastern Sinai, Egypt

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Tarek Y.M.A. El-Hariri

2012-06-01

Full Text Available The biostratigraphy, microfacies association, mineralogical interferences, depositional environments and geochemical properties of the Abu Qada Formation, which exposed at Gabal El-Gunna Southeastern Sinai, Egypt were delineated. It belongs to the planktonic foraminiferal Whiteinella archaeocretacea Zone of the Late Cenomanian-Early Turonian and consists of calcareous shale and limestone. The calcareous shale facies is characterized by chlorite, smectite and illite with high concentration of P2O5, Zn, Ni, V, and Cr. The carbonate rocks are characterized by foraminiferal wakestone and bioclastic grainstone. These microfacies associations are characterized by barite with high content of Sr. The facies types with faunal contents, geochemical and mineralogical studies suggest a restricted to shelf lagoon open circulation environment.

Benthic foraminifera in the plankton following storms: what does this mean for (palaeo)-ecological interpretations?

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Hart, Malcolm; Molina, Giulia; Smart, Christopher; Widdicombe, Claire

2017-04-01

The Western Channel Observatory was established by the Natural Environment Research Council (NERC), with Plymouth Marine Laboratory managing the two autonomous buoys that are located to the south of Plymouth in the English Channel (Stations L4 and E1): see Smyth et al. (2015). These two locations are now monitored continually and there is regular sampling of the water column and the sea floor at both locations. At Station L4, despite being in waters with a depth of 50 m, benthic foraminifera are regularly found in the surface water plankton samples. Some of these benthic foraminifera contain algal symbionts, indicating that they may be living at the time of capture. If benthic foraminifera can be entrained in the water column, while still living, then this provides a mechanism for 'migration' that is much more rapid and efficient than the rate at which protists could migrate within, or on, the sediment surface. Recolonization by foraminifera, following disturbance, could well be facilitated by this mechanism which has only rarely been reported in the literature (e.g., Murray, 1965). It is clearly limited to depths impacted by fair weather ( 30 m) or storm wave base (80 - 100 m). Data gathered during winter 2015-2016 certainly indicate that, following storm events, the larger the number of benthic foraminifera in the plankton tows and the greater their overall size. Some of the individuals being observed appear to contain sediment, indicating that they have been picked up from the sediment surface and, despite their greater weight, have still been transported into the plankton. Using data from the nearby sea area, off-shore and within Plymouth Sound, we are trying to ascertain if the recorded assemblage is from the L4 area, or whether they have been transported out from shallower-water environments, possibly assisted by increased run-off caused by heavy rainfall (associated with the storms). Clearly, re-distribution of foraminifera in the environment might make

The structure and evolution of plankton communities

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Longhurst, Alan R.

New understanding of the circulation of ancient oceans is not yet matched by progress in our understanding of their pelagic ecology, though it was the planktonic ecosystems that generated our offshore oil and gas reserves. Can we assume that present-day models of ecosystem function are also valid for ancient seas? This question is addressed by a study of over 4000 plankton samples to derive a comprehensive, global description of zooplankton community structure in modern oceans: this shows that copepods form only 50% of the biomass of all plankton, ranging from 70% in polar to 35% in tropical seas. Comparable figures are derived from 14 other taxonomic categories of zooplankton. For trophic groupings, the data indicate globally: geletinous predators - 14%; gelatinous herbivores - 4%; raptorial predators - 33%; macrofiltering herbivores - 20%; macrofiltering omnivores - 25%; and detritivores - 3%. A simple, idealized model for the modern pelagic ecosystem is derived from these percentages which indicates that metazooplankton are not the most important consumers of pico- and nano-plankton production which itself probably constitutes 90% of primary production in warm oceans. This model is then compared with candidate life-forms available in Palaeozoic and Mesozoic oceans to determine to what extent it is also valid for ancient ecosystems: it is concluded that it is probably unnecessary to postulate models fundamentally differing from it in order to accommodate the life-forms, both protozoic and metazoic, known to have populated ancient seas. Remarkably few life-forms have existed which cannot be paralleled in the modern ocean, which contains remarkably few life-forms which cannot be paralleled in the Palaeozoic ocean. As a first assumption, then, it is reasonable to assume that energy pathways were similar in ancient oceans to those we study today.

Progressive changes in the Western English Channel foster a reorganization in the plankton food web

DEFF Research Database (Denmark)

Reygondeau, Gabriel; Molinero, J.C.; Coombs, S.

2015-01-01

. (2013) drive a profound restructuration of the plankton community modifying the phenology and the dominance of key planktonic groups including fish larvae. Consequently, the slow but deep modifications detected in the plankton community highlight a climate driven ecosystem shift in the Western English...

Ecological-network models link diversity, structure and function in the plankton food-web

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D'Alelio, Domenico; Libralato, Simone; Wyatt, Timothy; Ribera D'Alcalà, Maurizio

2016-02-01

A planktonic food-web model including sixty-three functional nodes (representing auto- mixo- and heterotrophs) was developed to integrate most trophic diversity present in the plankton. The model was implemented in two variants - which we named ‘green’ and ‘blue’ - characterized by opposite amounts of phytoplankton biomass and representing, respectively, bloom and non-bloom states of the system. Taxonomically disaggregated food-webs described herein allowed to shed light on how components of the plankton community changed their trophic behavior in the two different conditions, and modified the overall functioning of the plankton food web. The green and blue food-webs showed distinct organizations in terms of trophic roles of the nodes and carbon fluxes between them. Such re-organization stemmed from switches in selective grazing by both metazoan and protozoan consumers. Switches in food-web structure resulted in relatively small differences in the efficiency of material transfer towards higher trophic levels. For instance, from green to blue states, a seven-fold decrease in phytoplankton biomass translated into only a two-fold decrease in potential planktivorous fish biomass. By linking diversity, structure and function in the plankton food-web, we discuss the role of internal mechanisms, relying on species-specific functionalities, in driving the ‘adaptive’ responses of plankton communities to perturbations.

[Effect of Pseudomonas aeruginosa exometabolites on planktonic and biofilm cultures of Escherichia coli].

Science.gov (United States)

Kuznetsova, M V; Karpunina, T I; Maslennikova, I L; Nesterova, L Iu; Demakov, V A

2012-01-01

Study the effect of P. aeruginosa exometabolites on planktonic and biofilm cultures of bioluminescent E. coli strain. E. coli K12 TG1 (pF1 lux+ Ap(r)) recombinant bioluminescent strain, P. aeruginosa ATCC 27853 reference strain and 2 nosocomial isolates were used. Pyocyanin and pyoverdin content in supernatant of P. aeruginosa over-night cultures was evaluated according to E. Deziel et al. (2001). Planktonic and biofilm cultures of E. coli were obtained in 96-well plates (LB, statically, 37 degrees C), optical density of plankton, film biomass (OD600, OD580) and bioluminescence in plankton and biofilm were evaluated in microplate reader Infiniti M200 (Tecan, Austria). P. aeruginosa exometabolites increased the duration of lag-phase in E. coli, and short term exposition inhibited luminescence of planktonic cells. These effects are determined by bactericidal action ofpyocyanin and pyoverdin. Supernatants ofover-night cultures of P. aeruginosa inhibit formation of biofilm and disrupt the formed biofilm of E. coli. Effect of pyocyanin and pyoverdin on these processes is not established, other factors may have higher significance. Bioluminescence of E. coli K12 TGI that reflects the energetic status of the cell allows to evaluate and prognose the character of coexistence of P. aeruginosa in combined with E. coli planktonic and biofilm culture.

Stable isotopic fractionation, climate change and episodic stagnation in the eastern Mediterranean during the late Quaternary

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Vergnaud-Grazzini, C [Laboratoire de Geologie Dynamique, Paris (France); Ryan, W B.F. [Columbia Univ., Palisades, NY (USA). Lamont-Doherty Geological Observatory; Cita, M B [Milan Univ. (Italy)

1977-11-01

Fluctuations in the delta/sup 18/O composition of planktonic foraminifers in eastern Mediterranean piston cores indicate cycles with amplitudes much greater than those which can be attributed alone to global ice-volume changes. Isotopic values become markedly negative within lithostratigraphic levels characterized by the apparition of organic-rich sapropels. These owe their origin to the development of euxinic bottom water during episodes of basin-wide stagnation. The depletion of delta/sup 18/O in many of the sapropels is accompanied by the occurrence of poorly diversified planktonic faunas, and both phenomena are attributed to a strong dilution of the local eastern Mediterranean surface water mass by a combination of glacial run off from large continental ice sheets and by an important increase of regional precipitation synchronous with the transition from pleniglacial to kataglacial climate. Although sapropel accumulation occurs generally during intervals of warming of the Mediterranean region as determined from a quantitative evaluation of planktonic foraminiferal assemblages, the pre-125,000 years, local warming of eastern Mediterranean surface water lagged the acme of glacial melting by up to 15,000 years. Climatic and isotopic cycles are correlative within the eastern Mediterranean for lateral distances in excess of 1000 km and, except for amplitude and phase, they are in most aspects remarkably similar to those recorded in the equatorial Pacific and Caribbean.

Covariance among North Sea nutrient and climate drivers: consequences for plankton dynamics.

NARCIS (Netherlands)

McQuatters-Gollop, A.; Vermaat, J.E.

2011-01-01

Regime shift and principal component analysis of a spatially disaggregated database capturing time-series of climatic, nutrient and plankton variables in the North Sea revealed considerable covariance between groups of ecosystem indicators. Plankton and climate time-series span the period 1958-2003,

Dosimetry of natural and man-made alpha emitters in plankton

International Nuclear Information System (INIS)

Paschoa, A.S.; Baptista, G.B.; Wrenn, M.E.; Eisenbrid, M.

1980-11-01

Comparison between the natural and man-made alpha radiation dose rates to plankton can be important for predicting the potential long-term effects on aquatic biota resulting from the routine or accidental radioactive releases from the nuclear fuel cycle. A contribution is made here towards the goal of comparing natural with man-made alpha radiation dose rates to plankton using the same method of calculation in both cases. (Author) [pt

Daytime pelagic schooling behaviour and relationships with plankton patch distribution in the Sicily Strait (Mediterranean Sea

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B. Patti

2011-06-01

Full Text Available In this study, hydroacoustic data collected with a scientific echosounder working at two frequencies (38 and 120 kHz over the continental shelf off the southern Sicilian coast were used in order to investigate the relationship between fish schools and plankton patches. Specifically, image analysis algorithms were applied to raw echograms in order to detect and characterise pelagic fish schools and plankton aggregations, considered as a proxy of food availability. The relationship was first investigated using estimated total plankton biomass over the whole water column and, second, by dividing the study area into three sub-regions and further distinguishing plankton patches between the surface and the bottom. In the relatively lower plankton abundance areas of Zone 1 (northern sector of the study area, results showed an inverse relationship between the biomass (and density of fish schools and the biomass of co-occurring plankton patches located close to the bottom. Instead, over the Sicilian-Maltese shelf (Zone 3, characterised by higher plankton abundances, a direct relationship was found when using plankton data from the whole water column. The observed difference between Zones 1 and 3 is probably due to diverse dominant fish species in the two sub-regions.

Evaluation of parameters of a plankton community's biological rhythms under the natural environment of the Black Sea using the Fourier transform method.

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Mel'nikova, Ye B

2017-05-01

Night-time changes in bioluminescence intensity in the coastal area of the Black Sea were recorded. It was noted that the biomass of luminous organisms is closely correlated with the biomass of plankton and other pelagic organisms, including commercial pelagic fish. The parameters of plankton communities' basic biological rhythms were determined using the discrete Fourier transform method. These rhythms were manifest as spatial and temporal changes in the bioluminescence intensity. It was shown that changes in the bioluminescence intensity over a 14.0-h period were due to the duration of the light/dark cycles. By contrast, changes in bioluminescence intensity with periods of 4.7 and 2.8 h were due to the endogenous rhythms of the plankton community (feeding and cell division). An original method for evaluating of errors in the calculated periods of the biological rhythms was proposed. A strong correlation (r = 0.906) was observed between the measured and calculated values for the bioluminescence intensity, which provided support for the assumptions made. Copyright © 2016 John Wiley & Sons, Ltd.

Modelling emergent trophic strategies in plankton

DEFF Research Database (Denmark)

Andersen, Ken Haste; Aksnes, Dag L.; Berge, Terje

2015-01-01

Plankton are typically divided into phytoplankton and zooplankton in marine ecosystem models. Yet, most protists in the photic zone engage in some degree of phagotrophy, and it has been suggested that trophic strategy is really a continuum between pure phototrophs (phytoplankton) and pure...

Pleistocene Thermocline Reconstruction and Oxygen Minimum Zone Evolution in the Maldives

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Yu, S. M.; Wright, J.

2017-12-01

Drift deposits of the southern flank the Kardiva Channel in the eastern Inner Sea of the Maldives provide a complete record of Pleistocene water column changes in conjunction with monsoon cyclicity and fluctuations in the current system. We sampled IODP Site 359-U1467 to reconstruct water column using foraminiferal stable isotope records. This unlithified lithostratigraphic unit is rich in well-preserved microfossils and has an average sedimentation rate of 3.4 cm/yr. Marine Isotope Stages 1-6 were identified and show higher sedimentation rates during the interglacial sections approaching 6 cm/kyr. We present the δ13C and δ18O record of planktonic and benthic foraminiferal species taken at intervals of 3 cm. Globigerinoides ruber was used to constrain surface conditions. The thermocline dwelling species, Globorotalia menardii, was chosen to monitor fluctuations in the thermocline compared to the mixed layer. Lastly, the δ13C of the benthic species, Cibicidoides subhaidingerii and Planulina renzi, reveal changes to the bottom water ventilation and expansion of oxygen minimum zones over time. All three taxa recorded similar changes in δ18O over the glacial/interglacial cycles which is remarkable given the large sea level change ( 120 m) and the relatively shallow water depth ( 450 m). There is a small increase in the δ13C gradient during the glacial intervals which might reflect less ventilated bottom waters in the Inner Sea. This multispecies approach allows us to better constrain the thermocline hydrography and suggests that changes in the OMZ thickness are driven by the intensification of the monsoon cycles while painting a more cohesive picture to the changes in the water column structure.

Simulated Sampling of Estuary Plankton

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Fortner, Rosanne W.; Jenkins, Deborah Bainer

2009-01-01

To find out about the microscopic life in the valuable estuary environment, it is usually necessary to be near the water. This dry lab offers an alternative, using authentic data and a simulation of plankton sampling. From the types of organisms found in the sample, middle school students can infer relationships in the biological and physical…

Calcareous nannoplankton and benthic foraminiferal assemblages from the Nazare Canyon (Portuguese continental margin): Preliminary results

International Nuclear Information System (INIS)

Guerreiro, C; Oliveira, A; Rodrigues, A; Rosa, F; Cachao, M; Fatela, F

2009-01-01

Submarine canyons are assumed to play an important role in oceanic/neritic circulation, marine productivity and sedimentary processes, acting as preferential conduits between the littoral and deep oceanic domain. Here we present first results of a comparative micropalaeontological study on calcareous nannoplankton and benthic foraminifera from surface sediments from the surroundings of the upper Nazare Canyon (Portuguese continental margin) and from the shelf north of the canyon. Regardless of the difficulty to distinguish taphonomical from (palaeo)ecological effects in such a complex and still poorly known marine system, the first results suggest that the canyon's hydro-sedimentary dynamic regime act as a prolongation of the shore/inner shelf hydrodynamic conditions towards west, preventing deposition and/or preservation of the smaller and fragile species of calcareous nannoplankton (e.g. E. huxleyi and G. ericsonii) and enhancing the record of the larger and more opportunistic ones (e.g. G. oceanica); and disturbing benthic foraminiferal productivity and/or diversity, or their preservation in the fossil record. Both calcareous nannoplankton and benthic foraminifera are more abundant off the canyon's domain, suggesting that its highly energetic thalweg conditions are probably filtering the fossil record in the sediment. Still, preliminary results suggest that the occurrence of persistent physical phenomena related with the canyon's morphology and proximity to the coast (e.g. solitary internal waves) may be locally promoting favourable conditions for calcareous nannoplankton, as shown by high values of nannoliths, chlorophyll a and 19' hexanoyloxyfucoxantine (unpublished data) north of the canyon's head. It is our goal to test this hypothesis in the near future by (a) studying multicore and surficial sediments from more recent surveys, and (b) calibrating the sediment results with water column data presently in process at the Institute of Oceanography (IO).

Calcareous nannoplankton and benthic foraminiferal assemblages from the Nazare Canyon (Portuguese continental margin): Preliminary results

Energy Technology Data Exchange (ETDEWEB)

Guerreiro, C; Oliveira, A; Rodrigues, A [Division of Marine Geology, Portuguese Hydrographic Institute (IH), Rua das Trinas 49, 1249-093 Lisboa (Portugal); Rosa, F [CIACOMAR, Algarve University, Av. 16 de Julho s/n 8700-311 Olhao (Portugal); Cachao, M; Fatela, F [Geology Center and Geology Department, FCUL, Bloco C6, 3o Piso, sala 6.3.57 Campo Grande 1749-016 Lisboa (Portugal)], E-mail: catarina.guerreiro@hidrografico.pt

2009-01-01

Submarine canyons are assumed to play an important role in oceanic/neritic circulation, marine productivity and sedimentary processes, acting as preferential conduits between the littoral and deep oceanic domain. Here we present first results of a comparative micropalaeontological study on calcareous nannoplankton and benthic foraminifera from surface sediments from the surroundings of the upper Nazare Canyon (Portuguese continental margin) and from the shelf north of the canyon. Regardless of the difficulty to distinguish taphonomical from (palaeo)ecological effects in such a complex and still poorly known marine system, the first results suggest that the canyon's hydro-sedimentary dynamic regime act as a prolongation of the shore/inner shelf hydrodynamic conditions towards west, preventing deposition and/or preservation of the smaller and fragile species of calcareous nannoplankton (e.g. E. huxleyi and G. ericsonii) and enhancing the record of the larger and more opportunistic ones (e.g. G. oceanica); and disturbing benthic foraminiferal productivity and/or diversity, or their preservation in the fossil record. Both calcareous nannoplankton and benthic foraminifera are more abundant off the canyon's domain, suggesting that its highly energetic thalweg conditions are probably filtering the fossil record in the sediment. Still, preliminary results suggest that the occurrence of persistent physical phenomena related with the canyon's morphology and proximity to the coast (e.g. solitary internal waves) may be locally promoting favourable conditions for calcareous nannoplankton, as shown by high values of nannoliths, chlorophyll a and 19' hexanoyloxyfucoxantine (unpublished data) north of the canyon's head. It is our goal to test this hypothesis in the near future by (a) studying multicore and surficial sediments from more recent surveys, and (b) calibrating the sediment results with water column data presently in process at the Institute of

Identification of major planktonic sulfur oxidizers in stratified freshwater lake.

Directory of Open Access Journals (Sweden)

Hisaya Kojima

Full Text Available Planktonic sulfur oxidizers are important constituents of ecosystems in stratified water bodies, and contribute to sulfide detoxification. In contrast to marine environments, taxonomic identities of major planktonic sulfur oxidizers in freshwater lakes still remain largely unknown. Bacterioplankton community structure was analyzed in a stratified freshwater lake, Lake Mizugaki in Japan. In the clone libraries of 16S rRNA gene, clones very closely related to a sulfur oxidizer isolated from this lake, Sulfuritalea hydrogenivorans, were detected in deep anoxic water, and occupied up to 12.5% in each library of different water depth. Assemblages of planktonic sulfur oxidizers were specifically analyzed by constructing clone libraries of genes involved in sulfur oxidation, aprA, dsrA, soxB and sqr. In the libraries, clones related to betaproteobacteria were detected with high frequencies, including the close relatives of Sulfuritalea hydrogenivorans.

Effects of the global changes on the aquatic ecosystems in West Europe - role of the plankton communities

International Nuclear Information System (INIS)

Souissi, S.

2007-01-01

Examination of long-term records of aquatic ecosystems has provided useful information to find out their major driving forces. Understanding the impact of climate change on these ecosystems, the management of their resources and the extrapolation between sites are the main scopes of actual and emerging studies. Such goals can be achieved by inter-site and inter-ecosystem comparisons. This approach was undertaken during our project which has the originality to tackle with marine and freshwater ecosystems. It allowed us to compile and validate several multi-decadal time series of planktonic and other physical driving forces at local and regional scales. Then, the same methodology based on the analysis of the variability of climate indices and biological data across several spatial scales was used. The different ecosystems analyzed here showed clear response to the North Atlantic climate variability. Although the local differences abrupt changes in community composition occurred in all ecosystems in the middle of the years 80. During this period there was also a major shift in climatic conditions during winter and early spring, suggesting an impact of climatic factors. Phenological changes were also observed in plankton communities in all sites. The consequences of the modifications of plankton dynamics on higher trophic levels were also showed. Fluctuations in plankton have resulted in long-term changes in cod recruitment in the North Sea (bottom-up control). On the other hand, both climate change and the improvement of trophic status in Geneva Lake favored the outbreak of whitefish during the years 90. Lower larval mortality and better recruitment are supposed to be linked to faster growth associated with warmer temperatures and better food conditions induced by better temporal overlap between larvae hatching and zooplankton development. (author)

Activities of Fluconazole, Caspofungin, Anidulafungin, and Amphotericin B on Planktonic and Biofilm Candida Species Determined by Microcalorimetry

Science.gov (United States)

Maiolo, Elena Maryka; Furustrand Tafin, Ulrika; Borens, Olivier

2014-01-01

We investigated the activities of fluconazole, caspofungin, anidulafungin, and amphotericin B against Candida species in planktonic form and biofilms using a highly sensitive assay measuring growth-related heat production (microcalorimetry). C. albicans, C. glabrata, C. krusei, and C. parapsilosis were tested, and MICs were determined by the broth microdilution method. The antifungal activities were determined by isothermal microcalorimetry at 37°C in RPMI 1640. For planktonic Candida, heat flow was measured in the presence of antifungal dilutions for 24 h. Candida biofilm was formed on porous glass beads for 24 h and exposed to serial dilutions of antifungals for 24 h, and heat flow was measured for 48 h. The minimum heat inhibitory concentration (MHIC) was defined as the lowest antifungal concentration reducing the heat flow peak by ≥50% (≥90% for amphotericin B) at 24 h for planktonic Candida and at 48 h for Candida biofilms (measured also at 24 h). Fluconazole (planktonic MHICs, 0.25 to >512 μg/ml) and amphotericin B (planktonic MHICs, 0.25 to 1 μg/ml) showed higher MHICs than anidulafungin (planktonic MHICs, 0.015 to 0.5 μg/ml) and caspofungin (planktonic MHICs, 0.125 to 0.5 μg/ml). Against Candida species in biofilms, fluconazole's activity was reduced by >1,000-fold compared to its activity against the planktonic counterparts, whereas echinocandins and amphotericin B mainly preserved their activities. Fluconazole induced growth of planktonic C. krusei at sub-MICs. At high concentrations of caspofungin (>4 μg/ml), paradoxical growth of planktonic C. albicans and C. glabrata was observed. Microcalorimetry enabled real-time evaluation of antifungal activities against planktonic and biofilm Candida organisms. It can be used in the future to evaluate new antifungals and antifungal combinations and to study resistant strains. PMID:24566186

Live and dead benthic foraminiferal faunas from Whittard Canyon (NE Atlantic): Focus on taphonomic processes and paleo-environmental applications

NARCIS (Netherlands)

Duros, P.; Fontanier, C.; de Stigter, H.C.; Cesbron, F.; Metzger, E.; Jorissen, F.J.

2012-01-01

Dead benthic foraminiferal assemblages were studied in the > 150 mu m fraction of 4-5 cm deep sediment levels at 18 stations in the Whittard Canyon area in June 2007. This sediment layer is composed of fairly recent sediment (<312 years). The stations were located along 4 bathymetric transects

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.

Thirty species of living planktonic foraminifera have been studied from 97 plankton tows collected from the eastern Arabian Sea with an accent on their ecological and distributional aspects. Species density is higher with less dominance in the deep...

Plankton as an indicator of the temporal variation of the Chernobyl fallout

International Nuclear Information System (INIS)

Ravera, O.; Giannoni, L.

1995-01-01

Here we describe the pattern of radionuclide activities (iodine-131; cesium-134; cesium-137; ruthenium-106) in net-plankton and water samples collected from two lakes in Northern Italy (Lake Monate and Lake Comabbio) during and after the presence in the area of the radioactive cloud from the Chernobyl accident: from 30 April to 3 September 1986. The results show that, because of its short lifespan, plankton is a good indicator of daily variations of environmental contamination. The contamination level of plankton depends on various factors, such as the speciation and biological role of the radionuclide, the community structure and chemical characteristics of the water

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.

), indicated by black arrows are remarkably present for all three trap locations. (Modified after Curry et l.t 1992). 2002; Eguchi, Ujiie, Kawahata and Taira 2003), (ii) all the traps can not stop functioning simultaneously and that for the same time... estimates of the life spans of planktonic foraminifera based on extrapolation of lab culture observations. According to Be et al (1981), an inverse relationship exists between feeding frequency and survival time, and that planktonic foraminifers under...

Over 100 years of environmental change recorded by foraminifers and sediments in Mobile Bay, Alabama, Gulf of Mexico, USA

Science.gov (United States)

Osterman, Lisa E.; Smith, Christopher G.

2012-12-01

The marine microfauna of Mobile Bay has been profoundly influenced by the development and expansion of the primary shipping channel over the last ˜100 years. Foraminifers and sediments from seven box cores with excess lead-210 chronology document that channel dredging and spoil disposal have altered circulation, reduced estuarine mixing, changed sedimentation patterns, and caused a faunal turnover within the bay. Beginning in the late 1800s, changes in estuarine mixing allowed for greater low-pH freshwater influence in the bay, and ultimately began environmental changes that resulted in the loss of calcareous foraminifers. By the early 1900s, box cores throughout Mobile Bay record a ˜100-year trend of increasing calcareous test dissolution that continues to the present. Since the completion of the current shipping channel in the 1950s, restricted tidal flushing and increased terrestrial organic matter, documented by carbon-to-nitrogen ratios, stimulated an increase in agglutinated foraminiferal densities. However, in deeper areas of the bay, hypoxic water has negatively impacted the marine microfauna. Comparisons of the present-day foraminiferal assemblage with foraminifers collected in the early 1970s indicate that the continued biologic loss of calcareous foraminifers in the bay has allowed the introduction of a new agglutinated foraminiferal species into the bay.

Western Indian Ocean circulation and climate variability on different time scales. A study based on stable oxygen and carbon isotopes, benthic foraminiferal assemblages and Mg/Ca paleothermometry

Energy Technology Data Exchange (ETDEWEB)

Romahn, Sarah

2014-08-19

In order to understand the Earth's climate evolution it is crucial to evaluate the role of low-latitude oceans in the global climate system, as they are connected to both hemispheres via atmospheric and oceanic circulation and thus hold the potential to disentangle the asynchronicity of short-term Pleistocene climate variability. However, the potential of low latitude oceans to respond to and force large-scale changes of the climate system is still debated. The aim of this thesis is to examine and to understand the causal relationship of both atmospheric and oceanic changes in the tropical western Indian Ocean on centennial-, millennial and glacial-interglacial timescales. For this purpose I investigated stable oxygen and carbon isotope compositions of both planktic and benthic foraminiferal tests, Mg/Ca ratios of planktic foraminiferal tests as well as benthic foraminiferal assemblages and sedimentary geochemical parameters on two sediment cores (GeoB12615-4, 446 m and GeoB12616-4, 1449 m) from the continental slope off Tanzania, East Africa.

Western Indian Ocean circulation and climate variability on different time scales. A study based on stable oxygen and carbon isotopes, benthic foraminiferal assemblages and Mg/Ca paleothermometry

International Nuclear Information System (INIS)

Romahn, Sarah

2014-01-01

In order to understand the Earth's climate evolution it is crucial to evaluate the role of low-latitude oceans in the global climate system, as they are connected to both hemispheres via atmospheric and oceanic circulation and thus hold the potential to disentangle the asynchronicity of short-term Pleistocene climate variability. However, the potential of low latitude oceans to respond to and force large-scale changes of the climate system is still debated. The aim of this thesis is to examine and to understand the causal relationship of both atmospheric and oceanic changes in the tropical western Indian Ocean on centennial-, millennial and glacial-interglacial timescales. For this purpose I investigated stable oxygen and carbon isotope compositions of both planktic and benthic foraminiferal tests, Mg/Ca ratios of planktic foraminiferal tests as well as benthic foraminiferal assemblages and sedimentary geochemical parameters on two sediment cores (GeoB12615-4, 446 m and GeoB12616-4, 1449 m) from the continental slope off Tanzania, East Africa.

On the Recurrence of Enigmatic Nannoplankton Blooms in the Subtropical South Atlantic during the Early Oligocene

Science.gov (United States)

Shanks, L. V.; Kelly, D. C.; Meyers, S. R.

2015-12-01

Climatic cooling and expansion of Antarctic ice sheets was accompanied by a global reorganization in ocean circulation during the early Oligocene. Such a change in the ocean-climate system is expected to alter the pelagic ecosystem through elevated rates of extinction and increased biogeographic provincialism. A well documented, but poorly understood, example of this provincialism is the recurrence of unusual chalks composed of the nannofossil genus Braarudosphaera across the subtropical South Atlantic Ocean. Here we present preliminary findings from a study of the paleoceanographic conditions that fostered these Braarudosphaera "blooms" at Deep Sea Drilling Site 516 (Rio Grande Rise, southwestern Atlantic). Within the early Oligocene stratigraphy at this site, there are four chalky (recrystallized) layers in which braarudosphaerids compose ~70% of the nannofossil assemblages. Astronomical tuning was performed on conventional benthic foraminiferal δ18O and δ13C records encompassing the four layers to determine the timing of their recurrence. A strong astronomical rhythm is preserved with the blooms occurring during nodes in the theoretical obliquity solution. In addition, planktic foraminiferal stable isotope (δ18O, δ13C) records were generated for the study section using both secondary ion mass spectrometry (SIMS) and conventional gas-source isotope ratio mass spectrometry (IRMS). The SIMS-based δ13C record for the thermocline-dwelling genus Catapsydrax registers substantial (~1.5‰) decreases during the blooms, signaling pulsed increases in the upwelling of 13C-depleted waters. By contrast, the IRMS-based δ13C record for this same genus show no appreciable change in hydrographic conditions during the blooms. We attribute the invariant nature of the IRMS-based δ13C record to the smoothing effects of diagenesis. These results demonstrate how marine plankton respond to changing oceanographic conditions driven by astronomical forcing of ice-sheet dynamics.

Benthic foraminifera record and geochemical studies to reconstruct the recent (~400 ya) paleoenvironment of Tomales Bay, California

Science.gov (United States)

Flores, S. C.; Hill, T. M.; Russell, A. D.; Brooks, G.

2010-12-01

We are conducting investigations of calcareous benthic foraminifera acquired from Tomales Bay, California to reconstruct geochemical conditions of the bay for the past ~400 years, a time period of both natural and anthropogenic environmental change. Tomales Bay, located ~50km northwest of San Francisco, is a long (20.4 km), narrow (0.7 - 1.7 km) and shallow (2.0 - 6.0 m) bay that exhibits long-residence times and is stratified in the summer due to seasonal hypersalinity. Tomales Bay is a unique environment for climate and environmental change research because of the wide documented variability in carbonate parameters (pH, alkalinity, DIC) due to freshwater input from terrestrial sources that decreases aragonite and calcite saturation states. The historical record provided by benthic foraminiferal species and geochemistry, sedimentary carbon (TOC and TIC) analyses, and investigations of recent (Rose-Bengal stained) foraminifera are being utilized to constrain 3 major processes: 1) the range of temperature and salinity shifts over the past 400 years, 2) the relative dominance of marine- vs. fresh-water sources to the bay, and 3) the extent to which freshwater input and runoff may influence water chemistry (saturation state, Ω) with impacts on foraminiferal calcification. Four sediment cores were acquired in 2009 and 2010, and subsequently age-dated utilizing radiocarbon analyses (seven samples). Results indicate an increase in preservation of agglutinated versus calcareous foraminiferal tests (shells) since the mid-1900’s, and greater abundances of agglutinated tests found near freshwater sources. The major calcareous foraminifera present in the record include Elphidium hannai, Elphidium excavatum, Ammonia tepida, and Buccella frigida. Results from oxygen and carbon stable isotope analyses as well as total organic carbon (by weight) for all the cores will also be presented. These results will be compared to modern observations and instrumental records of

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.

with deepening of the mixed layer, since this species preferentially dwells in nutrient-rich upwelling waters. The population density of planktonic foraminifera ranges between 31 and 185 specimens per 10@u-3@@m@u3@@. The low absolute numbers of planktonic...

Biofilm and planktonic pneumococci demonstrate disparate immunoreactivity to human convalescent sera

Directory of Open Access Journals (Sweden)

Shivshankar Pooja

2011-11-01

Full Text Available Abstract Background Streptococcus pneumoniae (the pneumococcus is the leading cause of otitis media, community-acquired pneumonia (CAP, sepsis, and meningitis. It is now evident that S. pneumoniae forms biofilms during nasopharyngeal colonization; the former which facilitates persistence, the latter, a prerequisite for subsequent development of invasive disease. Proteomic evaluation of S. pneumoniae suggests the antigen profile available for host-recognition is altered as a consequence of biofilm growth. This has potentially meaningful implications in regards to adaptive immunity and protection from disseminated disease. We therefore examined the antigen profile of biofilm and planktonic pneumococcal cell lysates, tested their reactivity with human convalescent sera and that generated against biofilm pneumococci, and examined whether immunization with biofilm pneumococci protected mice against infectious challenge. Results Biofilm pneumococci have dramatically altered protein profiles versus their planktonic counterparts. During invasive disease the humoral immune response is skewed towards the planktonic protein profile. Immunization with biofilm bacteria does not elicit a strong-cross-reactive humoral response against planktonic bacteria nor confer resistance against challenge with a virulent isolate from another serotype. We identified numerous proteins, including Pneumococcal serine-rich repeat protein (PsrP, which may serve as a protective antigens against both colonization and invasive disease. Conclusion Differential protein production by planktonic and biofilm pneumococci provides a potential explanation for why individuals remain susceptible to invasive disease despite previous colonization events. These findings also strongly suggest that differential protein production during colonization and disease be considered during the selection of antigens for any future protein vaccine.

Xylella fastidiosa differentially accumulates mineral elements in biofilm and planktonic cells.

Science.gov (United States)

Cobine, Paul A; Cruz, Luisa F; Navarrete, Fernando; Duncan, Daniel; Tygart, Melissa; De La Fuente, Leonardo

2013-01-01

Xylella fastidiosa is a bacterial plant pathogen that infects numerous plant hosts. Disease develops when the bacterium colonizes the xylem vessels and forms a biofilm. Inductively coupled plasma optical emission spectroscopy was used to examine the mineral element content of this pathogen in biofilm and planktonic states. Significant accumulations of copper (30-fold), manganese (6-fold), zinc (5-fold), calcium (2-fold) and potassium (2-fold) in the biofilm compared to planktonic cells were observed. Other mineral elements such as sodium, magnesium and iron did not significantly differ between biofilm and planktonic cells. The distribution of mineral elements in the planktonic cells loosely mirrors the media composition; however the unique mineral element distribution in biofilm suggests specific mechanisms of accumulation from the media. A cell-to-surface attachment assay shows that addition of 50 to 100 µM Cu to standard X. fastidiosa media increases biofilm, while higher concentrations (>200 µM) slow cell growth and prevent biofilm formation. Moreover cell-to-surface attachment was blocked by specific chelation of copper. Growth of X. fastidiosa in microfluidic chambers under flow conditions showed that addition of 50 µM Cu to the media accelerated attachment and aggregation, while 400 µM prevented this process. Supplementation of standard media with Mn showed increased biofilm formation and cell-to-cell attachment. In contrast, while the biofilm accumulated Zn, supplementation to the media with this element caused inhibited growth of planktonic cells and impaired biofilm formation. Collectively these data suggest roles for these minerals in attachment and biofilm formation and therefore the virulence of this pathogen.

Surface zooplankton communities in the Indian sector of the Antarctic Ocean in early summer 1999/2000 observed with a Continuous Plankton Recorder

Directory of Open Access Journals (Sweden)

Haruko Umeda

2018-05-01

Full Text Available The first deployment of a Continuous Plankton Recorder (CPR on board the icebreaker Shirase was conducted during the 41st Japanese Antarctic Research Expedition (JARE in 1999/2000 austral summer in the Indian sector of the Antarctic Ocean. The CPR was towed horizontally at approximately 10m depth while the Shirase was steaming at about 14 knots across the Polar Front (PF. Mean total abundance of zooplankton for horizontal five nautical mile sample units was 168.1(SD : ±117.18 individuals with the maximum of 456 individuals. Zooplanktons were counted for 34 categories of species/taxa. Copepods occupied more than 90% of the total abundance in numbers. Oithona spp. was the most dominant group among copepods, representing 59% of the total zooplankton. Other numerically important categories were small-sized calanoids (copepodites and adults; 18.4%, and copepodites of Calanoides acutus and Calanus simillimus (8.2%. Latitudinal change of zooplankton abundance coincided with increasing/decreasing tends of temperature and salinity. Two different zooplankton assemblages were identified by cluster analysis and these assemblages seem to be closely related to different water characteristics, such as the of PF and areas of cold water masses. CPR is considered to be an ideal tool for long term monitoring of surface zooplankton communities.

A 130 year record of pollution in the Suances estuary (southern Bay of Biscay): Implications for environmental management

Energy Technology Data Exchange (ETDEWEB)

Irabien, M.J. [Departamento de Mineralogia y Petrologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/EHU, Apartado 644, 48080 Bilbao (Spain)], E-mail: mariajesus.irabien@ehu.es; Cearreta, A. [Departamento de Estratigrafia y Paleontologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/EHU, Apartado 644, 48080 Bilbao (Spain); Leorri, E. [Departamento de Estratigrafia y Paleontologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/EHU, Apartado 644, 48080 Bilbao (Spain); Sociedad de Ciencias Aranzadi, Zorroagagaina kalea 11, 20014 Donostia-San Sebastian (Spain); Gomez, J. [Departamento de Ciencias Medicas y Quirurgicas, Facultad de Medicina, Universidad de Cantabria, Avda Herrera Oria s/n, 39011 Santander (Spain); Viguri, J. [Departamento de Ingenieria Quimica y Quimica Inorganica, ETSIIT, Universidad de Cantabria, Avda Los Castros s/n, 39005 Santander (Spain)

2008-10-15

Geochemical composition (Al, Zn, Pb, Cd, Cu, Ni, Cr and As) and foraminiferal assemblages in surface and core sediments were determined to assess the current situation and the recent environmental transformation of the Suances estuary (southern Bay of Biscay, Spain). Dating of the historical record has been achieved using isotopic analysis ({sup 210}Pb, {sup 137}Cs) and two benchmark events such as the beginning of the mineral exploitation in the Reocin Pb-Zn deposits and the evolution of the chlor-alkali industry (inputs of Hg). Concentrations of Zn, Pb and Cd in both surface and core samples are remarkably higher than background values, reflecting the existence of significant amounts of polluted materials. The dramatic environmental impact of this pollution is clearly recorded by the change of the foraminiferal assemblages that even reach an afaunal stage during recent decades. Application of two different sets of Sediment Quality Guidelines confirm that they exert potential risk to the environment, and therefore if dredged they should need specific management measures. The results provide a reference database to monitor future environmental changes in the Suances estuary, particularly as regards the contaminated sediment storage and the re-colonization by autochtonous meiofauna.

A 130 year record of pollution in the Suances estuary (southern Bay of Biscay): Implications for environmental management

International Nuclear Information System (INIS)

Irabien, M.J.; Cearreta, A.; Leorri, E.; Gomez, J.; Viguri, J.

2008-01-01

Geochemical composition (Al, Zn, Pb, Cd, Cu, Ni, Cr and As) and foraminiferal assemblages in surface and core sediments were determined to assess the current situation and the recent environmental transformation of the Suances estuary (southern Bay of Biscay, Spain). Dating of the historical record has been achieved using isotopic analysis ( 210 Pb, 137 Cs) and two benchmark events such as the beginning of the mineral exploitation in the Reocin Pb-Zn deposits and the evolution of the chlor-alkali industry (inputs of Hg). Concentrations of Zn, Pb and Cd in both surface and core samples are remarkably higher than background values, reflecting the existence of significant amounts of polluted materials. The dramatic environmental impact of this pollution is clearly recorded by the change of the foraminiferal assemblages that even reach an afaunal stage during recent decades. Application of two different sets of Sediment Quality Guidelines confirm that they exert potential risk to the environment, and therefore if dredged they should need specific management measures. The results provide a reference database to monitor future environmental changes in the Suances estuary, particularly as regards the contaminated sediment storage and the re-colonization by autochtonous meiofauna

lower and Middle Miocene Foraminiferal Paleoecology of Southwest Sinai Area, Egypt

International Nuclear Information System (INIS)

El Ashwah, A.A.E.; Mandur, M.M.; Obeid, F.L.

2005-01-01

The planktonic and benthonic foraminifera content of the lower and middle miocene successions exposed at southwest Sinai in Egypt have been studied. One hundred and thirty three foraminifera species were identified (30 planktonic species and 103 benthonic species). This study aims to contribute in the understanding of the paleoecology, paleobathymetry and tectonic history of these sedimentary sequences. These sediments are subdivided into four rock units, from base to top, as follow: Nukhul, Rudeis, Kareem and Balayim formations. According to the foraminifera content the studied successions are subdivided into five eco zones. The environment of each ec ozone is deduced. These environments point to outer neritic for the Nukhul formation, middle to inner neritic for the Rudeis formation, inner to littoral neritic for the Kareem formation and littoral neritic for the Belayim formation. A proposed paleobathymetric curve is presented. The interpretation of this curve helped to deduce the tectonic history of the lower and Middle Miocene sediments in the studied area

The paleoclimatic events and cause in the Okinawa Trough during 50 kaBP

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Planktonic foraminiferal d18O record for core DGKS9603 from the Okinawa Trough shows a series of climatic fluctuations and sudden cooling events in short time scale during 50 kaBP, which appear to correlate closely to the Younger Dryas and Heinrich events H1-5 recorded in Chine-se loess, the South China Sea, the North Atlantic cores and the Greenland ice cores. Three polarity reversal events, cor-relating to Gothenburg, Mungo and Laschamp events, ap-proximately correspond to Heinrich events H1, H3 and H5 respectively, which could be a cause of global climate changes. The d18O curve of the Okinawa Trough is well asso-ciated with the grain size record of the Lijiayuan loess profile in northwestern China and is somewhat different from the climate fluctuations documented in the Greenland ice cores. These correlation results indicate that regional factors play an important role in controlling the climate changes in the East Asia, and the East Asian Monsoon could be the promi-nent regional controlling factor.

Smoothing a Piecewise-Smooth: An Example from Plankton Population Dynamics

DEFF Research Database (Denmark)

Piltz, Sofia Helena

2016-01-01

In this work we discuss a piecewise-smooth dynamical system inspired by plankton observations and constructed for one predator switching its diet between two different types of prey. We then discuss two smooth formulations of the piecewise-smooth model obtained by using a hyperbolic tangent funct...... function and adding a dimension to the system. We compare model behaviour of the three systems and show an example case where the steepness of the switch is determined from a comparison with data on freshwater plankton....

Cenozoic planktonic marine diatom diversity and correlation to climate change.

Directory of Open Access Journals (Sweden)

David Lazarus

Full Text Available Marine planktonic diatoms export carbon to the deep ocean, playing a key role in the global carbon cycle. Although commonly thought to have diversified over the Cenozoic as global oceans cooled, only two conflicting quantitative reconstructions exist, both from the Neptune deep-sea microfossil occurrences database. Total diversity shows Cenozoic increase but is sample size biased; conventional subsampling shows little net change. We calculate diversity from a separately compiled new diatom species range catalog, and recalculate Neptune subsampled-in-bin diversity using new methods to correct for increasing Cenozoic geographic endemism and decreasing Cenozoic evenness. We find coherent, substantial Cenozoic diversification in both datasets. Many living cold water species, including species important for export productivity, originate only in the latest Miocene or younger. We make a first quantitative comparison of diatom diversity to the global Cenozoic benthic ∂(18O (climate and carbon cycle records (∂(13C, and 20-0 Ma pCO2. Warmer climates are strongly correlated with lower diatom diversity (raw: rho = .92, p.9, detrended r>.6, all p<.001, but only weakly over the earlier Cenozoic, suggesting increasingly strong linkage of diatom and climate evolution in the Neogene. Our results suggest that many living marine planktonic diatom species may be at risk of extinction in future warm oceans, with an unknown but potentially substantial negative impact on the ocean biologic pump and oceanic carbon sequestration. We cannot however extrapolate our my-scale correlations with generic climate proxies to anthropogenic time-scales of warming without additional species-specific information on proximate ecologic controls.

