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Sample records for quaternary reef growth

  1. Climatic and tectonic controls on late Quaternary reef growth in New Caledonia

    International Nuclear Information System (INIS)

    Cabioch, G.; Recy, J.; Jouannic, CH.; Turpin, L.

    1996-01-01

    Sedimentological and stratigraphic analysis of about 40 sub-surface cores drilled through the reefs of New Caledonia provides valuable data on the processes of reef recolonization following the past post glacial sea-level rise, and on the vertical tectonic behaviour of the island over the past 125,000 years. Holocene reefs in New Caledonia are not older than 8.5 ky. The fringing reef which developed during the last interglacial high sea-level 125 ky ago, is today uplifted and lies along some 30 km of coast in the area of 10 m, while the present-day barrier reef is deeply submerged (around - 15 to - 20 m). Near Hienghene (east coast), a double system of two notches is markedly deformed by a bulge, but is much more localized (3 km long) than in the Yate area, with a maximum uplift of 13 m of the upper double notch system (interpreted as having formed during the last interglacial event). Relics of the 125 ky fringing reef are emergent at various locations in the Bourail region (west coast). However, their altitudes are lower than that generally admitted (+ 6 m) for their construction at 125 ky, thus most probably reflecting a slight subsidence of the area. Elsewhere, the 125 ky fringing reef underlies the Holocene reef: in the SW of the island, in particular, the Holocene - Pleistocene unconformity is observed at - 6 m. In areas of higher subsidence rates, such as the NW or NE of the island, the 125 ky fringing reef may be more deeply buried. In that case, the Holocene reef rests directly on a metamorphic or sedimentary substratum. Within the barrier reef build-up itself, the 125 ky reef flat is overlain by a Holocene sequence, whose thickness depends on local subsidence rates. The observation of notches, raised becah-rocks or coral reefs (dated ar around 5,500 yr) uplifted up to 1 to 1,5 m above MLWS reflects the existence of a hydro-isostatic rebound. Traces of this rebound disappear in areas of high subsidence rate, illustrating the action of local tectonics

  2. Geochronology and subsurface stratigraphy of Pukapuka and Rakahanga atolls, Cook Islands: Late Quaternary reef growth and sea level history

    Science.gov (United States)

    Gray, S.C.; Hein, J.R.; Hausmann, R.; Radtke, U.

    1992-01-01

    Eustatic sea-level cycles superposed on thermal subsidence of an atoll produce layers of high sea-level reefs separated by erosional unconformities. Coral samples from these reefs from cores drilled to 50 m beneath the lagoons of Pukapuka and Rakahanga atolls, northern Cook Islands give electron spin resonance (ESR) and U-series ages ranging from the Holocene to 600,000 yr B.P. Subgroups of these ages and the stratigraphic position of their bounding unconformities define at least 5 periods of reef growth and high sea-level (0-9000 yr B.P., 125,000-180,000 yr B.P., 180,000-230,000 yr B.P., 300,000-460,000 yr B.P., 460,000-650,000 yr B.P.). Only two ages fall within error of the last interglacial high sea-level stand (???125,000-135,000 yr B.P.). This paucity of ages may result from extensive erosion of the last intergracial reef. In addition, post-depositional isotope exchange may have altered the time ages of three coral samples to apparent ages that fall within glacial stage 6. For the record to be preserved, vertical accretion during rising sea-level must compensate for surface lowering from erosion during sea-level lowstands and subsidence of the atoll; erosion rates (6-63 cm/1000 yr) can therefore be calculated from reef accretion rates (100-400 cm/1000 yr), subsidence rates (2-6 cm/1000 yr), and the duration of island submergence (8-15% of the last 600,000 yr). The stratigraphy of coral ages indicates island subsidence rates of 4.5 ?? 2.8 cm/1000 yr for both islands. A model of reef growth and erosion based on the stratigraphy of the Cook Islands atolls suggests average subsidence and erosion rates of between 3-6 and 15-20 cm/1000 yr, respectively. ?? 1992.

  3. Quaternary development of resilient reefs on the subsiding kimberley continental margin, Northwest Australia

    Directory of Open Access Journals (Sweden)

    Lindsay B. Collins

    2010-01-01

    Full Text Available The Kimberley region in remote northwest Australia has poorly known reef systems of two types; coastal fringing reefs and atoll-like shelf-edge reefs. As a major geomorphic feature (from 12ºS to 18ºS situated along a subsiding continental margin, the shelf edge reefs are in a tropical realm with warm temperatures, relatively low salinity, clear low nutrient waters lacking sediment input, and Indo-West Pacific corals of moderate diversity. Seismic architecture of the Rowley Shoals reveals that differential pre-Holocene subsidence and relative elevation of the pre-Holocene substrate have controlled lagoon sediment infill and reef morphology, forming an evolutionary series reflecting differential accommodation in three otherwise similar reef systems. The Holocene core described for North Scott Reef confirms previous seismic interpretations, and provides a rare ocean-facing reef record. It demonstrates that the Indo-Pacific reef growth phase (RG111 developed during moderate rates of sea level rise of 10 mm/year from 11 to about 7-6.5 ka BP until sea level stabilization, filling the available 27 m of pre-Holocene accommodation. Despite the medium to high hydrodynamic energy imposed by the 4m tides, swell waves and cyclones the reef-building communities represent relatively low-wave energy settings due to their southeast facing and protection afforded by the proximity of the South Reef platform. This study demonstrates the resilience of reefs on the subsiding margin whilst linking Holocene reef morphology to the relative amount of pre-Holocene subsidence.Kimberly é uma região remota e pouco conhecida, localizada no noroeste da Austrália, ali são encontrados dois sistemas recifais: recifes costeiros de franja e os tipo-atois localizados na margem da plataforma continental. Esses recifes formam a feição geomórfica mais importante entre 12ºS a 18ºS estando localizados ao longo de uma margem continental em subsidência. Esses recifes encontram

  4. Mineralogy, geochemistry and microfacies of late Quaternary periplatform sediments: Carbonate export cycles and secondary processes - Sanganeb Atoll and Abington Reef, Sudan, Central Red Sea

    OpenAIRE

    Emmermann, Peter

    2000-01-01

    A set of sediment cores was obtained in the periplatform realm close to Sanganeb Atoll and Abington Reef, about 20 miles offshore the Sudanese coast in the central Red Sea. Microfacies, mineralogy and geochemistry of periplatform sediments were analysed to quantify glacial-interglacial variations in carbonate production and sediment export of the reefs in response to late Quaternary sealevel fluctuations. The present study showed that the periplatform sediments from the Sudanese shelf to grea...

  5. Millennial-scale ocean acidification and late Quaternary decline of cryptic bacterial crusts in tropical reefs.

    Science.gov (United States)

    Riding, R; Liang, L; Braga, J C

    2014-09-01

    Ocean acidification by atmospheric carbon dioxide has increased almost continuously since the last glacial maximum (LGM), 21,000 years ago. It is expected to impair tropical reef development, but effects on reefs at the present day and in the recent past have proved difficult to evaluate. We present evidence that acidification has already significantly reduced the formation of calcified bacterial crusts in tropical reefs. Unlike major reef builders such as coralline algae and corals that more closely control their calcification, bacterial calcification is very sensitive to ambient changes in carbonate chemistry. Bacterial crusts in reef cavities have declined in thickness over the past 14,000 years with largest reduction occurring 12,000-10,000 years ago. We interpret this as an early effect of deglacial ocean acidification on reef calcification and infer that similar crusts were likely to have been thicker when seawater carbonate saturation was increased during earlier glacial intervals, and thinner during interglacials. These changes in crust thickness could have substantially affected reef development over glacial cycles, as rigid crusts significantly strengthen framework and their reduction would have increased the susceptibility of reefs to biological and physical erosion. Bacterial crust decline reveals previously unrecognized millennial-scale acidification effects on tropical reefs. This directs attention to the role of crusts in reef formation and the ability of bioinduced calcification to reflect changes in seawater chemistry. It also provides a long-term context for assessing anticipated anthropogenic effects. © 2014 John Wiley & Sons Ltd.

  6. Temporal and taxonomic contrasts in coral growth at Davies Reef, central Great Barrier Reef, Australia

    Science.gov (United States)

    Anderson, Kristen D.; Cantin, Neal E.; Heron, Scott F.; Lough, Janice M.; Pratchett, Morgan S.

    2018-06-01

    Demographic processes, such as growth, can have an important influence on the population and community structure of reef-building corals. Importantly, ongoing changes in environmental conditions (e.g. ocean warming) are expected to affect coral growth, contributing to changes in the structure of coral populations and communities. This study quantified contemporary growth rates (linear extension and calcification) for the staghorn coral, Acropora muricata, at Davies Reef, central Great Barrier Reef, Australia. Growth rates were measured at three different depths (5, 10, and 15 m) over 2 yr (2012-2014) assessing both seasonal and inter-annual variability. Results of this study were compared to equivalent measurements made in 1980-1982 at the same location. To assist in understanding inter-annual variability in coral growth, we also examined annual growth bands from massive Porites providing continuous growth and records of flooding history for Davies Reef over the period 1979-2012. Linear extension rates of A. muricata were substantially (11-62%) lower in 2012-2014 compared to 1980-1982, especially at 10 and 15 m depths. These declines in growth coincide with a + 0.14 °C change in annual mean temperature. For massive Porites, however, calcification rates were highly variable among years and there was no discernible long-term change in growth despite sustained increases in temperature of 0.064 °C per decade. Apparent differences in the growth rates of Acropora between 1980-1982 and 2012-2014 may reflect inter-annual variation in coral growth (as seen for massive Porites), though it is known branching Acropora is much more sensitive to changing environmental conditions than massive corals. There are persistent issues in assessing the sensitivities of branching corals to environmental change due to limited capacity for retrospective analyses of growth, but given their disproportionate contribution to habitat complexity and reef structure, it is critical to ascertain

  7. Late quaternary uplift and subsidence of the west coast of Tanna, south Vanuatu, southwest Pacific: U-Th ages of raised coral reefs in the Median Sedimentary Basin

    International Nuclear Information System (INIS)

    Neef, G.; Zhao, J.X.; Collerson, K.D.; Zhang, F.S.

    2003-01-01

    Twelve Late Quaternary TIMS U-Th ages are reported here from 10 coral samples collected in situ from five transgressive coral/algal raised reefs (height: max. 113m, min. 8m) and two raised lagoonal deposits (height: max. 18 m, min. 8 m) along and near the west coast of Tanna, which lies in the Median Sedimentary Basin of South Vanuatu, southwest Pacific. These reefs and raised lagoonal deposits represent several age groups: (i) 215ka (marine oxygen-isotope stage 7) penultimate interglacial (highest elevation and oldest); (ii) one lagoonal deposit of ca 127 ka (marine oxygen-isotope stage 5e); (iii) three last interglacial reefs with ages 102, 89 and 81 ka (representing marine oxygen-isotope stages 5c, 5b and 5a, respectively, of the latter part of the last interglacial); (iv) a lagoonal deposit with a 92 ka age (5b); and (v) a Holocene reef (age >5.7-5.0 ka) (lowest elevation and youngest). A ca 4.9 ka regressive reef (at elevation of 1.5 m above sea-level) is consistent with an island-wide 6.5m uplift (probably largely coseismic), and a probable further island-wide uplift-occurred in the late Holocene. The U-series ages taken together with the heights of transgressive reefs show that uplift since 215 ka was, on average, at -0.52 mm/y, although since 5 ka the uplift rate was, on average, ∼1.6 mm/y (the assumption being that a 1.5 m above sea-level reef has a coseismic origin) Elevation of transgressive reefs 5a, 5b and 5c and their ages indicates an island-wide subsidence during the period ?124-89 ka (i.e. Late Quaternary uplift/subsidence was jerky). Late Quaternary uplift/subsidence on the northwest coast of Tanna is considered to be due to irregular thickness of crust being subducted beneath Tanna. Copyright (2003) Geological Society of Australia

  8. The growth of coral reef science in the Gulf: a historical perspective.

    Science.gov (United States)

    Burt, John A

    2013-07-30

    Coral reef science has grown exponentially in recent decades in the Gulf. Analysis of literature from 1950 to 2012 identified 270 publications on coral reefs in the Gulf, half of which were published in just the past decade. This paper summarizes the growth and evolution of coral reef science in the Gulf by examining when, where and how research has been conducted on Gulf reefs, who conducted that research, and what themes and taxa have dominated scientific interest. The results demonstrate that there has been significant growth in our understanding of the valuable coral reefs of the Gulf, but also highlight the fact that we are documenting an increasingly degraded ecosystem. Reef scientists must make a concerted effort to improve dialogue with regional reef management and decision-makers if we are to stem the tide of decline in coral reefs in the Gulf. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Remote coral reefs can sustain high growth potential and may match future sea-level trends.

    Science.gov (United States)

    Perry, Chris T; Murphy, Gary N; Graham, Nicholas A J; Wilson, Shaun K; Januchowski-Hartley, Fraser A; East, Holly K

    2015-12-16

    Climate-induced disturbances are contributing to rapid, global-scale changes in coral reef ecology. As a consequence, reef carbonate budgets are declining, threatening reef growth potential and thus capacity to track rising sea-levels. Whether disturbed reefs can recover their growth potential and how rapidly, are thus critical research questions. Here we address these questions by measuring the carbonate budgets of 28 reefs across the Chagos Archipelago (Indian Ocean) which, while geographically remote and largely isolated from compounding human impacts, experienced severe (>90%) coral mortality during the 1998 warming event. Coral communities on most reefs recovered rapidly and we show that carbonate budgets in 2015 average +3.7 G (G = kg CaCO3 m(-2) yr(-1)). Most significantly the production rates on Acropora-dominated reefs, the corals most severely impacted in 1998, averaged +8.4 G by 2015, comparable with estimates under pre-human (Holocene) disturbance conditions. These positive budgets are reflected in high reef growth rates (4.2 mm yr(-1)) on Acropora-dominated reefs, demonstrating that carbonate budgets on these remote reefs have recovered rapidly from major climate-driven disturbances. Critically, these reefs retain the capacity to grow at rates exceeding measured regional mid-late Holocene and 20th century sea-level rise, and close to IPCC sea-level rise projections through to 2100.

  10. Coral reefs of the turbid inner-shelf of the Great Barrier Reef, Australia: An environmental and geomorphic perspective on their occurrence, composition and growth

    Science.gov (United States)

    Browne, N. K.; Smithers, S. G.; Perry, C. T.

    2012-10-01

    Investigations of the geomorphic and sedimentary context in which turbid zone reefs exist, both in the modern and fossil reef record, can inform key ecological debates regarding species tolerances and adaptability to elevated turbidity and sedimentation. Furthermore, these investigations can address critical geological and palaeoecological questions surrounding longer-term coral-sediment interactions and reef growth histories. Here we review current knowledge about turbid zone reefs from the inner-shelf regions of the Great Barrier Reef (GBR) in Australia to consider these issues and to evaluate reef growth in the period prior to and post European settlement. We also consider the future prospects of these reefs under reported changing water quality regimes. Turbid zone reefs on the GBR are relatively well known compared to those in other reef regions. They occur within 20 km of the mainland coast where reef development may be influenced by continual or episodic terrigenous sediment inputs, fluctuating salinities (24-36 ppt), and reduced water quality through increased nutrient and pollutant delivery from urban and agricultural runoff. Individually, and in synergy, these environmental conditions are widely viewed as unfavourable for sustained and vigorous coral reef growth, and thus these reefs are widely perceived as marginal compared to clear water reef systems. However, recent research has revealed that this view is misleading, and that in fact many turbid zone reefs in this region are resilient, exhibit relatively high live coral cover (> 30%) and have distinctive community assemblages dominated by fast growing (Acropora, Montipora) and/or sediment tolerant species (Turbinaria, Goniopora, Galaxea, Porites). Palaeoecological reconstructions based on the analysis of reef cores show that community assemblages are relatively stable at millennial timescales, and that many reefs are actively accreting (average 2-7 mm/year) where accommodation space is available

  11. Crustose coralline algae can suppress macroalgal growth and recruitment on Hawaiian coral reefs

    NARCIS (Netherlands)

    Vermeij, M.J.A.; Dailer, M.L.; Smith, C.M.

    2011-01-01

    Crustose coralline algae are important components of tropical reef communities because they promote successful settlement by corals and contribute to solidification of the reef framework. We show experimentally that crustose coralline algae are also capable of suppressing the growth and recruitment

  12. Otolith growth of Springer's demoiselle, Chrysiptera springeri (Pomacentridae, Allen & Lubbock), on a protected and non-protected coral reef

    DEFF Research Database (Denmark)

    Retzel, A.; Hansen, A.D.; Grønkjær, P.

    2007-01-01

    The structural complexity of coral reefs is important for their function as shelter and feeding habitats for coral reef fishes, but physical disturbance by human activities often reduce complexity of the reefs by selectively destroying fragile and more complex coral species. The damselfish Springer......'s demoiselle Chrysiptera springeri primarily utilize complex coral heads for shelter and are hence vulnerable to human disturbance. In order to evaluate the potential effect of habitat degradation on juvenile fish growth, coral reef cover, fish age at settling and otolith growth, juvenile Springer's demoiselle...... was investigated on a protected and non-protected coral reef in Darvel Bay, Borneo. The protected reef had higher coverage of complex branching corals and exhibited a more complex 3-dimensional structure than the non-protected reef. Springer's demoiselle settled at the same age on non-protected and protected reefs...

  13. Accretion history and stratigraphy of mid-Holocene coral reefs from Southeast Florida, USA

    Science.gov (United States)

    Stathakopoulos, A.; Riegl, B. M.; Swart, P. K.

    2013-05-01

    The southeast Florida shelf is a well-studied coral reef region previously used in studies of late Quaternary sea-level, reef geomorphology, and paleoecology in the sub-tropical Atlantic. Situated on the shelf is the southeast Florida continental reef tract; a ~125 km long Holocene fringing/barrier coral reef complex, composed of three shore-parallel linear reefs ('outer', 'middle', and 'inner' reefs) of varying age. Since few detailed stratigraphic descriptions exist, drill cores were extracted to further understand the composition, character, and radiometric ages of reef material in order to reconstruct the accretion history. Sixteen reef cores from the shallow inner reef were collected along and across the reef axes and were combined with lidar bathymetric data for stratigraphic and geomorphologic analyses. Macroscopic and microscopic (petrographic thin sections) examinations of reef clasts were performed to identify coral and reef infauna species compositions, diagenetic facies, and taphonomic features for interpretation of former reef environments/zonation. The southeast Florida continental reef tract was characterized by dynamic reef terminations, backstepping, and re-initiation in response to post-glacial sea-level rise and flooding of topography suitable for reef initiation and growth. Results suggest that the outer reef accreted from ~10.6-8.0 ka cal BP, the middle reef from at least ~5.8-3.7 ka cal BP, and the inner reef from ~7.8-5.5 ka cal BP. The outer reef is the best-developed reef, followed by the inner reef, while the middle reef apparently has relatively little framework buildup. New data from this study and a lack of significant age overlaps confirm that reef backstepping from the outer to the inner reef occurred within a few hundred years after outer reef termination. This is consistent with temporal and spatial scales reported from backstepped reefs in St. Croix and Puerto Rico. The cause of the backstep is still unknown however some studies

  14. Molecular-beam epitaxial growth and characterization of quaternary III-nitride compounds

    International Nuclear Information System (INIS)

    Monroy, E.; Gogneau, N.; Enjalbert, F.; Fossard, F.; Jalabert, D.; Bellet-Amalric, E.; Dang, Le Si; Daudin, B.

    2003-01-01

    We report on the controlled growth and characterization of quaternary AlGaInN compounds by plasma-assisted molecular beam epitaxy. Two-dimensional growth is achieved with a monolayer of In segregating at the growth front. In incorporation is hindered by increasing growth temperature and Al mole fraction, which is explained by the lower binding energy of InN compared to GaN and AlN. The mosaicity of the layers is determined by the substrate quality, whereas the alloy disorder increases with the Al content, independent of the In mole fraction. Room temperature photoluminescence is dominated by a narrow band-edge emission, whose Stokes shift and activation energy increase with the In content. This behavior is interpreted in terms of carrier localization in self-formed alloy inhomogeneities. An In-related band bowing parameter of 2.5 eV has been estimated

  15. Plastic growth of the herbivorous reef fish Sparisoma viride: field evidence for a trade-off between growth and reproduction

    NARCIS (Netherlands)

    van Rooij, J.M.; Bruggemann, J.H.; Videler, J.J.; Breeman, A.M.

    The growth of different Life phases and social categories of the protogynous parrotfish Sparisoma viride was studied on a fringing reef on Bonaire (Netherlands Antilles) using mark-recapture procedures and by taking repeated stereographic measurements of free-swimming fish. Weight-growth was best

  16. Growth of quaternary InAlGaN barrier with ultrathin thickness for HEMT application

    Science.gov (United States)

    Li, Zhonghui; Li, Chuanhao; Peng, Daqing; Zhang, Dongguo; Dong, Xun; Pan, Lei; Luo, Weike; Li, Liang; Yang, Qiankun

    2018-06-01

    Quaternary InAlGaN barriers with thickness of 7 nm for HEMT application were grown on 3-inch semi-insulating 4H-SiC substrates by metal organic chemical vapor deposition (MOCVD). Focused on growth mechanism of the InAlGaN barrier, the surface morphology and characteristics of InAlGaN/AlN/GaN heterostructures were studied with different growth parameters, including the temperature, Al/Ga ratio and chamber pressure. Among the as-grown samples, high electron mobility is consistent with smooth surface morphology, while high crystalline quality of the quaternary barrier is confirmed by measurements of Photoluminescence (PL) and Mercury-probe Capacity-Voltage (C-V). The recommended heterostructures without SiN passivation is characterized by mobility of 1720 cm2/(V·s), 2DEG density of 1.71*1013 cm-2, sheet resistance of about 210 Ω/□ with a smooth surface morphology and moderate tensile state, specially applied for microwave devices.

  17. Global warming and coral reefs: modelling the effect of temperature on Acropora palmata colony growth.

    Science.gov (United States)

    Crabbe, M James C

    2007-08-01

    Data on colony growth of the branching coral Acropora palmata from fringing reefs off Discovery Bay on the north coast of Jamaica have been obtained over the period 2002-2007 using underwater photography and image analysis by both SCUBA and remotely using an ROV incorporating twin lasers. Growth modelling shows that while logarithmic growth is an approximate model for growth, a 3:3 rational polynomial function provides a significantly better fit to growth data for this coral species. Over the period 2002-2007, involving several cycles of sea surface temperature (SST) change, the rate of growth of A. palmata was largely proportional to rate of change of SST, with R(2)=0.935. These results have implications for the influence of global warming and climate change on coral reef ecosystems.

  18. Coral Reef Functioning Along a Cross‐shelf Environmental Gradient: Abiotic and Biotic Drivers of Coral Reef Growth in the Red Sea

    KAUST Repository

    Roik, Anna

    2016-06-01

    Despite high temperature and salinity conditions that challenge reef growth in other oceans, the Red Sea maintains amongst the most biodiverse and productive coral reefs worldwide. It is therefore an important region for the exploration of coral reef functioning, and expected to contribute valuable insights towards the understanding of coral reefs in challenging environments. This dissertation assessed the baseline variability of in situ abiotic conditions (temperature, dissolved oxygen, pH, and total alkalinity, among others) in the central Red Sea and highlights these environmental regimes in a global context. Further, focus was directed on biotic factors (biofilm community dynamics, calcification and bioerosion), which underlie reef growth processes and are crucial for maintaining coral reef functioning and ecosystem services. Using full‐year data from an environmental cross‐shelf gradient, the dynamic interplay of abiotic and biotic factors was investigated. In situ observations demonstrate that central Red Sea coral reefs were highly variable on spatial, seasonal, and diel scales, and exhibited comparably high temperature, high salinity, and low dissolved oxygen levels, which on the one hand reflect future ocean predictions. Under these conditions epilithic bacterial and algal assemblages were mainly driven by variables (i.e., temperature, salinity, dissolved oxygen) which are predicted to change strongly in the progression of global climate change, implying an influential bottom up effect on reef‐building communities. On the other hand, measured alkalinity and other carbonate chemistry value were close to the estimates of preindustrial global ocean surface water and thus in favor of reef growth processes. Despite this beneficial carbonate chemistry, calcification and carbonate budgets in the reefs were not higher than in other coral reef regions. In this regard, seasonal calcification patterns suggest that summer temperatures may be exceeding the optima

  19. Integrating physiological and biomechanical drivers of population growth over environmental gradients on coral reefs.

    Science.gov (United States)

    Madin, Joshua S; Hoogenboom, Mia O; Connolly, Sean R

    2012-03-15

    Coral reefs exhibit marked spatial and temporal variability, and coral reef organisms exhibit trade-offs in functional traits that influence demographic performance under different combinations of abiotic environmental conditions. In many systems, trait trade-offs are modelled using an energy and/or nutrient allocation framework. However, on coral reefs, differences in biomechanical vulnerability have major demographic implications, and indeed are believed to play an essential role in mediating species coexistence because highly competitive growth forms are vulnerable to physical dislodgment events that occur with high frequency (e.g. annual summer storms). Therefore, an integrated energy allocation and biomechanics framework is required to understand the effect of physical environmental gradients on species' demographic performance. However, on coral reefs, as in most ecosystems, the effects of environmental conditions on organisms are measured in different currencies (e.g. lipid accumulation, survival and number of gametes), and thus the relative contributions of these effects to overall capacity for population growth are not readily apparent. A comprehensive assessment of links between the environment and the organism, including those mediated by biomechanical processes, must convert environmental effects on individual-level performance (e.g. survival, growth and reproduction) into a common currency that is relevant to the capacity to contribute to population growth. We outline such an approach by considering the population-level performance of scleractinian reef corals over a hydrodynamic gradient, with a focus on the integrating the biomechanical determinants of size-dependent coral colony dislodgment as a function of flow, with the effects of flow on photosynthetic energy acquisition and respiration.

  20. Coral reef growth in an era of rapidly rising sea level: predictions and suggestions for long-term research

    Energy Technology Data Exchange (ETDEWEB)

    Buddemeier, R W; Smith, S V

    1988-01-01

    Coral reef growth is intimately linked to sea level. It has been postulated that over the next century, sea level will rise at a probable average rate of 15 mm/year, in response to fossil fuel emissions, heating, and melting of the Antarctic ice cap. This predicted rate of sea level rise is five times the present modal rate of vertical accretion on coral reef flats and 50% greater than the maximum vertical accretion rates apparently attained by coral reefs. We use these predictions and observations to offer the following hypothesis for reef growth over the next century. The vertical accretion rates of protected reef flats will accelerate from the present modal rate up to the maximum rate, in response to the more rapidly rising sea level. This more rapid vertical accretion rate will be insufficient to keep up with sea level rise, if present predictions prove to be correct. Less protected reef flats will slow their rate of growth as they become inundated and subjected to erosion by progressively larger waves. This projected sea level rise and postulated reef response will provide an opportunity for long- term studies of the response of coral reef systems to a predictable and measurable forcing function.

  1. Surviving coral bleaching events: porites growth anomalies on the Great Barrier Reef.

    Science.gov (United States)

    Cantin, Neal E; Lough, Janice M

    2014-01-01

    Mass coral bleaching affected large parts of the Great Barrier Reef (GBR) in 1998 and 2002. In this study, we assessed if signatures of these major thermal stress events were recorded in the growth characteristics of massive Porites colonies. In 2005 a suite of short (bleaching. Sites included inshore (Nelly Bay, Pandora Reef), annually affected by freshwater flood events, midshelf (Rib Reef), only occasionally affected by freshwater floods and offshore (Myrmidon Reef) locations primarily exposed to open ocean conditions. Annual growth characteristics (extension, density and calcification) were measured in 144 cores from 79 coral colonies and analysed over the common 24-year period, 1980-2003. Visual examination of the annual density bands revealed growth hiatuses associated with the bleaching years in the form of abrupt decreases in annual linear extension rates, high density stress bands and partial mortality. The 1998 mass-bleaching event reduced Porites calcification by 13 and 18% on the two inshore locations for 4 years, followed by recovery to baseline calcification rates in 2002. Evidence of partial mortality was apparent in 10% of the offshore colonies in 2002; however no significant effects of the bleaching events were evident in the calcification rates at the mid shelf and offshore sites. These results highlight the spatial variation of mass bleaching events and that all reef locations within the GBR were not equally stressed by the 1998 and 2002 mass bleaching events, as some models tend to suggest, which enabled recovery of calcification on the GBR within 4 years. The dynamics in annual calcification rates and recovery displayed here should be used to improve model outputs that project how coral calcification will respond to ongoing warming of the tropical oceans.

  2. Growth of the tropical zoanthid Palythoa caribaeorum (Cnidaria: Anthozoa on reefs in northeastern Brazil

    Directory of Open Access Journals (Sweden)

    JANINE F. SILVA

    2015-06-01

    Full Text Available In Brazilian reefs, zoanthids, especially Palythoa caribaeorum are fundamental for structuring the local benthic community. The objective of this study was to determine the growth rate of P. caribaeorum, and to assess the influence of the site (different beaches, season (dry and wet, location (intertidal or infralittoral zones, and human pressure associated with tourism. For one year we monitored the cover of P. caribaeorum in transects and focused on 20 colonies. We cut off a square (100 cm2 from the central part of the colony and monitored the bare area for four months in each season. The average growth rates varied from 0.015 and 0.021 cm.day-1. The rate was homogeneous in all localities, and there was no influence from colony site, location, or touristic visitation, showing that the growth velocity may be an intrinsic characteristic of the species, with a strong genetic component. The growth rate of P. caribaeorum differed among months, and peaked in the first month after injury. The average cover varied from 6.2 to 22.9% and was lower on the reef visited by tourists. The present study corroborates the hypothesis that P. caribaeorum is important for coastal reef dynamics due to its fast and continuous growth.

  3. Growth of the tropical zoanthid Palythoa caribaeorum (Cnidaria: Anthozoa) on reefs in northeastern Brazil.

    Science.gov (United States)

    Silva, Janine F; Gomes, Paula B; Santana, Erika C; Silva, João M; Lima, Érica P; Santos, Andre M M; Pérez, Carlos D

    2015-01-01

    In Brazilian reefs, zoanthids, especially Palythoa caribaeorum are fundamental for structuring the local benthic community. The objective of this study was to determine the growth rate of P. caribaeorum, and to assess the influence of the site (different beaches), season (dry and wet), location (intertidal or infralittoral zones), and human pressure associated with tourism. For one year we monitored the cover of P. caribaeorum in transects and focused on 20 colonies. We cut off a square (100 cm2) from the central part of the colony and monitored the bare area for four months in each season. The average growth rates varied from 0.015 and 0.021 cm.day(-1). The rate was homogeneous in all localities, and there was no influence from colony site, location, or touristic visitation, showing that the growth velocity may be an intrinsic characteristic of the species, with a strong genetic component. The growth rate of P. caribaeorum differed among months, and peaked in the first month after injury. The average cover varied from 6.2 to 22.9% and was lower on the reef visited by tourists. The present study corroborates the hypothesis that P. caribaeorum is important for coastal reef dynamics due to its fast and continuous growth.

  4. Tolerance to quaternary ammonium compound disinfectants may enhance growth of Listeria monocytogenes in the food industry.

    Science.gov (United States)

    Møretrø, Trond; Schirmer, Bjørn C T; Heir, Even; Fagerlund, Annette; Hjemli, Pernille; Langsrud, Solveig

    2017-01-16

    The antibacterial effect of disinfectants is crucial for the control of Listeria monocytogenes in food processing environments. Tolerance of L. monocytogenes to sublethal levels of disinfectants based on quaternary ammonium compounds (QAC) is conferred by the resistance determinants qacH and bcrABC. The presence and distribution of these genes have been anticipated to have a role in the survival and growth of L. monocytogenes in food processing environments where QAC based disinfectants are in common use. In this study, a panel of 680 L. monocytogenes from nine Norwegian meat- and salmon processing plants were grouped into 36 MLVA profiles. The presence of qacH and bcrABC was determined in 101 isolates from the 26 most common MLVA profiles. Five MLVA profiles contained qacH and two contained bcrABC. Isolates with qacH and bcrABC showed increased tolerance to the QAC Benzalkonium chloride (BC), with minimal inhibitory concentrations (MICs) of 5-12, 10-13 and 100ppm). A sample with lower BC concentrations (14ppm of chain length C-12 and 2.7ppm of chain length C-14) inhibited growth of L. monocytogenes not containing bcrABC or qacH, compared to strains with these genes. The study has shown that L. monocytogenes harbouring the QAC resistance genes qacH and bcrABC are prevalent in the food industry and that residuals of QAC may be present in concentrations after sanitation in the industry that result in a growth advantage for bacteria with such resistance genes. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Do otolith increments allow correct inferences about age and growth of coral reef fishes?

    Science.gov (United States)

    Booth, D. J.

    2014-03-01

    Otolith increment structure is widely used to estimate age and growth of marine fishes. Here, I test the accuracy of the long-term otolith increment analysis of the lemon damselfish Pomacentrus moluccensis to describe age and growth characteristics. I compare the number of putative annual otolith increments (as a proxy for actual age) and widths of these increments (as proxies for somatic growth) with actual tagged fish-length data, based on a 6-year dataset, the longest time course for a coral reef fish. Estimated age from otoliths corresponded closely with actual age in all cases, confirming annual increment formation. However, otolith increment widths were poor proxies for actual growth in length [linear regression r 2 = 0.44-0.90, n = 6 fish] and were clearly of limited value in estimating annual growth. Up to 60 % of the annual growth variation was missed using otolith increments, suggesting the long-term back calculations of otolith growth characteristics of reef fish populations should be interpreted with caution.

  6. Impact of herbivore identity on algal succession and coral growth on a Caribbean reef.

    Directory of Open Access Journals (Sweden)

    Deron E Burkepile

    2010-01-01

    Full Text Available Herbivory is an important top-down force on coral reefs that regulates macroalgal abundance, mediates competitive interactions between macroalgae and corals, and provides resilience following disturbances such as hurricanes and coral bleaching. However, reductions in herbivore diversity and abundance via disease or over-fishing may harm corals directly and may indirectly increase coral susceptibility to other disturbances.In two experiments over two years, we enclosed equivalent densities and masses of either single-species or mixed-species of herbivorous fishes in replicate, 4 m(2 cages at a depth of 17 m on a reef in the Florida Keys, USA to evaluate the effects of herbivore identity and species richness on colonization and development of macroalgal communities and the cascading effects of algae on coral growth. In Year 1, we used the redband parrotfish (Sparisoma aurofrenatum and the ocean surgeonfish (Acanthurus bahianus; in Year 2, we used the redband parrotfish and the princess parrotfish (Scarus taeniopterus. On new substrates, rapid grazing by ocean surgeonfish and princess parrotfish kept communities in an early successional stage dominated by short, filamentous algae and crustose coralline algae that did not suppress coral growth. In contrast, feeding by redband parrotfish allowed an accumulation of tall filaments and later successional macroalgae that suppressed coral growth. These patterns contrast with patterns from established communities not undergoing primary succession; on established substrates redband parrotfish significantly reduced upright macroalgal cover while ocean surgeonfish and princess parrotfish allowed significant increases in late successional macroalgae.This study further highlights the importance of biodiversity in affecting ecosystem function in that different species of herbivorous fishes had very different impacts on reef communities depending on the developmental stage of the community. The species

  7. Macroalgae Decrease Growth and Alter Microbial Community Structure of the Reef-Building Coral, Porites astreoides

    Science.gov (United States)

    Vega Thurber, Rebecca; Burkepile, Deron E.; Correa, Adrienne M. S.; Thurber, Andrew R.; Shantz, Andrew A.; Welsh, Rory; Pritchard, Catharine; Rosales, Stephanie

    2012-01-01

    With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites astreoides was placed in competition with five species of macroalgae. Macroalgal contact increased variance in the coral-associated microbial community, and two algal species significantly altered microbial community composition. All macroalgae caused the disappearance of a γ-proteobacterium previously hypothesized to be an important mutualist of P. astreoides. Macroalgal contact also triggered: 1) increases or 2) decreases in microbial taxa already present in corals, 3) establishment of new taxa to the coral microbiome, and 4) vectoring and growth of microbial taxa from the macroalgae to the coral. Furthermore, macroalgal competition decreased coral growth rates by an average of 36.8%. Overall, this study found that competition between corals and certain species of macroalgae leads to an altered coral microbiome, providing a potential mechanism by which macroalgae-coral interactions reduce coral health and lead to coral loss on impacted reefs. PMID:22957055

  8. Macroalgae decrease growth and alter microbial community structure of the reef-building coral, Porites astreoides.

    Directory of Open Access Journals (Sweden)

    Rebecca Vega Thurber

    Full Text Available With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites astreoides was placed in competition with five species of macroalgae. Macroalgal contact increased variance in the coral-associated microbial community, and two algal species significantly altered microbial community composition. All macroalgae caused the disappearance of a γ-proteobacterium previously hypothesized to be an important mutualist of P. astreoides. Macroalgal contact also triggered: 1 increases or 2 decreases in microbial taxa already present in corals, 3 establishment of new taxa to the coral microbiome, and 4 vectoring and growth of microbial taxa from the macroalgae to the coral. Furthermore, macroalgal competition decreased coral growth rates by an average of 36.8%. Overall, this study found that competition between corals and certain species of macroalgae leads to an altered coral microbiome, providing a potential mechanism by which macroalgae-coral interactions reduce coral health and lead to coral loss on impacted reefs.

  9. Impact of diurnal temperature fluctuations on larval settlement and growth of the reef coral Pocillopora damicornis

    Science.gov (United States)

    Jiang, Lei; Sun, You-Fang; Zhang, Yu-Yang; Zhou, Guo-Wei; Li, Xiu-Bao; McCook, Laurence J.; Lian, Jian-Sheng; Lei, Xin-Ming; Liu, Sheng; Cai, Lin; Qian, Pei-Yuan; Huang, Hui

    2017-12-01

    Diurnal fluctuations in seawater temperature are ubiquitous on tropical reef flats. However, the effects of such dynamic temperature variations on the early stages of corals are poorly understood. In this study, we investigated the responses of larvae and new recruits of Pocillopora damicornis to two constant temperature treatments (29 and 31 °C) and two diurnally fluctuating treatments (28-31 and 30-33 °C with daily means of 29 and 31 °C, respectively) simulating the 3 °C diel oscillations at 3 m depth on the Luhuitou fringing reef (Sanya, China). Results showed that the thermal stress on settlement at 31 °C was almost negated by the fluctuating treatment. Further, neither elevated temperature nor temperature fluctuations caused bleaching responses in recruits, while the maximum excitation pressure over photosystem II (PSII) was reduced under fluctuating temperatures. Although early growth and development were highly stimulated at 31 °C, oscillations of 3 °C had little effects on budding and lateral growth at either mean temperature. Nevertheless, daytime encounters with the maximum temperature of 33 °C in fluctuating 31 °C elicited a notable reduction in calcification compared to constant 31 °C. These results underscore the complexity of the effects caused by diel temperature fluctuations on early stages of corals and suggest that ecologically relevant temperature variability could buffer warming stress on larval settlement and dampen the positive effects of increased temperatures on coral growth.

  10. Seasonal and life-phase related differences in growth in Scarus ferrugineus on a southern Red Sea fringing reef

    NARCIS (Netherlands)

    Afeworki, Y.; Videler, J. J.; Berhane, Y. H.; Bruggemann, J. H.

    Temporal trends in growth of the rusty parrotfish Scarus ferrugineus were studied on a southern Red Sea fringing reef that experiences seasonal changes in environmental conditions and benthic algal resources. Length increment data from tagging and recapture were compared among periods and sexes and

  11. Impact of diurnal temperature fluctuations on larval settlement and growth of the reef coral Pocillopora damicornis

    Directory of Open Access Journals (Sweden)

    L. Jiang

    2017-12-01

    Full Text Available Diurnal fluctuations in seawater temperature are ubiquitous on tropical reef flats. However, the effects of such dynamic temperature variations on the early stages of corals are poorly understood. In this study, we investigated the responses of larvae and new recruits of Pocillopora damicornis to two constant temperature treatments (29 and 31 °C and two diurnally fluctuating treatments (28–31 and 30–33 °C with daily means of 29 and 31 °C, respectively simulating the 3 °C diel oscillations at 3 m depth on the Luhuitou fringing reef (Sanya, China. Results showed that the thermal stress on settlement at 31 °C was almost negated by the fluctuating treatment. Further, neither elevated temperature nor temperature fluctuations caused bleaching responses in recruits, while the maximum excitation pressure over photosystem II (PSII was reduced under fluctuating temperatures. Although early growth and development were highly stimulated at 31 °C, oscillations of 3 °C had little effects on budding and lateral growth at either mean temperature. Nevertheless, daytime encounters with the maximum temperature of 33 °C in fluctuating 31 °C elicited a notable reduction in calcification compared to constant 31 °C. These results underscore the complexity of the effects caused by diel temperature fluctuations on early stages of corals and suggest that ecologically relevant temperature variability could buffer warming stress on larval settlement and dampen the positive effects of increased temperatures on coral growth.

  12. Potential Costs of Acclimatization to a Warmer Climate: Growth of a Reef Coral with Heat Tolerant vs. Sensitive Symbiont Types

    OpenAIRE

    Jones, Alison; Berkelmans, Ray

    2010-01-01

    One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae) genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Kepp...

  13. Trade-off between increased survival and reduced growth for blue mussels living on Pacific oyster reefs

    DEFF Research Database (Denmark)

    Eschweiler, Nina; Christensen, Helle Torp

    2011-01-01

    Pacific oysters Crassostrea gigas (Thunberg 1793) have been introduced into the Wadden Sea (North Sea, Germany) in the mid of the 1980s and have invaded native blue mussel Mytilus edulis (L.) beds. The latter turned into oyster reefs where mussels seem to be relegated to the bottom in between...... the much larger oysters. By combining field and laboratory experiments, we reveal how mussels react to cohabitation with the invasive oysters. Mussels subjected to direct contact with crabs Carcinus maenas migrate from top to bottom positions between oysters in both field and laboratory experiments within...... 22days. Shell growth was significantly reduced for mussels placed on the bottom compared to mussels at the top of an oyster reef. Condition index was lower for mussels on the bottom of the reef irrespective of whether placed between dead or living oysters. We conclude that mussels experience a trade...

  14. Comparative Allometric Growth of the Mimetic Ephippid Reef Fishes Chaetodipterus faber and Platax orbicularis.

    Directory of Open Access Journals (Sweden)

    Breno Barros

    Full Text Available Mimesis is a relatively widespread phenomenon among reef fish, but the ontogenetic processes relevant for mimetic associations in fish are still poorly understood. In the present study, the allometric growth of two allopatric leaf-mimetic species of ephippid fishes, Chaetodipterus faber from the Atlantic and Platax orbicularis from the Indo-Pacific, was analyzed using ten morphological variables. The development of fins was considered owing to the importance of these structures for mimetic behaviors during early life stages. Despite the anatomical and behavioral similarities in both juvenile and adult stages, C. faber and P. orbicularis showed distinct patterns of growth. The overall shape of C. faber transforms from a rounded-shape in mimetic juveniles to a lengthened profile in adults, while in P. orbicularis, juveniles present an oblong profile including dorsal and anal fins, with relative fin size diminishing while the overall profile grows rounder in adults. Although the two species are closely-related, the present results suggest that growth patterns in C. faber and P. orbicularis are different, and are probably independent events in ephippids that have resulted from similar selective processes.

  15. Potential costs of acclimatization to a warmer climate: growth of a reef coral with heat tolerant vs. sensitive symbiont types.

    Directory of Open Access Journals (Sweden)

    Alison Jones

    Full Text Available One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change.

  16. Potential Costs of Acclimatization to a Warmer Climate: Growth of a Reef Coral with Heat Tolerant vs. Sensitive Symbiont Types

    Science.gov (United States)

    Jones, Alison; Berkelmans, Ray

    2010-01-01

    One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae) genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change. PMID:20454653

  17. Potential costs of acclimatization to a warmer climate: growth of a reef coral with heat tolerant vs. sensitive symbiont types.

    Science.gov (United States)

    Jones, Alison; Berkelmans, Ray

    2010-05-03

    One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae) genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change.

  18. Sediment and Nutrient Sources as well as Interspecific Competition Control Growth of 2 Common Species of Coral Reef Macroalgae

    Science.gov (United States)

    Moore, T.; Fong, P.; Cuker, B.

    2016-02-01

    Aquatic communities worldwide are increasingly subjected to multiple anthropogenic stressors that often result in shifts in structure and function. On coral reefs, human impacts have been associated with phase-shifts from coral to algal domination. We hypothesized that the proliferation of these algal communities, especially on fringing reefs, may be facilitated by human alterations in nutrient enrichment and input of sediments from developed watersheds, which may also influence competitive outcomes among dominant algal species. To evaluate how changes in these abiotic stressors as well as competition may affect the growth of 2 common species of calcifying coral reef algae, Galaxaura fasciculata and Padina boryana, we conducted 3 separate 2 factor mesocosm experiments modeling fringing reefs in Moorea, French Polynesia. In the first experiment, we varied sediment source (marine vs. terrestrial) and water column nutrients (ambient vs. enriched) for each species separately and measured growth after 7 days. While both algae grew faster in enriched compared to ambient nutrients, P. boryana performed best with marine sediment (+27% change in biomass) and G. fasciculata with terrestrial sediment (+14% change in biomass). Next, we varied sediment source (as above) as well as sediment nutrients (ambient/enriched) for each species. While P. boryana lost 44% biomass in the eutrophic terrestrial sediment treatment, G. fasciculata performed the best and gained 19% biomass. Finally, we varied competition (alone/together) and terrestrial sediment nutrients (ambient/enriched). Over the 7 day period, P. boryana lost 64% biomass when in competition with G. fasciculata in the enriched treatment while G. fasciculata gained 38% biomass when in competition with P. boryana in the ambient treatment. These results indicate that, while growth of both species of macroalgae was regulated by nutrients, sediments, and competition, each responded uniquely to these controlling factors.

  19. Uranium-series growth history of a Quaternary phosphatic crust from the Peruvian continental margin

    International Nuclear Information System (INIS)

    Kim, Kee Hyun; Burnett, W.C.

    1986-01-01

    A 20-mm-thick oriented phosphatic crust recovered together with its overlying (14 cm) and underlying (4 cm) associated sediment from the Peruvian sea floor has been analyzed in detail for uranium-series radionuclides in an attempt to determine its rate and direction of growth. Growth curves based upon 226 Ra and 230 Th ages show that this crust grew upward toward the sediment-water interface. Calculated growth rates in the range of 12-13 mm ka -1 are slightly higher but comparable to values previously reported. Crystallographical analyses of this phosphatic crust show a trend of decreasing unit-cell dimension a with sample age. The upward growth of a buried crust toward the sediment-water interface is consistent with results from recent pore-water studies of fluoride and phosphate in Peru shelf sediments. (orig.)

  20. The effect of nutrient enrichment on the growth, nucleic acid concentrations, and elemental stoichiometry of coral reef macroalgae.

    Science.gov (United States)

    Reef, Ruth; Pandolfi, John M; Lovelock, Catherine E

    2012-08-01

    The growth rate hypothesis (GRH) links growth rates with organism elemental stoichiometry. Support for the GRH was found for many animal species, but less so for plants. This is the first study to test the GRH in macroalgae. Tropical coral reef macroalgae from three lineages, Caulerpa serrulata (Chlorophyta), Laurencia intricata (Rhodophyta), and Sargassum polyphyllum (Phaeophyceae) were grown enriched with nitrogen or phosphorous and under control conditions at Heron Island on the Great Barrier Reef, Australia. Growth rate, photosynthesis, nucleic acid composition, and elemental stoichiometry were measured. Nutrient enrichment had positive effects on photosynthetic rates and on investment in RNA. However, growth rate was not correlated with either photosynthetic rates or RNA content; thus, we did not find support for the GRH in tropical macroalgae. Macroalgae, especially L. intricata, accumulated P to very high levels (>0.6% of dry weight). The growth rate response to tissue P concentrations was unimodal. Above 0.21%, P accumulation had negative effects on growth. Nitrogen was not stored, but evidence of futile cycling was observed. The capacity to store large amounts of P is probably an adaptation to the low and patchy nutrient environment of the tropical oceans.