Comparative transcriptome analysis of biofilm and planktonic cells of Bacillus cereus ATCC 14579

NARCIS (Netherlands)

Wijman, Janneke; Mols, M.; Tempelaars, Marcel; Abee, Tjakko

2015-01-01

Planktonic and biofilm cells of Bacillus cereus ATCC 14579 and ATCC 10987 were studied using microscopy and transcriptome analysis. By microscopy, clear differences could be observed between biofilm and planktonic cells as well as between the two strains. By using hierarchical clustering of the

Comparative transcriptome analysis of biofilm and planktonic cells of Bacillus cereus ATCC 10987

NARCIS (Netherlands)

Wijman, Janneke; Mols, M.; Tempelaars, Marcel; Abee, Tjakko

2015-01-01

Planktonic and biofilm cells of Bacillus cereus ATCC 14579 and ATCC 10987 were studied using microscopy and transcriptome analysis. By microscopy, clear differences could be observed between biofilm and planktonic cells as well as between the two strains. By using hierarchical clustering of the

Temporal variability of live (stained benthic foraminiferal faunas in a river-dominated shelf – Faunal response to rapid changes of the river influence (Rhône prodelta, NW Mediterranean

Directory of Open Access Journals (Sweden)

E. Legrand

2012-04-01

Full Text Available In the context of the French research project CHACCRA (Climate and Human-induced Alterations in Carbon Cycling at the River-seA connection, living (rose Bengal-stained benthic foraminifera were investigated at two stations (24 and 67 m depth in the Rhône prodelta (NW Mediterranean, Gulf of Lions. The aim of this study was to precise the response of benthic foraminiferal faunas to temporal changes of the Rhône River inputs (e.g. organic and terrigeneous material. Each site was sampled in April 2007, September 2007, May 2008 and December 2008, permitting to observe foraminiferal faunas of the 63–150 and >150 μm size fractions under a wide range of environmental conditions. Obvious variations in foraminiferal faunal composition were observed during the four investigated periods at the shallowest Station A located in the close vicinity of the Rhône River mouth. After major Rhône River flood events, different colonisation stages were observed with foraminiferal faunas responding with an opportunistic strategy few days to weeks after the creation of a peculiar sedimentary environment (Leptohalysis scottii, May 2008 or high organic matter supplies (Ammonia tepida, December 2008. Under more stable conditions, relatively diverse and equilibrated faunas grew in the sediments. Species benefited from noticeable input of riverine phytodetritus to the sediment during spring bloom conditions (April 2007; e.g. Bolivina dilatata, Nonionella stella, Stainforthia fusiformis, or high amounts of still bio-available organic matter under more oligotrophic conditions (September 2007; e.g. Ammonia tepida, Psammosphaera fusca. The reduced influence of the Rhône River input at the farther Station N led to less contrasted environmental conditions during the four sampling periods, and so to less obvious variations in foraminiferal faunal composition. During reduced riverine influence (i.e. low Rhône discharge, species able to feed on fresh phytodetritus (e

Ammolagena clavata (Jones and Parker, 1860), an agglutinated benthic foraminiferal species - first report from the Recent sediments, Arabian Sea, Indian Ocean region

Digital Repository Service at National Institute of Oceanography (India)

Nigam, R.; Mazumder, A.; Saraswat, R.

The rare presence of the agglutinated foraminiferal species Ammolagena clavata is presented for the first time from the Recent sediments of the Indian Ocean region. This species has previously been reported in Recent sediments from all other oceans...

Assessment of Nuclear Power Plant Impact to the Environment: Effect of Sea Water Temperature Increase on Plankton Population

International Nuclear Information System (INIS)

Tjahaja, I P; Pujadi; Supriharyono; Aviati, N; Ruswahyun; Busono, H

1996-01-01

Research to study the effect of sea water temperature increase on plankton population had been carried out to predict nuclear power plant impact to the environment. Plankton collected from Jepara waters, Muria Peninsula, was grown on growth medium i.e. sea water enriched with silicate fertilizer. Plankton growth was maintained at temperature varied from 34oC to 46oC and the amount of plankton individu was counted twice a day until it was reduced about 95%. The results showed that the reduction of amount of plankton individu occurred on the medium with temperature above the ambient temperature (34oC). The rate of reduction is linear to the temperature increase. There is no plankton survived at temperature above 40oC for more than 24 hours

Xylella fastidiosa differentially accumulates mineral elements in biofilm and planktonic cells.

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Paul A Cobine

Full Text Available Xylella fastidiosa is a bacterial plant pathogen that infects numerous plant hosts. Disease develops when the bacterium colonizes the xylem vessels and forms a biofilm. Inductively coupled plasma optical emission spectroscopy was used to examine the mineral element content of this pathogen in biofilm and planktonic states. Significant accumulations of copper (30-fold, manganese (6-fold, zinc (5-fold, calcium (2-fold and potassium (2-fold in the biofilm compared to planktonic cells were observed. Other mineral elements such as sodium, magnesium and iron did not significantly differ between biofilm and planktonic cells. The distribution of mineral elements in the planktonic cells loosely mirrors the media composition; however the unique mineral element distribution in biofilm suggests specific mechanisms of accumulation from the media. A cell-to-surface attachment assay shows that addition of 50 to 100 µM Cu to standard X. fastidiosa media increases biofilm, while higher concentrations (>200 µM slow cell growth and prevent biofilm formation. Moreover cell-to-surface attachment was blocked by specific chelation of copper. Growth of X. fastidiosa in microfluidic chambers under flow conditions showed that addition of 50 µM Cu to the media accelerated attachment and aggregation, while 400 µM prevented this process. Supplementation of standard media with Mn showed increased biofilm formation and cell-to-cell attachment. In contrast, while the biofilm accumulated Zn, supplementation to the media with this element caused inhibited growth of planktonic cells and impaired biofilm formation. Collectively these data suggest roles for these minerals in attachment and biofilm formation and therefore the virulence of this pathogen.

Major events in Neogene oxygen isotopic records

International Nuclear Information System (INIS)

Kennett, J.P.; Hodell, D.A.

1986-01-01

Changes in oxygen isotopic ratios of foraminiferal calcite during the cainozoic have been one of the primary tools for investigating the history of Arctic and Antarctic glaciation, although interpretations of the oxygen isotopic record differ markedly. The ambiguity in interpretation results mainly from the partitioning of temperature from ice volume effects in delta 18 O changes. Oxygen isotopic records for the Cainozoic show an increase in delta 18 O values towards the present, reflecting gradual cooling and increased glaciation of the Earth's climate since the late Cretaceous. A variety of core material from the South Atlantic and South-west Pacific oceans are investigated. This composite data represents one of the most complete available with which to evaluate the evolution of glaciation during the Neogene. Expansion of ice shelves in Antarctica undoubtedly accompanied the increased glaciation of the northern hemisphere, since eustatic sea-level lowering would positively reinforce ice growth on Antarctica

The onset of the 'Ordovician Plankton Revolution' in the late Cambrian

DEFF Research Database (Denmark)

Servais, Thomas; Perrier, Vincent; Danelian, Taniel

2016-01-01

Positive Carbon Isotope Excursion δ13Ccarb (SPICE) event in the late Cambrian (Paibian Stage, Furongian Series) has been related to a major increase in atmospheric O2 (from 10-18% to some 20 - 29%) and to increased oceanic nutrient availability. Here we analyze the diversification of the planktonic groups...... during the late Cambrian and Early Ordovician, in particular in relation to the SPICE event. Our analyses include the changing diversities of the phytoplankton (acritarchs), diverse groups of zooplankton (e.g., radiolarians, graptolites, chitinozoans) and the switch to a planktonic mode of life of fossil...... of the different planktonic organisms can be related directly to the SPICE event. However, a long term (10-20millionyears) oxygenation pulse related to the SPICE event might have fuelled the explosion of phytoplankton diversity observed in the latest Cambrian-Early Ordovician that led to completely modified...

Eocene to Oligocene benthic foraminiferal isotopic record in the Bay of Biscay

International Nuclear Information System (INIS)

Miller, K.G.; Curry, W.B.

1982-01-01

Oxygen and carbon isotopic records of Eocene to Oligocene benthic foraminifera from two Bay of Biscay Deep Sea Drilling Project sites are presented. The delta 18 O figures for benthic foraminifera are significantly higher than those previously reported from deeper North Atlantic sites, the differences arising it is believed from diagenetic alteration of the sediments in the deeper-buried sites. (U.K.)

Plankton Dynamics and Mesoscale Turbulence

Science.gov (United States)

2010-06-29

transformation of inorganic materials and light into living matter by photosynthesis) is operated mainly by small, unicellular algae that float freely in the...Aquatic ecosystems are characterized by the essential role played by fluid dynamics. The small organisms which compose the plankton are advected by the...surrounding flow and must cope with environmental currents, turbulence, and waves. And those organisms which anchor themselves to the rocks and to the

Factors Affecting Catalase Expression in Pseudomonas aeruginosa Biofilms and Planktonic Cells

OpenAIRE

Frederick, Jesse R.; Elkins, James G.; Bollinger, Nikki; Hassett, Daniel J.; McDermott, Timothy R.

2001-01-01

Previous work with Pseudomonas aeruginosa showed that catalase activity in biofilms was significantly reduced relative to that in planktonic cells. To better understand biofilm physiology, we examined possible explanations for the differential expression of catalase in cells cultured in these two different conditions. For maximal catalase activity, biofilm cells required significantly more iron (25 μM as FeCl3) in the medium, whereas planktonic cultures required no addition of iron. However, ...

Bacteriophage-antibiotic synergism to control planktonic and biofilm ...

African Journals Online (AJOL)

Bacteriophage-antibiotic synergism to control planktonic and biofilm producing clinical isolates of Pseudomonas aeruginosa. Amina Amal Mahmoud Nouraldin, Manal Mohammad Baddour, Reem Abdel Hameed Harfoush, Sara AbdelAziz Mohamed Essa ...

Research highlights: impacts of microplastics on plankton.

Science.gov (United States)

Lin, Vivian S

2016-02-01

Each year, millions of metric tons of the plastic produced for food packaging, personal care products, fishing gear, and other human activities end up in lakes, rivers, and the ocean. The breakdown of these primary plastics in the environment results in microplastics, small fragments of plastic typically less than 1-5 mm in size. These synthetic particles have been detected in all of the world's oceans and also in many freshwater systems, accumulating in sediment, on shorelines, suspended in surface waters, and being ingested by plankton, fish, birds, and marine mammals. While the occurrence of plastics in surface waters has been surveyed in a number of studies, the impacts of microplastics on marine organisms are still being elucidated. This highlight features three recent publications that explore the interactions of microplastics with planktonic organisms to clarify the effects of these pollutants on some of the ocean's smallest and most important inhabitants.

Modeling the distribution of colonial species to improve estimation of plankton concentration in ballast water

Science.gov (United States)

Rajakaruna, Harshana; VandenByllaardt, Julie; Kydd, Jocelyn; Bailey, Sarah

2018-03-01

The International Maritime Organization (IMO) has set limits on allowable plankton concentrations in ballast water discharge to minimize aquatic invasions globally. Previous guidance on ballast water sampling and compliance decision thresholds was based on the assumption that probability distributions of plankton are Poisson when spatially homogenous, or negative binomial when heterogeneous. We propose a hierarchical probability model, which incorporates distributions at the level of particles (i.e., discrete individuals plus colonies per unit volume) and also within particles (i.e., individuals per particle) to estimate the average plankton concentration in ballast water. We examined the performance of the models using data for plankton in the size class ≥ 10 μm and test ballast water compliance using the above models.

Disruptive selection and bet-hedging in planktonic Foraminifera: Shell morphology as predictor of extinctions

Directory of Open Access Journals (Sweden)

Manuel F. G. Weinkauf

2014-10-01

Full Text Available Extinction is a remarkably difficult phenomenon to study under natural conditions. This is because the outcome of stress exposure and associated fitness reduction is not known until the extinction occurs and it remains unclear whether there is any phenotypic reaction of the exposed population that can be used to predict its fate. Here we take advantage of the fossil record, where the ecological outcome of stress exposure is known. Specifically, we analyze shell morphology of planktonic Foraminifera in sediment samples from the Mediterranean, during an interval preceding local extinctions. In two species representing different plankton habitats, we observe shifts in trait state and decrease in variance in association with non-terminal stress, indicating stabilizing selection. At terminal stress levels, immediately before extinction, we observe increased growth asymmetry and trait variance, indicating disruptive selection and bet-hedging. The pre-extinction populations of both species show a combination of trait states and trait variance distinct from all populations exposed to non-terminal levels of stress. This finding indicates that the phenotypic history of a population may allow the detection of threshold levels of stress, likely to lead to extinction. It is thus an alternative to population dynamics in studying and monitoring natural population ecology.

Foraminiferal production and monsoonal upwelling in the Arabian sea: evidence from sediment traps

Digital Repository Service at National Institute of Oceanography (India)

Curry, W.B.; Ostermann, D.R.; Guptha, M.V.S.; Ittekkot, V.

Planktonic foraminifera collected in sediment traps in the Arabian Sea during 1986 and 1987 responded to the southern Asian monsoon with changes in productivity, relative abundance of species and isotopic shell chemistry. Most species...

Norwegian deep-water coral reefs: cultivation and molecular analysis of planktonic microbial communities.

Science.gov (United States)

Jensen, Sigmund; Lynch, Michael D J; Ray, Jessica L; Neufeld, Josh D; Hovland, Martin

2015-10-01

Deep-sea coral reefs do not receive sunlight and depend on plankton. Little is known about the plankton composition at such reefs, even though they constitute habitats for many invertebrates and fish. We investigated plankton communities from three reefs at 260-350 m depth at hydrocarbon fields off the mid-Norwegian coast using a combination of cultivation and small subunit (SSU) rRNA gene and transcript sequencing. Eight months incubations of a reef water sample with minimal medium, supplemented with carbon dioxide and gaseous alkanes at in situ-like conditions, enabled isolation of mostly Alphaproteobacteria (Sulfitobacter, Loktanella), Gammaproteobacteria (Colwellia) and Flavobacteria (Polaribacter). The relative abundance of isolates in the original sample ranged from ∼ 0.01% to 0.80%. Comparisons of bacterial SSU sequences from filtered plankton of reef and non-reef control samples indicated high abundance and metabolic activity of primarily Alphaproteobacteria (SAR11 Ia), Gammaproteobacteria (ARCTIC96BD-19), but also of Deltaproteobacteria (Nitrospina, SAR324). Eukaryote SSU sequences indicated metabolically active microalgae and animals, including codfish, at the reef sites. The plankton community composition varied between reefs and differed between DNA and RNA assessments. Over 5000 operational taxonomic units were detected, some indicators of reef sites (e.g. Flavobacteria, Cercozoa, Demospongiae) and some more active at reef sites (e.g. Gammaproteobacteria, Ciliophora, Copepoda). © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Rethinking CCD's Significance in Estimating Late Neogene Whole Ocean Carbonate Budget

Science.gov (United States)

Si, W.; Rosenthal, Y.

2017-12-01

The global averaged calcite compensation depth (CCD) record is conventionally used to reconstruct two correlatable parameters of the carbonate system - the alkalinity budget of the ocean and/or the saturation state of the ocean. Accordingly, the available CCD reconstructions have been interpreted to suggest either relative stable (Pearson and Palmer, 2000) or increased alkalinity of the ocean over the past 15 Ma (Tyrrell and Zeebe, 2004; Pälike et al., 2012). However, CCD alone is insufficient to constrain the carbonate system because the weathering flux of alkalinity into the ocean is not only balanced by CaCO3 dissolution on the seafloor but also by the biologic production in the euphotic zone and, the CCD records cannot be readily interpreted as changes in either process. Here, we present evidence of the co-evolution of surface CaCO3 production and deepsea dissolution through the late Neogene. By examining separately the mass accumulation rates (MAR) of coccoliths, planktonic foraminifera, and quantifying dissolution (using a proxy revised from Broecker et al., 1999) in seventeen deepsea cores from multiple depth-transects, we find that 1) MAR of dissolution-resistant coccoliths was substantially higher in the mid Miocene and declining on a global scale towards the present; 2) unlike coccoliths, MAR of planktonic foraminifera, shows no apparent secular trend through that time; 3) the revised dissolution index, shows significantly improved preservation of planktonic foraminiferal shells over that time, particularly at intermediate water depth and exhibits close association between changes in preservation with key climatic events. Our new records have two immediate implications. First, the substantially weakened pelagic biogenic carbonate production from mid Miocene to present alone could account for the improved preservation of deepsea carbonates without calling for a scenario of increased weathering input. Second, with the constrain of global averaged CCD

KOEFISIEN SAPROBIK PLANKTON DI PERAIRAN EMBUNG UNIVERSITAS NEGERI SEMARANG

Directory of Open Access Journals (Sweden)

AS Awaludin

2016-04-01

Full Text Available Embung Universitas Negeri Semarang dibangun dengan tujuan sebagai tempat penampungan air hujan dan penyerapan air di Universitas Negeri Semarang dan mempunyai kapasitas penampungan air 5.000 m3. Keberadaan embung tersebut menciptakan suatu ekosistem baru yaitu tempat hidup ikan-ikan di dalamnya. Saprobitas perairan digunakan untuk mengetahui keadaan kualitas air yang diakibatkan adanya penambahan bahan organik dalam suatu  perairan yang biasanya indikatornya adalah jumlah dan susunan spesies dari organisme di dalam perairan tersebut. Plankton dapat digunakan sebagai bioindikator perairan karena memiliki tingkat kepekaan tinggi terhadap adanya pencemaran. Penelitian ini menggunakan rancangan eksplorasi dengan metode survai, dimana penetapan stasiun pengambilan sampel dengan purposive sampling. Penempatan stasiun didasarkan atas perkiraan beban pencemar dan aktivitas yang terdapat di sepanjang aliran dari (stasiun satu sampai sembilan, pengambilan sampel dilakukan sebanyak 3 kali dengan selang waktu 2 minggu. Data dalam penelitian ini adalah data kuantitatif berupa jumlah jenis spesies plankton yang ditemukan pada penelitian ini kemudian diinterpretasikan pada tabel hubungan antara koefisien saprobitas perairan dengan tingkat pencemaran perairan. Berdasarkan perhitungan dan analisis nilai koefisien saprobik dari stasiun satu sampai sampai sembilan didapatkan nilai koefisien saprobik plankton berkisar antara -0,4 s/d 0,9. Berdasarkan kriteria tingkat pencemaran menunjukkan bahwa Embung Universitas Negeri Semarang berada dalam kondisi tercemar ringan sampai dengan sedang.Universitas Negeri Semarang Reservoir was constructed for the purpose as rain water reservoirs and water absorption in Universitas Negeri Semarang and has a water storage capacity of 5,000 cubic meters. The existence of such ponds are creating a new ecosystem where fish live in it. Saprobic waters are used to determine the state of water quality resulting from the addition of

Antimicrobial activity of vanadium chloroperoxidase on planktonic Streptococcus mutans cells and Streptococcus mutans biofilms

NARCIS (Netherlands)

Hoogenkamp, M.A.; Crielaard, W.; ten Cate, J.M.; Wever, R.; Hartog, A.F.; Renirie, R.

2009-01-01

The aim of this study was to investigate the antimicrobial activity of vanadium chloroperoxidase (VCPO) reaction products on planktonic and biofilm cellsof Streptococcus mutans C180-2. Planktonic and biofilm cells were incubated in a buffered reaction mixture containing VCPO, halide (either chloride

Mixotrophy in the marine plankton

DEFF Research Database (Denmark)

Stoecker, Diane K.; Hansen, Per Juel; Caron, David

2017-01-01

Mixotrophs are important components of the bacterioplankton, phytoplankton, microzooplankton, and (sometimes) zooplankton in coastal and oceanic waters. Bacterivory among the phytoplankton may be important for alleviating inorganic nutrient stress and may increase primary production in oligotrophic...... waters. Mixotrophic phytoflagellates and dinoflagellates are often dominant components of the plankton during seasonal stratification. Many of the microzooplankton grazers, including ciliates and Rhizaria, are mixotrophic owing to their retention of functional algal organelles or maintenance of algal...

Over 100 years of environmental change recorded by foraminifers and sediments in a large Gulf of Mexico estuary, Mobile Bay, AL, USA

Science.gov (United States)

Osterman, Lisa E.; Smith, Christopher G.

2012-01-01

The marine microfauna of Mobile Bay has been profoundly influenced by the development and expansion of the primary shipping channel over the last ˜100 years. Foraminifers and sediments from seven box cores with excess lead-210 chronology document that channel dredging and spoil disposal have altered circulation, reduced estuarine mixing, changed sedimentation patterns, and caused a faunal turnover within the bay. Beginning in the late 1800s, changes in estuarine mixing allowed for greater low-pH freshwater influence in the bay, and ultimately began environmental changes that resulted in the loss of calcareous foraminifers. By the early 1900s, box cores throughout Mobile Bay record a ˜ 100-year trend of increasing calcareous test dissolution that continues to the present. Since the completion of the current shipping channel in the 1950s, restricted tidal flushing and increased terrestrial organic matter, documented by carbon-to-nitrogen ratios, stimulated an increase in agglutinated foraminiferal densities. However, in deeper areas of the bay, hypoxic water has negatively impacted the marine microfauna. Comparisons of the present-day foraminiferal assemblage with foraminifers collected in the early 1970s indicate that the continued biologic loss of calcareous foraminifers in the bay has allowed the introduction of a new agglutinated foraminiferal species into the bay.

High motility reduces grazing mortality of planktonic bacteria

DEFF Research Database (Denmark)

Matz, Carsten; Jurgens, K.

2005-01-01

We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated...... size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 mum(3). Grazing mortality was lowest for cells of >0.5 mum(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (less than or equal to0.1 mum......(3), >50 mum s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing....

Mesh size effects on assessments of planktonic hydrozoan abundance and assemblage structure

Science.gov (United States)

Nogueira Júnior, Miodeli; Pukanski, Luis Eduardo de M.; Souza-Conceição, José M.

2015-04-01

The choice of appropriate mesh-size is paramount to accurately quantify planktonic assemblages, however there is no such information available for hydrozoans. Here planktonic hydrozoan abundance and assemblage structure were compared using 200 and 500 μm meshes at Babitonga estuary (S Brazil), throughout a year cycle. Species richness and Shannon-Wiener diversity were higher in the 200 μm mesh, while evenness was typically higher in the 500 μm. Assemblage structure was significantly different between meshes (PERMANOVA, P 8 mm in October. These results suggest that both meshes have their drawbacks and the best choice would depend on the objectives of each study. Nevertheless species richness, total abundances and most taxa were better represented by the 200 μm mesh, suggesting that it is more appropriate to quantitatively sample planktonic hydrozoan assemblages.

Planktonic algae and cyanoprokaryotes as indicators of ecosystem ...

African Journals Online (AJOL)

Planktonic algae and cyanoprokaryotes as indicators of ecosystem quality in the Mooi River system in the North-West Province, South Africa. ... is important for maintaining the quality of potable water of Potchefstroom and surrounding areas.

Hydro-plankton characteristics and their relationship with sardine and anchovy distributions on the French shelf of the Bay of Biscay

Directory of Open Access Journals (Sweden)

Pierre Petitgas

2006-06-01

Full Text Available The spatial pattern in hydro-plankton and fish distributions and their relationship were analysed based on the spring 2000 fisheries acoustic survey. The importance of this survey was that it was a multi-disciplinary platform which collected an extensive set of parameters in the hydro-plankton leading to a potentially finer description of hydro-plankton conditions and fish habitats. More than 50 variables were measured on a grid of stations, in four compartments of the ecosystem: hydrology, nutrients, primary producers and meso-zooplankton. First, a joint analysis of all hydro-plankton compartments was performed using multiple factor analysis (MFA. The method was used to estimate a compromise factorial space common to all compartments in which the stations were grouped by hierarchical clustering. The groups were represented spatially and a strong spatial pattern was evidenced. The fish and their spawned eggs were sampled along transect lines using acoustics and CUFES (continuous underway fish egg samplers. The distribution of the fish and their eggs was analysed in relation to the hydro-plankton groups of stations and difference in fish density across hydro-plankton conditions was tested by a pair-wise multiple comparison procedure. Anchovy was associated with a lesser number of hydro-plankton conditions than sardine. Eggs of both species were also associated with a lesser number of conditions than the fish. Finally, the gain provided by using the extensive set of hydro-plankton parameters for mapping large-scale hydro-plankton conditions was analysed in comparison with the situation in which a small set of parameters was available. The extensive set of parameters allowed more hydro-plankton conditions to be identified but only in the coastal area and not on the shelf. Size fractionated chlorophyll was determinant for tracking river plume hydro-plankton condition. However, the fish did not respond to the variety of the coastal hydro-plankton

COPEPOD: The Coastal & Oceanic Plankton Ecology, Production, & Observation Database

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal & Oceanic Plankton Ecology, Production, & Observation Database (COPEPOD) provides NMFS scientists with quality-controlled, globally distributed...

Continuous daylight in the high-Arctic summer supports high plankton respiration rates compared to those supported in the dark

KAUST Repository

Mesa, Elena; Delgado-Huertas, Antonio; Carrillo-de-Albornoz, Paloma; Garcí a-Corral, Lara S.; Sanz-Martí n, Marina; Wassmann, Paul; Reigstad, Marit; Sejr, Mikael; Dalsgaard, Tage; Duarte, Carlos M.

2017-01-01

Plankton respiration rate is a major component of global CO2 production and is forecasted to increase rapidly in the Arctic with warming. Yet, existing assessments in the Arctic evaluated plankton respiration in the dark. Evidence that plankton

Plankton biodiversity of Dharamtar creek adjoining Mumbai harbour

Digital Repository Service at National Institute of Oceanography (India)

Tiwari, L.R.; Nair, V.R.

rich plankton community. However, recent industrial development along the banks of creek may pose the problem due to waste disposal into this creek system. Losses of marine life diversity are largely the results of conflicting uses, in particular...

Size distribution of planktonic autotrophy and microheterotrophy in DeGray Reservoir, Arkansas

International Nuclear Information System (INIS)

Kimmel, B.L.; Groeger, A.W.

1983-01-01

Naturally occurring assemblages of phytoplankton and bacterioplankton were radiolabelled with sodium 14 C-bicarbonate and sodium 3 H-acetate and size fractionated to determine the size structure of planktonic autotrophy and microheterotrophy in DeGray Reservoir, an oligotrophic impoundment of the Caddo River in south-central Arkansas. Size distributions of autotrophy and microheterotrophy were remarkably uniform seasonally, vertically within the water column, and along the longitudinal axis of the reservoir despite significant changes in environmental conditions. Planktonic autotrophy was dominated by small algal cells with usually >50% of the photosynthetic carbon uptake accounted for by organisms 75% of the planktonic microheterotrophy. Longitudinal patterns in autotrophic and microheterotrophic activities associated with >3-μm and >1-μm size fractions, respectively, suggest an uplake to downlake shift from riverine to lacustrine environmental influences within the reservoir. 83 references, 7 figures

Cultivation of seaweed Gracilaria lemaneiformis enhanced biodiversity in a eukaryotic plankton community as revealed via metagenomic analyses.

Science.gov (United States)

Chai, Zhao Yang; He, Zhi Li; Deng, Yun Yan; Yang, Yu Feng; Tang, Ying Zhong

2018-02-01

Plankton diversity reflects the quality and health of waters and should be monitored as a critical feature of marine ecosystems. This study applied a pair of 28S rRNA gene-specific primers and pyrosequencing to assess the effects of large-scale cultivation of the seaweed Gracilaria lemaneiformis on the biodiversity of eukaryotic plankton community in the coastal water of Guangdong, China. With 1 million sequences (2,221 operational taxonomic units [OTUs]) obtained from 51 samples, we found that the biodiversity of eukaryotic plankton community was significantly higher in the seaweed cultivation area than that in the nearby control area as reflected in OTU richness, evenness (Shannon-Wiener index) and dominance (Simpson index) for total plankton community and its four subcategories when Gracilaria biomass reached the maximum, while no such a significant difference was observed before seaweed inoculation. Our laboratory experiment using an artificial phytoplankton community of nine species observed the same effects of Gracilaria exposure. Principal component analysis and principal coordinates analysis showed the plankton community structure in cultivation area markedly differed from the control area when Gracilaria biomass reached its maximum. Redundancy analysis showed that G. lemaneiformis was the critical factor in controlling the dynamics of eukaryotic plankton communities in the studied coastal ecosystem. Our results explicitly demonstrated G. lemaneiformis cultivation could enhance biodiversity of plankton community via allelopathy, which prevents one or several plankton species from blooming and consequently maintains a relatively higher biodiversity. Our study provided further support for using large-scale G. lemaneiformis cultivation as an effective approach for improving costal ecosystem health. © 2018 John Wiley & Sons Ltd.

Inorganic mercury (Hg2+ uptake by different plankton fractions of Andean Patagonian lakes (Argentina

Directory of Open Access Journals (Sweden)

Diéguez M.C.

2014-07-01

Full Text Available The species composition and the size structure of natural planktonic food webs may provide essential information to understand the fate of mercury and, in particular, the bioaccumulation pattern of Hg2+ in the water column of lake ecosystems. Heterotrophic and autotrophic picoplankton and phytoplankton are the most important entry points for Hg in aquatic ecosystems since they concentrate Hg2+ and MeHg from ambient water, making them available to planktonic consumers at higher trophic levels of lake food webs. In this investigation we studied the uptake of 197Hg2+ in natural plankton assemblages from four Andean lakes (Nahuel Huapi National Park, Patagonia, Argentina, comprised in the size fractions 0.2-2.7 μm (picoplankton, 0.2-20 μm (pico and nanoplankton and 20-50 μm (microplankton through experiments using Hg2+ labeled with 197Hg2+. The experimental results showed that the uptake of Hg2+ was highest in the smallest plankton fractions (0.2-2.7 μm and 0.2-20 μm compared to the larger fraction comprising microplankton (20-50 um. This pattern was consistent in all lakes, reinforcing the idea that among pelagic organisms, heterotrophic and autotrophic bacteria with the contribution of nanoflagellates and dinoflagellates constitute the main entry point of Hg2+ to the pelagic food web. Moreover, a significant direct relationship was found between the Hg2+ uptake and surface index of the planktonic fractions (SIf. Thus, the smaller planktonic fractions which bore the higher SI were the major contributors to the Hg2+ passing from the abiotic to the biotic pelagic compartments of these Andean lakes.

GLOBEC NEP Vertical Plankton Tow (VPT) Data, 1997-2001

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) California Current Program Vertical Plankton Tow (VPT) Data For more information, see...

Marine historical ecology at the Brijuni Islands, Croatia: preliminary results from down-core changes of foraminiferal assemblages

Science.gov (United States)

Vidovic, Jelena; Cosovic, Vlasta; Gallmetzer, Ivo; Haselmair, Alexandra; Zuschin, Martin

2015-04-01

The Late Holocene in the northern Adriatic is characterized by the eustatic peak of the sea-level rise, followed by the equilibrium between the regional tectonic subsidence and hydro-isostatic emergence and relatively stable sea level for a few thousand years. During this period the area experienced changes in sedimentation rate, food/oxygen availability in the benthic ecosystem and eutrophication with seasonal hypoxic and anoxic events. In order to reconstruct the marine paleoecology in the Brijuni Islands area during this period, a multidisciplinary study was carried out, including geochemical (TOC, trace metals, carbonate content), micropaleontological analyses (benthic foraminifera) and dating of sediments and mollusc shells. The principal aim of this study is to observe the effects of ecological shifts on foraminiferal assemblages during the Late Holocene. One core of 1.5 m length was taken at a sampling station south of Veli Brijuni Island, located within a marine protected area with no fishing/dredging pressure (Croatian national park). The core was sliced into smaller subsamples, and four sediment fractions of each subsample (63, 125, 250 and 500 µm) were analyzed for standard properties of the foraminiferal community (species richness, faunal composition, biodiversity indices), in comparison with relevant physical and geochemical properties of the sediment. The results concerning changes in foraminiferal species composition and abundance point to differences within the core: surface sediments are dominated by suspension feeders (Planorbulina mediterranensis, Lobatula lobatula, Cibicides variabilis, Cibicides refulgens), whereas deposit feeders (genera Textularia, Siphonaperta, Adelosina, Trioculina) appear in higher abundances at approximately 30 cm of the sediment depth and dominate down-core. Species richness in the first 30 cm is lower (10 to 34 species per sample) in comparison to the middle part of the core (39 to 53 species), and decreases again at

Emergent Patterns of Diversity and Dynamics in Natural Populations of Planktonic Vibrio Bacteria

Science.gov (United States)

2005-06-01

1973. Ecology of Vibrio parahemolyticus in mixed-template amplifications: formation, consequences and elimination by Chesapeake Bay. J. Bacteriol. 113...Science 1930 and Engineering DOCTORAL DISSERTATION Emergent Patterns of Diversity and Dynamics in Natural Populations of Planktonic Vibrio Bacteria by...DYNAMICS IN NATURAL POPULATIONS OF PLANKTONIC VIBRIO BACTERIA by Janelle Ren6e Thompson B.S. Biological Sciences, Stanford University 1998 M.S

Factors affecting egg ratios in planktonic rotifers

NARCIS (Netherlands)

Sarma, S.S.S.; Gulati, R.D.; Nandini, S.

2005-01-01

Edmondson’s egg ratio (number of amictic eggs per female) is an important life history variable, which has been in wide use to understand and predict patterns of population growth in planktonic rotifers under field conditions. It is also useful as an indicator of the health of rotifers under culture

Paleoenvironmental evolution based on benthic foraminifera biofacies of the Paraíba do Sul Deltaic Complex, eastern Brazil

Science.gov (United States)

Gasparini, Sarah Pereira; Vilela, Claudia Gutterres

2017-12-01

The paleoecology and distribution of benthic foraminiferal assemblages were analyzed in the core 2-MU-1-RJ well, drilled in the Paraíba do Sul Deltaic Complex, Rio de Janeiro (Brazil). An abundant assemblage was found in the upper portion of the well core, inferred to be pleistocenic deposits. The coastal dynamic was recognized from five biofacies based on clusters, the Planktonic/Benthic (P/B) ratios and indicator species distribution in the core. Several biofacies were identified along the core depending on the species dominance. From the bottom to the top of the core, the biofacies succession represents the environmental changes in the coastal area associated to sea-level oscillations. The biofacies ABP dominated by Ammonia parkinsoniana and Bolivina spp. and Pararotalia cananeiaensis represents an inner shelf environment; biofacies QP dominated by shelf miliolids species; biofacies PGH, dominated by P. cananeiaensis, Gavelinopsis praegeri, and Hanzawaia nitidula, represents the estuary complex with middle or outer shelf influence; biofacies QL represents hypersaline waters dominated by lagoonal miliolids; and biofacies HP characterized by Haynesina germanica and P. cananeiaensis is associated with paralic environments. Marine ingressions are recorded and those biofacies show the pleistocenic coastal hydrodinamic in the deltaic complex. The foraminiferal biofacies contribute with detailed information to sedimentary facies previously characterized in the study area by the reconstruction of paleoenvironment succession.

Physicochemical Constraints on the Distribution of Benthic Foraminiferal Cell Morphology in the Modern Ocean

Science.gov (United States)

Keating-Bitonti, C.; Payne, J.

2016-02-01

Patterns in the sizes and shapes of marine organisms often occur across latitude and water depth gradients as a function of metabolic constraints dictated by the physical environment. However, the environmental factors that maintain these gradients in morphology remain incompletely understood because several oceanographic variables of biological importance are intimately correlated, such as temperature, dissolved oxygen concentration, particulate organic carbon (POC) flux, and carbonate saturation. Benthic foraminifera, a diverse group of single-celled protists that occur in nearly all marine environments, provide an ideal opportunity to test statistically among the various hypothesized environmental controls on cell morphology. Here, we use over 7,000 occurrences of 541 species of recent benthic foraminifera that span more than 60 degrees of latitude and 1,600 meters of water depth around the North American continental margin to assess the relative contributions of temperature, oxygen availability, carbonate saturation, and POC flux on their size and volume-to-surface area ratio in the modern ocean. Seawater temperature and dissolved oxygen concentrations best predict both measures of benthic foraminiferal cell morphology from the North American continental margin. These same variables also explain morphological variations from the Pacific continental margin in isolation, but dissolved oxygen is absent from the best model for the Atlantic. Because our results concur with predictions from first principles of cell physiology, we interpret these findings to reflect the physiological selective pressures on cell morphology as determined by the physical environment. Moreover, these findings suggest that warming waters and the expansion of hypoxic zones associated with anthropogenic-induced climate change are more likely to impact benthic foraminiferal communities than changes in primary productivity or ocean acidification.

DINAMIKA KOMUNITAS PLANKTON DI PERAIRAN EKOSISTEM HUTAN BAKAU SEGARA ANAKAN YANG SEDANG BERUBAH (Plankton Dynamic in the Changing Mangrove Ecosystem of Segara Anakan Central Java

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Tjut Sugandawaty Djohan

2010-11-01

Full Text Available ABSTRAK Perairan hutan bakau Segara Anakan merupakan ekosistem yang sedang berubah karena sedimentasi yang tinggi sejak tahun 1980, dan telah mengakibatkan pendangkalan perainan dan mengganggu proses pasang surut. Perubahan ekosistem ini direspon oleh komunitas plankton. pada musim hujan tabun 2002 salinitas perairannya adalah 0 0/00' dan musim kemarau 20 – 32%. Perubahan komunitas plankton tersebut dicirikan hadimya komunitas baik phyto maupun zooplankton dominan sungai pada musim hujan, dan sebaliknya komunitas laut pada musim kemarau. Pada tahun 2004, karena pendangkalan di perairan Bondan, mudflat dan perairannya dikeruk. Penelitian ini bertujuan untuk mempelajari respon komunitas phyto dan zooplankton terhadap pernbanan ekosistem pada musim kemarau Agustus 2005 di daerah tangkapan ikan nelayan perairan Segara Anakan. Hasil menunjukkan bahwa ada peledakan kemelimpahan phytoplankton yang didommasi olehl populasi Chaetoceros di perairan Bondan dan Klaces sebanyak 206890 dan 397273 individu per 100 liter, dan populasi  Asterione/lajaponica meningkat sebanyak 69778 per 100 liter di perairan Cigatal. Peledakan kedua genus tersebut adalah merupakan respon phytoplankton terhadap meningkatnya kandungan PO4 di perairan oleh pengerukan sedimen di perairan Bondan. Kenaikan P04 di perairan berturut-berturut dari Bondan ke Cigatal sebesar 4,95 ppm, 5,88 ppm, dan 4,62 ppm. Pada musim kemarau, perairan Segara Anakan juga dicirikan dengan hadimya komunitas plankton sungai yaitu sebanyak 19 species phytoplankton, dan 9 spesies zooplankton. Peledakan populasi Chaetoceros tidak direspon oleh peledakan populasi zooplankton. Keadaan ini mencerminkan bahwa kualitas perairan Segara Anakan telah menurun.   ABSTRACT The mangrove ecosystem of Segara Anakan is in the process of changing to the freshwater-wetland due to the heavy sedimentation. This change was responded by the plankton communities. In the 2002 during the rainy season, the salinity

Early Eocene deep-sea benthic foraminiferal faunas: Recovery from the Paleocene Eocene Thermal Maximum extinction in a greenhouse world

Science.gov (United States)

Thomas, Ellen; D’haenens, Simon; Speijer, Robert P.; Alegret, Laia

2018-01-01

The early Eocene greenhouse world was marked by multiple transient hyperthermal events. The most extreme was the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma), linked to the extinction of the globally recognised deep-sea benthic foraminiferal Velasco fauna, which led to the development of early Eocene assemblages. This turnover has been studied at high resolution, but faunal development into the later early Eocene is poorly documented. There is no widely accepted early Eocene equivalent of the Late Cretaceous-Paleocene Velasco fauna, mainly due to the use of different taxonomic concepts. We compiled Ypresian benthic foraminiferal data from 17 middle bathyal-lower abyssal ocean drilling sites in the Pacific, Atlantic and Indian Oceans, in order to characterise early Eocene deep-sea faunas by comparing assemblages across space, paleodepth and time. Nuttallides truempyi, Oridorsalis umbonatus, Bulimina trinitatensis, the Bulimina simplex group, the Anomalinoides spissiformis group, pleurostomellids, uniserial lagenids, stilostomellids and lenticulinids were ubiquitous during the early Eocene (lower-middle Ypresian). Aragonia aragonensis, the Globocassidulina subglobosa group, the Cibicidoides eocaenus group and polymorphinids became ubiquitous during the middle Ypresian. The most abundant early Ypresian taxa were tolerant to stressed or disturbed environments, either by opportunistic behavior (Quadrimorphina profunda, Tappanina selmensis, Siphogenerinoides brevispinosa) and/or the ability to calcify in carbonate-corrosive waters (N. truempyi). Nuttallides truempyi, T. selmensis and other buliminids (Bolivinoides cf. decoratus group, Bulimina virginiana) were markedly abundant during the middle Ypresian. Contrary to the long-lived, highly diverse and equitable Velasco fauna, common and abundant taxa reflect highly perturbed assemblages through the earliest Ypresian, with lower diversity and equitability following the PETM extinction. In contrast, the middle Ypresian

Early Eocene deep-sea benthic foraminiferal faunas: Recovery from the Paleocene Eocene Thermal Maximum extinction in a greenhouse world.

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Gabriela J Arreguín-Rodríguez

Full Text Available The early Eocene greenhouse world was marked by multiple transient hyperthermal events. The most extreme was the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma, linked to the extinction of the globally recognised deep-sea benthic foraminiferal Velasco fauna, which led to the development of early Eocene assemblages. This turnover has been studied at high resolution, but faunal development into the later early Eocene is poorly documented. There is no widely accepted early Eocene equivalent of the Late Cretaceous-Paleocene Velasco fauna, mainly due to the use of different taxonomic concepts. We compiled Ypresian benthic foraminiferal data from 17 middle bathyal-lower abyssal ocean drilling sites in the Pacific, Atlantic and Indian Oceans, in order to characterise early Eocene deep-sea faunas by comparing assemblages across space, paleodepth and time. Nuttallides truempyi, Oridorsalis umbonatus, Bulimina trinitatensis, the Bulimina simplex group, the Anomalinoides spissiformis group, pleurostomellids, uniserial lagenids, stilostomellids and lenticulinids were ubiquitous during the early Eocene (lower-middle Ypresian. Aragonia aragonensis, the Globocassidulina subglobosa group, the Cibicidoides eocaenus group and polymorphinids became ubiquitous during the middle Ypresian. The most abundant early Ypresian taxa were tolerant to stressed or disturbed environments, either by opportunistic behavior (Quadrimorphina profunda, Tappanina selmensis, Siphogenerinoides brevispinosa and/or the ability to calcify in carbonate-corrosive waters (N. truempyi. Nuttallides truempyi, T. selmensis and other buliminids (Bolivinoides cf. decoratus group, Bulimina virginiana were markedly abundant during the middle Ypresian. Contrary to the long-lived, highly diverse and equitable Velasco fauna, common and abundant taxa reflect highly perturbed assemblages through the earliest Ypresian, with lower diversity and equitability following the PETM extinction. In contrast, the

Early Eocene deep-sea benthic foraminiferal faunas: Recovery from the Paleocene Eocene Thermal Maximum extinction in a greenhouse world.

Science.gov (United States)

Arreguín-Rodríguez, Gabriela J; Thomas, Ellen; D'haenens, Simon; Speijer, Robert P; Alegret, Laia

2018-01-01

The early Eocene greenhouse world was marked by multiple transient hyperthermal events. The most extreme was the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma), linked to the extinction of the globally recognised deep-sea benthic foraminiferal Velasco fauna, which led to the development of early Eocene assemblages. This turnover has been studied at high resolution, but faunal development into the later early Eocene is poorly documented. There is no widely accepted early Eocene equivalent of the Late Cretaceous-Paleocene Velasco fauna, mainly due to the use of different taxonomic concepts. We compiled Ypresian benthic foraminiferal data from 17 middle bathyal-lower abyssal ocean drilling sites in the Pacific, Atlantic and Indian Oceans, in order to characterise early Eocene deep-sea faunas by comparing assemblages across space, paleodepth and time. Nuttallides truempyi, Oridorsalis umbonatus, Bulimina trinitatensis, the Bulimina simplex group, the Anomalinoides spissiformis group, pleurostomellids, uniserial lagenids, stilostomellids and lenticulinids were ubiquitous during the early Eocene (lower-middle Ypresian). Aragonia aragonensis, the Globocassidulina subglobosa group, the Cibicidoides eocaenus group and polymorphinids became ubiquitous during the middle Ypresian. The most abundant early Ypresian taxa were tolerant to stressed or disturbed environments, either by opportunistic behavior (Quadrimorphina profunda, Tappanina selmensis, Siphogenerinoides brevispinosa) and/or the ability to calcify in carbonate-corrosive waters (N. truempyi). Nuttallides truempyi, T. selmensis and other buliminids (Bolivinoides cf. decoratus group, Bulimina virginiana) were markedly abundant during the middle Ypresian. Contrary to the long-lived, highly diverse and equitable Velasco fauna, common and abundant taxa reflect highly perturbed assemblages through the earliest Ypresian, with lower diversity and equitability following the PETM extinction. In contrast, the middle Ypresian

Cenozoic planktonic marine diatom diversity and correlation to climate change

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Lazarus, David; Barron, John; Renaudie, Johan; Diver, Patrick; Türke, Andreas

2014-01-01

Marine planktonic diatoms export carbon to the deep ocean, playing a key role in the global carbon cycle. Although commonly thought to have diversified over the Cenozoic as global oceans cooled, only two conflicting quantitative reconstructions exist, both from the Neptune deep-sea microfossil occurrences database. Total diversity shows Cenozoic increase but is sample size biased; conventional subsampling shows little net change. We calculate diversity from a separately compiled new diatom species range catalog, and recalculate Neptune subsampled-in-bin diversity using new methods to correct for increasing Cenozoic geographic endemism and decreasing Cenozoic evenness. We find coherent, substantial Cenozoic diversification in both datasets. Many living cold water species, including species important for export productivity, originate only in the latest Miocene or younger. We make a first quantitative comparison of diatom diversity to the global Cenozoic benthic ∂18O (climate) and carbon cycle records (∂13C, and 20-0 Ma pCO2). Warmer climates are strongly correlated with lower diatom diversity (raw: rho = .92, p2 were only moderately higher than today. Diversity is strongly correlated to both ∂13C and pCO2 over the last 15 my (for both: r>.9, detrended r>.6, all p<.001), but only weakly over the earlier Cenozoic, suggesting increasingly strong linkage of diatom and climate evolution in the Neogene. Our results suggest that many living marine planktonic diatom species may be at risk of extinction in future warm oceans, with an unknown but potentially substantial negative impact on the ocean biologic pump and oceanic carbon sequestration. We cannot however extrapolate our my-scale correlations with generic climate proxies to anthropogenic time-scales of warming without additional species-specific information on proximate ecologic controls.

Public aquaria as long-term enrichments for investigating planktonic Archaea

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Goldenstein, Nadine I.; Warren, Courtney E.; Lipp, Julius S.; Pagani, Mark; Hinrichs, Kai-Uwe

2016-04-01

The most abundant group of planktonic Archaea , the so-called Thaumarchaeota, represents 20% of all marine planktonic microorganisms (Karner et al., 2001) and their energy efficient performance of nitrification makes them key players in the global nitrogen- and carbon-cycle (Könneke et al., 2014). Furthermore, planktonic Archaea are considered to be the major producers of specific microbial membrane lipids that are extensively used as paleoproxies in marine climate research (Schouten et al., 2002). Therefore, assessing the parameters controlling the distribution of Archaea in the marine water column is crucial for studies of modern and past marine environments. Although diverse studies utilizing DNA- and biomarker-based approaches have constrained the turnover and distribution of marine Archaea, the environmental factors affecting their abundance and activity (e.g., Wuchter et al., 2006; Bale et al., 2013) are still poorly understood. Further, previous surveys, using enrichment cultivation and pure culture experiments, provided valuable information on adaptation of planktonic Archaea to changes of parameters affecting growth conditions, such as temperature, salinity and growth stage (Elling et al., 2014, 2015). Hence, we know that planktonic Archaea directly adapt their membranes to changing growth conditions, but also that environmental selection for individual phylogenetic groups of these organisms is also reflected in the membrane lipid pool. Extending these studies, this project further aims at constraining the environmental parameters controlling archaeal abundance in the marine environment. Public aquaria, which are comparable to perfectly monitored long-term enrichment cultures, are optimal sampling sites for this task. A comprehensive set of 120 water and substrate samples from fresh, marine and brackish systems exhibiting diverse conditions was selected from 15 public aquaria at the east and west coast of the USA. These samples were examined for their

Pemanfaatan Plankton sebagai Sumber Makanan Ikan Bandeng di Waduk Ir. H. Juanda, Jawa Barat

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Deden Ibnu Aqil

2016-03-01

Full Text Available Introducing of Milkfish (Chanos chanos was aimed to utilize natural food from plankton that were abundant in Ir. H. Juanda Reservoir, West Java. This research aimed to know plankton utilization by Milkfish in Ir. H. Juanda Reservoir, West Java. The research was conducted from February to July 2010 at 4 stations of sampling which representing the reservoir condition. The fishes collected based on the catch of fishermen. The sample was analyzed in physiology laboratory of Center Research for Limnology. The result of this research showed that the main food were plankton 43%, detritus 46%, and complement food were vegetation 11%. The domination food from the phytoplankton were Bacillariophyceae and zooplankton were Copepoda.

Planktonic growth and biofilm formation profiles in Candida haemulonii species complex.

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Ramos, Lívia S; Oliveira, Simone S C; Souto, Xênia M; Branquinha, Marta H; Santos, André L S

2017-10-01

Candida haemulonii species complex have emerged as multidrug-resistant yeasts able to cause fungemia worldwide. However, very little is known regarding their physiology and virulence factors. In this context, planktonic growth and biofilm formation of Brazilian clinical isolates of Candida haemulonii (n = 5), Candida duobushaemulonii (n = 4), and Candida haemulonii var. vulnera (n = 3) were reported. Overall, the fungal planktonic growth curves in Sabouraud dextrose broth reached the exponential phase in 48 h at 37°C. All the clinical isolates formed biofilm on polystyrene in a time-dependent event, as judged by the parameters evaluated: biomass (crystal violet staining), metabolic activity (XTT reduction), and extracellular matrix (safranin incorporation). No statistically significant differences were observed when the average measurements among the three Candida species were compared regarding both planktonic and biofilm lifestyles; however, typical isolate-specific differences were clearly noticed in fungal growth kinetics. © The Author 2017. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

GLOBEC NEP MOCNESS Plankton (MOC1) Data, 2000-2002

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National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) California Current Program MOCNESS Plankton (MOC1) Data The MOCNESS is based on the Tucker Trawl...

Benthic foraminiferal and isotopic patterns during the Early Eocene Climatic Optimum (Aktulagay section, Kazakhstan)

Science.gov (United States)

Deprez, Arne; Tesseur, Steven; Stassen, Peter; D'haenens, Simon; Steurbaut, Etienne; King, Christopher; Claeys, Philippe; Speijer, Robert P.

2015-04-01

The early Eocene is characterized by long-term global warming culminating in the Early Eocene Climatic Optimum (EECO). During this time interval, the Peri-Tethys was connected to the Arctic and Atlantic Oceans by north-south and east-west trending seaways. The Aktulagay section in Kazakhstan provides an expanded record of the middle Ypresian (NP11-13, ~54-50 Ma; King et al., 2013), including the EECO. The marl sequence features a series of sapropel beds, observed throughout the Peri-Tethys, indicative of basin-wide episodic hypoxic events. In order to unravel paleoenvironmental changes, we carried out quantitative faunal studies and stable isotopic (C, O) investigations on excellently preserved foraminiferal assemblages. The period from 54 to 52.5 Ma (NP11 to lower NP12; Alashen Formation) is characterized by a diverse assemblage of deep outer neritic (~200-250 m) benthic foraminifera, with common Pulsiphonina prima and Paralabamina lunata. The initially (54 Ma) well-ventilated oligo- to mesotrophic seafloor conditions gradually changed to more eutrophic and oxygen-limited. These conditions were more permanent in the sapropel-bearing unit at 52.5-52 Ma (middle NP12; Aktulagay B1 unit). This observation is based on the dominance of Anomalinoides acutus and Bulimina aksuatica and the lower diversity. Also the upward migration of endobenthic species, as suggested by rising δ13Cendobenthic, supports this interpretation. These low-oxygen conditions might have been caused by a transgression, flooding lowlands. Benthic foraminiferal assemblages dominated by Epistominella minuta at ~52-50 Ma (top NP12-NP13; Aktulagay B2 unit) suggest an oligotrophic environment, with transient pulses of phytodetritus. Dinoflagellate blooms and Acarinina isotope values at ~50.5 Ma indicate lower salinity (lower δ18O) and higher productivity (higher δ13C), possibly due to riverine input. Large river plumes, episodically reaching the area, in a monsoonal climate context, might explain this

First record of Lophodinium polylophum (Daday Lemmermann 1910 (Dinophyceae: Lophodiniaceae in Peru

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Iris Samanez

2015-04-01

Full Text Available Herein, the first record of Lophodinium polylophum from Peru is presented. This fresh water dinoflagellate was identified in plankton samples from the lagoon Picoplancha of Santuario Nacional Pampas del Heath (Madre de Dios and from a stream in the Puinahua River basin in Loreto.

Linking the planktonic and benthic habitat: genetic structure of the marine diatom Skeletonema marinoi.

Science.gov (United States)

Godhe, Anna; Härnström, Karolina

2010-10-01

Dormant life stages are important strategies for many aquatic organisms. The formation of resting stages will provide a refuge from unfavourable conditions in the water column, and their successive accumulation in the benthos will constitute a genetic reservoir for future planktonic populations. We have determined the genetic structure of a common bloom-forming diatom, Skeletonema marinoi, in the sediment and the plankton during spring, summer and autumn two subsequent years (2007-2009) in Gullmar Fjord on the Swedish west coast. Eight polymorphic microsatellite loci were used to assess the level of genetic differentiation and the respective gene diversity of the two different habitats. We also determined the degree of genetic differentiation between the seed banks inside the fjord and the open sea. The results indicate that Gullmar Fjord has one dominant endogenous population of S. marinoi, which is genetically differentiated from the open sea population. The fjord population is encountered in the plankton and in the sediment. Shifts from the dominant population can happen, and in our study, two genetically differentiated plankton populations, displaying reduced genetic diversity, occurred in September 2007 and 2008. Based on our results, we suggest that sill fjords maintain local long-lived and well-adapted protist populations, which continuously shift between the planktonic and benthic habitats. Intermittently, short-lived and mainly asexually reproducing populations can replace the dominant population in the water column, without influencing the genetic structure of the benthic seed bank. © 2010 Blackwell Publishing Ltd.

Marine plankton as an indicator of low-level radionuclide contamination in the Southern Ocean

International Nuclear Information System (INIS)

Marsh, K.V.; Buddemeier, R.W.

1984-07-01

We have initiated an investigation of the utility of marine plankton as bioconcentrating samplers of low-level marine radioactivity in the southern hemisphere. A literature review shows that both freshwater and marine plankton have trace element and radionuclide concentration factors (relative to water) of up to 10 4 . In the years 1956-1958, considerable work was done on the accumulation and distribution of a variety of fission and activation products produced by the nuclear tests in the Marshall Islands. Since then, studies have largely been confined to a few selected radionuclides, and by far most of this work has been done in the northern hemisphere. We participated in Operation Deepfreeze 1981, collecting 32 plankton samples from the U.S. Coast Guard Cutter Glacier on its Antarctic cruise, while Battelle Pacific Northwest Laboratories concurrently sampled air, water, rain and fallout. We were able to measure concentrations of the naturally occurring radionuclides 7 Be, 40 K and the U and th series, and we believe that we have detected low levels of 144 Ce and 95 Nb in seven samples ranging as far south as 68 0 . There is a definite association between the radionuclide content of plankton and air filters, suggesting that aerosol resuspension of marine radioactivity may be occurring. Biological identification of the plankton suggests a possible correlation between radionuclide concentration and foraminifera content of the samples. 38 references, 7 figures, 3 tables

Planktic foraminiferal responses to orbital scale oceanographic changes off the western Iberian margin over the last 900 kyr: Results from IODP site U1391

Science.gov (United States)

Singh, A. D.; Verma, K.; Jaiswal, S.; Alonso-Garcia, M.; Li, B.; Abrantes, F.

2015-12-01

This paper presents planktic foraminiferal assemblage records of the last 900 kyr from the SW Iberian margin (IODP Site U1391). The faunal records show the history of surface oceanographic changes on glacial/interglacial scales before and after the Mid-Brunhes Event (MBE), a period when a major shift in the climate pattern was recorded in other regions. Temporal variations in relative abundances of characteristic species/groups are used to infer changes in the latitudinal position of the polar/Arctic water (% Neogloboquadrina pachyderma sinistral and Turborotalita quinqueloba), influence of the transitional subpolar water mass (% N. pachyderma dextral), and subtropical water (% tropical/subtropical species/group). Past changes in the upwelling intensity and productivity pattern associated with seasonal trade wind strength are inferred from the abundance variations of Globigerina bulloides and G. bulloides + Globigerinita glutinata, respectively. Faunal data reveal the influence of cold water masses (polar/subpolar) at the examined site was more pronounced during glacial stages except for marine isotope stage (MIS) 14 and 16. The magnitude of the polar/subpolar water mass invading the study area was at maximum before the MBE during MIS 18, 20 and 22, resulting in a situation like the present day Arctic Front. Interglacial periods prior to the MBE were also relatively colder than those of the post-MBE. Our faunal based inferences are in agreement with the ice-rafted debris (IRD) concentration and N. pachyderma sinistral records of the subpolar North Atlantic sites. Based on faunal proxies, we recorded major and rapid changes in upwelling intensity and related productivity during glacial Terminations. Both the upwelling intensity and productivity significantly increased after the MBE, particularly during the interglacials MIS 7, 9 and 11. Our productivity record parallels the EPICA CH4 record suggesting teleconnections between trade winds induced productivity and the

Palaeoenvironmental changes across the Danian–Selandian boundary in the North Sea Basin

DEFF Research Database (Denmark)

Clemmensen, Anne; Thomsen, Erik

2005-01-01

cores from Storebælt in the eastern part of the North Sea Basin, we have reconstructed the palaeoenvironmental changes across the boundary. The benthic foraminiferal faunas belong to the “Midway-type fauna”. They are extremely rich and more than 260 taxa have been recognized. Q-mode cluster analysis......, the sea bottom conditions became colder and more acidic. This resulted in partial dissolution of the carbonates and the deposition shifted from marl to clay. Comparison with records from the Western Pyrenees, the Nile Basin and the eastern North America suggests that sea-level changes across the Danian......The Danian–Selandian boundary (not, vert, similar60 Ma) marks the cessation of 40 million years of carbonate deposition in the North Sea Basin and a shift to siliciclastic deposition. On the basis of variations in lithology, benthic and planktonic foraminifera and calcareous nannofossils in three...

A resource-based game theoretical approach for the paradox of the plankton

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Weini Huang

2016-08-01

Full Text Available The maintenance of species diversity is a central focus in ecology. It is not rare to observe more species than the number of limiting resources, especially in plankton communities. However, such high species diversity is hard to achieve in theory under the competitive exclusion principles, known as the plankton paradox. Previous studies often focus on the coexistence of predefined species and ignore the fact that species can evolve. We model multi-resource competitions using evolutionary games, where the number of species fluctuates under extinction and the appearance of new species. The interspecific and intraspecific competitions are captured by a dynamical payoff matrix, which has a size of the number of species. The competition strength (payoff entries is obtained from comparing the capability of species in consuming resources, which can change over time. This allows for the robust coexistence of a large number of species, providing a possible solution to the plankton paradox.

A resource-based game theoretical approach for the paradox of the plankton.

Science.gov (United States)

Huang, Weini; de Araujo Campos, Paulo Roberto; Moraes de Oliveira, Viviane; Fagundes Ferrreira, Fernando

2016-01-01

The maintenance of species diversity is a central focus in ecology. It is not rare to observe more species than the number of limiting resources, especially in plankton communities. However, such high species diversity is hard to achieve in theory under the competitive exclusion principles, known as the plankton paradox. Previous studies often focus on the coexistence of predefined species and ignore the fact that species can evolve. We model multi-resource competitions using evolutionary games, where the number of species fluctuates under extinction and the appearance of new species. The interspecific and intraspecific competitions are captured by a dynamical payoff matrix, which has a size of the number of species. The competition strength (payoff entries) is obtained from comparing the capability of species in consuming resources, which can change over time. This allows for the robust coexistence of a large number of species, providing a possible solution to the plankton paradox.

Can nearby eutrophic reservoirs sustain a differentiated biodiversity of planktonic microcrustaceans in a tropical semiarid basin?

Science.gov (United States)

Diniz, Leidiane P; Melo-Júnior, Mauro DE

2017-01-01

This paper aims to compare alpha and beta diversities of planktonic microcrustaceans from three reservoirs located nearby in a tropical semiarid basin. Our hypothesis was that alpha and beta diversities of the community are different, although the ecosystems are located close to each other. We carried out two sampling campaigns: dry and rainy seasons. The sampling of microcrustaceans and environmental variables (dissolved oxygen, chlorophyll a and nutrient) was performed at twelve stations and were distributed throughout the three zones (river, transition, and lacustrine), using a plankton net (45 µm). The reservoirs showed different uses and types of nitrogen predominance: Cachoeira (supply/nitrate), Borborema (sewage/ammonia) and Saco (aquaculture/ammonia). Seventeen species were recorded whose richness was assessed as particularly specific to each one of the studied reservoirs. Seasonally, both reservoirs with high anthropogenic alteration showed greater richness in the dry season. The three reservoirs located in a same basin showed different richness and composition, but the diversity did not differ between the zones of the reservoirs. Although communities are close to each other, their composition and richness were found to be distinct for each reservoir. This may be in response to the peculiar particularities, such as nitrogen sources and the different uses.

Can nearby eutrophic reservoirs sustain a differentiated biodiversity of planktonic microcrustaceans in a tropical semiarid basin?

Directory of Open Access Journals (Sweden)

LEIDIANE P. DINIZ

Full Text Available ABSTRACT This paper aims to compare alpha and beta diversities of planktonic microcrustaceans from three reservoirs located nearby in a tropical semiarid basin. Our hypothesis was that alpha and beta diversities of the community are different, although the ecosystems are located close to each other. We carried out two sampling campaigns: dry and rainy seasons. The sampling of microcrustaceans and environmental variables (dissolved oxygen, chlorophyll a and nutrient was performed at twelve stations and were distributed throughout the three zones (river, transition, and lacustrine, using a plankton net (45 µm. The reservoirs showed different uses and types of nitrogen predominance: Cachoeira (supply/nitrate, Borborema (sewage/ammonia and Saco (aquaculture/ammonia. Seventeen species were recorded whose richness was assessed as particularly specific to each one of the studied reservoirs. Seasonally, both reservoirs with high anthropogenic alteration showed greater richness in the dry season. The three reservoirs located in a same basin showed different richness and composition, but the diversity did not differ between the zones of the reservoirs. Although communities are close to each other, their composition and richness were found to be distinct for each reservoir. This may be in response to the peculiar particularities, such as nitrogen sources and the different uses.

Oceanic Anoxic Event 1b: insights and new data from the Poggio le Guaine section (Umbria-Marche Basin)

Science.gov (United States)

Sabatino, Nadia; Sprovieri, Mario; Coccioni, Rodolfo; Salvagio Manta, Daniela; Gardin, Silvia; Baudin, François

2015-04-01

The upper Aptian to lower Albian interval (~114-109 Ma) represents a crucial period during Earth's history, with a major evolution in the nature of mid-Cretaceous tectonics, sea level, climate, and marine plankton communities. Interestingly, it also includes multiple prominent black shale horizons that are the sedimentary expression of oceanic anoxic event (OAE) 1b. An high-resolution planktonic foraminiferal and calcareous nannofossil biostratigraphy in combination with an integrated study of multiple geochemical proxies (δ13Ccarb, δ13Corg, TOC, HI, CaCO3, trace elements/Al ratios) of the late Aptian-early Albian OAE 1b has been performed on the pelagic sedimentary sequence of Poggio le Guaine (Umbria-Marche Basin, central Italy). A comparison of the newly collected stable isotope carbon curve with the records from the Vocontian Basin (SE France), DSDP Site 545 and Hole 1049C provided a reliable and precise identification of the four main prominent black shale levels (113/Jacob, Kilian, Urbino/Paquier and Leenhardt) that definitively punctuate the OAE 1b. The studied record shows an increase in the marine organic carbon accumulation rate, in particular in the 113/Jacob and Urbino/Paquier levels. In the other black shales, TOC values are metals. The results suggest an increase in organic carbon burial rates during the OAE 1b due to the effect of enhanced surface productivity, as supported by a major increase in Ba/Al, and reduced bottom water ventilation. Noteworthy, the Kilian and Urbino/Paquier levels from the PLG section are characterized by the absence of correlative shifts in δ13Ccarb and δ13Corg. The increase in the δ13Corg, values in these levels is explained by an increase in the relative contribution of δ13C enriched marine planktonic archaeal biomass, while the concomitant negative excursions recorded in the δ13Ccarb could reflect a major contribution of isotopically light terrestrial carbonate ions from increased continental runoff during

Diatoms as Proxies for Abrupt Events in the Hudson River Estuary

Science.gov (United States)

Skorski, W.; Abbott, D. H.; Recasens, C.; Breger, D. L.

2014-12-01

The Hudson River estuary has been subject to many abrupt events throughout its history including hurricanes, droughts and pluvials. Hurricanes in particular are rare, discrete events that if fingerprinted can be used to develop better age models for Hudson River sediments. Proxies use observed physical characteristics or biological assemblages (e.g. diatom and foraminiferal assemblages) as tools to reconstruct past conditions prior to the modern instrumental record. Using a sediment core taken from the Hudson River (CDO2-29A), in New York City, drought and pluvial layers were selected based on Cs-137 dating while hurricane layers were determined from occurrences of tropical to subtropical foraminifera. Contrary to previous studies (Weaver, 1970, Weiss et al, 1978), more than sixty different diatom species have been identified using a scanning electron microscope (SEM). Cosmopolitan, hurricane and drought assemblages have begun to be identified after observing multiple layers (Table 1). Tropical foraminifera dominated by Globigerinoides ruber pink were also found in a hurricane layer that we infer was deposited during Hurricane Belle in 1976. More diatom abundance analyses and cataloged SEM pictures will provide further insight into these proxies. Table 1 Diatom Genera and Species Environment Clarification Cyclotella caspia Planktonic, marine-brackish Cosmopolitan Karayevia clevei Freshwater Cosmopolitan Melosira sp Planktonic, marine Cosmopolitan Thalassiosira sp Marine, brackish Cosmopolitan Staurosirella leptostauron Benthic, freshwater Cosmopolitan Actinoptychus senarius Planktonic or benthic, freshwater to brackish Hurricane and pluvial layers Amphora aff. sp Benthic, marine or freshwater Hurricane layers only Nitzschia sp Benthic, marine or freshwater Hurricane layers only Gomphonema sp Freshwater Hurricane layers only Surirella sp Marine-brackish Drought layer only Triceratium sp Marine Drought layer only Other Genera and species Environment Clarification

New Mediterranean Biodiversity Records (October, 2014

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S. KATSANEVAKIS

2014-11-01

Full Text Available The Collective Article ‘New Mediterranean Biodiversity Records’ of the Mediterranean Marine Science journal offers the means to publish biodiversity records in the Mediterranean Sea. The current article is divided in two parts, for records of alien and native species respectively. The new records of alien species include: the red alga Asparagopsis taxiformis (Crete and Lakonicos Gulf (Greece; the red alga Grateloupia turuturu (along the Israeli Mediterranean shore; the mantis shrimp Clorida albolitura (Gulf of Antalya, Turkey; the mud crab Dyspanopeus sayi (Mar Piccolo of Taranto, Ionian Sea; the blue crab Callinectes sapidus (Chios Island, Greece; the isopod Paracerceis sculpta (northern Aegean Sea, Greece; the sea urchin Diadema setosum (Gökova Bay, Turkey; the molluscs Smaragdia souverbiana, Murex forskoehlii, Fusinus verrucosus, Circenita callipyga, and Aplysia dactylomela (Syria; the cephalaspidean mollusc Haminoea cyanomarginata (Baia di Puolo, Massa Lubrense, Campania, southern Italy; the topmouth gudgeon Pseudorasbora parva (Civitavecchia, Tyrrhenian Sea; the fangtooth moray Enchelycore anatine (Plemmirio marine reserve, Sicily; the silver-cheeked toadfish Lagocephalus sceleratus (Saros Bay, Turkey; and Ibiza channel, Spain; the Indo-Pacific ascidian Herdmania momusin Kastelorizo Island (Greece; and the foraminiferal Clavulina multicam erata (Saronikos Gulf, Greece. The record of L. sceleratus in Spain consists the deepest (350-400m depth record of the species in the Mediterranean Sea. The new records of native species include: first record of the ctenophore Cestum veneris in Turkish marine waters; the presence of Holothuria tubulosa and Holothuria polii in the Bay of Igoumenitsa (Greece; the first recorded sighting of the bull ray Pteromylaeus bovinus in Maltese waters; and a new record of the fish Lobotes surinamensis from Maliakos Gulf.

Seasonal patterns in plankton communities in a pluriannual time series at a coastal Mediterranean site (Gulf of Naples: an attempt to discern recurrences and trends

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M. Ribera d'Alcalà

2004-04-01

Full Text Available The annual cycle of plankton was studied over 14 years from 1984 to 2000 at a coastal station in the Gulf of Naples, with the aim of assessing seasonal patterns and interannual trends. Phytoplankton biomass started increasing over the water column in February-early March, and generally achieved peak values in the upper layers in late spring. Another peak was often recorded in autumn. Diatoms and phytoflagellates dominated for the largest part of the year. Ciliates showed their main peaks in phase with phytoplankton and were mainly represented by small (< 30 mm naked choreotrichs. Mesozooplankton increased in March-April, reaching maximum concentrations in summer. Copepods were always the most abundant group, followed by cladocerans in summer. At the interannual scale, a high variability and a decreasing trend were recorded over the sampling period for autotrophic biomass. Mesozooplankton biomass showed a less marked interannual variability. From 1995 onwards, phytoplankton populations increased in cell number but decreased in cell size, with intense blooms of small diatoms and undetermined coccoid species frequently observed in recent years. In spite of those interannual variations, the different phases of the annual cycle and the occurrence of several plankton species were remarkably regular.

Massive consumption of gelatinous plankton by Mediterranean apex predators.

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Luis Cardona

Full Text Available Stable isotopes of carbon and nitrogen were used to test the hypothesis that stomach content analysis has systematically overlooked the consumption of gelatinous zooplankton by pelagic mesopredators and apex predators. The results strongly supported a major role of gelatinous plankton in the diet of bluefin tuna (Thunnus thynnus, little tunny (Euthynnus alletteratus, spearfish (Tetrapturus belone and swordfish (Xiphias gladius. Loggerhead sea turtles (Caretta caretta in the oceanic stage and ocean sunfish (Mola mola also primarily relied on gelatinous zooplankton. In contrast, stable isotope ratios ruled out any relevant consumption of gelatinous plankton by bluefish (Pomatomus saltatrix, blue shark (Prionace glauca, leerfish (Lichia amia, bonito (Sarda sarda, striped dolphin (Stenella caerueloalba and loggerhead sea turtles (Caretta caretta in the neritic stage, all of which primarily relied on fish and squid. Fin whales (Balaenoptera physalus were confirmed as crustacean consumers. The ratios of stable isotopes in albacore (Thunnus alalunga, amberjack (Seriola dumerili, blue butterfish (Stromaeus fiatola, bullet tuna (Auxis rochei, dolphinfish (Coryphaena hyppurus, horse mackerel (Trachurus trachurus, mackerel (Scomber scombrus and pompano (Trachinotus ovatus were consistent with mixed diets revealed by stomach content analysis, including nekton and crustaceans, but the consumption of gelatinous plankton could not be ruled out completely. In conclusion, the jellyvorous guild in the Mediterranean integrates two specialists (ocean sunfish and loggerhead sea turtles in the oceanic stage and several opportunists (bluefin tuna, little tunny, spearfish, swordfish and, perhaps, blue butterfish, most of them with shrinking populations due to overfishing.

Estimating planktonic diversity through spatial dominance patterns in a model ocean.

Science.gov (United States)

Soccodato, Alice; d'Ovidio, Francesco; Lévy, Marina; Jahn, Oliver; Follows, Michael J; De Monte, Silvia

2016-10-01

In the open ocean, the observation and quantification of biodiversity patterns is challenging. Marine ecosystems are indeed largely composed by microbial planktonic communities whose niches are affected by highly dynamical physico-chemical conditions, and whose observation requires advanced methods for morphological and molecular classification. Optical remote sensing offers an appealing complement to these in-situ techniques. Global-scale coverage at high spatiotemporal resolution is however achieved at the cost of restrained information on the local assemblage. Here, we use a coupled physical and ecological model ocean simulation to explore one possible metrics for comparing measures performed on such different scales. We show that a large part of the local diversity of the virtual plankton ecosystem - corresponding to what accessible by genomic methods - can be inferred from crude, but spatially extended, information - as conveyed by remote sensing. Shannon diversity of the local community is indeed highly correlated to a 'seascape' index, which quantifies the surrounding spatial heterogeneity of the most abundant functional group. The error implied in drastically reducing the resolution of the plankton community is shown to be smaller in frontal regions as well as in regions of intermediate turbulent energy. On the spatial scale of hundreds of kms, patterns of virtual plankton diversity are thus largely sustained by mixing communities that occupy adjacent niches. We provide a proof of principle that in the open ocean information on spatial variability of communities can compensate for limited local knowledge, suggesting the possibility of integrating in-situ and satellite observations to monitor biodiversity distribution at the global scale. Copyright © 2016 Elsevier B.V. All rights reserved.

Plankton community dynamics in a subtropical lagoonal system and related factors

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LETÍCIA DONADEL

2016-03-01

Full Text Available ABSTRACT Changes of the plankton community in a shallow, subtropical lagoonal system and its relation to environmental conditions were investigated during an annual cycle to provide information on its spatial and seasonal variation pattern. The study carried out at four sites (three in the Peixe lagoon and one in the Ruivo lagoon, which are located in the Lagoa do Peixe National Park, southern Brazil. The system has a temporary connection to the Atlantic Ocean by a narrow channel. The phytoplankton density was higher in the Peixe lagoon whereas the specific richness was higher in the Ruivo lagoon which is also a site with the lower salinity. The phytoplankton biomass near the channel showed seasonal variation with the highest value in fall and lowest in winter. Zooplankton richness was inversely correlated with salinity, and had the highest values in the Ruivo lagoon. Ordination analysis indicated seasonal and spatial patterns in plankton community in this lagoonal system, related to variation in salinity. In addition, the wind action and precipitation were important factors on the spatial and seasonal salinity changes in the lagoon with direct influence on the plankton community dynamics.

Computer vision for continuous plankton monitoring

OpenAIRE

Damian Janusz Matuszewski

2014-01-01

Plankton microorganisms constitute the base of the marine food web and play a great role in global atmospheric carbon dioxide drawdown. Moreover, being very sensitive to any environmental changes they allow noticing (and potentially counteracting) them faster than with any other means. As such they not only influence the fishery industry but are also frequently used to analyze changes in exploited coastal areas and the influence of these interferences on local environment and climate. As a co...

Study on kinetics of glucose uptake by some species of plankton

Science.gov (United States)

Li, Wenquan; Wang, Xian; Zhang, Yaohua

1993-03-01

The rates of glucose uptake by some species of plankton were determined by3H-glucose tracer method. Experimental results indicated that the observed glucose uptake at natural seawater concentrations by Platymonas subcordiformis and Brachionus plicatilis was principally a metabolic process fitted with the Michaelis-Menten equation in the range of adaptive temperatures. Heterotrophic uptake by Platymonas subcordiformis was mainly dependent on diffusion at high glucose levels. The uptake by Brachionus plicatilis showed active transport even at high glucose levels, indicating its high heterotrophic activity. The uptake rate by Artemia salina was lower, and its V m/K ratio was lower than those of the other two species of plankton.

Development of a real-time PCR assay for detection of planktonic red king crab (Paralithodes camtschaticus (Tilesius 1815)) larvae

Science.gov (United States)

Jensen, Pamela C.; Purcell, Maureen K.; Morado, J. Frank; Eckert, Ginny L.

2012-01-01

The Alaskan red king crab (Paralithodes camtschaticus) fishery was once one of the most economically important single-species fisheries in the world, but is currently depressed. This fishery would benefit from improved stock assessment capabilities. Larval crab distribution is patchy temporally and spatially, requiring extensive sampling efforts to locate and track larval dispersal. Large-scale plankton surveys are generally cost prohibitive because of the effort required for collection and the time and taxonomic expertise required to sort samples to identify plankton individually via light microscopy. Here, we report the development of primers and a dual-labeled probe for use in a DNA-based real-time polymerase chain reaction assay targeting the red king crab, mitochondrial gene cytochrome oxidase I for the detection of red king crab larvae DNA in plankton samples. The assay allows identification of plankton samples containing crab larvae DNA and provides an estimate of DNA copy number present in a sample without sorting the plankton sample visually. The assay was tested on DNA extracted from whole red king crab larvae and plankton samples seeded with whole larvae, and it detected DNA copies equivalent to 1/10,000th of a larva and 1 crab larva/5mL sieved plankton, respectively. The real-time polymerase chain reaction assay can be used to screen plankton samples for larvae in a fraction of the time required for traditional microscopial methods, which offers advantages for stock assessment methodologies for red king crab as well as a rapid and reliable method to assess abundance of red king crab larvae as needed to improve the understanding of life history and population processes, including larval population dynamics.

Antimicrobial Resistance Profile of Planktonic and Biofilm Cells of Staphylococcus aureus and Coagulase-Negative Staphylococci

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Adilson de Oliveira

2016-09-01

Full Text Available The objective of the present study was to determine the antimicrobial resistance profile of planktonic and biofilm cells of Staphylococcus aureus and coagulase-negative staphylococci (CoNS. Two hundred Staphylococcus spp. strains were studied, including 50 S. aureus and 150 CoNS strains (50 S. epidermidis, 20 S. haemolyticus, 20 S. warneri, 20 S. hominis, 20 S. lugdunensis, and 20 S. saprophyticus. Biofilm formation was investigated by adherence to polystyrene plates. Positive strains were submitted to the broth microdilution method to determine the minimum inhibitory concentration (MIC for planktonic and biofilm cells and the minimal bactericidal concentration for biofilm cells (MBCB. Forty-nine Staphylococcus spp. strains (14 S. aureus, 13 S. epidermidis, 13 S. saprophyticus, 3 S. haemolyticus, 1 S. hominis, 3 S. warneri, and 2 S. lugdunensis were biofilm producers. These isolates were evaluated regarding their resistance profile. Determination of planktonic cell MIC identified three (21.4% S. aureus strains that were resistant to oxacillin and six (42.8% that were resistant to erythromycin. Among the CoNS, 31 (88.6% strains were resistant to oxacillin, 14 (40% to erythromycin, 18 (51.4% to gentamicin, and 8 (22.8% to sulfamethoxazole/trimethoprim. None of the planktonic isolates were resistant to vancomycin or linezolid. MICs were 2-, 4-, 8-, and up to 16-fold higher for biofilm cells than for planktonic cells. This observation was more common for vancomycin and erythromycin. The MBCB ranged from 8 to >256 µg/mL for oxacillin, 128 to >128 µg/mL for vancomycin, 256 to >256 µg/mL for erythromycin and gentamicin, >64 µg/mL for linezolid, and 32/608 to >32/608 µg/mL for sulfamethoxazole/trimethoprim. The results showed considerably higher MICs for S. aureus and CoNS biofilm cells compared to planktonic cells. Analysis of MBCM confirmed that even high concentrations of vancomycin were unable to eliminate the biofilms of S. aureus and Co

Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition.

Science.gov (United States)

Alberti, Adriana; Poulain, Julie; Engelen, Stefan; Labadie, Karine; Romac, Sarah; Ferrera, Isabel; Albini, Guillaume; Aury, Jean-Marc; Belser, Caroline; Bertrand, Alexis; Cruaud, Corinne; Da Silva, Corinne; Dossat, Carole; Gavory, Frédérick; Gas, Shahinaz; Guy, Julie; Haquelle, Maud; Jacoby, E'krame; Jaillon, Olivier; Lemainque, Arnaud; Pelletier, Eric; Samson, Gaëlle; Wessner, Mark; Acinas, Silvia G; Royo-Llonch, Marta; Cornejo-Castillo, Francisco M; Logares, Ramiro; Fernández-Gómez, Beatriz; Bowler, Chris; Cochrane, Guy; Amid, Clara; Hoopen, Petra Ten; De Vargas, Colomban; Grimsley, Nigel; Desgranges, Elodie; Kandels-Lewis, Stefanie; Ogata, Hiroyuki; Poulton, Nicole; Sieracki, Michael E; Stepanauskas, Ramunas; Sullivan, Matthew B; Brum, Jennifer R; Duhaime, Melissa B; Poulos, Bonnie T; Hurwitz, Bonnie L; Pesant, Stéphane; Karsenti, Eric; Wincker, Patrick

2017-08-01

A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009-2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world's planktonic ecosystems.

A 3000 yr paleostorm record from St. Catherines Island, Georgia

Science.gov (United States)

Braun, Erick; Meyer, Brian; Deocampo, Daniel; Kiage, Lawrence M.

2017-09-01

Tropical cyclones (hurricanes in the northern hemisphere) are amongst the most devastating of the world's natural disasters and cause billions of dollars in damage every year. Data on the likelihood of a coastal site being struck by a major hurricane strike can potentially aid in planning and mitigation efforts that could save money and lives. However, forecasting requires data that are currently insufficient for the Georgia Bight. This study provides information to enhance the paleohurricane record by analysis of a 467 cm thick vibracore raised from St. Catherines Island, GA. Sediment geochemistry and foraminiferal assemblages indicate deposits attributable to seven paleohurricane events, five of which were likely major hurricanes when they made landfall on St. Catherines. Magnitudes were estimated by comparison to the overwash deposit left by ;The Sea Islands hurricane of 1893;, a major hurricane recorded by the recent sediment of St. Catherines Island. The St. Catherines record also shows a change in the activity levels on the Georgia coast with two distinct activity regimes over the past 3000 years.

Plankton composition and biomass development

DEFF Research Database (Denmark)

Jakobsen, H.H.; Jepsen, P.M.; Blanda, E.

2016-01-01

Plankton food web dynamics were studied during a complete production season in a semi-intensive land-based facility for rearing of turbot (Scophthalmus maximus) larvae. The production season was divided into three production cycles of 3–5 weeks. Phytoplankton biomass (using chlorophyll a as biomass...... proxy) peaked in each production cycle. However, the maximum biomass decreased from spring (18 μg chlorophyll a L−1) to fall (ca. 7 μg chlorophyll a L−1), simultaneous with a decline in the concentration of dissolved nitrogen in the inoculating water. During the three production cycles, we observed...

Hydromechanical signals in the plankton

DEFF Research Database (Denmark)

Visser, Andre

2001-01-01

The distance at which plankters can detect and thus interact with each other depends on their sensitivity, size, and motion, as well as the hydrodynamic characteristics of their behaviour. Through a simple consideration of the distribution of forces exerted on the ambient fluid by different...... proportional to a(3)Ur(-3). Within this context, observed planktonic interactions, particularly for copepods, were analysed and showed reasonably good support for the theory. The remote detection of inert particles by feeding-current-generating and free-swimming copepods was found to be feasible for known...... swimming ciliates under turbulent conditions showed good agreement with previously reported observations....

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

Validation and application of fossil DNA as a recorder of past marine ecosystems and environmental conditions

NARCIS (Netherlands)

Boere, A.C.

2010-01-01

The majority of planktonic species, including those that are informative in the reconstructions of past marine environmental conditions, do not produce diagnostic features (e.g., cysts, spores, or lipid biomarkers) and would therefore escape identification from the fossil record using traditional

Planktonic Biodiversity of Bhoj Wetland, Bhopal, India | Neelam ...

African Journals Online (AJOL)

Biodiversity found on Earth today consists of many millions of distinct biological species, which is the product of nearly 3.5 billion years of evolution. This article deals with planktonic distribution of Bhoj Wetland, Bhopal, India . Bhoj Wetland comprises of two lakes i.e. Upper and Lower lakes of Bhopal. The Upper lake is ...

Changes in Microbial Plankton Assemblages Induced by Mesoscale Oceanographic Features in the Northern Gulf of Mexico.

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Alicia K Williams

Full Text Available Mesoscale circulation generated by the Loop Current in the Northern Gulf of Mexico (NGOM delivers growth-limiting nutrients to the microbial plankton of the euphotic zone. Consequences of physicochemically driven community shifts on higher order consumers and subsequent impacts on the biological carbon pump remain poorly understood. This study evaluates microbial plankton <10 μm abundance and community structure across both cyclonic and anti-cyclonic circulation features in the NGOM using flow cytometry (SYBR Green I and autofluorescence parameters. Non-parametric multivariate hierarchical cluster analyses indicated that significant spatial variability in community structure exists such that stations that clustered together were defined as having a specific 'microbial signature' (i.e. statistically homogeneous community structure profiles based on relative abundance of microbial groups. Salinity and a combination of sea surface height anomaly and sea surface temperature were determined by distance based linear modeling to be abiotic predictor variables significantly correlated to changes in microbial signatures. Correlations between increased microbial abundance and availability of nitrogen suggest nitrogen-limitation of microbial plankton in this open ocean area. Regions of combined coastal water entrainment and mesoscale convergence corresponded to increased heterotrophic prokaryote abundance relative to autotrophic plankton. The results provide an initial assessment of how mesoscale circulation potentially influences microbial plankton abundance and community structure in the NGOM.

Identification of pectenotoxins in plankton, filter feeders, and isolated cells of a Dinophysis acuminata with an atypical toxin profile, from Chile.

Science.gov (United States)

Blanco, Juan; Alvarez, Gonzalo; Uribe, Eduardo

2007-04-01

A bloom of Dinophysis acuminata produced, in autumn of 2005, a closure of the scallop harvesting in Bahía Inglesa, in the Chilean III region. Isolated cells of this Dinophysis species were shown to contain 180 pg cell(-1) of pectenotoxin 2 but neither okadaic acid nor any of its analogs or derivatives (at least at a detectable level). Examination of plankton and filter-feeder samples covering an area of ca. 350 km, from the location where the toxicity was recorded to Bahía Tongoy, showed that the unique toxin profile found in the first bloom was widespread over that part of Chile and persisted for months. The analysis were carried out by HPLC-ESI-MS using positive ionization mode, with a detection limit below 2 ng of OA mL(-1) of methanolic extract. This is the first report of the presence of pectenotoxins in the plankton of the Pacific coast of America and in the studied filter feeders. This is also the first report of a Dinophysis species containing pectenotoxins and not any toxin of the okadaic acid group.

Limits to gene flow in a cosmopolitan marine planktonic diatom.

Science.gov (United States)

Casteleyn, Griet; Leliaert, Frederik; Backeljau, Thierry; Debeer, Ann-Eline; Kotaki, Yuichi; Rhodes, Lesley; Lundholm, Nina; Sabbe, Koen; Vyverman, Wim

2010-07-20

The role of geographic isolation in marine microbial speciation is hotly debated because of the high dispersal potential and large population sizes of planktonic microorganisms and the apparent lack of strong dispersal barriers in the open sea. Here, we show that gene flow between distant populations of the globally distributed, bloom-forming diatom species Pseudo-nitzschia pungens (clade I) is limited and follows a strong isolation by distance pattern. Furthermore, phylogenetic analysis implies that under appropriate geographic and environmental circumstances, like the pronounced climatic changes in the Pleistocene, population structuring may lead to speciation and hence may play an important role in diversification of marine planktonic microorganisms. A better understanding of the factors that control population structuring is thus essential to reveal the role of allopatric speciation in marine microorganisms.

Global marine plankton functional type biomass distributions : Phaeocystis spp

NARCIS (Netherlands)

Vogt, M.; O'Brien, C.; Peloquin, J.; Schoemann, V.; Breton, E.; Estrada, M.; Gibson, J.; Karentz, D.; van Leeuwe, M. A.; Stefels, J.; Widdicombe, C.; Peperzak, L.

2012-01-01

The planktonic haptophyte Phaeocystis has been suggested to play a fundamental role in the global biogeochemical cycling of carbon and sulphur, but little is known about its global biomass distribution. We have collected global microscopy data of the genus Phaeocystis and converted abundance data to

Competition between autotrophic and heterotrophic microbial plankton for inorganic nutrients induced by variability in estuarine biophysicochemical conditions

Science.gov (United States)

Williams, A.; Quigg, A.

2016-02-01

Competition for inorganic nutrients between autotrophic and heterotrophic fractions of microbial plankton (0.2-20μm) was investigated at two stations in a sub-tropical estuary, Galveston Bay, Texas. Competition potential between these groups is enhanced because individuals are similar in size, reducing variability among their nutrient uptake efficiencies. Further, in estuaries, allochthonous supplements to autochthonous carbon may satisfy heterotrophic requirements, allowing alternative factors to limit abundance. The relative abundance of autotrophs and heterotrophs stained with SYBR Green I and enumerated on a Beckman Coulter Gallios flow cytometer were evaluated monthly during a year-long study. Shifts in the relative in situ abundance were significantly related to temperature, dissolved inorganic nitrogen (DIN), phosphorous (Pi), and total organic carbon (TOC) concentrations revealing opposing gradients of limitation by different abiotic factors. In corresponding in vitro nutrient enrichment bioassays the relative contribution of autotrophic or heterotrophic microbial plankton to significant enrichment responses varied. Only during macro- (>20μm) phytoplankton blooms do autotrophic microbial plankton respond to nutrient enrichment. Contrastingly, the heterotrophic microbial plankton responded to nutrient enrichment primarily when temperature limitation was alleviated. Therefore, the potential for autotrophic and heterotrophic microbial plankton competition for limiting nutrients is highest when autotrophic microbial plankton are also competing with larger phytoplankton during bloom events. Based on this evidence, we hypothesize that the autotrophic microbial fraction has a competitive advantage over the heterotrophs for inorganic nutrients in Galveston Bay. The observed microbial competition during estuarine phytoplankton blooms may have important consequences on biogeochemical processes including carbon and nutrient cycling.

Toxicity of waters from the Rochester Embayment Area of Concern to the plankton species Pseudokirchneriella subcapitata and Ceriodaphnia dubia

Science.gov (United States)

Baldigo, Barry P.; Duffy, Brian T.; Smith, Alexander J.; George, Scott D.