  1. Future Reef Growth Can Mitigate Physical Impacts of Sea-Level Rise on Atoll Islands

    Science.gov (United States)

    Beetham, Edward; Kench, Paul S.; Popinet, Stéphane

    2017-10-01

    We present new detail on how future sea-level rise (SLR) will modify nonlinear wave transformation processes, shoreline wave energy, and wave driven flooding on atoll islands. Frequent and destructive wave inundation is a primary climate-change hazard that may render atoll islands uninhabitable in the near future. However, limited research has examined the physical vulnerability of atoll islands to future SLR and sparse information are available to implement process-based coastal management on coral reef environments. We utilize a field-verified numerical model capable of resolving all nonlinear wave transformation processes to simulate how future SLR will modify wave dissipation and overtopping on Funafuti Atoll, Tuvalu, accounting for static and accretionary reef adjustment morphologies. Results show that future SLR coupled with a static reef morphology will not only increase shoreline wave energy and overtopping but will fundamentally alter the spectral composition of shoreline energy by decreasing the contemporary influence of low-frequency infragravity waves. "Business-as-usual" emissions (RCP 8.5) will result in annual wave overtopping on Funafuti Atoll by 2030, with overtopping at high tide under mean wave conditions occurring from 2090. Comparatively, vertical reef accretion in response to SLR will prevent any significant increase in shoreline wave energy and mitigate wave driven flooding volume by 72%. Our results provide the first quantitative assessment of how effective future reef accretion can be at mitigating SLR-associated flooding on atoll islands and endorse active reef conservation and restoration for future coastal protection.

  2. Metal thin film growth on multimetallic surfaces: From quaternary metallic glass to binary crystal

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Dapeng [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    The work presented in this thesis mainly focuses on the nucleation and growth of metal thin films on multimetallic surfaces. First, we have investigated the Ag film growth on a bulk metallic glass surface. Next, we have examined the coarsening and decay of bilayer Ag islands on NiAl(110) surface. Third, we have investigated the Ag film growth on NiAl(110) surface using low-energy electron diffraction (LEED). At last, we have reported our investigation on the epitaxial growth of Ni on NiAl(110) surface. Some general conclusions can be drawn as follows. First, Ag, a bulk-crystalline material, initially forms a disordered wetting layer up to 4-5 monolayers on Zr-Ni-Cu-Al metallic glass. Above this coverage, crystalline 3D clusters grow, in parallel with the flatter regions. The cluster density increases with decreasing temperature, indicating that the conditions of island nucleation are far-from-equilibrium. Within a simple model where clusters nucleate whenever two mobile Ag adatoms meet, the temperature-dependence of cluster density yields a (reasonable) upper limit for the value of the Ag diffusion barrier on top of the Ag wetting layer of 0.32 eV. Overall, this prototypical study suggests that it is possible to grow films of a bulk-crystalline metal that adopt the amorphous character of a glassy metal substrate, if film thickness is sufficiently low. Next, the first study of coarsening and decay of bilayer islands has been presented. The system was Ag on NiAl(110) in the temperature range from 185 K to 250 K. The coarsening behavior, has some similarities to that seen in the Ag(110) homoepitaxial system studied by Morgenstern and co-workers. At 185 K and 205 K, coarsening of Ag islands follows a Smoluchowski ripening pathway. At 205 K and 250 K, the terrace diffusion limited Ostwald ripening dominants. The experimental observed temperature for the transition from SR to OR is 205 K. The SR exhibits anisotropic island diffusion and the OR exhibits 1D decay of island

  3. Pleistocene reef development in Bulukumba, South Sulawesi

    Directory of Open Access Journals (Sweden)

    Muhammad Imran Andi

    2017-01-01

    Full Text Available Quaternary reefs are commonly studied right now to explain climate change during that time. They act as a good archive of climate change, because their development is influenced by climate condition. The research area is located in the southern tip of Bulukumba Regency, South Sulawesi. The objective of this research is to define the development of the reef. Methods applied in this research are field survey of 4 line transects along reef cliff. Laboratory work is mostly on petrographic and biofacies analyses in order to reconstruct the reef development. Four reef biofacies have developed in this study namely 1 Coralgal framestone - wackestone, 2 Massive coral framestone facies, 3 Platylike coral Bindstone facies, and 4 Branching Coral Bafflestone facies. Based on the facies association and organism accumulation, the reefs are interpreted to be developed within a reef complex in a shallow marine environment.

  4. Occurrence, sources and transport of antibiotics in the surface water of coral reef regions in the South China Sea: Potential risk to coral growth

    International Nuclear Information System (INIS)

    Zhang, Ruijie; Zhang, Ruiling; Yu, Kefu; Wang, Yinghui; Huang, Xueyong; Pei, Jiying; Wei, Chaoshuai; Pan, Ziliang; Qin, Zhenjun; Zhang, Gan

    2018-01-01

    Laboratory research has indicated that antibiotics had negative effects on coral growth by disturbing natural microbiota; however, no field studies have reported antibiotic contamination levels and their influence on coral growth in natural coral reef regions (CRRs). This study investigated antibiotic occurrence and sources in the surface water from CRRs that have suffered from rapid coral degradation and evaluated their risk to coral growth. These regions are in the South China Sea, including four coastal and two offshore CRRs. The results show that 13 antibiotics were detected in the coastal CRRs with concentrations ranging from 10 −2 –10 0  ng L −1 , while 5 antibiotics occurred in offshore CRRs (300–950 km from the mainland), with concentrations ranging from 10 −2 to 10 −1  ng L −1 . Their concentrations decreased gradually from the coast to offshore in the transport process. However, Yongxing Island, which is approximately 300 km from the mainland, was an exception with relatively higher concentrations than the surrounding reefs because of the ever-increasing human activity on the island. The presence of anthropogenic contaminants antibiotics in CRRs may be a potential risk to coral growth. - Highlights: • The study first studied antibiotic contamination in seawater from coral reef regions. • Thirteen antibiotics were detected at the level of 10 −2 - 10 0  ng L −1 . • The antibiotic concentrations decreased gradually from the coast to offshore. • Higher concentrations were detected in one offshore reef with more human activities. • Potential risk of the antibiotics to the coral could be ruled out. - Antibiotic contamination level, sources and their potential risk to coral growth were first studied in the surface water of natural coral reef regions.

  5. Nitrification in reef corals

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Wafar, S.; David, J.J.

    . An estimate of the density of nitrifying bacteria on living corals can be made by comparing the nitrifying rates of bacterial cells and the rate of production of NO,-. Kaplan (1983) summarized the growth con- stants of marine nitrifying bacteria... Reef Con=. 3: 395-399. -, C. R. WILKINSON, V. p. VICENTE, J. M. MORELL, AND E. OTERO. 1988. Nitrate release by Carib- bean reef sponges. Limnol. Oceanogr. 33: 114- 120. CROSSLAND, C. J., AND D. J. BARNES. 1983. Dissolved nutrients and organic...

  6. Mesopredator trophodynamics on thermally stressed coral reefs

    Science.gov (United States)

    Hempson, Tessa N.; Graham, Nicholas A. J.; MacNeil, M. Aaron; Hoey, Andrew S.; Almany, Glenn R.

    2018-03-01

    Ecosystems are becoming vastly modified through disturbance. In coral reef ecosystems, the differential susceptibility of coral taxa to climate-driven bleaching is predicted to shift coral assemblages towards reefs with an increased relative abundance of taxa with high thermal tolerance. Many thermally tolerant coral species are characterised by low structural complexity, with reduced habitat niche space for the small-bodied coral reef fishes on which piscivorous mesopredators feed. This study used a patch reef array to investigate the potential impacts of climate-driven shifts in coral assemblages on the trophodynamics of reef mesopredators and their prey communities. The `tolerant' reef treatment consisted only of coral taxa of low susceptibility to bleaching, while `vulnerable' reefs included species of moderate to high thermal vulnerability. `Vulnerable' reefs had higher structural complexity, and the fish assemblages that established on these reefs over 18 months had higher species diversity, abundance and biomass than those on `tolerant' reefs. Fish assemblages on `tolerant' reefs were also more strongly influenced by the introduction of a mesopredator ( Cephalopholis boenak). Mesopredators on `tolerant' reefs had lower lipid content in their muscle tissue by the end of the 6-week experiment. Such sublethal energetic costs can compromise growth, fecundity, and survivorship, resulting in unexpected population declines in long-lived mesopredators. This study provides valuable insight into the altered trophodynamics of future coral reef ecosystems, highlighting the potentially increased vulnerability of reef fish assemblages to predation as reef structure declines, and the cost of changing prey availability on mesopredator condition.

  7. Quaternary coastal geology of Pernambuco State

    International Nuclear Information System (INIS)

    Dominguez, J.M.L.; Silva Pinto Bittencourt, A.C. da; Andrade Nery Leao, Z.M. de; Azevedo, A.E.G. de

    1990-01-01

    This paper presents a geological map of Quaternary deposits occuring along the coast of the State of Pernambuco. These deposits comprise: 1. two sets of beach-ridge terraces of Pleistocene (120,000 years B.P.) and Holocene (5,000 years B.P.) age; 2. paleolagoonal deposits (5,140-6,030 years B.P.); 3. sandstone and coralgal reefs with ages spanning from 1,830 to 5,170 years B.P.; and 4, alluvial, freshwater swamp, and coralgal reefs with ages spanning from 1,830 to 5,170 years B.P.; and 4. alluvial, freshwater swamp, and mangrove swamp deposits of Holocene age. Eighteen new radiocarbon dates of paleolagoonal deposits, sandstone reefs, coral, coralline algae, and vermetid gastropod incrustations are also reported herein. (author)

  8. Oceanic forcing of coral reefs.

    Science.gov (United States)

    Lowe, Ryan J; Falter, James L

    2015-01-01

    Although the oceans play a fundamental role in shaping the distribution and function of coral reefs worldwide, a modern understanding of the complex interactions between ocean and reef processes is still only emerging. These dynamics are especially challenging owing to both the broad range of spatial scales (less than a meter to hundreds of kilometers) and the complex physical and biological feedbacks involved. Here, we review recent advances in our understanding of these processes, ranging from the small-scale mechanics of flow around coral communities and their influence on nutrient exchange to larger, reef-scale patterns of wave- and tide-driven circulation and their effects on reef water quality and perceived rates of metabolism. We also examine regional-scale drivers of reefs such as coastal upwelling, internal waves, and extreme disturbances such as cyclones. Our goal is to show how a wide range of ocean-driven processes ultimately shape the growth and metabolism of coral reefs.

  9. Ages of subsurface stratigraphic intervals in the Quaternary of Enewetak Atoll, Marshall Islands

    Science.gov (United States)

    Szabo, B. J.; Tracey, J.I.; Goter, E.R.

    1985-01-01

    Drill cores of Enewetak Atoll, Marshall Islands, reveal six stratigraphic intervals, numbered in downward sequence, which represent vertical coral growth during Quaternary interglaciations. Radiocarbon dates indicate that the Holocene sea transgressed the emergent reef platform by about 8000 yr B.P. The reef grew rapidly upward (about 5 to 10 mm/yr) until about 6500 yr B.P. Afterward vertical growth slowed to about 0.5 mm/yr, then lateral development became dominant during the last several thousand years. The second interval is dated at 131,000 ?? 3000 yr B.P. by uranium series. This unit correlates with oxygen-isotope substage 5e and with terrace VIIa of Huon Peninsula, New Guinea, and of Main Reef-2 terrace at Atauro Island. The third interval is not dated because corals were recrystallized and it is tentatively correlated with either oxygen-isotope stages 7 or 9. The age of the fourth interval is estimated at 454,000 ?? 100,000 yr B.P. from measured 234U 238U activity ratios. This unit is correlated with either oxygen-isotope stage 9, 11, or 13. ?? 1985.

  10. In-Situ Effects of Simulated Overfishing and Eutrophication on Benthic Coral Reef Algae Growth, Succession, and Composition in the Central Red Sea.

    Directory of Open Access Journals (Sweden)

    Christian Jessen

    Full Text Available Overfishing and land-derived eutrophication are major local threats to coral reefs and may affect benthic communities, moving them from coral dominated reefs to algal dominated ones. The Central Red Sea is a highly under-investigated area, where healthy coral reefs are contending against intense coastal development. This in-situ study investigated both the independent and combined effects of manipulated inorganic nutrient enrichment (simulation of eutrophication and herbivore exclosure (simulation of overfishing on benthic algae development. Light-exposed and shaded terracotta tiles were positioned at an offshore patch reef close to Thuwal, Saudi Arabia and sampled over a period of 4 months. Findings revealed that nutrient enrichment alone affected neither algal dry mass nor algae-derived C or N production. In contrast, herbivore exclusion significantly increased algal dry mass up to 300-fold, and in conjunction with nutrient enrichment, this total increased to 500-fold. Though the increase in dry mass led to a 7 and 8-fold increase in organic C and N content, respectively, the algal C/N ratio (18±1 was significantly lowered in the combined treatment relative to controls (26±2. Furthermore, exclusion of herbivores significantly increased the relative abundance of filamentous algae on the light-exposed tiles and reduced crustose coralline algae and non-coralline red crusts on the shaded tiles. The combination of the herbivore exclusion and nutrient enrichment treatments pronounced these effects. The results of our study suggest that herbivore reduction, particularly when coupled with nutrient enrichment, favors non-calcifying, filamentous algae growth with high biomass production, which thoroughly outcompetes the encrusting (calcifying algae that dominates in undisturbed conditions. These results suggest that the healthy reefs of the Central Red Sea may experience rapid shifts in benthic community composition with ensuing effects for

  11. In-Situ Effects of Simulated Overfishing and Eutrophication on Benthic Coral Reef Algae Growth, Succession, and Composition in the Central Red Sea.

    KAUST Repository

    Jessen, Christian

    2013-06-19

    Overfishing and land-derived eutrophication are major local threats to coral reefs and may affect benthic communities, moving them from coral dominated reefs to algal dominated ones. The Central Red Sea is a highly under-investigated area, where healthy coral reefs are contending against intense coastal development. This in-situ study investigated both the independent and combined effects of manipulated inorganic nutrient enrichment (simulation of eutrophication) and herbivore exclosure (simulation of overfishing) on benthic algae development. Light-exposed and shaded terracotta tiles were positioned at an offshore patch reef close to Thuwal, Saudi Arabia and sampled over a period of 4 months. Findings revealed that nutrient enrichment alone affected neither algal dry mass nor algae-derived C or N production. In contrast, herbivore exclusion significantly increased algal dry mass up to 300-fold, and in conjunction with nutrient enrichment, this total increased to 500-fold. Though the increase in dry mass led to a 7 and 8-fold increase in organic C and N content, respectively, the algal C/N ratio (18±1) was significantly lowered in the combined treatment relative to controls (26±2). Furthermore, exclusion of herbivores significantly increased the relative abundance of filamentous algae on the light-exposed tiles and reduced crustose coralline algae and non-coralline red crusts on the shaded tiles. The combination of the herbivore exclusion and nutrient enrichment treatments pronounced these effects. The results of our study suggest that herbivore reduction, particularly when coupled with nutrient enrichment, favors non-calcifying, filamentous algae growth with high biomass production, which thoroughly outcompetes the encrusting (calcifying) algae that dominates in undisturbed conditions. These results suggest that the healthy reefs of the Central Red Sea may experience rapid shifts in benthic community composition with ensuing effects for biogeochemical cycles if

  12. In-Situ Effects of Simulated Overfishing and Eutrophication on Benthic Coral Reef Algae Growth, Succession, and Composition in the Central Red Sea.

    KAUST Repository

    Jessen, Christian; Roder, Cornelia; Lizcano, Javier; Voolstra, Christian R.; Wild, Christian

    2013-01-01

    Overfishing and land-derived eutrophication are major local threats to coral reefs and may affect benthic communities, moving them from coral dominated reefs to algal dominated ones. The Central Red Sea is a highly under-investigated area, where healthy coral reefs are contending against intense coastal development. This in-situ study investigated both the independent and combined effects of manipulated inorganic nutrient enrichment (simulation of eutrophication) and herbivore exclosure (simulation of overfishing) on benthic algae development. Light-exposed and shaded terracotta tiles were positioned at an offshore patch reef close to Thuwal, Saudi Arabia and sampled over a period of 4 months. Findings revealed that nutrient enrichment alone affected neither algal dry mass nor algae-derived C or N production. In contrast, herbivore exclusion significantly increased algal dry mass up to 300-fold, and in conjunction with nutrient enrichment, this total increased to 500-fold. Though the increase in dry mass led to a 7 and 8-fold increase in organic C and N content, respectively, the algal C/N ratio (18±1) was significantly lowered in the combined treatment relative to controls (26±2). Furthermore, exclusion of herbivores significantly increased the relative abundance of filamentous algae on the light-exposed tiles and reduced crustose coralline algae and non-coralline red crusts on the shaded tiles. The combination of the herbivore exclusion and nutrient enrichment treatments pronounced these effects. The results of our study suggest that herbivore reduction, particularly when coupled with nutrient enrichment, favors non-calcifying, filamentous algae growth with high biomass production, which thoroughly outcompetes the encrusting (calcifying) algae that dominates in undisturbed conditions. These results suggest that the healthy reefs of the Central Red Sea may experience rapid shifts in benthic community composition with ensuing effects for biogeochemical cycles if

  13. Effect of the growth temperature and the AlN mole fraction on In incorporation and properties of quaternary III-nitride layers grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Fernandez-Garrido, S.; Pereiro, J.; Munoz, E.; Calleja, E.; Redondo-Cubero, A.; Gago, R.; Bertram, F.; Christen, J.; Luna, E.; Trampert, A.

    2008-01-01

    Indium incorporation into wurtzite (0001)-oriented In x Al y Ga 1-x-y N layers grown by plasma-assisted molecular beam epitaxy was studied as a function of the growth temperature (565-635 deg. C) and the AlN mole fraction (0.01< y<0.27). The layer stoichiometry was determined by Rutherford backscattering spectrometry (RBS). RBS shows that indium incorporation decreased continuously with increasing growth temperature due to thermally enhanced dissociation of In-N bonds and for increasing AlN mole fractions. High resolution x-ray diffraction and transmission electron microscopy (TEM) measurements did not show evidence of phase separation. The mosaicity of the quaternary layers was found to be mainly determined by the growth temperature and independent on alloy composition within the range studied. However, depending on the AlN mole fraction, nanometer-sized composition fluctuations were detected by TEM. Photoluminescence spectra showed a single broad emission at room temperature, with energy and bandwidth S- and W-shaped temperature dependences typical of exciton localization by alloy inhomogeneities. Cathodoluminescence measurements demonstrated that the alloy inhomogeneities, responsible of exciton localization, occur on a lateral length scale below 150 nm, which is corroborated by TEM

  14. Decoration of ZnO Nanorods with Coral Reefs like NiO Nanostructures by the Hydrothermal Growth Method and Their Luminescence Study

    Directory of Open Access Journals (Sweden)

    Mazhar Ali Abbasi

    2014-01-01

    Full Text Available Composite nanostructures of coral reefs like p-type NiO/n-type ZnO were synthesized on fluorine-doped tin oxide glass substrates by hydrothermal growth. Structural characterization was performed by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction techniques. This investigation shows that the adopted synthesis leads to high crystalline quality nanostructures. The morphological study shows that the coral reefs like nanostructures are densely packed on the ZnO nanorods. Cathodoluminescence (CL spectra for the synthesized composite nanostructures are dominated mainly by a broad interstitial defect related luminescence centered at ~630 nm. Spatially resolved CL images reveal that the luminescence of the decorated ZnO nanostructures is enhanced by the presence of the NiO.

  15. Quaternary and Geomorphology.

    Science.gov (United States)

    Andrews, J. T.; Graf, W. L.

    1983-01-01

    Highlights conferences and meetings of organizations involved with quaternary geology and geomorphology, including International Union of Quaternary Research Conference held in Moscow. The impetus of a revision of "The Quaternary of the United States" resulted from this conference. Includes activities/aims of "Friends of the…

  16. 210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef

    Directory of Open Access Journals (Sweden)

    N. Tisnérat-Laborde

    2012-03-01

    Full Text Available Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr−1 (2.6 polyps per year. Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr−1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions. For the 80 cm-long L. pertusa colony, metal-oxide contamination remained in both the middle and basal part of the coral skeleton despite cleaning, inhibiting similar age and growth rate estimates. The youngest part of the colony was free of metal oxides and this 15 cm section had an estimated a growth rate of 8 mm yr−1, with high uncertainty (~1 polyp every two to three years. We are less certain of this 210Pb growth rate estimate which is within the lowermost

  17. Occurrence, sources and transport of antibiotics in the surface water of coral reef regions in the South China Sea: Potential risk to coral growth.

    Science.gov (United States)

    Zhang, Ruijie; Zhang, Ruiling; Yu, Kefu; Wang, Yinghui; Huang, Xueyong; Pei, Jiying; Wei, Chaoshuai; Pan, Ziliang; Qin, Zhenjun; Zhang, Gan

    2018-01-01

    Laboratory research has indicated that antibiotics had negative effects on coral growth by disturbing natural microbiota; however, no field studies have reported antibiotic contamination levels and their influence on coral growth in natural coral reef regions (CRRs). This study investigated antibiotic occurrence and sources in the surface water from CRRs that have suffered from rapid coral degradation and evaluated their risk to coral growth. These regions are in the South China Sea, including four coastal and two offshore CRRs. The results show that 13 antibiotics were detected in the coastal CRRs with concentrations ranging from 10 -2 -10 0  ng L -1 , while 5 antibiotics occurred in offshore CRRs (300-950 km from the mainland), with concentrations ranging from 10 -2 to 10 -1  ng L -1 . Their concentrations decreased gradually from the coast to offshore in the transport process. However, Yongxing Island, which is approximately 300 km from the mainland, was an exception with relatively higher concentrations than the surrounding reefs because of the ever-increasing human activity on the island. The presence of anthropogenic contaminants antibiotics in CRRs may be a potential risk to coral growth. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Reef Development on Artificial Patch Reefs in Shallow Water of Panjang Island, Central Java

    Science.gov (United States)

    Munasik; Sugiyanto; Sugianto, Denny N.; Sabdono, Agus

    2018-02-01

    Reef restoration methods are generally developed by propagation of coral fragments, coral recruits and provide substrate for coral attachment using artificial reefs (ARs). ARs have been widely applied as a tool for reef restoration in degraded natural reefs. Successful of coral restoration is determined by reef development such as increasing coral biomass, natural of coral recruits and fauna associated. Artificial Patch Reefs (APRs) is designed by combined of artificial reefs and coral transplantation and constructed by modular circular structures in shape, were deployed from small boats by scuba divers, and are suitable near natural reefs for shallow water with low visibility of Panjang Island, Central Java. Branching corals of Acropora aspera, Montipora digitata and Porites cylindrica fragments were transplanted on to each module of two units of artificial patch reefs in different periods. Coral fragments of Acropora evolved high survival and high growth, Porites fragments have moderate survival and low growth, while fragment of Montipora show in low survival and moderate growth. Within 19 to 22 months of APRs deployment, scleractinian corals were recruited on the surface of artificial patch reef substrates. The most recruits abundant was Montastrea, followed by Poritids, Pocilloporids, and Acroporids. We conclude that artificial patch reefs with developed by coral fragments and natural coral recruitment is one of an alternative rehabilitation method in shallow reef with low visibility.

  19. Artificial Reefs

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An artificial reef is a human-made underwater structure, typically built to promote marine life in areas with a generally featureless bottom, control erosion, block...

  20. Global microbialization of coral reefs.

    Science.gov (United States)

    Haas, Andreas F; Fairoz, Mohamed F M; Kelly, Linda W; Nelson, Craig E; Dinsdale, Elizabeth A; Edwards, Robert A; Giles, Steve; Hatay, Mark; Hisakawa, Nao; Knowles, Ben; Lim, Yan Wei; Maughan, Heather; Pantos, Olga; Roach, Ty N F; Sanchez, Savannah E; Silveira, Cynthia B; Sandin, Stuart; Smith, Jennifer E; Rohwer, Forest

    2016-04-25

    Microbialization refers to the observed shift in ecosystem trophic structure towards higher microbial biomass and energy use. On coral reefs, the proximal causes of microbialization are overfishing and eutrophication, both of which facilitate enhanced growth of fleshy algae, conferring a competitive advantage over calcifying corals and coralline algae. The proposed mechanism for this competitive advantage is the DDAM positive feedback loop (dissolved organic carbon (DOC), disease, algae, microorganism), where DOC released by ungrazed fleshy algae supports copiotrophic, potentially pathogenic bacterial communities, ultimately harming corals and maintaining algal competitive dominance. Using an unprecedented data set of >400 samples from 60 coral reef sites, we show that the central DDAM predictions are consistent across three ocean basins. Reef algal cover is positively correlated with lower concentrations of DOC and higher microbial abundances. On turf and fleshy macroalgal-rich reefs, higher relative abundances of copiotrophic microbial taxa were identified. These microbial communities shift their metabolic potential for carbohydrate degradation from the more energy efficient Embden-Meyerhof-Parnas pathway on coral-dominated reefs to the less efficient Entner-Doudoroff and pentose phosphate pathways on algal-dominated reefs. This 'yield-to-power' switch by microorganism directly threatens reefs via increased hypoxia and greater CO2 release from the microbial respiration of DOC.

  1. Drowned reefs and antecedent karst topography, Au'au channel, S.E. Hawaiian Islands

    Science.gov (United States)

    Grigg, R.W.; Grossman, E.E.; Earle, S.A.; Gittings, S.R.; Lott, D.; McDonough, J.

    2002-01-01

    During the last glacial maximum (LGM), about 21,000 years ago, the Hawaiian Islands of Maui, Lanai, and Molokai were interconnected by limestone bridges, creating a super-island known as Maui-Nui. Approximately 120 m of sea-level rise during the Holocene Transgression flooded, and then drowned, these bridges separating the islands by inter-island channels. A new multibeam high-resolution bathymetric survey of the channels between the islands, coupled with observations and video-transects utilizing DeepWorker-2000 submersibles, has revealed the existence of numerous drowned reef features including concentric solution basins, solution ridges (rims), sand and sediment plains, and conical-shaped reef pinnacles. The concentric basins contain flat lagoon-like bottoms that are rimmed by steep-sided limestone walls. Undercut notches rim the basins at several depths, marking either sea-level still stands or paleo-lake levels. All of the solution basins shallower than 120 m were subaerial at the LGM, and at one stage or another may have been shallow shoreline lakes. Today, about 70 drowned reef pinnacles are scattered across the Maui-Lanai underwater bridge and all are situated in wave-sheltered positions. Most drowned during the interval between 14,000 and 10,000 years ago when sea-level rise averaged 15 mm/year. Virtually all of the surficial topography in the Au'au Channel today is a product of karst processes accentuated by marginal reef growth during the Holocene. Both the submerged basins and the drowned reefs represent an archive of sea-level and climate history in Hawaii during the late Quaternary.

  2. Vaal Reefs

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Vaal Reefs Mine, the world's top gold producer with an output last quarter of 19,6 tons of gold, is to expand further with the building of an 120 000t/month run-of-mine mill at the new No 9 Shaft in the south area, linked with a carbon-in-pulp plant

  3. Comparison of growth rates estimated by otolith reading of Scorpaena porcus and Scorpaena notata caught on artificial and natural reefs of the northern Adriatic sea

    Directory of Open Access Journals (Sweden)

    Giuseppe Scarcella

    2011-01-01

    Full Text Available Despite the high number of studies on fish assemblages associated with artificial reefs and offshore platforms, little information exists on the growth rates of fish living on artificial and natural substrates. Age and growth was determined throughout otolith reading on two commercial scorpionfishes (Scorpaena porcus and Scorpaena notata caught in the surroundings of artificial structures (artificial reefs and gas platforms and natural habitats. Von Bertalanffy growth parameters were calculated for each species separately for each site. Age of S. porcus and S. notata ranged from 0 to 8 years and from 0 to 16 years, respectively. Kimura test applied to Von Bertalanffy growth curves indicated that the individuals of both species inhabiting the artificial structures had higher growth parameters than those caught in the natural habitat. The presence of artificial habitats in the northern Adriatic Sea positively affects growth rates and growth performance of both species, likely for the greater prey availability in respect to the natural open sea.Apesar do elevado número de estudos sobre as assembléias de peixes associadas a recifes artificiais e plataformas offshore, existe pouca informação sobre as taxas de crescimento dos peixes que vivem em substratos artificiais e naturais. A idade e crescimento foram determinados pela leitura de otólitos em dois peixes escorpião comerciais (Scorpaena porcus e Scorpaena notata capturados nas imediações de estruturas artificiais (recifes artificiais e plataformas de gás e habitats naturais. Parâmetros de crescimento de von Bertalanffy foram calculadoss separadamente para cada espécie e cada local. A idade de Scorpaena porcus e Scorpaena notata variou entre 0 e 8 anos e 0 e 16 anos, respectivamente. O teste Kimura aplicado às curvas de crescimento de Bertalanffy indicaram que os indivíduos das duas espécies que habitam as estruturas artificiais tinham parâmetros de crescimento mais elevados do que

  4. Algal growth and species composition under experimental control of herbivory, phosphorus and coral abundance in Glovers Reef, Belize.

    Science.gov (United States)

    McClanahan, T R; Cokos, B A; Sala, E

    2002-06-01

    The proliferation of algae on disturbed coral reefs has often been attributed to (1) a loss of large-bodied herbivorous fishes, (2) increases in sea water nutrient concentrations, particularly phosphorus, and (3) a loss of hard coral cover or a combination of these and other factors. We performed replicated small-scale caging experiments in the offshore lagoon of Glovers Reef atoll, Belize where three treatments had closed-top (no large-bodied herbivores) and one treatment had open-top cages (grazing by large-bodied herbivores). Closed-top treatments simulated a reduced-herbivory situation, excluding large fishes but including small herbivorous fishes such as damselfishes and small parrotfishes. Treatments in the closed-top cages included the addition of high phosphorus fertilizer, live branches of Acropora cervicornis and a third unmanipulated control treatment. Colonization, algal biomass and species composition on dead A. palmata "plates" were studied weekly for 50 days in each of the four treatments. Fertilization doubled the concentration of phosphorus from 0.35 to 0.77 microM. Closed-top cages, particularly the fertilizer and A. cervicornis additions, attracted more small-bodied parrotfish and damselfish than the open-top cages such that there was moderate levels of herbivory in closed-top cages. The open-top cages did, however, have a higher abundance of the chemically and morphologically defended erect algal species including Caulerpa cupressoides, Laurencia obtusa, Dictyota menstrualis and Lobophora variegata. The most herbivore-resistant calcareous green algae (i.e. Halimeda) were, however, uncommon in all treatments. Algal biomass increased and fluctuated simultaneously in all treatments over time, but algal biomass, as measured by wet, dry and decalcified weight, did not differ greatly between the treatments with only marginally higher biomass (p reefs except for creating space. In contrast, A. cervicornis appears to attract aggressive damselfish that

  5. In-Situ Effects of Simulated Overfishing and Eutrophication on Benthic Coral Reef Algae Growth, Succession, and Composition in the Central Red Sea

    OpenAIRE

    Jessen, Christian; Roder, Cornelia; Villa Lizcano, Javier Felipe; Voolstra, Christian R.; Wild, Christian

    2013-01-01

    Overfishing and land-derived eutrophication are major local threats to coral reefs and may affect benthic communities, moving them from coral dominated reefs to algal dominated ones. The Central Red Sea is a highly under-investigated area, where healthy coral reefs are contending against intense coastal development. This in-situ study investigated both the independent and combined effects of manipulated inorganic nutrient enrichment (simulation of eutrophication) and herbivore exclosure (simu...

  6. 1300 km long late Pleistocene-Holocene shelf edge barrier reef system along the western continental shelf of India: Occurrence and significance

    Digital Repository Service at National Institute of Oceanography (India)

    Vora, K.H.; Wagle, B.G.; Veerayya, M.; Almeida, F.; Karisiddaiah, S.M.

    . It is surmised that coral/algal reef growth commenced with the advent of the Holocene trangression and favorable antecedent topography, and continued until early Holocene. Subsequently, rapid sea level rise drowned the reefs. The shelf edge reefs, therefore...

  7. Second Quaternary dating workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  8. Second Quaternary dating workshop

    International Nuclear Information System (INIS)

    1999-01-01

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  9. Holocene coral patch reef ecology and sedimentary architecture, Northern Belize, Central America

    Energy Technology Data Exchange (ETDEWEB)

    Mazzullo, S.J.; Anderson-Underwood, K.E.; Burke, C.D.; Bischoff, W.D. (Wichita State Univ., KS (United States))

    1992-12-01

    Coral patch reefs are major components of Holocene platform carbonate facies systems in tropical and subtropical areas. The biotic composition, growth and relationship to sea level history, and diagenetic attributes of a representative Holocene patch reef ([open quotes]Elmer Reef[close quotes]) in the Mexico Rocks complex in northern Belize are described and compared to those of Holocene patch reefs in southern Belize. Elmer Reef has accumulated in shallow (2.5 m) water over the last 420 yr, under static sea level conditions. Rate of vertical construction is 0.3-0.5 m/100 yr, comparable to that of patch reefs in southern Belize. A pronounced coral zonation exists across Elmer Reef, with Monastrea annularis dominating on its crest and Acropora cervicornis occurring on its windward and leeward flanks. The dominance of Montastrea on Elmer Reef is unlike that of patch reefs in southern Belize, in which this coral assumes only a subordinate role in reef growth relative to that of Acropora palmata. Elmer Reef locally is extensively biodegraded and marine, fibrous aragonite and some bladed high-magnesium calcite cements occur throughout the reef section, partially occluding corallites and interparticle pores in associated sands. Patch reefs in southern Belize have developed as catch-up and keep-up reefs in a transgressive setting. In contrast, the dominant mode of growth of Elmer Reef, and perhaps other patch reefs in Mexico Rocks, appears to be one of lateral rather than vertical accretion. This style of growth occurs in a static sea level setting where there is only limited accommodation space because of the shallowness of the water, and such reefs are referred to as [open quotes]expansion reefs[close quotes]. 39 refs., 8 figs., 2 tabs.

  10. Coral reefs - Specialized ecosystems

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.

    This paper discusses briefly some aspects that characterize and differentiate coral reef ecosystems from other tropical marine ecosystems. A brief account on the resources that are extractable from coral reefs, their susceptibility to natural...

  11. NMFS Reef Survey Forms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Reef Environmental Survey Project (REEF) mission to educate and enlist divers in the conservation of marine habitats is accomplished primarily through its Fish...

  12. High Latitude Reefs: A Potential Refuge for Reef Builders

    Science.gov (United States)

    Amat, A.; Bates, N.

    2003-04-01

    Coral reefs globally show variable signs of deterioration or community structure changes due to a host of anthropogenic and natural factors. In these global scenarios, rates of calcification by reef builders such as Scleractinian corals are predicted to significantly decline in the future due to the increase in atmospheric CO_2. When considering the response of reefs to the present climate change, temperature effects should also be taken into account. Here, we investigate the simultaneous impact of temperature and CO_2 on the high-latitude Bermuda coral reef system (32^oN, 64^oE)through a series of in vitro experiments at different CO_2 levels and seasonally different summer (27^oC) and winter (20^oC) temperature conditions. Four species of Scleractinian corals (Porites astreoides, Diploria labyrinthiformis, Madracis mirabilis and decactis) were acclimated for three months at: 20^oC and 27^oC (both with CO_2 levels at 400 ppm (control) and 700 ppm). Growth was assessed by buoyant weight techniques during the acclimation period. Photosynthesis, respiration and calcification were measured at the end of this period using respirometric chambers. A reproduction experiment was also undertaken under 27^oC. Photosynthesis mainly remains constant or increases under high CO_2 conditions. The results of the integrated calcification measurements confirm the hypothesis that an increase in CO_2 induces a decrease in calcification. However an increase in photosynthesis can be observed when CO_2 is unfavorable for calcification suggesting that a biological control of calcification through photosynthesis could prevent a drop in the calcification potential. Buoyant weight results indicate that the CO_2 impact could be less detrimental under lower temperature. This result will be compared with the instantaneous calcification measurements in the chambers and some in situ coral growth assessments in winter and summer conditions. The consequences for the response of marginal reefs

  13. Linking Wave Forcing to Coral Cover and Structural Complexity Across Coral Reef Flats

    Science.gov (United States)

    Harris, D. L.; Rovere, A.; Parravicini, V.; Casella, E.

    2015-12-01

    The hydrodynamic regime is a significant component in the geomorphic and ecological development of coral reefs. The energy gradients and flow conditions generated by the breaking and transformation of waves across coral reef crests and flats drive changes in geomorphic structure, and coral growth form and distribution. One of the key aspects in regulating the wave energy propagating across reef flats is the rugosity or roughness of the benthic substrate. Rugosity and structural complexity of coral reefs is also a key indicator of species diversity, ecological functioning, and reef health. However, the links between reef rugosity, coral species distribution and abundance, and hydrodynamic forcing are poorly understood. In this study we examine this relationship by using high resolution measurement of waves in the surf zone and coral reef benthic structure.Pressure transducers (logging at 4 Hz) were deployed in cross reef transects at two sites (Tiahura and Ha'apiti reef systems) in Moorea, French Polynesia with wave characteristics determined on a wave by wave basis. A one dimensional hydrodynamic model (XBeach) was calibrated from this data to determine wave processes on the reef flats under average conditions. Transects of the reef benthic structure were conducted using photographic analysis and the three dimensional reef surface was constructed using structure from motion procedures. From this analysis reef rugosity, changes in coral genus and growth form, and across reef shifts in benthic community were determined. The results show clear changes in benthic assemblages along wave energy gradients with some indication of threshold values of wave induced bed shear stress above which live coral cover was reduced. Reef rugosity was shown to be significantly along the cross-reef transect which has important implications for accurate assessment of wave dissipation across coral reef flats. Links between reef rugosity and coral genus were also observed and may indicate

  14. Watershed processes from ridge to reef: consequences of feral ungulates for coral reef and effects of watershed management

    Science.gov (United States)

    Gordon Tribble; Jonathan Stock; Jim Jacobi

    2016-01-01

    Molokai’s south shore has some of Hawaii’s most extensive and best-developed coral reefs. Historic terrigenous sedimentation appears to have impacted coral growth along several miles of fringing reef. The land upslope of the reef consists of small watersheds with streams that flow intermittently to the ocean. A USGS gage at the outlet of one of the most impacted...

  15. Mine waste disposal leads to lower coral cover, reduced species richness and a predominance of simple coral growth forms on a fringing coral reef in Papua New Guinea.

    Science.gov (United States)

    Haywood, M D E; Dennis, D; Thomson, D P; Pillans, R D

    2016-04-01

    A large gold mine has been operating at the Lihir Island Group, Papua New Guinea since 1997. The mine disposes of waste rock in nearshore waters, impacting nearby coral communities. During 2010, 2012 we conducted photographic surveys at 73 sites within 40 km of the mine to document impacts of mining operations on the hard coral communities. Coral communities close to the mine (∼2 km to the north and south of the mine) were depaurperate, but surprisingly, coral cover and community composition beyond this range appeared to be relatively similar, suggesting that the mine impacts were limited spatially. In particular, we found mining operations have resulted in a significant decrease in coral cover (4.4% 1.48 km from the disposal site c.f. 66.9% 10.36 km from the disposal site), decreased species richness and a predominance of less complex growth forms within ∼2 km to the north and south of the mine waste disposal site. In contrast to the two 'snapshot' surveys of corals performed in 2010 and 2012, long term data (1999-2012) based on visual estimates of coral cover suggested that impacts on coral communities may have been more extensive than this. With global pressures on the world's coral reefs increasing, it is vital that local, direct anthropogenic pressures are reduced, in order to help offset the impacts of climate change, disease and predation. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  16. The last interglacial period at Guantanamo Bay, Cuba and an estimate of late Quaternary tectonic uplift rate in a strike-slip regime

    Science.gov (United States)

    Schweig, E. S.; Muhs, D. R.; Simmons, K. R.; Halley, R. B.

    2015-12-01

    Guantanamo Bay, Cuba is an area dominated by a strike-slip tectonic regime and is therefore expected to have very low Quaternary uplift rates. We tested this hypothesis by study of an unusually well preserved emergent reef terrace around the bay. Up to 12 m of unaltered, growth-position reef corals are exposed at about 40 sections examined around ˜40 km of coastline. Maximum reef elevations in the protected, inner part of the bay are ˜11-12 m, whereas outer-coast shoreline angles of wave-cut benches are as high as ˜14 m. Fifty uranium-series analyses of unrecrystallized corals from six localities yield ages ranging from ˜134 ka to ˜115 ka, when adjusted for small biases due to slightly elevated initial 234U/238U values. Thus, ages of corals correlate this reef to the peak of the last interglacial period, marine isotope stage (MIS) 5.5. Previously, we dated the Key Largo Limestone to the same high-sea stand in the tectonically stable Florida Keys. Estimates of paleo-sea level during MIS 5.5 in the Florida Keys are ~6.6 to 8.3 m above present. Assuming a similar paleo-sea level in Cuba, this yields a long-term tectonic uplift rate of 0.04-0.06 m/ka over the past ~120 ka. This estimate supports the hypothesis that the tectonic uplift rate should be low in this strike-slip regime. Nevertheless, on the southeast coast of Cuba, east of our study area, we have observed flights of multiple marine terraces, suggesting either (1) a higher uplift rate or (2) an unusually well-preserved record of pre-MIS 5.5 terraces not observed at Guantanamo Bay.

  17. Coral Reef Remote Sensing: Helping Managers Protect Reefs in a Changing Climate

    Science.gov (United States)

    Eakin, C.; Liu, G.; Li, J.; Muller-Karger, F. E.; Heron, S. F.; Gledhill, D. K.; Christensen, T.; Rauenzahn, J.; Morgan, J.; Parker, B. A.; Skirving, W. J.; Nim, C.; Burgess, T.; Strong, A. E.

    2010-12-01

    Climate change and ocean acidification are already having severe impacts on coral reef ecosystems. Warming oceans have caused corals to bleach, or expel their symbiotic algae (zooxanthellae) with alarming frequency and severity and have contributed to a rise in coral infectious diseases. Ocean acidification is reducing the availability of carbonate ions needed by corals and many other marine organisms to build structural components like skeletons and shells and may already be slowing the coral growth. These two impacts are already killing corals and slowing reef growth, reducing biodiversity and the structure needed to provide crucial ecosystem services. NOAA’s Coral Reef Watch (CRW) uses a combination of satellite data, in situ observations, and models to provide coral reef managers, scientists, and others with information needed to monitor threats to coral reefs. The advance notice provided by remote sensing and models allows resource managers to protect corals, coral reefs, and the services they provide, although managers often encounter barriers to implementation of adaptation strategies. This talk will focus on application of NOAA’s satellite and model-based tools that monitor the risk of mass coral bleaching on a global scale, ocean acidification in the Caribbean, and coral disease outbreaks in selected regions, as well as CRW work to train managers in their use, and barriers to taking action to adapt to climate change. As both anthropogenic CO2 and temperatures will continue to rise, local actions to protect reefs are becoming even more important.

  18. Influence of Quaternary Benzophenantridine and Protopine Alkaloids on Growth Performance, Dietary Energy, Carcass Traits, Visceral Mass, and Rumen Health in Finishing Ewes under Conditions of Severe Temperature-humidity Index

    Directory of Open Access Journals (Sweden)

    A. Estrada-Angulo

    2016-05-01

    Full Text Available Twenty Pelibuey×Katahdin ewes (35±2.3 kg were used to determine the effects of the consumption of standardized plant extract containing a mixture of quaternary benzophenanthridine alkaloids and protopine alkaloids (QBA+PA on growth performance, dietary energetics, visceral mass, and ruminal epithelial health in heat-stressed ewes fed with a high-energy corn-based diet. The basal diet (13.9% crude protein and 2.09 Mcal of net energy [NE] of maintenance/kg of dry matter contained 49.7% starch and 15.3% neutral detergent fiber. Source of QBA+PA was Sangrovit RS (SANG which contains 3 g of quaternary benzophenathridine and protopine alkaloids per kg of product. Treatments consisted of a daily consumption of 0 or 0.5 g SANG/ewe. Ewes were grouped by weight and assigned to 10 pens (5 pens/treatment, with two ewes per pen. The experimental period lasted 70 days. The mean temperature humidity index during the course of this experiment was 81.7±1.0 (severe heat stress. There were no treatment effects on water intake. Dry matter intake was not affected (p = 0.70 by treatments, but the group fed SANG had a numerically (11.2% higher gain in comparison to the control group, SANG improved gain efficiency (8.3%, p = 0.04, dietary NE (5.2%, p<0.01 and the observed-to-expected NE (5.9%, p<0.01. Supplemental SANG did not affect (p≥0.12 carcass characteristics, chemical composition of shoulder, and organ weights (g/kg empty body weight of stomach complex, intestines, and heart/lung. Supplemental SANG decreased liver weight (10.3%, p = 0.02 and increased visceral fat (16.9%, p = 0.02. Rumen epithelium of ewes fed SANG had lower scores for cellular dropsical degeneration (2.08 vs 2.34, p = 0.02, parakeratosis (1.30 vs 1.82, p = 0.03 and neutrophil infiltration (2.08 vs 2.86, p = 0.05 than controls. It is concluded that SANG supplementation helped ameliorate the negative effects of severe heat on growth performance of feedlot ewes fed high-energy corn

  19. The wicked problem of China's disappearing coral reefs.

    Science.gov (United States)

    Hughes, Terry P; Huang, Hui; Young, Matthew A L

    2013-04-01

    We examined the development of coral reef science and the policies, institutions, and governance frameworks for management of coral reefs in China in order to highlight the wicked problem of preserving reefs while simultaneously promoting human development and nation building. China and other sovereign states in the region are experiencing unprecedented economic expansion, rapid population growth, mass migration, widespread coastal development, and loss of habitat. We analyzed a large, fragmented literature on the condition of coral reefs in China and the disputed territories of the South China Sea. We found that coral abundance has declined by at least 80% over the past 30 years on coastal fringing reefs along the Chinese mainland and adjoining Hainan Island. On offshore atolls and archipelagos claimed by 6 countries in the South China Sea, coral cover has declined from an average of >60% to around 20% within the past 10-15 years. Climate change has affected these reefs far less than coastal development, pollution, overfishing, and destructive fishing practices. Ironically, these widespread declines in the condition of reefs are unfolding as China's research and reef-management capacity are rapidly expanding. Before the loss of corals becomes irreversible, governance of China's coastal reefs could be improved by increasing public awareness of declining ecosystem services, by providing financial support for training of reef scientists and managers, by improving monitoring of coral reef dynamics and condition to better inform policy development, and by enforcing existing regulations that could protect coral reefs. In the South China Sea, changes in policy and legal frameworks, refinement of governance structures, and cooperation among neighboring countries are urgently needed to develop cooperative management of contested offshore reefs. © 2012 Society for Conservation Biology.

  20. Quaternary dating methods

    International Nuclear Information System (INIS)

    Mahaney, W.C.

    1984-01-01

    The papers in this book cover absolute, relative and multiple dating methods, and have been written by specialists from a number of different earth sciences disciplines - their common interest being the dating of geological materials within the Quaternary. Papers on absolute dating methods discuss radiocarbon, uranium-series, potassium argon, 40 Ar/ 39 Ar, paleomagnetic, obsidian hydration, thermoluminescence, amino acid racemization, tree rings, and lichenometric techniques. Those on relative dating include discussions on various geomorphic relative age indicators such as drainage density changes, hypsometric integrals, bifurcation ratios, stream junction angles, spur morphology, hillslope geometry, and till sheet characteristics. The papers on multiple dating cite examples from the Rocky Mountains, Australia, Lake Agassiz Basin, and the Southern Andes. Also included is the panel discussion which reviews and assesses the information presented, and a field trip guide which discusses the sequences of Wisconian tills and interlayered lacustrine and fluvial sediments. (orig.)

  1. Will Coral Islands maintain their growth over the next century? A deterministic model of sediment availability at Lady Elliot Island, Great Barrier Reef.

    Directory of Open Access Journals (Sweden)

    Sarah Hamylton

    Full Text Available A geomorphic assessment of reef system calcification is conducted for past (3200 Ka to present, present and future (2010-2100 time periods. Reef platform sediment production is estimated at 569 m3 yr-1 using rate laws that express gross community carbonate production as a function of seawater aragonite saturation, community composition and rugosity and incorporating estimates of carbonate removal from the reef system. Key carbonate producers including hard coral, crustose coralline algae and Halimeda are mapped accurately (mean R2 = 0.81. Community net production estimates correspond closely to independent census-based estimates made in-situ (R2 = 0.86. Reef-scale outputs are compared with historic rates of production generated from (i radiocarbon evidence of island deposition initiation around 3200 years ago, and (ii island volume calculated from a high resolution island digital elevation model. Contemporary carbonate production rates appear to be remarkably similar to historical values of 573 m3 yr-1. Anticipated future seawater chemistry parameters associated with an RCP8.5 emissions scenario are employed to model rates of net community calcification for the period 2000-2100 on the basis of an inorganic aragonite precipitation law, under the assumption of constant benthic community character. Simulations indicate that carbonate production will decrease linearly to a level of 118 m3 yr-1 by 2100 and that by 2150 aragonite saturation levels may no longer support the positive budgetary status necessary to sustain island accretion. Novel aspects of this assessment include the development of rate law parameters to realistically represent the variable composition of coral reef benthic carbonate producers, incorporation of three dimensional rugosity of the entire reef platform and the coupling of model outputs with both historical radiocarbon dating evidence and forward hydrochemical projections to conduct an assessment of island evolution

  2. Will Coral Islands maintain their growth over the next century? A deterministic model of sediment availability at Lady Elliot Island, Great Barrier Reef.

    Science.gov (United States)

    Hamylton, Sarah

    2014-01-01

    A geomorphic assessment of reef system calcification is conducted for past (3200 Ka to present), present and future (2010-2100) time periods. Reef platform sediment production is estimated at 569 m3 yr-1 using rate laws that express gross community carbonate production as a function of seawater aragonite saturation, community composition and rugosity and incorporating estimates of carbonate removal from the reef system. Key carbonate producers including hard coral, crustose coralline algae and Halimeda are mapped accurately (mean R2 = 0.81). Community net production estimates correspond closely to independent census-based estimates made in-situ (R2 = 0.86). Reef-scale outputs are compared with historic rates of production generated from (i) radiocarbon evidence of island deposition initiation around 3200 years ago, and (ii) island volume calculated from a high resolution island digital elevation model. Contemporary carbonate production rates appear to be remarkably similar to historical values of 573 m3 yr-1. Anticipated future seawater chemistry parameters associated with an RCP8.5 emissions scenario are employed to model rates of net community calcification for the period 2000-2100 on the basis of an inorganic aragonite precipitation law, under the assumption of constant benthic community character. Simulations indicate that carbonate production will decrease linearly to a level of 118 m3 yr-1 by 2100 and that by 2150 aragonite saturation levels may no longer support the positive budgetary status necessary to sustain island accretion. Novel aspects of this assessment include the development of rate law parameters to realistically represent the variable composition of coral reef benthic carbonate producers, incorporation of three dimensional rugosity of the entire reef platform and the coupling of model outputs with both historical radiocarbon dating evidence and forward hydrochemical projections to conduct an assessment of island evolution through time

  3. Satellite imaging coral reef resilience at regional scale. A case-study from Saudi Arabia.

    Science.gov (United States)

    Rowlands, Gwilym; Purkis, Sam; Riegl, Bernhard; Metsamaa, Liisa; Bruckner, Andrew; Renaud, Philip

    2012-06-01

    We propose a framework for spatially estimating a proxy for coral reef resilience using remote sensing. Data spanning large areas of coral reef habitat were obtained using the commercial QuickBird satellite, and freely available imagery (NASA, Google Earth). Principles of coral reef ecology, field observation, and remote observations, were combined to devise mapped indices. These capture important and accessible components of coral reef resilience. Indices are divided between factors known to stress corals, and factors incorporating properties of the reef landscape that resist stress or promote coral growth. The first-basis for a remote sensed resilience index (RSRI), an estimate of expected reef resilience, is proposed. Developed for the Red Sea, the framework of our analysis is flexible and with minimal adaptation, could be extended to other reef regions. We aim to stimulate discussion as to use of remote sensing to do more than simply deliver habitat maps of coral reefs. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Quantifying climatological ranges and anomalies for Pacific coral reef ecosystems.

    Science.gov (United States)

    Gove, Jamison M; Williams, Gareth J; McManus, Margaret A; Heron, Scott F; Sandin, Stuart A; Vetter, Oliver J; Foley, David G

    2013-01-01

    Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic-biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will help

  5. Quantifying Climatological Ranges and Anomalies for Pacific Coral Reef Ecosystems

    Science.gov (United States)

    Gove, Jamison M.; Williams, Gareth J.; McManus, Margaret A.; Heron, Scott F.; Sandin, Stuart A.; Vetter, Oliver J.; Foley, David G.

    2013-01-01

    Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic–biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will

  6. Quantifying climatological ranges and anomalies for Pacific coral reef ecosystems.

    Directory of Open Access Journals (Sweden)

    Jamison M Gove

    Full Text Available Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic-biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km from 85% of our study locations

  7. Pliocene-Quaternary history of Futuna island, south Vanuatu, southwest Pacific

    International Nuclear Information System (INIS)

    Neef, G.; McCulloch, M.T.

    2001-01-01

    Uranium-series ages from thermal ionisation mass spectrometry are reported here for the raised coral reefs of Futuna Island, which lies adjacent to the eastern margin of the backarc Futuna Trough in south Vanuatu, southwest Pacific. U-series ages from coral from the lowest raised reef indicate that its upper part is most likely to be ca 210 ka, whereas the most elevated raised reef has a likely age of ca 520 ka (range 600-440 ka). The inferred Pliocene-Quaternary history for Futuna Island and the adjacent Futuna Trough is: (i) formation of the Pliocene - Early Quaternary basaltic-andesite cone in a southeast part of the Vanuatu Island Arc; (ii) inception of the Futuna Trough (adjacent to the west margin of Futuna Island) since 1.8Ma; (iii) subsequent uplift of the volcanic cone above sea-level caused ∼ 500 m of its upper part to be removed by marine erosion; (iv) the island then subsided and at least 160 m of limestone was deposited on the truncated cone; and (v) during the period 520 ka to ca 210 ka seven fringing reefs formed at the margin of the cone as the island was uplifted. Since ca 210 ka Futuna further subsided and, as a result, the post ca 210 ka history of the island is obscure. Copyright (2001) Geological Society of Australia

  8. Quaternary structure of methemoglobin

    International Nuclear Information System (INIS)

    Chevion, M.; Ilan, Y.A.; Samuni, A.; Navok, T.; Czapski, G.

    1979-01-01

    The pulse radiolysis of solutions of adult human methemoglobin was used to reduce a single heme iron within the protein tetramers. The valence hybrids thus formed were reacted with oxygen. Kinetics of the reactions were studied. The effects of pH and inositol hexaphosphate were examined. The kinetics of the ligation of oxygen to stripped valence hybrids showed a single phase behavior at the pH range 6.5 to 9. As the pH was lowered below 6.5, a second, slower phase became apparent. In the presence of inositol hexaphosphate, above pH 8, the kinetics of oxygen binding was of a single phase. As the pH was lowered, a transition to a second, slower phase was noticed. Below pH 7, the slower phase was the only detectable one. On this basis, it is concluded that human adult stripped methemoglobin resides in an R quarternary structure, while the presence of IHP stabilizes the T structure at pH below 7.5. This transition between the quaternary structures of methemoglobin cannot be accounted for by the switch between the high spin and the low spin states of the ferric iron. This switch of spin state takes place at pH>8.2

  9. Coral Ecosystem Resilience, Conservation and Management on the Reefs of Jamaica in the Face of Anthropogenic Activities and Climate Change

    Directory of Open Access Journals (Sweden)

    M. James C. Crabbe

    2010-06-01

    Full Text Available Knowledge of factors that are important in reef resilience and integrity help us understand how reef ecosystems react following major anthropogenic and environmental disturbances. The North Jamaican fringing reefs have shown some recent resilience to acute disturbances from hurricanes and bleaching, in addition to the recurring chronic stressors of over-fishing and land development. Factors that can improve coral reef resilience are reviewed, and reef rugosity is shown to correlate with coral cover and growth, particularly for branching Acropora species. The biodiversity index for the Jamaican reefs was lowered after the 2005 mass bleaching event, as were the numbers of coral colonies, but both had recovered by 2009. The importance of coastal zone reef management strategies and the economic value of reefs are discussed, and a protocol is suggested for future management of Jamaican reefs.

  10. Artificial reefs and reef restoration in the Laurentian Great Lakes

    Science.gov (United States)

    McLean, Matthew W.; Roseman, Edward; Pritt, Jeremy J.; Kennedy, Gregory W.; Manny, Bruce A.

    2015-01-01

    We reviewed the published literature to provide an inventory of Laurentian Great Lakes artificial reef projects and their purposes. We also sought to characterize physical and biological monitoring for artificial reef projects in the Great Lakes and determine the success of artificial reefs in meeting project objectives. We found records of 6 artificial reefs in Lake Erie, 8 in Lake Michigan, 3 in Lakes Huron and Ontario, and 2 in Lake Superior. We found 9 reefs in Great Lakes connecting channels and 6 reefs in Great Lakes tributaries. Objectives of artificial reef creation have included reducing impacts of currents and waves, providing safe harbors, improving sport-fishing opportunities, and enhancing/restoring fish spawning habitats. Most reefs in the lakes themselves were incidental (not created purposely for fish habitat) or built to improve local sport fishing, whereas reefs in tributaries and connecting channels were more frequently built to benefit fish spawning. Levels of assessment of reef performance varied; but long-term monitoring was uncommon as was assessment of physical attributes. Artificial reefs were often successful at attracting recreational species and spawning fish; however, population-level benefits of artificial reefs are unclear. Stressors such as sedimentation and bio-fouling can limit the effectiveness of artificial reefs as spawning enhancement tools. Our investigation underscores the need to develop standard protocols for monitoring the biological and physical attributes of artificial structures. Further, long-term monitoring is needed to assess the benefits of artificial reefs to fish populations and inform future artificial reef projects.

  11. Temperatures and Melt Water Contents at the Onset of Phenocryst Growth in Quaternary Nepheline-Normative Basalts Erupted along the Tepic-Zacoalco Rift in Western Mexico

    Science.gov (United States)

    Mesa, J.; Lange, R. A.; Pu, X.

    2017-12-01

    Nepheline-normative, high-Mg basalts erupted from the western Mexican arc, along the Tepic-Zacoalco rift (TZR), have a trace-element signature consistent with an asthenosphere source, whereas calc-alkaline basalts erupted from the central Mexican arc in the Michoacan-Guanajuato volcanic field (MGVF) have a trace-element signature consistent with a mantle source strongly affected by subduction fluids. In this study, olivine-melt thermometry and plagioclase-liquid hygrometry are used to constrain the temperature and melt water content of the alkaline TZR basalts. The presence of diffusion-limited growth textures in olivine and plagioclase phenocrysts provide preliminary evidence of rapid growth during ascent. For each basalt sample, a histogram of all analyzed olivines in each sample allows the most Fo-rich composition to be identified, which matches the calculated composition at the liquidus via MELTS (Ghiorso & Sack, 1995; Asimow & Ghiorso, 1998) at fO2 values of QFM +2. Therefore a newly developed olivine-melt thermometer, based on DNiol/liq (Pu et al., 2017) was used to calculate temperature at the onset of olivine crystallization during ascent. Temperatures range from 1076-1247°C, whereas those calculated using an olivine-melt thermometer based on DMgol/liq range from 1141-1236 °C. Olivine-melt thermometers based on DMgol/liq are sensitive to melt H2O content, therefore ΔT = TMg - TNi (≤ 82 degrees) may be used as a qualitative indicator of melt H2O (≤ 2.6 wt% H2O; Pu et al., 2017). When temperatures from the Ni-thermometer are applied to the most calcic plagioclase in each sample (Waters & Lange, 2015), calculated melt H2O contents range from 1.3-1.9 (± 0.4) wt%. These values are significantly lower than those obtained from high-Mg calc-alkaline basalts from the MGVF using similar methods (1.9-5.0 wt%; Pu et al., 2017), consistent with a reduced involvement of slab-derived fluids in the origin of the alkaline TZR basalts from western Mexico.

  12. Quaternary Ammonium Polyethyleneimine: Antibacterial Activity Ira

    International Nuclear Information System (INIS)

    Farber, Y.; Domb, A.G.; Golenser, J.; Beyth, N.; Weiss, E.I.

    2010-01-01

    Quaternary ammonium polyethyleneimine- (QA-PEI-) based nanoparticles were synthesized using two synthetic methods, reductive amination and N-alkylation. According to the first method, QA-PEI nanoparticles were synthesized by cross-linking with glutaraldehyde followed by reductive amination with octanal and further N-methylation with methyl iodide. The second method is based on crosslinking with dialkyl halide followed by N-alkylation with octyl halide and further N-methylation with methyl iodide. QA-PEI nanoparticles completely inhibited bacterial growth (>106 bacteria), including both Gram-positive, that is, Staphylococcus aureus at 80 μ/mL, and Gram-negative, that is, Escherichia coli at 320 μ/mL. Activity analysis revealed that the degree of alkylation and N-methylation of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl alkylated QA-PEI alkylated at 1 : 1 mole ratio (primary amine of PEI monomer units/alkylating agent). Also, cytotoxicity studies on MAT-LyLu and MBT cell lines were performed with QA-PEI nanoparticles. These findings confirm previous reports that poly cations bearing quaternary ammonium moieties inhibit bacterial growth in vitro and have a potential use as additives in medical devices which need antibacterial properties.

  13. High refuge availability on coral reefs increases the vulnerability of reef-associated predators to overexploitation.

    Science.gov (United States)

    Rogers, Alice; Blanchard, Julia L; Newman, Steven P; Dryden, Charlie S; Mumby, Peter J

    2018-02-01

    Refuge availability and fishing alter predator-prey interactions on coral reefs, but our understanding of how they interact to drive food web dynamics, community structure and vulnerability of different trophic groups is unclear. Here, we apply a size-based ecosystem model of coral reefs, parameterized with empirical measures of structural complexity, to predict fish biomass, productivity and community structure in reef ecosystems under a broad range of refuge availability and fishing regimes. In unfished ecosystems, the expected positive correlation between reef structural complexity and biomass emerges, but a non-linear effect of predation refuges is observed for the productivity of predatory fish. Reefs with intermediate complexity have the highest predator productivity, but when refuge availability is high and prey are less available, predator growth rates decrease, with significant implications for fisheries. Specifically, as fishing intensity increases, predators in habitats with high refuge availability exhibit vulnerability to over-exploitation, resulting in communities dominated by herbivores. Our study reveals mechanisms for threshold dynamics in predators living in complex habitats and elucidates how predators can be food-limited when most of their prey are able to hide. We also highlight the importance of nutrient recycling via the detrital pathway, to support high predator biomasses on coral reefs. © 2018 by the Ecological Society of America.

  14. Coral reefs and eutrophication

    International Nuclear Information System (INIS)

    Stambler, N.

    1999-01-01

    Coral reefs are found in oligotrophic waters, which are poor in nutrients such as nitrogen, phosphate, and possibly iron. In spite of this, coral reefs exhibit high gross primary productivity rates. They thrive in oligotrophic conditions because of the symbiotic relationship between corals and dinoflagellate algae (zooxanthellae) embedded in the coral tissue. In their mutualistic symbiosis, the zooxanthellae contribute their photosynthetic capability as the basis for the metabolic energy of the whole association, and eventually of a great part of the entire reef ecosystem

  15. Growth effect on liver fatty acid composition of damselfishes genus Abudefduf collected in coral reef habitats of the Malaysian South China Sea.

    Science.gov (United States)

    Arai, Takaomi; Amalina, Razikin; Bachok, Zainudin

    2015-01-01

    In order to understand feeding ecology, habitat use and migration of coral reef fish, fatty acid composition was examined in damselfish species Abudefduf bengalensis and A. sexfasciatus collected in the Malaysian South China Sea. Proportions of saturated fatty acids (SAFA) ranged from 49.5% to 74.2%, with the highest proportions in fatty acids, the second highest was monounsaturated fatty acids (MUFA) ranged from 21.4% to 47.4% and the proportion of polyunsaturated fatty acids (PUFA) was the lowest ranged from 3.1% to 6.0%. Palmitic acid (16:0) was the most common in SAFA, oleic acid (C18:1ω9c) was the dominant in MUFA and linolenic acid (C18:3n3) showed the highest proportion in PUFA. Fatty acid concentrations, especially in SAFA and MUFA, could be related to physiological condition, sexual development, and recent feeding events. The diet shift revealed by the fatty acid composition suggests changes in habitat use and migration scale in coral reef environment of genus Abudefduf.

  16. Coral Reef Guidance

    Science.gov (United States)

    Guidance prepared by EPA and Army Corps of Engineers concerning coral reef protection under the Clean Water Act, Marine Protection, Research, and Sanctuaries Act, Rivers and Harbors Act, and Federal Project Authorities.

  17. Modern stromatolite reefs fringing a brackish coastline, Chetumal Bay, Belize

    Science.gov (United States)

    Rasmussen, Kenneth A.; MacIntyre, Ian G.; Prufert, Leslie

    1993-03-01

    Reef-forming stromatolites have been discovered along the windward shoreline of Chetumal Bay, Belize, just south of the mouth of the Rio Hondo. The reefs and surrounding sediment are formed by the precipitation of submicrocrystalline calcite upon the sheaths of filamentous cyanobacteria, principally Scytonema, under a seasonally fluctuating, generally brackish salinity regime (0‰10‰). Well-cemented, wave-resistant buttresses of coalesced stromatolite heads form arcuate or club-shaped reefs up to 42 m long and 1.5 m in relief that are partially emergent during low tide. Oncolitic rubble fields are present between well-developed reefs along the 1.5 km trend, which parallels the mangrove coastline 40-100 m offshore. The mode of reef growth, as illustrated by surface relief and internal structure, changes with increasing water depth and energy, proximity to bottom sediments, and dominant cyanobacterial taxa. Sediment trapping and binding by cyanobacteria are of limited importance to reef growth, and occur only where stromatolite heads or oncolites are in direct contact with the sandy sea floor. Radiocarbon-dated mangrove peat at the base of the reef suggests that it began to form about 2300 yr B.P., as shoreline encrustations that were stranded offshore following storm-induced retreat of the mangrove coast.

  18. Global warming and coral reefs. Chikyu ondanka to sangosho

    Energy Technology Data Exchange (ETDEWEB)

    Kayane, H [Geological Survey of Japan, Tokyo (Japan)

    1991-09-01

    A summary is described with respect to the relation of the global warming with coral reefs on the environmental estimation based on the sea level rise, and the development of counter-technologies utilizing the CO{sub 2} fixing capability of coral reefs. if no measures are taken to reduce discharge of greenhouse effective gases, the air temperature will rise by 1{degree}C by the year 2025, and 3{degree}C by 2100. The thermal expansion of sea water and partial melting of land ice caused from the said temperature rise will cause the annual sea level rising speed to climb to 6 mm in the next century. It is estimated that the sea level will be elevated higher by 25 cm by the year 2025, 65 cm by 2100, and the maximum of 1 m than the present level. The upward growth rate of reef ridges is between 1m and 4m in 1000 years, and the growth of reef rides as the frameworks of coral reefs and lime alga ridges can not catch up the sea level rise of 6 mm/year. This may cause a possibility of sea water erosion or inundation. As a possible contermeasure, an expectation is placed on structuring coral reef eco-factories which may be possible as a result of elucidating the CO{sub 2} fixing mechanism in coral reefs and utilizing the capability to its maximum. 23 refs., 7 figs., 1 tab.

  19. Holocene emerged coral reef in Takarajima and Kodakarajima, Ryukyu islands, Southwest Japan

    International Nuclear Information System (INIS)

    Nakata, Takashi; Omoto, Kunio; Koba, Motoharu

    1978-01-01

    Due to the recent development of radiometric dating, coral reefs emerged in Holocene epoch are studied intensively worldwidely in relation to sea level change and coral reef formation. Attempt was made to determine the age, pattern and growth rate of coral reefs in the marginal area of coral sea in the Northwest Pacific. Field observation was made in the emerged coral reefs in Takarajima and Kodakarajima islands and the samples for radiocarbon dating were taken from geological sections across the emerged reefs. These islands are located at about 29 deg 10 min N, 129 deg 15 min E, where warm Kuroshio current pushes the margin of coral sea northward, and furnished with flourishing development of coral reefs emerged in both pleistocence and Holocene epochs. Though without earthquake records, it is assumed that Holocene reefs have been terraced due to sudden uplift associated with major earthquakes. (Mori, K.)

  20. Holocene emerged coral reef in Takarajima and Kodakarajima, Ryukyu islands, Southwest Japan

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, T; Omoto, K; Koba, M [Tohoku Univ., Sendai (Japan). Faculty of Science

    1978-06-01

    Due to the recent development of radiometric dating, coral reefs emerged in Holocene epoch are studied intensively worldwidely in relation to sea level change and coral reef formation. Attempt was made to determine the age, pattern and growth rate of coral reefs in the marginal area of coral sea in the Northwest Pacific. Field observation was made in the emerged coral reefs in Takarajima and Kodakarajima islands and the samples for radiocarbon dating were taken from geological sections across the emerged reefs. These islands are located at about 29 deg 10 min N, 129 deg 15 min E, where warm Kuroshio current pushes the margin of coral sea northward, and furnished with flourishing development of coral reefs emerged in both pleistocence and Holocene epochs. Though without earthquake records, it is assumed that Holocene reefs have been terraced due to sudden uplift associated with major earthquakes.

  1. Coral reefs in the Anthropocene.

    Science.gov (United States)

    Hughes, Terry P; Barnes, Michele L; Bellwood, David R; Cinner, Joshua E; Cumming, Graeme S; Jackson, Jeremy B C; Kleypas, Joanie; van de Leemput, Ingrid A; Lough, Janice M; Morrison, Tiffany H; Palumbi, Stephen R; van Nes, Egbert H; Scheffer, Marten

    2017-05-31

    Coral reefs support immense biodiversity and provide important ecosystem services to many millions of people. Yet reefs are degrading rapidly in response to numerous anthropogenic drivers. In the coming centuries, reefs will run the gauntlet of climate change, and rising temperatures will transform them into new configurations, unlike anything observed previously by humans. Returning reefs to past configurations is no longer an option. Instead, the global challenge is to steer reefs through the Anthropocene era in a way that maintains their biological functions. Successful navigation of this transition will require radical changes in the science, management and governance of coral reefs.

  2. The structure and composition of Holocene coral reefs in the Middle Florida Keys

    Science.gov (United States)

    Toth, Lauren T.; Stathakopoulos, Anastasios; Kuffner, Ilsa B.

    2016-07-21

    The Florida Keys reef tract (FKRT) is the largest coral-reef ecosystem in the continental United States. The modern FKRT extends for 362 kilometers along the coast of South Florida from Dry Tortugas National Park in the southwest, through the Florida Keys National Marine Sanctuary (FKNMS), to Fowey Rocks reef in Biscayne National Park in the northeast. Most reefs along the FKRT are sheltered by the exposed islands of the Florida Keys; however, large channels are located between the islands of the Middle Keys. These openings allow for tidal transport of water from Florida Bay onto reefs in the area. The characteristics of the water masses coming from Florida Bay, which can experience broad swings in temperature, salinity, nutrients, and turbidity over short periods of time, are generally unfavorable or “inimical” to coral growth and reef development.Although reef habitats are ubiquitous throughout most of the Upper and Lower Keys, relatively few modern reefs exist in the Middle Keys most likely because of the impacts of inimical waters from Florida Bay. The reefs that are present in the Middle Keys generally are poorly developed compared with reefs elsewhere in the region. For example, Acropora palmata has been the dominant coral on shallow-water reefs in the Caribbean over the last 1.5 million years until populations of the coral declined throughout the region in recent decades. Although A. palmata was historically abundant in the Florida Keys, it was conspicuously absent from reefs in the Middle Keys. Instead, contemporary reefs in the Middle Keys have been dominated by occasional massive (that is, boulder or head) corals and, more often, small, non-reef-building corals.Holocene reef cores have been collected from many locations along the FKRT; however, despite the potential importance of the history of reefs in the Middle Florida Keys to our understanding of the environmental controls on reef development throughout the FKRT, there are currently no published

  3. Feedbacks Between Wave Energy And Declining Coral Reef Structure: Implications For Coastal Morphodynamics

    Science.gov (United States)

    Grady, A. E.; Jenkins, C. J.; Moore, L. J.; Potts, D. C.; Burgess, P. M.; Storlazzi, C. D.; Elias, E.; Reidenbach, M. A.

    2013-12-01

    The incident wave energy dissipated by the structural complexity and bottom roughness of coral reef ecosystems, and the carbonate sediment produced by framework-building corals, provide natural shoreline protection and nourishment, respectively. Globally, coral reef ecosystems are in decline as a result of ocean warming and acidification, which is exacerbated by chronic regional stressors such as pollution and disease. As a consequence of declining reef health, many reef ecosystems are experiencing reduced coral cover and shifts to dominance by macroalgae, resulting in a loss of rugosity and thus hydrodynamic roughness. As coral reef architecture is compromised and carbonate skeletons are eroded, wave energy dissipation and sediment transport patterns--along with the carbonate sediment budget of the coastal environment--may be altered. Using a Delft3D numerical model of the south-central Molokai, Hawaii, fringing reef, we simulate the effects of changing reef states on wave energy and sediment transport. To determine the temporally-varying effects of biotic and abiotic stressors such as storms and bleaching on the reef structure and carbonate production, we couple Delft3D with CarboLOT, a model that simulates growth and competition of carbonate-producing organisms. CarboLOT is driven by the Lotka-Volterra population ecology equations and niche suitability principles, and accesses the CarboKB database for region-specific, carbonate-producing species information on growth rates, reproduction patterns, habitat suitability, as well as organism geometries. Simulations assess how changing reef states--which alter carbonate sediment production and reef morphology and thus hydrodynamic roughness--impact wave attenuation and sediment transport gradients along reef-fronted beaches. Initial results suggest that along fringing reefs having characteristics similar to the Molokai fringing reef, projected sea level rise will likely outpace coral reef accretion, and the increased

  4. NOAA Coral Reef Watch Larval Connectivity, Florida Reef Tract

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Climate change threatens even the best-protected and most remote reefs. Reef recovery following catastrophic disturbance usually requires disturbed sites be reseeded...

  5. Coastal nutrification and coral health at Porto Seguro reefs, Brazil

    Science.gov (United States)

    Costa, O.; Attrill, M.; Nimmo, M.

    2003-04-01

    correlation between zoanthids and algal abundance and a positive correlation with the amount of available space for settlement. On the offshore reef, correlation of algal cover with both zoanthids and available space were negative, suggesting that hard substrate may be the primary limiting factor for algal settlement and growth in the nearshore reefs. Highly variable physical disturbances (like wave energy and low tide exposure) between landward and seaward reef sides appear to be the factors controlling algal distribution in the offshore reef. Highly spatial variability in coral cover ultimately reflects the patchy distribution of stony corals over the reefs.

  6. Reef Visual Census (RVC) data.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Provide data on frequency of occurrence , density abundance, and length frequency of reef fish throughout Florida reef tract from 1978 forward.

  7. DIVERSITY OF REEF FISH FUNGSIONAL GROUPS IN TERMS OF CORAL REEF RESILIENCES

    Directory of Open Access Journals (Sweden)

    Isa Nagib edrus

    2017-01-01

    Full Text Available Infrastructure development in the particular sites of  Seribu Islands as well as those in main land of Jakarta City increased with coastal population this phenomenon is likely to increase the effects to the adjacent coral waters of Seribu Islands.  Chemical pollutants, sedimentation, and domestic wastes are the common impact and threatening, the survival of coral reef ecosystem. Coral reef resiliences naturaly remained on their processes under many influences of supporting factors. One of the major factor is the role of reef fish functional groups on controling algae growth to recolonize coral juveniles. The  aim of this study to obtain data of a herbivory and other fish functional groups of reef fishes in the Pari Islands that are resilience indicators, or that may indicate the effectiveness of management actions. A conventional scientific approach on fish diversity and abundance data gathering was conducted by the underwater visual cencus. Diversity values of the reef fish functional groups, such as the abundance of individual fish including species, were collected and tabulated by classes and weighted as a baseline to understand the resilience of coral reed based on Obura and Grimsditch (2009 techniques. The results succesfully identified several fish functional groups such as harbivores (21 species, carnivores (13 species and fish indicator (5 species occurred in the area. Regarding the aspects of fish density and its diversity, especially herbivorous fish functional group, were presumably in the state of rarely available to support the coral reef resiliences. Resilience indices ranged from 1 (low level to 3 (moderate level and averages of the quality levels ranged from 227 to 674. These levels were inadequate to support coral reef recolonization.

  8. Positive Feedbacks Enhance Macroalgal Resilience on Degraded Coral Reefs.

    Science.gov (United States)

    Dell, Claire L A; Longo, Guilherme O; Hay, Mark E

    2016-01-01

    Many reefs have shifted from coral and fish dominated habitats to less productive macroalgal dominated habitats, and current research is investigating means of reversing this phase shift. In the tropical Pacific, overfished reefs with inadequate herbivory can become dominated by the brown alga Sargassum polycystum. This alga suppresses recruitment and survival of corals and fishes, thus limiting the potential for reef recovery. Here we investigate the mechanisms that reinforce S. polycystum dominance and show that in addition to negatively affecting other species, this species acts in a self-reinforcing manner, positively promoting survival and growth of conspecifics. We found that survival and growth of both recruit-sized and mature S. polycystum fronds were higher within Sargassum beds than outside the beds and these results were found in both protected and fished reefs. Much of this benefit resulted from reduced herbivory within the Sargassum beds, but adult fronds also grew ~50% more within the beds even when herbivory did not appear to be occurring, suggesting some physiological advantage despite the intraspecific crowding. Thus via positive feedbacks, S. polycystum enhances its own growth and resistance to herbivores, facilitating its dominance (perhaps also expansion) and thus its resilience on degraded reefs. This may be a key feedback mechanism suppressing the recovery of coral communities in reefs dominated by macroalgal beds.

  9. Positive Feedbacks Enhance Macroalgal Resilience on Degraded Coral Reefs.

    Directory of Open Access Journals (Sweden)

    Claire L A Dell

    Full Text Available Many reefs have shifted from coral and fish dominated habitats to less productive macroalgal dominated habitats, and current research is investigating means of reversing this phase shift. In the tropical Pacific, overfished reefs with inadequate herbivory can become dominated by the brown alga Sargassum polycystum. This alga suppresses recruitment and survival of corals and fishes, thus limiting the potential for reef recovery. Here we investigate the mechanisms that reinforce S. polycystum dominance and show that in addition to negatively affecting other species, this species acts in a self-reinforcing manner, positively promoting survival and growth of conspecifics. We found that survival and growth of both recruit-sized and mature S. polycystum fronds were higher within Sargassum beds than outside the beds and these results were found in both protected and fished reefs. Much of this benefit resulted from reduced herbivory within the Sargassum beds, but adult fronds also grew ~50% more within the beds even when herbivory did not appear to be occurring, suggesting some physiological advantage despite the intraspecific crowding. Thus via positive feedbacks, S. polycystum enhances its own growth and resistance to herbivores, facilitating its dominance (perhaps also expansion and thus its resilience on degraded reefs. This may be a key feedback mechanism suppressing the recovery of coral communities in reefs dominated by macroalgal beds.

  10. Synergistic impacts of global warming on the resilience of coral reefs

    OpenAIRE

    Bozec, Yves-Marie; Mumby, Peter J.

    2015-01-01

    Recent epizootics have removed important functional species from Caribbean coral reefs and left communities vulnerable to alternative attractors. Global warming will impact reefs further through two mechanisms. A chronic mechanism reduces coral calcification, which can result in depressed somatic growth. An acute mechanism, coral bleaching, causes extreme mortality when sea temperatures become anomalously high. We ask how these two mechanisms interact in driving future reef state (coral cover...

  11. The diversity of coral reefs: what are we missing?

    Directory of Open Access Journals (Sweden)

    Laetitia Plaisance

    Full Text Available Tropical reefs shelter one quarter to one third of all marine species but one third of the coral species that construct reefs are now at risk of extinction. Because traditional methods for assessing reef diversity are extremely time consuming, taxonomic expertise for many groups is lacking, and marine organisms are thought to be less vulnerable to extinction, most discussions of reef conservation focus on maintenance of ecosystem services rather than biodiversity loss. In this study involving the three major oceans with reef growth, we provide new biodiversity estimates based on quantitative sampling and DNA barcoding. We focus on crustaceans, which are the second most diverse group of marine metazoans. We show exceptionally high numbers of crustacean species associated with coral reefs relative to sampling effort (525 species from a combined, globally distributed sample area of 6.3 m(2. The high prevalence of rare species (38% encountered only once, the low level of spatial overlap (81% found in only one locality and the biogeographic patterns of diversity detected (Indo-West Pacific>Central Pacific>Caribbean are consistent with results from traditional survey methods, making this approach a reliable and efficient method for assessing and monitoring biodiversity. The finding of such large numbers of species in a small total area suggests that coral reef diversity is seriously under-detected using traditional survey methods, and by implication, underestimated.

  12. Coral Reef Coverage Percentage on Binor Paiton-Probolinggo Seashore

    Directory of Open Access Journals (Sweden)

    Dwi Budi Wiyanto

    2016-01-01

    Full Text Available The coral reef damage in Probolinggo region was expected to be caused by several factors. The first one comes from its society that exploits fishery by using cyanide toxin and bomb. The second one goes to the extraction of coral reef, which is used as decoration or construction materials. The other factor is likely caused by the existence of large industry on the seashore, such as Electric Steam Power Plant (PLTU Paiton and others alike. Related to the development of coral reef ecosystem, availability of an accurate data is crucially needed to support the manner of future policy, so the research of coral reef coverage percentage needs to be conducted continuously. The aim of this research is to collect biological data of coral reef and to identify coral reef coverage percentage in the effort of constructing coral reef condition basic data on Binor, Paiton, and Probolinggo regency seashore. The method used in this research is Line Intercept Transect (LIT method. LIT method is a method that used to decide benthic community on coral reef based on percentage growth, and to take note of benthic quantity along transect line. Percentage of living coral coverage in 3 meters depth on this Binor Paiton seashore that may be categorized in a good condition is 57,65%. While the rest are dead coral that is only 1,45%, other life form in 23,2%, and non-life form in 17,7%. A good condition of coral reef is caused by coral reef transplantation on the seashore, so this coral reef is dominated by Acropora Branching. On the other hand, Mortality Index (IM of coral reef resulted in 24,5%. The result from observation and calculation of coral reef is dominated by Hard Coral in Acropora Branching (ACB with coral reef coverage percentage of 39%, Coral Massive (CM with coral reef coverage percentage of 2,85%, Coral Foliose (CF with coral reef coverage percentage of 1,6%, and Coral Mushroom (CRM with coral reef coverage percentage of 8,5%. Observation in 10 meters depth

  13. Coral Reef Coverage Percentage on Binor Paiton-Probolinggo Seashore

    Directory of Open Access Journals (Sweden)

    Dwi Budi Wiyanto

    2016-02-01

    Full Text Available The coral reef damage in Probolinggo region was expected to be caused by several factors. The first one comes from its society that exploits fishery by using cyanide toxin and bomb. The second one goes to the extraction of coral reef, which is used as decoration or construction materials. The other factor is likely caused by the existence of large industry on the seashore, such as Electric Steam Power Plant (PLTU Paiton and others alike. Related to the development of coral reef ecosystem, availability of an accurate data is crucially needed to support the manner of future policy, so the research of coral reef coverage percentage needs to be conducted continuously. The aim of this research is to collect biological data of coral reef and to identify coral reef coverage percentage in the effort of constructing coral reef condition basic data on Binor, Paiton, and Probolinggo regency seashore. The method used in this research is Line Intercept Transect (LIT method. LIT method is a method that used to decide benthic community on coral reef based on percentage growth, and to take note of benthic quantity along transect line. Percentage of living coral coverage in 3 meters depth on this Binor Paiton seashore that may be categorized in a good condition is 57,65%. While the rest are dead coral that is only 1,45%, other life form in 23,2%, and non-life form in 17,7%. A good condition of coral reef is caused by coral reef transplantation on the seashore, so this coral reef is dominated by Acropora Branching. On the other hand, Mortality Index (IM of coral reef resulted in 24,5%. The result from observation and calculation of coral reef is dominated by Hard Coral in Acropora Branching (ACB with coral reef coverage percentage of 39%, Coral Massive (CM with coral reef coverage percentage of 2,85%, Coral Foliose (CF with coral reef coverage percentage of 1,6%, and Coral Mushroom (CRM with coral reef coverage percentage of 8,5%. Observation in 10 meters depth

  14. Coral reef ecosystem

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Wafar, S.

    ), on submerged banks like Gave shani bank (13°24'N; 73°45'E) (Nair and Qasim 1978) andSidere~ko Bank (13°43.5' N; 73°42'E) (Rao 1972) and as stray individual units off Visakhapatnam (Bakus, G. personal communication) and Pondicherry (Ramesh, A. personal... communication). Fossil reefs, drowned as a result of the Holocene sea level rise, occur at 92, 85, 75 and 55 m depth along .. ~ !! ":2 0. ~ Figure 3.1 Graphical Representation of the SO-Box Model of a Caribbean Coral Reef Key: 1. Benthic producers. 2. Detritus...

  15. Are coral reefs victims of their own past success?

    Science.gov (United States)

    Renema, Willem; Pandolfi, John M; Kiessling, Wolfgang; Bosellini, Francesca R; Klaus, James S; Korpanty, Chelsea; Rosen, Brian R; Santodomingo, Nadiezhda; Wallace, Carden C; Webster, Jody M; Johnson, Kenneth G

    2016-04-01

    As one of the most prolific and widespread reef builders, the staghorn coral Acropora holds a disproportionately large role in how coral reefs will respond to accelerating anthropogenic change. We show that although Acropora has a diverse history extended over the past 50 million years, it was not a dominant reef builder until the onset of high-amplitude glacioeustatic sea-level fluctuations 1.8 million years ago. High growth rates and propagation by fragmentation have favored staghorn corals since this time. In contrast, staghorn corals are among the most vulnerable corals to anthropogenic stressors, with marked global loss of abundance worldwide. The continued decline in staghorn coral abundance and the mounting challenges from both local stress and climate change will limit the coral reefs' ability to provide ecosystem services.

  16. Modern coral reefs of western Atlantic: new geological perspective

    Energy Technology Data Exchange (ETDEWEB)

    MacIntyre, I.G.

    1988-11-01

    Contrary to popular belief of the late 1960s, western Atlantic Holocene reefs have a long history and are not feeble novice nearshore veneers that barely survived postglacial temperatures. Rather, the growth of these reefs kept pace with the rising seas of the Holocene transgression and their development was, for the most part, controlled by offshore wave-energy conditions and the relationship between changing sea levels and local shelf topography. Thus, the outer shelves of the eastern Caribbean in areas of high energy have relict reefs consisting predominantly of Acropora palmata, a robust shallow-water coral. The flooding of adjacent shelves during the postglacial transgression introduced stress conditions that terminated the growth of these reefs. When, about 7000 yr ago, shelf-water conditions improved, scattered deeper water coral communities reestablished themselves on these stranded shelf-edge reefs, and fringing and bank-barrier reefs began to flourish in shallow coastal areas. At the same time, the fragile and rapidly growing Acropora cervicornis and other corals flourished at greater depths on the more protected shelves of the western Caribbean and the Gulf of Mexico. As a result, late Holocene buildups more than 30 m thick developed in those areas. 7 figures.

  17. Biorock Electric Reefs Grow Back Severely Eroded Beaches in Months

    Directory of Open Access Journals (Sweden)

    Thomas J. F. Goreau

    2017-10-01

    Full Text Available Severely eroded beaches on low lying islands in Indonesia were grown back in a few months—believed to be a record—using an innovative method of shore protection, Biorock electric reef technology. Biorock shore protection reefs are growing limestone structures that get stronger with age and repair themselves, are cheaper than concrete or rock sea walls and breakwaters, and are much more effective at shore protection and beach growth. Biorock reefs are permeable, porous, growing, self-repairing structures of any size or shape, which dissipate wave energy by internal refraction, diffraction, and frictional dissipation. They do not cause reflection of waves like hard sea walls and breakwaters, which erodes the sand in front of, and then underneath, such structures, until they collapse. Biorock reefs stimulate settlement, growth, survival, and resistance to the environmental stress of all forms of marine life, restoring coral reefs, sea grasses, biological sand production, and fisheries habitat. Biorock reefs can grow back eroded beaches and islands faster than the rate of sea level rise, and are the most cost-effective method of shore protection and adaptation to global sea level rise for low lying islands and coasts.

  18. Age accuracy and resolution of Quaternary corals used as proxies for sea level

    Science.gov (United States)

    Edinger, E. N.; Burr, G. S.; Pandolfi, J. M.; Ortiz, J. C.

    2007-01-01

    The accuracy of global eustatic sea level curves measured from raised Quaternary reefs, using radiometric ages of corals at known heights, may be limited by time-averaging, which affects the variation in coral age at a given height. Time-averaging was assessed in uplifted Holocene reef sequences from the Huon Peninsula, Papua New Guinea, using radiocarbon dating of coral skeletons in both horizontal transects and vertical sequences. Calibrated 2σ age ranges varied from 800 to 1060 years along horizontal transects, but weighted mean ages calculated from 15-18 dates per horizon were accurate to a resolution within 154-214 yr. Approximately 40% of the variability in age estimate resulted from internal variability inherent to 14C estimates, and 60% was due to time-averaging. The accuracy of age estimates of sea level change in studies using single dated corals as proxies for sea level is probably within 1000 yr of actual age, but can be resolved to ≤ 250 yr if supported by dates from analysis of a statistical population of corals at each stratigraphic interval. The range of time-averaging among reef corals was much less than that for shelly benthos. Ecological time-averaging dominated over sedimentological time averaging for reef corals, opposite to patterns reported from shelly benthos in siliciclastic environments.

  19. Designing Novel Quaternary Quantum Reversible Subtractor Circuits

    Science.gov (United States)

    Haghparast, Majid; Monfared, Asma Taheri

    2018-01-01

    Reversible logic synthesis is an important area of current research because of its ability to reduce energy dissipation. In recent years, multiple valued logic has received great attention due to its ability to reduce the width of the reversible circuit which is a main requirement in quantum technology. Subtractor circuits are between major components used in quantum computers. In this paper, we will discuss the design of a quaternary quantum reversible half subtractor circuit using quaternary 1-qudit, 2-qudit Muthukrishnan-Stroud and 3-qudit controlled gates and a 2-qudit Generalized quaternary gate. Then a design of a quaternary quantum reversible full subtractor circuit based on the quaternary half subtractor will be presenting. The designs shall then be evaluated in terms of quantum cost, constant input, garbage output, and hardware complexity. The proposed quaternary quantum reversible circuits are the first attempt in the designing of the aforementioned subtractor.

  20. Patch-reef morphology as a proxy for Holocene sea-level variability, Northern Florida Keys, USA

    Science.gov (United States)

    Brock, J.C.; Palaseanu-Lovejoy, M.; Wright, C.W.; Nayegandhi, A.

    2008-01-01

    A portion of the northern Florida Keys reef tract was mapped with the NASA Experimental Advanced Airborne Research Lidar (EAARL) and the morphology of patch reefs was related to variations in Holocene sea level. Following creation of a lidar digital elevation model (DEM), geospatial analyses delineated morphologic attributes of 1,034 patch reefs (reef depth, basal area, height, volume, and topographic complexity). Morphometric analysis revealed two morphologically different populations of patch reefs associated with two distinct depth intervals above and below a water depth of 7.7 m. Compared to shallow reefs, the deep reefs were smaller in area and volume and showed no trend in topographic complexity relative to water depth. Shallow reefs were more variable in area and volume and became flatter and less topographically complex with decreasing water depth. The knoll-like morphology of deep reefs was interpreted as consistent with steady and relatively rapidly rising early Holocene sea level that restricted the lateral growth of reefs. The morphology of shallow 'pancake-shaped' reefs at the highest platform elevations was interpreted as consistent with fluctuating sea level during the late Holocene. Although the ultimate cause for the morphometric depth trends remains open to interpretation, these interpretations are compatible with a recent eustatic sea-level curve that hindcasts fluctuating late Holocene sea level. Thus it is suggested that the morphologic differences represent two stages of reef accretion that occurred during different sea-level conditions. ?? 2008 Springer-Verlag.

  1. Quaternary palaeoceanography and palaeogeography in Northern Denmark

    DEFF Research Database (Denmark)

    Knudsen, Karen Luise; Conradsen, Keld; Heier‐Nielsen, Susanne

    1996-01-01

    Palaeoenvironmental reconstructions from the Skagen record contribute to the understanding of Late Quaternary climatic changes and variations in the oceanographic circulation pattern in the entire North Atlantic region. The Skagen cores penetrated c. 192 m of Quaternary sediments comprising two...... the Holocene, including the Pleistocene-Holocene transition. Results from the study of lithology, foraminifera, stable isotope measurements and radiocarbon dates are reviewed while emphasizing the most important contributions to the general understanding of the North Atlantic Quaternary history....

  2. Coral Reef Biological Criteria

    Science.gov (United States)

    Coral reefs worldwide are experiencing decline from a variety of stressors. Some important stressors are land-based sources of pollution and human activities in the coastal zone. However, few tools are available to offset the impact of these stressors. The Clean Water Act (CWA...

  3. Mapping Mesophotic Reefs Along the Brazilian Continental Margin

    Science.gov (United States)

    Bastos, A.; Moura, R.; Amado Filho, G.; Ferreira, L.; Boni, G.; Vedoato, F.; D'Agostini, D.; Lavagnino, A. C.; Leite, M. D.; Quaresma, V.

    2017-12-01

    Submerged or drowned reefs constitute an important geological record of sea level variations, forming the substrate for the colonization of modern benthic mesophotic communities. Although mapping mesophotic reefs has increased in the last years, their spatial distribution is poorly known and the worldwide occurrence of this reef habitat maybe underestimated. The importance in recognizing the distribution of mesophotic reefs is that they can act as a refuge for corals during unsuitable environmental conditions and a repository for shallow water corals. Here we present the result of several acoustic surveys that mapped and discovered new mesophotic reefs along the Eastern and Equatorial Brazilian Continental Margin. Seabed mapping was carried out using multibeam and side scan sonars. Ground truthing was obtained using drop camera or scuba diving. Mesophotic reefs were mapped in water depths varying from 30 to 100m and under distinct oceanographic conditions, especially in terms of river load input and shelf width. Reefs showed distinct morphologies, from low relief banks and paleovalleys to shelf edge ridges. Extensive occurrence of low relief banks were mapped along the most important coralline complex province in the South Atlantic, the Abrolhos Shelf. These 30 to 40m deep banks, have no more than 3 meters in height and may represent fringing reefs formed during sea level stabilization. Paleovalleys mapped along the eastern margin showed the occurrence of coralgal ledges along the channel margins. Paleovalleys are usually deeper than 45m and are associated with outer shelf rhodolith beds. Shelf edge ridges (80 to 120m deep) were mapped along both margins and are related to red algal encrusting irregular surfaces that have more than 3m in height, forming a rigid substrate for coral growth. Along the Equatorial Margin, off the Amazon mouth, shelf edge patch reefs and rhodolith beds forming encrusting surfaces and shelf edge ridges were mapped in water depths greater

  4. Bermuda's balancing act: The economic dependence of cruise and air tourism on healthy coral reefs

    NARCIS (Netherlands)

    van Beukering, P.J.H.; Sarkis, S.; van der Putten, L.; Papyrakis, E.