2016-01-01

The lower Genesee River and Rochester Embayment of Lake Ontario are a designated Area of Concern (AOC) under the binational Great Lakes Water Quality Agreement. The “degradation of phytoplankton and zooplankton populations” or plankton Beneficial Use Impairment (BUI) was classified as unknown and in need of further assessment in this AOC because water quality data suggested plankton communities could be effected and community data were either unavailable or indicated impacts. The plankton BUI may now be obsolete because local contaminant sources have been largely eliminated. The present study was conducted between July 2013 and August 2014 to assess the BUI-removal criteria: “AOC plankton bioassays confirm that toxicity in ambient waters (i.e., no growth inhibition) is not significantly higher than comparable non-AOC controls”. Acute and chronic toxicity of waters from 13 sites were quantified seasonally using standardized bioassays with the green alga Pseudokirchneriella subcapitata and water flea Ceriodaphnia dubia to test the hypothesis that toxicity of waters from AOC sites was not higher than that of waters from comparable non-AOC reference sites. Survival and reproduction of C. dubia did not differ significantly between site types, systems, or months. The growth of P. subcapitata did not differ between site types, but differed among systems and months. All results indicate that waters from AOC sites were no more toxic to both plankton species than waters from reference sites. Assuming test species represent natural plankton assemblages, water quality should not negatively affect survival and growth of resident plankton populations in the Rochester Embayment AOC.

Persistent organic pollutants in Mediterranean seawater and processes affecting their accumulation in plankton.

Science.gov (United States)

Berrojalbiz, Naiara; Dachs, Jordi; Del Vento, Sabino; Ojeda, María José; Valle, María Carmen; Castro-Jiménez, Javier; Mariani, Giulio; Wollgast, Jan; Hanke, Georg

2011-05-15

The Mediterranean and Black Seas are unique marine environments subject to important anthropogenic pressures due to riverine and atmospheric inputs of organic pollutants. Here, we report the results obtained during two east-west sampling cruises in June 2006 and May 2007 from Barcelona to Istanbul and Alexandria, respectively, where water and plankton samples were collected simultaneously. Both matrixes were analyzed for hexaclorochyclohexanes (HCHs), hexachlorobenzene (HCB), and 41 polychlorinated biphenyl (PCB) congeners. The comparison of the measured HCB and HCHs concentrations with previously reported dissolved phase concentrations suggests a temporal decline in their concentrations since the 1990s. On the contrary, PCB seawater concentrations did not exhibit such a decline, but show a significant spatial variability in dissolved concentrations with lower levels in the open Western and South Eastern Mediterranean, and higher concentrations in the Black, Marmara, and Aegean Seas and Sicilian Strait. PCB and OCPs (organochlorine pesticides) concentrations in plankton were higher at lower plankton biomass, but the intensity of this trend depended on the compound hydrophobicity (K(OW)). For the more persistent PCBs and HCB, the observed dependence of POP concentrations in plankton versus biomass can be explained by interactions between air-water exchange, particle settling, and/or bioaccumulation processes, whereas degradation processes occurring in the photic zone drive the trends shown by the more labile HCHs. The results presented here provide clear evidence of the important physical and biogeochemical controls on POP occurrence in the marine environment.

Plankton motility patterns and encounter rates

DEFF Research Database (Denmark)

Visser, Andre; Kiørboe, Thomas

2006-01-01

measure of run length to reaction distance determines whether the underlying encounter is ballistic or diffusive. Since ballistic interactions are intrinsically more efficient than diffusive, we predict that organisms will display motility with long correlation run lengths compared to their reaction...... distances to their prey, but short compared to the reaction distances of their predators. We show motility data for planktonic organisms ranging from bacteria to copepods that support this prediction. We also present simple ballistic and diffusive motility models for estimating encounter rates, which lead...

Mercury methylation rates of biofilm and plankton microorganisms from a hydroelectric reservoir in French Guiana.

Science.gov (United States)

Huguet, L; Castelle, S; Schäfer, J; Blanc, G; Maury-Brachet, R; Reynouard, C; Jorand, F

2010-02-15

The Petit-Saut ecosystem is a hydroelectric reservoir covering 365km(2) of flooded tropical forest. This reservoir and the Sinnamary Estuary downstream of the dam are subject to significant mercury methylation. The mercury methylation potential of plankton and biofilm microorganisms/components from different depths in the anoxic reservoir water column and from two different sites along the estuary was assessed. For this, reservoir water and samples of epiphytic biofilms from the trunk of a submerged tree in the anoxic water column and from submerged branches in the estuary were batch-incubated from 1h to 3 months with a nominal 1000ng/L spike of Hg(II) chloride enriched in (199)Hg. Methylation rates were determined for different reservoir and estuarine communities under natural nutrient (reservoir water, estuary freshwater) and artificial nutrient (culture medium) conditions. Methylation rates in reservoir water incubations were the highest with plankton microorganisms sampled at -9.5m depth (0.5%/d) without addition of biofilm components. Mercury methylation rates of incubated biofilm components were strongly enhanced by nutrient addition. The results suggested that plankton microorganisms strongly contribute to the total Hg methylation in the Petit-Saut reservoir and in the Sinnamary Estuary. Moreover, specific methylation efficiencies (%Me(199)Hg(net)/cell) suggested that plankton microorganisms could be more efficient methylating actors than biofilm consortia and that their methylation efficiency may be reduced in the presence of biofilm components. Extrapolation to the reservoir scale of the experimentally determined preliminary methylation efficiencies suggested that plankton microorganisms in the anoxic water column could produce up to 27mol MeHg/year. Taking into account that (i) demethylation probably occurs in the reservoir and (ii) that the presence of biofilm components may limit the methylation efficiency of plankton microorganisms, this result is

Plankton networks driving carbon export in the oligotrophic ocean

Science.gov (United States)

Larhlimi, Abdelhalim; Roux, Simon; Darzi, Youssef; Audic, Stephane; Berline, Léo; Brum, Jennifer; Coelho, Luis Pedro; Espinoza, Julio Cesar Ignacio; Malviya, Shruti; Sunagawa, Shinichi; Dimier, Céline; Kandels-Lewis, Stefanie; Picheral, Marc; Poulain, Julie; Searson, Sarah; Stemmann, Lars; Not, Fabrice; Hingamp, Pascal; Speich, Sabrina; Follows, Mick; Karp-Boss, Lee; Boss, Emmanuel; Ogata, Hiroyuki; Pesant, Stephane; Weissenbach, Jean; Wincker, Patrick; Acinas, Silvia G.; Bork, Peer; de Vargas, Colomban; Iudicone, Daniele; Sullivan, Matthew B.; Raes, Jeroen; Karsenti, Eric; Bowler, Chris; Gorsky, Gabriel

2015-01-01

The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterised. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria, alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of just a few bacterial and viral genes can predict most of the variability in carbon export in these regions. PMID:26863193

Plankton networks driving carbon export in the oligotrophic ocean

Science.gov (United States)

2016-04-01

The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterized. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria and alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of a few bacterial and viral genes can predict a significant fraction of the variability in carbon export in these regions.

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...

Planktonic food webs revisited: Reanalysis of results from the linear inverse approach

Science.gov (United States)

Hlaili, Asma Sakka; Niquil, Nathalie; Legendre, Louis

2014-01-01

Identification of the trophic pathway that dominates a given planktonic assemblage is generally based on the distribution of biomasses among food-web compartments, or better, the flows of materials or energy among compartments. These flows are obtained by field observations and a posteriori analyses, including the linear inverse approach. In the present study, we re-analysed carbon flows obtained by inverse analysis at 32 stations in the global ocean and one large lake. Our results do not support two "classical" views of plankton ecology, i.e. that the herbivorous food web is dominated by mesozooplankton grazing on large phytoplankton, and the microbial food web is based on microzooplankton significantly consuming bacteria; our results suggest instead that phytoplankton are generally grazed by microzooplankton, of which they are the main food source. Furthermore, we identified the "phyto-microbial food web", where microzooplankton largely feed on phytoplankton, in addition to the already known "poly-microbial food web", where microzooplankton consume more or less equally various types of food. These unexpected results led to a (re)definition of the conceptual models corresponding to the four trophic pathways we found to exist in plankton, i.e. the herbivorous, multivorous, and two types of microbial food web. We illustrated the conceptual trophic pathways using carbon flows that were actually observed at representative stations. The latter can be calibrated to correspond to any field situation. Our study also provides researchers and managers with operational criteria for identifying the dominant trophic pathway in a planktonic assemblage, these criteria being based on the values of two carbon ratios that could be calculated from flow values that are relatively easy to estimate in the field.

AXIALLY ORIENTED SECTIONS OF NUMMULITIDS: A TOOL TO INTERPRET LARGER BENTHIC FORAMINIFERAL DEPOSITS.

Science.gov (United States)

Hohenegger, Johann; Briguglio, Antonino

2012-04-01

The "critical shear velocity" and "settling velocity" of foraminiferal shells are important parameters for determining hydrodynamic conditions during deposition of Nummulites banks. These can be estimated by determining the size, shape, and density of nummulitid shells examined in axial sections cut perpendicular to the bedding plane. Shell size and shape can be determined directly from the shell diameter and thickness, but density must be calculated indirectly from the thin section. Calculations using the half-tori method approximate shell densities by equalizing the chamber volume of each half whorl, based on the half whorl's lumen area and its center of gravity. Results from this method yield the same lumen volumes produced empirically by micro-computed tomography. The derived hydrodynamic parameters help estimate the minimum flow velocities needed to entrain nummulitid tests and provide a potential tool to account for the nature of their accumulations.

Spatial Distribution of Viruses Associated with Planktonic and Attached Microbial Communities in Hydrothermal Environments

Science.gov (United States)

Nunoura, Takuro; Kazama, Hiromi; Noguchi, Takuroh; Inoue, Kazuhiro; Akashi, Hironori; Yamanaka, Toshiro; Toki, Tomohiro; Yamamoto, Masahiro; Furushima, Yasuo; Ueno, Yuichiro; Yamamoto, Hiroyuki; Takai, Ken

2012-01-01

Viruses play important roles in marine surface ecosystems, but little is known about viral ecology and virus-mediated processes in deep-sea hydrothermal microbial communities. In this study, we examined virus-like particle (VLP) abundances in planktonic and attached microbial communities, which occur in physical and chemical gradients in both deep and shallow submarine hydrothermal environments (mixing waters between hydrothermal fluids and ambient seawater and dense microbial communities attached to chimney surface areas or macrofaunal bodies and colonies). We found that viruses were widely distributed in a variety of hydrothermal microbial habitats, with the exception of the interior parts of hydrothermal chimney structures. The VLP abundance and VLP-to-prokaryote ratio (VPR) in the planktonic habitats increased as the ratio of hydrothermal fluid to mixing water increased. On the other hand, the VLP abundance in attached microbial communities was significantly and positively correlated with the whole prokaryotic abundance; however, the VPRs were always much lower than those for the surrounding hydrothermal waters. This is the first report to show VLP abundance in the attached microbial communities of submarine hydrothermal environments, which presented VPR values significantly lower than those in planktonic microbial communities reported before. These results suggested that viral lifestyles (e.g., lysogenic prevalence) and virus interactions with prokaryotes are significantly different among the planktonic and attached microbial communities that are developing in the submarine hydrothermal environments. PMID:22210205

Predicting plankton net community production in the Atlantic Ocean

Science.gov (United States)

Serret, Pablo; Robinson, Carol; Fernández, Emilio; Teira, Eva; Tilstone, Gavin; Pérez, Valesca

2009-07-01

We present, test and implement two contrasting models to predict euphotic zone net community production (NCP), which are based on 14C primary production (PO 14CP) to NCP relationships over two latitudinal (ca. 30°S-45°N) transects traversing highly productive and oligotrophic provinces of the Atlantic Ocean (NADR, CNRY, BENG, NAST-E, ETRA and SATL, Longhurst et al., 1995 [An estimation of global primary production in the ocean from satellite radiometer data. Journal of Plankton Research 17, 1245-1271]). The two models include similar ranges of PO 14CP and community structure, but differ in the relative influence of allochthonous organic matter in the oligotrophic provinces. Both models were used to predict NCP from PO 14CP measurements obtained during 11 local and three seasonal studies in the Atlantic, Pacific and Indian Oceans, and from satellite-derived estimates of PO 14CP. Comparison of these NCP predictions with concurrent in situ measurements and geochemical estimates of NCP showed that geographic and annual patterns of NCP can only be predicted when the relative trophic importance of local vs. distant processes is similar in both modeled and predicted ecosystems. The system-dependent ability of our models to predict NCP seasonality suggests that trophic-level dynamics are stronger than differences in hydrodynamic regime, taxonomic composition and phytoplankton growth. The regional differences in the predictive power of both models confirm the existence of biogeographic differences in the scale of trophic dynamics, which impede the use of a single generalized equation to estimate global marine plankton NCP. This paper shows the potential of a systematic empirical approach to predict plankton NCP from local and satellite-derived P estimates.

Reconstruction of paleo-inlet dynamics using sedimentologic analyses, geomorphic features, and benthic foraminiferal assemblages: former ephemeral inlets of Cedar Island, Virginia, USA

Science.gov (United States)

McBride, R.; Wood, E. T.

2017-12-01

Cedar Island, VA is a low-profile, washover-dominated barrier island that has breached at least three times in the past sixty years. Cedar Island Inlet, a former wave-dominated tidal inlet, was open for the following time periods: 1) 1956-1962, 2) 1992-1997, and 3) 1998-2007. Air photos, satellite imagery, and geomorphic features (i.e., relict flood tidal deltas, recurved-spit ridges) record the spatial and temporal extent of the three ephemeral inlets. Based on three sediment vibracores, benthic foraminiferal and sedimentologic analyses offer high resolution insights of inlet dynamics and lifecycle evolution. Four foraminiferal biofacies are completely dominated by Elphidium excavatum (54-100%) and contain unique assemblages of accessory species based on cluster analyses: tidal inlet floor (low abundance estuarine and shelf species; 23% Haynesina germanica); flood tidal delta/inlet fill (high abundance estuarine and shelf species; 2% Buccella frigida, 2% Ammonia parkinsoniana, and 2% Haynesina germanica); high-energy inlet fill (low abundance, low diversity shelf species; 9% Elphidium gunteri); and washover/beach/aeolian (low abundance, predominantly shelf species; 3% Buccella frigida and 3% Ammonia parkinsoniana). The estuarine biofacies is barren of all foraminifera. Grain size trends indicate a first order coarsening-upward succession with second order coarsening- and fining-upwards packages in inlet throat deposits, while a first order fining-upward succession is observed in flood tidal delta deposits with two second order coarsening-upward packages in the proximal flood tidal delta. Contrary to typical wave-dominated tidal inlets that open, migrate laterally in the direction of net longshore transport, and close, the 1998-2007 tidal inlet, and possibly the 1956-1962 inlet, migrated laterally and rotated, whereas the 1992-1997 inlet remained stationary and did not rotate. In the vicinity of the vibracores, preserved deposits are attributed to the 1956-1962 and

Plankton Assemblage Estimated with BGC-Argo Floats in the Southern Ocean: Implications for Seasonal Successions and Particle Export

Science.gov (United States)

Rembauville, Mathieu; Briggs, Nathan; Ardyna, Mathieu; Uitz, Julia; Catala, Philippe; Penkerc'h, Cristophe; Poteau, Antoine; Claustre, Hervé; Blain, Stéphane

2017-10-01

The Southern Ocean (SO) hosts plankton communities that impact the biogeochemical cycles of the global ocean. However, weather conditions in the SO restrict mainly in situ observations of plankton communities to spring and summer, preventing the description of biological successions at an annual scale. Here, we use shipboard observations collected in the Indian sector of the SO to develop a multivariate relationship between physical and bio-optical data, and, the composition and carbon content of the plankton community. Then we apply this multivariate relationship to five biogeochemical Argo (BGC-Argo) floats deployed within the same bio-geographical zone as the ship-board observations to describe spatial and seasonal changes in plankton assemblage. The floats reveal a high contribution of bacteria below the mixed layer, an overall low abundance of picoplankton and a seasonal succession from nano- to microplankton during the spring bloom. Both naturally iron-fertilized waters downstream of the Crozet and Kerguelen Plateaus show elevated phytoplankton biomass in spring and summer but they differ by a nano- or microplankton dominance at Crozet and Kerguelen, respectively. The estimated plankton group successions appear consistent with independent estimations of particle diameter based on the optical signals. Furthermore, the comparison of the plankton community composition in the surface layer with the presence of large mesopelagic particles diagnosed by spikes of optical signals provides insight into the nature and temporal changes of ecological vectors that drive particle export. This study emphasizes the power of BGC-Argo floats for investigating important biogeochemical processes at high temporal and spatial resolution.

MIDDLE EOCENE TO EARLY MIOCENE FORAMINIFERAL BIOSTRATIGRAPHY IN THE EPILIGURIAN SUCCESSION (NORTHERN APENNINES, ITALY

Directory of Open Access Journals (Sweden)

NICOLETTA MANCIN

2001-11-01

Full Text Available A quantitative biostratigraphical study was performed on the foraminiferal assemblages from 15 stratigraphic sections of the Epiligurian Succession (Middle Eocene-Early Miocene, Northern Apennines, Italy. This study enabled us to identify the presence of some of the standard bioevents and to note that other bioevents are absent or show a different chronostratigraphic range. Other additional bioevents, identified throughout the area, have therefore been utilised to improve the biostratigraphical resolution of the Epiligurian sediments. These bioevents include the massive extinction of the muricate species at the Bartonian/Priabonian boundary; the increasing abundance of Paragloborotalia opima opima near Subzone P21a/P21b and the Rupelian/Chattian boundaries; and the FO of Globoquadrina dehiscens at the Subzone N4a/N4b boundary. 

Mercury speciation in plankton from the Cabo Frio Bay, SE--Brazil.

Science.gov (United States)

Silva-Filho, Emmanoel V; Kütter, Vinicius T; Figueiredo, Thiago S; Tessier, Emmanuel; Rezende, Carlos E; Teixeira, Daniel C; Silva, Carlos A; Donard, Olivier F X

2014-12-01

Mercury (Hg) is considered a global pollutant, and the scientific community has shown great concern about its toxicity as it may affect the biota of entire systems, through bioaccumulation and bioamplification processes of its organic form, methylmercury (MeHg), along food web. However, few research studies deal with bioaccumulation of Hg from marine primary producers and the first-order consumers. So, this study aims to determine Hg distribution and concentration levels in phytoplankton and zooplankton in the Cabo Frio Bay, Brazil, a site influenced by coastal upwelling. The results from Hg speciation analyses show that inorganic mercury Hg(II) was the predominant specie in plankton from this bay. The annual Hg species distribution in plankton shown mean concentration of 2.00 ± 1.28 ng Hg(II) g(-1) and 0.15 ± 0.08 ng MeHg g(-1) wet weight (phytoplankton) and 2.5 ± 2.03 ng Hg(II) g(-1) and 0.25 ± 0.09 ng MeHg g(-1) wet weight (zooplankton). Therefore, upwelling zones should be considered in the Hg biogeochemical cycle models as a process that enhances Hg(II) bioaccumulation in plankton, raising its bioavailability and shelf deposition.

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.

LOGICAL SoCIETY OF INDIA Vol. 36, Dec. 1990, pp. 654 to 660 Pre-Monsoon Living Planktonic Foraminifera from the Southeastern Arabian Sea M. V. S. GUPTHA.. P. DIVAKAR NAlDU AND A. S. MURALINATH Nalional Institute of Oceanography, Dona Paula, Goa 403004...

Ether lipids of planktonic archae in the marine water column

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Hoefs, M.J.L.; Schouten, S.; King, L.L.; Wakeham, S.G.; Leeuw, J.W. de

1997-01-01

Acyclic and cyclic biphytanes derived from the membrane ether lipids of archaea were found in water column particulate and sedimentary organic matter from several oxic and anoxic marine environments. Compound-specific isotope analyses of the carbon skeletons suggest that planktonic archaea utilize

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...

Plankton dynamics associated with the convergence zone of a shear ...

African Journals Online (AJOL)

Multiple linear regression was used to determine the relationships between water quality variables and plankton abundances. Community analysis was also run on the data in order to determine community dynamics associated with frontal system convergence and downwelling. Key words: ichthyoplankton, phytoplankton, ...

The Continuous Plankton Imaging and Classification Sensor (CPICS): A Sensor for Quantifying Mesoplankton Biodiversity and Community Structure

Science.gov (United States)

Gallager, S. M.

2016-02-01

Marine ecosystems are changing at a variety of time scales as a function of a diverse suite of forcing functions both natural and anthropogenic. Establishing a continuous plankton time series consisting of scales from rapid (seconds) to long-term (decades), provides a sentinel for ecosystem change. The key is to measure plankton biodiversity at sufficiently fast time scales that allow disentanglement of physical (transport) and biological (growth) properties of an ecosystem. CPICS is a plankton and particle imaging microscope system that is designed to produce crisp darkfield images of light scattering material in aquatic environments. The open flow design is non-invasive and non-restrictive providing images of very fragile plankton in their natural orientation. Several magnifications are possible from 0.5 to 5x forming a field of view of 10cm to 1mm, respectively. CPICS has been installed on several cabled observing systems called OceanCubes off the coast of Okinawa and Tokyo, Japan providing a continuous stream of plankton images to a machine vision image classifier located at WHOI. Image features include custom algorithms for texture, color pattern, morphology and shape, which are extracted from in-focus target. The features are then used to train a classifier (e.g., Random Forest) resulting in classifications that are tested using cross-validation, confusion matrices and ROC curves. High (>90%) classification accuracies are possible depending on the number of training categories and target complexity. A web-based utility allows access to raw images, training sets, classifiers and classification results. Combined with chemical and physical data from the observatories, an ecologically meaningful plankton index of biodiversity and its variance is developed using a combination of species and taxon groups, which provides an approach for understanding ecosystem change without the need to identify all targets to species. http://oceancubes.whoi.edu/instruments/CPICS

Modern foraminiferal facies in a subtropical estuarine channel, Bertioga, São Paulo, Brazil

Science.gov (United States)

Eichler, P.P.B.; Eichler, B.B.; De Miranda, L. B.; Rodrigues, A.R.

2007-01-01

Numerical analyses of modern foraminiferal abundance and environmental data from the Bertioga Channel (Sa??o Paulo, Brazil) reveal multiple biofacies within an overall paralic setting. Despite its fisheries, mariculture and attraction to tourists, the environmental state of Bertioga Channel remains poorly studied. The present investigation is an attempt to partly fill this gap; the parameters examined include depth, salinity, temperature, organic carbon, sulfur content and bottom sediment type. Muddy sediments with high organic carbon content derived from land drainage are found in the inner parts of the channel, whereas sandy sediment dominates the areas adjacent to the Atlantic Ocean. In the eastern entrance to the channel, sandy sediment contain species of Rotaliida from Facies 1 (including Elphidium discoidale, Elphidium poeyanum, Hanzawaia boueana, Pararotalia cananeiaensis and Nonionella atlantica), reflecting normal marine salinity. Sediments with high percentages of silt and clay in polyhaline and eurybaline environments of the eastern part and Itapanhau?? River contain Facies 2, which includes Ammonia beccarii and Pararotalia cananeiaensis. In the western entrance and central, western and eastern parts, where salinities vary from 18 to 30 psu and the sediments contain both low and high organic carbon, the foraminifera from Facies 3 are dominated by Quinqueloculina milletti, Arenoparrella mexicana, Pararotalia cananeiaensis, Ammonia beccarii, Buliminella elegantissima, Elphidium sp., Elphidium excavatum, Elphidium gunteri and Elphidium poeyanum. In mesohaline and polyhaline waters of the central part, the organic-carbon-rich silt and clay contain Facies 4, which includes Ammonia beccarii, Pararotalia cananeiaensis, Elphidium excavatum and Elphidium sp. Most of organic-carbon-enriched, silty-clay substrates that are subject to the highest fresh-water discharge and high bottom temperatures support two different assemblages: one of mostly Rotaliina and the

Slipstream: an early Holocene slump and turbidite record from the frontal ridge of the Cascadia accretionary wedge off western Canada and paleoseismic implications

Science.gov (United States)

Hamilton, T.S.; Enkin, Randolph J.; Riedel, Michael; Rogers, Gary C.; Pohlman, John W.; Benway, Heather M.

2015-01-01

Slipstream Slump, a well-preserved 3 km wide sedimentary failure from the frontal ridge of the Cascadia accretionary wedge 85 km off Vancouver Island, Canada, was sampled during Canadian Coast Guard Ship (CCGS) John P. Tully cruise 2008007PGC along a transect of five piston cores. Shipboard sediment analysis and physical property logging revealed 12 turbidites interbedded with thick hemipelagic sediments overlying the slumped glacial diamict. Despite the different sedimentary setting, atop the abyssal plain fan, this record is similar in number and age to the sequence of turbidites sampled farther to the south from channel systems along the Cascadia Subduction Zone, with no extra turbidites present in this local record. Given the regional physiographic and tectonic setting, megathrust earthquake shaking is the most likely trigger for both the initial slumping and subsequent turbidity currents, with sediments sourced exclusively from the exposed slump face of the frontal ridge. Planktonic foraminifera picked from the resedimented diamict of the underlying main slump have a disordered cluster of 14C ages between 12.8 and 14.5 ka BP. For the post-slump stratigraphy, an event-free depth scale is defined by removing the turbidite sediment intervals and using the hemipelagic sediments. Nine14C dates from the most foraminifera-rich intervals define a nearly constant hemipelagic sedimentation rate of 0.021 cm/year. The combined age model is defined using only planktonic foraminiferal dates and Bayesian analysis with a Poisson-process sedimentation model. The age model of ongoing hemipelagic sedimentation is strengthened by physical property correlations from Slipstream events to the turbidites for the Barkley Canyon site 40 km south. Additional modelling addressed the possibilities of seabed erosion or loss and basal erosion beneath turbidites. Neither of these approaches achieves a modern seabed age when applying the commonly used regional marine 14C reservoir age of

Vertical distribution and isotopic composition of living planktonic foraminifera in the western North Atlantic

International Nuclear Information System (INIS)

Fairbanks, R.G.; Wiebe, P.H.; Be, A.W.H.

1980-01-01

Thirteen species of planktonic foraminifera collected with vertically stratified zooplankton tows in the slope water, Gulf Stream cold core ring, and northern Sargasso Sea show significant differences in their vertical distributions in the upper 200 meters of these different hydrographic regimes. Gulf Stream cold core rings may be responsible for a southern displacement of the faunal boundary associated with the Gulf Stream when reconstructed from the deep-sea sediment record. Oxygen isotope analyses of seven species reveal that nonspinose species (algal symbiont-barren) apparently calcify in oxygen isotope equilibrium, whereas spinose species usually calcify out of oxygen isotope equilibrium by approximately -0.3 to -0.4 per mil in delta 18 O values. The isotope data indicate that foraminifera shells calcify in depth zones that are significantly narrower than the overall vertical distribution of a species would imply

Corroded planktic foraminifer (Globorotalia menardii) in the southern Bay of Bengal sediment trap sample of February 1992

Digital Repository Service at National Institute of Oceanography (India)

Mohan, R.; Guptha, M.V.S.

SEDIMENT TRAP 227 Fig.2. (a) Time series data of Total planktic foraminiferal flux [Yl axis Deep trap/ Left axis; Y2 axis Shallow trap/Right axis] for the period Feb.05, 1992 to Nov.20, 1992. (b) Time series data of Globorotalia menardii flux [Yl Deep... trap/ Left axis; Y2 axis Shallow trap /Right axis] for the period Feb.05, 1992 to Nov.20, 1992. (Note only 07 samples collected by the deep sediment trap). The Dotted Line indicates Deep trap;.Solid Line indicates Shallow trap. tests in plankton...

Cordilleran Ice Sheet meltwater delivery to the coastal waters of the northeast Pacific Ocean

Science.gov (United States)

Hendy, I. L.; Taylor, M.; Gombiner, J. H.; Hemming, S. R.; Bryce, J. G.; Blichert-Toft, J.

2014-12-01

Cordilleran Ice Sheet (CIS) delivered meltwater to the NE Pacific Ocean off BC and WA via glacial lake outburst floods (GLOFs), ice rafting and subglacial meltwater discharge. A deglacial glaciomarine sedimentation record is preserved in the well dated ~50-kyr core MD02-2496 (48˚58.47' N, 127˚02.14' W, water depth 1243 m), collected off Vancouver Island. To understand the history of the relationship between the CIS, climate and meltwater discharge, high resolution, multi-proxy geochemical records from the interval that captures the Fraser Glaciation (~30-10 ka) were generated. These proxies include Mg/Ca temperatures and δ18Oseawater from planktonic foraminiferal sp. N. pachyderma and G. bulloides, elemental and organic carbon (Corg) geochemistry of bulk sediments, ɛNd and K/Ar dating of the rose by > 3°C to 10-12°C in association with an additional IRD event at ~14.8 ka sourced from a ~75 Ma felsic volcanic source, likely the Southern Coast Plutonic Complex. At no point in the δ18Oseawater reconstruction is an obvious meltwater isotopic signature recorded despite the sedimentary evidence for both ice rafting and outburst flooding. Thus CIS meltwater likely entered the NE Pacific Ocean via hyperpycnal flow.

Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria.

Science.gov (United States)

Tonetta, D; Laudares-Silva, R; Petrucio, M M

2015-05-01

Planktonic primary production and respiration rates were estimated in a subtropical coastal lake dominated by Cyanobacteria in order to investigate the temporal and vertical variation in this lake and to evaluate its relationships with limnological variables and phytoplankton. Light and dark bottles were incubated at four different depths in the central part of the lake and were performed bimonthly from June/2009 to December/2010. No significant difference was evident among depths in relation to phytoplankton, limnological variables and metabolic rates. However, the highest production rates were recorded at the surface, and decreased towards the bottom, coupled with phytoplanktonic photosynthetic capacity. Wind induced mixing in Peri Lake played an important role in nutrient and phytoplankton redistribution, characterizing this lake as polymictic. According to density and biovolume, the phytoplankton community was dominated by filamentous Cyanobacteria, especially Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba-Raju. This study has shown that both water temperature and nutrient availability drive phytoplankton growth and consequently the temporal variation in metabolic rates, where respiration is higher than primary production.

Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria

Directory of Open Access Journals (Sweden)

D. Tonetta

Full Text Available Planktonic primary production and respiration rates were estimated in a subtropical coastal lake dominated by Cyanobacteria in order to investigate the temporal and vertical variation in this lake and to evaluate its relationships with limnological variables and phytoplankton. Light and dark bottles were incubated at four different depths in the central part of the lake and were performed bimonthly from June/2009 to December/2010. No significant difference was evident among depths in relation to phytoplankton, limnological variables and metabolic rates. However, the highest production rates were recorded at the surface, and decreased towards the bottom, coupled with phytoplanktonic photosynthetic capacity. Wind induced mixing in Peri Lake played an important role in nutrient and phytoplankton redistribution, characterizing this lake as polymictic. According to density and biovolume, the phytoplankton community was dominated by filamentous Cyanobacteria, especially Cylindrospermopsis raciborskii (Woloszynska Seenayya and Subba-Raju. This study has shown that both water temperature and nutrient availability drive phytoplankton growth and consequently the temporal variation in metabolic rates, where respiration is higher than primary production.

An Experimental-Numerical Study of Small Scale Flow Interaction with Bioluminescent Plankton

National Research Council Canada - National Science Library

Latz, Michael

1998-01-01

Numerical and experimental approaches were used to investigate the effects of quantified flow stimuli on bioluminescence sUmulatidn at the small length and time scales appropriate for individual plankton...

Psd1 Effects on Candida albicans Planktonic Cells and Biofilms

Directory of Open Access Journals (Sweden)

Sónia Gonçalves

2017-06-01

Full Text Available Candida albicans is an important human pathogen, causing opportunistic infections. The adhesion of planktonic cells to a substrate is the first step for biofilm development. The antimicrobial peptide (AMP Psd1 is a defensin isolated from Pisum sativum seeds. We tested the effects of this AMP on C. albicans biofilms and planktonic cells, comparing its activity with amphotericin B and fluconazole. Three C. albicans variants were studied, one of them a mutant deficient in glucosylceramide synthase, conferring resistance to Psd1 antifungal action. Atomic force microscopy (AFM was used to assess morphological and biomechanical changes on fungal cells. Surface alterations, with membrane disruption and leakage of cellular contents, were observed. Cytometry assays and confocal microscopy imaging showed that Psd1 causes cell death, in a time and concentration-dependent manner. These results demonstrate Psd1 pleiotropic action against a relevant fungal human pathogen, suggesting its use as natural antimycotic agent.

Marine Export Production and Remineralization During Early Eocene Hyperthermal Events at ODP Site 1263, Walvis Ridge, ODP Site 1209, Shatsky Rise and ODP Site 1215, Equatorial Pacific Ocean

Science.gov (United States)

Lewis, A.; Griffith, E. M.; Thomas, E.; Winguth, A. M. E.

2017-12-01

Understanding the impacts of global hyperthermal events on marine productivity and remineralization is important for understanding the reaction of the ocean to major climate change. Marine export production and remineralization was reconstructed using marine (pelagic) barite accumulation rates (BAR) coupled with records of benthic foraminiferal assemblages across the Paleocene - Eocene Thermal Maximum (PETM) at 55.3 Ma, Eocene Thermal Maximum 2 (ETM2) 2 Ma later, and ETM3 3.1 Ma after the PETM. Marine barite accumulates in deep sea sediment precipitating in the overlying water column during degradation of organic matter exported from the photic zone. Foraminiferal data indicate the amount of organic matter reaching the seafloor. We use the difference between these records to infer changes in rates of remineralization. We present data from ODP Site on Walvis Ridge, Southeastern Atlantic; ODP Site 1209 on Shatsky Rise, North Pacific; and ODP Site 1215, equatorial Pacific. Sites 1263 and 1215 had maximum BAR roughly centered over the maximum negative PETM CIE, whereas at Site 1209 the maximum was before the PETM. The maximum BAR across ETM2 and ETM3 (0.5 and 0.25 of that at the PETM, respectively) was centered over the maximum negative CIE at Site 1263. At Site 1209, the BAR (0.5 the maximum value before the PETM) peaked before ETM2. Barite concentration at Site 1215 was low across at the smaller hyperthermals, but the onset of ETM2 had a maximum value food arrival at the seafloor during elevated BAR, thus indicating enhanced remineralization. During the PETM, at all 3 sites, increases in barite coincided with reduced BFAR. Similar trends were observed during ETM2 at Sites 1263 and 1215, suggesting dramatic changes in remineralization over all hyperthermal events at these sites. Increased remineralization rates could partly account for differences in planktonic and benthic extinction, as observed during the PETM.

Design and calibration of a new optical plankton counter capable of sizing small zooplankton

Science.gov (United States)

Herman, Alex W.

1992-04-01

A new design of optical plankton counter (OPC) capable of sizing zooplankton in the size range of 256μ to 2 cm is presented. The detection sensitivity is the result of new optical design of the previous system ( HERMAN, 1988, Continental Shelf Research, 8, 205-221) that originally had a lower detection limit of 550 μm. Both theoretical and experimental calibrations for the OPC are derived and compared. Preserved copepods and eggs introduced in a flow tank demonstrate the response of the OPC and its capability for detecting plankton to a limit of 250 μm. Copepod profiles measured by the OPC mounted on plankton net samplers provided intercomparisons that showed good agreement in identifying copepod layers and identifying some species, for example, copepods as small as Calanus finmarchicus II and up to the adult stages. Profiles containing marine snow and Ceratium illustrate some of the limitations of the OPC in directly measuring and identifying copepods. An additional modification to the OPC may result in a potential lower limit detection of 120 μm, and the practicality of such applications are discussed.

Quantification and localization of trace metals in natural plankton using a synchrotron x-ray fluorescence microprobe

International Nuclear Information System (INIS)

Twining, B. S.; Baines, S. B.; Fisher, N. S.; Jacobsen, C.; Maser, J.; State Univ. of New York at Stony Brook

2003-01-01

The accumulation of trace metals by planktonic protists influences the growth of primary producers, metal biogeochemical cycling, and metal bioaccumulation in aquatic food chains. Despite their importance, unequivocal measurements of trace element concentrations in individual plankton cells have not been possible to date. We have used the 2-ID-E side-branch hard x-ray microprobe at the Advanced Photon Source to measure trace elements in individual marine plankton cells. This microprobe employs zoneplate optics to produce the sub-micron spatial resolution and low background fluorescence required to produce trace element maps of planktonic protist cells ranging in size from 3 to >50 (micro)m. We have developed preservation, rinsing, and mounting protocols that remove most of the salt from our marine samples, thus simplifying the identification of unknown cells and reducing high Cl-related background fluorescence. We have also developed spectral modeling techniques that account for the frequent overlap of adjacent fluorescence peaks and non-uniform detector response. Finally, we have used parallel soft x-ray transmission and epifluorescence microscopy images to estimate C normalized trace element concentrations, identify functional cell types (e.g., photosynthetic vs. non-photosynthetic), and correlate cell structures with spatial patterns in trace element fluorescence

Continuous daylight in the high-Arctic summer supports high plankton respiration rates compared to those supported in the dark

KAUST Repository

Mesa, Elena

2017-04-21

Plankton respiration rate is a major component of global CO2 production and is forecasted to increase rapidly in the Arctic with warming. Yet, existing assessments in the Arctic evaluated plankton respiration in the dark. Evidence that plankton respiration may be stimulated in the light is particularly relevant for the high Arctic where plankton communities experience continuous daylight in spring and summer. Here we demonstrate that plankton community respiration evaluated under the continuous daylight conditions present in situ, tends to be higher than that evaluated in the dark. The ratio between community respiration measured in the light (Rlight) and in the dark (Rdark) increased as the 2/3 power of Rlight so that the Rlight:Rdark ratio increased from an average value of 1.37 at the median Rlight measured here (3.62 µmol O2 L-1 d-1) to an average value of 17.56 at the highest Rlight measured here (15.8 µmol O2 L-1 d-1). The role of respiratory processes as a source of CO2 in the Arctic has, therefore, been underestimated and is far more important than previously believed, particularly in the late spring, with 24 h photoperiods, when community respiration rates are highest.

Temperature, salinity, transmissivity, pressure, plankton, oxygen, nutrients, chlorophyll, and primary productivity data collected using CTD, bottle, and plankton net from the R/V Italica in the Ross Sea and Magellan Strait during 10th Italian Antarctic Expedition from 1994-11-13 to 1995-04-02 (NCEI Accession 0068289)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, transmissivity, pressure, plankton, oxygen, nutrients, chlorophyll, and primary productivity data collected using CTD, bottle, and plankton...

Een methode ter bepaling van de respiratieaktiviteit in marien plankton

NARCIS (Netherlands)

Lambeck, R.H.D.

1973-01-01

The usefulness of a method, described by T.T. Packard (1971), for the determination of the potential respiratory rate in marine plankton, based on the use of tetrazolium dye, was tested. Especially the influence of a few aspects of the homogenisation procedure on the final results was investigated.

Response of planktonic bacteria of New Calabar River to zinc stress ...

African Journals Online (AJOL)

Response of planktonic bacteria of New Calabar River to zinc stress. ... The result of the in vitro study indicated that the bacterial strains are sensitive to Zn2+ stress. Therefore, Zn2+ contamination would ... Featuring journals from 32 Countries:.

Quasi-planktonic behavior of foraging top marine predators

Science.gov (United States)

Della Penna, Alice; de Monte, Silvia; Kestenare, Elodie; Guinet, Christophe; D'Ovidio, Francesco

2015-12-01

Monitoring marine top predators is fundamental for assessing the health and functioning of open ocean ecosystems. Although recently tracking observations have substantially increased, factors determining the horizontal exploration of the ocean by marine predators are still largely unknown, especially at the scale of behavioral switches (1-100 km, days-weeks). It is commonly assumed that the influence of water movement can be neglected for animals capable of swimming faster than the current. Here, we challenge this assumption by combining the use of biologging (GPS and accelerometry), satellite altimetry and in-situ oceanographic data (ADCP and drifting buoys) to investigate the effect of the mesoscale ocean dynamics on a marine predator, the southern elephant seal. A Lagrangian approach reveals that trajectories of elephant seals are characterized by quasi-planktonic bouts where the animals are horizontally drifting. These bouts correspond to periods of increased foraging effort, indicating that in the quasi-planktonic conditions energy is allocated to diving and chasing, rather than in horizontal search of favourable grounds. These results suggest that mesoscale features like eddies and fronts may act as a focal points for trophic interactions not only by bottom-up modulation of nutrient injection, but also by directly entraining horizontal displacements of the upper trophic levels.

Lack of congruence in species diversity indices and community structures of planktonic groups based on local environmental factors.

Science.gov (United States)

Doi, Hideyuki; Chang, Kwang-Hyeon; Nishibe, Yuichiro; Imai, Hiroyuki; Nakano, Shin-ichi

2013-01-01

The importance of analyzing the determinants of biodiversity and community composition by using multiple trophic levels is well recognized; however, relevant data are lacking. In the present study, we investigated variations in species diversity indices and community structures of the plankton taxonomic groups-zooplankton, rotifers, ciliates, and phytoplankton-under a range of local environmental factors in pond ecosystems. For each planktonic group, we estimated the species diversity index by using linear models and analyzed the community structure by using canonical correspondence analysis. We showed that the species diversity indices and community structures varied among the planktonic groups and according to local environmental factors. The observed lack of congruence among the planktonic groups may have been caused by niche competition between groups with similar trophic guilds or by weak trophic interactions. Our findings highlight the difficulty of predicting total biodiversity within a system, based upon a single taxonomic group. Thus, to conserve the biodiversity of an ecosystem, it is crucial to consider variations in species diversity indices and community structures of different taxonomic groups, under a range of local conditions.

Long-Term Trends and Temporal Synchrony in Plankton Richness, Diversity and Biomass Driven by Re-Oligotrophication and Climate across 17 Danish Lakes

Directory of Open Access Journals (Sweden)

Korhan Özkan

2016-09-01

Full Text Available A two-decade (1989–2008 time series of lake phyto- and zooplankton, water characteristics and climate in 17 Danish lakes was analysed to examine the long term changes and the effects of lake restoration efforts. The analyses of the pair-wise correlations across time series revealed a strong synchrony in climatic variables among the lakes. A significant, but weak increase in air temperature was observed and resulted in a corresponding increase in surface water temperature only in summer. Lake physico-chemical variables had weaker synchrony than climatic variables. Synchrony in water temperature and stratification was stronger than lake chemistry as the former is mostly affected by atmospheric energy flux. Synchrony in the taxonomic richness of the plankton groups and phytoplankton biomass was apparent, to a similar degree as observed for lake chemistry. The synchrony and the temporal trends in lake chemistry and plankton were more pronounced for the lakes with strong re-oligotrophication. Phytoplankton biomass decreased and plankton richness increased in these lakes, with a shift from Chlorophyta dominance towards more heterogeneous phytoplankton communities. Notably, a widespread significant positive trend in plankton richness was observed not only in lakes with strong re-oligotrophication but across all lakes. The widespread increase in plankton richness coincided with widespread decrease in phosphate and total nitrogen concentrations, as well as with the trends in climate indicating a likely joint effect of nutrient reduction and climate in driving lake plankton. However, temporal changes and synchrony as well as the recovery of richness and composition of lake plankton more coherently corresponded with the nutrient loading reduction across the Danish landscape, while the role of climate control of the lake plankton was less pronounced.

Middle Jurassic-Early Cretaceous foraminiferal biozonation of the Amran Group, eastern Sana'a Basin, Yemen

Science.gov (United States)

Al-Wosabi, Mohammed; El-Anbaawy, Mohammed; Al-Thour, Khalid

2017-06-01

Two sections of strata assigned to the Amran Group at Jabal Salab and Jabal Yam in the eastern Sana'a governorate were sampled and correlated. These sections are part of a carbonate platform that extends from the city of Marib in the east to Naqil Ibn Ghailan, 20 km east of the city of Sana'a to the west. Palaeontological analysis of samples recovered has resulted in identification of 123 foraminiferal species, which are used to subdivide the sequence of the Amran Group into five biostratigraphic zones, aged between Bathonian (Middle Jurassic) and Berriasian (Early Cretaceous). The proposed biozones are those of Riyadhella rotundata, Kurnubia jurassica, Ammomarginulina sinaica, Alveosepta jaccardi and Pseudocyclammina sulaiyana/Furitilla caspianseis. These biozones were constructed and correlated with the equivalent zones reported from several localities.

Middle Jurassic–Early Cretaceous foraminiferal biozonation of the Amran Group, eastern Sana’a Basin, Yemen

Directory of Open Access Journals (Sweden)

Al-Wosabi Mohammed

2017-06-01

Full Text Available Two sections of strata assigned to the Amran Group at Jabal Salab and Jabal Yam in the eastern Sana’a governorate were sampled and correlated. These sections are part of a carbonate platform that extends from the city of Marib in the east to Naqil Ibn Ghailan, 20 km east of the city of Sana’a to the west. Palaeontological analysis of samples recovered has resulted in identification of 123 foraminiferal species, which are used to subdivide the sequence of the Amran Group into five biostratigraphic zones, aged between Bathonian (Middle Jurassic and Berriasian (Early Cretaceous. The proposed biozones are those of Riyadhella rotundata, Kurnubia jurassica, Ammomarginulina sinaica, Alveosepta jaccardi and Pseudocyclammina sulaiyana/Furitilla caspianseis. These biozones were constructed and correlated with the equivalent zones reported from several localities.

Study the Seasonal Variability of Plankton and Forage Fish in the Gulf of Khambhat Using Npzfd Model

Science.gov (United States)

Kumar, V.; Kumar, S.