    2015-01-01

    Although Bermuda has to date managed to achieve equilibrium between tourism and coral reef conservation, this delicate balance may be threatened by the growth and changing face of the tourism industry. This may result in negative impacts on the coral reefs and services provided by this valuable

  5. Recent advances in quaternary geochronology

    International Nuclear Information System (INIS)

    Poupeau, G.

    1983-01-01

    Significant progress has occurred in quaternary geochronology. These include both (i) improvements in Fission Track and Thermoluminescence dating, as well as (ii) new technologies for short-lived (i.e. with half lives 6 yrs) radionuclide measurements as with the 14 C or uranium series desequilibrium dating, and finally (iii) the emergence of entirely new dating approches as the Electron Spin Resonnance Method. The aim of this paper is to review these progresses and the new areas they open geochronology for the past-miocene times. (author) [pt

  6. Coral health on reefs near mining sites in New Caledonia.

    Science.gov (United States)

    Heintz, T; Haapkylä, J; Gilbert, A

    2015-07-23

    Coral health data are poorly documented in New Caledonia, particularly from reefs chronically subject to anthropogenic and natural runoff. We investigated patterns of coral disease and non-disease conditions on reefs situated downstream of mining sites off the coast of New Caledonia. Surveys were conducted in March 2013 at 2 locations along the west coast and 2 locations along the east coast of the main island. Only 2 coral diseases were detected: growth anomalies and white syndrome. The most prevalent signs of compromised health at each location were sediment damage and algal overgrowth. These results support earlier findings that sedimentation and turbidity are major threats to in-shore reefs in New Caledonia. The Poritidae-dominated west coast locations were more subject to sediment damage, algal overgrowth and growth anomalies compared to the Acroporidae-dominated east coast locations. If growth form and resistance of coral hosts influence these results, differences in environmental conditions including hydro-dynamism between locations may also contribute to these outputs. Our results highlight the importance of combining coral health surveys with measurements of coral cover when assessing the health status of a reef, as reefs with high coral cover may have a high prevalence of corals demonstrating signs of compromised health.

  7. Microbial and sponge loops modify fish production in phase-shifting coral reefs.

    Science.gov (United States)

    Silveira, Cynthia B; Silva-Lima, Arthur W; Francini-Filho, Ronaldo B; Marques, Jomar S M; Almeida, Marcelo G; Thompson, Cristiane C; Rezende, Carlos E; Paranhos, Rodolfo; Moura, Rodrigo L; Salomon, Paulo S; Thompson, Fabiano L

    2015-10-01

    Shifts from coral to algae dominance of corals reefs have been correlated to fish biomass loss and increased microbial metabolism. Here we investigated reef benthic and planktonic primary production, benthic dissolved organic carbon (DOC) release and bacterial growth efficiency in the Abrolhos Bank, South Atlantic. Benthic DOC release rates are higher while water column bacterial growth efficiency is lower at impacted reefs. A trophic model based on the benthic and planktonic primary production was able to predict the observed relative fish biomass in healthy reefs. In contrast, in impacted reefs, the observed omnivorous fish biomass is higher, while that of the herbivorous/coralivorous fish is lower than predicted by the primary production-based model. Incorporating recycling of benthic-derived carbon in the model through microbial and sponge loops explains the difference and predicts the relative fish biomass in both reef types. Increased benthic carbon release rates and bacterial carbon metabolism, but decreased bacterial growth efficiency could lead to carbon losses through respiration and account for the uncoupling of benthic and fish production in phase-shifting reefs. Carbon recycling by microbial and sponge loops seems to promote an increase of small-bodied fish productivity in phase-shifting coral reefs. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Abrolhos bank reef health evaluated by means of water quality, microbial diversity, benthic cover, and fish biomass data.

    Directory of Open Access Journals (Sweden)

    Thiago Bruce

    Full Text Available The health of the coral reefs of the Abrolhos Bank (Southwestern Atlantic was characterized with a holistic approach using measurements of four ecosystem components: (i inorganic and organic nutrient concentrations, [1] fish biomass, [1] macroalgal and coral cover and (iv microbial community composition and abundance. The possible benefits of protection from fishing were particularly evaluated by comparing sites with varying levels of protection. Two reefs within the well-enforced no-take area of the National Marine Park of Abrolhos (Parcel dos Abrolhos and California were compared with two unprotected coastal reefs (Sebastião Gomes and Pedra de Leste and one legally protected but poorly enforced coastal reef (the "paper park" of Timbebas Reef. The fish biomass was lower and the fleshy macroalgal cover was higher in the unprotected reefs compared with the protected areas. The unprotected and protected reefs had similar seawater chemistry. Lower vibrio CFU counts were observed in the fully protected area of California Reef. Metagenome analysis showed that the unprotected reefs had a higher abundance of archaeal and viral sequences and more bacterial pathogens, while the protected reefs had a higher abundance of genes related to photosynthesis. Similar to other reef systems in the world, there was evidence that reductions in the biomass of herbivorous fishes and the consequent increase in macroalgal cover in the Abrolhos Bank may be affecting microbial diversity and abundance. Through the integration of different types of ecological data, the present study showed that protection from fishing may lead to greater reef health. The data presented herein suggest that protected coral reefs have higher microbial diversity, with the most degraded reef (Sebastião Gomes showing a marked reduction in microbial species richness. It is concluded that ecological conditions in unprotected reefs may promote the growth and rapid evolution of opportunistic

  9. Coral Reefs: Beyond Mortality?

    Directory of Open Access Journals (Sweden)

    Charles Sheppard

    2000-01-01

    Full Text Available The scale of the collapse of coral reef communities in 1998 following a warming episode (Wilkinson, 2000 was unprecedented, and took many people by surprise. The Indian Ocean was the worst affected with a coral mortality over 75% in many areas such as the Chagos Archipelago (Sheppard, 1999, Seychelles (Spencer et al., 2000 and Maldives (McClanahan, 2000. Several other locations were affected at least as much, with mortality reaching 100% (to the nearest whole number; this is being compiled by various authors (e.g., CORDIO, in press. For example, in the Arabian Gulf, coral mortality is almost total across many large areas of shallow water (Sheppard, unpublished; D. George and D. John, personal communication. The mortality is patchy of course, depending on currents, location inside or outside lagoons, etc., but it is now possible to swim for over 200 m and see not one remaining living coral or soft coral on some previously rich reefs.

  10. Digital reef rugosity estimates coral reef habitat complexity.

    Science.gov (United States)

    Dustan, Phillip; Doherty, Orla; Pardede, Shinta

    2013-01-01

    Ecological habitats with greater structural complexity contain more species due to increased niche diversity. This is especially apparent on coral reefs where individual coral colonies aggregate to give a reef its morphology, species zonation, and three dimensionality. Structural complexity is classically measured with a reef rugosity index, which is the ratio of a straight line transect to the distance a flexible chain of equal length travels when draped over the reef substrate; yet, other techniques from visual categories to remote sensing have been used to characterize structural complexity at scales from microhabitats to reefscapes. Reef-scale methods either lack quantitative precision or are too time consuming to be routinely practical, while remotely sensed indices are mismatched to the finer scale morphology of coral colonies and reef habitats. In this communication a new digital technique, Digital Reef Rugosity (DRR) is described which utilizes a self-contained water level gauge enabling a diver to quickly and accurately characterize rugosity with non-invasive millimeter scale measurements of coral reef surface height at decimeter intervals along meter scale transects. The precise measurements require very little post-processing and are easily imported into a spreadsheet for statistical analyses and modeling. To assess its applicability we investigated the relationship between DRR and fish community structure at four coral reef sites on Menjangan Island off the northwest corner of Bali, Indonesia and one on mainland Bali to the west of Menjangan Island; our findings show a positive relationship between DRR and fish diversity. Since structural complexity drives key ecological processes on coral reefs, we consider that DRR may become a useful quantitative community-level descriptor to characterize reef complexity.

  11. Determining the extent and characterizing coral reef habitats of the northern latitudes of the Florida Reef Tract (Martin County).

    Science.gov (United States)

    Walker, Brian K; Gilliam, David S

    2013-01-01

    Climate change has recently been implicated in poleward shifts of many tropical species including corals; thus attention focused on higher-latitude coral communities is warranted to investigate possible range expansions and ecosystem shifts due to global warming. As the northern extension of the Florida Reef Tract (FRT), the third-largest barrier reef ecosystem in the world, southeast Florida (25-27° N latitude) is a prime region to study such effects. Most of the shallow-water FRT benthic habitats have been mapped, however minimal data and limited knowledge exist about the coral reef communities of its northernmost reaches off Martin County. First benthic habitat mapping was conducted using newly acquired high resolution LIDAR bathymetry and aerial photography where possible to map the spatial extent of coral reef habitats. Quantitative data were collected to characterize benthic cover and stony coral demographics and a comprehensive accuracy assessment was performed. The data were then analyzed in a habitat biogeography context to determine if a new coral reef ecosystem region designation was warranted. Of the 374 km(2) seafloor mapped, 95.2% was Sand, 4.1% was Coral Reef and Colonized Pavement, and 0.7% was Other Delineations. Map accuracy assessment yielded an overall accuracy of 94.9% once adjusted for known map marginal proportions. Cluster analysis of cross-shelf habitat type and widths indicated that the benthic habitats were different than those further south and warranted designation of a new coral reef ecosystem region. Unlike the FRT further south, coral communities were dominated by cold-water tolerant species and LIDAR morphology indicated no evidence of historic reef growth during warmer climates. Present-day hydrographic conditions may be inhibiting poleward expansion of coral communities along Florida. This study provides new information on the benthic community composition of the northern FRT, serving as a baseline for future community shift and

  12. Holocene reef accretion: southwest Molokai, Hawaii, U.S.A.

    Science.gov (United States)

    Engels, Mary S.; Fletcher, Charles H.; Field, Michael E.; Storlazzi, Curt D.; Grossman, Eric E.; Rooney, John J.B.; Conger, Christopher L.; Glenn, Craig

    2004-01-01

    Two reef systems off south Molokai, Hale O Lono and Hikauhi (separated by only 10 km), show strong and fundamental differences in modern ecosystem structure and Holocene accretion history that reflect the influence of wave-induced near-bed shear stresses on reef development in Hawaii. Both sites are exposed to similar impacts from south, Kona, and trade-wind swell. However, the Hale O Lono site is exposed to north swell and the Hikuahi site is not. As a result, the reef at Hale O Lono records no late Holocene net accretion while the reef at Hikauhi records consistent and robust accretion over late Holocene time. Analysis and dating of 24 cores from Hale O Lono and Hikauhi reveal the presence of five major lithofacies that reflect paleo-environmental conditions. In order of decreasing depositional energy they are: (1) coral-algal bindstone; (2) mixed skeletal rudstone; (3) massive coral framestone; (4) unconsolidated floatstone; and (5) branching coral framestone-bafflestone. At Hale O Lono, 10 cores document a backstepping reef ranging from ∼ 8,100 cal yr BP (offshore) to ∼ 4,800 cal yr BP (nearshore). A depauperate community of modern coral diminishes shoreward and seaward of ∼ 15 m depth due to wave energy, disrupted recruitment activities, and physical abrasion. Evidence suggests a change from conditions conducive to accretion during the early Holocene to conditions detrimental to accretion in the late Holocene. Reef structure at Hikauhi, reconstructed from 14 cores, reveals a thick, rapidly accreting and young reef (maximum age ∼ 900 cal yr BP). Living coral cover on this reef increases seaward with distance from the reef crest but terminates at a depth of ∼ 20 m where the reef ends in a large sand field. The primary limitation on vertical reef growth is accommodation space under wave base, not recruitment activities or energy conditions. Interpretations of cored lithofacies suggest that modern reef growth on the southwest corner of Molokai, and by

  13. Black reefs: iron-induced phase shifts on coral reefs

    NARCIS (Netherlands)

    Wegley Kelly, L.; Barott, K.L.; Dinsdale, E.; Friedlander, A.M.; Nosrat, B.; Obura, D.; Sala, E.; Sandin, S.A.; Smith, J.E.; Vermeij, M.J.A.; Williams, G.J.; Willner, D.; Rohwer, F.

    2012-01-01

    The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions of the central Pacific. Natural terrestrial run-off of iron is non-existent and aerial deposition is extremely low. However, a number of ship groundings have occurred on these atolls. The reefs surrounding the

  14. Sewage pollution: mitigation is key for coral reef stewardship.

    Science.gov (United States)

    Wear, Stephanie L; Thurber, Rebecca Vega

    2015-10-01

    Coral reefs are in decline worldwide, and land-derived sources of pollution, including sewage, are a major force driving that deterioration. This review presents evidence that sewage discharge occurs in waters surrounding at least 104 of 112 reef geographies. Studies often refer to sewage as a single stressor. However, we show that it is more accurately characterized as a multiple stressor. Many of the individual agents found within sewage, specifically freshwater, inorganic nutrients, pathogens, endocrine disrupters, suspended solids, sediments, and heavy metals, can severely impair coral growth and/or reproduction. These components of sewage may interact with each other to create as-yet poorly understood synergisms (e.g., nutrients facilitate pathogen growth), and escalate impacts of other, non-sewage-based stressors. Surprisingly few published studies have examined impacts of sewage in the field, but those that have suggest negative effects on coral reefs. Because sewage discharge proximal to sensitive coral reefs is widespread across the tropics, it is imperative for coral reef-focused institutions to increase investment in threat-abatement strategies for mitigating sewage pollution. © 2015 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.

  15. Black reefs: iron-induced phase shifts on coral reefs.

    Science.gov (United States)

    Kelly, Linda Wegley; Barott, Katie L; Dinsdale, Elizabeth; Friedlander, Alan M; Nosrat, Bahador; Obura, David; Sala, Enric; Sandin, Stuart A; Smith, Jennifer E; Vermeij, Mark J A; Williams, Gareth J; Willner, Dana; Rohwer, Forest

    2012-03-01

    The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions of the central Pacific. Natural terrestrial run-off of iron is non-existent and aerial deposition is extremely low. However, a number of ship groundings have occurred on these atolls. The reefs surrounding the shipwreck debris are characterized by high benthic cover of turf algae, macroalgae, cyanobacterial mats and corallimorphs, as well as particulate-laden, cloudy water. These sites also have very low coral and crustose coralline algal cover and are call black reefs because of the dark-colored benthic community and reduced clarity of the overlying water column. Here we use a combination of benthic surveys, chemistry, metagenomics and microcosms to investigate if and how shipwrecks initiate and maintain black reefs. Comparative surveys show that the live coral cover was reduced from 40 to 60% to reefs on Millennium, Tabuaeran and Kingman. These three sites are relatively large (>0.75 km(2)). The phase shift occurs rapidly; the Kingman black reef formed within 3 years of the ship grounding. Iron concentrations in algae tissue from the Millennium black reef site were six times higher than in algae collected from reference sites. Metagenomic sequencing of the Millennium Atoll black reef-associated microbial community was enriched in iron-associated virulence genes and known pathogens. Microcosm experiments showed that corals were killed by black reef rubble through microbial activity. Together these results demonstrate that shipwrecks and their associated iron pose significant threats to coral reefs in iron-limited regions.

  16. State of the coralline reefs

    International Nuclear Information System (INIS)

    Garzon Ferreira, Jaime; Rodriguez Ramirez, Alberto; Bejarano Chavarro, Sonia; Navas Camacho, Raul; Reyes Nivia, Catalina

    2002-01-01

    A diagnosis is made based primarily on the data obtained inside the national system of monitoring of coralline reefs in Colombia, under the coordination of the INVEMAR and with the support of several institutions. The paper does a diagnostic of the covering of the reef substrate, bleaching and coralline illnesses, wealth and abundance of fishes among other topics

  17. Human activities threaten coral reefs

    International Nuclear Information System (INIS)

    Tveitdal, Svein; Bjoerke, Aake

    2002-01-01

    Research indicates that 58 per cent of the coral reefs of the world are threatened by human activities. Pollution and global heating represent some of the threats. Coral reefs just beneath the surface of the sea are very sensitive to temperature changes. Since 1979, mass death of coral reefs has been reported increasingly often. More than 1000 marine species live in the coral reefs, among these are one fourth of all marine species of fish. It is imperative that the coral reefs be preserved, as coastal communities all over the world depend on them as sources of food and as they are the raw materials for important medicines. The article discusses the threats to the coral reefs in general and does not single out any particular energy-related activity as the principal threat. For instance, the El-Nino phenomenon of the Pacific Ocean is probably involved in mass death of coral reefs and in the North Sea large parts of deep-water reefs have been crushed by heavy beam trawlers fishing for bottom fish

  18. Topography and spatial arrangement of reef-building corals on the fringing reefs of North Jamaica may influence their response to disturbance from bleaching.

    Science.gov (United States)

    Crabbe, M J C

    2010-04-01

    Knowledge of factors that are important in reef resilience helps us understand how reefs react following major environmental disturbances such as hurricanes and bleaching. Here we test factors that might have influenced Jamaican reef resilience to, and subsequent recovery from, the 2005 bleaching event, and which might help inform management policy for reefs in the future: reef rugosity and contact of corals with macroalgae. In addition, we test in the field, on Dairy Bull reef, whether aggregated Porites astreoides colonies exhibit enhanced growth when exposed to superior competition from Acopora palmata, as has been found by experiment with the Indo-Pacific corals Porites lobata and the superior competitor Porites rus [Idjadi, J.A., Karlson, R.H., 2007. Spatial arrangement of competitors influences coexistence of reef-building corals. Ecology 88, 2449-2454]. There were significant linear relationships between rugosity and the increase in smallest size classes for Sidastrea siderea, Colpophyllia natans, P. astreoides and Agaricia species, and between rugosity and cover of the branching coral Acropora cervicornis. Linear extension rates of A. cervicornis and radial growth rates of P. astreoides were significantly lower (p6) when in contact with macroalgae. Aggregated colonies of P. astreoides in contact with one another, one of which was in contact with the faster growing competitor A. palmata showed significantly greater growth rates than with just two aggregated P. astreoides colonies alone. These findings suggest that three dimensional topography and complexity is important for reef resilience and viability in the face of environmental stressors such as bleaching. Our findings also support the idea that aggregated spatial arrangements of corals can influence the outcome of interspecific competition and promote species coexistence, important in times of reef recovery after disturbance. Copyright 2009 Elsevier Ltd. All rights reserved.

  19. 40 CFR 230.44 - Coral reefs.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Coral reefs. 230.44 Section 230.44... Aquatic Sites § 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually of calcareous... organisms present in growing portions of the reef. (b) Possible loss of values: The discharge of dredged or...

  20. Spatial competition dynamics between reef corals under ocean acidification

    Science.gov (United States)

    Horwitz, Rael; Hoogenboom, Mia O.; Fine, Maoz

    2017-01-01

    Climate change, including ocean acidification (OA), represents a major threat to coral-reef ecosystems. Although previous experiments have shown that OA can negatively affect the fitness of reef corals, these have not included the long-term effects of competition for space on coral growth rates. Our multispecies year-long study subjected reef-building corals from the Gulf of Aqaba (Red Sea) to competitive interactions under present-day ocean pH (pH 8.1) and predicted end-of-century ocean pH (pH 7.6). Results showed coral growth is significantly impeded by OA under intraspecific competition for five out of six study species. Reduced growth from OA, however, is negligible when growth is already suppressed in the presence of interspecific competition. Using a spatial competition model, our analysis indicates shifts in the competitive hierarchy and a decrease in overall coral cover under lowered pH. Collectively, our case study demonstrates how modified competitive performance under increasing OA will in all likelihood change the composition, structure and functionality of reef coral communities.

  1. Coal ash artificial reef demonstration

    International Nuclear Information System (INIS)

    Livingston, R.J.; Brendel, G.F.; Bruzek, D.A.

    1991-01-01

    This experimental project evaluated the use of coal ash to construct artificial reefs. An artificial reef consisting of approximately 33 tons of cement-stabilized coal ash blocks was constructed in approximately 20 feet of water in the Gulf of Mexico approximately 9.3 miles west of Cedar Key, Florida. The project objectives were: (1) demonstrate that a durable coal ash/cement block can be manufactured by commercial block-making machines for use in artificial reefs, and (2) evaluate the possibility that a physically stable and environmentally acceptable coal ash/cement block reef can be constructed as a means of expanding recreational and commercial fisheries. The reef was constructed in February 1988 and biological surveys were made at monthly intervals from May 1988 to April 1989. The project provided information regarding: Development of an optimum design mix, block production and reef construction, chemical composition of block leachate, biological colonization of the reef, potential concentration of metals in the food web associated with the reef, acute bioassays (96-hour LC 50 ). The Cedar Key reef was found to be a habitat that was associated with a relatively rich assemblage of plants and animals. The reef did not appear to be a major source of heavy metals to species at various levels of biological organization. GAI Consultants, Inc (GAI) of Monroeville, Pennsylvania was the prime consultant for the project. The biological monitoring surveys and evaluations were performed by Environmental Planning and Analysis, Inc. of Tallahassee, Florida. The chemical analyses of biological organisms and bioassay elutriates were performed by Savannah Laboratories of Tallahassee, Florida. Florida Power Corporation of St. Petersburg, Florida sponsored the project and supplied ash from their Crystal River Energy Complex

  2. Earlier (late Pliocene) first appearance of the Caribbean reef-building coral Acropora palmata: Stratigraphic and evolutionary implications

    Science.gov (United States)

    McNeill, Donald F.; Budd, Ann F.; Borne, Pamela F.

    1997-10-01

    An integrated stratigraphic study of reefal deposits on the Caribbean side of the Isthmus of Panama (Limon, Costa Rica) has discovered a significantly earlier first appearance of the major reef-building coral Acropora palmata. A. palmata is here reported from the early late Pliocene, constrained in age to within the Gauss chron (ca. 3.6 2.6 Ma). This coral was previously thought to have originated in the earliest Pleistocene and has subsequently been used as a Quaternary marker throughout the Caribbean and the Bahamas. An earlier appearance in the southern Caribbean implies a diachronous first appearance datum relative to the northern Caribbean. This older age also places A. palmata well within the transition phase of a Pliocene (4 1 Ma) faunal turnover that was marked by widespread extinction and origination of Caribbean coral species. An early late Pliocene origination is coincident with formation of the Isthmus, climate reorganization, and frequent sea-level changes associated with onset of Northern Hemisphere glaciations. The rapid growth and accumulation rates that characterize A. palmata may therefore be adaptive to these fluctuating environmental conditions, enabling its success during the subsequent Pleistocene glacial cycles.

  3. Evidence of exceptional oyster-reef resilience to fluctuations in sea level.

    Science.gov (United States)

    Ridge, Justin T; Rodriguez, Antonio B; Fodrie, F Joel

    2017-12-01

    Ecosystems at the land-sea interface are vulnerable to rising sea level. Intertidal habitats must maintain their surface elevations with respect to sea level to persist via vertical growth or landward retreat, but projected rates of sea-level rise may exceed the accretion rates of many biogenic habitats. While considerable attention is focused on climate change over centennial timescales, relative sea level also fluctuates dramatically (10-30 cm) over month-to-year timescales due to interacting oceanic and atmospheric processes. To assess the response of oyster-reef ( Crassostrea virginica ) growth to interannual variations in mean sea level (MSL) and improve long-term forecasts of reef response to rising seas, we monitored the morphology of constructed and natural intertidal reefs over 5 years using terrestrial lidar. Timing of reef scans created distinct periods of high and low relative water level for decade-old reefs ( n  = 3) constructed in 1997 and 2000, young reefs ( n  = 11) constructed in 2011 and one natural reef (approximately 100 years old). Changes in surface elevation were related to MSL trends. Decade-old reefs achieved 2 cm/year growth, which occurred along higher elevations when MSL increased. Young reefs experienced peak growth (6.7 cm/year) at a lower elevation that coincided with a drop in MSL. The natural reef exhibited considerable loss during the low MSL of the first time step but grew substantially during higher MSL through the second time step, with growth peaking (4.3 cm/year) at MSL, reoccupying the elevations previously lost. Oyster reefs appear to be in dynamic equilibrium with short-term (month-to-year) fluctuations in sea level, evidencing notable resilience to future changes to sea level that surpasses other coastal biogenic habitat types. These growth patterns support the presence of a previously defined optimal growth zone that shifts correspondingly with changes in MSL, which can help guide oyster-reef conservation and

  4. Fish-derived nutrient hotspots shape coral reef benthic communities.

    Science.gov (United States)

    Shantz, Andrew A; Ladd, Mark C; Schrack, Elizabeth; Burkepile, Deron E

    2015-12-01

    Animal-derived nutrients play an important role in structuring nutrient regimes within and between ecosystems. When animals undergo repetitive, aggregating behavior through time, they can create nutrient hotspots where rates of biogeochemical activity are higher than those found in the surrounding environment. In turn, these hotspots can influence ecosystem processes and community structure. We examined the potential for reef fishes from the family Haemulidae (grunts) to create nutrient hotspots and the potential impact of these hotspots on reef communities. To do so, we tracked the schooling locations of diurnally migrating grunts, which shelter at reef sites during the day but forage off reef each night, and measured the impact of these fish schools on benthic communities. We found that grunt schools showed a high degree of site fidelity, repeatedly returning to the same coral heads. These aggregations created nutrient hotspots around coral heads where nitrogen and phosphorus delivery was roughly 10 and 7 times the respective rates of delivery to structurally similar sites that lacked schools of these fishes. In turn, grazing rates of herbivorous fishes at grunt-derived hotspots were approximately 3 times those of sites where grunts were rare. These differences in nutrient delivery and grazing led to distinct benthic communities with higher cover of crustose coralline algae and less total algal abundance at grunt aggregation sites. Importantly, coral growth was roughly 1.5 times greater at grunt hotspots, likely due to the important nutrient subsidy. Our results suggest that schooling reef fish and their nutrient subsidies play an important role in mediating community structure on coral reefs and that overfishing may have important negative consequences on ecosystem functions. As such, management strategies must consider mesopredatory fishes in addition to current protection often offered to herbivores and top-tier predators. Furthermore, our results suggest that

  5. Calcite/aragonite-biocoated artificial coral reefs for marine parks

    Directory of Open Access Journals (Sweden)

    Volodymyr Ivanov

    2017-08-01

    Full Text Available Natural formation of the coral reefs is complicated by slow biomediated precipitation of calcium carbonate from seawater. Therefore, manufactured artificial coral reefs can be used for the formation of “underwater gardens” in marine parks for the recreational fishing and diving that will protect natural coral reefs from negative anthropogenic effects. Additionally, the coating of the concrete, plastic or wooden surfaces of artificial coral reef with calcium carbonate layer could promote attachment and growth of coral larvae and photosynthetic epibiota on these surfaces. Three methods of biotechnological coating of the artificial coral reefs have been tested: (1 microbially induced calcium carbonate precipitation from concentrated calcium chloride solution using live bacterial culture of Bacillus sp. VS1 or dead but urease-active cells of Yaniella sp. VS8; (2 precipitation from calcium bicarbonate solution; (3 precipitation using aerobic oxidation of calcium acetate by bacteria Bacillus ginsengi strain VSA1. The thickness of biotechnologically produced calcium carbonate coating layer was from 0.3 to 3 mm. Biocoating using calcium salt and urea produced calcite in fresh water and aragonite in seawater. The calcium carbonate-coated surfaces were colonized in aquarium with seawater and hard corals as inoculum or in aquarium with fresh water using cyanobacteria Chlorella sorokiana as inoculum. The biofilm on the light-exposed side of calcium carbonate-coated surfaces was formed after six weeks of incubation and developed up to the average thickness of 250 µm in seawater and about 150 µm in fresh water after six weeks of incubation. The biotechnological manufacturing of calcium carbonate-coated concrete, plastic, or wooden surfaces of the structures imitating natural coral reef is technologically feasible. It could be commercially attractive solution for the introduction of aesthetically pleasant artificial coral reefs in marine parks and

  6. Reefs for the future: Resilience of coral reefs in the main Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Declining health of coral reef ecosystems led scientists to search for factors that support reef resilience: the ability of reefs to resist and recover from...

  7. Retrograde Accretion of a Caribbean Fringing Reef Controlled by Hurricanes and Sea-level Rise

    Directory of Open Access Journals (Sweden)

    Paul Blanchon

    2017-10-01

    Full Text Available Predicting the impact of sea-level (SL rise on coral reefs requires reliable models of reef accretion. Most assume that accretion results from vertical growth of coralgal framework, but recent studies show that reefs exposed to hurricanes consist of layers of coral gravel rather than in-place corals. New models are therefore needed to account for hurricane impact on reef accretion over geological timescales. To investigate this geological impact, we report the configuration and development of a 4-km-long fringing reef at Punta Maroma along the northeast Yucatan Peninsula. Satellite-derived bathymetry (SDB shows the crest is set-back a uniform distance of 315 ±15 m from a mid-shelf slope break, and the reef-front decreases 50% in width and depth along its length. A 12-core drill transect constrained by multiple 230Th ages shows the reef is composed of an ~2-m thick layer of coral clasts that has retrograded 100 m over its back-reef during the last 5.5 ka. These findings are consistent with a hurricane-control model of reef development where large waves trip and break over the mid-shelf slope break, triggering rapid energy dissipation and thus limiting how far upslope individual waves can fragment corals and transport clasts. As SL rises and water depth increases, energy dissipation during wave-breaking is reduced, extending the clast-transport limit, thus leading to reef retrogradation. This hurricane model may be applicable to a large sub-set of fringing reefs in the tropical Western-Atlantic necessitating a reappraisal of their accretion rates and response to future SL rise.

  8. The evolution of the Great Barrier Reef during the Last Interglacial Period

    Science.gov (United States)

    Dechnik, Belinda; Webster, Jody M.; Webb, Gregory E.; Nothdurft, Luke; Dutton, Andrea; Braga, Juan-Carlos; Zhao, Jian-xin; Duce, Stephanie; Sadler, James

    2017-02-01

    Reef response to Last Interglacial (LIG) sea level and palaeoenvironmental change has been well documented at a limited number of far-field sites remote from former ice sheets. However, the age and development of LIG reefs in the Great Barrier Reef (GBR) remain poorly understood due to their location beneath modern living reefs. Here we report thirty-nine new mass spectrometry U-Th ages from seven LIG platform reefs across the northern, central and southern GBR. Two distinct geochemical populations of corals were observed, displaying activity ratios consistent with either closed or open system evolution. Our closed-system ages ( 129-126 ka) provide the first reliable LIG ages for the entire GBR. Combined with our open-system model ages, we are able to constrain the interval of significant LIG reef growth in the southern GBR to between 129-121 ka. Using age-elevation data in conjunction with newly defined coralgal assemblages and sedimentary facies analysis we have defined three distinct phases of LIG reef development in response to major sea level and oceanographic changes. These phases include: Phase 1 (> 129 ka), a shallow-water coralgal colonisation phase following initial flooding of the older, likely Marine Isotope Stage 7 (MIS7) antecedent platform; Phase 2 ( 129 ka), a near drowning event in response to rapid sea level rise and greater nutrient-rich upwelling and; Phase 3 ( 128-121 ka), establishment of significant reef framework through catch-up reef growth, initially characterised by deeper, more turbid coralgal assemblages (Phase 3a) that transition to shallow-water assemblages following sea level stabilisation (Phase 3b). Coralgal assemblage analysis indicates that the palaeoenvironments during initial reef growth phases (1 and 2) of the LIG were significantly different than the initial reef growth phases in the Holocene. However, the similar composition of ultimate shallow-water coralgal assemblages and slow reef accretion rates following stabilisation

  9. Hysteresis in coral reefs under macroalgal toxicity and overfishing.

    Science.gov (United States)

    Bhattacharyya, Joydeb; Pal, Samares

    2015-03-01

    Macroalgae and corals compete for the available space in coral reef ecosystems.While herbivorous reef fish play a beneficial role in decreasing the growth of macroalgae, macroalgal toxicity and overfishing of herbivores leads to proliferation of macroalgae. The abundance of macroalgae changes the community structure towards a macroalgae-dominated reef ecosystem. We investigate coral-macroalgal phase shifts by means of a continuous time model in a food chain. Conditions for local asymptotic stability of steady states are derived. It is observed that in the presence of macroalgal toxicity and overfishing, the system exhibits hysteresis through saddle-node bifurcation and transcritical bifurcation. We examine the effects of time lags in the liberation of toxins by macroalgae and the recovery of algal turf in response to grazing of herbivores on macroalgae by performing equilibrium and stability analyses of delay-differential forms of the ODE model. Computer simulations have been carried out to illustrate the different analytical results.

  10. Temporary refugia for coral reefs in a warming world

    Science.gov (United States)

    van Hooidonk, R.; Maynard, J. A.; Planes, S.

    2013-05-01

    Climate-change impacts on coral reefs are expected to include temperature-induced spatially extensive bleaching events. Bleaching causes mortality when temperature stress persists but exposure to bleaching conditions is not expected to be spatially uniform at the regional or global scale. Here we show the first maps of global projections of bleaching conditions based on ensembles of IPCC AR5 (ref. ) models forced with the new Representative Concentration Pathways (RCPs). For the three RCPs with larger CO2 emissions (RCP 4.5, 6.0 and 8.5) the onset of annual bleaching conditions is associated with ~ 510ppm CO2 equivalent; the median year of all locations is 2040 for the fossil-fuel aggressive RCP 8.5. Spatial patterns in the onset of annual bleaching conditions are similar for each of the RCPs. For RCP 8.5, 26% of reef cells are projected to experience annual bleaching conditions more than 5 years later than the median. Some of these temporary refugia include the western Indian Ocean, Thailand, the southern Great Barrier Reef and central French Polynesia. A reduction in the growth of greenhouse-gas emissions corresponding to the difference between RCP 8.5 and 6.0 delays annual bleaching in ~ 23% of reef cells more than two decades, which might conceivably increase the potential for these reefs to cope with these changes.

  11. Late Quaternary changes in climate

    Energy Technology Data Exchange (ETDEWEB)

    Holmgren, K; Karlen, W [Stockholm Univ. (Sweden). Dept. of Physical Geography

    1998-12-01

    This review concerns the Quaternary climate with an emphasis on the last 200 000 years. The present state of art in this field is described and evaluated. The review builds on a thorough examination of classic and recent literature. General as well as detailed patterns in climate are described and the forcing factors and feed-back effects are discussed. Changes in climate occur on all time-scales. During more than 90% of the Quaternary period earth has experienced vast ice sheets, i.e. glaciations have been more normal for the period than the warm interglacial conditions we face today. Major changes in climate, such as the 100 000 years glacial/interglacial cycle, are forced by the Milankovitch three astronomical cycles. Because the cycles have different length climate changes on earth do not follow a simple pattern and it is not possible to find perfect analogues of a certain period in the geological record. Recent discoveries include the observation that major changes in climate seem to occur at the same time on both hemispheres, although the astronomical theory implies a time-lag between latitudes. This probably reflects the influence of feed-back effects within the climate system. Another recent finding of importance is the rapid fluctuations that seem to be a normal process. When earth warmed after the last glaciation temperature jumps of up to 10 deg C occurred within less than a decade and precipitation more than doubled within the same time. The forcing factors behind these rapid fluctuations are not well understood but are believed to be a result of major re-organisations in the oceanic circulation. Realizing that nature, on its own, can cause rapid climate changes of this magnitude put some perspective on the anthropogenic global warming debate, where it is believed that the release of greenhouse gases will result in a global warming of a few C. To understand the forcing behind natural rapid climate changes appears as important as to understand the role

  12. Late Quaternary changes in climate

    International Nuclear Information System (INIS)

    Holmgren, K.; Karlen, W.

    1998-12-01

    This review concerns the Quaternary climate with an emphasis on the last 200 000 years. The present state of art in this field is described and evaluated. The review builds on a thorough examination of classic and recent literature. General as well as detailed patterns in climate are described and the forcing factors and feed-back effects are discussed. Changes in climate occur on all time-scales. During more than 90% of the Quaternary period earth has experienced vast ice sheets, i.e. glaciations have been more normal for the period than the warm interglacial conditions we face today. Major changes in climate, such as the 100 000 years glacial/interglacial cycle, are forced by the Milankovitch three astronomical cycles. Because the cycles have different length climate changes on earth do not follow a simple pattern and it is not possible to find perfect analogues of a certain period in the geological record. Recent discoveries include the observation that major changes in climate seem to occur at the same time on both hemispheres, although the astronomical theory implies a time-lag between latitudes. This probably reflects the influence of feed-back effects within the climate system. Another recent finding of importance is the rapid fluctuations that seem to be a normal process. When earth warmed after the last glaciation temperature jumps of up to 10 deg C occurred within less than a decade and precipitation more than doubled within the same time. The forcing factors behind these rapid fluctuations are not well understood but are believed to be a result of major re-organisations in the oceanic circulation. Realizing that nature, on its own, can cause rapid climate changes of this magnitude put some perspective on the anthropogenic global warming debate, where it is believed that the release of greenhouse gases will result in a global warming of a few C. To understand the forcing behind natural rapid climate changes appears as important as to understand the role

  13. Balance of constructive and destructive carbonate processes on mesophotic coral reefs

    Science.gov (United States)

    Weinstein, D. K.; Klaus, J. S.; Smith, T. B.; Helmle, K. P.; Marshall, D.

    2013-12-01

    Net carbonate accumulation of coral reefs is the product of both constructive and destructive processes that can ultimately influence overall reef geomorphology. Differences in these processes with depth may in part explain why the coral growth-light intensity association does no result in the traditionally theorized reef accretion decrease with depth. Until recently, physical sampling limitations had prevented the acquisition of sedimentary data needed to assess in situ carbonate accumulation in mesophotic reefs (30-150 m). Coral framework production, secondary carbonate production (calcareous encrusters), and bioerosion, the three most critical components of net carbonate accumulation, were analyzed in mesophotic reefs more than 10 km south of St. Thomas, U.S. Virgin Islands along a very gradual slope that limits sediment transport and sedimentation. Recently dead samples of the massive coral, Orbicella annularis collected from three structurally different upper mesophotic coral reef habitats (30-45 m) were cut parallel to the primary growth axis to identify density banding through standard x-radiographic techniques. Assuming annual banding, mesophotic linear extension rates were calculated on the order of 0.7-1.5 mm/yr. Weight change of experimental coral substrates exposed for 3 years indicate differing rates (1.1-17.2 g/yr) of bioerosion and secondary accretion between mesophotic sites. When correcting bioerosion rates for high mesophotic skeletal density, carbonate accumulation rates were found to vary significantly between neighboring mesophotic reefs with distinctive structures. Results imply variable rates of mesophotic reef net carbonate accretion with the potential to influence overall reef/platform morphology, including localized mesophotic reef structure.

  14. Preliminary assessment of bioengineered fringing shoreline reefs in Grand Isle and Breton Sound, Louisiana

    Science.gov (United States)

    La Peyre, Megan K.; Schwarting, Lindsay; Miller, Shea

    2013-01-01

    postconstruction data are available. Data for the latter two sites thus reflect only the 2012 spring/summer seasons, which were further impacted by a direct hit by Hurricane Isaac in August 2012, which resulted in shoreward movement of approximately 14 percent of the bioengineered structures at Lake Fortuna. Given the shortened monitoring timeframe and significant differences in construction schedules, we were not able to provide a full postconstruction assessment of the sites or a full comparison of site success based on local site characteristics. Because many of the impacts that were identified for monitoring reflect long-term processes, results and data presented should be interpreted cautiously. Sustainable oyster reefs require recruitment, growth, and survival at a rate that keeps pace with mortality and shell disarticulation. Although one site failed to recruit (establishment plus survival > 50 millimeters [mm]) over two spawning seasons, two sites only had 6 months postconstruction data available for assessment. Although there are good data on the requirements for oyster growth, there is limited explicit information on the site-specific water quality, hydrodynamic, and biological interaction effects that may determine successful reef establishment. Furthermore, interannual variability can significantly affect reef establishment, and our shortened timeframe of sampling (less than one spawning season for two of the reefs; two spawning seasons for one reef), combined with a lack of prerestoration monitoring data, limit our ability to draw any conclusions about long-term reef sustainability. Bioengineered reefs are thought to provide some benefits to shoreline stabilization through their structure by immediately attenuating wave energies and directly reducing erosion rates at shorelines sheltered by the reefs but also by increasing sediment deposition behind the reefs. Preliminary data indicate differences in reef impact by site; given the short timeframe of postconstruction

  15. Spatial variations in density and size of the echinoid Diadema antillarum Philippi on some Venezuelan coral reefs

    NARCIS (Netherlands)

    Weil, Ernesto; Losada, Freddy; Bone, David

    1984-01-01

    The distribution, population density and size structure of Diadema antillarum Philippi was found to vary with reef locality, food availability and the structural complexity of the reef. Structural complexity was classified according to the growth morphology and abundance of the coral species found

  16. Antibacterial Activity of Orthodontic Cement Containing Quaternary Ammonium Polyethylenimine Nanoparticles Adjacent to Orthodontic Brackets

    OpenAIRE

    Eldad Sharon; Revital Sharabi; Adi Eden; Asher Zabrovsky; Gilad Ben-Gal; Esi Sharon; Yoav Pietrokovski; Yael Houri-Haddad; Nurit Beyth

    2018-01-01

    Enamel demineralization is a common problem found in patients using orthodontic devices, such as orthodontic braces. It was found that Streptoccocus mutans growth increases adjacent to orthodontic devices, which may result in caries development. Incorporated antibacterial quaternary ammonium polyethylenimine (QPEI) nanoparticles were previously shown to be highly efficacious against various bacteria. Combining antibacterial materials in orthodontic cement may be advantageous to prevent bacter...

  17. Distribution of Georgia Oyster Reefs

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The feature class in this ESRI Geodatabase contains polygons representing oyster reefs along the Georgia coastal waterways from Chatham County south to Glynn County....

  18. Tortugas Reef Fish Census (CRCP)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a long term data set collecting visual census transect data on reef fishes at staions located at Rileys Hump, Tortugas South Ecological Reservee.

  19. Carrying capacity of coral reefs

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.

    The sustainable yield of a commercially exploited fishery is assessed by the biological and environmental factors (including fishing effort). These parameters with a reef are vastly diverse-size, location, species diversity, productivity type...

  20. Coral Reef Protection Implementation Plan

    National Research Council Canada - National Science Library

    Lobel, Lisa

    2000-01-01

    This document identify policies and actions to implement the Department of Defense's responsibilities under Executive Order 13089 on Coral Reef Protection, and are a requirement of the interim Task...

  1. Drowning of the - 150 m reef off Hawaii: A casualty of global meltwater pulse 1A?

    Science.gov (United States)

    Webster, J.M.; Clague, D.A.; Riker-Coleman, K.; Gallup, C.; Braga, J.C.; Potts, D.; Moore, J.G.; Winterer, E.L.; Paull, C.K.

    2004-01-01

    We present evidence that the drowning of the - 150 m coral reef around Hawaii was caused by rapid sea-level rise associated with meltwater pulse 1A (MWP-1A) during the last deglaciation. New U/Th and 14C accelerator mass spectrometry dates, combined with reinterpretation of existing radiometric dates, constrain the age of the coral reef to 15.2-14.7 ka (U/Th age), indicating that reef growth persisted for 4.3 k.y. following the end of the Last Glacial Maximum at 19 ka. The drowning age of the reef is roughly synchronous with the onset of MWP-1A between 14.7 and 14.2 ka. Dates from coralline algal material range from 14 to 10 cal ka (calibrated radiocarbon age), 1-4 k.y. younger than the coral ages. A paleoenvironmental reconstruction incorporating all available radiometric dates, high-resolution bathymetry, dive observations, and coralgal paleobathymetry data indicates a dramatic rise in sea level around Hawaii ca. 14.7 ka. Paleowater depths over the reef crest increased rapidly above a critical depth (30-40 m), drowning the shallow reef-building Porites corals and causing a shift to deepwater coralline algal growth, preserved as a crust on the drowned reef crest. ?? 2004 Geological Society of America.

  2. Coral reef bleaching: ecological perspectives

    Science.gov (United States)

    Glynn, P. W.

    1993-03-01

    Coral reef bleaching, the whitening of diverse invertebrate taxa, results from the loss of symbiotic zooxanthellae and/or a reduction in photosynthetic pigment concentrations in zooxanthellae residing within the gastrodermal tissues of host animals. Of particular concern are the consequences of bleaching of large numbers of reef-building scleractinian corals and hydrocorals. Published records of coral reef bleaching events from 1870 to the present suggest that the frequency (60 major events from 1979 to 1990), scale (co-occurrence in many coral reef regions and often over the bathymetric depth range of corals) and severity (>95% mortality in some areas) of recent bleaching disturbances are unprecedented in the scientific literature. The causes of small scale, isolated bleaching events can often be explained by particular stressors (e.g., temperature, salinity, light, sedimentation, aerial exposure and pollutants), but attempts to explain large scale bleaching events in terms of possible global change (e.g., greenhouse warming, increased UV radiation flux, deteriorating ecosystem health, or some combination of the above) have not been convincing. Attempts to relate the severity and extent of large scale coral reef bleaching events to particular causes have been hampered by a lack of (a) standardized methods to assess bleaching and (b) continuous, long-term data bases of environmental conditions over the periods of interest. An effort must be made to understand the impact of bleaching on the remainder of the reef community and the long-term effects on competition, predation, symbioses, bioerosion and substrate condition, all factors that can influence coral recruitment and reef recovery. If projected rates of sea warming are realized by mid to late AD 2000, i.e. a 2°C increase in high latitude coral seas, the upper thermal tolerance limits of many reef-building corals could be exceeded. Present evidence suggests that many corals would be unable to adapt

  3. National Coral Reef Monitoring Program: Coral Reef Fish collected in Fl Keys Reef Tract (2014)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Divers conducted reef visual census (RVC) fish surveys and habitat assessments at 433 sites in the Florida Keys, 436 sites in the Dry Tortugas and 320 sites in the...

  4. The coral reef of South Moloka'i, Hawai'i - Portrait of a sediment-threatened fringing reef

    Science.gov (United States)

    Field, Michael E.; Cochran, Susan A.; Logan, Joshua; Storlazzi, Curt D.

    2008-01-01

    Moloka‘i, with the most extensive coral reef in the main Hawaiian Islands, is especially sacred to Hina, the Goddess of the Moon. As Hinaalo, she is the Mother of the Hawaiian people; as Hinapuku‘a, she is the Goddess of Fishermen; and in the form Hina‘opuhalako‘a, she is the Goddess who gave birth to coral, coral reefs, and all spiny marine organisms. Interdependence between the reef’s living resources, the people, and their cosmology was the basis for management of Moloka‘i’s coastal waters for over a thousand years.The ancient residents of Moloka‘i built the greatest concentration of fishponds known anywhere, but their mastery of mariculture, something needed now more than ever, was lost after near genocide from exotic Western diseases. Subsequent destruction of the native vegetation for exotic cattle, goats, pigs, sugar cane, and pineapple caused soil erosion and sedimentation on the reef flat. This masterful volume clearly documents that soil washing into the sea is the major threat to the reef today. Abandoned fishponds, choked with sediment, now act as barriers and mud traps, making damage to corals less than it would otherwise would have been.The role of mud and freshwater from land in preventing coral reef growth, clearly articulated in Charles Darwin’s first book, The Structure and Distribution of Coral Reefs, is the major theme of this book. All around the tropics, coral reefs have died from huge increases in terrestrial sedimentation that resulted from destruction of hillside forests for cash-crop agriculture and pastures in the colonial era, especially in Latin America, Asia, and the islands of the Caribbean and Indo-Pacific. It is obvious that one cannot manage the coastal zone as a unit separate from the watersheds that drain into it. Yet there has been surprisingly little comprehensive scientific study of these impacts.In this landmark volume, U.S. Geological Survey researchers and their colleagues have developed and applied a

  5. Indirect effects of overfishing on Caribbean reefs: sponges overgrow reef-building corals.

    Science.gov (United States)

    Loh, Tse-Lynn; McMurray, Steven E; Henkel, Timothy P; Vicente, Jan; Pawlik, Joseph R

    2015-01-01

    Consumer-mediated indirect effects at the community level are difficult to demonstrate empirically. Here, we show an explicit indirect effect of overfishing on competition between sponges and reef-building corals from surveys of 69 sites across the Caribbean. Leveraging the large-scale, long-term removal of sponge predators, we selected overfished sites where intensive methods, primarily fish-trapping, have been employed for decades or more, and compared them to sites in remote or marine protected areas (MPAs) with variable levels of enforcement. Sponge-eating fishes (angelfishes and parrotfishes) were counted at each site, and the benthos surveyed, with coral colonies scored for interaction with sponges. Overfished sites had >3 fold more overgrowth of corals by sponges, and mean coral contact with sponges was 25.6%, compared with 12.0% at less-fished sites. Greater contact with corals by sponges at overfished sites was mostly by sponge species palatable to sponge predators. Palatable species have faster rates of growth or reproduction than defended sponge species, which instead make metabolically expensive chemical defenses. These results validate the top-down conceptual model of sponge community ecology for Caribbean reefs, as well as provide an unambiguous justification for MPAs to protect threatened reef-building corals. An unanticipated outcome of the benthic survey component of this study was that overfished sites had lower mean macroalgal cover (23.1% vs. 38.1% for less-fished sites), a result that is contrary to prevailing assumptions about seaweed control by herbivorous fishes. Because we did not quantify herbivores for this study, we interpret this result with caution, but suggest that additional large-scale studies comparing intensively overfished and MPA sites are warranted to examine the relative impacts of herbivorous fishes and urchins on Caribbean reefs.

  6. The Biology and Economics of Coral Growth

    NARCIS (Netherlands)

    Osinga, R.; Schutter, M.; Griffioen, B.; Wijffels, R.H.; Verreth, J.A.J.; Shafit, S.; Henard, S.; Taruffi, M.; Gili, C.; Lavorano, S.

    2011-01-01

    To protect natural coral reefs, it is of utmost importance to understand how the growth of the main reef-building organisms-the zooxanthellate scleractinian corals-is controlled. Understanding coral growth is also relevant for coral aquaculture, which is a rapidly developing business. This review

  7. Effects of Great Barrier Reef degradation on recreational reef-trip demand: a contingent behaviour approach

    NARCIS (Netherlands)

    Kragt, M.E.; Roebeling, P.C.; Ruijs, A.J.W.

    2009-01-01

    There is a growing concern that increased nutrient and sediment runoff from river catchments are a potential source of coral reef degradation. Degradation of reefs may affect the number of tourists visiting the reef and, consequently, the economic sectors that rely on healthy reefs for their income

  8. Climate predictors of late quaternary extinctions

    DEFF Research Database (Denmark)

    Nogués-Bravo, David; Ohlemüller, Ralf; Batra, Persaram

    2010-01-01

    Between 50,000 and 3,000 years before present (BP) 65% of mammal genera weighing over 44 kg went extinct, together with a lower proportion of small mammals. Why species went extinct in such large numbers is hotly debated. One of the arguments proposes that climate changes underlie Late Quaternary...... extinctions, but global quantitative evidence for this hypothesis is still lacking. We test the potential role of global climate change on the extinction of mammals during the Late Quaternary. Our results suggest that continents with the highest climate footprint values, in other words, with climate changes...... of greater magnitudes during the Late Quaternary, witnessed more extinctions than continents with lower climate footprint values, with the exception of South America. Our results are consistent across species with different body masses, reinforcing the view that past climate changes contributed to global...

  9. Response of reef corals on a fringing reef flat to elevated suspended-sediment concentrations: Moloka‘i, Hawai‘i

    Science.gov (United States)

    Jokiel, Paul L.; Rodgers, Ku'ulei S.; Storlazzi, Curt D.; Field, Michael E.; Lager, Claire V.; Lager, Dan

    2014-01-01

    A long-term (10 month exposure) experiment on effects of suspended sediment on the mortality, growth, and recruitment of the reef corals Montipora capitata and Porites compressa was conducted on the shallow reef flat off south Molokaʻi, Hawaiʻi. Corals were grown on wire platforms with attached coral recruitment tiles along a suspended solid concentration (SSC) gradient that ranged from 37 mg l−1 (inshore) to 3 mg l−1(offshore). Natural coral reef development on the reef flat is limited to areas with SSCs less than 10 mg l−1 as previously suggested in the scientific literature. However, the experimental corals held at much higher levels of turbidity showed surprisingly good survivorship and growth. High SSCs encountered on the reef flat reduced coral recruitment by one to three orders of magnitude compared to other sites throughout Hawaiʻi. There was a significant correlation between the biomass of macroalgae attached to the wire growth platforms at the end of the experiment and percentage of the corals showing mortality. We conclude that lack of suitable hard substrate, macroalgal competition, and blockage of recruitment on available substratum are major factors accounting for the low natural coral coverage in areas of high turbidity. The direct impact of high turbidity on growth and mortality is of lesser importance.

  10. PRN 88-2: Clustering of Quaternary Ammonium Compounds

    Science.gov (United States)

    This Notice announces that EPA has clustered the Quaternary Ammonium Compounds into four groups for the purpose of testing chemicals to build a database that will support continued registration of the entire family of quaternary ammonium compounds

  11. Quaternary sediments in Rybalsryi quarry of Dnipropetrovsk

    Directory of Open Access Journals (Sweden)

    Manyuk V.V.

    2014-12-01

    Full Text Available The results of a study of the typical section of Quaternary sediments in the Rybalske quarry and first time been reported to shift to the South boundary of the spread of the Dneprovian ice cover. Long-term observation of the geological structure subaerial and subaqueous deposits in Quaternary escarpment quarry clearly demonstrates the exceptional value, integrity, and at the same time, a certain exclusivity individual elements Quaternary section. Middle-upper Pleistocene section of substantially exceeds disclosed in Sazhovka draw, where the stratotype Kodatskiy fossil soil and elevated section of Quaternary sediments. If old Kodak can see only fragments section, an opened side by deep ravines and conditions of use cleared, the Rybalske quarry ledge submitted in one complete section alternation fossil soil horizons and loess - loess from the Dnieper to the modern black soil, and another ledge next to, well the rest of the section is exposed (from Tilihulske to Shyrokynske klimatolite. Established that among the many famous sections subaerial deposits located in the Middle Dnieper in the north-eastern part of the Dnieper-Donets basin, in the Black Sea and the Crimea and studied by the author in different years, and described loess and soil horizons (from the Black Sea to the Dnieper differ markedly lack of connectivity, flowability and friability. It is logical to assume that lithofacies conditions of the thicker subaerial deposits in the wellhead part Samara, where the Rybalske quarry markedly different from existing in these areas. Despite the obvious influence of the Dnieper glacier, direct signs which surround Dnipropetrovs’k north must be other reasons not yet explored. It is worth noting another important feature of the section of Quaternary sediments in fishing career. The above section is characteristic of the north-eastern part of the quarry, while the north, at higher marks of the watershed in the lower parts of thicker Quaternary

  12. Status of coral reefs of India

    Digital Repository Service at National Institute of Oceanography (India)

    Muley, E.V.; Venkataraman, K.; Alfred, J.R.B.; Wafar, M.V.M.

    and economic significance of coral reefs and the threat perceptions, Government of India has initiated measures for their intensive conservation and management. Present paper deals with ecological status of coral reefs in the country and various national...

  13. Biology of corals and coral reefs

    Digital Repository Service at National Institute of Oceanography (India)

    Rajkumar, R.; Parulekar, A.H.

    on the systematic position is presented. The general structure is depicted with illustrations. Physiology part is updated to current knowledge on reproduction, nutrition and excretion of corals. The coral reefs section begins with status of world reefs...

  14. Sabellaria spinulosa (Polychaeta, Annelida) reefs in the Mediterranean Sea: Habitat mapping, dynamics and associated fauna for conservation management

    Science.gov (United States)

    Gravina, Maria Flavia; Cardone, Frine; Bonifazi, Andrea; Bertrandino, Marta Simona; Chimienti, Giovanni; Longo, Caterina; Marzano, Carlotta Nonnis; Moretti, Massimo; Lisco, Stefania; Moretti, Vincenzo; Corriero, Giuseppe; Giangrande, Adriana

    2018-01-01

    Bio-constructions by Sabellaria worms play a key functional role in the coastal ecosystems being an engineer organism and for this reason are the object of protection. The most widespread reef building species along Atlantic and Mediterranean coasts is S. alveolata (L.), while the aggregations of S. spinulosa are typically limited to the North Sea coasts. This paper constitutes the first detailed description of unusual large S. spinulosa reefs in the Mediterranean Sea. Defining current health status and evaluating the most important threats and impacts is essential to address conservation needs and design management plans for these large biogenic structures. Present knowledge on Mediterranean reefs of S. alveolata is fragmentary compared to Northeast Atlantic reefs, and concerning S. spinulosa, this paper represents a focal point in the knowledge on Mediterranean reefs of this species. A one-year study on temporal changes in reef structure and associated fauna is reported. The annual cycle of S. spinulosa reef shows a spawning event in winter-early spring, a period of growth and tubes aggregation from spring-early summer to autumn and a degeneration phase in winter. The variations exhibited in density of the worm aggregation and the changes in the reef elevation highlight a decline and regeneration of the structure over a year. The many ecological roles of the S. spinulosa reef were mainly in providing a diversity of microhabitats hosting hard and sandy bottom species, sheltering rare species, and producing biogenic structures able to provide coastal protection. The Mediterranean S. spinulosa reef does not shelter a distinctive associated fauna; however the richness in species composition underscores the importance of the reef as a biodiversity hot-spot. Finally, the roles of the biogenic formations and their important biotic and physical dynamics support the adoption of strategies for conservation of Mediterranean S.spinulosa reefs, according to the aims of the

  15. Transport of Calcareous Fragments by Reef Fishes.

    Science.gov (United States)

    Bardach, J E

    1961-01-13

    The weight of sand, coral scrapings, algal fragments, and other calcareous materials which pass through the intestines of reef fishes was calculated on a hectare-per-year basis. It was found that browsing omnivorous reef fishes which rely, in part, on a plant diet ingested and redeposited at least 2300 kg of such material on a 1-hectare study reef near Bermuda. Reasons are presented why this estimate, certainly in order of magnitude, should be applicable to coral reefs in general.

  16. Understanding Coral Reef Fish Characteristics Using Videogrammetry in Hanauma and Maunalua Bays, Oahu, Hawaii during 2007 (NODC Accession 0042353)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Videogrammetry data taken in 2007 are used for a study of fish within coral reef ecosystems. We attempted to generate or find information on abundance, growth,...

  17. Photography of Coral Reefs from ISS

    Science.gov (United States)

    Robinson, Julie A.

    2009-01-01

    This viewgraph presentation reviews the uses of photography from the International Space Station (ISS) in studying Earth's coral reefs. The photographs include reefs in various oceans . The photographs have uses for science in assisting NASA mapping initiatives, distribution worldwide through ReefBase, and by biologist in the field.

  18. Synergistic impacts of global warming on the resilience of coral reefs

    Science.gov (United States)

    Bozec, Yves-Marie; Mumby, Peter J.

    2015-01-01

    Recent epizootics have removed important functional species from Caribbean coral reefs and left communities vulnerable to alternative attractors. Global warming will impact reefs further through two mechanisms. A chronic mechanism reduces coral calcification, which can result in depressed somatic growth. An acute mechanism, coral bleaching, causes extreme mortality when sea temperatures become anomalously high. We ask how these two mechanisms interact in driving future reef state (coral cover) and resilience (the probability of a reef remaining within a coral attractor). We find that acute mechanisms have the greatest impact overall, but the nature of the interaction with chronic stress depends on the metric considered. Chronic and acute stress act additively on reef state but form a strong synergy when influencing resilience by intensifying a regime shift. Chronic stress increases the size of the algal basin of attraction (at the expense of the coral basin), whereas coral bleaching pushes the system closer to the algal attractor. Resilience can change faster—and earlier—than a change in reef state. Therefore, we caution against basing management solely on measures of reef state because a loss of resilience can go unnoticed for many years and then become disproportionately more difficult to restore.

  19. Development of Miocene-Pliocene reef trend, St. Croix, U. S. Virgin Islands

    Energy Technology Data Exchange (ETDEWEB)

    Gill, I.; Eby, D.E.; Hubbard, D.K.; Frost, S.H.

    1988-01-01

    The Miocene-Pliocene reef trend on St. Croix, U.S. Virgin Islands, rims the present southern western coasts of the island and includes accompanying lagoonal and forereef facies. The reef trend was established on a foram-algal bank facies that represents basinal shallowing from the deep-water pelagic and hemipelagic facies of the Miocene Kingshill Limestone. Information on facies distribution and thickness is derived from rock exposures and 22 test wells drilled to a maximum depth of 91 m. The greatest thickness of the reef facies exists in a subsidiary graben on the south coast of St. Croix. The thickness of the reef section in this locality is due to preservation of the section in a downdropped block. Reef faunas include extant corals, as well as several extinct genera. Extant corals (e.g. Montastrea annularis, Diploria sp., and Porites porites) and extinct corals (e.g., Stylophora affinis, Antillea bilobata, and Thysanus sp.) are the main reef frame-builders. Coralline algea and large benthic foraminifera are significant contributors to the sediments both prior to and during scleractinian reef growth. Dolomitization and calcite cementation occur prominantly in an area corresponding to a Holocene lagoon. The spatial distribution of the dolomite suggests that the lagoon is a Tertiary feature directly related to the dolomitization process. Stable isotopic values suggest dolomitization of fluids of elevated salinity.

  20. The impacts of tourism on coral reef conservation awareness and support in coastal communities in Belize

    Science.gov (United States)

    Diedrich, A.

    2007-12-01

    Marine recreational tourism is one of a number of threats to the Belize Barrier Reef but, conversely, represents both a motivation and source of resources for its conservation. The growth of tourism in Belize has resulted in the fact that many coastal communities are in varying stages of a socio-economic shift from dependence on fishing to dependence on tourism. In a nation becoming increasingly dependent on the health of its coral reef ecosystems for economic prosperity, a shift from extractive uses to their preservation is both necessary and logical. Through examining local perception data in five coastal communities in Belize, each attracting different levels of coral reef related tourism, this analysis is intended to explore the relationship between tourism development and local coral reef conservation awareness and support. The results of the analysis show a positive correlation between tourism development and coral reef conservation awareness and support in the study communities. The results also show a positive correlation between tourism development and local perceptions of quality of life, a trend that is most likely the source of the observed relationship between tourism and conservation. The study concludes that, because the observed relationship may be dependent on continued benefits from tourism as opposed to a perceived crisis in coral reef health, Belize must pay close attention to tourism impacts in the future. Failure to do this could result in a destructive feedback loop that would contribute to the degradation of the reef and, ultimately, Belize’s diminished competitiveness in the ecotourism market.

  1. Quantifying and Valuing Potential Climate Change Impacts on Coral Reefs in the United States

    Science.gov (United States)

    Wobus, C. W.; Lane, D.; Buddemeier, R. W.; Ready, R. C.; Shouse, K. C.; Martinich, J.

    2012-12-01

    Global climate change presents a two-pronged threat to coral reef ecosystems: increasing sea surface temperatures will increase the likelihood of episodic bleaching events, while increasing ocean carbon dioxide concentrations will change the carbonate chemistry that drives coral growth. Because coral reefs have important societal as well as ecological benefits, climate change mitigation policies that ameliorate these impacts may create substantial economic value. We present a model that evaluates both the ecological and the economic impacts of climate change on coral reefs in the United States. We use a coral reef mortality and bleaching model to project future coral reef declines under a range of climate change policy scenarios for south Florida, Puerto Rico and Hawaii. Using a benefits transfer approach, the outputs from the physical model are then used to quantify the economic impacts of these coral reef declines for each of these regions. We find that differing climate change trajectories create substantial changes in projected coral cover and value for Hawaii, but that the ecological and economic benefits of more stringent emissions scenarios are less clear for Florida and Puerto Rico. Overall, our results indicate that the effectiveness of climate change mitigation policies may be region-specific, but that these policies could result in a net increase of nearly $10 billion in economic value from coral reef-related recreational activities alone, over the 21st century.

  2. Ocean acidification and calcifying reef organisms: a mesocosm investigation

    Science.gov (United States)

    Jokiel, P. L.; Rodgers, K. S.; Kuffner, I. B.; Andersson, A. J.; Cox, E. F.; MacKenzie, F. T.

    2008-09-01

    A long-term (10 months) controlled experiment was conducted to test the impact of increased partial pressure of carbon dioxide ( pCO2) on common calcifying coral reef organisms. The experiment was conducted in replicate continuous flow coral reef mesocosms flushed with unfiltered sea water from Kaneohe Bay, Oahu, Hawaii. Mesocosms were located in full sunlight and experienced diurnal and seasonal fluctuations in temperature and sea water chemistry characteristic of the adjacent reef flat. Treatment mesocosms were manipulated to simulate an increase in pCO2 to levels expected in this century [midday pCO2 levels exceeding control mesocosms by 365 ± 130 μatm (mean ± sd)]. Acidification had a profound impact on the development and growth of crustose coralline algae (CCA) populations. During the experiment, CCA developed 25% cover in the control mesocosms and only 4% in the acidified mesocosms, representing an 86% relative reduction. Free-living associations of CCA known as rhodoliths living in the control mesocosms grew at a rate of 0.6 g buoyant weight year-1 while those in the acidified experimental treatment decreased in weight at a rate of 0.9 g buoyant weight year-1, representing a 250% difference. CCA play an important role in the growth and stabilization of carbonate reefs, so future changes of this magnitude could greatly impact coral reefs throughout the world. Coral calcification decreased between 15% and 20% under acidified conditions. Linear extension decreased by 14% under acidified conditions in one experiment. Larvae of the coral Pocillopora damicornis were able to recruit under the acidified conditions. In addition, there was no significant difference in production of gametes by the coral Montipora capitata after 6 months of exposure to the treatments.

  3. Ocean acidification and calcifying reef organisms: A mesocosm investigation

    Science.gov (United States)

    Jokiel, P.L.; Rodgers, K.S.; Kuffner, I.B.; Andersson, A.J.; Cox, E.F.; MacKenzie, F.T.

    2008-01-01

    A long-term (10 months) controlled experiment was conducted to test the impact of increased partial pressure of carbon dioxide (pCO2) on common calcifying coral reef organisms. The experiment was conducted in replicate continuous flow coral reef mesocosms flushed with unfiltered sea water from Kaneohe Bay, Oahu, Hawaii. Mesocosms were located in full sunlight and experienced diurnal and seasonal fluctuations in temperature and sea water chemistry characteristic of the adjacent reef flat. Treatment mesocosms were manipulated to simulate an increase in pCO2 to levels expected in this century [midday pCO2 levels exceeding control mesocosms by 365 ?? 130 ??atm (mean ?? sd)]. Acidification had a profound impact on the development and growth of crustose coralline algae (CCA) populations. During the experiment, CCA developed 25% cover in the control mesocosms and only 4% in the acidified mesocosms, representing an 86% relative reduction. Free-living associations of CCA known as rhodoliths living in the control mesocosms grew at a rate of 0.6 g buoyant weight year-1 while those in the acidified experimental treatment decreased in weight at a rate of 0.9 g buoyant weight year-1, representing a 250% difference. CCA play an important role in the growth and stabilization of carbonate reefs, so future changes of this magnitude could greatly impact coral reefs throughout the world. Coral calcification decreased between 15% and 20% under acidified conditions. Linear extension decreased by 14% under acidified conditions in one experiment. Larvae of the coral Pocillopora damicornis were able to recruit under the acidified conditions. In addition, there was no significant difference in production of gametes by the coral Montipora capitata after 6 months of exposure to the treatments. ?? 2008 Springer-Verlag.

  4. Pleistocene corals of the Florida keys: Architects of imposing reefs - Why?

    Science.gov (United States)

    Lidz, B.H.

    2006-01-01

    Five asymmetrical, discontinuous, stratigraphically successive Pleistocene reef tracts rim the windward platform margin off the Florida Keys. Built of large head corals, the reefs are imposing in relief (???30 m high by 1 km wide), as measured from seismic profiles. Well dated to marine oxygen isotope substages 5c, 5b, and 5a, corals at depth are inferred to date to the Stage 6/5 transition. The size of these reefs attests to late Pleistocene conditions that repeatedly induced vigorous and sustained coral growth. In contrast, the setting today, linked to Florida Bay and the Gulf of Mexico, is generally deemed marginal for reef accretion. Incursion onto the reef tract of waters that contain seasonally inconsistent temperature, salinity, turbidity, and nutrient content impedes coral growth. Fluctuating sea level and consequent settings controlled deposition. The primary dynamic was position of eustatic zeniths relative to regional topographic elevations. Sea level during the past 150 ka reached a maximum of ???10.6 m higher than at present ???125 ka, which gave rise to an inland coral reef (Key Largo Limestone) and ooid complex (Miami Limestone) during isotope substage 5e. These formations now form the Florida Keys and a bedrock ridge beneath The Quicksands (Gulf of Mexico). High-precision radiometric ages and depths of dated corals indicate subsequent apices remained ???15 to 9 m, respectively, below present sea level. Those peaks provided accommodation space sufficient for vertical reef growth yet exposed a broad landmass landward of the reefs for >100 ka. With time, space, lack of bay waters, and protection from the Gulf of Mexico, corals thrived in clear oceanic waters of the Gulf Stream, the only waters to reach them.

  5. Sedimentary and environmental history of the Late Permian Bonikowo Reef (Zechstein Limestone, Wuchiapingian, western Poland

    Directory of Open Access Journals (Sweden)

    Paweł Raczyński

    2017-07-01

    Full Text Available The Bonikowo Reef occurs in the central part of the Zechstein Limestone Basin in western Poland and was growing on the topmost edges of tilted blocks and/or on the top of uplifted horsts of the Brandenburg–Wolsztyn–Pogorzela High. Its size is ca. 1.6 km2. The Bonikowo Reef shows the thickest reef section (90.5 m recorded in the High. The Zechstein Limestone unit is represented mostly by limestones, often thoroughly recrystallized, although the macrotextures and biota of the boundstone are identifiable in most cases. The drillcore section is a mixture of boundstones (microbial and bryozoan, wackestones, packstones and grainstones, which often co-occur. The δ13C and δ18O values for both calcite (avg. 3.8 ± 0.8‰ and −3.4 ± 1.7‰, respectively and dolomite (avg. 3.5 ± 0.7‰ and −5.2 ± 1.3‰, respectively are transitional between the values previously reported for condensed sequences of the basinal facies and larger reef complexes. The biofacies of the Bonikowo Reef are very similar to those recognized in other reefs of the Brandenburg–Wolsztyn–Pogorzela High, which owe their origin to the destruction of bryozoan boundstones. The biota composition is typical and characteristic of other Zechstein Limestone reefs. However, the Bonikowo Reef demonstrates the importance of microbialites, laminar and nodose encrustations, in the growth and cohesion of the Zechstein Limestone reefs. Such encrustations abound within the Zechstein Limestone although, in many cases, the real nature of the encrustations is difficult to ascertain. These laminated encrustations show great similarity to Archaeolithoporella that is one of the most important Permian reef-building organisms. The encrustations considered to represent Archaeolithoporella were also previously recorded in the Zechstein Limestone of western Poland and in its stratigraphic equivalent, the Middle Magnesian Limestone of Northeast England. The lower part of the sequence shows

  6. Synthesis and antibacterial activity screening of quaternary ...

    Indian Academy of Sciences (India)

    A series of quaternary ammonium derivatives of triazolyl pyranochromen-2-ones have been synthesized and characterized; their antibacterial potential were investigated against two gram negative (Pseudomonas aeruginosa and Escherichia coli) and two gram positive bacterial strains (Bacillus cereus and Staphylococcus ...

  7. The Plio-Quaternary Magdalena Turbidite System

    OpenAIRE

    Estrada, Ferran; Alonso, Belén; Ercilla, Gemma

    2011-01-01

    2006. Estrada F., Alonso B., Ercilla G. The Plio-Quaternary Magdalena Turbidite System. SEPM/Geological Society of London conference “External Controls on Deepwater Depositional Systems”, to be held at the Geological Society in Piccadilly, London, March 27th to 29th.

  8. Palladium-Catalyzed Asymmetric Quaternary Stereocenter Formation

    NARCIS (Netherlands)

    Gottumukkala, Aditya L.; Matcha, Kiran; Lutz, Martin; de Vries, Johannes G.; Minnaard, Adriaan J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of beta,beta-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and

  9. Palladium-catalyzed asymmetric quaternary stereocenter formation

    NARCIS (Netherlands)

    Gottumukkala, A.L.; Matcha, K.; Lutz, M.; de Vries, J.G.; Minnaard, A.J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and provides

  10. Fire coral clones demonstrate phenotypic plasticity among reef habitats.

    Science.gov (United States)

    Dubé, Caroline E; Boissin, Emilie; Maynard, Jeffrey A; Planes, Serge

    2017-08-01

    Clonal populations are often characterized by reduced levels of genotypic diversity, which can translate into lower numbers of functional phenotypes, both of which impede adaptation. Study of partially clonal animals enables examination of the environmental settings under which clonal reproduction is favoured. Here, we gathered genotypic and phenotypic information from 3,651 georeferenced colonies of the fire coral Millepora platyphylla in five habitats with different hydrodynamic regimes in Moorea, French Polynesia. In the upper slope where waves break, most colonies grew as vertical sheets ("sheet tree") making them more vulnerable to fragmentation. Nearly all fire corals in the other habitats are encrusting or massive. The M. platyphylla population is highly clonal (80% of the colonies are clones), while characterized by the highest genotype diversity ever documented for terrestrial or marine populations (1,064 genotypes). The proportion of clones varies greatly among habitats (≥58%-97%) and clones (328 clonal lineages) are distributed perpendicularly from the reef crest, perfectly aligned with wave energy. There are six clonal lineages with clones dispersed in at least two adjacent habitats that strongly demonstrate phenotypic plasticity. Eighty per cent of the colonies in these lineages are "sheet tree" on the upper slope, while 80%-100% are encrusting or massive on the mid slope and back reef. This is a unique example of phenotypic plasticity among reef-building coral clones as corals typically have wave-tolerant growth forms in high-energy reef areas. © 2017 John Wiley & Sons Ltd.

  11. Effects of ocean acidification and sea-level rise on coral reefs

    Science.gov (United States)

    Yates, K.K.; Moyer, R.P.

    2010-01-01

    U.S. Geological Survey (USGS) scientists are developing comprehensive records of historical and modern coral reef growth and calcification rates relative to changing seawater chemistry resulting from increasing atmospheric CO2 from the pre-industrial period to the present. These records will provide the scientific foundation for predicting future impacts of ocean acidification and sea-level rise on coral reef growth. Changes in coral growth rates in response to past changes in seawater pH are being examined by using cores from coral colonies.

  12. Growth

    Science.gov (United States)

    John R. Jones; George A. Schier

    1985-01-01

    This chapter considers aspen growth as a process, and discusses some characteristics of the growth and development of trees and stands. For the most part, factors affecting growth are discussed elsewhere, particularly in the GENETICS AND VARIATION chapter and in chapters in PART 11. ECOLOGY. Aspen growth as it relates to wood production is examined in the WOOD RESOURCE...

  13. Effects of ocean acidification on the dissolution rates of reef-coral skeletons

    Directory of Open Access Journals (Sweden)

    Robert van Woesik

    2013-11-01

    Full Text Available Ocean acidification threatens the foundation of tropical coral reefs. This study investigated three aspects of ocean acidification: (i the rates at which perforate and imperforate coral-colony skeletons passively dissolve when pH is 7.8, which is predicted to occur globally by 2100, (ii the rates of passive dissolution of corals with respect to coral-colony surface areas, and (iii the comparative rates of a vertical reef-growth model, incorporating passive dissolution rates, and predicted sea-level rise. By 2100, when the ocean pH is expected to be 7.8, perforate Montipora coral skeletons will lose on average 15 kg CaCO3 m−2 y−1, which is approximately −10.5 mm of vertical reduction of reef framework per year. This rate of passive dissolution is higher than the average rate of reef growth over the last several millennia and suggests that reefs composed of perforate Montipora coral skeletons will have trouble keeping up with sea-level rise under ocean acidification. Reefs composed of primarily imperforate coral skeletons will not likely dissolve as rapidly, but our model shows they will also have trouble keeping up with sea-level rise by 2050.

  14. Organic matter degradation drives benthic cyanobacterial mat abundance on Caribbean coral reefs.

    Science.gov (United States)

    Brocke, Hannah J; Polerecky, Lubos; de Beer, Dirk; Weber, Miriam; Claudet, Joachim; Nugues, Maggy M

    2015-01-01

    Benthic cyanobacterial mats (BCMs) are impacting coral reefs worldwide. However, the factors and mechanisms driving their proliferation are unclear. We conducted a multi-year survey around the Caribbean island of Curaçao, which revealed highest BCM abundance on sheltered reefs close to urbanised areas. Reefs with high BCM abundance were also characterised by high benthic cover of macroalgae and low cover of corals. Nutrient concentrations in the water-column were consistently low, but markedly increased just above substrata (both sandy and hard) covered with BCMs. This was true for sites with both high and low BCM coverage, suggesting that BCM growth is stimulated by a localised, substrate-linked release of nutrients from the microbial degradation of organic matter. This hypothesis was supported by a higher organic content in sediments on reefs with high BCM coverage, and by an in situ experiment which showed that BCMs grew within days on sediments enriched with organic matter (Spirulina). We propose that nutrient runoff from urbanised areas stimulates phototrophic blooms and enhances organic matter concentrations on the reef. This organic matter is transported by currents and settles on the seabed at sites with low hydrodynamics. Subsequently, nutrients released from the organic matter degradation fuel the growth of BCMs. Improved management of nutrients generated on land should lower organic loading of sediments and other benthos (e.g. turf and macroalgae) to reduce BCM proliferation on coral reefs.

  15. COLLABORATIVE GUIDE: A REEF MANAGER'S GUIDE TO ...

    Science.gov (United States)

    Innovative strategies to conserve the world's coral reefs are included in a new guide released today by NOAA, and the Australian Great Barrier Reef Marine Park Authority, with author contributions from a variety of international partners from government agencies, non-governmental organizations, and academic institutions. Referred to as A Reef Manager's Guide to Coral Bleaching, the guide will provide coral reef managers with the latest scientific information on the causes of coral bleaching and new management strategies for responding to this significant threat to coral reef ecosystems. Innovative strategies to conserve the world's coral reefs are included in a new guide released today by NOAA, and the Australian Great Barrier Reef Marine Park Authority, with author contributions from a variety of international partners from government agencies, non-governmental organizations, and academic institutions. Dr. Jordan West, of the National Center for Environmental Assessment, was a major contributor to the guide. Referred to as

  16. Accretion history of mid-Holocene coral reefs from the southeast Florida continental reef tract, USA

    Science.gov (United States)

    Stathakopoulos, A.; Riegl, B. M.

    2015-03-01

    Sixteen new coral reef cores were collected to better understand the accretion history and composition of submerged relict reefs offshore of continental southeast (SE) Florida. Coral radiometric ages from three sites on the shallow inner reef indicate accretion initiated by 8,050 Cal BP and terminated by 5,640 Cal BP. The reef accreted up to 3.75 m of vertical framework with accretion rates that averaged 2.53 m kyr-1. The reef was composed of a nearly even mixture of Acropora palmata and massive corals. In many cases, cores show an upward transition from massives to A. palmata and may indicate local dominance by this species prior to reef demise. Quantitative macroscopic analyses of reef clasts for various taphonomic and diagenetic features did not correlate well with depth/environmental-related trends established in other studies. The mixed coral framestone reef lacks a classical Caribbean reef zonation and is best described as an immature reef and/or a series of fused patch reefs; a pattern that is evident in both cores and reef morphology. This is in stark contrast to the older and deeper outer reef of the SE Florida continental reef tract. Accretion of the outer reef lasted from 10,695-8,000 Cal BP and resulted in a larger and better developed structure that achieved a distinct reef zonation. The discrepancies in overall reef morphology and size as well as the causes of reef terminations remain elusive without further study, yet they likely point to different climatic/environmental conditions during their respective accretion histories.

  17. Variability in the ecophysiology of Halimeda spp. (Chlorophyta, Bryopsidales) on Conch Reef, Florida Keys, USA

    NARCIS (Netherlands)

    Beach, K; Walters, L; Vroom, P; Coyer, J; Hunter, C

    The photosynthetic performance, pigmentation, and growth of a Halimeda community were studied over a depth gradient on Conch Reef, Florida Keys, USA during summer-fall periods of 5 consecutive years. The physiology and growth of H. tuna (Ellis & Solander) Lamouroux and H. opuntia (L.) Lamouroux on

  18. High macroalgal cover and low coral recruitment undermines the potential resilience of the world's southernmost coral reef assemblages

    KAUST Repository

    Hoey, Andrew; Pratchett, Morgan S.; Cvitanovic, Christopher

    2011-01-01

    Coral reefs are under increasing pressure from anthropogenic and climate-induced stressors. The ability of reefs to reassemble and regenerate after disturbances (i.e., resilience) is largely dependent on the capacity of herbivores to prevent macroalgal expansion, and the replenishment of coral populations through larval recruitment. Currently there is a paucity of this information for higher latitude, subtropical reefs. To assess the potential resilience of the benthic reef assemblages of Lord Howe Island (31°32?S, 159°04?E), the worlds' southernmost coral reef, we quantified the benthic composition, densities of juvenile corals (as a proxy for coral recruitment), and herbivorous fish communities. Despite some variation among habitats and sites, benthic communities were dominated by live scleractinian corals (mean cover 37.4%) and fleshy macroalgae (20.9%). Live coral cover was higher than in most other subtropical reefs and directly comparable to lower latitude tropical reefs. Juvenile coral densities (0.8 ind.m -2), however, were 5-200 times lower than those reported for tropical reefs. Overall, macroalgal cover was negatively related to the cover of live coral and the density of juvenile corals, but displayed no relationship with herbivorous fish biomass. The biomass of herbivorous fishes was relatively low (204 kg.ha -1), and in marked contrast to tropical reefs was dominated by macroalgal browsing species (84.1%) with relatively few grazing species. Despite their extremely low biomass, grazing fishes were positively related to both the density of juvenile corals and the cover of bare substrata, suggesting that they may enhance the recruitment of corals through the provision of suitable settlement sites. Although Lord Howe Islands' reefs are currently coral-dominated, the high macroalgal cover, coupled with limited coral recruitment and low coral growth rates suggest these reefs may be extremely susceptible to future disturbances. © 2011 Hoey et al.

  19. High macroalgal cover and low coral recruitment undermines the potential resilience of the world's southernmost coral reef assemblages

    KAUST Repository

    Hoey, Andrew

    2011-10-03

    Coral reefs are under increasing pressure from anthropogenic and climate-induced stressors. The ability of reefs to reassemble and regenerate after disturbances (i.e., resilience) is largely dependent on the capacity of herbivores to prevent macroalgal expansion, and the replenishment of coral populations through larval recruitment. Currently there is a paucity of this information for higher latitude, subtropical reefs. To assess the potential resilience of the benthic reef assemblages of Lord Howe Island (31°32?S, 159°04?E), the worlds\\' southernmost coral reef, we quantified the benthic composition, densities of juvenile corals (as a proxy for coral recruitment), and herbivorous fish communities. Despite some variation among habitats and sites, benthic communities were dominated by live scleractinian corals (mean cover 37.4%) and fleshy macroalgae (20.9%). Live coral cover was higher than in most other subtropical reefs and directly comparable to lower latitude tropical reefs. Juvenile coral densities (0.8 ind.m -2), however, were 5-200 times lower than those reported for tropical reefs. Overall, macroalgal cover was negatively related to the cover of live coral and the density of juvenile corals, but displayed no relationship with herbivorous fish biomass. The biomass of herbivorous fishes was relatively low (204 kg.ha -1), and in marked contrast to tropical reefs was dominated by macroalgal browsing species (84.1%) with relatively few grazing species. Despite their extremely low biomass, grazing fishes were positively related to both the density of juvenile corals and the cover of bare substrata, suggesting that they may enhance the recruitment of corals through the provision of suitable settlement sites. Although Lord Howe Islands\\' reefs are currently coral-dominated, the high macroalgal cover, coupled with limited coral recruitment and low coral growth rates suggest these reefs may be extremely susceptible to future disturbances. © 2011 Hoey et al.

  20. High macroalgal cover and low coral recruitment undermines the potential resilience of the world's southernmost coral reef assemblages.

    Directory of Open Access Journals (Sweden)

    Andrew S Hoey

    Full Text Available Coral reefs are under increasing pressure from anthropogenic and climate-induced stressors. The ability of reefs to reassemble and regenerate after disturbances (i.e., resilience is largely dependent on the capacity of herbivores to prevent macroalgal expansion, and the replenishment of coral populations through larval recruitment. Currently there is a paucity of this information for higher latitude, subtropical reefs. To assess the potential resilience of the benthic reef assemblages of Lord Howe Island (31°32'S, 159°04'E, the worlds' southernmost coral reef, we quantified the benthic composition, densities of juvenile corals (as a proxy for coral recruitment, and herbivorous fish communities. Despite some variation among habitats and sites, benthic communities were dominated by live scleractinian corals (mean cover 37.4% and fleshy macroalgae (20.9%. Live coral cover was higher than in most other subtropical reefs and directly comparable to lower latitude tropical reefs. Juvenile coral densities (0.8 ind.m(-2, however, were 5-200 times lower than those reported for tropical reefs. Overall, macroalgal cover was negatively related to the cover of live coral and the density of juvenile corals, but displayed no relationship with herbivorous fish biomass. The biomass of herbivorous fishes was relatively low (204 kg.ha(-1, and in marked contrast to tropical reefs was dominated by macroalgal browsing species (84.1% with relatively few grazing species. Despite their extremely low biomass, grazing fishes were positively related to both the density of juvenile corals and the cover of bare substrata, suggesting that they may enhance the recruitment of corals through the provision of suitable settlement sites. Although Lord Howe Islands' reefs are currently coral-dominated, the high macroalgal cover, coupled with limited coral recruitment and low coral growth rates suggest these reefs may be extremely susceptible to future disturbances.

  1. Acropora palmata reef framework: A reliable indicator of sea level in the western atlantic for the past 10,000 years

    Science.gov (United States)

    Lighty, R. G.; MacIntyre, I. G.; Stuckenrath, R.

    1982-10-01

    A minimum sea-level curve for the past 10,000 years has been constructed on the basis of radiocarbon dates of Acropora palmata (Lamarck) samples from the shallow-water framework of both relict and modern reefs of the tropical western Atlantic. A. palmata framework is a reliable reference for reconstructing the history of late Quaternary sea levels owing to its restricted depth range (palmata framework, the ease of obtaining uncontaminated samples, and the minimal compaction of A. palmata reef facies. The minimum sea-level curve constructed in this study is useful not only in evaluating the reliability of present and future Holocene sea-level curves for the western Atlantic, but also in estimating paleo-water depths in the study of Holocene reef history of this area.

  2. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    International Nuclear Information System (INIS)

    Yudovin-Farber, Ira; Beyth, Nurit; Weiss, Ervin I.; Domb, Abraham J.

    2010-01-01

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  3. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yudovin-Farber, Ira [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel); Beyth, Nurit; Weiss, Ervin I. [Hebrew University of Jerusalem, Department of Prosthodontics, Faculty of Dentistry (Israel); Domb, Abraham J., E-mail: avid@ekmd.huji.ac.i [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel)

    2010-02-15

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  4. Coral reef surveys in India

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.

    and in persuading the Government agencies to take protective and conservational measures. The current approach is towards establishing a monitoring design to detect changes in reef ecology in the long-term, and to standardize the survey techniques to be compatible...

  5. Quantifying Coral Reef Ecosystem Services

    Science.gov (United States)

    Coral reefs have been declining during the last four decades as a result of both local and global anthropogenic stresses. Numerous research efforts to elucidate the nature, causes, magnitude, and potential remedies for the decline have led to the widely held belief that the recov...

  6. Reversal of ocean acidification enhances net coral reef calcification.

    Science.gov (United States)

    Albright, Rebecca; Caldeira, Lilian; Hosfelt, Jessica; Kwiatkowski, Lester; Maclaren, Jana K; Mason, Benjamin M; Nebuchina, Yana; Ninokawa, Aaron; Pongratz, Julia; Ricke, Katharine L; Rivlin, Tanya; Schneider, Kenneth; Sesboüé, Marine; Shamberger, Kathryn; Silverman, Jacob; Wolfe, Kennedy; Zhu, Kai; Caldeira, Ken

    2016-03-17

    Approximately one-quarter of the anthropogenic carbon dioxide released into the atmosphere each year is absorbed by the global oceans, causing measurable declines in surface ocean pH, carbonate ion concentration ([CO3(2-)]), and saturation state of carbonate minerals (Ω). This process, referred to as ocean acidification, represents a major threat to marine ecosystems, in particular marine calcifiers such as oysters, crabs, and corals. Laboratory and field studies have shown that calcification rates of many organisms decrease with declining pH, [CO3(2-)], and Ω. Coral reefs are widely regarded as one of the most vulnerable marine ecosystems to ocean acidification, in part because the very architecture of the ecosystem is reliant on carbonate-secreting organisms. Acidification-induced reductions in calcification are projected to shift coral reefs from a state of net accretion to one of net dissolution this century. While retrospective studies show large-scale declines in coral, and community, calcification over recent decades, determining the contribution of ocean acidification to these changes is difficult, if not impossible, owing to the confounding effects of other environmental factors such as temperature. Here we quantify the net calcification response of a coral reef flat to alkalinity enrichment, and show that, when ocean chemistry is restored closer to pre-industrial conditions, net community calcification increases. In providing results from the first seawater chemistry manipulation experiment of a natural coral reef community, we provide evidence that net community calcification is depressed compared with values expected for pre-industrial conditions, indicating that ocean acidification may already be impairing coral reef growth.

  7. Disease outbreaks, bleaching and a cyclone drive changes in coral assemblages on an inshore reef of the Great Barrier Reef

    Science.gov (United States)

    Haapkylä, J.; Melbourne-Thomas, J.; Flavell, M.; Willis, B. L.

    2013-09-01

    Coral disease is a major threat to the resilience of coral reefs; thus, understanding linkages between disease outbreaks and disturbances predicted to increase with climate change is becoming increasingly important. Coral disease surveys conducted twice yearly between 2008 and 2011 at a turbid inshore reef in the central Great Barrier Reef spanned two disturbance events, a coral bleaching event in 2009 and a severe cyclone (cyclone `Yasi') in 2011. Surveys of coral cover, community structure and disease prevalence throughout this 4-yr study provide a unique opportunity to explore cumulative impacts of disturbance events and disease for inshore coral assemblages. The principal coral disease at the study site was atramentous necrosis (AtN), and it primarily affected the key inshore, reef-building coral Montipora aequituberculata. Other diseases detected were growth anomalies, white syndrome and brown band syndrome. Diseases affected eight coral genera, although Montipora was, by far, the genus mostly affected. The prevalence of AtN followed a clear seasonal pattern, with disease outbreaks occurring only in wet seasons. Mean prevalence of AtN on Montipora spp. (63.8 % ± 3.03) was three- to tenfold greater in the wet season of 2009, which coincided with the 2009 bleaching event, than in other years. Persistent wet season outbreaks of AtN combined with the impacts of bleaching and cyclone events resulted in a 50-80 % proportional decline in total coral cover. The greatest losses of branching and tabular acroporids occurred following the low-salinity-induced bleaching event of 2009, and the greatest losses of laminar montiporids occurred following AtN outbreaks in 2009 and in 2011 following cyclone Yasi. The shift to a less diverse coral assemblage and the concomitant loss of structural complexity are likely to have long-term consequences for associated vertebrate and invertebrate communities on Magnetic Island reefs.

  8. Is proximity to land-based sources of coral stressors an appropriate measure of risk to coral reefs? An example from the Florida Reef Tract.

    Science.gov (United States)

    Lirman, Diego; Fong, Peggy

    2007-06-01

    Localized declines in coral condition are commonly linked to land-based sources of stressors that influence gradients of water quality, and the distance to sources of stressors is commonly used as a proxy for predicting the vulnerability and future status of reef resources. In this study, we evaluated explicitly whether proximity to shore and connections to coastal bays, two measures of potential land-based sources of disturbance, influence coral community and population structure, and the abundance, distribution, and condition of corals within patch reefs of the Florida Reef Tract. In the Florida Keys, long-term monitoring has documented significant differences in water quality along a cross-shelf gradient. Inshore habitats exhibit higher levels of nutrients (DIN and TP), TOC, turbidity, and light attenuation, and these levels decrease with increasing distance from shore and connections to tidal bays. In clear contrast to these patterns of water quality, corals on inshore patch reefs exhibited significantly higher coral cover, higher growth rates, and lower partial mortality rates than those documented in similar offshore habitats. Coral recruitment rates did not differ between inshore and offshore habitats. Corals on patch reefs closest to shore had well-spread population structures numerically dominated by intermediate to large colonies, while offshore populations showed narrower size-distributions that become increasingly positively skewed. Differences in size-structure of coral populations were attributed to faster growth and lower rates of partial mortality at inshore habitats. While the underlying causes for the favorable condition of inshore coral communities are not yet known, we hypothesize that the ability of corals to shift their trophic mode under adverse environmental conditions may be partly responsible for the observed patterns, as shown in other reef systems. This study, based on data collected from a uniform reef habitat type and coral species

  9. Radiocarbon dating for the Quaternary scientist

    International Nuclear Information System (INIS)

    Pilcher, J.R.

    1991-01-01

    The accuracy of many conventional and accelerator mass spectrometry (AMS) radiocarbon dates is not adequate for the sort of questions now being asked in Quaternary studies. The need for, and effects of, radiocarbon calibration are discussed and guide-lines offered for the selection of a laboratory. High precision laboratories and the use of wiggle matching will go a long way to answering the critical questions of rates of change and durations of events in the Holocene. (Author)

  10. Coral reef carbonate budgets and ecological drivers in the naturally high temperature and high alkalinity environment of the Red Sea

    KAUST Repository

    Roik, Anna Krystyna

    2017-10-17

    The coral structural framework is crucial for maintaining reef ecosystem function and services. In the central Red Sea, a naturally high alkalinity is beneficial to reef growth, but rising water temperatures impair the calcification capacity of reef-building organisms. However, it is currently unknown how beneficial and detrimental factors affect the balance between calcification and erosion, and thereby the overall growth of the reef framework. To provide insight into present-day carbonate budgets and reef growth dynamics in the central Red Sea, we measured in situ net-accretion and net-erosion rates (Gnet) by deployment of limestone blocks and estimated census-based carbonate budgets (Gbudget) in four reef sites along a cross-shelf gradient (25 km). We assessed abiotic variables (i.e., temperature, inorganic nutrients, and carbonate system variables) and biotic drivers (i.e., calcifier and bioeroder abundances). On average, total alkalinity AT (2346-2431 μmol kg-1), aragonite saturation state (4.5-5.2 Ωa), and pCO2 (283-315 μatm) were close to estimates of pre-industrial global ocean surface waters. Despite these calcification-favorable carbonate system conditions, Gnet and Gbudget encompassed positive (offshore) and negative net-production (midshore-lagoon and exposed nearshore site) estimates. Notably, Gbudget maxima were lower compared to reef growth from pristine Indian Ocean sites. Yet, a comparison with historical data from the northern Red Sea suggests that overall reef growth in the Red Sea has likely remained similar since 1995. When assessing sites across the shelf gradient, AT correlated well with reef growth rates (ρ = 0.89), while temperature was a weaker, negative correlate (ρ = -0.71). Further, AT explained about 65% of Gbudget in a best fitting distance-based linear model. Interestingly, parrotfish abundances added up to 82% of explained variation, further substantiating recent studies highlighting the importance of parrotfish to reef

  11. Coral reef carbonate budgets and ecological drivers in the naturally high temperature and high alkalinity environment of the Red Sea

    KAUST Repository

    Roik, Anna Krystyna; Rö thig, Till; Pogoreutz, Claudia; Voolstra, Christian R.