2016-02-01

Numerical modelling of marine ecology exploits several assumptions and it is indeed quite challenging to include marine ecological phenomena into a mathematical framework with too many unknown parameters. The governing ordinary differential equations represent the interaction of the biological and chemical processes in a marine environment. The key concern in the development of a numerical models are parameterizations based on output, viz., mathematical modelling of ecological system mainly depends on parameters and its variations. Almost, all constituents of each trophic level of marine food web are depended on phytoplankton, which are mostly influenced by initial slope of P-I curve and nutrient stock in the study domain. Whereas, the earlier plankton dynamic models rarely include a compartment of small fish and as an agent in zooplankton mortality, which is most important for the modelling of higher trophic level of marine species. A compartment of forage fish in the modelling of plankton dynamics has been given more realistic mortality rates of plankton, viz., they feed upon phytoplankton and zooplankton. The inclusion of an additional compartment increases complexity of earlier plankton dynamics model as it introduces additional unknown parameters, which has been specified for performing the numerical simulations.As a case study we applied our analysis to explain the aquatic ecology of Gulf of Khambhat (19o 48' N - 22o20' N, 65o E - 72o40' E), west coast of India, which has rich bio-diversity and a high productive area in the form of plankton and forage fish. It has elevated turbidity and varying geography location, viz., one of the regions among world's ocean with high biological productivity.The model presented in this study is able to bring out the essential features of the observed data; that includes the bimodal oscillations in the observed data, monthly mean chlorophyll-a in the SeaWiFs/MODIS Aqua data and in-situ data of plankton. The additional

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

Reduced calcification of marine plankton in response to increased atmospheric CO2.

Science.gov (United States)

Riebesell, U; Zondervan, I; Rost, B; Tortell, P D; Zeebe, R E; Morel, F M

2000-09-21

The formation of calcareous skeletons by marine planktonic organisms and their subsequent sinking to depth generates a continuous rain of calcium carbonate to the deep ocean and underlying sediments. This is important in regulating marine carbon cycling and ocean-atmosphere CO2 exchange. The present rise in atmospheric CO2 levels causes significant changes in surface ocean pH and carbonate chemistry. Such changes have been shown to slow down calcification in corals and coralline macroalgae, but the majority of marine calcification occurs in planktonic organisms. Here we report reduced calcite production at increased CO2 concentrations in monospecific cultures of two dominant marine calcifying phytoplankton species, the coccolithophorids Emiliania huxleyi and Gephyrocapsa oceanica. This was accompanied by an increased proportion of malformed coccoliths and incomplete coccospheres. Diminished calcification led to a reduction in the ratio of calcite precipitation to organic matter production. Similar results were obtained in incubations of natural plankton assemblages from the north Pacific ocean when exposed to experimentally elevated CO2 levels. We suggest that the progressive increase in atmospheric CO2 concentrations may therefore slow down the production of calcium carbonate in the surface ocean. As the process of calcification releases CO2 to the atmosphere, the response observed here could potentially act as a negative feedback on atmospheric CO2 levels.

Influence of ocean acidification and deep water upwelling on oligotrophic plankton communities in the subtropical North Atlantic

DEFF Research Database (Denmark)

Taucher, Jan; Bach, Lennart T.; Boxhammer, Tim

2017-01-01

Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. Increasing evidence indicates that these changes-summarized by the term ocean acidification (OA)-can significantly affect marine food webs and biogeochemical...... cycles. However, current scientific knowledge is largely based on laboratory experiments with single species and artificial boundary conditions, whereas studies of natural plankton communities are still relatively rare. Moreover, the few existing community-level studies were mostly conducted in rather...... and successfully simulated a deep water upwelling event that induced a pronounced plankton bloom. Our study revealed significant effects of OA on the entire food web, leading to a restructuring of plankton communities that emerged during the oligotrophic phase, and was further amplified during the bloom...

Comparative proteomic analysis of Listeria monocytogenes exposed to enterocin AS-48 in planktonic and sessile states.

Science.gov (United States)

Caballero Gómez, Natacha; Abriouel, Hikmate; Ennahar, Said; Gálvez, Antonio

2013-10-15

Enterocin AS-48 is a cyclic peptide of great interest for application in food preservation and sanitation. In the present study, the proteome response of Listeria monocytogenes to purified enterocin AS-48 was studied under two different conditions: planktonic cells and sessile cells grown on polystyrene plates. Ten different proteins were differentially expressed in planktonic L. monocytogenes cells treated with 0.1 μg/ml enterocin AS-48 compared to the untreated controls. Overexpressed proteins were related to stress response (DnaK) or carbohydrate transport and metabolism, while underexpressed and unexpressed proteins were related to metabolism (such as glyceraldehyde-3-phosphate dehydrogenase, pyruvate oxidase, glutamate dehydrogenase or glutamate decarboxylase) or stress (GroEL). In the sessile state, L. monocytogenes cells tolerated up to 10 μg/ml bacteriocin, and the treated biofilm cells overexpressed a set of 11 proteins, some of which could be related to stress response (DnaK, GroEL), protein synthesis and carbohydrate metabolism, while glyceraldehyde-3-phosphate dehydrogenase was the only unexpressed protein. Some of the overexpressed proteins (such as elongation factor Tu and GroEL) could also be implicated in cell adhesion. These results suggest different cell responses of L. monocytogenes to enterocin AS-48 in the planktonic and in the sessile state, including stress response and cell metabolism proteins. While in the planktonic state the bacterium may tend to compensate for the cytoplasmic cell permeability changes induced by AS-48 by reinforcing carbohydrate transport and metabolism, sessile cells seem to respond by shifting carbohydrate metabolism and reinforcing protein synthesis. Stress response proteins also seem to be important in the response to AS-48, but the stress response seems to be different in planktonic and in sessile cells. © 2013.

Ecological dispersal barrier across the equatorial Atlantic in a migratory planktonic copepod

Science.gov (United States)

Goetze, Erica; Hüdepohl, Patricia T.; Chang, Chantel; Van Woudenberg, Lauren; Iacchei, Matthew; Peijnenburg, Katja T. C. A.

2017-11-01

Resolving the large-scale genetic structure of plankton populations is important to understanding their responses to climate change. However, few studies have reported on the presence and geographic extent of genetically distinct populations of marine zooplankton at ocean-basin scales. Using mitochondrial sequence data (mtCOI, 718 animals) from 18 sites across a basin-scale Atlantic transect (39°N-40°S), we show that populations of the dominant migratory copepod, Pleuromamma xiphias, are genetically subdivided across subtropical and tropical waters (global FST = 0.15, global ΦST = 0.21, both P marine plankton, and we suggest that this may be a dominant mechanism driving the large-scale genetic structure of zooplankton species. Our results also demonstrate the potential importance of the Atlantic equatorial province as a region of evolutionary novelty for the holoplankton.

Plankton community composition and vertical migration during polar night in Kongsfjorden

DEFF Research Database (Denmark)

Grenvald, Julie Cornelius; Callesen, Trine Abraham; Daase, Malin

2016-01-01

characterize the plankton community composition during the polar night using water samplers and zooplankton net samples (50, 64, 200, 1500 lm), supplemented by acoustics (ADCPs, 300 kHz), to address a previously unresolved question–which species of zooplankton perform diel vertical migration during the polar...

The ecology of plankton in biological oceanography: a tribute to Marta Estrada’s task

Directory of Open Access Journals (Sweden)

Jordi Solé

2016-09-01

Full Text Available Plankton ecology has been the object of intense research and progress in the last few decades. This has been partly due to technological advances that have facilitated the multidisciplinary and high-resolution sampling of ecosystems and improved experimentation and analytical methodologies, and to sophisticated modelling. In addition, exceptional researchers have had the vision to integrate all these innovative tools to form a solid theoretical background in ecology. Here we provide an overview of the outstanding research work conducted by Professor Marta Estrada and her pioneering contribution to different areas of research in the last four decades. Her research in biological oceanography has mainly focussed on phytoplankton ecology, taxonomy and physiology, the functional structure of plankton communities, and physical and biological interactions in marine ecosystems. She has combined a variety of field and laboratory approaches and methodologies, from microscopy to satellite observations, including in-depth statistical data analysis and modelling. She has been a reference for scientists all over the world. Here, her contributions to plankton ecology are summarized by some of her students and closest collaborators, who had the privilege to share their science and everyday experiences with her.

Stratification of archaeal membrane lipids in the ocean and implications for adaptation and chemotaxonomy of planktonic archaea.

Science.gov (United States)

Zhu, Chun; Wakeham, Stuart G; Elling, Felix J; Basse, Andreas; Mollenhauer, Gesine; Versteegh, Gerard J M; Könneke, Martin; Hinrichs, Kai-Uwe

2016-12-01

Membrane lipids of marine planktonic archaea have provided unique insights into archaeal ecology and paleoceanography. However, past studies of archaeal lipids in suspended particulate matter (SPM) and sediments mainly focused on a small class of fully saturated glycerol dibiphytanyl glycerol tetraether (GDGT) homologues identified decades ago. The apparent low structural diversity of GDGTs is in strong contrast to the high diversity of metabolism and taxonomy among planktonic archaea. Furthermore, adaptation of archaeal lipids in the deep ocean remains poorly constrained. We report the archaeal lipidome in SPM from diverse oceanic regimes. We extend the known inventory of planktonic archaeal lipids to include numerous unsaturated archaeal ether lipids (uns-AELs). We further reveal (i) different thermal regulations and polar headgroup compositions of membrane lipids between the epipelagic (≤ 100 m) and deep (>100 m) populations of archaea, (ii) stratification of unsaturated GDGTs with varying redox conditions, and (iii) enrichment of tetra-unsaturated archaeol and fully saturated GDGTs in epipelagic and deep oxygenated waters, respectively. Such stratified lipid patterns are consistent with the typical distribution of archaeal phylotypes in marine environments. We, thus, provide an ecological context for GDGT-based paleoclimatology and bring about the potential use of uns-AELs as biomarkers for planktonic Euryarchaeota. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Comparison of the cytotoxic effect of polystyrene latex nanoparticles on planktonic cells and bacterial biofilms

International Nuclear Information System (INIS)

Nomura, Toshiyuki; Fujisawa, Eri; Itoh, Shikibu; Konishi, Yasuhiro

2016-01-01

The cytotoxic effect of positively charged polystyrene latex nanoparticles (PSL NPs) was compared between planktonic bacterial cells and bacterial biofilms using confocal laser scanning microscopy, atomic force microscopy, and a colony counting method. Pseudomonas fluorescens, which is commonly used in biofilm studies, was employed as the model bacteria. We found that the negatively charged bacterial surface of the planktonic cells was almost completely covered with positively charged PSL NPs, leading to cell death, as indicated by the NP concentration being greater than that required to achieve single layer coverage. In addition, the relationship between surface coverage and cell viability of P. fluorescens cells correlated well with the findings in other bacterial cells (Escherichia coli and Lactococcuslactis). However, most of the bacterial cells that formed the biofilm were viable despite the positively charged PSL NPs being highly toxic to planktonic bacterial cells. This indicated that bacterial cells embedded in the biofilm were protected by self-produced extracellular polymeric substances (EPS) that provide resistance to antibacterial agents. In conclusion, mature biofilms covered with EPS exhibit resistance to NP toxicity as well as antibacterial agents.

Comparison of the cytotoxic effect of polystyrene latex nanoparticles on planktonic cells and bacterial biofilms

Energy Technology Data Exchange (ETDEWEB)

Nomura, Toshiyuki, E-mail: nomura@chemeng.osakafu-u.ac.jp; Fujisawa, Eri; Itoh, Shikibu; Konishi, Yasuhiro [Osaka Prefecture University, Department of Chemical Engineering (Japan)

2016-06-15

The cytotoxic effect of positively charged polystyrene latex nanoparticles (PSL NPs) was compared between planktonic bacterial cells and bacterial biofilms using confocal laser scanning microscopy, atomic force microscopy, and a colony counting method. Pseudomonas fluorescens, which is commonly used in biofilm studies, was employed as the model bacteria. We found that the negatively charged bacterial surface of the planktonic cells was almost completely covered with positively charged PSL NPs, leading to cell death, as indicated by the NP concentration being greater than that required to achieve single layer coverage. In addition, the relationship between surface coverage and cell viability of P. fluorescens cells correlated well with the findings in other bacterial cells (Escherichia coli and Lactococcuslactis). However, most of the bacterial cells that formed the biofilm were viable despite the positively charged PSL NPs being highly toxic to planktonic bacterial cells. This indicated that bacterial cells embedded in the biofilm were protected by self-produced extracellular polymeric substances (EPS) that provide resistance to antibacterial agents. In conclusion, mature biofilms covered with EPS exhibit resistance to NP toxicity as well as antibacterial agents.

Comparison of the cytotoxic effect of polystyrene latex nanoparticles on planktonic cells and bacterial biofilms

Science.gov (United States)

Nomura, Toshiyuki; Fujisawa, Eri; Itoh, Shikibu; Konishi, Yasuhiro

2016-06-01

The cytotoxic effect of positively charged polystyrene latex nanoparticles (PSL NPs) was compared between planktonic bacterial cells and bacterial biofilms using confocal laser scanning microscopy, atomic force microscopy, and a colony counting method. Pseudomonas fluorescens, which is commonly used in biofilm studies, was employed as the model bacteria. We found that the negatively charged bacterial surface of the planktonic cells was almost completely covered with positively charged PSL NPs, leading to cell death, as indicated by the NP concentration being greater than that required to achieve single layer coverage. In addition, the relationship between surface coverage and cell viability of P. fluorescens cells correlated well with the findings in other bacterial cells ( Escherichia coli and Lactococcus lactis). However, most of the bacterial cells that formed the biofilm were viable despite the positively charged PSL NPs being highly toxic to planktonic bacterial cells. This indicated that bacterial cells embedded in the biofilm were protected by self-produced extracellular polymeric substances (EPS) that provide resistance to antibacterial agents. In conclusion, mature biofilms covered with EPS exhibit resistance to NP toxicity as well as antibacterial agents.

Heterogeneity in physical, chemical and plankton-community structures in Lake Tanganyika

NARCIS (Netherlands)

Langenberg, V.T.; Tumba, J.M.; Tshibangu, K.; Lukwesa, C.; Chitamwebwa, D.; Bwebwa, D.; Makasa, L.; Roijackers, R.M.M.

2008-01-01

From 28 August to 6 September 1995, we monitored the lake-wide physical, chemical and biological properties of the pelagic waters in Lake Tanganyika. The aim of this study was to examine the spatial environmental variability and its relation to fluctuations in plankton abundance and community

Spindle-shaped Microstructures: Potential Models for Planktonic Life Forms on Other Worlds

Science.gov (United States)

Oehler, Dorothy Z.; Walsh, Maud M.; Sugitani, Kenichiro; House, Christopher H.

2014-01-01

Spindle-shaped, organic microstructures ("spindles") are now known from Archean cherts in three localities (Figs. 1-4): The 3 Ga Farrel Quartzite from the Pilbara of Australia [1]; the older, 3.3-3.4 Ga Strelley Pool Formation, also from the Pilbara of Australia [2]; and the 3.4 Ga Kromberg Formation of the Barberton Mountain Land of South Africa [3]. Though the spindles were previously speculated to be pseudofossils or epigenetic organic contaminants, a growing body of data suggests that these structures are bona fide microfossils and further, that they are syngenetic with the Archean cherts in which they occur [1-2, 4-10]. As such, the spindles are among some of the oldest-known organically preserved microfossils on Earth. Moreover, recent delta C-13 study of individual spindles from the Farrel Quartzite (using Secondary Ion Mass Spectrometry [SIMS]) suggests that the spindles may have been planktonic (living in open water), as opposed to benthic (living as bottom dwellers in contact with muds or sediments) [9]. Since most Precambrian microbiotas have been described from benthic, matforming communities, a planktonic lifestyle for the spindles suggests that these structures could represent a segment of the Archean biosphere that is poorly known. Here we synthesize the recent work on the spindles, and we add new observations regarding their geographic distribution, robustness, planktonic habit, and long-lived success. We then discuss their potential evolutionary and astrobiological significance.

Susceptibility of Salmonella Biofilm and Planktonic Bacteria to Common Disinfectant Agents Used in Poultry Processing.

Science.gov (United States)

Chylkova, Tereza; Cadena, Myrna; Ferreiro, Aura; Pitesky, Maurice

2017-07-01

Poultry contaminated with Salmonella enterica subsp. enterica are a major cause of zoonotic foodborne gastroenteritis. Salmonella Heidelberg is a common serotype of Salmonella that has been implicated as a foodborne pathogen associated with the consumption of improperly prepared chicken. To better understand the effectiveness of common antimicrobial disinfectants (i.e., peroxyacetic acid [PAA], acidified hypochlorite [aCH], and cetylpyridinium chloride [CPC]), environmental isolates of nontyphoidal Salmonella were exposed to these agents under temperature, concentration, and contact time conditions consistent with poultry processing. Under simulated processing conditions (i.e., chiller tank and dipping stations), the bacteriostatic and bactericidal effects of each disinfectant were assessed against biofilm and planktonic cultures of each organism in a disinfectant challenge. Log reductions, planktonic MICs, and mean biofilm eradication concentrations were computed. The biofilms of each Salmonella isolate were more resistant to the disinfectants than were their planktonic counterparts. Although PAA was bacteriostatic and bactericidal against the biofilm and planktonic Salmonella isolates tested at concentrations up to 64 times the concentrations commonly used in a chiller tank during poultry processing, aCH was ineffective against the same isolates under identical conditions. At the simulated 8-s dipping station, CPC was bacteriostatic against all seven and bactericidal against six of the seven Salmonella isolates in their biofilm forms at concentrations within the regulatory range. These results indicate that at the current contact times and concentrations, aCH and PAA are not effective against these Salmonella isolates in their biofilm state. The use of CPC should be considered as a tool for controlling Salmonella biofilms in poultry processing environments.

Influence of glyphosate in planktonic and biofilm growth of Pseudomonas aeruginosa

Directory of Open Access Journals (Sweden)

Ilana Schneider Lima

2014-09-01

Full Text Available This study evaluated the impact of different concentrations of glyphosate (Rondup® on planktonic and biofilm growth of P. aeruginosa. Aerobic and anaerobic cultures of P. aeruginosa ATCC®15442 inoculated in MHB + glyphosate (0.845 ppm, 1.690 ppm, 8.45 ppm, 16.90 ppm, 84.50 ppm, 169 ppm, 845 ppm, and 1690 ppm and cultured in normoxia and anoxia, following their OD560nm every hour for 24 h. Biofilms of adapted cells were formed in the presence of glyphosate (0.845 to 1690 ppm in normoxia and anoxia for 36 h. Glyphosate at concentrations higher than 84.5 ppm reduces the cell density of planktonic aerobic cultures (p 0.05, and more pronounced over 169 ppm. Anaerobic biofilms have their growth more readily favored (p < 0.05, regardless of concentration. In a concentration-dependent manner, glyphosate interferes with the growth ability of P. aeruginosa ATCC®15442.

Radiocarbon evidence that carbon from the Deepwater Horizon spill entered the planktonic food web of the Gulf of Mexico

International Nuclear Information System (INIS)

Chanton, J P; Wilson, R M; Mickle, A; Cherrier, J; Sarkodee-Adoo, J; Bosman, S; Graham, W M

2012-01-01

The Deepwater Horizon (Macondo) oil spill released large volumes of oil and gas of distinct carbon isotopic composition to the northern Gulf of Mexico, allowing Graham et al (2010 Environ. Res. Lett. 5 045301) to use stable carbon isotopes (δ 13 C) to infer the introduction of spilled oil into the planktonic food web. Surface ocean organic production and measured oil are separated by 5–7‰ in stable carbon isotope (δ 13 C) space, while in radiocarbon (Δ 14 C) space these two potential sources are separated by more than 1000‰. Thus radiocarbon isotopes provide a more sensitive tracer by which to infer possible introduction of Macondo oil into the food web. We measured Δ 14 C and δ 13 C in plankton collected from within 100 km of the spill site as well as in coastal and offshore DIC (dissolved inorganic carbon or ΣCO 2 ) to constrain surface production values. On average, plankton values were depleted in 14 C relative to surface DIC, and we found a significant linear correlation between Δ 14 C and δ 13 C in plankton. Cumulatively, these results are consistent with the hypothesis that carbon released from the Deepwater Horizon spill contributed to the offshore planktonic food web. Our results support the findings of Graham et al (2010 Environ. Res. Lett. 5 045301), but we infer that methane input may be important. (letter)

Iceberg and meltwater discharge events in the western Arctic Ocean since MIS 5: a comparison of sediment cores off the East Siberian and Chukchi margins

Science.gov (United States)

Xiao, W.; Wang, R.; Zhang, T.; Duan, X.; Polyak, L.

2017-12-01

In the Pleistocene the western Arctic Ocean was affected by deglacial discharge events from ice sheets in northern North America as well as the East Siberian and Chukchi margins. Distribution of Ice Rafted Debris (IRD) >250 μm and planktonic foraminiferal N. pachyderma (sin.) (Nps) δ18O and δ13C was compared in CHINARE sediment cores ARC2-M03 (Wang et al., 2013) and ARC3-P37 from the Chukchi Abyssal Plain and Northwind Ridge, respectively, to identify the impacts of icebergs and meltwater on paleoceanographic environments since MIS 5. The IRD is mainly composed of quartz grains and fragments of clastic rocks and detrital carbonates. The carbonates, mostly dolomites characteristic of the Canadian Arctic Archipelago (CAA) provenance, typically anti-correlate with quartz and clastic rocks, indicating different sources such as Chukchi-Alaskan or East Siberian margin. Most of the Nps δ18O depletions correspond to peaks in detrital carbonates, suggesting a strong influence of meltwater from the Laurentide Ice Sheet (LIS) on the western Arctic Ocean. A conspicuous dark gray interval interpreted to represent glacial/deglacial environments of MIS 4/3 age, shows a remarkable depletion in Nps δ13C along with high δ18O values and absence of IRD. This unusual signature may be related to a persistent sea-ice cover and/or high fluxes of terrigenous material with deglacial debris flows. In a younger grey interval corresponding to MIS2, high abundances of quartz and clastic rocks in the Northwind Ridge core ARC3-P37 indicate iceberg discharge from areas other than CAA, such as the Mackenzie LIS lobe or Chukchi-Alaskan margin. The MIS2-Holocene transition is marked by an increase in detrital carbonates co-occurring with Nps δ13C and δ18O depletion (Polyak et al., 2007), indicative of LIS iceberg/meltwater fluxes from the CAA. We note that stable-isotope events in the study area may go unnoticed because of gaps in foraminiferal records related to dissolution and/or adverse

Planktonic copepod community in the neritic area south western part of Tunis bay influenced by Meliane river supplies (south western Mediterranean sea)

OpenAIRE

Ben Lamine, Y.; Daly Yahia Kefi, O.; Daly Yahia, N.

2012-01-01

The Tunis bay is located in the North Estern coast of Tunisia and receives in its Western part flows from Meliane River. Our study aims to describe the composition and the spatiotemporal distribution of planktonic copepods in the bay in order to identify the effect of the Meliane River supplies on the community. A grid of 19 stations was investigated monthly from July 2004 to December 2004 using a 160 μm mesh size plankton net, towed obliquely from the bottom to the surface. The planktonic co...

Studies on planktonic decapoda and stomatopoda (Crustacea) from the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Paulinose, V.T.; Goswami, S.C.; Nair, V.R.

and longitudes 66 degrees 00' and 78 degrees 00'E and depths ranging from 25 to 500 m. Only 40 samples out of 93, contained planktonic decapods and stomatopods. Maximum number of larvae (1501/100 m3) was obtained from Station 228 (Ga. Cr. 13), a very shallow...

Effects of solar ultraviolet radiation (UVR) on molecular diversity of plankton from the Chubut rivers estuary

International Nuclear Information System (INIS)

Manrique, J.M.; Halac, S.; Calvo, A.Y.; Villafane, V.; Jones, L.R.; Helbling, W.E.

2010-01-01

Within the framework of a project designed to evaluate the impact of UVR upon estuarine plankton, we present here a molecular analysis of plankton diversity. Water samples were exposed to three radiation treatments (PAR, PAR + UV-A and PAR + UV-A + UV-B) in microcosms for ca 10 days during the Austral summer. At the beginning (t 0 ) and at the end of the experiment samples were filtered 0 through 20, 10, 5 and 0.22 μm pore sizes. The DNA amount retained in each filter indicated that most of the plankton biomass was in the 0.22-5 μm fraction at t0. In contrast, at the end of the experiment this proportion changed according to the radiation treatment and big cells (> 20 μm) dominated. An rDNA library was obtained from the DNA corresponding to the 0.22-5 μm fraction. There was no relationship between treatments and the number and frequency of restriction genotypes. Analyses of 27 clones fraction from t 0 indicated the presence of three genera of Rhodobacteraceae, one genus of Rhodospirillaceae, one SAR11 genus, one genus of Bacillaceae, an unclassified sequences of Alphaproteobacteria, Actinobacteria and Rhodospirillaceae. Also, there were six sequences similar to Ostreococcus tauri (Mamiellales). Even though the sequence analyses are still ongoing, our initial data suggest a big impact of UV-B radiation in the amount and composition of the plankton community towards big cells. (authors)

Metabarcoding and metabolome analyses of copepod grazing reveal feeding preference and linkage to metabolite classes in dynamic microbial plankton communities.

Science.gov (United States)

Ray, Jessica L; Althammer, Julia; Skaar, Katrine S; Simonelli, Paolo; Larsen, Aud; Stoecker, Diane; Sazhin, Andrey; Ijaz, Umer Z; Quince, Christopher; Nejstgaard, Jens C; Frischer, Marc; Pohnert, Georg; Troedsson, Christofer

2016-11-01

In order to characterize copepod feeding in relation to microbial plankton community dynamics, we combined metabarcoding and metabolome analyses during a 22-day seawater mesocosm experiment. Nutrient amendment of mesocosms promoted the development of haptophyte (Phaeocystis pouchetii)- and diatom (Skeletonema marinoi)-dominated plankton communities in mesocosms, in which Calanus sp. copepods were incubated for 24 h in flow-through chambers to allow access to prey particles (<500 μm). Copepods and mesocosm water sampled six times spanning the experiment were analysed using metabarcoding, while intracellular metabolite profiles of mesocosm plankton communities were generated for all experimental days. Taxon-specific metabarcoding ratios (ratio of consumed prey to available prey in the surrounding seawater) revealed diverse and dynamic copepod feeding selection, with positive selection on large diatoms, heterotrophic nanoflagellates and fungi, while smaller phytoplankton, including P. pouchetii, were passively consumed or even negatively selected according to our indicator. Our analysis of the relationship between Calanus grazing ratios and intracellular metabolite profiles indicates the importance of carbohydrates and lipids in plankton succession and copepod-prey interactions. This molecular characterization of Calanus sp. grazing therefore provides new evidence for selective feeding in mixed plankton assemblages and corroborates previous findings that copepod grazing may be coupled to the developmental and metabolic stage of the entire prey community rather than to individual prey abundances. © 2016 John Wiley & Sons Ltd.

New perspectives on the functioning and evolution of photosymbiosis in plankton

Science.gov (United States)

Decelle, Johan

2013-01-01

Photosymbiosis is common and widely distributed in plankton and is considered to be beneficial for both partners (mutualism). Such intimate associations involving heterotrophic hosts and microalgal symbionts have been extensively studied in coral reefs, but in the planktonic realm, the ecology and evolution of photosymbioses remain poorly understood. Acantharia (Radiolaria) are ubiquitous and abundant heterotrophic marine protists, many of which host endosymbiotic microalgae. Two types of photosymbiosis involving acantharians have recently been described using molecular techniques: one found in a single acantharian species involving multiple microalgal partners (dinoflagellates and haptophytes), and the other observed in more than 25 acantharian species exclusively living with the haptophyte Phaeocystis. Contrary to most benthic and terrestrial mutualistic symbioses, these symbiotic associations share the common feature of involving symbionts that are abundant in their free-living stage. We propose a hypothetical framework that may explain this original mode of symbiosis, and discuss the ecological and evolutionary implications. We suggest that photosymbiosis in Acantharia, and probably in other planktonic hosts, may not be a mutualistic relationship but rather an “inverted parasitism,” from which only hosts seem to benefit by sequestrating and exploiting microalgal cells. The relatively small population size of microalgae in hospite would prevent reciprocal evolution that can select uncooperative symbionts, therefore making this horizontally-transmitted association stable over evolutionary time. The more we learn about the diversity of life and the structure of genomes, the more it appears that much of the evolution of biodiversity is about the manipulation of other species—to gain resources and, in turn, to avoid being manipulated (John Thompson, 1999). PMID:23986805

Large Plankton Enhance Heterotrophy Under Experimental Warming in a Temperate Coastal Ecosystem

KAUST Repository

Huete-Stauffer, Tamara Megan; Arandia-Gorostidi, Nestor; Gonzá lez-Bení tez, Natalia; Dí az-Pé rez, Laura; Calvo-Dí az, Alejandra; Moran, Xose Anxelu G.

2017-01-01

in February, April, August and October 2013 in coastal NE Atlantic waters, we monitored microbial plankton stocks and daily rates of primary production, bacterial heterotrophic production and respiration at in situ temperature and at 2 and 4°C over ambient

Arsenic in water, plankton and sediments off Goa coast and adjacent regions

Digital Repository Service at National Institute of Oceanography (India)

Fondekar, S.P.; Shirodkar, P.V.; Joseph, T.

as soluble inorganic arsenic and the rest as organic bound arsenic. Plankton and sediments also showed marked accumulation of this element, the average being 2.2 and 8.8 mu g/g respectively. Nearshore sediments showed higher values of arsenic indicating...

Klebsiella pneumoniae Planktonic and Biofilm Reduction by Different Plant Extracts: In Vitro Study

Directory of Open Access Journals (Sweden)

Lucas De Paula Ramos

2016-01-01

Full Text Available This study evaluated the action of Pfaffia paniculata K., Juglans regia L., and Rosmarius officinalis L. extracts against planktonic form and biofilm of Klebsiella pneumoniae (ATCC 4352. Minimum inhibitory concentration (MIC and minimum microbicidal concentration (MMC values were determined for each extract by microdilution broth method, according to Clinical and Laboratory Standards Institute. Next, antimicrobial activity of the extracts on biofilm was analyzed. For this, standardized suspension at 107 UFC/mL of K. pneumoniae was distributed into 96-well microplates (n=10 and after 48 h at 37°C and biofilm was subjected to treatment for 5 min with the extracts at a concentration of 200 mg/mL. ANOVA and Tukey tests (5% were used to verify statistical significant reduction (p<0.05 of planktonic form and biofilm. P paniculata K., R. officinalis L., and J. regia L. showed reductions in biomass of 55.6, 58.1, and 18.65% and cell viability reduction of 72.4, 65.1, and 31.5%, respectively. The reduction obtained with P. paniculata and R. officinalis extracts was similar to the reduction obtained with chlorhexidine digluconate 2%. In conclusion, all extracts have microbicidal action on the planktonic form but only P. paniculata K. and R. officinalis L. were effective against biofilm.

The influence of nitrogen inputs on biomass and trophic structure of ocean plankton: a study using biomass and stable isotope size-spectra

KAUST Repository

Mompeá n, Carmen; Bode, Antonio; Latasa, Mikel; Ferná ndez-Castro, Bieito; Mouriñ o-Carballido, Beatriz; Irigoien, Xabier

2016-01-01

Large scale patterns in planktonic food web structure were studied by applying continuous size-scaled models of biomass and δ15N to plankton samples, collected at 145 stations during the Malaspina-2010 Expedition across three ocean basins

Essential versus potentially toxic dietary substances: A seasonal comparison of essential fatty acids and methyl mercury concentrations in the planktonic food web

Energy Technology Data Exchange (ETDEWEB)

Kainz, Martin [Aquatic Ecosystem Management Research Division, National Water Research Institute, Environment Canada, 867 Lakeshore Road, P.O. Box 505, Burlington, ON L7R 4A6 (Canada)], E-mail: martin.kainz@donau-uni.ac.at; Arts, Michael T. [Water and Aquatic Sciences Research Program, University of Victoria, Department of Biology, P.O. Box 3020, Stn. CSC, Victoria, BC V8W 3N5 (Canada); Mazumder, Asit [Aquatic Ecosystem Management Research Division, National Water Research Institute, Environment Canada, 867 Lakeshore Road, P.O. Box 505, Burlington, ON L7R 4A6 (Canada)

2008-09-15

We investigated seasonal variability of essential fatty acids (EFA) and methyl mercury (MeHg) concentrations in four size categories of planktonic organisms in two coastal lakes. MeHg concentrations increased significantly with increasing plankton size and were independent of plankton taxonomy. However, total EFA increased from seston to mesozooplankton, but decreased in the cladoceran-dominated macrozooplankton size-class. Analysis of EFA patterns revealed that linoleic, alpha-linolenic, arachidonic, and eicosapentaenoic acids increased with increasing zooplankton size, but docosahexaenoic acid (DHA) in the cladoceran-dominated macrozooplankton was generally lower than in seston. This consistent pattern demonstrates that cladocerans, although bioaccumulating MeHg, convey less DHA than similar-sized copepods to their consumers. It is thus evident that fish consuming cladocerans have restricted access to DHA, yet unrestricted dietary access to MeHg. Thus, the structure of planktonic food webs clearly affects the composition of EFA and regulates dietary supply of these essential nutrients, while MeHg bioaccumulates with increasing zooplankton size. - The structure of planktonic food webs largely regulates the composition and dietary supply of essential fatty acids, while MeHg bioaccumulates with zooplankton size.

Essential versus potentially toxic dietary substances: A seasonal comparison of essential fatty acids and methyl mercury concentrations in the planktonic food web

International Nuclear Information System (INIS)

Kainz, Martin; Arts, Michael T.; Mazumder, Asit

2008-01-01

We investigated seasonal variability of essential fatty acids (EFA) and methyl mercury (MeHg) concentrations in four size categories of planktonic organisms in two coastal lakes. MeHg concentrations increased significantly with increasing plankton size and were independent of plankton taxonomy. However, total EFA increased from seston to mesozooplankton, but decreased in the cladoceran-dominated macrozooplankton size-class. Analysis of EFA patterns revealed that linoleic, alpha-linolenic, arachidonic, and eicosapentaenoic acids increased with increasing zooplankton size, but docosahexaenoic acid (DHA) in the cladoceran-dominated macrozooplankton was generally lower than in seston. This consistent pattern demonstrates that cladocerans, although bioaccumulating MeHg, convey less DHA than similar-sized copepods to their consumers. It is thus evident that fish consuming cladocerans have restricted access to DHA, yet unrestricted dietary access to MeHg. Thus, the structure of planktonic food webs clearly affects the composition of EFA and regulates dietary supply of these essential nutrients, while MeHg bioaccumulates with increasing zooplankton size. - The structure of planktonic food webs largely regulates the composition and dietary supply of essential fatty acids, while MeHg bioaccumulates with zooplankton size

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.

Planktonic foraminifer abundances, fluxes, test sizes, and coiling properties are influenced in various ways by the southwest monsoon winds and associated upwelling in the western Arabian Sea. The influence of monsoon driven upwelling...

Intraseasonal patterns in coastal plankton biomass off central Chile derived from satellite observations and a biochemical model

Science.gov (United States)

Gomez, Fabian A.; Spitz, Yvette H.; Batchelder, Harold P.; Correa-Ramirez, Marco A.

2017-10-01

Subseasonal (5-130 days) environmental variability can strongly affect plankton dynamics, but is often overlooked in marine ecology studies. We documented the main subseasonal patterns of plankton biomass in the coastal upwelling system off central Chile, the southern part of the Humboldt System. Subseasonal variability was extracted from temporal patterns in satellite data of wind stress, sea surface temperature, and chlorophyll from the period 2003-2011, and from a realistically forced eddy-resolving physical-biochemical model from 2003 to 2008. Although most of the wind variability occurs at submonthly frequencies (< 30 days), we found that the dominant subseasonal pattern of phytoplankton biomass is within the intraseasonal band (30-90 days). The strongest intraseasonal coupling between wind and plankton is in spring-summer, when increased solar radiation enhances the phytoplankton response to upwelling. Biochemical model outputs show intraseasonal shifts in plankton community structure, mainly associated with the large fluctuations in diatom biomass. Diatom biomass peaks near surface during strong upwelling, whereas small phytoplankton biomass peaks at subsurface depths during relaxation or downwelling periods. Strong intraseasonally forced changes in biomass and species composition could strongly impact trophodynamics connections in the ecosystem, including the recruitment of commercially important fish species such as common sardine and anchovy. The wind-driven variability of chlorophyll concentration was connected to mid- and high-latitude atmospheric anomalies, which resemble disturbances with frequencies similar to the tropical Madden-Julian Oscillation.

Cenomanian-Turanian anoxic event and potential petroleum source rocks of the Upper Benue Trough, Nigeria

International Nuclear Information System (INIS)

Mohammed, B.

2004-01-01

Foraminiferal palaeoenviromental studies particularly planktonic/benthonic (p/b) ratio have been used to demarcate anoxic horizon within the Cenomanian-Turonian sequence of the Upper Benue trough. The foraminiferal faunal assemblages indicate a deep marine .anoxic I sequences. Geochemical analysis of organic matter yielded TOC values that are generally fair to moderate with average of 0.70,2.05 and 0.44% in Dukkul, Pindiga and Gongila Formations respectively. Hydrogen indices also indicate preponderance of gas -prone terrestrial type III organic matter. This seems to be inconsistent with anoxic/dysoxic environments in which organic matter is generally expected to be commonly more abundant, better preserved and more lipid rich. Therefore, it is suggested here that such a relatively deep marine anoxic environment was subsequently raised tectonically to very shallow levels (raised oxygen-minimum zone) where terrestrial organic matter were washed into the anoxic water. These terrestrial contributions diluted and downgraded the anoxic level such that TOCs are generally low to moderate and organic matter became generally of type III and IV

Biofilms and planktonic cells of Deinococcus geothermalis in extreme environments

Science.gov (United States)

Panitz, Corinna; Reitz, Guenther; Rabbow, Elke; Rettberg, Petra; Flemming, Hans-Curt; Wingender, Jost; Froesler, Jan

In addition to the several extreme environments on Earth, Space can be considered as just another exceptional environment with a unique mixture of stress factors comprising UV radiation, vacuum, desiccation, temperature, ionizing radiation and microgravity. Life that processes in these environments can depend on the life forms and their state of living. The question is whether there are different strategies for individual microorganisms compared to communities of the same organisms to cope with the different factors of their surroundings. Comparative studies of the survi-val of these communities called biofilms and planktonic cell samples of Deinococcus geothermalis stand at the focal point of the presented investigations. A biofilm is a structured community of microorganisms that live encapsulated in a matrix of extracellular polymeric substances on a surface. Microorganisms living in a biofilm usually have significantly different properties to cooperate than individually living microorganisms of the same species. An advantage of the biofilm is increased resistance to various chemical and physical effects, while the dense extracellular matrix and the outer layer of the cells protect the interior of the microbial consortium. The space experiment BOSS (Biofilm organisms surfing Space) as part the ESA experimental unit EXPOSE R-2 with a planned launch date in July 2014 will be subsequently mounted on the Russian Svesda module outside the ISS. An international team of scientists coordinated by Dr. P. Rettberg will investigate the hypothesis whether microorganisms organized as biofilm outmatch the same microorganisms exposed individually in the long-term survival of the harsh environmental conditions as they occur in space and on Mars. Another protective function in the samples could be dust par-ticles for instance Mars regolith simulant contained inside the biofilms or mixed with the planktonic cells, as additional shelter especially against the extraterrestrial UV

Making sense of ocean biota: how evolution and biodiversity of land organisms differ from that of the plankton.

Science.gov (United States)

Smetacek, Victor

2012-09-01

The oceans cover 70% of the planet's surface, and their planktonic inhabitants generate about half the global primary production, thereby playing a key role in modulating planetary climate via the carbon cycle. The ocean biota have been under scientific scrutiny for well over a century, and yet our understanding of the processes driving natural selection in the pelagic environment - the open water inhabited by drifting plankton and free-swimming nekton - is still quite vague. Because of the fundamental differences in the physical environment, pelagic ecosystems function differently from the familiar terrestrial ecosystems of which we are a part. Natural selection creates biodiversity but understanding how this quality control of random mutations operates in the oceans - which traits are selected for under what circumstances and by which environmental factors, whether bottom-up or top-down - is currently a major challenge. Rapid advances in genomics are providing information, particularly in the prokaryotic realm, pertaining not only to the biodiversity inventory but also functional groups. This essay is dedicated to the poorly understood tribes of planktonic protists (unicellular eukaryotes) that feed the ocean's animals and continue to run the elemental cycles of our planet. It is an attempt at developing a conceptually coherent framework to understand the course of evolution by natural selection in the plankton and contrast it with the better-known terrestrial realm. I argue that organism interactions, in particular co-evolution between predators and prey (the arms race), play a central role in driving evolution in the pelagic realm. Understanding the evolutionary forces shaping ocean biota is a prerequisite for harnessing plankton for human purposes and also for protecting the oceanic ecosystems currently under severe stress from anthropogenic pressures.

Mid-Eocene (Bartonian) larger benthic foraminifera from southeastern Turkey and northeastern Egypt: New evidence for the palaeobiogeography of the Tethyan carbonate platforms

Science.gov (United States)

Sallam, Emad S.; Erdem, Nazire Özgen; Sinanoğlu, Derya; Ruban, Dmitry A.

2018-05-01

Larger benthic foraminiferal assemblages from the mid-Eocene (Bartonian) sedimentary successions of the Tethyan carbonate platforms have been studied in southeastern Turkey and northeastern Egypt. In the Hazro-Diyarbakir section (SE Turkey), small-medium miliolids and textularinids are identified from the lower intervals of the Hoya Formation, whereas alveolinids and soritids (porcellaneous) and orbitolinids (agglutinated) increase in diversity and abundance in the upper intervals. The Dictyoconus aegyptiensis (Chapman) and Somalina stefaninii Silvestri are recorded for the first time from the Hoya Formation. The larger benthic foraminiferal assemblage from the Hoya Formation shows a significant similarity to those reported from the Observatory Formation (coeval with the Sannor Formation) in the Cairo-Suez district (NE Egypt). The studied foraminiferal assemblages imply restricted lagoonal-tidal flat palaeoenvironments. Palaeobiogeographically, the larger benthic foraminiferal assemblages recorded in southeastern Turkey and northeastern Egypt carbonate platforms display a strong affinity to the Arabian, Middle East and African platforms. The position of the global sea-level and the plate tectonic organization of the studied region during the Bartonian were the main factors that facilitated faunal exchange within the carbonate platforms.

Spatio-temporal pattern formation, fractals, and chaos in conceptual ecological models as applied to coupled plankton-fish dynamics

International Nuclear Information System (INIS)

Medvinskii, Aleksandr B; Tikhonova, Irina A; Tikhonov, D A; Ivanitskii, Genrikh R; Petrovskii, Sergei V; Li, B.-L.; Venturino, E; Malchow, H

2002-01-01

The current turn-of-the-century period witnesses the intensive use of the bioproducts of the World Ocean while at the same time calling for precautions to preserve its ecological stability. This requires that biophysical processes in aquatic systems be comprehensively explored and new methods for monitoring their dynamics be developed. While aquatic and terrestrial ecosystems have much in common in terms of their mathematical description, there are essential differences between them. For example, the mobility of oceanic plankton is mainly controlled by diffusion processes, whereas terrestrial organisms naturally enough obey totally different laws. This paper is focused on the processes underlying the dynamics of spatially inhomogeneous plankton communities. We demonstrate that conceptual reaction-diffusion mathematical models are an appropriate tool for investigating both complex spatio-temporal plankton dynamics and the fractal properties of planktivorous fish school walks. (reviews of topical problems)

Microbial eukaryote plankton communities of high-mountain lakes from three continents exhibit strong biogeographic patterns.

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Filker, Sabine; Sommaruga, Ruben; Vila, Irma; Stoeck, Thorsten

2016-05-01

Microbial eukaryotes hold a key role in aquatic ecosystem functioning. Yet, their diversity in freshwater lakes, particularly in high-mountain lakes, is relatively unknown compared with the marine environment. Low nutrient availability, low water temperature and high ultraviolet radiation make most high-mountain lakes extremely challenging habitats for life and require specific molecular and physiological adaptations. We therefore expected that these ecosystems support a plankton diversity that differs notably from other freshwater lakes. In addition, we hypothesized that the communities under study exhibit geographic structuring. Our rationale was that geographic dispersal of small-sized eukaryotes in high-mountain lakes over continental distances seems difficult. We analysed hypervariable V4 fragments of the SSU rRNA gene to compare the genetic microbial eukaryote diversity in high-mountain lakes located in the European Alps, the Chilean Altiplano and the Ethiopian Bale Mountains. Microbial eukaryotes were not globally distributed corroborating patterns found for bacteria, multicellular animals and plants. Instead, the plankton community composition emerged as a highly specific fingerprint of a geographic region even on higher taxonomic levels. The intraregional heterogeneity of the investigated lakes was mirrored in shifts in microbial eukaryote community structure, which, however, was much less pronounced compared with interregional beta-diversity. Statistical analyses revealed that on a regional scale, environmental factors are strong predictors for plankton community structures in high-mountain lakes. While on long-distance scales (>10 000 km), isolation by distance is the most plausible scenario, on intermediate scales (up to 6000 km), both contemporary environmental factors and historical contingencies interact to shift plankton community structures. © 2016 John Wiley & Sons Ltd.