    2017-01-01

    The coral structural framework is crucial for maintaining reef ecosystem function and services. In the central Red Sea, a naturally high alkalinity is beneficial to reef growth, but rising water temperatures impair the calcification capacity of reef-building organisms. However, it is currently unknown how beneficial and detrimental factors affect the balance between calcification and erosion, and thereby the overall growth of the reef framework. To provide insight into present-day carbonate budgets and reef growth dynamics in the central Red Sea, we measured in situ net-accretion and net-erosion rates (Gnet) by deployment of limestone blocks and estimated census-based carbonate budgets (Gbudget) in four reef sites along a cross-shelf gradient (25 km). We assessed abiotic variables (i.e., temperature, inorganic nutrients, and carbonate system variables) and biotic drivers (i.e., calcifier and bioeroder abundances). On average, total alkalinity AT (2346-2431 μmol kg-1), aragonite saturation state (4.5-5.2 Ωa), and pCO2 (283-315 μatm) were close to estimates of pre-industrial global ocean surface waters. Despite these calcification-favorable carbonate system conditions, Gnet and Gbudget encompassed positive (offshore) and negative net-production (midshore-lagoon and exposed nearshore site) estimates. Notably, Gbudget maxima were lower compared to reef growth from pristine Indian Ocean sites. Yet, a comparison with historical data from the northern Red Sea suggests that overall reef growth in the Red Sea has likely remained similar since 1995. When assessing sites across the shelf gradient, AT correlated well with reef growth rates (ρ = 0.89), while temperature was a weaker, negative correlate (ρ = -0.71). Further, AT explained about 65% of Gbudget in a best fitting distance-based linear model. Interestingly, parrotfish abundances added up to 82% of explained variation, further substantiating recent studies highlighting the importance of parrotfish to reef

  12. Coral Reef and Hardbottom from Unified Florida Reef Tract Map (NODC Accession 0123059)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a subset of the Unified Map representing Coral reef and Hardbottom areas. Version 1.1 - December 2013. The Unified Florida Reef Tract Map (Unified...

  13. Is Quaternary geology ready for the future?

    Science.gov (United States)

    Ritter, Dale F.

    1996-07-01

    Armed with a better understanding of process and an array of developing dating techniques, Quaternary geology is poised to achieve greater recognition in the general scientific community. This recognition however, will require some thought adjustment. Quaternary geologists will have to convince government, industry and a variety of scientific groups that they possess unique training and expertise that is needed as part of the thrust to fully understand and/or resolve major scientific problems. Therefore, future research and education efforts should not focus on developing a rigidly defined identity within geoscience, but instead should seek ways to be integrated with interdisciplinary teams that will investigate complex environmental and climate change problems. Such a scenaria creates and enermous dilemma for Quaternary geologists because they will derive greater intellectual stimulation from scientists working in discplines other than geology, and their scientific collaboratiors will most likely not be their academic colleagues. This outward expansion of our scientific network will require the development of interdsciplinary research collaboration and/or degree-granting programs at the graduate level. To accomplish such goals, universities must resist "turf protection", and funding agencies muts become more efficient at facilitating interdisciplinary research.

  14. DNA Barcoding through Quaternary LDPC Codes.

    Science.gov (United States)

    Tapia, Elizabeth; Spetale, Flavio; Krsticevic, Flavia; Angelone, Laura; Bulacio, Pilar

    2015-01-01

    For many parallel applications of Next-Generation Sequencing (NGS) technologies short barcodes able to accurately multiplex a large number of samples are demanded. To address these competitive requirements, the use of error-correcting codes is advised. Current barcoding systems are mostly built from short random error-correcting codes, a feature that strongly limits their multiplexing accuracy and experimental scalability. To overcome these problems on sequencing systems impaired by mismatch errors, the alternative use of binary BCH and pseudo-quaternary Hamming codes has been proposed. However, these codes either fail to provide a fine-scale with regard to size of barcodes (BCH) or have intrinsic poor error correcting abilities (Hamming). Here, the design of barcodes from shortened binary BCH codes and quaternary Low Density Parity Check (LDPC) codes is introduced. Simulation results show that although accurate barcoding systems of high multiplexing capacity can be obtained with any of these codes, using quaternary LDPC codes may be particularly advantageous due to the lower rates of read losses and undetected sample misidentification errors. Even at mismatch error rates of 10(-2) per base, 24-nt LDPC barcodes can be used to multiplex roughly 2000 samples with a sample misidentification error rate in the order of 10(-9) at the expense of a rate of read losses just in the order of 10(-6).

  15. DNA Barcoding through Quaternary LDPC Codes.

    Directory of Open Access Journals (Sweden)

    Elizabeth Tapia

    Full Text Available For many parallel applications of Next-Generation Sequencing (NGS technologies short barcodes able to accurately multiplex a large number of samples are demanded. To address these competitive requirements, the use of error-correcting codes is advised. Current barcoding systems are mostly built from short random error-correcting codes, a feature that strongly limits their multiplexing accuracy and experimental scalability. To overcome these problems on sequencing systems impaired by mismatch errors, the alternative use of binary BCH and pseudo-quaternary Hamming codes has been proposed. However, these codes either fail to provide a fine-scale with regard to size of barcodes (BCH or have intrinsic poor error correcting abilities (Hamming. Here, the design of barcodes from shortened binary BCH codes and quaternary Low Density Parity Check (LDPC codes is introduced. Simulation results show that although accurate barcoding systems of high multiplexing capacity can be obtained with any of these codes, using quaternary LDPC codes may be particularly advantageous due to the lower rates of read losses and undetected sample misidentification errors. Even at mismatch error rates of 10(-2 per base, 24-nt LDPC barcodes can be used to multiplex roughly 2000 samples with a sample misidentification error rate in the order of 10(-9 at the expense of a rate of read losses just in the order of 10(-6.

  16. Sponge communities on Caribbean coral reefs are structured by factors that are top-down, not bottom-up.

    Science.gov (United States)

    Pawlik, Joseph R; Loh, Tse-Lynn; McMurray, Steven E; Finelli, Christopher M

    2013-01-01

    Caribbean coral reefs have been transformed in the past few decades with the demise of reef-building corals, and sponges are now the dominant habitat-forming organisms on most reefs. Competing hypotheses propose that sponge communities are controlled primarily by predatory fishes (top-down) or by the availability of picoplankton to suspension-feeding sponges (bottom-up). We tested these hypotheses on Conch Reef, off Key Largo, Florida, by placing sponges inside and outside predator-excluding cages at sites with less and more planktonic food availability (15 m vs. 30 m depth). There was no evidence of a bottom-up effect on the growth of any of 5 sponge species, and 2 of 5 species grew more when caged at the shallow site with lower food abundance. There was, however, a strong effect of predation by fishes on sponge species that lacked chemical defenses. Sponges with chemical defenses grew slower than undefended species, demonstrating a resource trade-off between growth and the production of secondary metabolites. Surveys of the benthic community on Conch Reef similarly did not support a bottom-up effect, with higher sponge cover at the shallower depth. We conclude that the structure of sponge communities on Caribbean coral reefs is primarily top-down, and predict that removal of sponge predators by overfishing will shift communities toward faster-growing, undefended species that better compete for space with threatened reef-building corals.

  17. Sponge communities on Caribbean coral reefs are structured by factors that are top-down, not bottom-up.

    Directory of Open Access Journals (Sweden)

    Joseph R Pawlik

    Full Text Available Caribbean coral reefs have been transformed in the past few decades with the demise of reef-building corals, and sponges are now the dominant habitat-forming organisms on most reefs. Competing hypotheses propose that sponge communities are controlled primarily by predatory fishes (top-down or by the availability of picoplankton to suspension-feeding sponges (bottom-up. We tested these hypotheses on Conch Reef, off Key Largo, Florida, by placing sponges inside and outside predator-excluding cages at sites with less and more planktonic food availability (15 m vs. 30 m depth. There was no evidence of a bottom-up effect on the growth of any of 5 sponge species, and 2 of 5 species grew more when caged at the shallow site with lower food abundance. There was, however, a strong effect of predation by fishes on sponge species that lacked chemical defenses. Sponges with chemical defenses grew slower than undefended species, demonstrating a resource trade-off between growth and the production of secondary metabolites. Surveys of the benthic community on Conch Reef similarly did not support a bottom-up effect, with higher sponge cover at the shallower depth. We conclude that the structure of sponge communities on Caribbean coral reefs is primarily top-down, and predict that removal of sponge predators by overfishing will shift communities toward faster-growing, undefended species that better compete for space with threatened reef-building corals.

  18. Sea-level standstill and dominant hermatypic coral from the holocene raised reef terraces at the Kikai Island, Ryukyu Islands

    International Nuclear Information System (INIS)

    Hongo, Chuki

    2010-01-01

    Coral reef terraces are one of the best recorders of biological response to environmental change events (e.g., sea-level changes). Kikai Island provides a rare opportunity to show biological and ecological frameworks (e.g., competition, coexistence, and succession) during a recent geological period. The island is fringed by raised Holocene raised reef terraces, which formed as a result of periodic tectonic uplifts. This study aims to characterize the spatial and temporal changes of corals at this island during the Holocene. The analysis is based on topographical and biological data obtained for the three sites (Shidooke, Kadon, and Nakugama reefs). Three raised reef terraces (Terrace II, III, and IV) grew from 7300 to 4500 years ago (during 2800 years), from 4500 to 2900 years ago (during 1600 years), and from 2900 to 1800 years ago (during 1100 years), respectively. Terrace II and III were uplifted 1-2 m around 4500 years ago and around 2900 years ago. Terrace IV was uplifted 1-2 m around 1800 years ago. The modern reef has been composed of corals for 1800 years. Sixteen coral genera and 53 species were recorded from the reef terraces. Terrace III and IV were dominated by four coral species (A. digitifera, A. robusta, G. retiformis, and F. stelligera), but Terrace II was predominantly composed of A. digitifera and A. robusta. These biological and ecological variations between the terraces represent a growth strategy responding to differences of reef growth time and/or insolation. (author)

  19. separation of strontium and cesium from ternary and quaternary lithium chloride-potassium chloride salts via melt crystallization

    Directory of Open Access Journals (Sweden)

    Ammon N. Williams

    2015-12-01

    Full Text Available Separation of cesium chloride (CsCl and strontium chloride (SrCl2 from the lithium chloride-potassium chloride (LiCl-KCl salt was studied using a melt crystallization process similar to the reverse vertical Bridgeman growth technique. A ternary SrCl2-LiCl-KCl salt was explored at similar growth rates (1.8–5 mm/h and compared with CsCl ternary results to identify similarities. Quaternary experiments were also conducted and compared with the ternary cases to identify trends and possible limitations to the separations process. In the ternary case, as much as 68% of the total salt could be recycled per batch process. In the quaternary experiments, separation of Cs and Sr was nearly identical at the slower rates; however, as the growth rate increased, SrCl2 separated more easily than CsCl. The quaternary results show less separation and rate dependence than in both ternary cases. As an estimated result, only 51% of the total salt could be recycled per batch. Furthermore, two models have been explored to further understand the growth process and separation. A comparison of the experimental and modeling results reveals that the nonmixed model fits reasonably well with the ternary and quaternary data sets. A dimensional analysis was performed and a correlation was identified to semipredict the segregation coefficient.

  20. Separation of strontium and cesium from ternary and quaternary lithium chloride-potassium chloride salts via melt crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Ammon n.; Pack, Michael [Dept. of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond (United States); Phongikaroon, Spathorn [Dept. of Chemical and Materials Engineering and Nuclear Engineering Program, University of Idaho, Idaho Falls (United States)

    2015-12-15

    Separation of cesium chloride (CsCl) and strontium chloride (SrCl{sub 2}) from the lithium chloride-potassium chloride (LiCl-KCl) salt was studied using a melt crystallization process similar to the reverse vertical Bridgeman growth technique. A ternary SrCl2-LiCl-KCl salt was explored at similar growth rates (1.8-5 mm/h) and compared with CsCl ternary results to identify similarities. Quaternary experiments were also conducted and compared with the ternary cases to identify trends and possible limitations to the separations process. In the ternary case, as much as 68% of the total salt could be recycled per batch process. In the quaternary experiments, separation of Cs and Sr was nearly identical at the slower rates; however, as the growth rate increased, SrCl{sub 2} separated more easily than CsCl. The quaternary results show less separation and rate dependence than in both ternary cases. As an estimated result, only 51% of the total salt could be recycled per batch. Furthermore, two models have been explored to further understand the growth process and separation. A comparison of the experimental and modeling results reveals that the nonmixed model fits reasonably well with the ternary and quaternary data sets. A dimensional analysis was performed and a correlation was identified to semipredict the segregation coefficient.

  1. Artificial Reef Effect in relation to Offshore Renewable Energy Conversion: State of the Art

    Directory of Open Access Journals (Sweden)

    Olivia Langhamer

    2012-01-01

    Full Text Available The rapid worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization, thus acting as artificial reefs. The artificial reef effect is important when constructing, for example, scour protections since it can generate an enhanced habitat. Specifically, artificial structures can create increased heterogeneity in the area important for species diversity and density. Offshore energy installations also have the positive side effect as they are a sanctuary area for trawled organisms. Higher survival of fish and bigger fish is an expected outcome that can contribute to a spillover to outer areas. One negative side effect is that invasive species can find new habitats in artificial reefs and thus influence the native habitats and their associated environment negatively. Different scour protections in offshore wind farms can create new habitats compensating for habitat loss by offshore energy installations. These created habitats differ from the lost habitat in species composition substantially. A positive reef effect is dependent on the nature and the location of the reef and the characteristics of the native populations. An increase in surface area of scour protections by using specially designed material can also support the reef effect and its productivity.

  2. Assessing threats from coral and crustose coralline algae disease on the reefs of New Caledonia

    Science.gov (United States)

    Aeby, Greta S.; Tribollet, Aline; Lasne, Gregory; Work, Thierry M.

    2015-01-01

    The present study reports the results of the first quantitative survey of lesions on coral and crustose coralline algae (CCA) on reefs in the lagoon of New Caledonia. Surveys on inshore and offshore reefs were conducted at 13 sites in 2010, with 12 sites resurveyed in 2013. Thirty coral diseases affecting 15 coral genera were found, with low overall disease prevalence (<1%). This study extends the known distribution of growth anomalies to the coral genera Platygyraand Hydnophora, endolithic hypermycosis to Platygyra, Leptoria and Goniastrea and extends the geographic range of three CCA diseases. We found the first trematode infection in Porites outside of Hawaii. Disease prevalence differed among coral genera, with Porites having more lesions, and Acropora and Montipora fewer lesions, than expected on the basis of field abundance. Inshore reefs had a lower coral-colony density, species diversity and reduced CCA cover than did the offshore reefs. Disease prevalence was significantly higher on inshore reefs in 2013 than in 2010, but did not change on offshore reefs. The potential ecological impact of individual coral diseases was assessed using an integrative-scoring and relative-ranking scheme based on average frequency of occurrence, prevalence and estimated degree of virulence. The top-five ranked diseases were all tissue-loss diseases.

  3. 27 years of benthic and coral community dynamics on turbid, highly urbanised reefs off Singapore.

    Science.gov (United States)

    Guest, J R; Tun, K; Low, J; Vergés, A; Marzinelli, E M; Campbell, A H; Bauman, A G; Feary, D A; Chou, L M; Steinberg, P D

    2016-11-08

    Coral cover on reefs is declining globally due to coastal development, overfishing and climate change. Reefs isolated from direct human influence can recover from natural acute disturbances, but little is known about long term recovery of reefs experiencing chronic human disturbances. Here we investigate responses to acute bleaching disturbances on turbid reefs off Singapore, at two depths over a period of 27 years. Coral cover declined and there were marked changes in coral and benthic community structure during the first decade of monitoring at both depths. At shallower reef crest sites (3-4 m), benthic community structure recovered towards pre-disturbance states within a decade. In contrast, there was a net decline in coral cover and continuing shifts in community structure at deeper reef slope sites (6-7 m). There was no evidence of phase shifts to macroalgal dominance but coral habitats at deeper sites were replaced by unstable substrata such as fine sediments and rubble. The persistence of coral dominance at chronically disturbed shallow sites is likely due to an abundance of coral taxa which are tolerant to environmental stress. In addition, high turbidity may interact antagonistically with other disturbances to reduce the impact of thermal stress and limit macroalgal growth rates.

  4. Evaluating the human impact on groundwater quality discharging into a coastal reef lagoon

    Science.gov (United States)

    Rebolledo-Vieyra, M.; Hernandez-Terrones, L.; Soto, M.; Lecossec, A.; Monroy-Rios, E.

    2008-12-01

    The Eastern coast of the Yucatan Peninsula has the fastest growth rate in Mexico and groundwater is the only source of drinking water in the region. The consequences of the lack of proper infrastructure to collect and treat wastewater and the impact of human activities on the quality of groundwater are addressed. The groundwater in the coastal aquifer of Quintana Roo (SE Mexico) discharges directly into the ocean. In addition, the coral reef of the Eastern Yucatan Peninsula is part of the Mesoamerican Coral Reef System, one of the largest in the world. The interaction of the reef-lagoon hydraulics with the coastal aquifer of Puerto Morelos (NE Yucatan Peninsula), and a major input of NH4, SO4, SiO2, as a consequence of the use of septic tanks and the lack of modern wastewater treatment plants are presented. No seasonal parameters differences were observed, suggesting that groundwater composition reaching the reef lagoon is not changing seasonally. A conceptual model of the coastal aquifer was developed, in order to explain how the human activities are impacting directly on the groundwater quality that, potentially, will have a direct impact on the coral reef. The protection and conservation of coral reefs must be directly related with a policy of sound management of coastal aquifers and wastewater treatment.

  5. Coral skeletons provide historical evidence of phosphorus runoff on the great barrier reef.

    Directory of Open Access Journals (Sweden)

    Jennie Mallela

    Full Text Available Recently, the inshore reefs of the Great Barrier Reef have declined rapidly because of deteriorating water quality. Increased catchment runoff is one potential culprit. The impacts of land-use on coral growth and reef health however are largely circumstantial due to limited long-term data on water quality and reef health. Here we use a 60 year coral core record to show that phosphorus contained in the skeletons (P/Ca of long-lived, near-shore Porites corals on the Great Barrier Reef correlates with annual records of fertiliser application and particulate phosphorus loads in the adjacent catchment. Skeletal P/Ca also correlates with Ba/Ca, a proxy for fluvial sediment loading, again linking near-shore phosphorus records with river runoff. Coral core records suggest that phosphorus levels increased 8 fold between 1949 and 2008 with the greatest levels coinciding with periods of high fertiliser-phosphorus use. Periods of high P/Ca correspond with intense agricultural activity and increased fertiliser application in the river catchment following agricultural expansion and replanting after cyclone damage. Our results demonstrate how coral P/Ca records can be used to assess terrestrial nutrient loading of vulnerable near-shore reefs.

  6. Population Structure of Montastraea cavernosa on Shallow versus Mesophotic Reefs in Bermuda

    Science.gov (United States)

    Goodbody-Gringley, Gretchen; Marchini, Chiara; Chequer, Alex D.; Goffredo, Stefano

    2015-01-01

    Mesophotic coral reef ecosystems remain largely unexplored with only limited information available on taxonomic composition, abundance and distribution. Yet, mesophotic reefs may serve as potential refugia for shallow-water species and thus understanding biodiversity, ecology and connectivity of deep reef communities is integral for resource management and conservation. The Caribbean coral, Montastraea cavernosa, is considered a depth generalist and is commonly found at mesophotic depths. We surveyed abundance and size-frequency of M. cavernosa populations at six shallow (10m) and six upper mesophotic (45m) sites in Bermuda and found population structure was depth dependent. The mean surface area of colonies at mesophotic sites was significantly smaller than at shallow sites, suggesting that growth rates and maximum colony surface area are limited on mesophotic reefs. Colony density was significantly higher at mesophotic sites, however, resulting in equal contributions to overall percent cover. Size-frequency distributions between shallow and mesophotic sites were also significantly different with populations at mesophotic reefs skewed towards smaller individuals. Overall, the results of this study provide valuable baseline data on population structure, which indicate that the mesophotic reefs of Bermuda support an established population of M. cavernosa. PMID:26544963

  7. ReefLink Database: A decision support tool for Linking Coral Reefs and Society Through Systems Thinking

    Science.gov (United States)

    Coral reefs provide the ecological foundation for productive and diverse fish and invertebrate communities that support multibillion dollar reef fishing and tourism industries. Yet reefs are threatened by growing coastal development, climate change, and over-exploitation. A key i...

  8. Satellite remote sensing reveals a positive impact of living oyster reefs on microalgal biofilm development

    Directory of Open Access Journals (Sweden)

    C. Echappé

    2018-02-01

    Full Text Available Satellite remote sensing (RS is routinely used for the large-scale monitoring of microphytobenthos (MPB biomass in intertidal mudflats and has greatly improved our knowledge of MPB spatio-temporal variability and its potential drivers. Processes operating on smaller scales however, such as the impact of benthic macrofauna on MPB development, to date remain underinvestigated. In this study, we analysed the influence of wild Crassostrea gigas oyster reefs on MPB biofilm development using multispectral RS. A 30-year time series (1985–2015 combining high-resolution (30 m Landsat and SPOT data was built in order to explore the relationship between C. gigas reefs and MPB spatial distribution and seasonal dynamics, using the normalized difference vegetation index (NDVI. Emphasis was placed on the analysis of a before–after control-impact (BACI experiment designed to assess the effect of oyster killing on the surrounding MPB biofilms. Our RS data reveal that the presence of oyster reefs positively affects MPB biofilm development. Analysis of the historical time series first showed the presence of persistent, highly concentrated MPB patches around oyster reefs. This observation was supported by the BACI experiment which showed that killing the oysters (while leaving the physical reef structure, i.e. oyster shells, intact negatively affected both MPB biofilm biomass and spatial stability around the reef. As such, our results are consistent with the hypothesis of nutrient input as an explanation for the MPB growth-promoting effect of oysters, whereby organic and inorganic matter released through oyster excretion and biodeposition stimulates MPB biomass accumulation. MPB also showed marked seasonal variations in biomass and patch shape, size and degree of aggregation around the oyster reefs. Seasonal variations in biomass, with higher NDVI during spring and autumn, were consistent with those observed on broader scales in other European mudflats. Our

  9. Satellite remote sensing reveals a positive impact of living oyster reefs on microalgal biofilm development

    Science.gov (United States)

    Echappé, Caroline; Gernez, Pierre; Méléder, Vona; Jesus, Bruno; Cognie, Bruno; Decottignies, Priscilla; Sabbe, Koen; Barillé, Laurent

    2018-02-01

    Satellite remote sensing (RS) is routinely used for the large-scale monitoring of microphytobenthos (MPB) biomass in intertidal mudflats and has greatly improved our knowledge of MPB spatio-temporal variability and its potential drivers. Processes operating on smaller scales however, such as the impact of benthic macrofauna on MPB development, to date remain underinvestigated. In this study, we analysed the influence of wild Crassostrea gigas oyster reefs on MPB biofilm development using multispectral RS. A 30-year time series (1985-2015) combining high-resolution (30 m) Landsat and SPOT data was built in order to explore the relationship between C. gigas reefs and MPB spatial distribution and seasonal dynamics, using the normalized difference vegetation index (NDVI). Emphasis was placed on the analysis of a before-after control-impact (BACI) experiment designed to assess the effect of oyster killing on the surrounding MPB biofilms. Our RS data reveal that the presence of oyster reefs positively affects MPB biofilm development. Analysis of the historical time series first showed the presence of persistent, highly concentrated MPB patches around oyster reefs. This observation was supported by the BACI experiment which showed that killing the oysters (while leaving the physical reef structure, i.e. oyster shells, intact) negatively affected both MPB biofilm biomass and spatial stability around the reef. As such, our results are consistent with the hypothesis of nutrient input as an explanation for the MPB growth-promoting effect of oysters, whereby organic and inorganic matter released through oyster excretion and biodeposition stimulates MPB biomass accumulation. MPB also showed marked seasonal variations in biomass and patch shape, size and degree of aggregation around the oyster reefs. Seasonal variations in biomass, with higher NDVI during spring and autumn, were consistent with those observed on broader scales in other European mudflats. Our study provides the

  10. Drought Increases Consumer Pressure on Oyster Reefs in Florida, USA.

    Directory of Open Access Journals (Sweden)

    Hanna G Garland

    Full Text Available Coastal economies and ecosystems have historically depended on oyster reefs, but this habitat has declined globally by 85% because of anthropogenic activities. In a Florida estuary, we investigated the cause of newly reported losses of oysters. We found that the oyster reefs have deteriorated from north to south and that this deterioration was positively correlated with the abundance of carnivorous conchs and water salinity. In experiments across these gradients, oysters survived regardless of salinity if conchs were excluded. After determining that conchs were the proximal cause of oyster loss, we tested whether elevated water salinity was linked to conch abundance either by increasing conch growth and survivorship or by decreasing the abundance of a predator of conchs. In field experiments across a salinity gradient, we failed to detect spatial variation in predation on conchs or in conch growth and survivorship. A laboratory experiment, however, demonstrated the role of salinity by showing that conch larvae failed to survive at low salinities. Because this estuary's salinity increased in 2006 in response to reduced inputs of freshwater, we concluded that the ultimate cause of oyster decline was an increase in salinity. According to records from 2002 to 2012, oyster harvests have remained steady in the northernmost estuaries of this ecoregion (characterized by high reef biomass, low salinity, and low conch abundance but have declined in the southernmost estuaries (characterized by lower reef biomass, increases in salinity, and increases in conch abundance. Oyster conservation in this ecoregion, which is probably one of the few that still support viable oyster populations, may be undermined by drought-induced increases in salinity causing an increased abundance of carnivorous conchs.

  11. Drought Increases Consumer Pressure on Oyster Reefs in Florida, USA.

    Science.gov (United States)

    Garland, Hanna G; Kimbro, David L

    2015-01-01

    Coastal economies and ecosystems have historically depended on oyster reefs, but this habitat has declined globally by 85% because of anthropogenic activities. In a Florida estuary, we investigated the cause of newly reported losses of oysters. We found that the oyster reefs have deteriorated from north to south and that this deterioration was positively correlated with the abundance of carnivorous conchs and water salinity. In experiments across these gradients, oysters survived regardless of salinity if conchs were excluded. After determining that conchs were the proximal cause of oyster loss, we tested whether elevated water salinity was linked to conch abundance either by increasing conch growth and survivorship or by decreasing the abundance of a predator of conchs. In field experiments across a salinity gradient, we failed to detect spatial variation in predation on conchs or in conch growth and survivorship. A laboratory experiment, however, demonstrated the role of salinity by showing that conch larvae failed to survive at low salinities. Because this estuary's salinity increased in 2006 in response to reduced inputs of freshwater, we concluded that the ultimate cause of oyster decline was an increase in salinity. According to records from 2002 to 2012, oyster harvests have remained steady in the northernmost estuaries of this ecoregion (characterized by high reef biomass, low salinity, and low conch abundance) but have declined in the southernmost estuaries (characterized by lower reef biomass, increases in salinity, and increases in conch abundance). Oyster conservation in this ecoregion, which is probably one of the few that still support viable oyster populations, may be undermined by drought-induced increases in salinity causing an increased abundance of carnivorous conchs.

  12. Millennial-scale ocean acidification and late Quaternary

    Energy Technology Data Exchange (ETDEWEB)

    Riding, Dr Robert E [University of Tennessee (UT); Liang, Liyuan [ORNL; Braga, Dr Juan Carlos [Universidad de Granada, Departamento de Estratigrafıa y Paleontologıa, Granada, Spain

    2014-01-01

    Ocean acidification by atmospheric carbon dioxide has increased almost continuously since the last glacial maximum (LGM), 21 000 years ago. It is expected to impair tropical reef development, but effects on reefs at the present day and in the recent past have proved difficult to evaluate. We present evidence that acidification has already significantly reduced the formation of calcified bacterial crusts in tropical reefs. Unlike major reef builders such as coralline algae and corals that more closely control their calcification, bacterial calcification is very sensitive to ambient changes in carbonate chemistry. Bacterial crusts in reef cavities have declined in thickness over the past 14 000 years with largest reduction occurring 12 000 10 000 years ago. We interpret this as an early effect of deglacial ocean acidification on reef calcification and infer that similar crusts were likely to have been thicker when seawater carbonate saturation was increased during earlier glacial intervals, and thinner during interglacials. These changes in crust thickness could have substantially affected reef development over glacial cycles, as rigid crusts significantly strengthen framework and their reduction would have increased the susceptibility of reefs to biological and physical erosion. Bacterial crust decline reveals previously unrecognized millennial-scale acidification effects on tropical reefs. This directs attention to the role of crusts in reef formation and the ability of bioinduced calcification to reflect changes in seawater chemistry. It also provides a long-term context for assessing anticipated anthropogenic effects.

  13. Artificial reefs: “Attraction versus Production”

    Directory of Open Access Journals (Sweden)

    Eduardo Barros Fagundes Netto

    2011-04-01

    Full Text Available The production of fish is the most common reason for the construction and installation of an artificial reef. More recently, environmental concerns and conservation of biological resources have been instrumental to the formulation of new goals of the research. One of the issues to be resolved is the biological function of “attraction vs. production” as a result of the use of artificial reefs. The uncertainty as to the answer to the question whether the artificial reefs will or not benefit the development of fish stocks could be solved if the artificial reefs would be managed as marine protected areas.

  14. Cyanobacteria in Coral Reef Ecosystems: A Review

    Directory of Open Access Journals (Sweden)

    L. Charpy

    2012-01-01

    Full Text Available Cyanobacteria have dominated marine environments and have been reef builders on Earth for more than three million years (myr. Cyanobacteria still play an essential role in modern coral reef ecosystems by forming a major component of epiphytic, epilithic, and endolithic communities as well as of microbial mats. Cyanobacteria are grazed by reef organisms and also provide nitrogen to the coral reef ecosystems through nitrogen fixation. Recently, new unicellular cyanobacteria that express nitrogenase were found in the open ocean and in coral reef lagoons. Furthermore, cyanobacteria are important in calcification and decalcification. All limestone surfaces have a layer of boring algae in which cyanobacteria often play a dominant role. Cyanobacterial symbioses are abundant in coral reefs; the most common hosts are sponges and ascidians. Cyanobacteria use tactics beyond space occupation to inhibit coral recruitment. Cyanobacteria can also form pathogenic microbial consortia in association with other microbes on living coral tissues, causing coral tissue lysis and death, and considerable declines in coral reefs. In deep lagoons, coccoid cyanobacteria are abundant and are grazed by ciliates, heteroflagellates, and the benthic coral reef community. Cyanobacteria produce metabolites that act as attractants for some species and deterrents for some grazers of the reef communities.

  15. Vaal Reefs South uranium plant

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    The Vaal Reefs mining complex, part of the Anglo American Corporation, is the largest gold and uranium producing complex in the world, being South Africa's principal producer, accounting for about a quarter of the country's uranium production. Vaal Reefs South uranium plant in the Orkney district was recently officially opened by Dr AJA Roux, the retiring president of the Atomic Energy Board and chairman of the Uranium Enrichment Corporation and will increase the country's uranium production. In the field of technology, and particularly processing technology, South Africa has shown the world unprecedented technology achievement in the field of uranium extraction from low grade ores and the development of the unique uranium enrichment process. New technical innovations that have been incorporated in this new plant are discussed

  16. Implementation Strategy for Coral Reef Transplantation Methods in Support of Natural Resource Planning, Management and NEPANESDI Project Number 491

    Science.gov (United States)

    2016-05-01

    Branching N/A Spawners Vera Cruz, Mexico Reef lagoon, shallow, limited wave action, with donor colony nearby. Fixed nursery made of PVC and PET...0 growth, due to being wiped out by asymmetric predation. N/A Smith et al., 2007 Pocillopora eydouxi Branching Zooxanthella e genotypes...Referenc e Pavona cactus Small domed colonies composed of thin, undulating plates N/A Spawners Guam, Marianas Islands Cetti Bay, Site B, reef

  17. Topographical features of physiographic unit borders on reef flat in fringing reefs

    OpenAIRE

    Nakai, Tatsuo

    2007-01-01

    In coral reef ecosystem spatial structure of 10^1-10^3m scale provide very important aspect in coral reef conservation. Nakai (2007) showed that physiographic unit (PGU) could be set as well as zonation on reef flat of fringing reef. The borders of PGUs delimiting it from the open sea or an adjacent PGU are constituted by landforms such as reef crest or channels. In this article the landforms becoming the borders of PGUs were discussed and the PGU property was clarified.

  18. Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook

    Science.gov (United States)

    Baker, Andrew C.; Glynn, Peter W.; Riegl, Bernhard

    2008-12-01

    regenerating and recovering coral reefs have originated from broadcast spawning taxa with a potential for asexual growth, relatively long distance dispersal, successful settlement, rapid growth and a capacity for framework construction. Whether or not affected reefs can continue to function as before will depend on: (1) how much coral cover is lost, and which species are locally extirpated; (2) the ability of remnant and recovering coral communities to adapt or acclimatize to higher temperatures and other climatic factors such as reductions in aragonite saturation state; (3) the changing balance between reef accumulation and bioerosion; and (4) our ability to maintain ecosystem resilience by restoring healthy levels of herbivory, macroalgal cover, and coral recruitment. Bleaching disturbances are likely to become a chronic stress in many reef areas in the coming decades, and coral communities, if they cannot recover quickly enough, are likely to be reduced to their most hardy or adaptable constituents. Some degraded reefs may already be approaching this ecological asymptote, although to date there have not been any global extinctions of individual coral species as a result of bleaching events. Since human populations inhabiting tropical coastal areas derive great value from coral reefs, the degradation of these ecosystems as a result of coral bleaching and its associated impacts is of considerable societal, as well as biological concern. Coral reef conservation strategies now recognize climate change as a principal threat, and are engaged in efforts to allocate conservation activity according to geographic-, taxonomic-, and habitat-specific priorities to maximize coral reef survival. Efforts to forecast and monitor bleaching, involving both remote sensed observations and coupled ocean-atmosphere climate models, are also underway. In addition to these efforts, attempts to minimize and mitigate bleaching impacts on reefs are immediately required. If significant reductions in

  19. Density-dependent habitat selection and performance by a large mobile reef fish.

    Science.gov (United States)

    Lindberg, William J; Frazer, Thomas K; Portier, Kenneth M; Vose, Frederic; Loftin, James; Murie, Debra J; Mason, Doran M; Nagy, Brian; Hart, Mary K

    2006-04-01

    Many exploited reef fish are vulnerable to overfishing because they concentrate over hard-bottom patchy habitats. How mobile reef fish use patchy habitat, and the potential consequences on demographic parameters, must be known for spatially explicit population dynamics modeling, for discriminating essential fish habitat (EFH), and for effectively planning conservation measures (e.g., marine protected areas, stock enhancement, and artificial reefs). Gag, Mycteroperca microlepis, is an ecologically and economically important warm-temperate grouper in the southeastern United States, with behavioral and life history traits conducive to large-scale field experiments. The Suwannee Regional Reef System (SRRS) was built of standard habitat units (SHUs) in 1991-1993 to manipulate and control habitat patchiness and intrinsic habitat quality, and thereby test predictions from habitat selection theory. Colonization of the SRRS by gag over the first six years showed significant interactions of SHU size, spacing, and reef age; with trajectories modeled using a quadratic function for closely spaced SHUs (25 m) and a linear model for widely spaced SHUs (225 m), with larger SHUs (16 standardized cubes) accumulating significantly more gag faster than smaller 4-cube SHUs (mean = 72.5 gag/16-cube SHU at 225-m spacing by year 6, compared to 24.2 gag/4-cube SHU for same spacing and reef age). Residency times (mean = 9.8 mo), indicative of choice and measured by ultrasonic telemetry (1995-1998), showed significant interaction of SHU size and spacing consistent with colonization trajectories. Average relative weight (W(r)) and incremental growth were greater on smaller than larger SHUs (mean W(r) = 104.2 vs. 97.7; incremental growth differed by 15%), contrary to patterns of abundance and residency. Experimental manipulation of shelter on a subset of SRRS sites (2000-2001) confirmed our hypothesis that shelter limits local densities of gag, which, in turn, regulates their growth and

  20. Ecological States and the Resilience of Coral Reefs

    Directory of Open Access Journals (Sweden)

    Tim McClanahan

    2002-12-01

    Full Text Available We review the evidence for multiple ecological states and the factors that create ecological resilience in coral reef ecosystems. There are natural differences among benthic communities along gradients of water temperature, light, nutrients, and organic matter associated with upwelling-downwelling and onshore-offshore systems. Along gradients from oligotrophy to eutrophy, plant-animal symbioses tend to decrease, and the abundance of algae and heterotrophic suspension feeders and the ratio of organic to inorganic carbon production tend to increase. Human influences such as fishing, increased organic matter and nutrients, sediments, warm water, and transportation of xenobiotics and diseases are common causes of a large number of recently reported ecological shifts. It is often the interaction of persistent and multiple synergistic disturbances that causes permanent ecological transitions, rather than the succession of individual short-term disturbances. For example, fishing can remove top-level predators, resulting in the ecological release of prey such as sea urchins and coral-eating invertebrates. When sea urchins are not common because of unsuitable habitat, recruitment limitations, and diseases, and when overfishing removes herbivorous fish, frondose brown algae can dominate. Terrigenous sediments carried onto reefs as a result of increased soil erosion largely promote the dominance of turf or articulated green algae. Elevated nutrients and organic matter can increase internal eroders of reef substratum and a mixture of filamentous algae. Local conservation actions that attempt to reduce fishing and terrestrial influences promote the high production of inorganic carbon that is necessary for reef growth. However, global climate change threatens to undermine such actions because of increased bleaching and mortality caused by warm-water anomalies, weakened coral skeletons caused by reduced aragonite availability in reef waters, and increased

  1. Mapping Oyster Reef Habitats in Mobile Bay

    Science.gov (United States)

    Bolte, Danielle

    2011-01-01

    Oyster reefs around the world are declining rapidly, and although they haven t received as much attention as coral reefs, they are just as important to their local ecosystems and economies. Oyster reefs provide habitats for many species of fish, invertebrates, and crustaceans, as well as the next generations of oysters. Oysters are also harvested from many of these reefs and are an important segment of many local economies, including that of Mobile Bay, where oysters rank in the top five commercial marine species both by landed weight and by dollar value. Although the remaining Mobile Bay oyster reefs are some of the least degraded in the world, projected climate change could have dramatic effects on the health of these important ecosystems. The viability of oyster reefs depends on water depth and temperature, appropriate pH and salinity levels, and the amount of dissolved oxygen in the water. Projected increases in sea level, changes in precipitation and runoff patterns, and changes in pH resulting from increases in the amount of carbon dioxide dissolved in the oceans could all affect the viability of oyster reefs in the future. Human activities such as dredging and unsustainable harvesting practices are also adversely impacting the oyster reefs. Fortunately, several projects are already under way to help rebuild or support existing or previously existing oyster reefs. The success of these projects will depend on the local effects of climate change on the current and potential habitats and man s ability to recognize and halt unsustainable harvesting practices. As the extent and health of the reefs changes, it will have impacts on the Mobile Bay ecosystem and economy, changing the resources available to the people who live there and to the rest of the country, since Mobile Bay is an important national source of seafood. This project identified potential climate change impacts on the oyster reefs of Mobile Bay, including the possible addition of newly viable

  2. Uranium-series dating of Quaternary deposits

    International Nuclear Information System (INIS)

    Schwarcz, H.; Gascoyne, M.

    1984-01-01

    In view of the interest in the problem of time scales in geomorphology it is fortunate that there exists a number of geochronometers applicable to the measurement of the age of such young deposits. This paper is specifically devoted to those which arise from the disequilibrium between the daughter isotopes of U-238 and U-235, and their respective parents. The authors describe applications to Quaternary continental deposits that can give information about climatic change (travertine, lacrustine limestones, pedogenic carbonates, detrinal sediments, volcanic rocks). (Auth.)

  3. Coral Reef Community Composition in the Context of Disturbance History on the Great Barrier Reef, Australia

    Science.gov (United States)

    Graham, Nicholas A. J.; Chong-Seng, Karen M.; Huchery, Cindy; Januchowski-Hartley, Fraser A.; Nash, Kirsty L.

    2014-01-01

    Much research on coral reefs has documented differential declines in coral and associated organisms. In order to contextualise this general degradation, research on community composition is necessary in the context of varied disturbance histories and the biological processes and physical features thought to retard or promote recovery. We conducted a spatial assessment of coral reef communities across five reefs of the central Great Barrier Reef, Australia, with known disturbance histories, and assessed patterns of coral cover and community composition related to a range of other variables thought to be important for reef dynamics. Two of the reefs had not been extensively disturbed for at least 15 years prior to the surveys. Three of the reefs had been severely impacted by crown-of-thorns starfish outbreaks and coral bleaching approximately a decade before the surveys, from which only one of them was showing signs of recovery based on independent surveys. We incorporated wave exposure (sheltered and exposed) and reef zone (slope, crest and flat) into our design, providing a comprehensive assessment of the spatial patterns in community composition on these reefs. Categorising corals into life history groupings, we document major coral community differences in the unrecovered reefs, compared to the composition and covers found on the undisturbed reefs. The recovered reef, despite having similar coral cover, had a different community composition from the undisturbed reefs, which may indicate slow successional processes, or a different natural community dominance pattern due to hydrology and other oceanographic factors. The variables that best correlated with patterns in the coral community among sites included the density of juvenile corals, herbivore fish biomass, fish species richness and the cover of macroalgae. Given increasing impacts to the Great Barrier Reef, efforts to mitigate local stressors will be imperative to encouraging coral communities to persist into

  4. Say what? Coral reef sounds as indicators of community assemblages and reef conditions

    Science.gov (United States)

    Mooney, T. A.; Kaplan, M. B.

    2016-02-01

    Coral reefs host some of the highest diversity of life on the planet. Unfortunately, reef health and biodiversity is declining or is threatened as a result of climate change and human influences. Tracking these changes is necessary for effective resource management, yet estimating marine biodiversity and tracking trends in ecosystem health is a challenging and expensive task, especially in many pristine reefs which are remote and difficult to access. Many fishes, mammals and invertebrates make sound. These sounds are reflective of a number of vital biological processes and are a cue for settling reef larvae. Biological sounds may be a means to quantify ecosystem health and biodiversity, however the relationship between coral reef soundscapes and the actual taxa present remains largely unknown. This study presents a comparative evaluation of the soundscape of multiple reefs, naturally differing in benthic cover and fish diversity, in the U.S. Virgin Islands National Park. Using multiple recorders per reef we characterized spacio-temporal variation in biological sound production within and among reefs. Analyses of sounds recorded over 4 summer months indicated diel trends in both fish and snapping shrimp acoustic frequency bands with crepuscular peaks at all reefs. There were small but statistically significant acoustic differences among sites on a given reef raising the possibility of potentially localized acoustic habitats. The strength of diel trends in lower, fish-frequency bands were correlated with coral cover and fish density, yet no such relationship was found with shrimp sounds suggesting that fish sounds may be of higher relevance to tracking certain coral reef conditions. These findings indicate that, in spite of considerable variability within reef soundscapes, diel trends in low-frequency sound production reflect reef community assemblages. Further, monitoring soundscapes may be an efficient means of establishing and monitoring reef conditions.

  5. Responses of reef building corals to microplastic exposure.

    Science.gov (United States)

    Reichert, Jessica; Schellenberg, Johannes; Schubert, Patrick; Wilke, Thomas

    2018-06-01

    Pollution of marine environments with microplastic particles (i.e. plastic fragments terrestrial origin, coastal ecosystems such as coral reefs are particularly threatened. Recent studies revealed that microplastic ingestion can have adverse effects on marine invertebrates. However, little is known about its effects on small-polyp stony corals that are the main framework builders in coral reefs. The goal of this study is to characterise how different coral species I) respond to microplastic particles and whether the exposure might II) lead to health effects. Therefore, six small-polyp stony coral species belonging to the genera Acropora, Pocillopora, and Porites were exposed to microplastics (polyethylene, size 37-163 μm, concentration ca. 4000 particles L -1 ) over four weeks, and responses and effects on health were documented. The study showed that the corals responded differentially to microplastics. Cleaning mechanisms (direct interaction, mucus production) but also feeding interactions (i.e. interaction with mesenterial filaments, ingestion, and egestion) were observed. Additionally, passive contact through overgrowth was documented. In five of the six studied species, negative effects on health (i.e. bleaching and tissue necrosis) were reported. We here provide preliminary knowledge about coral-microplastic-interactions. The results call for further investigations of the effects of realistic microplastic concentrations on growth, reproduction, and survival of stony corals. This might lead to a better understanding of resilience capacities in coral reef ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Marketing places: multipurpose artificial reefs as tourist attraction proposal

    Directory of Open Access Journals (Sweden)

    Marco Antonio Moraes Ocke

    2013-11-01

    Full Text Available Marketing places focuses on the use of marketing activities as a way to leverage the socioeconomic development of cities, states and countries and in this context, the attractions of a given locality are essential to the growth of tourism in the region. From the literature review of concepts and types of attractions, this paper aims to suggest the convergence of the concepts of natural attraction and artificial attraction applied to artificial multipurpose artificial reefs and describe its hybrid nature to recover degraded areas by coastal erosion, increased marine biodiversity and the ability to improve the quality of waves for surfing, resulting in an increase of tourist flow of the region. Through the observation of cases in countries that have invested in the implementation of multipurpose artificial reefs it has been found positive results regarding tourism development and socioeconomic in these regions and thus, this paper considers the possibility of deployment of multipurpose artificial reefs along the Brazilian coast as a proposal to attract visitors and promote benefits to the receiving place.

  7. Project O.R.B (Operation Reef Ball): Creating Artificial Reefs, Educating the Community

    Science.gov (United States)

    Phipps, A.

    2012-04-01

    The Project O.R.B. (Operation Reef Ball) team at South Plantation High School's Everglades Restoration & Environmental Science Magnet Program is trying to help our ailing south Florida coral reefs by constructing, deploying, and monitoring designed artificial reefs. Students partnered with the Reef Ball Foundation, local concrete companies, state parks, Girl Scouts, Sea Scouts, local universities and environmental agencies to construct concrete reef balls, each weighing approximately 500 lbs (227 kg). Students then deployed two artificial reefs consisting of over 30 concrete reef balls in two sites previously permitted for artificial reef deployment. One artificial reef was placed approximately 1.5 miles (2.4 km) offshore of Golden Beach in Miami-Dade County with the assistance of Florida Atlantic University and their research vessel. A twin reef was deployed at the mouth of the river in Oleta River State Park in Miami. Monitoring and maintenance of the sites is ongoing with semi-annual reports due to the Reef Ball Foundation and DERM (Department of Environmental Resource Management) of Miami-Dade County. A second goal of Project O.R.B. is aligned with the Florida Local Action Strategy, the Southeast Florida Coral Reef Initiative, and the U.S. Coral Reef Task Force, all of which point out the importance of awareness and education as key components to the health of our coral reefs. Project O.R.B. team members developed and published an activity book targeting elementary school students. Outreach events incorporate cascade learning where high school students teach elementary and middle school students about various aspects of coral reefs through interactive "edu-tainment" modules. Attendees learn about water sampling, salinity, beach erosion, surface runoff, water cycle, ocean zones, anatomy of coral, human impact on corals, and characteristics of a well-designed artificial reef. Middle school students snorkel on the artificial reef to witness first-hand the success

  8. Benthic communities at two remote Pacific coral reefs: effects of reef habitat, depth, and wave energy gradients on spatial patterns

    Directory of Open Access Journals (Sweden)

    Gareth J. Williams

    2013-05-01

    Full Text Available Kingman Reef and Palmyra Atoll in the central Pacific are among the most remote coral reefs on the planet. Here we describe spatial patterns in their benthic communities across reef habitats and depths, and consider these in the context of oceanographic gradients. Benthic communities at both locations were dominated by calcifying organisms (54–86% cover, namely hard corals (20–74% and crustose coralline algae (CCA (10–36%. While turf algae were relatively common at both locations (8–22%, larger fleshy macroalgae were virtually absent at Kingman (<1% and rare at Palmyra (0.7–9.3%. Hard coral cover was higher, but with low diversity, in more sheltered habitats such as Palmyra’s backreef and Kingman’s patch reefs. Almost exclusive dominance by slow-growing Porites on Kingman’s patch reefs provides indirect evidence of competitive exclusion, probably late in a successional sequence. In contrast, the more exposed forereef habitats at both Kingman and Palmyra had higher coral diversity and were characterized by fast-growing corals (e.g., Acropora and Pocillopora, indicative of more dynamic environments. In general at both locations, soft coral cover increased with depth, likely reflecting increasingly efficient heterotrophic abilities. CCA and fleshy macroalgae cover decreased with depth, likely due to reduced light. Cover of other calcified macroalgae, predominantly Halimeda, increased with depth. This likely reflects the ability of many calcifying macroalgae to efficiently harvest light at deeper depths, in combination with an increased nutrient supply from upwelling promoting growth. At Palmyra, patterns of hard coral cover with depth were inconsistent, but cover peaked at mid-depths at Kingman. On Kingman’s forereef, benthic community composition was strongly related to wave energy, with hard coral cover decreasing and becoming more spatially clustered with increased wave energy, likely as a result of physical damage leading to

  9. Impacts of Artificial Reefs and Diving Tourism

    Directory of Open Access Journals (Sweden)

    Sandra Jakšić

    2013-10-01

    Full Text Available Coral reefs are currently endangered throughout the world. One of the main activities responsible for this is scuba-diving. Scuba-diving on coral reefs was not problematic in the begging, but due to popularization of the new sport, more and more tourists desired to participate in the activity. Mass tourism, direct contact of the tourists with the coral reefs and unprofessional behavior underwater has a negative effect on the coral reefs. The conflict between nature preservation and economy benefits related to scuba-diving tourism resulted in the creation of artificial reefs, used both to promote marine life and as tourists attractions, thereby taking the pressure off the natural coral reefs. Ships, vehicles and other large structures can be found on the coastal sea floor in North America, Australia, Japan and Europe. The concept of artificial reefs as a scuba-diving attraction was developed in Florida. The main goal was to promote aquaculture, with the popularization of scuba-diving attractions being a secondary effect. The aim of this paper is to determine the effects of artificial reefs on scuba-diving tourism, while taking into account the questionnaire carried out among 18 divers

  10. Parasite infestation increases on coral reefs without cleaner fish

    Science.gov (United States)

    Grutter, A. S.; De Brauwer, M.; Bshary, R.; Cheney, K. L.; Cribb, T. H.; Madin, E. M. P.; McClure, E. C.; Meekan, M. G.; Sun, D.; Warner, R. R.; Werminghausen, J.; Sikkel, P. C.

    2018-03-01

    Mutualisms are pivotal in shaping ecological communities. Iconic images of cleaner fish entering the mouths of predatory fish clients to remove ectoparasites epitomize their mutual benefit. Experimental manipulations of cleaner wrasse reveal declines in fish size and growth, and population abundance and diversity of client fishes in the absence of cleaner wrasse. Fishes grow more slowly and are less abundant and diverse on reefs without cleaner wrasse, both for larger species that are regularly cleaned and have high ectoparasite loads ("attractive species"), and for those smaller species that are rarely cleaned and are rarely infested with parasites ("unattractive species"). We therefore considered whether these previously observed declines in individual and population parameters on reefs without cleaners were related to increased ectoparasite infestation using an attractive species ( Hemigymnus melapterus, Labridae) and an unattractive species ( Pomacentrus amboinensis, Pomacentridae). Traps with these fish as a form of bait were deployed to sample blood-sucking gnathiid ectoparasites (Gnathiidae: Isopoda) on reefs from which cleaners ( Labroides dimidiatus, Labridae) have been removed for 13 yr. Cleaner fish could not enter traps to access the clients/hosts, but gnathiids could enter the traps to infest hosts; thus, this method sampled the indirect effect of cleaners on gnathiid infestation of fish. Infestation was higher on reefs without cleaners than on those with them. The effect was only detected during the daytime when cleaners are active and only on the attractive species ( H. melapterus). Thus, cleaner presence indirectly reduced fish exposure to parasites in a species that is highly susceptible to parasites, but not in one that is rarely infested with parasites. This suggests that cleaner presence indirectly reduces exposure of a common fish species to harmful parasites, which may explain some observed benefits in fishes at this location.

  11. Insights Into Nitrogen Isotope Fractionation in Coral Reefs

    Science.gov (United States)

    Lamb, K. A.; Swart, P. K.; Ellis, G. S.

    2002-12-01

    Environmental integrity in the Florida Reef tract and the Caribbean has been the center of concern for the past 15-20 years. Both the recreational and scientific communities alike have noticed an overall decline in coral reef health. This decline has manifested itself in the form of increased fleshy macroalgae growth and reduced coral cover, and in some cases, wide-scale coral mortality. Given the increasing dependence on a tourism-oriented economy in both South Florida and the Caribbean, much attention has been focused on maintaining reef longevity. A high nutrient load is believed to be the leading cause of degradation in the predominantly oligotrophic environment. Various studies have cited increased run off and input of anthropogenic wastes as the origin of these nutrients. It has also been suggested that the stable isotopes of nitrogen may provide a tracer with which to recognize the impact of anthropogenic nutrients within the coral reefs ecosystem. However, in utilizing both nitrogen and carbon stable isotopic methods on samples of particulate organic matter (POM) taken over the last three years, we find little evidence of the input of anthropogenic waste. δ15N values of POM fluctuate between +1 and +9 per mille, but usually remain in the +4 to +6 per mille range. Additionally, δ13C values are even more consistent, maintaining a balance between -19 to -21 per mille. These data are consistent with natural open-ocean values for δ15N and δ13C, indicating a lack of intense and prolonged exposure to anthropogenic wastes in the Florida Keys.

  12. Ningaloo Reef: Shallow Marine Habitats Mapped Using a Hyperspectral Sensor

    Science.gov (United States)

    Kobryn, Halina T.; Wouters, Kristin; Beckley, Lynnath E.; Heege, Thomas

    2013-01-01

    Research, monitoring and management of large marine protected areas require detailed and up-to-date habitat maps. Ningaloo Marine Park (including the Muiron Islands) in north-western Australia (stretching across three degrees of latitude) was mapped to 20 m depth using HyMap airborne hyperspectral imagery (125 bands) at 3.5 m resolution across the 762 km2 of reef environment between the shoreline and reef slope. The imagery was corrected for atmospheric, air-water interface and water column influences to retrieve bottom reflectance and bathymetry using the physics-based Modular Inversion and Processing System. Using field-validated, image-derived spectra from a representative range of cover types, the classification combined a semi-automated, pixel-based approach with fuzzy logic and derivative techniques. Five thematic classification levels for benthic cover (with probability maps) were generated with varying degrees of detail, ranging from a basic one with three classes (biotic, abiotic and mixed) to the most detailed with 46 classes. The latter consisted of all abiotic and biotic seabed components and hard coral growth forms in dominant or mixed states. The overall accuracy of mapping for the most detailed maps was 70% for the highest classification level. Macro-algal communities formed most of the benthic cover, while hard and soft corals represented only about 7% of the mapped area (58.6 km2). Dense tabulate coral was the largest coral mosaic type (37% of all corals) and the rest of the corals were a mix of tabulate, digitate, massive and soft corals. Our results show that for this shallow, fringing reef environment situated in the arid tropics, hyperspectral remote sensing techniques can offer an efficient and cost-effective approach to mapping and monitoring reef habitats over large, remote and inaccessible areas. PMID:23922921

  13. Coral Reef Response to Marine Isotope Stage (MIS) 5e Sea Level Changes in the Granitic Seychelles

    Science.gov (United States)

    Vyverberg, K.; Dechnik, B.; Dutton, A.; Webster, J.; Zwartz, D.

    2015-12-01

    Sea-level position has a direct control on coral reef morphology and composition. Examining changes in these parameters in fossil reefs can inform reconstructions of past sea-level behavior and, indirectly, ice sheet dynamics. Here we provide a detailed examination of fossil reefs from Marine Isotope Stage (MIS) 5e. These fossil reefs are located in the granitic Seychelles, which is tectonically stable site and far-field from the former margins of Northern Hemisphere ice sheets. To reconstruct relative sea level (RSL), we combine RTK and Total Station elevation surveys with sedimentary and taxonomic evaluations of eight fossil reef sites. Carbonate coralgal reef buildups of the shallowest portion of the reef are preserved in limestone outcrops that are protected by granite boulder overhangs. Two primary outcrop morphologies were observed at these sites: plastering and massive. Plastering outcrops manifest as thin (~ 1 m height x 1 m width x 0.5 m depth) vertical successions of reef framework and detritus, while massive outcrops are larger (~ 2-6 m height x 2-6 m width x 1-2 m depth). The base of these limestone outcrops consistently record a period of reef growth, characterized by corals or coralline algae colonizing the surface or face of a granite boulder and building upwards. This lower reefal unit is capped by a disconformity that is commonly overlain by coral rubble or a ~10 cm thick layer of micrite. Rubble units contain coarse fragments of the coralgal reef buildups while micrite layers consist of a relatively homogeneous fine-grained carbonate, bearing coral-dwelling, Pyrgomatid barnacles. In many of the outcrops, this succession is repeated upsection with another unit of coralgal reef framework capped by a disconformity that is recognized by the sharp transition to coral rubble or micrite with barnacles. We identified four distinct fossil coralgal assemblages in the limestone outcrops. These assemblages are consistent with modern assemblages which

  14. QUATERNARY HISTORY OF CEDRUS IN SOUTHERN EUROPE

    Directory of Open Access Journals (Sweden)

    D. Magri

    2012-05-01

    Full Text Available A database of 68 pollen records of Pleistocene age was compiled from the western Mediterranean regions, with the aim of reconstructing the history of Cedrus in south Europe during the last 2 Ma. Marine pollen records from the Alboran Sea suggest that Cedrus was present in Morocco throughout the Quaternary, while it was absent from the Iberian peninsula, except a possible local presence in a coastal site of southern Spain. In France, Cedrus pollen was recorded in Pliocene deposits, but its Quaternary finds are always very sparse and suggest a long distance origin of cedar pollen. Cedrus was widespread in all the Italian sites during the Early Pleistocene, but it is sporadically found in the Middle Pleistocene deposits. Although times and modes of the disappearance of Cedrus from Italy are not known, it appears that the marked climate changes occurred between 0.9 and 0.7 Ma determined its local extinction. A similar trend is found in Greece, where Cedrus may have persisted a little longer than in the Italian Peninsula. On the whole, the history of Cedrus in southern Europe indicates that it is a taxon vulnerable to global climate changes and warns of a future risk of extinction also in the rest of the Mediterranean Basin.

  15. Late Quaternary climate change shapes island biodiversity.

    Science.gov (United States)

    Weigelt, Patrick; Steinbauer, Manuel Jonas; Cabral, Juliano Sarmento; Kreft, Holger

    2016-04-07

    Island biogeographical models consider islands either as geologically static with biodiversity resulting from ecologically neutral immigration-extinction dynamics, or as geologically dynamic with biodiversity resulting from immigration-speciation-extinction dynamics influenced by changes in island characteristics over millions of years. Present climate and spatial arrangement of islands, however, are rather exceptional compared to most of the Late Quaternary, which is characterized by recurrent cooler and drier glacial periods. These climatic oscillations over short geological timescales strongly affected sea levels and caused massive changes in island area, isolation and connectivity, orders of magnitude faster than the geological processes of island formation, subsidence and erosion considered in island theory. Consequences of these oscillations for present biodiversity remain unassessed. Here we analyse the effects of present and Last Glacial Maximum (LGM) island area, isolation, elevation and climate on key components of angiosperm diversity on islands worldwide. We find that post-LGM changes in island characteristics, especially in area, have left a strong imprint on present diversity of endemic species. Specifically, the number and proportion of endemic species today is significantly higher on islands that were larger during the LGM. Native species richness, in turn, is mostly determined by present island characteristics. We conclude that an appreciation of Late Quaternary environmental change is essential to understand patterns of island endemism and its underlying evolutionary dynamics.

  16. Quaternary magnetic excursions recorded in marine sediments.

    Science.gov (United States)

    Channell, J. E. T.

    2017-12-01

    This year is the golden (50th) anniversary of the first documentation of a magnetic excursion, the Laschamp excursion in volcanics from the Chaine des Puys (Bonhommet and Babkine, 1967). The first recording of an excursion in sediments was from the Blake Outer Ridge (Smith and Foster, 1969). Magnetic excursions are directional aberrations of the geomagnetic field apparently involving short-lived reversal of the main dipole field. They have durations of a few kyrs, and are therefore rarely recorded in sediments with mean sedimentation rates Palma), and 670 ka (Osaka Bay), implying at least 11 excursions in the Brunhes Chron. For the Matuyama Chron, excursions have been recorded in marine sediments at 868 ka (Kamikatsura?), 932 ka (Santa Rosa), 1051 ka (Intra-Jaramillo), 1115 ka (Punaruu), 1255 ka (Bjorn), 1476 ka (Gardar), 1580 ka (Gilsa), and 2737 ka (Porcupine). Excursions coincide with minima in relative paleointensity (RPI) records. Ages are from correlation of excursion records to oxygen isotope records in the same cores, and ice-volume calibration of the oxygen isotope template. The marine sediment record of excursions, combined with independent documentation of excursions in lavas with Ar/Ar age control, is progressively strengthening our knowledge of the excursion inventory in the Quaternary, and enhancing the importance of excursions and RPI in Quaternary stratigraphy.

  17. A Global Estimate of the Number of Coral Reef Fishers.

    Directory of Open Access Journals (Sweden)

    Louise S L Teh

    Full Text Available Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world's small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale.

  18. A Global Estimate of the Number of Coral Reef Fishers.

    Science.gov (United States)

    Teh, Louise S L; Teh, Lydia C L; Sumaila, U Rashid

    2013-01-01

    Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world's small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale.

  19. 75 FR 48934 - Coral Reef Conservation Program Implementation Guidelines

    Science.gov (United States)

    2010-08-12

    ...-01] RIN 0648-ZC19 Coral Reef Conservation Program Implementation Guidelines AGENCY: National Oceanic... Guidelines (Guidelines) for the Coral Reef Conservation Program (CRCP or Program) under the Coral Reef... assistance for coral reef conservation projects under the Act. NOAA revised the Implementation Guidelines for...

  20. Status and review of health of Indian coral reefs

    Digital Repository Service at National Institute of Oceanography (India)

    Rajan, R.; Satyanarayan, C.; Raghunathan, C.; Koya, S.S.; Ravindran, J.; Manikandan, B.; Venkataraman, K.

    Status of reef health incorporating species-wise cover of scleractinians has been reported covering 61 stations in 29 reef locations of the four major reef regions in India as of March 2011, alongside a review of available reef health data since...

  1. Tourism, Reef Condition and Visitor Satisfaction in Watamu Marine ...

    African Journals Online (AJOL)

    Abstract—Reef-based tourism is known to put environmental pressure on reefs but its consequences on the ecological and economic sustainability of Marine. Protected Areas is unknown. Previous research suggests that, if reef conditions decline, then tourism on a reef will also suffer, but is this always the case? This.

  2. Patterns of coral species richness and reef connectivity in Malaysia

    NARCIS (Netherlands)

    Waheed, Z.

    2016-01-01

    Much remains to be discovered about the biodiversity of coral reefs in Malaysia, making this area a priority for coral reef research. This thesis aims to provide insights into the patterns of reef coral species richness and the degree of reef connectivity across Malaysia. For the species richness

  3. Effects of coral reef benthic primary producers on dissolved organic carbon and microbial activity.

    Directory of Open Access Journals (Sweden)

    Andreas F Haas

    Full Text Available Benthic primary producers in marine ecosystems may significantly alter biogeochemical cycling and microbial processes in their surrounding environment. To examine these interactions, we studied dissolved organic matter release by dominant benthic taxa and subsequent microbial remineralization in the lagoonal reefs of Moorea, French Polynesia. Rates of photosynthesis, respiration, and dissolved organic carbon (DOC release were assessed for several common benthic reef organisms from the backreef habitat. We assessed microbial community response to dissolved exudates of each benthic producer by measuring bacterioplankton growth, respiration, and DOC drawdown in two-day dark dilution culture incubations. Experiments were conducted for six benthic producers: three species of macroalgae (each representing a different algal phylum: Turbinaria ornata--Ochrophyta; Amansia rhodantha--Rhodophyta; Halimeda opuntia--Chlorophyta, a mixed assemblage of turf algae, a species of crustose coralline algae (Hydrolithon reinboldii and a dominant hermatypic coral (Porites lobata. Our results show that all five types of algae, but not the coral, exuded significant amounts of labile DOC into their surrounding environment. In general, primary producers with the highest rates of photosynthesis released the most DOC and yielded the greatest bacterioplankton growth; turf algae produced nearly twice as much DOC per unit surface area than the other benthic producers (14.0±2.8 µmol h⁻¹ dm⁻², stimulating rapid bacterioplankton growth (0.044±0.002 log10 cells h⁻¹ and concomitant oxygen drawdown (0.16±0.05 µmol L⁻¹ h⁻¹ dm⁻². Our results demonstrate that benthic reef algae can release a significant fraction of their photosynthetically-fixed carbon as DOC, these release rates vary by species, and this DOC is available to and consumed by reef associated microbes. These data provide compelling evidence that benthic primary producers differentially influence

  4. Return of the coral reef hypothesis: basin to shelf partitioning of CaCO3 and its effect on atmospheric CO2.

    Science.gov (United States)

    Opdyke, B N; Walker, J C

    1992-08-01

    Differences in the rate of coral reef carbonate deposition from the Pleistocene to the Holocene may account for the Quaternary variation of atmospheric CO2. Volumes of carbonate associated with Holocene reefs require an average deposition rate of 2.0 x 10(13) mol/yr for the past 5 ka. In light of combined riverine, midocean ridge, and ground-water fluxes of calcium to the oceans of 2.3 x 10(13) mol/yr, the current flux of calcium carbonate to pelagic sediments must be far below the Pleistocene average of 1.2 x 10(13) mol/yr. We suggest that sea-level change shifts the locus of carbonate deposition from the deep sea to the shelves as the normal glacial-interglacial pattern of deposition for Quaternary global carbonates. To assess the impact of these changes on atmospheric CO2, a simple numerical simulation of the global carbon cycle was developed. Atmospheric CO2 as well as calcite saturation depth and sediment responses to these carbonate deposition changes are examined. Atmospheric CO2 changes close to those observed in the Vostok ice core, approximately 80 ppm CO2, for the Quaternary are observed as well as the approximate depth changes in percent carbonate of sediments measured in the Pacific Ocean over the same time interval.

  5. Potential influence of sea cucumbers on coral reef CaCO3 budget: A case study at One Tree Reef

    Science.gov (United States)

    Schneider, Kenneth; Silverman, Jacob; Woolsey, Erika; Eriksson, Hampus; Byrne, Maria; Caldeira, Ken

    2011-12-01

    To endure, coral reefs must accumulate CaCO3 at a rate greater or equal than the sum of mechanically, biologically, and chemically mediated erosion rates. We investigated the potential role of holothurians on the CaCO3 balance of a coral reef. These deposit feeders process carbonate sand and rubble through their digestive tract and dissolve CaCO3 as part of their digestive process. In aquarium incubations with Stichopus herrmanni and Holothuria leucospilota total alkalinity increased by 97 ± 13 and 47 ± 7 μmol kg-1, respectively. This increase was due to CaCO3 dissolution, 81 ± 13 and 34 ± 6 μmol kg-1 and ammonia secretion, 16 ± 2 and 14 ± 2μmol kg-1, respectively, for these species. Surveys conducted at a long-term monitoring site of community calcification (DK13) on One Tree Reef indicated that the density of sea cucumbers was approximately 1 individual m-2. We used these data and data from surveys at Shark Alley to estimate the dissolution of CaCO3 by the sea cucumbers at both sites. At DK13 the sea cucumber population was estimated to be responsible for nearly 50% of the nighttime CaCO3 dissolution, while in Shark Alley for most of the nighttime dissolution. Thus, in a healthy reef, bioeroders dissolution of CaCO3 sediment appears to be an important component of the natural CaCO3 turnover and a substantial source of alkalinity as well. This additional alkalinity could partially buffer changes in seawater pH associated with increasing atmospheric CO2 locally, thus reducing the impact of ocean acidification on coral growth.

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

    Science.gov (United States)

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

    2016-04-01

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

  7. Global warming and coral reefs

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.

    , notably at Ratnagiri. Malwan. Redi Port and Vizhingam. Relic reefs with living herm<:ltypic corals at depths ranging fror:l 25 to 45m are the Gaves hani Bank off~\\angalore,and the submerged banks (Bass<:ls de Pedro. Sesostris Bank and Cora Divh... the snore (Qaslm and Wafar, 1979). The other representative Sea le\\lel Variation 417 of the extensive reelS of the outer shelf that survived Pleistocene drowning is the Gaveshani Bank, fanhc: south (J 3° 24' N; 73° 45' E), about 100 km off \\1 ar:ga lore...

  8. The Changing Face of Plio-Pleistocene Reef Margins: Results of the Dominican Republic Drilling Project (DRDP)

    Science.gov (United States)

    Klaus, J.; McNeill, D. F.; Díaz, V.; Swart, P. K.; Pourmand, A.; Grasmueck, M.; Eberli, G. P.

    2013-12-01

    Fringing reef margins of the Caribbean display a characteristic zonation in which Acropora palmata dominates shallow high-energy reef crests and Acropora cervicornis calmer fore-reef slopes and backreef lagoons. The dominance of acroporids across this zonation has been attributed to growth rates 5-100 times faster than other corals. However, the dominance and high accretion potential of acroporid reefs has a relatively recent geologic origin. Caribbean reefs changed profoundly in taxonomic composition, diversity, and dominance structure during late Pliocene and Pleistocene climatic change. These changes coincide with protracted climatic deterioration and cooling between 2.0 to 0.8 Ma, and the onset of high amplitude sea-level fluctuations ~400 ka. The Dominican Republic Drilling Project (DRDP) was initiated to determine how climate change and global high-amplitude sea level changes influenced depositional patterns in Pliocene to Recent reef systems of the Caribbean. A transect of 7 core borings (~700 m total depth) were collected along a transect of the southern coast of the DR in conjunction with over 20 km of ground penetrating radar (GPR) lines. New age constraints based on U/Th geochronometry and radiogenic Sr isotopes, combined with depositional lithofacies, faunal indicators, stable isotope profiles and GPR data have allowed us to correlate between wells and define the internal anatomy and stratal geometry of the individual reef sigmoids and sigmoid sets. The stacking of these sigmoid-shaped reefs produce lateral progradation of approximately 15 km with geometries that generally follow the highstand systems tract model of Pomar and Ward (1994). Based on existing age models eccentricity (high amplitude 100 kyr) sigmoids display increased aggradation and progradation potential compared to reef cycles driven by obliquity (41 kyr).

  9. Microstructural aspects of manganese metal during its electrodeposition from sulphate solutions in the presence of quaternary amines

    International Nuclear Information System (INIS)

    Padhy, Subrat Kumar; Patnaik, P.; Tripathy, B.C.; Bhattacharya, I.N.

    2015-01-01

    Graphical abstract: - Highlights: • Quaternary amines produced smooth and bright manganese electrodeposits. • TEABr produced smooth and bright deposits with euhedral shaped crystals. • TBABr produced dendritic deposits with elongated poly-nodular crystals. • All the quaternary amines behaved as cathode polarisers. • TEABr was found to be the most efficient organic additive. - Abstract: In the present study investigation was made on the electrodeposition of manganese from sulphate solutions in the presence of quaternary amines TEABr, TPABr and TBABr. The concentrations of these additives were varied over a relatively broad range to evaluate their effect on the deposit morphology and preferred crystal orientations of the electrodeposited metal. TEABr resulted in bright and smooth manganese electrodeposits giving euhedral shape to the crystals with distinct triple junction points. TPABr also showed similar results at lower concentrations. However, TBABr resulted in the formation of dendritic growths with elongated poly-nodular crystals similar to that of Paragorgia corals having uniform multistep growths. The presence of these quaternary amines in the electrolyte causes polarisation of the cathode. TBABr being the strongest cathode polariser adsorbs strongly on the cathode resulting in poor deposit quality. TEABr was found to be the most efficient additive producing the desired quality manganese electrodeposit

  10. Geomorphology and sediment transport on a submerged back-reef sand apron: One Tree Reef, Great Barrier Reef

    Science.gov (United States)

    Harris, Daniel L.; Vila-Concejo, Ana; Webster, Jody M.

    2014-10-01

    Back-reef sand aprons are conspicuous and dynamic sedimentary features in coral reef systems. The development of these features influences the evolution and defines the maturity of coral reefs. However, the hydrodynamic processes that drive changes on sand aprons are poorly understood with only a few studies directly assessing sediment entrainment and transport. Current and wave conditions on a back-reef sand apron were measured during this study and a digital elevation model was developed through topographic and bathymetric surveying of the sand apron, reef flats and lagoon. The current and wave processes that may entrain and transport sediment were assessed using second order small amplitude (Stokes) wave theory and Shields equations. The morphodynamic interactions between current flow and geomorphology were also examined. The results showed that sediment transport occurs under modal hydrodynamic conditions with waves the main force entraining sediment rather than average currents. A morphodynamic relationship between current flow and geomorphology was also observed with current flow primarily towards the lagoon in shallow areas of the sand apron and deeper channel-like areas directing current off the sand apron towards the lagoon or the reef crest. These results show that the short-term mutual interaction of hydrodynamics and geomorphology in coral reefs can result in morphodynamic equilibrium.

  11. Monitoring the impacts of Ocean Acidification on coral reef bioerosion: challenges, methods, recommendations

    Science.gov (United States)

    Enochs, I.; Manzello, D.; Carlton, R.

    2013-05-01

    Coral reef habitats exist as a dynamic balance between the additive process of calcification and the destructive effects of erosion. A disruption to either the positive or negative side of the coral reef carbonate budget can push a reef system towards rapid collapse. It is well understood that Ocean Acidification (OA) may impair calcification and emerging experimental evidence suggests that it will likely increase the erosive potential of a diverse suite of bioeroding taxa. This may lead to previously unforeseen scenarios where reef framework degradation occurs at a faster pace than that predicted by more simplistic models, resulting from the multifaceted impacts of both slower coral growth and enhanced rates of habitat erosion. As such, it is of paramount importance that monitoring plans tasked with assessing reef resilience to climate change and OA incorporate methods for quantifying bioerosion. This is a complex undertaking as reef ecosystem bioerosion is the result of numerous behaviors, employed by diverse flora and fauna, operating at vastly different scales. Furthermore, these erosive processes are highly variable, dependent on seasonal fluctuations and differing between reef regions, species, individuals, and even the physical characteristics of the substrates acted upon. The strengths and weaknesses of existing bioerosion monitoring methodologies are discussed, ranging from quantification of single species erosion rates to multi-phyletic census-based approaches. Traditional techniques involving the weight change of carbonate blocks are compared alongside more modern methodologies such as micro computed tomography. Finally, recommendations are made for a comprehensive monitoring strategy, incorporating multiple methodologies in a time and cost-effective manner.

  12. Using otolith microchemistry and shape to assess the habitat value of oil structures for reef fish.

    Science.gov (United States)

    Fowler, Ashley M; Macreadie, Peter I; Bishop, David P; Booth, David J

    2015-05-01

    Over 7500 oil and gas structures (e.g. oil platforms) are installed in offshore waters worldwide and many will require decommissioning within the next two decades. The decision to remove such structures or turn them into reefs (i.e. 'rigs-to-reefs') hinges on the habitat value they provide, yet this can rarely be determined because the residency of mobile species is difficult to establish. Here, we test a novel solution to this problem for reef fishes; the use of otolith (earstone) properties to identify oil structures of residence. We compare the otolith microchemistry and otolith shape of a site-attached coral reef fish (Pseudanthias rubrizonatus) among four oil structures (depth 82-135 m, separated by 9.7-84.2 km) on Australia's North West Shelf to determine if populations developed distinct otolith properties during their residency. Microchemical signatures obtained from the otolith edge using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) differed among oil structures, driven by elements Sr, Ba and Mn, and to a lesser extent Mg and Fe. A combination of microchemical data from the otolith edge and elliptical Fourier (shape) descriptors allowed allocation of individuals to their 'home' structure with moderate accuracy (overall allocation accuracy: 63.3%, range: 45.5-78.1%), despite lower allocation accuracies for each otolith property in isolation (microchemistry: 47.5%, otolith shape: 45%). Site-specific microchemical signatures were also stable enough through time to distinguish populations during 3 separate time periods, suggesting that residence histories could be recreated by targeting previous growth zones in the otolith. Our results indicate that reef fish can develop unique otolith properties during their residency on oil structures which may be useful for assessing the habitat value of individual structures. The approach outlined here may also be useful for determining the residency of reef fish on artificial reefs, which would

  13. The demise of a major Acropora palmata bank-barrier reef off the southeast coast of Barbados, West Indies

    Science.gov (United States)

    MacIntyre, I. G.; Glynn, P. W.; Toscano, M. A.

    2007-12-01

    Formerly attributed to human activity, the demise of a bank-barrier reef off southeastern Barbados known as Cobbler’s Reef is now thought to be largely the result of late Holocene, millennial-scale storm damage. Eleven surface samples of the reef crest coral Acropora palmata from nine sites along its 15-km length plot above the western Atlantic sea-level curve from 3,000 to 4,500 cal years ago (calibrated, calendar 14C years). These elevated clusters suggest that the reef complex suffered extensive storm damage during this period. The constant heavy wave action typical of this area and consequent low herbivory maintain conditions favoring algal growth, thereby limiting the reestablishment of post-storm reef framework. Site descriptions and detailed line surveys show a surface now composed mainly of reworked fragments of A. palmata covered with algal turf, macroalgae and crustose coralline algae. The reef contains no live A. palmata and only a few scattered coral colonies consisting primarily of Diploria spp . and Porites astreoides, along with the hydrocoral Millepora complanata. A few in situ framework dates plot at expected depths for normal coral growth below the sea-level curve during and after the period of intense storm activity. The most recent of these in situ samples are 320 and 400 cal years old. Corals of this late period likely succumbed to high turbidity associated with land clearance for sugarcane agriculture in the mid-1600s.

  14. The coral reef crisis: the critical importance of<350 ppm CO2.

    Science.gov (United States)

    Veron, J E N; Hoegh-Guldberg, O; Lenton, T M; Lough, J M; Obura, D O; Pearce-Kelly, P; Sheppard, C R C; Spalding, M; Stafford-Smith, M G; Rogers, A D

    2009-10-01

    Temperature-induced mass coral bleaching causing mortality on a wide geographic scale started when atmospheric CO(2) levels exceeded approximately 320 ppm. When CO(2) levels reached approximately 340 ppm, sporadic but highly destructive mass bleaching occurred in most reefs world-wide, often associated with El Niño events. Recovery was dependent on the vulnerability of individual reef areas and on the reef's previous history and resilience. At today's level of approximately 387 ppm, allowing a lag-time of 10 years for sea temperatures to respond, most reefs world-wide are committed to an irreversible decline. Mass bleaching will in future become annual, departing from the 4 to 7 years return-time of El Niño events. Bleaching will be exacerbated by the effects of degraded water-quality and increased severe weather events. In addition, the progressive onset of ocean acidification will cause reduction of coral growth and retardation of the growth of high magnesium calcite-secreting coralline algae. If CO(2) levels are allowed to reach 450 ppm (due to occur by 2030-2040 at the current rates), reefs will be in rapid and terminal decline world-wide from multiple synergies arising from mass bleaching, ocean acidification, and other environmental impacts. Damage to shallow reef communities will become extensive with consequent reduction of biodiversity followed by extinctions. Reefs will cease to be large-scale nursery grounds for fish and will cease to have most of their current value to humanity. There will be knock-on effects to ecosystems associated with reefs, and to other pelagic and benthic ecosystems. Should CO(2) levels reach 600 ppm reefs will be eroding geological structures with populations of surviving biota restricted to refuges. Domino effects will follow, affecting many other marine ecosystems. This is likely to have been the path of great mass extinctions of the past, adding to the case that anthropogenic CO(2) emissions could trigger the Earth's sixth

  15. CORAL REEF BIOLOGICAL CRITERIA: USING THE CLEAN ...

    Science.gov (United States)

    Coral reefs are declining at unprecedented rates worldwide due to multiple interactive stressors including climate change and land-based sources of pollution. The Clean Water Act (CWA) can be a powerful legal instrument for protecting water resources, including the biological inhabitants of coral reefs. The objective of the CWA is to restore and maintain the chemical, physical and biological integrity of water resources. Coral reef protection and restoration under the Clean Water Act begins with water quality standards - provisions of state or Federal law that consist of a designated use(s) for the waters of the United States and water quality criteria sufficient to protect the uses. Aquatic life use is the designated use that is measured by biological criteria (biocriteria). Biocriteria are expectations set by a jurisdiction for the quality and quantity of living aquatic resources in a defined waterbody. Biocriteria are an important addition to existing management tools for coral reef ecosystems. The Technical Support Document “Coral Reef Biological Criteria: Using the Clean Water Act to Protect a National Treasure” will provide a framework to aid States and Territories in their development, adoption, and implementation of coral reef biocriteria in their respective water quality standards. The Technical Support Document “Coral Reef Biological Criteria: Using the Clean Water Act to Protect a National Treasure” will provide a framework for coral re

  16. Overfishing and nutrient pollution interact with temperature to disrupt coral reefs down to microbial scales.

    Science.gov (United States)

    Zaneveld, Jesse R; Burkepile, Deron E; Shantz, Andrew A; Pritchard, Catharine E; McMinds, Ryan; Payet, Jérôme P; Welsh, Rory; Correa, Adrienne M S; Lemoine, Nathan P; Rosales, Stephanie; Fuchs, Corinne; Maynard, Jeffrey A; Thurber, Rebecca Vega

    2016-06-07

    Losses of corals worldwide emphasize the need to understand what drives reef decline. Stressors such as overfishing and nutrient pollution may reduce resilience of coral reefs by increasing coral-algal competition and reducing coral recruitment, growth and survivorship. Such effects may themselves develop via several mechanisms, including disruption of coral microbiomes. Here we report the results of a 3-year field experiment simulating overfishing and nutrient pollution. These stressors increase turf and macroalgal cover, destabilizing microbiomes, elevating putative pathogen loads, increasing disease more than twofold and increasing mortality up to eightfold. Above-average temperatures exacerbate these effects, further disrupting microbiomes of unhealthy corals and concentrating 80% of mortality in the warmest seasons. Surprisingly, nutrients also increase bacterial opportunism and mortality in corals bitten by parrotfish, turning normal trophic interactions deadly for corals. Thus, overfishing and nutrient pollution impact reefs down to microbial scales, killing corals by sensitizing them to predation, above-average temperatures and bacterial opportunism.

  17. Image Fusion Applied to Satellite Imagery for the Improved Mapping and Monitoring of Coral Reefs: a Proposal

    Science.gov (United States)

    Gholoum, M.; Bruce, D.; Hazeam, S. Al

    2012-07-01

    A coral reef ecosystem, one of the most complex marine environmental systems on the planet, is defined as biologically diverse and immense. It plays an important role in maintaining a vast biological diversity for future generations and functions as an essential spawning, nursery, breeding and feeding ground for many kinds of marine species. In addition, coral reef ecosystems provide valuable benefits such as fisheries, ecological goods and services and recreational activities to many communities. However, this valuable resource is highly threatened by a number of environmental changes and anthropogenic impacts that can lead to reduced coral growth and production, mass coral mortality and loss of coral diversity. With the growth of these threats on coral reef ecosystems, there is a strong management need for mapping and monitoring of coral reef ecosystems. Remote sensing technology can be a valuable tool for mapping and monitoring of these ecosystems. However, the diversity and complexity of coral reef ecosystems, the resolution capabilities of satellite sensors and the low reflectivity of shallow water increases the difficulties to identify and classify its features. This paper reviews the methods used in mapping and monitoring coral reef ecosystems. In addition, this paper proposes improved methods for mapping and monitoring coral reef ecosystems based on image fusion techniques. This image fusion techniques will be applied to satellite images exhibiting high spatial and low to medium spectral resolution with images exhibiting low spatial and high spectral resolution. Furthermore, a new method will be developed to fuse hyperspectral imagery with multispectral imagery. The fused image will have a large number of spectral bands and it will have all pairs of corresponding spatial objects. This will potentially help to accurately classify the image data. Accuracy assessment use ground truth will be performed for the selected methods to determine the quality of the

  18. IMAGE FUSION APPLIED TO SATELLITE IMAGERY FOR THE IMPROVED MAPPING AND MONITORING OF CORAL REEFS: A PROPOSAL

    Directory of Open Access Journals (Sweden)

    M. Gholoum

    2012-07-01

    Full Text Available A coral reef ecosystem, one of the most complex marine environmental systems on the planet, is defined as biologically diverse and immense. It plays an important role in maintaining a vast biological diversity for future generations and functions as an essential spawning, nursery, breeding and feeding ground for many kinds of marine species. In addition, coral reef ecosystems provide valuable benefits such as fisheries, ecological goods and services and recreational activities to many communities. However, this valuable resource is highly threatened by a number of environmental changes and anthropogenic impacts that can lead to reduced coral growth and production, mass coral mortality and loss of coral diversity. With the growth of these threats on coral reef ecosystems, there is a strong management need for mapping and monitoring of coral reef ecosystems. Remote sensing technology can be a valuable tool for mapping and monitoring of these ecosystems. However, the diversity and complexity of coral reef ecosystems, the resolution capabilities of satellite sensors and the low reflectivity of shallow water increases the difficulties to identify and classify its features. This paper reviews the methods used in mapping and monitoring coral reef ecosystems. In addition, this paper proposes improved methods for mapping and monitoring coral reef ecosystems based on image fusion techniques. This image fusion techniques will be applied to satellite images exhibiting high spatial and low to medium spectral resolution with images exhibiting low spatial and high spectral resolution. Furthermore, a new method will be developed to fuse hyperspectral imagery with multispectral imagery. The fused image will have a large number of spectral bands and it will have all pairs of corresponding spatial objects. This will potentially help to accurately classify the image data. Accuracy assessment use ground truth will be performed for the selected methods to determine

  19. Diving down the reefs? Intensive diving tourism threatens the reefs of the northern Red Sea

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Ott, Jörg A.

    2008-01-01

    Intensive recreational SCUBA diving threatens coral reef ecosystems. The reefs at Dahab, South Sinai, Egypt, are among the world’s most dived (>30,000dives y−1). We compared frequently dived sites to sites with no or little diving. Benthic communities and condition of corals were examined...... to intensive SCUBA diving showed a significantly higher number of broken and damaged corals and significantly lower coral cover. Reef crest coral communities were significantly more affected than those of the reef slope: 95% of the broken colonies were branching ones. No effect of diving on the abundance...... by the point intercept sampling method in the reef crest zone (3 m) and reef slope zone (12 m). Additionally, the abundance of corallivorous and herbivorous fish was estimated based on the visual census method. Sediments traps recorded the sedimentation rates caused by SCUBA divers. Zones subject...

  20. Design, synthesis of novel chitosan derivatives bearing quaternary phosphonium salts and evaluation of antifungal activity.

    Science.gov (United States)

    Tan, Wenqiang; Zhang, Jingjing; Luan, Fang; Wei, Lijie; Chen, Yuan; Dong, Fang; Li, Qing; Guo, Zhanyong

    2017-09-01

    Two novel chitosan derivatives modified with quaternary phosphonium salts were successfully synthesized, including tricyclohexylphosphonium acetyl chitosan chloride (TCPACSC) and triphenylphosphonium acetyl chitosan chloride (TPPACSC), and characterized by FTIR, 1 H NMR, and 13 C NMR spectra. The degree of substitution was also calculated by elemental analysis results. Their antifungal activities against Colletotrichum lagenarium, Watermelon fusarium, and Fusarium oxysporum were investigated in vitro using the radial growth assay, minimal inhibitory concentration, and minimum bactericidal concentration assay. The fungicidal assessment revealed that the synthesized chitosan derivatives had superior antifungal activity compared with chitosan. Especially, TPPACSC exhibited the best antifungal property with inhibitory indices of over 75% at 1.0mg/mL. The results obviously showed that quaternary phosphonium groups could effectively enhance antifungal activity of the synthesized chitosan derivatives. Meanwhile, it was also found that their antifungal activity was influenced by electron-withdrawing ability of the quaternary phosphonium salts. The synthetic strategy described here could be utilized for the development of chitosan as antifungal biomaterials. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Synthesis of inulin derivatives with quaternary phosphonium salts and their antifungal activity.

    Science.gov (United States)

    Chen, Yuan; Tan, Wenqiang; Li, Qing; Dong, Fang; Gu, Guodong; Guo, Zhanyong

    2018-03-13

    Inulin is a kind of renewable and biodegradable carbohydrate with good water solubility and numerous physiological functions. For further utilization of inulin, chemical modification can be applied to improve its bioactivities. In this paper, five novel inulin derivatives were synthesized via chemical modification with quaternary phosphonium salt. Their antifungal activity against three kinds of plant pathogens including Colletotrichum lagenarium, Phomopsis asparagi, and Fusarium oxysporum was assessed with radial growth assay in vitro. Results revealed that all the inulin derivatives exhibited improved antifungal activity compared with inulin. Particularly, inulin modified with triphenylphosphine (TPhPAIL) exhibited the best antifungal activity with inhibitory indices of 80.0%, 78.8%, and 87.4% against Colletotrichum lagenarium, Phomopsis asparagi, and Fusarium oxysporum at 1.0mg/mL respectively. The results clearly showed that chemical modification of inulin with quaternary phosphonium salt could efficiently improve derivatives' antifungal activity. Further analysis of results indicated that the antifungal activity was influenced by alkyl chain length or electron-withdrawing ability of the grafted quaternary phosphonium salts. Longer alkyl chain lengths or the stronger electron-withdrawing groups would lead to enhanced antifungal efficacy. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Assessment of human activities impact on groundwater quality discharging into a reef lagoon

    Science.gov (United States)

    Rebolledo-Vieyra, M.; Hernandez, L.; Paytan, A.; Merino-Ibarra, M.; Lecossec, A.; Soto, M.

    2010-03-01

    The Eastern coast of the Yucatan Peninsula has the fastest growth rate in Mexico and groundwater is the only source of drinking water in the region. The consequences of the lack of proper infrastructure to collect and treat wastewater and the impact of human activities on the quality of groundwater are addressed. The groundwater in the coastal aquifer of Quintana Roo (SE Mexico) discharges directly into the ocean (Submarine Groundwater Discharges). In addition, the coral reef of the Eastern Yucatan Peninsula is part of the Mesoamerican Coral Reef System, one of the largest in the world. The interaction of the reef-lagoon hydraulics with the coastal aquifer of Puerto Morelos (NE Yucatan Peninsula), and a major input of NH4, SO4, SiO2, as a consequence of the use of septic tanks and the lack of modern wastewater treatment plants are presented. A conceptual model of the coastal aquifer was developed, in order to explain how the human activities are impacting directly on the groundwater quality that, potentially, will have a direct impact on the coral reef. The protection and conservation of coral reefs must be directly related with a policy of sound management of coastal aquifers and wastewater treatment.

  3. Reefs under Siege—the Rise, Putative Drivers, and Consequences of Benthic Cyanobacterial Mats

    Directory of Open Access Journals (Sweden)

    Amanda K. Ford

    2018-02-01

    Full Text Available Benthic cyanobacteria have commonly been a small but integral component of coral reef ecosystems, fulfilling the critical function of introducing bioavailable nitrogen to an inherently oligotrophic environment. Though surveys may have previously neglected benthic cyanobacteria, or grouped them with more conspicuous benthic groups, emerging evidence strongly indicates that they are becoming increasingly prevalent on reefs worldwide. Some species can form mats comprised by a diverse microbial consortium which allows them to exist across a wide range of environmental conditions. This review evaluates the putative driving factors of increasing benthic cyanobacterial mats, including climate change, declining coastal water quality, iron input, and overexploitation of key consumer and ecosystem engineer species. Ongoing global environmental change can increase growth rates and toxin production of physiologically plastic benthic cyanobacterial mats, placing them at a considerable competitive advantage against reef-building corals. Once established, strong ecological feedbacks [e.g., inhibition of coral recruitment, release of dissolved organic carbon (DOC] reinforce reef degradation. The review also highlights previously overlooked implications of mat proliferation, which can extend beyond reef health and affect human health and welfare. Though identifying (opportunistic consumers of mats remains a priority, their perceived low palatability implies that herbivore management alone may be insufficient to control their proliferation and must be accompanied by local measures to improve water quality and watershed management.

  4. Seismic evidence of glacial-age river incision into the Tahaa barrier reef, French Polynesia

    Science.gov (United States)

    Toomey, Michael; Woodruff, Jonathan D.; Ashton, Andrew D.; Perron, J. Taylor

    2016-01-01

    Rivers have long been recognized for their ability to shape reef-bound volcanic islands. On the time-scale of glacial–interglacial sea-level cycles, fluvial incision of exposed barrier reef lagoons may compete with constructional coral growth to shape the coastal geomorphology of ocean islands. However, overprinting of Pleistocene landscapes by Holocene erosion or sedimentation has largely obscured the role lowstand river incision may have played in developing the deep lagoons typical of modern barrier reefs. Here we use high-resolution seismic imagery and core stratigraphy to examine how erosion and/or deposition by upland drainage networks has shaped coastal morphology on Tahaa, a barrier reef-bound island located along the Society Islands hotspot chain in French Polynesia. At Tahaa, we find that many channels, incised into the lagoon floor during Pleistocene sea-level lowstands, are located near the mouths of upstream terrestrial drainages. Steeper antecedent topography appears to have enhanced lowstand fluvial erosion along Tahaa's southwestern coast and maintained a deep pass. During highstands, upland drainages appear to contribute little sediment to refilling accommodation space in the lagoon. Rather, the flushing of fine carbonate sediment out of incised fluvial channels by storms and currents appears to have limited lagoonal infilling and further reinforced development of deep barrier reef lagoons during periods of highstand submersion.