Ventilation changes in the western North Pacific since the last glacial period

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Y. Okazaki

2012-01-01

Full Text Available We reconstructed the ventilation record of deep water at 2100 m depth in the mid-latitude western North Pacific over the past 25 kyr from radiocarbon measurements of coexisting planktic and benthic foraminiferal shells in sediment with a high sedimentation rate. The ¹⁴C data on fragile and robust planktic foraminiferal shells were concordant with each other, ensuring high quality of the reconstructed ventilation record. The radiocarbon activity changes were consistent with the atmospheric record, suggesting that no massive mixing of old carbon from the abyssal reservoir occurred throughout the glacial to deglacial periods.

[Changes in phytoperiphyton community during seasonal succession: influence of plankton sedimentation and grazing by phytophages--Chironomid larvae].

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Lukin, V B

2002-01-01

The investigation of seasonal changes in spatial structure of phytoperiphyton during succession was conducted at the lower reaches of Akulovsky water channel from April to August 2000. At the beginning of succession from April to June dominant forms were chain-forming diatoms and filamentous green algae, sedimented from plankton. Later, at the middle of June under increasing pressure of herbivorous, they were replaced by stretched unicellular diatoms and colonial cyanobacteria. In late June-August, when herbivorous predation was the most intensive, the relative abundance of typical periphytonic forms decreased while that of settled planktonic forms increased. The effect of planktonic algae sedimentation on periphyton composition was evaluated as similarity between phytoperiphyton and phytoplankton communities measured with Chekanovski--Sorensen index. The value of this index tends to decrease with the development of periphyton while showing some relation to intensity of herbivorous pressure. Minimal values of Chekanovski--Sorensen index were under moderate herbivorous density, whereas maximal values were observed in periods of extremely high or low herbivorous density.

Time dependent enhanced resistance against antibiotics & metal salts by planktonic & biofilm form of Acinetobacter haemolyticus MMC 8 clinical isolate

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Sharvari Vijaykumar Gaidhani

2014-01-01

Full Text Available Background & objectives: Available literature shows paucity of reports describing antibiotic and metal resistance profile of biofilm forming clinical isolates of Acinetobacter haemolyticus. The present study was undertaken to evaluate the antibiotic and metal resistance profile of Indian clinical isolate of A. haemolyticus MMC 8 isolated from human pus sample in planktonic and biofilm form. Methods: Antibiotic susceptibility and minimum inhibitory concentration were determined employing broth and agar dilution techniques. Biofilm formation was evaluated quantitatively by microtiter plate method and variation in complex architecture was determined by scanning electron microscopy. Minimum biofilm inhibiting concentration was checked by Calgary biofilm device. Results: Planktonic A. haemolyticus MMC 8 was sensitive to 14 antibiotics, AgNO 3 and HgC1 2 resistant to streptomycin and intermediately resistant to netilmycin and kanamycin. MMC 8 exhibited temporal variation in amount and structure of biofilm. There was 32 - 4000 and 4 - 256 fold increase in antibiotic and metal salt concentration, respectively to inhibit biofilm over a period of 72 h as against susceptible planktonic counterparts. Total viable count in the range of 10 5 -10 6 cfu / ml was observed on plating minimum biofilm inhibiting concentration on Muller-Hinton Agar plate without antimicrobial agents. Biofilm forming cells were several folds more resistant to antibiotics and metal salts in comparison to planktonic cells. Presence of unaffected residual cell population indicated presence of persister cells. Interpretation & conclusions: The results indicate that biofilm formation causes enhanced resistance against antibiotics and metal salts in otherwise susceptible planktonic A. haemolyticus MMC 8.

Influence of plankton community structure on the sinking velocity of marine aggregates

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Bach, L. T.; Boxhammer, T.; Larsen, A.; Hildebrandt, N.; Schulz, K. G.; Riebesell, U.

2016-08-01

About 50 Gt of carbon is fixed photosynthetically by surface ocean phytoplankton communities every year. Part of this organic matter is reprocessed within the plankton community to form aggregates which eventually sink and export carbon into the deep ocean. The fraction of organic matter leaving the surface ocean is partly dependent on aggregate sinking velocity which accelerates with increasing aggregate size and density, where the latter is controlled by ballast load and aggregate porosity. In May 2011, we moored nine 25 m deep mesocosms in a Norwegian fjord to assess on a daily basis how plankton community structure affects material properties and sinking velocities of aggregates (Ø 80-400 µm) collected in the mesocosms' sediment traps. We noted that sinking velocity was not necessarily accelerated by opal ballast during diatom blooms, which could be due to relatively high porosity of these rather fresh aggregates. Furthermore, estimated aggregate porosity (Pestimated) decreased as the picoautotroph (0.2-2 µm) fraction of the phytoplankton biomass increased. Thus, picoautotroph-dominated communities may be indicative for food webs promoting a high degree of aggregate repackaging with potential for accelerated sinking. Blooms of the coccolithophore Emiliania huxleyi revealed that cell concentrations of 1500 cells/mL accelerate sinking by about 35-40%, which we estimate (by one-dimensional modeling) to elevate organic matter transfer efficiency through the mesopelagic from 14 to 24%. Our results indicate that sinking velocities are influenced by the complex interplay between the availability of ballast minerals and aggregate packaging; both of which are controlled by plankton community structure.

Ecology of planktonic foraminifera and their symbiotic algae

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Gastrich, M.D.

1986-01-01

Two types of symbiotic algae occurred abundantly and persistently in the cytoplasm of several species of planktonic Foraminifera over a ten year period in different tropical and subtropical areas of the North Atlantic Ocean. These planktonic Foraminifera host species consistently harbored either dinoflagellates or a newly described minute coccoid algal type. There appeared to be a specific host-symbiont relationship in these species regardless of year, season or geographic locality. The larger ovoid dinoflagellates (Pyrrhophycophyta) occur in the spinose species Globigerinoides ruber, Globigerinoides sacculifer, G. conglobatus and Orbulina universa. The smaller alga, from 1.5 to 3.5 um in diameter, occurs in one spinose species Globigerinella aequilateralis and also in the non-spinose species Globigerinita glutinata, Globoquadrina dutertrei, Globorotalia menardii, Globorotalia cristata, Globorotalia inflata, Candeina nitida, in various juvenile specimens and at all seasons except the winter months in Pulleniatina obliquiloculata and Globorotalial hirsuta. Controlled laboratory studies indicated a significant C incorporation into the host cytoplasm and inorganic calcium carbonate test of Globigerinoides ruber. During incubation for up to two hours, the 14 C uptake into the cytoplasm and test in the light was significantly greater than uptake in the dark by living specimens or by dead foraminifers. There appears to be light-enhanced uptake of 14 C into the test with dinoflagellate photosynthesis contributing to host calcification. In culture, symbiotic algae were observed to survive for the duration of the lifespan of their hosts

The first marine record of the Bartonian Nummulites and Calcareous nannofossils at the Tihoiyeh section of the Jiroft area (Central Iran)

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Hadi, Mehdi; Parandavar, Mohammad; Kiani-Shahvandi, Madineh; Dabaghi Sadr, Fatemeh

2016-04-01

The studied shallow marine sediments are situated south and southwest of Jiroft town, 180 km south of Keman, from the Tihoiyeh section (near Tihoiyeh village). These deposits at the top of the section include marly limestones with index Nummulites species such as N. perforatus (De Montfort), N. lyelli (D'Archiac and Haime). According to Schaub's nummulitic time scale (1981) and shallow benthic zonation of Serra-Kiel et al. (1998), this interval referred to Bartonian age and SBZ17 zone, respectively. Also, the calcareous nannofossil study on this interval led to identification of 19 well-preserved species belonging to 11 genera of this plankton group. Based on determined index calcareous nannofossiltaxa such as Reticulofenestra bisecta, Sphenolithus obtusus, Sphenolithus intercalaris, Cribrocentrum erbae and associated species such as Sphenolithus pseudoradians, Reticulofenestra wadeae, Cribrocentrum reticulatum and Blackites spinosus this interval assigned to the CNE15 zone of Agnini et al. (2014) that corresponds to upper part of NP16 and lower part of NP17 zones of Martini (1971). It is resulted that, the detected shallow benthic foraminifera zone, corresponds to the calcareous nannofossil zones both indicating Bartonian age. Keywords: Bartonian, Calcareous nannofossil, Nummulites, Central Iran, Tihoiyeh section. References: Agnini, C., Fornaciari, E., Raffi, I, Rita Catanzariti, R., Palike, H., Backman, J. and Rio, D., 2014. Biozonation and biochronology of Paleogene calcareous nannofossils from low and middle latitudes. Newsletters on Stratigraphy, Vol. 47 (2), Pp. 131-181. Martini, E., 1971. Standard Tertiary and Quaternary calcareous nannoplankton zonation. In: Farinacci, A. (Ed.), Proceedings 2nd International Conference Planktonic Microfossils Roma: Rome (Ed. Tecnosci.), 2, Pp. 739-785. Serra-Kiel, J., Hottinger, L., Caus, E., Drobne, K., Fernandez, C., Jauhri, A.K., Less, G., Pavlovec, R., Pignatti, J., Samso, J.M., Schaub, H., Sirel, E., Strougo, A

Ocean Acidification-Induced Restructuring of the Plankton Food Web Can Influence the Degradation of Sinking Particles

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Paul Stange

2018-04-01

Full Text Available Ocean acidification (OA is expected to alter plankton community structure in the future ocean. This, in turn, could change the composition of sinking organic matter and the efficiency of the biological carbon pump. So far, most OA experiments involving entire plankton communities have been conducted in meso- to eutrophic environments. However, recent studies suggest that OA effects may be more pronounced during prolonged periods of nutrient limitation. In this study, we investigated how OA-induced changes in low-nutrient adapted plankton communities of the subtropical North Atlantic Ocean may affect particulate organic matter (POM standing stocks, POM fluxes, and POM stoichiometry. More specifically, we compared the elemental composition of POM suspended in the water column to the corresponding sinking material collected in sediment traps. Three weeks into the experiment, we simulated a natural upwelling event by adding nutrient-rich deep-water to all mesocosms, which induced a diatom-dominated phytoplankton bloom. Our results show that POM was more efficiently retained in the water column in the highest CO2 treatment levels (>800 μatm pCO2 subsequent to this bloom. We further observed significantly lower C:N and C:P ratios in post-bloom sedimented POM in the highest CO2 treatments, suggesting that degradation processes were less pronounced. This trend is most likely explained by differences in micro- and mesozooplankton abundance during the bloom and post-bloom phase. Overall, this study shows that OA can indirectly alter POM fluxes and stoichiometry in subtropical environments through changes in plankton community structure.

Plankton community structure and connectivity in the Kimberley-Browse region of NW Australia

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McKinnon, A. D.; Duggan, S.; Holliday, D.; Brinkman, R.

2015-02-01

We describe the zooplankton and ichthyoplankton communities of coastal waters of the Kimberley coast (North West Australia), sampled in macrotidal Camden Sound during both the wet and dry seasons of 2011, and compare these to six other Kimberley embayments during the wet season of 2013. Zooplankton abundance in Camden Sound was 7038 ± 3913 SD ind. m-3 in the wet season and 1892 ± 708 SD ind. m-3 in the dry season, with copepods accounting for 85% by number. In all, 78 species of copepods were recorded, with the families Paracalanidae and Oithonidae dominant. In Camden Sound, 48 families of larval fish occurred, with ichthyoplankton more abundant in the wet season than the dry season (1.16 ± 0.2 ind. m-3 cf 0.76 ± 0.2 ind. m-3). Larval gobiids (Subfamily Gobiinae) were most abundant, with other common families associated with either pelagic or soft-bottom habitats as adults. Multivariate analyses of both copepod and ichthyoplankton communities demonstrated strong seasonal contrasts, although an along-shelf gradient in copepod community composition was apparent along the embayments sampled in 2013. There was little spatial variation in plankton communities within Camden Sound as a result of the large tidal range (up to 11.7 m, with 2.5 m-1 velocities), although gradients in abundance and composition on cross-shelf transects occurred in the more northern embayments that had a lower tidal range, such as Napier Broome Bay. Copepod communities of the Kimberley-Browse region were placed in regional perspective by multivariate analyses of similar data collected in the eastern Indian Ocean at Scott Reef, in the Arafura Sea and on the southern North West (NW) shelf. The plankton communities of the NW shelf form a series of along-shore metacommunities linked by advection, with weaker cross-shelf connectivity. The presence of the larvae of mesopelagic fishes of the family Myctophidae in coastal waters confirms seasonal cross-shelf connectivity.

Genomes of planktonic Acidimicrobiales: widening horizons for marine Actinobacteria by metagenomics.

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Mizuno, Carolina Megumi; Rodriguez-Valera, Francisco; Ghai, Rohit

2015-02-10

The genomes of four novel marine Actinobacteria have been assembled from large metagenomic data sets derived from the Mediterranean deep chlorophyll maximum (DCM). These are the first marine representatives belonging to the order Acidimicrobiales and only the second group of planktonic marine Actinobacteria to be described. Their streamlined genomes and photoheterotrophic lifestyle suggest that they are planktonic, free-living microbes. A novel rhodopsin clade, acidirhodopsins, related to freshwater actinorhodopsins, was found in these organisms. Their genomes suggest a capacity to assimilate C2 compounds, some using the glyoxylate bypass and others with the ethylmalonyl-coenzyme A (CoA) pathway. They are also able to derive energy from dimethylsulfopropionate (DMSP), sulfonate, and carbon monoxide oxidation, all commonly available in the marine habitat. These organisms appear to be prevalent in the deep photic zone at or around the DCM. The presence of sister clades to the marine Acidimicrobiales in freshwater aquatic habitats provides a new example of marine-freshwater transitions with potential evolutionary insights. Despite several studies showing the importance and abundance of planktonic Actinobacteria in the marine habitat, a representative genome was only recently described. In order to expand the genomic repertoire of marine Actinobacteria, we describe here the first Acidimicrobidae genomes of marine origin and provide insights about their ecology. They display metabolic versatility in the acquisition of carbon and appear capable of utilizing diverse sources of energy. One of the genomes harbors a new kind of rhodopsin related to the actinorhodopsin clade of freshwater origin that is widespread in the oceans. Our data also support their preference to inhabit the deep chlorophyll maximum and the deep photic zone. This work contributes to the perception of marine actinobacterial groups as important players in the marine environment with distinct and

Examination of a high resolution laser optical plankton counter and FlowCAM for measuring plankton concentration and size

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Kydd, Jocelyn; Rajakaruna, Harshana; Briski, Elizabeta; Bailey, Sarah

2018-03-01

Many commercial ships will soon begin to use treatment systems to manage their ballast water and reduce the global transfer of harmful aquatic organisms and pathogens in accordance with upcoming International Maritime Organization regulations. As a result, rapid and accurate automated methods will be needed to monitoring compliance of ships' ballast water. We examined two automated particle counters for monitoring organisms ≥ 50 μm in minimum dimension: a High Resolution Laser Optical Plankton Counter (HR-LOPC), and a Flow Cytometer with digital imaging Microscope (FlowCAM), in comparison to traditional (manual) microscopy considering plankton concentration, size frequency distributions and particle size measurements. The automated tools tended to underestimate particle concentration compared to standard microscopy, but gave similar results in terms of relative abundance of individual taxa. For most taxa, particle size measurements generated by FlowCAM ABD (Area Based Diameter) were more similar to microscope measurements than were those by FlowCAM ESD (Equivalent Spherical Diameter), though there was a mismatch in size estimates for some organisms between the FlowCAM ABD and microscope due to orientation and complex morphology. When a single problematic taxon is very abundant, the resulting size frequency distribution curves can become skewed, as was observed with Asterionella in this study. In particular, special consideration is needed when utilizing automated tools to analyse samples containing colonial species. Re-analysis of the size frequency distributions with the removal of Asterionella from FlowCAM and microscope data resulted in more similar curves across methods with FlowCAM ABD having the best fit compared to the microscope, although microscope concentration estimates were still significantly higher than estimates from the other methods. The results of our study indicate that both automated tools can generate frequency distributions of particles

Implementation of the zooplankton functional response in plankton models: State of the art, recent challenges and future directions

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Morozov, Andrew; Poggiale, Jean-Christophe; Cordoleani, Flora

2012-09-01

The conventional way of describing grazing in plankton models is based on a zooplankton functional response framework, according to which the consumption rate is computed as the product of a certain function of food (the functional response) and the density/biomass of herbivorous zooplankton. A large amount of literature on experimental feeding reports the existence of a zooplankton functional response in microcosms and small mesocosms, which goes a long way towards explaining the popularity of this framework both in mean-field (e.g. NPZD models) and spatially resolved models. On the other hand, the complex foraging behaviour of zooplankton (feeding cycles) as well as spatial heterogeneity of food and grazer distributions (plankton patchiness) across time and space scales raise questions as to the existence of a functional response of herbivores in vivo. In the current review, we discuss limitations of the ‘classical’ zooplankton functional response and consider possible ways to amend this framework to cope with the complexity of real planktonic ecosystems. Our general conclusion is that although the functional response of herbivores often does not exist in real ecosystems (especially in the form observed in the laboratory), this framework can be rather useful in modelling - but it does need some amendment which can be made based on various techniques of model reduction. We also show that the shape of the functional response depends on the spatial resolution (‘frame’) of the model. We argue that incorporating foraging behaviour and spatial heterogeneity in plankton models would not necessarily require the use of individual based modelling - an approach which is now becoming dominant in the literature. Finally, we list concrete future directions and challenges and emphasize the importance of a closer collaboration between plankton biologists and modellers in order to make further progress towards better descriptions of zooplankton grazing.

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...

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...

Proteorhodopsin lateral gene transfer between marine planktonic Bacteria and Archaea

DEFF Research Database (Denmark)

Frigaard, Niels-Ulrik; Martinez, Asuncion; Mincer, Tracy J

2006-01-01

Planktonic Bacteria, Archaea and Eukarya reside and compete in the ocean's photic zone under the pervasive influence of light. Bacteria in this environment were recently shown to contain photoproteins called proteorhodopsins, thought to contribute to cellular energy metabolism by catalysing light...... phylogenetic distribution of proteorhodopsins reflects their significant light-dependent fitness contributions, which drive the photoprotein's lateral acquisition and retention, but constrain its dispersal to the photic zone....

PARVULARUGOGLOBIGERINA EUGUBINA TYPE-SAMPLE AT CCESELLI (ITALY: PLANKTIC FORAMINIFERAL ASSEMBLAGE AND LOWERMOST DANIAN BIOSTRATIGRAPHIC IMPLICATIONS

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IGNACIO ARENILLAS

2000-11-01

Full Text Available The Parvularugoglobigerina eugubina Biozone (lowermost Danian was defined at Gubbio (Italy to precisely define the Cretaceous/Paleogene (K/P boundary. It was defined by the total range of Pv. eugubina, but this small morphospecies presents some taxonomic problems. The Pv. eugubina holotype and the planktic foraminiferal assemblage of the Pv. eugubina type-sample at Ceselli (Ceselli 3 were revised to precise the biostratigraphic position of this biozone. Of the 21 morphospecies identified in Ceselli 3, 14 are early Paleocene species and 7 are possible Cretaceous survivors of the K/P boundary extinction event. To clarify the lowermost Danian bizonation, it was necessary to taxonomically revise Pv. eugubina and Pv. longiapertura, which have both been identified in this sample. Following the definition of Pv. eugubina and the original definition of the nominal biozone, the base of Pv. eugubina Biozone should be placed at the first appearance datum of the eponymous species and not at the first appearance datum of Pv. longiapertura. 

Effect of water irrigation volume on Capsicum frutescens growth and plankton abundance in aquaponics system

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Andriani, Y.; Dhahiyat, Y.; Zahidah; Subhan, U.; Iskandar; Zidni, I.; Mawardiani, T.

2018-03-01

This study aimed to understand Capsicum frutescens growth and plankton abundance in aquaponics culture. A Completely Randomized Design (CRD) with six treatments in triplicates comprising of treatment A (positive control using organic liquid fertilizer), B (negative control without fertilizer), C (drip irrigation aquaponics with a water debit of 100 ml/day/plant), D (drip irrigation aquaponics with a water debit of 150 ml/day/plant), E (drip irrigation with a water debit of 200 ml/day/plant), and F (drip irrigation aquaponics with a water debit of 250 ml/day/plant) was applied. The water used in treatments C, D, E, and F contained comet fish feces as fertilizer. C. frutescens growth and plankton abundance were observed. Analysis was conducted using analysis of variance for plant productivity and descriptive analysis for plankton abundance and water quality. The results of this study showed that the highest plant growth was seen in plants receiving F treatment with 50 ml/day drip irrigation. However, no significant difference was found when compared to the positive control with organic artificial fertilizer. Eleven types of phytoplankton and six types of zooplankton were found, with Stanieria sp. as the most abundant phytoplankton and Brachionus sp. and Epistylis sp. as the most abundant zooplanktons.

The identification of plankton tropical status in the Wonokromo, Dadapan and Juanda extreme water estuary

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Sari, L. A.; Satyantini, W. H.; Manan, A.; Pursetyo, K. T.; Dewi, N. N.

2018-04-01

Wonokromo, Dadapan and Juanda estuaries are extreme waters located around Surabaya environment. This is because of a lot of organic material intake, which provided nutrients for plankton growth. In addition, the waters is also dynamic in reason of physico-chemical, geological and biological processes controlled by the tides and freshwater run-off from the river that empties into it. The objective of this study was to identify the presentation of plankton in extreme waters based on brightness and ammonia level. The study was conducted in January 2017. Three sampling locations were Wonokromo, Dadapan and Juanda estuaries. Each station consists of three points based on distances, which were 400, 700, and 1000 meters from the coastline. The brightness in Wonokromo, Dadapan, and Juanda environment was 60, 40, and 100 cm, respectively. The result of ammonia in Wonokromo, Dadapan, and Juanda estuary was 0.837, 0.626, and 0.396 mg/L, correspondingly. Nine classes of phytoplankton’s were found in three locations (bacillariophyceae, dynophyceae, chlorophyceae, cyanophyceae, crysophyceae, euglenoidea, trebouxlophyceae, mediophyceae, and nitachiaceae) and five classes of zooplanktons (maxillopoda, hexanuplia, copepoda, malacostraca, and oligotrichea). The density of plankton in Wonokromo, Dadapan and Juanda environments, was 37.64, 63.80, and 352.85 cells/L, respectively.

Comparative assessment of antibiotic susceptibility of coagulase-negative staphylococci in biofilm versus planktonic culture as assessed by bacterial enumeration or rapid XTT colorimetry.

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Cerca, Nuno; Martins, Silvia; Cerca, Filipe; Jefferson, Kimberly K; Pier, Gerald B; Oliveira, Rosário; Azeredo, Joana

2005-08-01

To quantitatively compare the antibiotic susceptibility of biofilms formed by the coagulase-negative staphylococci (CoNS) Staphylococcus epidermidis and Staphylococcus haemolyticus with the susceptibility of planktonic cultures. Several CoNS strains were grown planktonically or as biofilms to determine the effect of the mode of growth on the level of susceptibility to antibiotics with different mechanisms of action. The utility of a new, rapid colorimetric method that is based on the reduction of a tetrazolium salt (XTT) to measure cell viability was tested by comparison with standard bacterial enumeration techniques. A 6 h kinetic study was performed using dicloxacillin, cefazolin, vancomycin, tetracycline and rifampicin at the peak serum concentration of each antibiotic. In planktonic cells, inhibitors of cell wall synthesis were highly effective over a 3 h period. Biofilms were much less susceptible than planktonic cultures to all antibiotics tested, particularly inhibitors of cell wall synthesis. The susceptibility to inhibitors of protein and RNA synthesis was affected by the biofilm phenotype to a lesser degree. Standard bacterial enumeration techniques and the XTT method produced equivalent results both in biofilms and planktonic assays. This study provides a more accurate comparison between the antibiotic susceptibilities of planktonic versus biofilm populations, because the cell densities in the two populations were similar and because we measured the concentration required to inhibit bacterial metabolism rather than to eradicate the entire bacterial population. While the biofilm phenotype is highly resistant to antibiotics that target cell wall synthesis, it is fairly susceptible to antibiotics that target RNA and protein synthesis.

Prevalence of Colacium vesiculosum (Colaciales: Euglenophyceae on planktonic crustaceans in a subtropical shallow lake of Argentina

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Yolanda Zalocar

2011-09-01

Full Text Available Colacium vesiculosum (Euglenophyceae is an epibiont common on planktonic microcrustaceans of continental waters. The interaction between epibionts and substrate organisms is not very well known, particularly in subtropical environments of South America. In the present work, we analyzed the prevalence, density, biomass and attachment sites of C. vesiculosum on planktonic microcrustaceans from Paiva Lake, a subtropical lake of Argentina. With the aim to evaluate whether epibionts affect the filtering rates of Notodiaptomus spiniger, the dominant planktonic crustacean, we carried out bioassays using phytoplankton <53µm. Crustaceans were sampled using a PVC tube (1.2m long and 10cm in diameter, filtering 50L of water through a 53µm-mesh. Microcrustaceans were counted in Bogorov chambers under a stereoscopic microscope. The infested organisms were separated and observed with a photonic microscope to determine density and biovolume of epibionts, by analyzing their distribution on the exoskeleton. The prevalence of C. vesiculosum was higher in adult crustaceans than in their larvae and juveniles. The most infested group was that of calanoid copepods, related to their high density. The attachment sites on the exoskeleton were found to be the portions of the body which have a higher probability of encounter with epibionts during locomotion and feeding, i.e., antennae and thoracic legs in copepods, and thoracic legs and postabdomen in cladocerans. The similar values found in the filtering rate of infested and uninfested individuals of N. spiniger and the constant prevalence (<40% of epibiont algae, suggest that C. vesiculosum does not condition the life of planktonic crustaceans of Paiva Lake. Rev. Biol. Trop. 59 (3: 1295-1306. Epub 2011 September 01.

Differences in planktonic microbial communities associated with three types of macrophyte stands in a shallow lake.

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Mentes, Anikó; Szabó, Attila; Somogyi, Boglárka; Vajna, Balázs; Tugyi, Nóra; Csitári, Bianka; Vörös, Lajos; Felföldi, Tamás

2018-02-01

Little is known about how various substances from living and decomposing aquatic macrophytes affect the horizontal patterns of planktonic bacterial communities. Study sites were located within Lake Kolon, which is a freshwater marsh and can be characterised by open-water sites and small ponds with different macrovegetation (Phragmites australis, Nymphea alba and Utricularia vulgaris). Our aim was to reveal the impact of these macrophytes on the composition of the planktonic microbial communities using comparative analysis of environmental parameters, microscopy and pyrosequencing data. Bacterial 16S rRNA gene sequences were dominated by members of phyla Proteobacteria (36%-72%), Bacteroidetes (12%-33%) and Actinobacteria (5%-26%), but in the anoxic sample the ratio of Chlorobi (54%) was also remarkable. In the phytoplankton community, Cryptomonas sp., Dinobryon divergens, Euglena acus and chrysoflagellates had the highest proportion. Despite the similarities in most of the measured environmental parameters, the inner ponds had different bacterial and algal communities, suggesting that the presence and quality of macrophytes directly and indirectly controlled the composition of microbial plankton. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Antibacterial activities of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) against planktonic and biofilm growing Streptococcus mutans.

Science.gov (United States)

Sun, Mengjun; Dong, Jiachen; Xia, Yiru; Shu, Rong

2017-06-01

The aim of this study was to evaluate the potential antibacterial activities of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) against planktonic and biofilm modes of Streptococcus mutans (S. mutans). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The effects on planktonic growth and biofilm metabolic activity were evaluated by growth curve determination and MTT assay, respectively. Then, colony forming unit (CFU) counting, scanning electron microscopy (SEM) and real-time PCR were performed to further investigate the actions of DHA and EPA on exponential phase-S. mutans. Confocal laser scanning microscopy (CLSM) was used to detect the influences on mature biofilms. The MICs of DHA and EPA against S. mutans were 100 μM and 50 μM, respectively; the MBC of both compounds was 100 μM. In the presence of 12.5 μM-100 μM DHA or EPA, the planktonic growth and biofilm metabolic activity were reduced in varying degrees. For exponential-phase S. mutans, the viable counts, the bacterial membranes and the biofilm-associated gene expression were damaged by 100 μM DHA or EPA treatment. For 1-day-old biofilms, the thickness was decreased and the proportion of membrane-damaged bacteria was increased in the presence of 100 μM DHA or EPA. These results indicated that, DHA and EPA possessed antibacterial activities against planktonic and biofilm growing S. mutans. Copyright © 2017 Elsevier Ltd. All rights reserved.

Early detection monitoring for larval dreissenid mussels: how much plankton sampling is enough?

Science.gov (United States)

Counihan, Timothy D; Bollens, Stephen M

2017-03-01

The development of quagga and zebra mussel (dreissenids) monitoring programs in the Pacific Northwest provides a unique opportunity to evaluate a regional invasive species detection effort early in its development. Recent studies suggest that the ecological and economic costs of a dreissenid infestation in the Pacific Northwest of the USA would be significant. Consequently, efforts are underway to monitor for the presence of dreissenids. However, assessments of whether these efforts provide for early detection are lacking. We use information collected from 2012 to 2014 to characterize the development of larval dreissenid monitoring programs in the states of Idaho, Montana, Oregon, and Washington in the context of introduction and establishment risk. We also estimate the effort needed for high-probability detection of rare planktonic taxa in four Columbia and Snake River reservoirs and assess whether the current level of effort provides for early detection. We found that the effort expended to monitor for dreissenid mussels increased substantially from 2012 to 2014, that efforts were distributed across risk categories ranging from high to very low, and that substantial gaps in our knowledge of both introduction and establishment risk exist. The estimated volume of filtered water required to fully census planktonic taxa or to provide high-probability detection of rare taxa was high for the four reservoirs examined. We conclude that the current level of effort expended does not provide for high-probability detection of larval dreissenids or other planktonic taxa when they are rare in these reservoirs. We discuss options to improve early detection capabilities.

The Messinian/Early Pliocene transition in Eastern Mediterranean: New palaeoenvironmental data from the Kalamaki section (Zakynthos Island, Greece)

Science.gov (United States)

Drinia, Hara; Antonarakou, Assimina; Tsourou, Theodora; Tzortzaki, Evi; Filippidi, Amalia; Nikolaou, Konstantinos

2010-05-01

The purpose of this study is to describe the Miocene-Pliocene microfaunal development, and to discuss its palaeoenvironmental and palaeogeographical significance. The studied section (Kalamaki section) is located in the eastern part of Zakynthos Island (western Greece). Details on lithology and stratigraphy of the section are given in Dermitzakis (1978) and Nikolaou (1986). Planktonic species indicate that sediments span the interval which corresponds to MPL1 Zone (Zanclean, early Pliocene) which is in accordance with the biostratigraphic configuration of Rouchy et al. (1992) and Pierre et al. (2006). The studied interval is characterized by the Sphaeroidinellopsis Acme Zone and the presence of Globorotalia margaritae. The recognized succession of microfossil assemblages serves to interpret the evolution of some palaeoenvironmental factors (waterdepth, salinity and oxygen content), whereas the planktonic foraminiferal zonation allows an age assignment to the events. During the Late Messinian brackish conditions became dominant. The early Pliocene is characterized by a sudden return to well oxygenated, open marine, outer shelf conditions. At the basal part of the record, the high abundance of the 'shallow water component' of the benthic foraminiferal fauna indicates a well-vegetated environment with either normal marine salinity or a tendency to hyposalinity (e.g. Murray, 2006). Open marine conditions are indicated by the diversity of benthic and planktonic foraminifera. The abundance of Lenticulina spp., Cibicidoides pseudoungerianus, Planulina ariminensis, Pullenia, Gyroidina, and the virtual absence of Cibicidoides dutemplei and other typical shelf-taxa, suggest an upper bathyal waterdepth of 300-400 m (cf. Pujos, 1976; Jorissen, 1988). Partly, the abundance of Cibicidoides pseudoungerianus, Bulimina costata and Uvigerina peregrina reflect fluctuations in oxygen content of the bottom waters. However, extreme conditions were never reached during deposition. The

Prospective role of indigenous Exiguobacterium profundum PT2 in arsenic biotransformation and biosorption by planktonic cultures and biofilms.

Science.gov (United States)

Saba; Andreasen, R; Li, Y; Rehman, Y; Ahmed, M; Meyer, R L; Sabri, A N

2018-02-01

The aim of this study was to analyse arsenic (As) transformation and biosorption by indigenous As-resistant bacteria both in planktonic and biofilm modes of growth. As-resistant bacteria were isolated from industrial waste water and strain PT2, and identified as Exiguobacterium profundum through 16S rRNA gene sequencing was selected for further study. As transformation and biosorption by E. profundumPT2 was determined by HPLC-ICP-MS analysis. Planktonic cultures reduced 3·73 mmol l -1 As 5+ into As 3+ from artificial waste water effluent after 48-h incubation. In case of biosorption, planktonic cultures and biofilms exhibited 25·2 and 29·4 mg g -1 biomass biosorption, respectively. As biosorption kinetics followed Freundlich isotherm and pseudo second-order model. Biofilm formation peaked after 3 days of incubation, and in the presence of As stress, biofilm formation was significantly affected in contrast to control (P biofilms with an increased demand of nutrients was revealed by minimum roughness and maximum surface to biovolume ratio measured through CLSM analysis. Indigenous As-resistant E. profundumPT2 was found capable of As transformation and biosorption both in the form of planktonic cultures and biofilms. Indigenous biofilm forming E. profundum PT2 revealing As biosorption and biotransformation potential is presented an eco-friendly and cost-effective source for As remediation that can be implemented for waste water treatment. © 2017 The Society for Applied Microbiology.

Holocene record of benthic foraminiferal morphogroups from the ...

Indian Academy of Sciences (India)

35

The Arabian Sea is characterized today by a well-developed and perennial oxygen minimum. 15 ... inventory contributing to global climate change. 18 .... Water (ASW) and Persian Gulf Water (PGW) in the eastern Arabian Sea is less evident.

Influence of water mixing and food web status on the response of planktonic communities to enhanced ultraviolet-B radiation

Science.gov (United States)

Mostajir, B.; Uvbr Team

2003-04-01

Two series of mesocosm experiments were carried out in 1996 and 1997 using the natural planktonic assemblage, ultraviolet-B radiation (UVBR: 280-320 nm) at the community level. The water used in the first experiment was rich in nitrate (ca. 8-10 μM) and phytoplankton biomass (5 μg Chlorophyll a L-1: Chl a), conditions typical of an eutrophic coastal zone with herbivorous food web characteristics. In contrast, the water used in the second experiment was poor in nitrate (food web. Furthermore, to understand the influence of vertical mixing on the effects of UVBR on the planktonic community, two mixing regimes (fast and slow) were tested during the mesocosm experiments of 1997. The results showed that the mixing regime can moderate the effects of UVBR on the planktonic community and can also modify completely the species composition in the mesocosms much more than the UVBR. Comparison between the impact of UVBR on the planktonic community presented in these two experiments suggested that regenerated production-based systems (e.g. microbial food webs) tolerate the effects of UVBR more efficiently than do new production-based systems (herbivorous food webs). Results regarding the potential effects of UVBR in different marine systems, coastal versus oceanic, where different physical systems dominate, fast versus slow mixing, and consequently the development of different food webs are favored, herbivorous versus microbial, will be discussed.

Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

Directory of Open Access Journals (Sweden)

Lara S. eGarcia-Corral

2015-07-01

Full Text Available The Mediterranean Sea is a vulnerable region for climate change, warming at higher rates compare to the global ocean. Warming leads to increased stratification of the water column and enhanced the oligotrophic nature of the Mediterranean Sea. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely enhancing impacts to biota.Here we experimentally elucidate the cumulative effects of warming and natural UV-B radiation on the net community production (NCP of plankton communities. We conducted five experiments at monthly intervals, from June to October 2013, and evaluated the responses of NCP to ambient UV-B radiation and warming (+3ºC, alone and in combination, in a coastal area of the northwest Mediterranean Sea. UV-B radiation and warming lead to reduced net community production and resulted in a heterotrophic (NCP<0 metabolic balance. Both UV-B radiation and temperature, showed a significant individual effect in NCP across treatments and time. However, their joint effect showed to be synergistic as the interaction between them (UV x Temp was statistically significant in most of the experiments performed. Our results showed that both drivers, would affect the gas exchange of CO2-O2 from and to the atmosphere and the role of plankton communities in the Mediterranean carbon cycle

Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

KAUST Repository

Garcia-Corral, Lara S.

2015-07-07

The Mediterranean Sea is a vulnerable region for climate change, warming at higher rates compare to the global ocean. Warming leads to increased stratification of the water column and enhanced the oligotrophic nature of the Mediterranean Sea. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A) may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely enhancing impacts to biota. Here we experimentally elucidate the cumulative effects of warming and natural UV-B radiation on the net community production (NCP) of plankton communities. We conducted five experiments at monthly intervals, from June to October 2013, and evaluated the responses of NCP to ambient UV-B radiation and warming (+3°C), alone and in combination, in a coastal area of the northwest Mediterranean Sea. UV-B radiation and warming lead to reduced NCP and resulted in a heterotrophic (NCP < 0) metabolic balance. Both UV-B radiation and temperature, showed a significant individual effect in NCP across treatments and time. However, their joint effect showed to be synergistic as the interaction between them (UV × Temp) was statistically significant in most of the experiments performed. Our results showed that both drivers, would affect the gas exchange of CO2−O2 from and to the atmosphere and the role of plankton communities in the Mediterranean carbon cycle.

Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

KAUST Repository

Garcia-Corral, Lara S.; Martinez Ayala, Juan; Duarte, Carlos M.; Agusti, Susana

2015-01-01

. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A) may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely

Effects of the global changes on the aquatic ecosystems in West Europe - role of the plankton communities; Effets des changements globaux sur les ecosystemes aquatiques d'Europe Occidentale - role des communautes planctoniques

Energy Technology Data Exchange (ETDEWEB)

Souissi, S. [Universite des Sciences et Technologies de Lille, Ecosystem COmplexity REsearch Group, Station Marine de Wimereux, CNRS - FRE 2816 ELICO, 62 - Wimereux (France)

2007-07-01

Examination of long-term records of aquatic ecosystems has provided useful information to find out their major driving forces. Understanding the impact of climate change on these ecosystems, the management of their resources and the extrapolation between sites are the main scopes of actual and emerging studies. Such goals can be achieved by inter-site and inter-ecosystem comparisons. This approach was undertaken during our project which has the originality to tackle with marine and freshwater ecosystems. It allowed us to compile and validate several multi-decadal time series of planktonic and other physical driving forces at local and regional scales. Then, the same methodology based on the analysis of the variability of climate indices and biological data across several spatial scales was used. The different ecosystems analyzed here showed clear response to the North Atlantic climate variability. Although the local differences abrupt changes in community composition occurred in all ecosystems in the middle of the years 80. During this period there was also a major shift in climatic conditions during winter and early spring, suggesting an impact of climatic factors. Phenological changes were also observed in plankton communities in all sites. The consequences of the modifications of plankton dynamics on higher trophic levels were also showed. Fluctuations in plankton have resulted in long-term changes in cod recruitment in the North Sea (bottom-up control). On the other hand, both climate change and the improvement of trophic status in Geneva Lake favored the outbreak of whitefish during the years 90. Lower larval mortality and better recruitment are supposed to be linked to faster growth associated with warmer temperatures and better food conditions induced by better temporal overlap between larvae hatching and zooplankton development. (author)

Nutrient supply, surface currents, and plankton dynamics predict zooplankton hotspots in coastal upwelling systems

Science.gov (United States)

Messié, Monique; Chavez, Francisco P.

2017-09-01

A simple combination of wind-driven nutrient upwelling, surface currents, and plankton growth/grazing equations generates zooplankton patchiness and hotspots in coastal upwelling regions. Starting with an initial input of nitrate from coastal upwelling, growth and grazing equations evolve phytoplankton and zooplankton over time and space following surface currents. The model simulates the transition from coastal (large phytoplankton, e.g., diatoms) to offshore (picophytoplankton and microzooplankton) communities, and in between generates a large zooplankton maximum. The method was applied to four major upwelling systems (California, Peru, Northwest Africa, and Benguela) using latitudinal estimates of wind-driven nitrate supply and satellite-based surface currents. The resulting zooplankton simulations are patchy in nature; areas of high concentrations coincide with previously documented copepod and krill hotspots. The exercise highlights the importance of the upwelling process and surface currents in shaping plankton communities.

Precipitation and temperature drive seasonal variation in bioaccumulation of polycyclic aromatic hydrocarbons in the planktonic food webs of a subtropical shallow eutrophic lake in China.

Science.gov (United States)

Tao, Yuqiang; Yu, Jing; Xue, Bin; Yao, Shuchun; Wang, Sumin

2017-04-01

Hydrophobic organic contaminants (HOCs) are toxic and ubiquitous in aquatic environments and pose great risks to aquatic organisms. Bioaccumulation by plankton is the first step for HOCs to enter aquatic food webs. Trophic status is considered to dominate variations in bioaccumulation of HOCs in plankton in temperate and frigid deep oligotrophic waters. However, long-term driving factors for bioaccumulation of HOCs in planktonic food webs of subtropical shallow eutrophic waters have not been well investigated. China has the largest subtropical lake density in the Northern Hemisphere. Due to limited field data, long-term variations in the bioaccumulation of HOCs in these lakes are almost unknown. Here we take Lake Xuanwu as an example to investigate long-term variations in the bioaccumulation, and biomagnification of polycyclic aromatic hydrocarbon (PAHs) in planktonic food webs of subtropical shallow eutrophic lakes in China, and elucidate the driving factors. Our results indicate that temperature rather than nutrients dominates long-term dynamics of planktonic biomass in this lake. Precipitation significantly enhances the concentrations of the PAHs, and total suspended particles, and consequently affects the distribution of the PAHs in the water column. Biomass dilution induced by temperature dominates bioaccumulation of the PAHs by both phytoplankton and zooplankton (copepods and cladocerans). Biomagnification of the PAHs from phytoplankton to zooplankton is positively correlated with temperature. Our study suggests that temperature and precipitation drive long-term variations in the bioaccumulation of the PAHs in the planktonic food webs of this subtropical shallow eutrophic lake. Lake Xuanwu has a similar mean annual temperature, annual precipitation, sunshine duration, and nutrient levels as other subtropical shallow eutrophic lakes in China. This study may also help to understand the bioaccumulation of HOCs in planktonic food webs of other subtropical shallow

Onderzoek aan enkele groepen uit het plankton verzameld in het kader van “Cooperative Investigations in the Caribbean and Adjacent Regions” (Cicar-project)

NARCIS (Netherlands)

Troost, Dick G.

1973-01-01

In February 1970 plankton sampling has been started as a section of the “Cooperative Investigations in the Caribbean and Adjacent Regions” (CICAR-project). Sampling was executed by ornithologists on board the M.S. “Luymes”. Open plankton nets with meshes of 0.056 mm diam. were used for sampling

Estimates of zooplankton abundance and size distribution with the Optical Plankton Counter (OPC)

DEFF Research Database (Denmark)

Wieland, Kai; Petersen, D.; Schnack, D.

1997-01-01

The capability of the Optical Plankton Count er (OPC) to examine the abundance and size distribution of zooplankton was tested in Storfjorden, Norway, in June 1993. Selected material obtained from net sampling was measured with a laboratory version of the OPC and compared with microscope analysis...

The planktonic food web of the Bizerte lagoon (south-western Mediterranean) during summer: I. Spatial distribution under different anthropogenic pressures

OpenAIRE

Hlaili, A; Grami, B; Niquil, N; Gosselin, M; Hamel, D; Troussellier, Marc; Mabrouk, H

2008-01-01

The structure and the trophic interactions of the planktonic food web were investigated during summer 2004 in a coastal lagoon of southwestern Mediterranean Sea. Biomasses of planktonic components as well as bacterial and phytoplankton production and grazing by microzooplankton were quantified at four stations (MA, MB, MJ and R) inside the lagoon. Station MA was impacted by urban discharge, station MB was influenced by industrial activity, station MJ was located in a shellfish farming sector,...

Preliminary report on the study of benthic foraminiferal content in the marine sediment of Queen Maud Land Shelf, Lazarev Sea, Antarctic

Digital Repository Service at National Institute of Oceanography (India)

Sinha, R.; Nigam, R.; Khare, N.; Ingole, B.S.; Ghosh, D.N.

study of foraminiferal fauna has revealed a total number of seventeen genera as follows: Reophax Montfort, 1/808 Trochammina Jones and Parker, 1860 Sr. No. 1 2 3 4 5 6 7 8 Station No. P-3 P-5 P-6 P-7 P-8 P- 10 P- 11 P-13 Latitude (N) 12?53'17" 12...-asymmetrical forms are mainly represented by the Reophax, Marsipella, Rhabdammina and Sr. No. 1 2 3 4 5 Suborders Textulariina Lagenina Globigerinina Rotaliina Miliolina Total Super Families 06 01 01 03 01 12 Families 06 01 01 04 01 13 Genera 09 01 02 04 01 17 Fig. 2...

Inactivation kinetics of various chemical disinfectants on Aeromonas hydrophila planktonic cells and biofilms.

Science.gov (United States)

Jahid, Iqbal Kabir; Ha, Sang-Do

2014-05-01

The present article focuses on the inactivation kinetics of various disinfectants including ethanol, sodium hypochlorite, hydrogen peroxide, peracetic acid, and benzalkonium chloride against Aeromonas hydrophila biofilms and planktonic cells. Efficacy was determined by viable plate count and compared using a modified Weibull model. The removal of the biofilms matrix was determined by the crystal violet assay and was confirmed by field-emission scanning electron microscope. The results revealed that all the experimental data and calculated Weibull α (scale) and β (shape) parameters had a good fit, as the R(2) values were between 0.88 and 0.99. Biofilms are more resistant to disinfectants than planktonic cells. Ethanol (70%) was the most effective in killing cells in the biofilms and significantly reduced (preduction as well as the effectiveness of chemical disinfectants on biofilms. The study showed that the Weibull model could successfully be used on food and food contact surfaces to determine the exact contact time for killing biofilms-forming foodborne pathogens.

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

Geochemical record of anthropogenic impacts on Lake Valencia, Venezuela

International Nuclear Information System (INIS)

Xu Yunping; Jaffe, Rudolf

2009-01-01

Bulk geochemical parameters and organic matter biomarkers in a short, high resolution gravity core (Lake Valencia, Venezuela) were examined to reconstruct anthropogenic impacts on the lake's conditions. During the period of ca. 1840-1990, sedimentary organic matter was characterized by high contents of total organic C (TOC) and total N (TN), low TOC/TN values as well as relatively enriched δ 13 C and δ 15 N signals, suggesting a primary autochthonous (algae and macrophytes) organic matter origin. The occurrence of large amounts of C 23 and C 25 relative to C 29 and C 31 n-alkanes indicated substantial inputs from submerged/floating macrophytes. The variations of C 32 15-keto-ol, tetrahymanol, diploptene, C 32 bishomohopanol, 2-methylhopane, dinosterol and isoarborinol concentrations over the investigated period record changes in the planktonic community structure, including Botryococcus braunii, bacteriavore ciliates, cyanobacteria, Eustigmatophytes and dinoflagellates. A principal shift occurred in the 1910s when cyanobacteria and dinoflagellates became more abundant at the expense and decline of B. braunii and Eustigmatophytes, likely related to increasing anthropogenic activity around the lake. A second shift (less obvious) occurred in the 1960s when cyanobacteria became the sole predominant planktonic class, coinciding with further deterioration of lake conditions

A simple filtration method to remove plankton-associated Vibrio cholerae in raw water supplies in developing countries.

Science.gov (United States)

Huq, A; Xu, B; Chowdhury, M A; Islam, M S; Montilla, R; Colwell, R R

1996-07-01

Plankton to which cells of Vibrio cholerae O1 and/or O139 were attached was introduced into 0.5% Instant Ocean microcosms maintained at 25 degrees C. The bulk of the plankton and associated particulates was removed with a filter constructed from either nylon net and one of several different types of sari material, the latter being very inexpensive and readily available in villages in Bangladesh, where V. cholerae is endemic. V. cholerae was enumerated before and after filtration to evaluate the efficiency of the filtration procedure. The results obtained indicate that 99% of V. cholerae, i.e., those cells attached to plankton, were removed from the water samples. Epidemic strains of V. cholerae O1 and O139 from various geographical sources, including Bangladesh, Brazil, India, and Mexico, were included in the experiments. Removal of vibrios from water by this simple filtration method was found to yield consistent results with all strains examined in this study. Thus, it is concluded that a simple filtration procedure involving the use of domestic sari material can reduce the number of cholera vibrios attached to plankton in raw water from ponds and rivers commonly used for drinking. Since untreated water from such sources serves as drinking water for millions of people living in developing countries (e.g., Bangladesh), filtration should prove effective at reducing the incidence and severity of outbreaks, especially in places that lack fuel wood for boiling water and/or municipal water treatment plants. The results of this study provide the basis for determining such reductions, which are to be carried out in the near future.

SyPRID sampler: A large-volume, high-resolution, autonomous, deep-ocean precision plankton sampling system

Science.gov (United States)

Billings, Andrew; Kaiser, Carl; Young, Craig M.; Hiebert, Laurel S.; Cole, Eli; Wagner, Jamie K. S.; Van Dover, Cindy Lee

2017-03-01

The current standard for large-volume (thousands of cubic meters) zooplankton sampling in the deep sea is the MOCNESS, a system of multiple opening-closing nets, typically lowered to within 50 m of the seabed and towed obliquely to the surface to obtain low-spatial-resolution samples that integrate across 10 s of meters of water depth. The SyPRID (Sentry Precision Robotic Impeller Driven) sampler is an innovative, deep-rated (6000 m) plankton sampler that partners with the Sentry Autonomous Underwater Vehicle (AUV) to obtain paired, large-volume plankton samples at specified depths and survey lines to within 1.5 m of the seabed and with simultaneous collection of sensor data. SyPRID uses a perforated Ultra-High-Molecular-Weight (UHMW) plastic tube to support a fine mesh net within an outer carbon composite tube (tube-within-a-tube design), with an axial flow pump located aft of the capture filter. The pump facilitates flow through the system and reduces or possibly eliminates the bow wave at the mouth opening. The cod end, a hollow truncated cone, is also made of UHMW plastic and includes a collection volume designed to provide an area where zooplankton can collect, out of the high flow region. SyPRID attaches as a saddle-pack to the Sentry vehicle. Sentry itself is configured with a flight control system that enables autonomous survey paths to low altitudes. In its verification deployment at the Blake Ridge Seep (2160 m) on the US Atlantic Margin, SyPRID was operated for 6 h at an altitude of 5 m. It recovered plankton samples, including delicate living larvae, from the near-bottom stratum that is seldom sampled by a typical MOCNESS tow. The prototype SyPRID and its next generations will enable studies of plankton or other particulate distributions associated with localized physico-chemical strata in the water column or above patchy habitats on the seafloor.

Interacting growth and loss rates: The balance of top-down and bottom-up controls in plankton communities

International Nuclear Information System (INIS)

Lehman, J.T.

1991-01-01

Application of resource-based competition theory to high-nutrient, low-chlorophyll regions of the ocean suggests that single-factor controls on vertical export rates of carbon from euphotic zones are unlikely. High specific rates of grazing or sinking losses interact with growth physiology to produce nutrient requirements in situ that are much higher than those required for the growth of populations held in bottle bioassays. The efficiency of vertical export of carbon by sinking particulates can vary with species composition of the plankton, which in turn can be altered by nutrient manipulation. A simulation model explores possible changes to species composition and vertical carbon flux which might result from addition of Fe to Southern Ocean plankton communities. Nutrient manipulation permits invasion of plankton communities by taxa not originally present and does not necessarily increase the biomass or metabolism of resident species. This makes a priori prediction of fluxes associated with an enriched and altered community fundamentally uncertain if predictions are based on stoichiometries and physiologies of the original resident taxa. Vertical carbon flux could either increase or decrease in response to single-element addition, depending on the attributes of the invading species

Metals anomalies in foraminiferal shells as indicators for industrial pollution: a case study from the Mediterranean coast of Israel

Science.gov (United States)

Titelboim, Danna; Sadekov, Aleksey; Almogi-Labin, Ahuva; Herut, Barak; Kucera, Michal; Abramovich, Sigal

2017-04-01

In recent years we have been witnessing a considerable growth of industrial facilities along coastal areas. Some of these have major economical and national importance yet their operation can introduce a wide range of chemicals that might contaminate the coastal area and impact local ecosystems and our health. Among some of these harmful chemicals are metals that are introduced to the coastal environment by some of these facilities. Here we present a novel approach for monitoring low-level industrial pollution in coastal environments based on anomalies in metal concentration within foraminiferal shells. Living foraminifera are used as bio-indicators of the environmental status of any marine habitat. As unicellular organisms with short life and reproductive cycles, they are extremely sensitive to long and short-term changes. The majority of foraminifera precipitate CaCO3 (low-Mg-calcite, high-Mg calcite or rarely aragonite tests). Their calcareous shells are precipitated by a mechanism that involves direct seawater vacuolization which reflects the chemical composition of the ambient water. For this reason the geochemical composition of their shells is particularly applicable as a tool for marine environmental monitoring. Material for this study was obtained during the monthly campaigns of a biomonitoring project (2012-2015) of a heat polluted area and of a nearby natural clean station off the northern Mediterranean coast of Israel. Essentially, monitoring of water chemistry in both habitats showed no indications of presence of heavy metal contamination. Yet, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of two common local foraminifera the hyaline species Pararotalia calcariformata and the miliolid species Lachlanella sp. 1 that were collected alive from both areas, recorded presence of various metals (Mn, Cu, Zn, Ba, Pb) within their shells. Metal concentrations within the miliolid species were significantly higher than those of

Environmental modulation of the plankton community composition and size-structure along the eutrophic intertidal coast of the Río de la Plata estuary, Argentina

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Maximiliano D. Garcia

2014-05-01

Full Text Available In this study we investigated the spatial distribution of the plankton community, bacterio-, phyto- and zooplankton, in relation with environmental conditions along the intertidal coast of the Río de la Plata estuary, Argentina. Plankton was analyzed in terms of species composition, abundance, biomass (carbon content and size-structure. We aim to evaluate the potential effects of anthropogenic impacts (e.g., nutrient enrichment and physicochemical gradients alongshore (e.g., salinity, turbidity on the composition and functioning of the plankton. We asked whether the natural structuring of the plankton by salinity and turbidity, known to be true of estuaries, is modified by eutrophication along the studied shoreline. We found that the density and biomass of bacteria and phytoplankton were strikingly enhanced by high eutrophication levels along the intertidal southwest coast of the Río de la Plata estuary. We also found that the highest zooplankton density in the most polluted area but the biomass showed a different distribution pattern. Nevertheless, when zooplankton was analyzed by means of its size fraction, we accordingly found that the microzooplankton biomass was positively associated with smaller-size phytoplankton groups and the most polluted study sites. Copepods were the major taxonomic groups that best represented the mesozooplankton biomass. We therefore expected that its distribution was modulated by the presence of its food items (i.e., large cells which, in turn, were more abundant in the middle-outer zone. In contrast, we found that the highest biomass of copepods occurred at the innermost site of the estuary and we found no significant association with other planktonic groups. Overall, this study highlights the noteworthy impacts of human activities modifying the functioning of this coastal ecosystem. The differences found in the taxonomic composition and size structure of the planktonic community assemblage between the most

A Model of the Dynamics of Plankton Patchiness

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Wolfgang Ebenhöh

1980-04-01

Full Text Available A mathematical model of the dynamics of plankton patchiness in the intermediate scale (1 km-10 km was developed. Mechanisms that may be important in the creation and destruction of patches were selected and modelled. Such mechanisms are: horizontal turbulent diffusion, noise in the vertical turbulence, vertical migration of the zooplankton combined with a velocity profile and consumption of zooplankton by fish in schools. Patchiness is described by thc usc of the moments of density distributions, coherence lengths and correlations of phytoplankton and zooplankton. These parameters are investigated as functions of time and, also, for their dependence on the parameters of the patch creation mechanisms.

Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth.

Science.gov (United States)

Luef, Birgit; Fakra, Sirine C; Csencsits, Roseann; Wrighton, Kelly C; Williams, Kenneth H; Wilkins, Michael J; Downing, Kenneth H; Long, Philip E; Comolli, Luis R; Banfield, Jillian F

2013-02-01

Iron-reducing bacteria (FeRB) play key roles in anaerobic metal and carbon cycling and carry out biogeochemical transformations that can be harnessed for environmental bioremediation. A subset of FeRB require direct contact with Fe(III)-bearing minerals for dissimilatory growth, yet these bacteria must move between mineral particles. Furthermore, they proliferate in planktonic consortia during biostimulation experiments. Thus, a key question is how such organisms can sustain growth under these conditions. Here we characterized planktonic microbial communities sampled from an aquifer in Rifle, Colorado, USA, close to the peak of iron reduction following in situ acetate amendment. Samples were cryo-plunged on site and subsequently examined using correlated two- and three-dimensional cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission X-ray microscopy (STXM). The outer membranes of most cells were decorated with aggregates up to 150 nm in diameter composed of ∼3 nm wide amorphous, Fe-rich nanoparticles. Fluorescent in situ hybridization of lineage-specific probes applied to rRNA of cells subsequently imaged via cryo-TEM identified Geobacter spp., a well-studied group of FeRB. STXM results at the Fe L(2,3) absorption edges indicate that nanoparticle aggregates contain a variable mixture of Fe(II)-Fe(III), and are generally enriched in Fe(III). Geobacter bemidjiensis cultivated anaerobically in the laboratory on acetate and hydrous ferric oxyhydroxides also accumulated mixed-valence nanoparticle aggregates. In field-collected samples, FeRB with a wide variety of morphologies were associated with nano-aggregates, indicating that cell surface Fe(III) accumulation may be a general mechanism by which FeRB can grow while in planktonic suspension.

SAR11 Bacteria: The Most Abundant Plankton in the Oceans.

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Giovannoni, Stephen J

2017-01-03

SAR11 is a group of small, carbon-oxidizing bacteria that reach a global estimated population size of 2.4×10 28 cells-approximately 25% of all plankton. They are found throughout the oceans but reach their largest numbers in stratified, oligotrophic gyres, which are an expanding habitat in the warming oceans. SAR11 likely had a Precambrian origin and, over geological time, evolved into the niche of harvesting labile, low-molecular-weight dissolved organic matter (DOM). SAR11 cells are minimal in size and complexity, a phenomenon known as streamlining that is thought to benefit them by lowering the material costs of replication and maximizing transport functions that are essential to competition at ultralow nutrient concentrations. One of the surprises in SAR11 metabolism is their ability to both oxidize and produce a variety of volatile organic compounds that can diffuse into the atmosphere. SAR11 cells divide slowly and lack many forms of regulation commonly used by bacterial cells to adjust to changing environmental conditions. As a result of genome reduction, they require an unusual range of nutrients, which leads to complex biochemical interactions with other plankton. The study of SAR11 is providing insight into the biogeochemistry of labile DOM and is affecting microbiology beyond marine science by providing a model for understanding the evolution and function of streamlined cells.

Drivers of Plankton Patch Formation, Persistence and Decline in East Sound, Orcas Island, Washington

Science.gov (United States)

2012-09-30

Population dynamics of the marine planktonic ciliate Strombidinopsis multiauris: its potential to control phytoplankton blooms . Aquat. Microb. Ecol., 20...radii with patch exploitation in the coastal ocean. 5th International Zooplankton Production Symposium. Pucón, Chile Menden-Deuer S & Harvey* EL

Fate and effects of the insecticide chlorpyrifos in outdoor plankton-dominated microcosms in Thailand.

NARCIS (Netherlands)

Daam, M.A.; Crum, S.J.H.; Brink, van den P.J.; Nogueira, A.J.A.

2008-01-01

The fate and effects of the insecticide chlorpyrifos were studied in plankton-dominated, freshwater microcosms in Thailand. Disappearance rates of chlorpyrifos from the water column in the present study were similar to those in temperate regions. Insecticide accumulation in the sediment was

Effect of chlorine on Mycobacterium gordonae and Mycobacterium chubuense in planktonic and Biofilm State

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Alejandra Soledad Oriani

2018-01-01

Full Text Available Background: There is evidence that drinking water could be a source of infections with pathogenic nontuberculous mycobacteria (NTM potentially risky to human health. The aim was to investigate the resistance of two NTM isolated from drinking water, Mycobacterium gordonae and Mycobacterium chubuense, at different concentrations of chlorine (as sodium hypochlorite, used in drinking water sanitation. Methods: The NTM were grown in suspension and in biofilms and were challenged with biocide for 10 and 60 min. Results: To obtain 7-log reduction from the initial population of M. chubuense, in the planktonic state, there were necessary 20 ppm of chorine and 60 min of exposure. The same effect was achieved in M. gordonae with 10 ppm for the same period. The maximum reduction of both NTM in biofilm was 3-log reduction and was achieved using 30 ppm for 60 min. The chlorine susceptibility of cells in biofilms was significantly lower than that of planktonic cells. The results highlight the resistance of both NTM to the concentrations used in routine water sanitation (0.2 ppm according to Argentine Food Code. Differences in chlorine resistance found between the two NTM in planktonic growth decrease when they are grown in biofilm. Conclusion: This suggests that current water disinfection procedures do not always achieve effective control of NTM in the public supply system, with the consequent health risk to susceptible population, and the need to take into account biofilms, because of their deep consequences in the way to analyze the survival of prokaryotic cells in different environments.

New perspectives on the functioning and evolution of photosymbiosis in plankton: Mutualism or parasitism?

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Decelle, Johan

2013-07-01

Photosymbiosis is common and widely distributed in plankton and is considered to be beneficial for both partners (mutualism). Such intimate associations involving heterotrophic hosts and microalgal symbionts have been extensively studied in coral reefs, but in the planktonic realm, the ecology and evolution of photosymbioses remain poorly understood. Acantharia (Radiolaria) are ubiquitous and abundant heterotrophic marine protists, many of which host endosymbiotic microalgae. Two types of photosymbiosis involving acantharians have recently been described using molecular techniques: one found in a single acantharian species involving multiple microalgal partners (dinoflagellates and haptophytes), and the other observed in more than 25 acantharian species exclusively living with the haptophyte Phaeocystis. Contrary to most benthic and terrestrial mutualistic symbioses, these symbiotic associations share the common feature of involving symbionts that are abundant in their free-living stage. We propose a hypothetical framework that may explain this original mode of symbiosis, and discuss the ecological and evolutionary implications. We suggest that photosymbiosis in Acantharia, and probably in other planktonic hosts, may not be a mutualistic relationship but rather an "inverted parasitism," from which only hosts seem to benefit by sequestrating and exploiting microalgal cells. The relatively small population size of microalgae in hospite would prevent reciprocal evolution that can select uncooperative symbionts, therefore making this horizontally-transmitted association stable over evolutionary time. The more we learn about the diversity of life and the structure of genomes, the more it appears that much of the evolution of biodiversity is about the manipulation of other species-to gain resources and, in turn, to avoid being manipulated (John Thompson, 1999).

Effect of ocean acidification on the fatty acid composition of a natural plankton community

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Leu, E.; Daase, M.; Schulz, K. G.; Stuhr, A.; Riebesell, U.

2013-02-01

The effect of ocean acidification on the fatty acid composition of a natural plankton community in the Arctic was studied in a large-scale mesocosm experiment, carried out in Kongsfjorden (Svalbard, Norway) at 79° N. Nine mesocosms of ~50 m3 each were exposed to 8 different pCO2 levels (from natural background conditions to ~1420 μatm), yielding pH values (on the total scale) from ~8.3 to 7.5. Inorganic nutrients were added on day 13. The phytoplankton development during this 30-day experiment passed three distinct phases: (1) prior to the addition of inorganic nutrients, (2) first bloom after nutrient addition, and (3) second bloom after nutrient addition. The fatty acid composition of the natural plankton community was analysed and showed, in general, high percentages of polyunsaturated fatty acids (PUFAs): 44-60% of total fatty acids. Positive correlations with pCO2 were found for most PUFAs during phases 2 and/or 3, with the exception of 20:5n3 (eicosapentaenoic acid, EPA), an important diatom marker. These correlations are probably linked to changes in taxonomic composition in response to pCO2. While diatoms (together with prasinophytes and haptophytes) increased during phase 3 mainly in the low and intermediate pCO2 treatments, dinoflagellates were favoured by high CO2 concentrations during the same time period. This is reflected in the development of group-specific fatty acid trophic markers. No indications were found for a generally detrimental effect of ocean acidification on the planktonic food quality in terms of essential fatty acids.

Estimating cyclopoid copepod species richness and geographical distribution (Crustacea across a large hydrographical basin: comparing between samples from water column (plankton and macrophyte stands

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Gilmar Perbiche-Neves

2014-06-01

Full Text Available Species richness and geographical distribution of Cyclopoida freshwater copepods were analyzed along the "La Plata" River basin. Ninety-six samples were taken from 24 sampling sites, twelve sites for zooplankton in open waters and twelve sites for zooplankton within macrophyte stands, including reservoirs and lotic stretches. There were, on average, three species per sample in the plankton compared to five per sample in macrophytes. Six species were exclusive to the plankton, 10 to macrophyte stands, and 17 were common to both. Only one species was found in similar proportions in plankton and macrophytes, while five species were widely found in plankton, and thirteen in macrophytes. The distinction between species from open water zooplankton and macrophytes was supported by nonmetric multidimensional analysis. There was no distinct pattern of endemicity within the basin, and double sampling contributes to this result. This lack of sub-regional faunal differentiation is in accordance with other studies that have shown that cyclopoids generally have wide geographical distribution in the Neotropics and that some species there are cosmopolitan. This contrasts with other freshwater copepods such as Calanoida and some Harpacticoida. We conclude that sampling plankton and macrophytes together provided a more accurate estimate of the richness and geographical distribution of these organisms than sampling in either one of those zones alone.

The trophic role and impact of plankton ciliates in the microbial web structure of a tropical polymictic lake dominated by filamentous cyanobacteria

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Alfonso Esquivel

2016-03-01

Full Text Available The recent interest in the plankton structures and dynamics in tropical and subtropical lakes has revealed important trends that set these lakes apart from temperate lakes, and one of the main differences is the enhanced importance of the microbial food web with respect to net plankton. Ciliates are a key component of subtropical and tropical microbial webs because of their role as dominant picoplankton grazers and their ability to channel picoplankton production to the uppermost trophic levels. Plankton ciliates have been found to play a crucial role in the survival of fish larvae in lakes that share several features with Lake Catemaco, a eutrophic tropical Mexican lake. Therefore, the plankton ciliate composition, abundance, and biomass of Lake Catemaco were studied to assess their role in the microbial food web. The data were obtained from surface and bottom water samples collected at eleven points during three surveys in 2011 and an additional survey in 2013, with the surveys covering the local climatic seasons. The most abundant components of the plankton ciliate assemblages were small prostomatids (Urotricha spp., choreotrichs (Rimostrombidium spp., cyclotrichs (Mesodinium and Askenasia, and scuticociliates (Cyclidium, Cinetochilum, Pleuronema, and Uronema. Other important ciliates in terms of abundance and/or biomass were haptorids (Actinobolina, Belonophrya, Monodinium, Paradileptus, and Laginophrya, Halteria, oligotrichs (Limnostrombidium and Pelagostrombidium, Linostomella, Bursaridium, Cyrtolophosis, and Litonotus. The ciliate abundance averaged 57 cells mL-1 and ranged from 14 to 113 cells mL-1. The mean ciliate biomass was 71 µg C L-1 and ranged from 10 to 202 µg C L-1. Differences were not detected in ciliate abundance or biomass between the sampling points or sampling depths (surface to bottom; however, significant differences were observed between seasons for both variables. Nano-sized filamentous cyanobacteria were the most

Efficiency of phenol biodegradation by planktonic Pseudomonas pseudoalcaligenes (a constructed wetland isolate) vs. root and gravel biofilm.

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Kurzbaum, Eyal; Kirzhner, Felix; Sela, Shlomo; Zimmels, Yoram; Armon, Robert

2010-09-01

In the last two decades, constructed wetland systems gained increasing interest in wastewater treatment and as such have been intensively studied around the world. While most of the studies showed excellent removal of various pollutants, the exact contribution, in kinetic terms, of its particular components (such as: root, gravel and water) combined with bacteria is almost nonexistent. In the present study, a phenol degrader bacterium identified as Pseudomonas pseudoalcaligenes was isolated from a constructed wetland, and used in an experimental set-up containing: plants and gravel. Phenol removal rate by planktonic and biofilm bacteria (on sterile Zea mays roots and gravel surfaces) was studied. Specific phenol removal rates revealed significant advantage of planktonic cells (1.04 × 10(-9) mg phenol/CFU/h) compared to root and gravel biofilms: 4.59 × 10(-11)-2.04 × 10(-10) and 8.04 × 10(-11)-4.39 × 10(-10) (mg phenol/CFU/h), respectively. In batch cultures, phenol biodegradation kinetic parameters were determined by biomass growth rates and phenol removal as a function of time. Based on Haldane equation, kinetic constants such as μ(max) = 1.15/h, K(s) = 35.4 mg/L and K(i) = 198.6 mg/L fit well phenol removal by P. pseudoalcaligenes. Although P. pseudoalcaligenes planktonic cells showed the highest phenol removal rate, in constructed wetland systems and especially in those with sub-surface flow, it is expected that surface associated microorganisms (biofilms) will provide a much higher contribution in phenol and other organics removal, due to greater bacterial biomass. Factors affecting the performance of planktonic vs. biofilm bacteria in sub-surface flow constructed wetlands are further discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

Incorporation of inorganic mercury (Hg2+) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: The role of different plankton size fractions and species assemblages

International Nuclear Information System (INIS)

Soto Cárdenas, Carolina; Diéguez, Maria C.; Ribeiro Guevara, Sergio; Marvin-DiPasquale, Mark; Queimaliños, Claudia P.

2014-01-01

In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg 2+ ) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg 2+ by four plankton fractions (picoplankton: 0.2–2.7 μm; pico + nanoplankton: 0.2–20 μm; microplankton: 20–50 μm; and mesoplankton: 50–200 μm) obtained from four Andean Patagonian lakes, using the radioisotope 197 Hg 2+ . Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg 2+ in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico + nanoplankton play a central role leading the incorporation of Hg 2+ in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg 2+ by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria–nanoflagellates–crustaceans; bacteria–ciliates–crustaceans; endosymbiotic algae–ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg 2+ observed in all the plankton fractions. - Highlights: • Hg 2+ incorporation in lake plankton fractions was studied using the isotope 197 Hg 2+ . • Hg 2+ incorporation was assessed using three different

In Vitro Evaluation of Planktonic Growth on Experimental Cement-Retained Titanium Surfaces

Science.gov (United States)

Balci, Nur; Cakan, Umut; Aksu, Burak; Akgul, Oncu; Ulger, Nurver

2016-01-01

Background The purpose of this study was to compare the effects of selected cements, or their combination with titanium, on the growth of two periodontopathic bacteria: Prevotella intermedia (Pi) and Fusobacterium nucleatum (Fn). Material/Methods This study was comprised of several experimental groups: 1) Dental luting cements (glass ionomer cement, methacrylate-based resin cement, zinc-oxide eugenol cement, eugenol-free zinc oxide cement; 2) titanium discs; and 3) titanium combination cement discs. The disks were submerged in bacterial suspensions of either Fn or Pi. Planktonic bacterial growth within the test media was measured by determining the optical density of the cultures (OD600). Mean and standard deviations were calculated for planktonic growth from three separate experiments. Results Intergroup comparison of all experimental groups revealed increased growth of Pi associated with cement-titanium specimens in comparison with cement specimens. Regarding the comparison of all groups for Fn, there was an increased amount of bacterial growth in cement-titanium specimens although the increase was not statistically significant. Conclusions The combination of cement with titanium may exacerbate the bacterial growth capacity of Pi and Fn in contrast to their sole effect. PMID:27058704

In Vitro Evaluation of Planktonic Growth on Experimental Cement-Retained Titanium Surfaces.

Science.gov (United States)

Balci, Nur; Cakan, Umut; Aksu, Burak; Akgul, Oncu; Ulger, Nurver

2016-04-08

BACKGROUND The purpose of this study was to compare the effects of selected cements, or their combination with titanium, on the growth of two periodontopathic bacteria: Prevotella intermedia (Pi) and Fusobacterium nucleatum (Fn). MATERIAL AND METHODS This study was comprised of several experimental groups: 1) Dental luting cements (glass ionomer cement, methacrylate-based resin cement, zinc-oxide eugenol cement, eugenol-free zinc oxide cement; 2) titanium discs; and 3) titanium combination cement discs. The disks were submerged in bacterial suspensions of either Fn or Pi. Planktonic bacterial growth within the test media was measured by determining the optical density of the cultures (OD600). Mean and standard deviations were calculated for planktonic growth from three separate experiments. RESULTS Intergroup comparison of all experimental groups revealed increased growth of Pi associated with cement-titanium specimens in comparison with cement specimens. Regarding the comparison of all groups for Fn, there was an increased amount of bacterial growth in cement-titanium specimens although the increase was not statistically significant. CONCLUSIONS The combination of cement with titanium may exacerbate the bacterial growth capacity of Pi and Fn in contrast to their sole effect.

Effects of toxic cyanobacteria on plankton assemblage : community development during decay of Nodularia spumigena

DEFF Research Database (Denmark)

Engström-Öst, J.; Koski, Marja; Schmidt, K.

2002-01-01

We studied the development of the plankton community in an artificially created toxic Nodularia spumigena bloom during a 2 wk enclosure study at the SW coast of Finland in the Baltic Sea. We measured bacterial abundance, dominant phytoplankton groups and ciliates, as well as concentrations of phy...

Planktonic food web structure at a coastal time-series site: I. Partitioning of microbial abundances and carbon biomass

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Caron, David A.; Connell, Paige E.; Schaffner, Rebecca A.; Schnetzer, Astrid; Fuhrman, Jed A.; Countway, Peter D.; Kim, Diane Y.

2017-03-01

Biogeochemistry in marine plankton communities is strongly influenced by the activities of microbial species. Understanding the composition and dynamics of these assemblages is essential for modeling emergent community-level processes, yet few studies have examined all of the biological assemblages present in the plankton, and benchmark data of this sort from time-series studies are rare. Abundance and biomass of the entire microbial assemblage and mesozooplankton (>200 μm) were determined vertically, monthly and seasonally over a 3-year period at a coastal time-series station in the San Pedro Basin off the southwestern coast of the USA. All compartments of the planktonic community were enumerated (viruses in the femtoplankton size range [0.02-0.2 μm], bacteria + archaea and cyanobacteria in the picoplankton size range [0.2-2.0 μm], phototrophic and heterotrophic protists in the nanoplanktonic [2-20 μm] and microplanktonic [20-200 μm] size ranges, and mesozooplankton [>200 μm]. Carbon biomass of each category was estimated using standard conversion factors. Plankton abundances varied over seven orders of magnitude across all categories, and total carbon biomass averaged approximately 60 μg C l-1 in surface waters of the 890 m water column over the study period. Bacteria + archaea comprised the single largest component of biomass (>1/3 of the total), with the sum of phototrophic protistan biomass making up a similar proportion. Temporal variability at this subtropical station was not dramatic. Monthly depth-specific and depth-integrated biomass varied 2-fold at the station, while seasonal variances were generally web structure and function at this coastal observatory.

Outpacing the Anthropocene: New Constraints for the Rate of Carbon Release at the Paleocene-Eocene Thermal Maximum

Science.gov (United States)

Wright, J. D.; Schaller, M. F.

2012-12-01

The Paleocene/Eocene Thermal Maximum (PETM) Carbon Isotope Excursion (CIE) is linked to benthic foraminiferal extinction and excursion taxa in planktonic foraminifera and calcareous nannofossils. Previous studies have used integrated bio-magneto-stratigraphies, cycle counting, and extraterrestrial 3He accumulation rates to produce a range of estimates for the duration of the initial onset of the PETM CIE between 750 years to 30 kyr. Durations for the total release time (onset to initiation of recovery) range from 45 to 95 kyr. Uncertainty in the timing of the onset of the PETM CIE prevents the identification of a causal mechanism, and hence understanding the biological responses. Recent work on the Paleocene/Eocene Marlboro Clay has unveiled the presence of regular couplets (~2 cm) expressed in multiple cores and exposures throughout the Atlantic Coastal Plain. Specifically, the Millville and newly recovered Wilson Lake B cores contain 750 and 660 layers through the CIE, respectively. These couplets have corresponding oxygen stable isotope cycles, arguing for a climatic origin. Orbital and millennial periodicities are far too long to explain the ~750 layers identified in the Millville core. Seasonal insolation is the only regular climate cycle that can plausibly account for the observed δ18O amplitudes (~1‰, with some cycles up to 2‰) and layer counts. Seasonal freshwater input can also augment the cyclic oscillations in δ18O, but the majority of the variability is most plausibly ascribed to temperature. Wilson Lake B and Millville have total δ13C excursions of -5 and -4.5‰ respectively, as well as highly expanded sections of the PETM CIE. In the Millville core, high-resolution, bulk stable isotope records show a 3.5‰ δ13C decrease over 12 layers across the PETM CIE onset. Concomitant with this δ13C decrease is a sharp drop in CaCO3. Decreases in both proxies require a large, sudden release of isotopically light carbon. The couplet chronology indicates

Role of Delay on Planktonic Ecosystem in the Presence of a Toxic Producing Phytoplankton

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Swati Khare

2011-01-01

Full Text Available A mathematical model is proposed to study the role of distributed delay on plankton ecosystem in the presence of a toxic producing phytoplankton. The model includes three state variables, namely, nutrient concentration, phytoplankton biomass, and zooplankton biomass. The release of toxic substance by phytoplankton species reduces the growth of zooplankton and this plays an important role in plankton dynamics. In this paper, we introduce a delay (time-lag in the digestion of nutrient by phytoplankton. The stability analysis of all the feasible equilibria are studied and the existence of Hopf-bifurcation for the interior equilibrium of the system is explored. From the above analysis, we observe that the supply rate of nutrient and delay parameter play important role in changing the dynamical behaviour of the underlying system. Further, we have derived the explicit algorithm which determines the direction and the stability of Hopf-bifurcation solution. Finally, numerical simulation is carried out to support the theoretical result.

In vitro activity of azole derivatives and griseofulvin against planktonic and biofilm growth of clinical isolates of dermatophytes.

Science.gov (United States)

Brilhante, Raimunda Sâmia Nogueira; Correia, Edmilson Emanuel Monteiro; Guedes, Glaucia Morgana de Melo; de Oliveira, Jonathas Sales; Castelo-Branco, Débora de Souza Collares Maia; Cordeiro, Rossana de Aguiar; Pinheiro, Adriana de Queiroz; Chaves, Lúcio Jackson Queiroz; Pereira Neto, Waldemiro de Aquino; Sidrim, José Júlio Costa; Rocha, Marcos Fábio Gadelha

2018-03-08

As shown by recent research, most of the clinically relevant fungi, including dermatophytes, form biofilms in vitro and in vivo, which may exhibit antimicrobial tolerance that favour recurrent infections. The aim of this study was to determine the minimum inhibitory concentrations (MICs) of itraconazole (ITC), voriconazole (VCZ) and griseofulvin (GRI) against Trichophyton rubrum, Trichophyton tonsurans, Trichophyton mentagrophytes, Microsporum canis and Microsporum gypseum in planktonic and biofilm growth. For the planktonic form, susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI), document M38-A2, while biofilm susceptibility was evaluated using the XTT colorimetric essay. The planktonic growth of all strains was inhibited, with MIC values ranging from 0.00195 to 0.1225 μg/mL for VRC, 0.00195 to 0.25 μg/mL for ITC and GRI, while a 50-fold increase in the MIC was required to significantly reduce the metabolic activity (P < .05) of dermatophyte biofilms. In brief, the ability of dermatophytes to form biofilms may be a contributing factor for the recalcitrance of dermatophytoses or the dissemination of the disease. © 2018 Blackwell Verlag GmbH.

The novel oral glucan synthase inhibitor SCY-078 shows in vitro activity against sessile and planktonic Candida spp.

Science.gov (United States)

Marcos-Zambrano, Laura Judith; Gómez-Perosanz, Marta; Escribano, Pilar; Bouza, Emilio; Guinea, Jesús

2017-07-01

We studied the antifungal activity of SCY-078 (an orally bioavailable 1,3-β -d- glucan synthesis inhibitor), micafungin and fluconazole against the planktonic and sessile forms of 178 Candida and non- Candida isolates causing fungaemia in patients recently admitted to a large European hospital. The in vitro activity of SCY-078, micafungin and fluconazole against the planktonic form of the isolates was assessed using EUCAST EDef 7.3 and CLSI M27-A3. Antibiofilm activity was assessed using the XTT reduction assay. SCY-078 and micafungin showed potent in vitro activity against Candida and non- Candida isolates. The in vitro activity of both drugs was similar, but SYC-078 displayed significantly lower MIC values than micafungin against Candida parapsilosis and non- Candida isolates, whereas micafungin displayed significantly lower MIC values for the remaining species ( P  Candida glabrata , in which the micafungin sessile MIC values were significantly lower ( P  Candida isolates in both sessile and planktonic forms is comparable to that of micafungin. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Late Quaternary high resolution micropaleontological and sedimentological records in the Gulf of Cadiz.

Science.gov (United States)

Balestra, B.; Ducassou, E.; Zarikian, C.; Bout-Roumazeilles, V.; Flores, J. A.; Paytan, A.

2017-12-01

We present preliminary micropaleontological and sedimentological data from IODP Site U1390 (Expedition 339), located in the central middle slope of the Gulf of Cadiz, since the last glaciation. This site has been targeted for reconstruction of regional paleo-circulation as it shows particularly high sedimentation rates, throughout the Holocene and the Last Glacial Maximum (LGM). We use micropaleontological and sedimentological proxies to understand the bottom current variations through time and the ecological conditions at the sea surface (planktonic foraminifer, pteropod and nannofossil assemblages), and the sea bottom (ostracod assemblages). Eleven samples, chosen at transitions of planktonic foraminifer assemblages, have been dated by AMS radiocarbon analyses. Preliminary results from benthic ostracod assemblages show variations in bottom water ventilation and food supply. Planktonic foraminifer assemblages clearly show the well-known cold events of this period such as the Younger Dryas and Heinrich stadial associated to coarser sediment, and warmer phases such as the Bölling-Allerød associated to muddy sediment. Other bio-events within the Holocene period are also recorded. The preservation of the coccolithophore assemblages is good to moderate. Coccolith abundances (expressed in coccoliths/gr of sediment) show higher values during the Holocene and generally are like assemblages previously reported for the same area. Implications for characterization of the Holocene, the last termination and LGM ecological conditions at high resolution and their potential fluctuations (i.e. amplitude and magnitude) under the influence of the lower core of the Mediterranean Outflow Water (MOW), with this multi proxy approach based on sedimentological, and paleontological data will be discussed.

60Co accumulation from sediment and planktonic algae by midge larvae (Chironomus luridus)

International Nuclear Information System (INIS)

Baudin, J.P.; Nucho, R.

1992-01-01

This paper reports the results of several experiments carried out to evaluate uptake and retention by a limicolous midge larva of 60 Co retained in sediment, either adsorbed on mineral particles or bound to planktonic algae. In order to determine their relative contributions in radionuclide accumulation, the different vectors (water, algae and sediment) were first labelled individually and then simultaneously. 60 Co accumulation from water and from algae results in a maximum concentration factor of 30 and in a mean trophic transfer factor of 4·5 × 10 −3 . The level of contamination of midge larvae from sediment is markedly influenced by the presence of endogenous organic matter. Thus the radionuclide transfer factor is about twice as high for larvae placed in labelled raw sediment than for larvae placed in labelled incinerated sediment, in the presence as in the absence of contaminated planktonic algae. Irrespective of the contamination conditions, 60 Co depuration from midge larvae is a very rapid phenomenon that corresponds, in all cases, to a radionuclide half-life of only a few days

60Co accumulation from sediment and planktonic algae by midge larvae (Chironomus luridus)

International Nuclear Information System (INIS)

Baudin, J.P.; Nucho, R.

1992-01-01

This paper reports the results of several experiments carried out to evaluate uptake and retention by a limicolous midge larva of 60 Co retained in sediment, either adsorbed on mineral particles or bound to planktonic algae. In order to determine their relative contributions in radionuclide accumulation, the different vectors (water, algae and sediment) were first labelled individually and then simultaneously. 60 Co accumulation from water and from algae results in a maximum concentration factor of 30 and in a mean trophic transfer factor of 4.5 x 10 -3 . The level of contamination of midge larvae from sediment is markedly influenced by the presence of endogenous organic matter. Thus the radionuclide transfer factor is about twice as high for larvae placed in labelled raw sediment than for larvae placed in labelled incinerated sediment, in the presence as in the absence of contaminated planktonic algae. Irrespective of the contamination conditions, 60 Co depuration from midge larvae is a very rapid phenomenon that corresponds, in all cases, to a radionuclide half-life of only a few days. (author)

Standing out from the crowd: Spotting your targets in a mixed plankton sample.

Science.gov (United States)

Harada, Alice E; Burton, Ronald S

2017-11-01

The diversity of marine organisms is staggering, and this fact is readily appreciated by microscopic examination of the contents of a plankton net after a short tow across the ocean surface. Although this diversity is beautiful, it can present a significant problem for those seeking to extract information about a single species of interest. Enumeration of the eggs and larvae of a specific target species can provide a quantitative window into reproductive dynamics that are of great use for fisheries stock assessment and management. But how do you efficiently sort through the mass of plankton and identify target species' eggs and larvae that may be morphologically indistinguishable from those of a number of other local species? In this issue of Molecular Ecology Resources, Oxley et al. () describe an innovative in situ hybridization (ISH) approach that successfully solves this important problem and opens an exciting new avenue to ichthyoplankton analysis that may be widely adopted by both fish ecologists and fisheries managers. © 2017 John Wiley & Sons Ltd.

Community barcoding reveals little effect of ocean acidification on the composition of coastal plankton communities: Evidence from a long-term mesocosm study in the Gullmar Fjord, Skagerrak.

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Julia A F Langer

Full Text Available The acidification of the oceans could potentially alter marine plankton communities with consequences for ecosystem functioning. While several studies have investigated effects of ocean acidification on communities using traditional methods, few have used genetic analyses. Here, we use community barcoding to assess the impact of ocean acidification on the composition of a coastal plankton community in a large scale, in situ, long-term mesocosm experiment. High-throughput sequencing resulted in the identification of a wide range of planktonic taxa (Alveolata, Cryptophyta, Haptophyceae, Fungi, Metazoa, Hydrozoa, Rhizaria, Straminipila, Chlorophyta. Analyses based on predicted operational taxonomical units as well as taxonomical compositions revealed no differences between communities in high CO2 mesocosms (~ 760 μatm and those exposed to present-day CO2 conditions. Observed shifts in the planktonic community composition were mainly related to seasonal changes in temperature and nutrients. Furthermore, based on our investigations, the elevated CO2 did not affect the intraspecific diversity of the most common mesozooplankter, the calanoid copepod Pseudocalanus acuspes. Nevertheless, accompanying studies found temporary effects attributed to a raise in CO2. Differences in taxa composition between the CO2 treatments could, however, only be observed in a specific period of the experiment. Based on our genetic investigations, no compositional long-term shifts of the plankton communities exposed to elevated CO2 conditions were observed. Thus, we conclude that the compositions of planktonic communities, especially those in coastal areas, remain rather unaffected by increased CO2.

Community barcoding reveals little effect of ocean acidification on the composition of coastal plankton communities: Evidence from a long-term mesocosm study in the Gullmar Fjord, Skagerrak.

Science.gov (United States)

Langer, Julia A F; Sharma, Rahul; Schmidt, Susanne I; Bahrdt, Sebastian; Horn, Henriette G; Algueró-Muñiz, María; Nam, Bora; Achterberg, Eric P; Riebesell, Ulf; Boersma, Maarten; Thines, Marco; Schwenk, Klaus

2017-01-01

The acidification of the oceans could potentially alter marine plankton communities with consequences for ecosystem functioning. While several studies have investigated effects of ocean acidification on communities using traditional methods, few have used genetic analyses. Here, we use community barcoding to assess the impact of ocean acidification on the composition of a coastal plankton community in a large scale, in situ, long-term mesocosm experiment. High-throughput sequencing resulted in the identification of a wide range of planktonic taxa (Alveolata, Cryptophyta, Haptophyceae, Fungi, Metazoa, Hydrozoa, Rhizaria, Straminipila, Chlorophyta). Analyses based on predicted operational taxonomical units as well as taxonomical compositions revealed no differences between communities in high CO2 mesocosms (~ 760 μatm) and those exposed to present-day CO2 conditions. Observed shifts in the planktonic community composition were mainly related to seasonal changes in temperature and nutrients. Furthermore, based on our investigations, the elevated CO2 did not affect the intraspecific diversity of the most common mesozooplankter, the calanoid copepod Pseudocalanus acuspes. Nevertheless, accompanying studies found temporary effects attributed to a raise in CO2. Differences in taxa composition between the CO2 treatments could, however, only be observed in a specific period of the experiment. Based on our genetic investigations, no compositional long-term shifts of the plankton communities exposed to elevated CO2 conditions were observed. Thus, we conclude that the compositions of planktonic communities, especially those in coastal areas, remain rather unaffected by increased CO2.

Effect of estradiol on planktonic growth, coaggregation, and biofilm formation of the Prevotella intermedia group bacteria.

Science.gov (United States)

Fteita, Dareen; Könönen, Eija; Söderling, Eva; Gürsoy, Ulvi Kahraman

2014-06-01

Alterations in the quantity and quality of biofilms at gingival margin are considered to play a role in the initiation and development of pregnancy-related gingivitis. Prevotella intermedia sensu lato is able to consume estradiol, the major sex hormone secreted during pregnancy, in the absence of vitamin K. The aim of the study was to examine the effect of estradiol on the planktonic growth, coaggregation, polysaccharide production, and biofilm formation of the P. intermedia group bacteria, namely P. intermedia, Prevotella nigrescens, and Prevotella pallens. In all experiments, the type strain (ATCC) and a clinical strain (AHN) of P. intermedia, P. nigrescens, and P. pallens were incubated with the concentrations of 0, 30, 90, and 120 nmol/L of estradiol. Planktonic growth was assessed by means of the colony forming unit method, while coaggregation and biofilm formation were assessed by spectrophotometric methods. In the determination of protein and polysaccharide levels, the Bradford and phenol-sulfuric acid methods were used, respectively. P. pallens AHN 9283 and P. nigrescens ATCC 33563 increased their numbers at planktonic stage with increasing estradiol concentrations. In 48-h biofilm tests, elevated protein levels were found for both strains of P. intermedia, and the strains P. nigrescens ATCC 33563 and P. pallens AHN 9283 in the presence of estradiol. The P. intermedia strains also increased the levels of polysaccharide formation in the biofilm. Coaggregation of the P. intermedia group organisms with Fusobacterium nucleatum was enhanced only in P. intermedia AHN 8290. In conclusion, our in vitro experiments indicate that estradiol regulates planktonic growth, coaggregation, polysaccharide production, and biofilm formation characteristics of P. intermedia, P. nigrescens, and P. pallens differently. These results may, at least partly, explain the differences seen in their contribution to the pathogenesis of pregnancy-related gingivitis

Influence of ocean acidification on plankton community structure during a winter-to-summer succession: An imaging approach indicates that copepods can benefit from elevated CO2 via indirect food web effects

Science.gov (United States)

Taucher, Jan; Haunost, Mathias; Boxhammer, Tim; Bach, Lennart T.; Algueró-Muñiz, María; Riebesell, Ulf

2017-01-01

Plankton communities play a key role in the marine food web and are expected to be highly sensitive to ongoing environmental change. Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. These changes–summarized by the term ocean acidification (OA)–can significantly affect the physiology of planktonic organisms. However, studies on the response of entire plankton communities to OA, which also include indirect effects via food-web interactions, are still relatively rare. Thus, it is presently unclear how OA could affect the functioning of entire ecosystems and biogeochemical element cycles. In this study, we report from a long-term in situ mesocosm experiment, where we investigated the response of natural plankton communities in temperate waters (Gullmarfjord, Sweden) to elevated CO2 concentrations and OA as expected for the end of the century (~760 μatm pCO2). Based on a plankton-imaging approach, we examined size structure, community composition and food web characteristics of the whole plankton assemblage, ranging from picoplankton to mesozooplankton, during an entire winter-to-summer succession. The plankton imaging system revealed pronounced temporal changes in the size structure of the copepod community over the course of the plankton bloom. The observed shift towards smaller individuals resulted in an overall decrease of copepod biomass by 25%, despite increasing numerical abundances. Furthermore, we observed distinct effects of elevated CO2 on biomass and size structure of the entire plankton community. Notably, the biomass of copepods, dominated by Pseudocalanus acuspes, displayed a tendency towards elevated biomass by up to 30–40% under simulated ocean acidification. This effect was significant for certain copepod size classes and was most likely driven by CO2-stimulated responses of primary producers and a complex interplay of trophic interactions that allowed this

Atmospheric Deposition Effects on Plankton Communities in the Eastern Mediterranean: A Mesocosm Experimental Approach

Directory of Open Access Journals (Sweden)

Tatiana M. Tsagaraki

2017-07-01

Full Text Available The effects of atmospheric deposition on plankton community structure were examined during a mesocosm experiment using water from the Cretan Sea (Eastern Mediterranean, an area with a high frequency of atmospheric aerosol deposition events. The experiment was carried out under spring-summer conditions (May 2012. The main objective was to study the changes induced from a single deposition event, on the autotrophic and heterotrophic surface microbial populations, from viruses to zooplankton. To this end, the effects of Saharan dust addition were compared to the effects of mixed aerosol deposition on the plankton community over 9 days. The effects of the dust addition seemed to propagate throughout the food-web, with changes observed in nearly all of the measured parameters up to copepods. The dust input stimulated increased productivity, both bacterial and primary. Picoplankton, both autotrophic and heterotrophic capitalized on the changes in nutrient availability and microzooplankton abundance also increased due to increased availability of prey. Five days after the simulated deposition, copepods also responded, with an increase in egg production. The results suggest that nutrients were transported up the food web through autotrophs, which were favored by the Nitrogen supplied through both treatments. Although, the effects of individual events are generally short lived, increased deposition frequency and magnitude of events is expected in the area, due to predicted reduction in rainfall and increase in temperature, which can lead to more persistent changes in plankton community structure. Here we demonstrate how a single dust deposition event leads to enhancement of phytoplankton and microzooplankton and can eventually, through copepods, transport more nutrients up the food web in the Eastern Mediterranean Sea.

Shifts between gelatinous and crustacean plankton in a coastal upwelling region

OpenAIRE

Bode, Antonio; Álvarez-Ossorio, Maria Teresa; Miranda, Ana; Ruiz-Villarreal, Manuel

2013-01-01

proyectos RADIALES (IEO) y EURO-BASIN (Ref. 264933, 7FP) Variability in the dominance of copepods vs. gelatinous plankton was analysed using monthly time-series covering the last 55 years and related to changes in climatic, oceanographic, and fishery conditions in the upwelling region of Galicia (NW Spain). Seasonality was generally the main component of variability in all groups, both along the coast and in the nearby ocean, but no common long-term trend was found. Coastal copepo...

Incorporation of inorganic mercury (Hg{sup 2+}) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: The role of different plankton size fractions and species assemblages

Energy Technology Data Exchange (ETDEWEB)

Soto Cárdenas, Carolina, E-mail: sotocardenascaro@gmail.com [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina); Diéguez, Maria C. [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina); Ribeiro Guevara, Sergio [Laboratorio de Análisis por Activación Neutrónica, CAB, CNEA, Av. Bustillo Km 9.5, 8400, San Carlos de Bariloche, Río Negro (Argentina); Marvin-DiPasquale, Mark [United States Geological Survey, 345 Middlefield Rd./MS 480, Menlo Park, CA 94025 (United States); Queimaliños, Claudia P. [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina)

2014-10-01

In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg{sup 2+}) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg{sup 2+} by four plankton fractions (picoplankton: 0.2–2.7 μm; pico + nanoplankton: 0.2–20 μm; microplankton: 20–50 μm; and mesoplankton: 50–200 μm) obtained from four Andean Patagonian lakes, using the radioisotope {sup 197}Hg{sup 2+}. Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg{sup 2+} in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico + nanoplankton play a central role leading the incorporation of Hg{sup 2+} in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg{sup 2+} by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria–nanoflagellates–crustaceans; bacteria–ciliates–crustaceans; endosymbiotic algae–ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg{sup 2+} observed in all the plankton fractions. - Highlights: • Hg{sup 2+} incorporation in lake plankton fractions was studied using the isotope {sup 197}Hg{sup 2+}. • Hg{sup 2

Bioavailability of autochthonous dissolved organic nitrogen in marine plankton communities

DEFF Research Database (Denmark)

Knudsen, Helle; Markager, Svend Stiig; Søndergaard, Morten

The purpose of this study was to investigate the bioavailability of dissolved organic nitrogen (DON) produced during a phytoplankton bloom. The experiments were conducted with natural plankton communities as batch growth experiments over approximately 30 days with nitrogen limitation. Five to six...... times during the exponential and stationary phases of each experimental bloom the bioavailability of DON was measured over 60 days together with DOC and oxygen consumption. The overall aim was to quantify remineralization of the added nitrate. The results showed that maximum 33 % of the added nitrate...

Development of north sea coastal plankton communities in separate plastic bags under identical conditions

NARCIS (Netherlands)

Kuiper, J.

1977-01-01

In two experiments lasting 4 to 6 weeks, communities of North Sea coastal plankton kept in separate plastic bags (of about 1400 l) and exposed to the same environmental conditions showed very similar patterns of growth and decline. This result means that the method is suitable for the evaluation of

LC-MS-MS aboard ship: tandem mass spectrometry in the search for phycotoxins and novel toxigenic plankton from the North Sea.

Science.gov (United States)

Krock, Bernd; Tillmann, Urban; John, Uwe; Cembella, Allan

2008-11-01

Phycotoxins produced by various species of toxigenic microalgae occurring in the plankton are a global threat to the security of seafood resources and the health of humans and coastal marine ecosystems. This has necessitated the development and application of advanced methods in liquid chromatography coupled to mass spectrometry (LC-MS) for monitoring of these compounds, particularly in plankton and shellfish. Most such chemical analyses are conducted in land-based laboratories on stored samples, and thus much information on the near real-time biogeographical distribution and dynamics of phycotoxins in the plankton is unavailable. To resolve this problem, we conducted ship-board analysis of a broad spectrum of phycotoxins collected directly from the water column on an oceanographic cruise along the North Sea coast of Scotland, Norway, and Denmark. We equipped the ship with a triple-quadrupole linear ion-trap hybrid LC-MS-MS system for detection and quantitative analysis of toxins, such as domoic acid, gymnodimine, spirolides, dinophysistoxins, okadaic acid, pectenotoxins, yessotoxins, and azaspiracids (AZAs). We focused particular attention on the detection of AZAs, a group of potent nitrogenous polyether toxins, because the culprit species associated with the occurrence of these toxins in shellfish has been controversial. Marine toxins were analyzed directly from size-fractionated plankton net tows (20 microm mesh size) and Niskin bottle samples from discrete depths, after rapid methanolic extraction but without any further clean-up. Almost all expected phycotoxins were detected in North Sea plankton samples, with domoic acid and 20-methylspirolide G being most abundant. Although AZA was the least abundant of these toxins, the high sensitivity of the LC-MS-MS enabled detailed quantification, indicating that the highest amounts of AZA-1 were present in the southern Skagerrak in the 3-20 microm size-fraction. The direct on-board toxin measurements enabled isolation

The trophic role and impact of plankton ciliates in the microbial web structure of a tropical polymictic lake dominated by filamentous cyanobacteria

OpenAIRE

Alfonso Esquivel; Aude Barani; Miroslav Macek; Ruth Ruth Soto-Castor; Celia Bulit

2016-01-01

The recent interest in the plankton structures and dynamics in tropical and subtropical lakes has revealed important trends that set these lakes apart from temperate lakes, and one of the main differences is the enhanced importance of the microbial food web with respect to net plankton. Ciliates are a key component of subtropical and tropical microbial webs because of their role as dominant picoplankton grazers and their ability to channel picoplankton production to the uppermost trophic leve...

Specialized activities and expression differences for Clostridium thermocellum biofilm and planktonic cells.

Science.gov (United States)

Dumitrache, Alexandru; Klingeman, Dawn M; Natzke, Jace; Rodriguez, Miguel; Giannone, Richard J; Hettich, Robert L; Davison, Brian H; Brown, Steven D

2017-02-27

Clostridium (Ruminiclostridium) thermocellum is a model organism for its ability to deconstruct plant biomass and convert the cellulose into ethanol. The bacterium forms biofilms adherent to lignocellulosic feedstocks in a continuous cell-monolayer in order to efficiently break down and uptake cellulose hydrolysates. We developed a novel bioreactor design to generate separate sessile and planktonic cell populations for omics studies. Sessile cells had significantly greater expression of genes involved in catabolism of carbohydrates by glycolysis and pyruvate fermentation, ATP generation by proton gradient, the anabolism of proteins and lipids and cellular functions critical for cell division consistent with substrate replete conditions. Planktonic cells had notably higher gene expression for flagellar motility and chemotaxis, cellulosomal cellulases and anchoring scaffoldins, and a range of stress induced homeostasis mechanisms such as oxidative stress protection by antioxidants and flavoprotein co-factors, methionine repair, Fe-S cluster assembly and repair in redox proteins, cell growth control through tRNA thiolation, recovery of damaged DNA by nucleotide excision repair and removal of terminal proteins by proteases. This study demonstrates that microbial attachment to cellulose substrate produces widespread gene expression changes for critical functions of this organism and provides physiological insights for two cells populations relevant for engineering of industrially-ready phenotypes.

Mass Wasting during the Cretaceous/Tertiary Transition in the North Atlantic: Relationship to the Chicxulub Impact?

Science.gov (United States)

Mateo, Paula; Keller, Gerta; Adatte, Thierry; Spangenberg, Jorge

2015-04-01

Deep-sea sections in the North Atlantic are claimed to contain the most complete sedimentary records and ultimate proof that the Chicxulub impact is Cretaceous-Tertiary boundary (KTB) in age and caused the mass extinction. A multi-disciplinary study of North Atlantic DSDP Sites 384, 386 and 398, based on high-resolution planktonic foraminiferal biostratigraphy, carbon and oxygen stable isotopes, clay and whole-rock mineralogy and granulometry, reveals the age, stratigraphic completeness and nature of sedimentary disturbances. Results show a major KTB hiatus at Site 384 with zones CF1, P0 and P1a missing, spanning at least ~540 ky, similar to other North Atlantic and Caribbean localities associated with tectonic activity and Gulf Stream erosion. At Sites 386 and 398, discrete intervals of disturbed sediments with mm-to-cm-thick spherule layers have previously been interpreted as KTB age impact-generated earthquakes destabilizing continental margins prior to settling of impact spherules. However, improved age control based on planktonic foraminifera indicates deposition in the early Danian zone P1a(2) (upper Parvularugoglobigerina eugubina zone) more than 100 ky after the KTB. At Site 386, two intervals of white chalk contain very small (winnowing via distal turbidites. At Site 398, convoluted red to tan sediments with early Danian and reworked Cretaceous species represent slumping of shallow water sediments as suggested by dominance of mica and low smectite compared to in situ deposition. We conclude that mass wasting was likely the result of earthquakes associated with increased tectonic activity in the Caribbean and the Iberian Peninsula during the early Danian well after the Chicxulub impact.

Impact of restriction of the Atlantic-Mediterranean gateway on the Mediterranean Outflow Water and eastern Atlantic circulation during the Messinian

Science.gov (United States)

PéRez-Asensio, J. N.; Aguirre, J.; Schmiedl, G.; Civis, J.

2012-09-01

Messinian foraminiferal stable oxygen and carbon isotopes of the Montemayor-1 core (Guadalquivir Basin, SW Spain) have been investigated. This record is exceptional to study the Mediterranean Outflow Water (MOW) impact on the Atlantic meridional overturning circulation (AMOC) and global climate during the Messinian because the core is near the Guadalhorce Corridor, the last Betic gateway to be closed during the early Messinian. Our results allow dating accurately its closure at 6.18 Ma. Constant benthicδ18O values, high difference between benthic and planktonic δ18O, and low sedimentation rates before 6.18 Ma indicate the presence of a two-layer water column, with bottom winnowing due to an enhanced Mediterranean outflow current. The enhanced contribution of dense MOW to the North Atlantic Ocean likely fostered the formation of North Atlantic Deep Water (NADW). After 6.18 Ma, benthicδ18O values parallel that of the global glacioeustatic curve, the difference between benthic and planktonic δ18O is low, and sedimentation rates considerably increased. This indicates a good vertical mixing of the water column, interruption of the MOW, and a dominant glacioeustatic control on the isotopic signatures. According to the role of MOW in the modern Atlantic thermohaline circulation, the reduction of the MOW after the closure of the Guadalhorce Corridor might have resulted in a decreased NADW formation rate between 6.0 and 5.5 Ma weakening the AMOC and promoting northern hemisphere cooling. After the Gibraltar Strait opening, the restoration of the MOW and related salt export from the Mediterranean could have promoted an enhanced NADW formation.

The planktonic communities of the Jamaican south-east coast; a comparison of harbor, shelf and oceanic areas

Directory of Open Access Journals (Sweden)

Hugh Small

2014-09-01

Full Text Available Few studies have compared water quality and plankton along the eutrophication gradient from Kingston Harbour to oceanic waters around Jamaica. To compare the planktonic community along the expected nutrient gradient, we sampled every two weeks at four stations, from eutrophic Kingston Harbour to oceanic California Bank. Phytoplankton was assessed from whole water Niskin bottle casts and zooplankton by vertical hauls with plankton nets of three different mesh sizes: 64µm, 200µm, and 600µm. Total phytoplankton biomass declined sharply away from the harbour (1.0 μg L-1 at the Harbour Shoal Beacon to 0.2 μg L-1 at California Bank. Characteristic estuarine phytoplankton genera -such as Ceratium, Gonyaulax, Gyrodinium and Rhizosolenia- dominated harbour samples while genera characteristic of offshore locations -such as Asterionelliopsis, Navicula, Nitzschia, Rhizosolenia and Thalassionema- dominated California Bank. Highest phytoplankton densities (mean values of 34 174 cells L-1 were found at the harbor mouth. Mean zooplankton abundances ranged from maximum (5 858.5m-3 at Beacon to minimum (2 124.2 m-3 at California; 171 species of zooplankton were identified and copepods dominated with 76 species. Overall, 75 species of zooplankton were identified from Beacon, 107 from Port Royal Cays- South East Cay, 110 from the exposed shelf edge- Windward Edge, and 95 from the oceanic California Bank. Larval forms dominated; copepod nauplii, fish eggs and echinoderm larvae occurred at all sites. Lucifer faxoni and Penilia avirostris were indicative of harbor waters and Microsetella sp. and Farranula carinata of offshore waters. Some zooplankton taxa, like L. faxoni, Paracalanus parvus and copepod nauplii, despite showing gradual decline with distance from Beacon to the Edge, increased in abundance at the furthest station, California. California Bank clearly experiences enrichment which at times can be as high as near-shore areas, but the planktonic

A long-term study on crustacean plankton of a shallow tropical lake: the role of invertebrate predation

Directory of Open Access Journals (Sweden)

Marlene S. Arcifa

2015-06-01

Full Text Available The primary factor that governs the size and species composition of zooplankton is still a controversial issue and temperature is considered the main factor responsible for latitudinal differences. In waters with a narrow temperature range, such as in the tropics, predation may be a more important factor. Nearly three decades of intermittent studies of the crustacean plankton in a shallow tropical lake revealed that the main event that led to their restructuring was the appearance of a second predator, the water mite Krendowskia sp. The new predator and larvae of the dipteran Chaoborus brasiliensis Theobald exerted a combined, although asymmetrical effect on microcrustaceans. The period when the mite was detected was followed by the restructuring of the crustacean plankton community. Predation by these two invertebrates emerged as the factor responsible for community changes, involving an increased contribution of copepods and decreases in the relative abundance of smaller cladoceran species. In the short term, the mite caused a decrease in species richness and the annual mean instantaneous composition of cladocerans, a predominance of large-sized species (Daphnia ambigua Scourfield and Daphnia gessneri Herbst and the virtual disappearance of small species (e.g., Bosmina tubicen Brehm. The long-term impact resulted in increased species richness and the dominance of large and medium-sized cladocerans, such as D. gessneri and Ceriodaphnia richardi Sars. The larger body size of three cladocerans, the two Daphnia species and B. tubicen, in the long term, may be a response to the dominant predator, Chaoborus. The seasonal variation in the predator abundance, mainly Chaoborus larvae, allowed the prey to recover during the cool season. The copepods Tropocyclops prasinus meridionalis (Fischer and Thermocyclops decipiens Kiefer were less affected by predation than the cladocerans; their contribution to the crustacean plankton increased 12-28% after the

Effect of ocean acidification on the fatty acid composition of a natural plankton community

Directory of Open Access Journals (Sweden)

E. Leu

2013-02-01

Full Text Available The effect of ocean acidification on the fatty acid composition of a natural plankton community in the Arctic was studied in a large-scale mesocosm experiment, carried out in Kongsfjorden (Svalbard, Norway at 79° N. Nine mesocosms of ~50 m³ each were exposed to 8 different pCO₂ levels (from natural background conditions to ~1420 μatm, yielding pH values (on the total scale from ~8.3 to 7.5. Inorganic nutrients were added on day 13. The phytoplankton development during this 30-day experiment passed three distinct phases: (1 prior to the addition of inorganic nutrients, (2 first bloom after nutrient addition, and (3 second bloom after nutrient addition. The fatty acid composition of the natural plankton community was analysed and showed, in general, high percentages of polyunsaturated fatty acids (PUFAs: 44–60% of total fatty acids. Positive correlations with pCO₂ were found for most PUFAs during phases 2 and/or 3, with the exception of 20:5n3 (eicosapentaenoic acid, EPA, an important diatom marker. These correlations are probably linked to changes in taxonomic composition in response to pCO₂. While diatoms (together with prasinophytes and haptophytes increased during phase 3 mainly in the low and intermediate pCO₂ treatments, dinoflagellates were favoured by high CO₂ concentrations during the same time period. This is reflected in the development of group-specific fatty acid trophic markers. No indications were found for a generally detrimental effect of ocean acidification on the planktonic food quality in terms of essential fatty acids.

Habitat suitability and ecological niches of different plankton functional types in the global ocean

Science.gov (United States)

Vogt, Meike; Brun, Philipp; Payne, Mark R.; O'Brien, Colleen J.; Bednaršek, Nina; Buitenhuis, Erik T.; Doney, Scott C.; Leblanc, Karine; Le Quéré, Corinne; Luo, Yawei; Moriarty, Róisín; O'Brien, Todd D.; Schiebel, Ralf; Swan, Chantal

2013-04-01

Marine plankton play a central role in the biogeochemical cycling of important elements such as carbon, nitrogen, and sulphur. While our knowledge about marine ecosystem structure and functioning is still scarce and episodic, several recent observational studies confirm that marine ecosystems have been changing due to recent climate change, overfishing, and coastal eutrophication. In order to better understand marine ecosystem dynamics, the MAREDAT initiative has recently collected abundance and biomass data for 5 autotrophic (diatoms, Phaeocystis, coccolithophores, nitrogen fixers, picophytoplankton), and 6 heterotrophic plankton functional types (PFTs; bacteria, micro-, meso- and macrozooplankton, foraminifera and pteropods). Species distribution models (SDMs) are statistical tools that can be used to derive information about species habitats in space and time. They have been used extensively for a wide range of ecological applications in terrestrial ecosystems, but here we present the first global application in the marine realm, which was made possible by the MAREDAT data synthesis effort. We use a maximum entropy SDM to simulate global habitat suitability, habitat extent and ecological niches for different PFTs in the modern ocean. Present habitat suitability is derived from presence-only MAREDAT data and the observed annual and monthly mean levels of physiologically relevant variables such as SST, nutrient concentration or photosynthetic active radiation received in the mixed layer. This information can then be used to derive ecological niches for different species or taxa within each PFT, and to compare the ecological niches of different PFTs. While these results still need verification because data was not available for all ocean regions for all PFTs, they can give a first indication what present and future plankton habitats may look like, and what consequences we may have to expect for future marine ecosystem functioning and service provision in a warmer

EOCENE LARGER FORAMINIFERAL BIOSTRATIGRAPHY IN THE SOUTHERNMOST DAUPHINOIS DOMAIN (MARITIME ALPS, FRANCE-ITALY BORDER

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DARIO VARRONE

2007-07-01

Full Text Available The Trucco Formation and the Nummulitic Limestone (Dauphinois Domain, Maritime Alps are characterized by abundant larger foraminifera, specifically nummulitids, orthophragminids and encrusting foraminifera. In the Maritime Alps, previous studies suggest a late Lutetian age for the Trucco Formation and a late Lutetian-Priabonian age for the Nummulitic Limestone.Biostratigraphic analysis of the nummulitids, in 11 stratigraphic sections, allowed us to distinguish 3 biozones:MALF1 Zone: defined by the presence of Nummulites brongniarti d’Archiac & Haime, N. puschi d’Archiac, N. perforatus de Montfort, N. striatus (Bruguière, N. cf. dufrenoyi d’Archiac & Haime, N. variolarius/incrassatus and Operculina schwageri Silvestri.MALF2 Zone: defined by the presence of Nummulites perforatus de Montfort, N. striatus (Bruguière, N. cf. dufrenoyi d’Archiac & Haime, N. variolarius/incrassatus and Operculina schwageri Silvestri.MALF 3 Zone: defined by the presence of gr. Nummulites variolarius/incrassatus, N. striatus (Bruguière and Operculina schwageri Silvestri.According to current larger foraminiferal biozonal schemes, the age of these local biozones corresponds to the Bartonian p.p.Moreover, the comparison with biostratigraphic schemes established for the Dauphinois Domain and for the Tethyan area evidences that several typical nummulitid species of the late Bartonian are lacking in the southern Dauphinois Domain, probably due to a paleogeographic control. 

PlanktonSet 1.0: Plankton imagery data collected from F.G. Walton Smith in Straits of Florida from 2014-06-03 to 2014-06-06 and used in the 2015 National Data Science Bowl (NCEI Accession 0127422)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Data presented here are subset of a larger plankton imagery data set collected in the subtropical Straits of Florida from 2014-05-28 to 2014-06-14. Imagery data were...

Moderate effect of damming the Romaine River (Quebec, Canada) on coastal plankton dynamics

Science.gov (United States)

Senneville, Simon; Schloss, Irene R.; St-Onge Drouin, Simon; Bélanger, Simon; Winkler, Gesche; Dumont, Dany; Johnston, Patricia; St-Onge, Isabelle

2018-04-01

Rivers' damming disrupts the seasonal cycle of freshwater and nutrient inputs into the marine system, which can lead to changes in coastal plankton dynamics. Here we use a 3-D 5-km resolution coupled biophysical model and downscale it to a 400-m resolution to simulate the effect of damming the Romaine River in Québec, Canada, which discharges on average 327 m3 s-1 of freshwater into the northern Gulf of St. Lawrence. Model results are compared with environmental data obtained from 2 buoys and in situ sampling near the Romaine River mouth during the 2013 spring-summer period. Noteworthy improvements are made to the light attenuation parametrization and the trophic links of the biogeochemical model. The modelled variables reproduced most of the observed levels of variability. Comparisons between natural and regulated discharge simulation show differences in primary production and in the dominance of plankton groups in the Romaine River plume. The maximum increase in primary production when averaged over the inner part of Mingan Archipelago is 41%, but 7.1% when the primary production anomaly is averaged from March to September.

Incorporation of inorganic mercury (Hg²⁺) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: the role of different plankton size fractions and species assemblages.

Science.gov (United States)

Soto Cárdenas, Carolina; Diéguez, Maria C; Ribeiro Guevara, Sergio; Marvin-DiPasquale, Mark; Queimaliños, Claudia P

2014-10-01

In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg(2+)) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg(2+) by four plankton fractions (picoplankton: 0.2-2.7 μm; pico+nanoplankton: 0.2-20 μm; microplankton: 20-50 μm; and mesoplankton: 50-200 μm) obtained from four Andean Patagonian lakes, using the radioisotope (197)Hg(2+). Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg(2+) in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico+nanoplankton play a central role leading the incorporation of Hg(2+) in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg(2+) by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria-nanoflagellates-crustaceans; bacteria-ciliates-crustaceans; endosymbiotic algae-ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg(2+) observed in all the plankton fractions. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of ocean warming and acidification on a plankton community in the NW Mediterranean Sea

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Maugendre, L.; Gattuso, J.-P.; Louis, J.; de Kluijver, A.; Marro, S.; Soetaert, K.; Gazeau, F.

2015-01-01

The effect of ocean warming and acidification was investigated on a natural plankton assemblage from an oligotrophic area, the bay of Villefranche (NW Mediterranean Sea). The assemblage was sampled in March 2012 and exposed to the following four treatments for 12 days: control (~360 µatm, 14°C),

Scaling of fecundity, growth and development in marine planktonic copepods

DEFF Research Database (Denmark)

Kiørboe, Thomas; Sabatini, M.

1995-01-01

We compiled information from the literature on female and egg sizes and maximum egg production, growth and developmental rates in marine planktonic copepods. While specific growth and developmental rates are invariant with body mass, weight- specific fecundity scales with female body mass(-0...... to 50% and have weight-specific fecundities that are 2.5 times and egg production rates that are 7.5 times those of the former, Nauplii develop faster (by a factor of 2) but grow slower (by 20 to 40%) than copepodites in both spawning types. The main demographic implications of these findings are (1...

Diatom Stratigraphy of FA-1 Core, Qarun Lake, Records of Holocene Environmental and Climatic Change in Faiyum Oasis, Egypt

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Zalat Abdelfattah A.

2017-06-01

Full Text Available This study evaluates changes in the environmental and climatic conditions in the Faiyum Oasis during the Holocene based on diatom analyses of the sediment FA-1 core from the southern seashore of the Qarun Lake. The studied FA-1 core was 26 m long and covered the time span ca. 9.000 cal. yrs BP. Diatom taxa were abundant and moderately to well-preserved throughout the core sediments. Planktonic taxa were most abundant than the benthic and epiphytic forms, which were very rare and sparsely distributed. The most dominant planktonic genera were Aulacoseira and Stephanodiscus followed by frequently distribution of Cyclostephanos and Cyclotella species. The stratigraphic distribution patterns of the recorded diatoms through the Holocene sediments explained five ecological diatom groups. These groups represent distinctive environmental conditions, which were mainly related to climatic changes through the early and middle Holocene, in addition to anthropogenic activity during the late Holocene. Comparison of diatom assemblages in the studied sediment core suggests that considerable changes occurred in water level as well as salinity. There were several high stands of the freshwater lake level during humid, warmer-wet climatic phases marked by dominance of planktonic, oligohalobous and alkaliphilous diatoms alternated with lowering of the lake level and slight increases in salinity and alkalinity during warm arid conditions evident by prevalence of brackish water diatoms.

Differential Protein Expression in Streptococcus uberis under Planktonic and Biofilm Growth Conditions ▿ †

Science.gov (United States)

Crowley, R. C.; Leigh, J. A.; Ward, P. N.; Lappin-Scott, H. M.; Bowler, L. D.

2011-01-01

The bovine pathogen Streptococcus uberis was assessed for biofilm growth. The transition from planktonic to biofilm growth in strain 0140J correlated with an upregulation of several gene products that have been shown to be important for pathogenesis, including a glutamine ABC transporter (SUB1152) and a lactoferrin binding protein (gene lbp; protein SUB0145). PMID:21075893

Limnology and plankton diversity of salt lakes from Transylvanian Basin (Romania: A review

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Mircea Alexe

2017-09-01

Full Text Available In the present work, we review the current knowledge on genesis, limnology and biodiversity of salt lakes distributed around the inner contour of Eastern Carpathian arc (Transylvanian Basin, Central Romania. Transylvanian salt lakes formed on ancient halite (NaCl deposits following natural processes or quarrying activities.  Most of these lakes are located in eastern (Sovata area, southern (Ocna Sibiului, and western (Turda-Cojocna parts of the Transylvanian Basin, have small surfaces (0.1-4 ha, variable depths (2-100 m, are hypersaline (>10%, w/v, total salts, mainly NaCl and permanently stratified. As consequence of steady salinity/density gradient, heat entrapment below surface layer (i.e., heliothermy develops in several Transylvanian lakes. The physical and chemical water stratification is mirrored in the partition of plankton diversity. Lakes with less saline (2-10% salinity water layers appear to harbor halotolerant representatives of phyto- (e.g., marine native Picochlorum spp. and Synechococcus spp., zoo- (e.g., Moina salina, and bacterioplankton (e.g., Actinobacteria, Verrucomicobia, whereas halophilic plankton communities (e.g., green algae Dunaliella sp., brine shrimp Artemia sp., and members of Halobacteria class dominate in the oxic surface of hypersaline (>10% salinity lakes. Molecular approaches (e.g., PCR-DGGE, 16S rRNA gene-based clone libraries, and DNA metabarcoding showed that the O2-depleted bottom brines of deep meromictic Transylvanian lakes are inhabited by known extremely halophilic anaerobes (e.g. sulfate-reducing Delta-Proteobacteria, fermenting Clostridia, methanogenic and polymer-degrading archaea in addition to representatives of uncultured/unclassified prokaryotic lineages. Overall, the plankton communities thriving in saline Transylvanian lakes seem to drive full biogeochemical cycling of main elements. However, the trophic interactions (i.e., food web structure and energy flow as well as impact of human

Acclimation, adaptation, traits and trade-offs in plankton functional type models – seeking clarity in terminology

DEFF Research Database (Denmark)

Flynn, Kevin J.; St. John, Michael; Raven, John A.

2015-01-01

We propose definitions in terminology to enhance ongoing collaborations between biologists and modellers on plankton ecology. Organism “functional type” should refer to commonality in ecology not biogeochemistry; the latter is largely an emergent property of the former, while alignment with ecology...

Combined treatments of enterocin AS-48 with biocides to improve the inactivation of methicillin-sensitive and methicillin-resistant Staphylococcus aureus planktonic and sessile cells.

Science.gov (United States)

Caballero Gómez, Natacha; Abriouel, Hikmate; Grande, M José; Pérez Pulido, Rubén; Gálvez, Antonio

2013-05-15

Control of staphylococci during cleaning and disinfection is important to the food industry. Broad-spectrum bacteriocins with proved anti-staphylococcal activity, such as enterocin AS-48, could open new possibilities for disinfection in combination with biocides. In the present study, enterocin AS-48 was tested singly or in combination with biocides against a cocktail of six Staphylococcus aureus strains (including three methicillin-resistant strains) in planktonic state as well as in biofilms formed on polystyrene microtiter plates. Cells were challenged with enterocin, biocides or enterocin/biocide combinations. Inactivation of planktonic cells increased significantly (penterocin AS-48 (25mg/l) was tested in combination with benzalkonium chloride (BC), cetrimide (CT) and hexadecylpyridinium chloride (HDP), and non-significantly in combination with didecyldimethylammonium bromide (AB), triclosan (TC), hexachlorophene (CF), polyhexamethylen guanidinium chloride (PHMG), chlorhexidine (CH) or P3-oxonia (OX). In the sessile state (24h biofilms), staphylococci required higher biocide concentrations in most cases, except for OX. Inactivation of sessile staphylococci increased remarkably when biocides were applied in combination with enterocin AS-48, especially when the bacteriocin was added at 50mg/l. During storage, the concentrations of sessile as well as planktonic cells in the treated samples decreased remarkably for BC, TC and PHMG, but OX failed to inhibit proliferation of the treated biofilms as well as growth of planktonic cells. The observed inhibitory effects during storage were potentiated when the biocides were combined with 50 mg/l enterocin AS-48. Results from this study suggest that selected combinations of enterocin AS-48 and biocides offer potential use against planktonic and sessile, methicillin-sensitive and methicillin-resistant S. aureus. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of climate change on bioaccumulation and biomagnification of polycyclic aromatic hydrocarbons in the planktonic food web of a subtropical shallow eutrophic lake in China.

Science.gov (United States)

Tao, Yuqiang; Xue, Bin; Lei, Guoliang; Liu, Fei; Wang, Zhen

2017-04-01

To date effects of climate change on bioaccumulation and biomagnification of chemical pollutants in planktonic food webs have rarely been studied. Recruitments of plankton have shifted earlier due to global warming. Global warming and precipitation patterns are projected to shift seasonally. Whether and how the shifts in plankton phenology induced by climate change will impact bioaccumulation and biomagnification of chemical pollutants, and how they will respond to climate change are largely unknown. Here, we combine data analysis of the past seven decades, high temporal resolution monitoring and model development to test this hypothesis with nine polycyclic aromatic hydrocarbons (PAHs) in the planktonic food web of a subtropical shallow eutrophic lake in China. We find biphasic correlations between both bioconcentration factors and bioaccumulation factors of the PAHs and the mean temperature, which depend on the recruitment temperatures of cyanobacteria, and copepods and cladocerans. The positive correlations between bioconcentration factors, bioaccumulation factors and the mean temperature will be observed less than approximately 13-18 days by 2050-2060 due to the shifts in plankton phenology. The PAHs and their bioaccumulation and biomagnification will respond seasonally and differently to climate change. Bioaccumulation of most of the PAHs will decrease with global warming, with higher decreasing rates appearing in winter and spring. Biomagnification of most of the PAHs from phytoplankton to zooplankton will increase with global warming, with higher increasing rates appearing in winter and spring. Our study provides novel insights into bioaccumulation and biomagnification of chemical pollutants in eutrophic waters under climate change scenarios. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preliminary Transcriptome Analysis of Mature Biofilm and Planktonic Cells of Salmonella Enteritidis Exposure to Acid Stress

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Kun Jia

2017-09-01

Full Text Available Salmonella has emerged as a well-recognized food-borne pathogen, with many strains able to form biofilms and thus cause cross-contamination in food processing environments where acid-based disinfectants are widely encountered. In the present study, RNA sequencing was employed to establish complete transcriptome profiles of Salmonella Enteritidis in the forms of planktonic and biofilm-associated cells cultured in Tryptic Soytone Broth (TSB and acidic TSB (aTSB. The gene expression patterns of S. Enteritidis significantly differed between biofilm-associated and planktonic cells cultivated under the same conditions. The assembled transcriptome of S. Enteritidis in this study contained 5,442 assembled transcripts, including 3,877 differentially expressed genes (DEGs identified in biofilm and planktonic cells. These DEGs were enriched in terms such as regulation of biological process, metabolic process, macromolecular complex, binding and transferase activity, which may play crucial roles in the biofilm formation of S. Enteritidis cultivated in aTSB. Three significant pathways were observed to be enriched under acidic conditions: bacterial chemotaxis, porphyrin-chlorophyll metabolism and sulfur metabolism. In addition, 15 differentially expressed novel non-coding small RNAs (sRNAs were identified, and only one was found to be up-regulated in mature biofilms. This preliminary study of the S. Enteritidis transcriptome serves as a basis for future investigations examining the complex network systems that regulate Salmonella biofilm in acidic environments, which provide information on biofilm formation and acid stress interaction that may facilitate the development of novel disinfection procedures in the food processing industry.

Variable Responses to Carbon Utilization between Planktonic and Biofilm Cells of a Human Carrier Strain of Salmonella enterica Serovar Typhi.

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Kalaivani Kalai Chelvam

Full Text Available Salmonella enterica serovar Typhi (S. Typhi is a foodborne pathogen that causes typhoid fever and infects only humans. The ability of S. Typhi to survive outside the human host remains unclear, particularly in human carrier strains. In this study, we have investigated the catabolic activity of a human carrier S. Typhi strain in both planktonic and biofilm cells using the high-throughput Biolog Phenotype MicroArray, Minimum Biofilm Eradication Concentration (MBEC biofilm inoculator (96-well peg lid and whole genome sequence data. Additional strains of S. Typhi were tested to further validate the variation of catabolism in selected carbon substrates in the different bacterial growth phases. The analyzes of the carbon utilization data indicated that planktonic cells of the carrier strain, S. Typhi CR0044 could utilize a broader range of carbon substrates compared to biofilm cells. Pyruvic acid and succinic acid which are related to energy metabolism were actively catabolised in the planktonic stage compared to biofilm stage. On the other hand, glycerol, L-fucose, L-rhamnose (carbohydrates and D-threonine (amino acid were more actively catabolised by biofilm cells compared to planktonic cells. Notably, dextrin and pectin could induce strong biofilm formation in the human carrier strain of S. Typhi. However, pectin could not induce formation of biofilm in the other S. Typhi strains. Phenome data showed the utilization of certain carbon substrates which was supported by the presence of the catabolism-associated genes in S. Typhi CR0044. In conclusion, the findings showed the differential carbon utilization between planktonic and biofilm cells of a S. Typhi human carrier strain. The differences found in the carbon utilization profiles suggested that S. Typhi uses substrates mainly found in the human biliary mucus glycoprotein, gallbladder, liver and cortex of the kidney of the human host. The observed diversity in the carbon catabolism profiles among

Water masses in Kangerlussuaq, a large fjord in West Greenland: the processes of formation and the associated foraminiferal fauna

DEFF Research Database (Denmark)

Nielsen, Morten Holtegaard; Erbs-Hansen, Dorthe Reng; Knudsen, Karen Luise

2010-01-01

–temperature–density measurements were carried out in connection with sediment surface sampling along a transect through the 180 km long fjord. The exchange between the inner part of Kangerlussuaq (275 m deep) and the ocean is restricted by an almost 100 km long outer, shallow part. Our study shows that the water mass...... in this inner part is almost decoupled from the open ocean, and that in winter the inner part of the fjord is ice covered and convection occurs as a result of brine release. These processes are reflected in the foraminiferal assemblage, which consists of a sparse agglutinated fauna, indicative of carbonate...... dissolution. A monospecific, calcareous assemblage (Elphidium excavatum forma clavata) occurs in the innermost, shallow part, which is strongly influenced by sediment-loaded meltwater during the summer. The outer, shallow part of the fjord is dominated by strong tidal mixing, and in summer the density...

Comparative study on composition and abundance of major planktons and physico-chemical characteristics among two ponds and Lake Tana, Ethiopia

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Wondie Zelalem Amanu

2015-11-01

Full Text Available Objective: To evaluate the difference in physico-chemical characteristics, composition and abundance of plankton communities owing to the supplementary feed added in fish ponds as compared to Lake Tana. Methods: Physico-chemical and biological data of plankton were collected from 3 studied sites from November 2008 to October 2009. Data were compared using One-way ANOVA to see the difference among sites. Diversity indices such as Margalef's index, Shannon-Wiener index, and evenness index were employed to describe the distribution of plankton community among the studied sites. Results: The pH value was remarkably higher in ponds water. However, conductivity and total dissolved solids were the highest in lake water. Nitrate concentration was relatively high in ponds. Zooplankton species richness was higher in lake water than ponds. The lake also had the highest mean value of both Shannon-Wiener index and evenness index in phytoplankton. Conclusions: The results revealed that the supplementary feed added to each pond had influence on nutrient content which enhanced algal biomass and productivity of the ponds. However, the pond water has to be regularly refreshed to control eutrophication.

Lagrangian modelling of plankton motion: From deceptively simple random walks to Fokker-Planck and back again

DEFF Research Database (Denmark)

Visser, Andre

2008-01-01

The movement of plankton, either by turbulent mixing or their own inherent motility, can be simulated in a Lagrangian framework as a random walk. Validation of random walk simulations is essential. There is a continuum of mathematically valid stochastic integration schemes upon which random walk...

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

Science.gov (United States)

Weiner, Agnes K M; Weinkauf, Manuel F G; Kurasawa, Atsushi; Darling, Kate F; Kucera, Michal; Grimm, Guido W

2014-01-01

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.

The role of ocean currents in the temperature selection of plankton : Insights from an individual-based model

NARCIS (Netherlands)

Hellweger, Ferdi L.; Van Sebille, Erik; Calfee, Benjamin C.; Chandler, Jeremy W.; Zinser, Erik R.; Swan, Brandon K.; Fredrick, Neil D.

2016-01-01

Biogeography studies that correlate the observed distribution of organisms to environmental variables are typically based on local conditions. However, in cases with substantial translocation, like planktonic organisms carried by ocean currents, selection may happen upstream and local environmental

Time-Resolved Analysis of Cytosolic and Surface-Associated Proteins of Staphylococcus aureus HG001 under Planktonic and Biofilm Conditions.

Science.gov (United States)

Moche, Martin; Schlüter, Rabea; Bernhardt, Jörg; Plate, Kristina; Riedel, Katharina; Hecker, Michael; Becher, Dörte

2015-09-04

Staphylococcal biofilms are associated with persistent infections due to their capacity to protect bacteria against the host's immune system and antibiotics. Cell-surface-associated proteins are of great importance during biofilm formation. In the present study, an optimized biotinylation approach for quantitative GeLC-MS-based analysis of the staphylococcal cell-surface proteome was applied and the cytoplasmic protein fraction was analyzed to elucidate proteomic differences between colony biofilms and planktonic cells. The experimental setup enabled a time-resolved monitoring of the proteome under both culture conditions and the comparison of biofilm cells to planktonic cells at several time points. This allowed discrimination of differences attributed to delayed growth phases from responses provoked by biofilm conditions. Biofilm cells expressed CcpA-dependent catabolic proteins earlier than planktonic cells and strongly accumulated proteins that belong to the SigB stress regulon. The amount of the cell-surface protein and virulence gene regulator Rot decreased within biofilms and MgrA-dependent regulations appeared more pronounced. Biofilm cells simultaneously up-regulated activators (e.g., SarZ) as well as repressors (e.g., SarX) of RNAIII. A decreased amount of high-affinity iron uptake systems and an increased amount of the iron-storage protein FtnA possibly indicated a lower demand of iron in biofilms.

Analysis of self-overlap reveals trade-offs in plankton swimming trajectories

DEFF Research Database (Denmark)

Mariani, Patrizio; Visser, Andre W.; Mazzocchi, Maria Grazia

2014-01-01

Movement is a fundamental behaviour of organisms that not only brings about beneficial encounters with resources and mates, but also at the same time exposes the organism to dangerous encounters with predators. The movement patterns adopted by organisms should reflect a balance between...... these contrasting processes. This trade-off can be hypothesized as being evident in the behaviour of plankton, which inhabit a dilute three-dimensional environment with few refuges or orienting landmarks. We present an analysis of the swimming path geometries based on a volumetric Monte Carlo sampling approach...

Role of Fusobacterium nucleatum and Coaggregation in Anaerobe Survival in Planktonic and Biofilm Oral Microbial Communities during Aeration

Science.gov (United States)

Bradshaw, David J.; Marsh, Philip D.; Watson, G. Keith; Allison, Clive

1998-01-01

Coaggregation is a well-characterized phenomenon by which specific pairs of oral bacteria interact physically. The aim of this study was to examine the patterns of coaggregation between obligately anaerobic and oxygen-tolerant species that coexist in a model oral microbial community. Obligate anaerobes other than Fusobacterium nucleatum coaggregated only poorly with oxygen-tolerant species. In contrast, F. nucleatum was able to coaggregate not only with both oxygen-tolerant and other obligately anaerobic species but also with otherwise-noncoaggregating obligate anaerobe–oxygen-tolerant species pairs. The effects of the presence or absence of F. nucleatum on anaerobe survival in both the biofilm and planktonic phases of a complex community of oral bacteria grown in an aerated (gas phase, 200 ml of 5% CO2 in air · min−1) chemostat system were then investigated. In the presence of F. nucleatum, anaerobes persisted in high numbers (>107 · ml−1 in the planktonic phase and >107 · cm−2 in 4-day biofilms). In an equivalent culture in the absence of F. nucleatum, the numbers of black-pigmented anaerobes (Porphyromonas gingivalis and Prevotella nigrescens) were significantly reduced (P ≤ 0.001) in both the planktonic phase and in 4-day biofilms, while the numbers of facultatively anaerobic bacteria increased in these communities. Coaggregation-mediated interactions between F. nucleatum and other species facilitated the survival of obligate anaerobes in aerated environments. PMID:9746571