  5. Keep up or drown: adjustment of western Pacific coral reefs to sea-level rise in the 21st century.

    Science.gov (United States)

    van Woesik, R; Golbuu, Y; Roff, G

    2015-07-01

    Since the Mid-Holocene, some 5000 years ago, coral reefs in the Pacific Ocean have been vertically constrained by sea level. Contemporary sea-level rise is releasing these constraints, providing accommodation space for vertical reef expansion. Here, we show that Porites microatolls, from reef-flat environments in Palau (western Pacific Ocean), are 'keeping up' with contemporary sea-level rise. Measurements of 570 reef-flat Porites microatolls at 10 locations around Palau revealed recent vertical skeletal extension (78±13 mm) over the last 6-8 years, which is consistent with the timing of the recent increase in sea level. We modelled whether microatoll growth rates will potentially 'keep up' with predicted sea-level rise in the near future, based upon average growth, and assuming a decline in growth for every 1°C increase in temperature. We then compared these estimated extension rates with rates of sea-level rise under four Representative Concentration Pathways (RCPs). Our model suggests that under low-mid RCP scenarios, reef-coral growth will keep up with sea-level rise, but if greenhouse gas concentrations exceed 670 ppm atmospheric CO2 levels and with +2.2°C sea-surface temperature by 2100 (RCP 6.0 W m(-2)), our predictions indicate that Porites microatolls will be unable to keep up with projected rates of sea-level rise in the twenty-first century.

  6. Projecting of wave height and water level on reef-lined coasts due to intensified tropical cyclones and sea level rise in Palau to 2100

    Directory of Open Access Journals (Sweden)

    C. Hongo

    2018-03-01

    Full Text Available Tropical cyclones (TCs and sea level rise (SLR cause major problems including beach erosion, saltwater intrusion into groundwater, and damage to infrastructure in coastal areas. The magnitude and extent of damage is predicted to increase as a consequence of future climate change and local factors. Upward reef growth has attracted attention for its role as a natural breakwater, reducing the risks of natural disasters to coastal communities. However, projections of change in the risk to coastal reefs under conditions of intensified TCs and SLR are poorly quantified. In this study we projected the wave height and water level on Melekeok reef in the Palau Islands by 2100, based on wave simulations under intensified TCs (significant wave height at the outer ocean: SWHo = 8.7–11.0 m; significant wave period at the outer ocean: SWPo = 13–15 s and SLR (0.24–0.98 m. To understand effects of upward reef growth on the reduction of the wave height and water level, the simulation was conducted for two reef condition scenarios: a degraded reef and a healthy reef. Moreover, analyses of reef growth based on a drilled core provided an assessment of the coral community and rate of reef production necessary to reduce the risk from TCs and SLR on the coastal areas. According to our calculations under intensified TCs and SLR by 2100, significant wave heights at the reef flat (SWHr will increase from 1.05–1.24 m at present to 2.14 m if reefs are degraded. Similarly, by 2100 the water level at the shoreline (WLs will increase from 0.86–2.10 m at present to 1.19–3.45 m if reefs are degraded. These predicted changes will probably cause beach erosion, saltwater intrusion into groundwater, and damage to infrastructure, because the coastal village is located at  ∼ 3 m above the present mean sea level. These findings imply that even if the SWHr is decreased by only 0.1 m by upward reef growth, it will probably reduce the risks of

  7. Projecting of wave height and water level on reef-lined coasts due to intensified tropical cyclones and sea level rise in Palau to 2100

    Science.gov (United States)

    Hongo, Chuki; Kurihara, Haruko; Golbuu, Yimnang

    2018-03-01

    Tropical cyclones (TCs) and sea level rise (SLR) cause major problems including beach erosion, saltwater intrusion into groundwater, and damage to infrastructure in coastal areas. The magnitude and extent of damage is predicted to increase as a consequence of future climate change and local factors. Upward reef growth has attracted attention for its role as a natural breakwater, reducing the risks of natural disasters to coastal communities. However, projections of change in the risk to coastal reefs under conditions of intensified TCs and SLR are poorly quantified. In this study we projected the wave height and water level on Melekeok reef in the Palau Islands by 2100, based on wave simulations under intensified TCs (significant wave height at the outer ocean: SWHo = 8.7-11.0 m; significant wave period at the outer ocean: SWPo = 13-15 s) and SLR (0.24-0.98 m). To understand effects of upward reef growth on the reduction of the wave height and water level, the simulation was conducted for two reef condition scenarios: a degraded reef and a healthy reef. Moreover, analyses of reef growth based on a drilled core provided an assessment of the coral community and rate of reef production necessary to reduce the risk from TCs and SLR on the coastal areas. According to our calculations under intensified TCs and SLR by 2100, significant wave heights at the reef flat (SWHr) will increase from 1.05-1.24 m at present to 2.14 m if reefs are degraded. Similarly, by 2100 the water level at the shoreline (WLs) will increase from 0.86-2.10 m at present to 1.19-3.45 m if reefs are degraded. These predicted changes will probably cause beach erosion, saltwater intrusion into groundwater, and damage to infrastructure, because the coastal village is located at ˜ 3 m above the present mean sea level. These findings imply that even if the SWHr is decreased by only 0.1 m by upward reef growth, it will probably reduce the risks of costal damages. Our results showed that a healthy reef

  8. Coral Reef Color: Remote and In-Situ Imaging Spectroscopy of Reef Structure and Function

    Science.gov (United States)

    Hochberg, E. J.

    2016-02-01

    Coral reefs are threatened at local to global scales by a litany of anthropogenic impacts, including overfishing, coastal development, marine and watershed pollution, rising ocean temperatures, and ocean acidification. However, available data for the primary indicator of coral reef condition — proportional cover of living coral — are surprisingly sparse and show patterns that contradict the prevailing understanding of how environment impacts reef condition. Remote sensing is the only available tool for acquiring synoptic, uniform data on reef condition at regional to global scales. Discrimination between coral and other reef benthos relies on narrow wavebands afforded by imaging spectroscopy. The same spectral information allows non-invasive quantification of photosynthetic pigment composition, which shows unexpected phenological trends. There is also potential to link biodiversity with optical diversity, though there has been no effort in that direction. Imaging spectroscopy underlies the light-use efficiency model for reef primary production by quantifying light capture, which in turn indicates biochemical capacity for CO2 assimilation. Reef calcification is strongly correlated with primary production, suggesting the possibility for an optics-based model of that aspect of reef function, as well. By scaling these spectral models for use with remote sensing, we can vastly improve our understanding of reef structure, function, and overall condition across regional to global scales. By analyzing those remote sensing products against ancillary environmental data, we can construct secondary models to predict reef futures in the era of global change. This final point is the objective of CORAL (COral Reef Airborne Laboratory), a three-year project funded under NASA's Earth Venture Suborbital-2 program to investigate the relationship between coral reef condition at the ecosystem scale and various nominal biogeophysical forcing parameters.

  9. Cumulative Human Impacts on Coral Reefs: Assessing Risk and Management Implications for Brazilian Coral Reefs

    OpenAIRE

    Rafael A. Magris; Alana Grech; Robert L. Pressey

    2018-01-01

    Effective management of coral reefs requires strategies tailored to cope with cumulative disturbances from human activities. In Brazil, where coral reefs are a priority for conservation, intensifying threats from local and global stressors are of paramount concern to management agencies. Using a cumulative impact assessment approach, our goal was to inform management actions for coral reefs in Brazil by assessing their exposure to multiple stressors (fishing, land-based activities, coastal de...

  10. Absolute age determination of quaternary faults

    International Nuclear Information System (INIS)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik

    2000-03-01

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results

  11. Absolute age determination of quaternary faults

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2000-03-15

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results.

  12. Quaternary ammonium compounds – New occupational hazards

    Directory of Open Access Journals (Sweden)

    Agnieszka Lipińska-Ojrzanowska

    2014-10-01

    Full Text Available Quaternary ammonium compounds (QACs, quats belong to organic ionic chemical agents which display unique properties of both surfactants and disinfectants. Their wide distribution in the work environment and also in private households brings about new occupational hazards. This paper reviews reports about the health effects of QACs. QACs could play a role of sensitizers and irritants to the skin and mucous membranes. It is suspected that particular QACs can display an immunologic crossreactivity between each other and with other chemical compounds containing ammonium ion, such as muscle relaxants widely used in anesthesia. They may promote the development of airway allergy, however, the background mechanisms are still unclear and need to be further investigated. Until now, a few cases of occupational asthma induced by QACs have been described and their involvement in contact dermatitis has been documented. The possibility of anaphylaxis due to QACs cannot be excluded as well. Med Pr 2014;65(5:675–682

  13. Hydration Structure of the Quaternary Ammonium Cations

    KAUST Repository

    Babiaczyk, Wojtek Iwo

    2010-11-25

    Two indicators of the hydropathicity of small solutes are introduced and tested by molecular dynamics simulations. These indicators are defined as probabilities of the orientation of water molecules\\' dipoles and hydrogen bond vectors, conditional on a generalized distance from the solute suitable for arbitrarily shaped molecules. Using conditional probabilities, it is possible to distinguish features of the distributions in close proximity of the solute. These regions contain the most significant information on the hydration structure but cannot be adequately represented by using, as is usually done, joint distance-angle probability densities. Our calculations show that using our indicators a relative hydropathicity scale for the interesting test set of the quaternary ammonium cations can be roughly determined. © 2010 American Chemical Society.

  14. Permanent 'phase shifts' or reversible declines in coral cover? Lack of recovery of two coral reefs in St. John, US Virgin Islands

    Science.gov (United States)

    Rogers, C.S.; Miller, J.

    2006-01-01

    Caribbean coral reefs have changed dramatically in the last 3 to 4 decades, with significant loss of coral cover and increases in algae. Here we present trends in benthic cover from 1989 to 2003 at 2 reefs (Lameshur Reef and Newfound Reef) off St. John, US Virgin Islands (USVI). Coral cover has declined in the fore-reef zones at both sites, and no recovery is evident. At Lameshur Reef, Hurricane Hugo (1989) caused significant physical damage and loss of coral. We suggest that macroalgae rapidly colonized new substrate made available by this storm and have hindered or prevented growth of adult corals, as well as settlement and survival of new coral recruits. Overfishing of herbivorous fishes in the USVI and loss of shelter for these fishes because of major storms has presumably reduced the levels of herbivory that formerly controlled algal abundance. Coral cover declined at Newfound Reef from 1999 to 2000, most likely because of coral diseases. The trends that we have documented, loss of coral followed by no evidence of recovery, appear similar to findings from other studies in the Caribbean. We need to focus on functional shifts in the resilience of coral reefs that result in their inability to recover from natural and human-caused stressors. ?? Inter-Research 2006.

  15. Soft coral abundance on the central Great Barrier Reef: effects of Acanthaster planci, space availability, and aspects of the physical environment

    Science.gov (United States)

    Fabricius, K. E.

    1997-07-01

    The distribution and abundance of soft coral genera on reefs of the central Great Barrier Reef was investigated in relation to reef position, recent history of disturbance, wave exposure, substratum slope and depth. Eighty-five 25 m long transects were surveyed at 10 m depth on windward sides of 14 mid- and outer-shelf reefs. A further 75 transects in different zones on one mid-shelf reef (Davies Reef) between 5 and 30 m depth were investigated. The crown-of-thorns starfish Acanthaster planci had caused large-scale mortality of scleractinians on eight of these reefs five to ten years prior to the study, and as a result, scleractinian cover was only 35-55% of that on the six unimpacted reefs. On the impacted reefs, stony corals with massive and encrusting growths form had smaller average colony diameters but similar or slightly lower numerical abundance. In contrast, mean colony size, cover and abundance of branching stony corals showed no difference between impacted and unimpacted reefs. Twenty-four genera of soft corals (in eight families) were recorded, and none showed different abundance or cover in areas of former A. planci impact, compared to unaffected sites. Similarly, no difference was detected among locations in the numbers or area cover of sponges, tunicates, zoanthids, Halimeda or other macro-algae. Mean soft coral cover was 2 to 5% at 10 m on sheltered mid-shelf reefs, and 12 to 17% on more current-exposed reefs. Highest cover and abundances generally occurred on platforms of outer-shelf reefs exposed to relatively strong currents but low wave energy. On Davies Reef, cover and colony numbers of the families Nephtheidae and Xeniidae were low within the zone of wave impact, in flow-protected bays and lagoons, on shaded steep slopes, and at depths above 10 and below 25 m. In contrast, distributions of genera of the family Alcyoniidae were not related to these physical parameters. The physical conditions of a large proportion of habitats appear "sub

  16. Vulnerability of coral reef fisheries to a loss of structural complexity.

    Science.gov (United States)

    Rogers, Alice; Blanchard, Julia L; Mumby, Peter J

    2014-05-05

    Coral reefs face a diverse array of threats, from eutrophication and overfishing to climate change. As live corals are lost and their skeletons eroded, the structural complexity of reefs declines. This may have important consequences for the survival and growth of reef fish because complex habitats mediate predator-prey interactions [1, 2] and influence competition [3-5] through the provision of prey refugia. A positive correlation exists between structural complexity and reef fish abundance and diversity in both temperate and tropical ecosystems [6-10]. However, it is not clear how the diversity of available refugia interacts with individual predator-prey relationships to explain emergent properties at the community scale. Furthermore, we do not yet have the ability to predict how habitat loss might affect the productivity of whole reef communities and the fisheries they support. Using data from an unfished reserve in The Bahamas, we find that structural complexity is associated not only with increased fish biomass and abundance, but also with nonlinearities in the size spectra of fish, implying disproportionately high abundances of certain size classes. By developing a size spectrum food web model that links the vulnerability of prey to predation with the structural complexity of a reef, we show that these nonlinearities can be explained by size-structured prey refugia that reduce mortality rates and alter growth rates in different parts of the size spectrum. Fitting the model with data from a structurally complex habitat, we predict that a loss of complexity could cause more than a 3-fold reduction in fishery productivity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Mark and recapture studies of two reef sparids in the Tsitsikamma Coastal National Park

    Directory of Open Access Journals (Sweden)

    C.D. Buxton

    1989-10-01

    Full Text Available A mark and recapture study of two reef sparids, Chrysoblephus laticeps and C. cristiceps, was done in the Tsitsikamma Coastal National Park. Fish were marked with plastic anchor tags and an intraperitoneal injection of oxytetracycline. All recaptures were taken within two kilometres of the tagging locality, suggesting that both species are resident in the area. Growth in length during the period at liberty was very variable and sometimes negative, but was comparable with published growth rates.

  18. [Influence of sediments and tungsten traces on the skeletal structure of Pseudodiploria: a reef building scleractinian coral from the Veracruz Reef System National Park, Mexico].

    Science.gov (United States)

    Colín-García, Norberto A; Campos, Jorge E; Tello-Musi, Jose Luis; Arias-González, Jesús E

    2016-09-01

    Coral reefs are under intense conditions of stress caused by the anthropogenic activities in coastal areas and the increase of human population. Water effluents from urban and industrial areas carry large amounts of sediments and pollutants affecting corals populations, inducing bioerosion, increasing diseases and promoting the development of algae that compete for space with corals. In the Veracruz Reef System National Park (VRSNP) coral reefs are strongly affected by human activities carried out in the area. Gallega and Galleguilla reefs are among the most affected by wastewater discharges from the industrial (petrochemical and metallurgical) and urban areas in their vicinity. To assess the potential impact of this contamination on corals in the VRSNP, a chemical composition and morphology study of 76 Pseudodiploria colonies collected in reefs Gallega, Galleguilla, Isla Verde and Isla de Enmedio, was performed. Fragments of ~10 cm2 were collected and boric acid at 0.5 % was used to remove tissue from the skeleton; once clean, the morphology of each sample was determined with a scanning electron microscope (SEM). Subsequently, to test the chemical composition, an energy dispersion spectroscopy of X-ray chemical microanalysis (EDSX) was performed in the SEM. We found that corals from Gallega and Galleguilla reefs, located closer to human populations, presented high levels of tungsten and the skeleton exhibited multiple perforations. In contrast, corals from the farthest offshore reefs (Isla Verde and Isla de Enmedio) exhibited lower levels of tungsten and fewer perforations in their skeleton. These results demonstrated that anthropogenic activities in the NPVRS are affecting corals skeleton, highly damaging and promoting their bioerosion. The presence of traces of tungsten in the skeleton of corals is an evidence of the damage that waste discharges are causing to coral reefs. Discharges of large amounts of contaminants promoted the growth of harmful species that

  19. MANGROVE-DERIVED NUTRIENTS AND CORAL REEFS

    Science.gov (United States)

    Understanding the consequences of the declining global cover of mangroves due to anthropogenic disturbance necessitates consideration of how mangrove-derived nutrients contribute to threatened coral reef systems. We sampled potential sources of organic matter and a suite of sessi...

  20. EPA Field Manual for Coral Reef Assessments

    Science.gov (United States)

    The Water Quality Research Program (WQRP) supports development of coral reef biological criteria. Research is focused on developing methods and tools to support implementation of legally defensible biological standards for maintaining biological integrity, which is protected by ...

  1. Oyster Reef Projects 1997-2001

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We used a quantitative sampling device to compare nekton use among high-relief live oyster reef, vegetated marsh edge Spartina alterniflora, and nonvegetated bottom...

  2. Oysters and Oyster Reef Communities in Florida.

    Science.gov (United States)

    Knight, Jean; Bly, Joe

    1989-01-01

    The habitat, life history, feeding, classification, anatomy and pearl production of the American oyster (Crassostrea virginica) are presented. A list of other oyster reef inhabitants and predators is provided. Harvest and habitat loss are discussed. (CW)

  3. Reef Fish of Navassa Island 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This record refers to reef fish data collected on the 2004 cruise to Navassa Island National Wildlife Refuge. The random point count method (Bohnsack-Bannerot 1986)...

  4. Ecosystem function and biodiversity on coral reefs

    OpenAIRE

    Ogden, J.; Done, T.; Salvat, B.

    1994-01-01

    The article highlights a workshop held in Key West, Florida in November 1993 attended by a group of 35 international scientists where topics of ecosystem function and biodiversity on coral reefs were discussed.

  5. CRED REA Algal Assessments, Kingman Reef 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines as part of Rapid Ecological Assessments conducted at 15 sites at Kingman Reef in the US...

  6. Coral Reef Watch, Hotspots, 50 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Coral Reef Watch provides Coral Bleaching hotspot maps derived from NOAA's Polar Operational Environmental Satellites (POES). This data provides global area...

  7. Florida Reef Fish Visual Census 1999 - Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set of Excel files contain data from visual sampling of coral reef fish species in the National Marine Sanctuary along the Florida Keys. The dataset...

  8. Extinction vulnerability of coral reef fishes.

    Science.gov (United States)

    Graham, Nicholas A J; Chabanet, Pascale; Evans, Richard D; Jennings, Simon; Letourneur, Yves; Aaron Macneil, M; McClanahan, Tim R; Ohman, Marcus C; Polunin, Nicholas V C; Wilson, Shaun K

    2011-04-01

    With rapidly increasing rates of contemporary extinction, predicting extinction vulnerability and identifying how multiple stressors drive non-random species loss have become key challenges in ecology. These assessments are crucial for avoiding the loss of key functional groups that sustain ecosystem processes and services. We developed a novel predictive framework of species extinction vulnerability and applied it to coral reef fishes. Although relatively few coral reef fishes are at risk of global extinction from climate disturbances, a negative convex relationship between fish species locally vulnerable to climate change vs. fisheries exploitation indicates that the entire community is vulnerable on the many reefs where both stressors co-occur. Fishes involved in maintaining key ecosystem functions are more at risk from fishing than climate disturbances. This finding is encouraging as local and regional commitment to fisheries management action can maintain reef ecosystem functions pending progress towards the more complex global problem of stabilizing the climate. © 2011 Blackwell Publishing Ltd/CNRS.

  9. Comparison of GPS and Quaternary slip rates: Insights from a new Quaternary fault database for Central Asia

    Science.gov (United States)

    Mohadjer, Solmaz; Ehlers, Todd; Bendick, Rebecca; Mutz, Sebastian

    2016-04-01

    Previous studies related to the kinematics of deformation within the India-Asia collision zone have relied on slip rate data for major active faults to test kinematic models that explain the deformation of the region. The slip rate data, however, are generally disputed for many of the first-order faults in the region (e.g., Altyn Tagh and Karakorum faults). Several studies have also challenged the common assumption that geodetic slip rates are representative of Quaternary slip rates. What has received little attention is the degree to which geodetic slip rates relate to Quaternary slip rates for active faults in the India-Asia collision zone. In this study, we utilize slip rate data from a new Quaternary fault database for Central Asia to determine the overall relationship between Quaternary and GPS-derived slip rates for 18 faults. The preliminary analysis investigating this relationship uses weighted least squares and a re-sampling analysis to test the sensitivity of this relationship to different data point attributes (e.g., faults associated with data points and dating methods used for estimating Quaternary slip rates). The resulting sample subsets of data points yield a maximum possible Pearson correlation coefficient of ~0.6, suggesting moderate correlation between Quaternary and GPS-derived slip rates for some faults (e.g., Kunlun and Longmen Shan faults). Faults with poorly correlated Quaternary and GPS-derived slip rates were identified and dating methods used for the Quaternary slip rates were examined. Results indicate that a poor correlation between Quaternary and GPS-derived slip rates exist for the Karakorum and Chaman faults. Large differences between Quaternary and GPS slip rates for these faults appear to be connected to qualitative dating of landforms used in the estimation of the Quaternary slip rates and errors in the geomorphic and structural reconstruction of offset landforms (e.g., offset terrace riser reconstructions for Altyn Tagh fault

  10. Artificial reef evaluation capabilities of Florida counties

    OpenAIRE

    Halusky, Joseph G.; Antonini, Gustavo A.; Seaman, William

    1993-01-01

    Florida's coastal county artificial reef sampling and data management programs are surveyed in this report. The survey describes the county level capability for artificial reef documentation and performance assessment based on their needs, interests, organizational structure and "in-situ" data collection and data management techniques. The. primary purpose of this study is to describe what staffing, training, techniques, organizational procedures and equipment are used by the c...

  11. Quaternary alluvial stratigraphy and palaeoclimatic reconstruction at the Thar margin

    DEFF Research Database (Denmark)

    Jain, M.; Tandon, S.K.

    2003-01-01

    Quaternary alluvial record at the Thar desert margin has been examined using the exposed succession along Mahudi, Sabarmati river, Western India. Different alluvial facies, their associations and granulometry have been studied for palaeoenvironmental reconstruction. Clay mineral indices smectite/...

  12. Potentiometric studies on quaternary complexes of dioxouranium(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Vinod; Chaturvedi, G K [Agra Coll., (India). Chemical Laboratories

    1979-10-01

    The formation of quaternary complexes of dioxouranium(VI) with three different organic acids (OX, MALN and SA, SSA, TAR or TMA) has been inferred from the potentiometric studies. The formation constants for the resulting triligand complexes have been evaluated.

  13. Macroalgae in the coral reefs of Eilat (Gulf of Aqaba, Red Sea) as a possible indicator of reef degradation

    International Nuclear Information System (INIS)

    Bahartan, Karnit; Zibdah, Mohammad; Ahmed, Yousef; Israel, Alvaro; Brickner, Itzchak; Abelson, Avigdor

    2010-01-01

    The current state of health of the coral reefs in the northern Gulf of Aqaba (Red Sea), notably the Eilat reefs, is under debate regarding both their exact condition and the causes of degradation. A dearth of earlier data and unequivocal reliable indices are the major problems hinder a clear understanding of the reef state. Our research objective was to examine coral-algal dynamics as a potential cause and an indication of reef degradation. The community structure of stony corals and algae along the northern Gulf of Aqaba reveal non-seasonal turf algae dominancy in the shallow Eilat reefs (up to 72%), while the proximate Aqaba reefs present negligible turf cover (<6%). We believe that turf dominancy can indicate degradation in these reefs, based on the reduction in essential reef components followed by proliferation of perennial turf algae. Our findings provide further evidence for the severe state of the Eilat coral reefs.

  14. Impacts of Artificial Reefs on Surrounding Ecosystems

    Science.gov (United States)

    Manoukian, Sarine

    Artificial reefs are becoming a popular biological and management component in shallow water environments characterized by soft seabed, representing both important marine habitats and tools to manage coastal fisheries and resources. An artificial reef in the marine environment acts as an open system with exchange of material and energy, altering the physical and biological characteristics of the surrounding area. Reef stability will depend on the balance of scour, settlement, and burial resulting from ocean conditions over time. Because of the unstable nature of sediments, they require a detailed and systematic investigation. Acoustic systems like high-frequency multibeam sonar are efficient tools in monitoring the environmental evolution around artificial reefs, whereas water turbidity can limit visual dive and ROV inspections. A high-frequency multibeam echo sounder offers the potential of detecting fine-scale distribution of reef units, providing an unprecedented level of resolution, coverage, and spatial definition. How do artificial reefs change over time in relation to the coastal processes? How accurately does multibeam technology map different typologies of artificial modules of known size and shape? How do artificial reefs affect fish school behavior? What are the limitations of multibeam technology for investigating fish school distribution as well as spatial and temporal changes? This study addresses the above questions and presents results of a new approach for artificial reef seafloor mapping over time, based upon an integrated analysis of multibeam swath bathymetry data and geoscientific information (backscatter data analysis, SCUBA observations, physical oceanographic data, and previous findings on the geology and sedimentation processes, integrated with unpublished data) from Senigallia artificial reef, northwestern Adriatic Sea (Italy) and St. Petersburg Beach Reef, west-central Florida continental shelf. A new approach for observation of fish

  15. Coral reefs and the World Bank.

    Science.gov (United States)

    Hatziolos, M

    1997-01-01

    The World Bank¿s involvement in coral reef conservation is part of a larger effort to promote the sound management of coastal and marine resources. This involves three major thrusts: partnerships, investments, networks and knowledge. As an initial partner and early supporter of the International Coral Reef Initiative (ICRI), the Bank serves as the executive planning committee of ICRI. In partnership with the World Conservation Union and the Great Barrier Reef Marine Park Authority, the Bank promotes the efforts towards the establishment and maintenance of a globally representative system of marine protected areas. In addition, the Bank invested over $120 million in coral reef rehabilitation and protection programs in several countries. Furthermore, the Bank developed a ¿Knowledge Bank¿ that would market ideas and knowledge to its clients along with investment projects. This aimed to put the best global knowledge on environmentally sustainable development in the hands of its staff and clients. During the celebration of 1997, as the International Year of the Reef, the Bank planned to cosponsor an associated event that would highlight the significance of coral reefs and encourage immediate action to halt their degradation to conserve this unique ecosystem.

  16. Caribbean Reef Response to Plio-Pleistocene Climate Change: Results of the Dominican Republic Drilling Project (DRDP)

    Science.gov (United States)

    Klaus, J.; McNeill, D. F.; Diaz, V.; Swart, P. K.; Pourmand, A.

    2014-12-01

    Caribbean reefs changed profoundly in taxonomic composition, diversity, and dominance structure during late Pliocene and Pleistocene climatic change. These changes coincide with protracted climatic deterioration and cooling between 2.0 to 0.8 Ma, and the onset of high amplitude sea-level fluctuations ~400 ka. The Dominican Republic Drilling Project (DRDP) was initiated to determine how climate change and global high-amplitude sea level changes influenced depositional patterns in Pliocene to Recent reef systems of the Caribbean. A transect of 7 core borings (~700 m total depth) were collected along the southern coast of the DR. New age constraints based on U/Th geochronometry and radiogenic Sr isotopes, combined with depositional lithofacies, faunal indicators, and stable isotope profiles have allowed us to correlate between wells and define the internal anatomy and stratal geometry of the individual reef sigmoids and sigmoid sets. Faunal records suggest most extinction occurred prior to ~1 Ma. Following this extinction, fringing reef margins of the Caribbean display a characteristic zonation in which Acropora palmata dominates shallow high-energy reef crests and Acropora cervicornis calmer fore-reef slopes and backreef lagoons. The dominance of acroporids across this zonation has been attributed to growth rates 5-100 times faster than other corals.

  17. Loss of an ecological baseline through the eradication of oyster reefs from coastal ecosystems and human memory.

    Science.gov (United States)

    Alleway, Heidi K; Connell, Sean D

    2015-06-01

    Oyster reefs form over extensive areas and the diversity and productivity of sheltered coasts depend on them. Due to the relatively recent population growth of coastal settlements in Australia, we were able to evaluate the collapse and extirpation of native oyster reefs (Ostrea angasi) over the course of a commercial fishery. We used historical records to quantify commercial catch of O. angasi in southern Australia from early colonization, around 1836, to some of the last recorded catches in 1944 and used our estimates of catch and effort to map their past distribution and assess oyster abundance over 180 years. Significant declines in catch and effort occurred from 1886 to 1946 and no native oyster reefs occur today, but historically oyster reefs extended across more than 1,500 km of coastline. That oyster reefs were characteristic of much of the coastline of South Australia from 1836 to 1910 appears not to be known because there is no contemporary consideration of their ecological and economic value. Based on the concept of a shifted baseline, we consider this contemporary state to reflect a collective, intergenerational amnesia. Our model of generational amnesia accounts for differences in intergenerational expectations of food, economic value, and ecosystem services of nearshore areas. An ecological system that once surrounded much of the coast and possibly the past presence of oyster reefs altogether may be forgotten and could not only undermine progress towards their recovery, but also reduce our expectations of these coastal ecosystems. © 2015 Society for Conservation Biology.

  18. Formation Mechanisms for Spur and Groove Features on Fringing Reefs

    Science.gov (United States)

    Bramante, J. F.; Ashton, A. D.; Perron, J. T.

    2016-12-01

    Spur and groove systems (SAGs) are ubiquitous morphological features found on fore-reef slopes globally. SAGs consist of parallel, roughly shore-normal ridges of actively growing coral and coralline algae (spurs) separated by offshore-sloping depressions typically carpeted by a veneer of sediment (grooves). Although anecdotal observations and recent statistical analyses have reported correlations between wave exposure and the distribution of SAGs on fore-reef slopes, the physical mechanisms driving SAG formation remain poorly understood. For example, there remains significant debate regarding the importance of coral growth versus bed erosion for SAG formation. Here we investigate a hypothesis that SAG formation is controlled by feedbacks between sediment production and diffusion and coral growth. Using linear stability analysis, we find that sediment production, coral growth, and the feedbacks between them are unable to produce stable periodic structures without a sediment sink. However, if incipient grooves act as conduits for sediment transport offshore, a positive feedback can develop as the groove bed erodes through wave-driven abrasion during offshore transport. Eventually a negative feedback slows groove deepening when the groove bed is armored by sediment, and the groove bed relaxes to a sediment-veneered equilibrium profile analogous to sediment-rich shorefaces. To test this hypothesis, we apply a numerical model that incorporates coral growth and sediment production, sediment diffusion, non-linear wave-driven abrasion, and sediment advection offshore. This model produces the periodic, linear features characteristic of SAG morphology. The relative magnitude of growth, production, diffusion, abrasion, and advection rates affect periodic spacing or wavelength of the modeled SAGs. Finally, we evaluate the ability of the model to replicate geographical variability in SAG characteristics using previously published datasets and reanalysis wave data.

  19. Spectroscopic markers of the TR quaternary transition in human hemoglobin.

    Science.gov (United States)

    Schirò, Giorgio; Cammarata, Marco; Levantino, Matteo; Cupane, Antonio

    2005-04-01

    In this work, we use a sol-gel protocol to trap and compare the R and T quaternary states of both the deoxygenated (deoxyHb) and carbonmonoxide (HbCO) derivatives of human hemoglobin. The near infrared optical absorption band III and the infrared CO stretching band are used to detect the effect of quaternary structure on the spectral properties of deoxyHb and HbCO; comparison with myoglobin allows for an assessment of tertiary and quaternary contributions to the measured band shifts. The RT transition is shown to cause a blue shift of the band III by approximately 35 cm(-1) for deoxyHb and a red shift of the CO stretching band by only approximately 0.3 cm(-1) for HbCO. This clearly shows that quaternary structure changes are transmitted to the heme pocket and that effects on deoxyHb are much larger than on HbCO, at least as far as the band energies are concerned. Experiments performed in the ample temperature interval of 300-10K show that the above quaternary structure effects are "static" and do not influence the dynamic properties of the heme pocket, at least as probed by the temperature dependence of band III and of the CO stretching band. The availability of quaternary structure sensitive spectroscopic markers and the quantitative measurement of the quaternary structure contribution to band shifts will be of considerable help in the analysis of flash-photolysis experiments on hemoglobin. Moreover, it will enable one to characterize the dynamic properties of functionally relevant hemoglobin intermediates and to study the kinetics of both the T-->R and R-->T quaternary transitions through time-resolved spectroscopy.

  20. EOWD-Eco Open Water Diver- New Divers License needed? Effect of Intensive SCUBA Diving on Fringing Reefs of the Northern Red Sea

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald

    2006-01-01

    Intensive recreational SCUBA diving threatens coral reef diversity and health [1]. Two anthropogenic factors contributing to coral reef decline are sedimentation [4] and damage from snorklers and SCUBA divers [1]. Physical contact of divers (fins, hands, equipment) and increased sedimentation...... are two major effects diredtly caused by SCUBA diving. Diver damage varies depending on the growth form of corals present. Branching corals appear to sustain most of the breaks although they are most affected [5]. As coral reef tourism continues to grow, the need to quantify, manage and mitigate...

  1. A Quaternary Geomagnetic Instability Time Scale

    Science.gov (United States)

    Singer, B. S.

    2013-12-01

    Reversals and excursions of Earth's geomagnetic field create marker horizons that are readily detected in sedimentary and volcanic rocks worldwide. An accurate and precise chronology of these geomagnetic field instabilities is fundamental to understanding several aspects of Quaternary climate, dynamo processes, and surface processes. For example, stratigraphic correlation between marine sediment and polar ice records of climate change across the cryospheres benefits from a highly resolved record of reversals and excursions. The temporal patterns of dynamo behavior may reflect physical interactions between the molten outer core and the solid inner core or lowermost mantle. These interactions may control reversal frequency and shape the weak magnetic fields that arise during successive dynamo instabilities. Moreover, weakening of the axial dipole during reversals and excursions enhances the production of cosmogenic isotopes that are used in sediment and ice core stratigraphy and surface exposure dating. The Geomagnetic Instability Time Scale (GITS) is based on the direct dating of transitional polarity states recorded by lava flows using the 40Ar/39Ar method, in parallel with astrochronologic age models of marine sediments in which O isotope and magnetic records have been obtained. A review of data from Quaternary lava flows and sediments yields a GITS comprising 10 polarity reversals and 27 excursions during the past 2.6 million years. Nine of the ten reversals bounding chrons and subchrons are associated with 40Ar/39Ar ages of transitionally-magnetized lava flows. The tenth, the Guass-Matuyama chron boundary, is tightly bracketed by 40Ar/39Ar dated ash deposits. Of the 27 well-documented excursions, 14 occurred during the Matuyama chron and 13 during the Brunhes chron; 19 have been dated directly using the 40Ar/39Ar method on transitionally-magnetized volcanic rocks and form the backbone of the GITS. Excursions are clearly not the rare phenomena once thought

  2. Coral reef sedimentation on Rodrigues and the Western Indian Ocean and its impact on the carbon cycle.

    Science.gov (United States)

    Rees, Siwan A; Opdyke, Bradley N; Wilson, Paul A; Fifield, L Keith

    2005-01-15

    Coral reefs in the southwest Indian Ocean cover an area of ca. 18,530 km2 compared with a global reef area of nearly 300,000 km2. These regions are important as fishing grounds, tourist attractions and as a significant component of the global carbon cycle. The mass of calcium carbonate stored within Holocene neritic sediments is a number that we are only now beginning to quantify with any confidence, in stark contrast to the mass and sedimentation rates associated with pelagic calcium carbonate, which have been relatively well defined for decades. We report new data that demonstrate that the reefs at Rodrigues, like those at Reunion and Mauritius, only reached a mature state (reached sea level) by 2-3 ka: thousands of years later than most of the reefs in the Australasian region. Yet field observations show that the large lagoon at Rodrigues is already completely full of carbonate detritus (typical lagoon depth less than 1 m at low spring tide). The presence of aeolian dunes at Rodrigues indicates periodic exposure of past lagoons throughout the Pleistocene. The absence of elevated Pleistocene reef deposits on the island indicates that the island has not been uplifted. Most Holocene reefs are between 15 and 20 m in thickness and those in the southwest Indian Ocean appear to be consistent with this observation. We support the view that the CO2 flux associated with coral-reef growth acts as a climate change amplifier during deglaciation, adding CO2 to a warming world. southwest Indian Ocean reefs could have added 7-10% to this global flux during the Holocene.

  3. Influence of depth on sex-specific energy allocation patterns in a tropical reef fish

    Science.gov (United States)

    Hoey, J.; McCormick, M. I.; Hoey, A. S.

    2007-09-01

    The effect of depth on the distribution and sex-specific energy allocation patterns of a common coral reef fish, Chrysiptera rollandi (Pomacentridae), was investigated using depth-stratified collections over a broad depth range (5-39 m) and a translocation experiment. C. rollandi consistently selected rubble habitats at each depth, however abundance patterns did not reflect the availability of the preferred microhabitat suggesting a preference for depth as well as microhabitat. Reproductive investment (gonado-somatic index), energy stores (liver cell density and hepatocyte vacuolation), and overall body condition (hepato-somatic index and Fulton’s K) of female fish varied significantly among depths and among the three reefs sampled. Male conspecifics displayed no variation between depth or reef. Depth influenced growth dynamics, with faster initial growth rates and smaller mean asymptotic lengths with decreasing depth. In female fish, relative gonad weight and overall body condition (Fulton’s K and hepato-somatic index) were generally higher in shallower depths (≤10 m). Hepatic lipid storage was highest at the deepest sites sampled on each reef, whereas hepatic glycogen stores tended to decrease with depth. Depth was found to influence energy allocation dynamics in C. rollandi. While it is unclear what processes directly influenced the depth-related patterns in energy allocation, this study shows that individuals across a broad depth gradient are not all in the same physiological state and may contribute differentially to the population reproductive output.

  4. Distribution and structure of the southernmost Caribbean coral reefs: golfo de Urabá, Colombia

    Directory of Open Access Journals (Sweden)

    J. M. Díaz

    2000-09-01

    Full Text Available The Gulf of Urabá represents the southernmost portion of the Caribbean Sea. Due to the large amounts of sediment and freshwater discharged by the Atrato river and several minor streams, water conditions in the area are far from being optimal for coral settlement and growth. However, fringing and patch reefs are developed along the rocky shores of the northwest margin of the Gulf. Based on field observations performed at 44 sites (12 of them assessed quantitatively, interpretation of air photography of the area and depth profiles, the distribution, structure and zonation of the reefs are described. Classification analysis of the 12 sample sites yielded four coral assemblages: Diploria strigosa, crustose algae, Siderastrea siderea, Agaricia spp., and mixed massive corals. Other two assemblages, dominated respectively by Millepora complanata and thickets of Acropora palmata were noticed during reconnaissance dives. The distribution of these zones within the reef seems likely to be mainly controlled by wave exposure, bottom topography, sedimentation, and light penetration. Reef development, coral diversity and live coral cover increase along the coast in a SE-NW direction, with an evident maximum near to the cove of Sapzurro, suggesting an overall improvement of conditions for coral growth and settlement in that direction. A total of 33 species of hard corals were recorded during the survey. It is apparent that the live coral cover, particularly of foliose and branching species, has notably declined recently.

  5. Identification and prevalence of coral diseases on three Western Indian Ocean coral reefs.

    Science.gov (United States)

    Séré, Mathieu G; Chabanet, Pascale; Turquet, Jean; Quod, Jean-Pascal; Schleyer, Michael H

    2015-06-03

    Coral diseases have caused a substantial decline in the biodiversity and abundance of reef-building corals. To date, more than 30 distinct diseases of scleractinian corals have been reported, which cause progressive tissue loss and/or affect coral growth, reproductive capacity, recruitment, species diversity and the abundance of reef-associated organisms. While coral disease research has increased over the last 4 decades, very little is known about coral diseases in the Western Indian Ocean. Surveys conducted at multiple sites in Reunion, South Africa and Mayotte between August 2010 and June 2012 revealed the presence of 6 main coral diseases: black band disease (BBD), white syndrome (WS), pink line syndrome (PLS), growth anomalies (GA), skeleton eroding band (SEB) and Porites white patch syndrome (PWPS). Overall, disease prevalence was higher in Reunion (7.5 ± 2.2%; mean ± SE) compared to South Africa (3.9 ± 0.8%) and Mayotte (2.7 ± 0.3%). Across locations, Acropora and Porites were the genera most susceptible to disease. Spatial variability was detected in both Reunion and South Africa, with BBD and WS more prevalent on shallow than deep reefs. There was also evidence of seasonality in 2 diseases: the prevalence of BBD and WS was higher in summer than winter. This was the first study to investigate the ecology of coral diseases, providing both qualitative and quantitative data, on Western Indian Ocean reefs, and surveys should be expanded to confirm these patterns.

  6. Widespread prevalence of cryptic Symbiodinium D in the key Caribbean reef builder, Orbicella annularis

    Science.gov (United States)

    Kennedy, Emma V.; Foster, Nicola L.; Mumby, Peter J.; Stevens, Jamie R.

    2015-06-01

    Symbiodinium D, a relatively rare clade of algal endosymbiont with a global distribution, has attracted interest as some of its sub-cladal types induce increased thermal tolerance and associated trade-offs, including reduced growth rate in its coral hosts. Members of Symbiodinium D are increasingly reported to comprise low-abundance `cryptic' (30 % of corals per site found to harbour the symbiont. When the same samples were analysed using the conventional screening technique, denaturing gradient gel electrophoresis, Symbiodinium D1 was only detected in 12 populations and appeared to be hosted by agreement with other reported low prevalence/absences in O. annularis). Cryptic Symbiodinium D1 showed a mainly uniform distribution across the wider Caribbean region, although significantly more Mesoamerican Barrier Reef corals hosted cryptic Symbiodinium D1 than might be expected by chance, possibly as a consequence of intense warming in the region in 1998. Widespread prevalence of thermally tolerant Symbiodinium in O. annularis may potentially reflect a capacity for the coral to temporarily respond to warming events through symbiont shuffling. However, association with reduced coral calcification means that the ubiquitous nature of Symbiodinium D1 in O. annularis populations is unlikely to prevent long-term declines in reef health, at a time when maintaining reef growth is vital to sustain reef ecosystem function.

  7. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    Energy Technology Data Exchange (ETDEWEB)

    Dmochowska, Barbara [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Piosik, Jacek; Woziwodzka, Anna [Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk (Poland); Sikora, Karol; Wisniewski, Andrzej [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Wegrzyn, Grzegorz, E-mail: wegrzyn@biotech.univ.gda.pl [Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk (Poland)

    2011-10-15

    Highlights: {yields} A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. {yields} The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. {yields} The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. {yields} We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  8. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    International Nuclear Information System (INIS)

    Dmochowska, Barbara; Piosik, Jacek; Woziwodzka, Anna; Sikora, Karol; Wisniewski, Andrzej; Wegrzyn, Grzegorz

    2011-01-01

    Highlights: → A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. → The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. → The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. → We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  9. Length-weight relationships of coral reef fishes from the Alacran Reef, Yucatan, Mexico

    OpenAIRE

    Gonzalez-Gandara, C.; Perez-Diaz, E.; Santos-Rodriguez, L.; Arias-Gonzalez, J.E.

    2003-01-01

    Length-weight relationships were computed for 42 species of coral reef fishes from 14 families from the Alacran Reef (Yucatan, Mexico). A total of 1 892 individuals was used for this purpose. The fish species were caught by different fishing techniques such as fishhooks, harpoons, gill and trawl nets. The sampling period was from March 1998 to January 2000.

  10. Microbial to reef scale interactions between the reef-building coral Montastraea annularis and benthic algae

    NARCIS (Netherlands)

    Barott, K.L.; Rodriguez-Mueller, B; Youle, M.; Marhaver, K.L.; Vermeij, M.J.A.; Smith, J.E.; Rohwer, F.L.

    2012-01-01

    Competition between reef-building corals and benthic algae is of key importance for reef dynamics. These interactions occur on many spatial scales, ranging from chemical to regional. Using microprobes, 16S rDNA pyrosequencing and underwater surveys, we examined the interactions between the

  11. Oyster Reef Communities in the Chesapeake Bay: A Brief Primer. VORTEX: Virginia's Oyster Reef Teaching EXperience.

    Science.gov (United States)

    Harding, Juliana M.; Mann, Roger; Clark, Vicki P.

    This document introduces Virginia's Oyster Reef Teaching EXperience (VORTEX), which is an interdisciplinary program focusing on the importance of oyster reef communities in the Chesapeake Bay ecosystem. The VORTEX program uses field and laboratory experience supported by multimedia instruction. This document presents an overview on the biology of…

  12. Cumulative Human Impacts on Coral Reefs: Assessing Risk and Management Implications for Brazilian Coral Reefs

    Directory of Open Access Journals (Sweden)

    Rafael A. Magris

    2018-04-01

    Full Text Available Effective management of coral reefs requires strategies tailored to cope with cumulative disturbances from human activities. In Brazil, where coral reefs are a priority for conservation, intensifying threats from local and global stressors are of paramount concern to management agencies. Using a cumulative impact assessment approach, our goal was to inform management actions for coral reefs in Brazil by assessing their exposure to multiple stressors (fishing, land-based activities, coastal development, mining, aquaculture, shipping, and global warming. We calculated an index of the risk to cumulative impacts: (i assuming uniform sensitivity of coral reefs to stressors; and (ii using impact weights to reflect varying tolerance levels of coral reefs to each stressor. We also predicted the index in both the presence and absence of global warming. We found that 16% and 37% of coral reefs had high to very high risk of cumulative impacts, without and with information on sensitivity respectively, and 42% of reefs had low risk to cumulative impacts from both local and global stressors. Our outputs are the first comprehensive spatial dataset of cumulative impact on coral reefs in Brazil, and show that areas requiring attention mostly corresponded to those closer to population centres. We demonstrate how the relationships between risks from local and global stressors can be used to derive strategic management actions.

  13. Coral mortality in reefs: The cause and effect; A central concern for reef monitoring

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.

    stream_size 4 stream_content_type text/plain stream_name Region_Workshop_Conserv_Sustain_Mgmt_Coral_Reefs_1997_C83.pdf.txt stream_source_info Region_Workshop_Conserv_Sustain_Mgmt_Coral_Reefs_1997_C83.pdf.txt Content-Encoding ISO-8859...

  14. The effect of local hydrodynamics on the spatial extent and morphology of cold-water coral habitats at Tisler Reef, Norway

    Science.gov (United States)

    De Clippele, L. H.; Huvenne, V. A. I.; Orejas, C.; Lundälv, T.; Fox, A.; Hennige, S. J.; Roberts, J. M.

    2018-03-01

    This study demonstrates how cold-water coral morphology and habitat distribution are shaped by local hydrodynamics, using high-definition video from Tisler Reef, an inshore reef in Norway. A total of 334 video frames collected on the north-west (NW) and south-east (SE) side of the reef were investigated for Lophelia pertusa coral cover and morphology and for the cover of the associated sponges Mycale lingua and Geodia sp. Our results showed that the SE side was a better habitat for L. pertusa (including live and dead colonies). Low cover of Geodia sp. was found on both sides of Tisler Reef. In contrast, Mycale lingua had higher percentage cover, especially on the NW side of the reef. Bush-shaped colonies of L. pertusa with elongated branches were the most abundant coral morphology on Tisler Reef. The highest abundance and density of this morphology were found on the SE side of the reef, while a higher proportion of cauliflower-shaped corals with short branches were found on the NW side. The proportion of very small L. pertusa colonies was also significantly higher on the SE side of the reef. The patterns in coral spatial distribution and morphology were related to local hydrodynamics—there were more frequent periods of downwelling currents on the SE side—and to the availability of suitable settling substrates. These factors make the SE region of Tisler Reef more suitable for coral growth. Understanding the impact of local hydrodynamics on the spatial extent and morphology of coral, and their relation to associated organisms such as sponges, is key to understanding the past and future development of the reef.

  15. Facilitation in Caribbean coral reefs: high densities of staghorn coral foster greater coral condition and reef fish composition.

    Science.gov (United States)

    Huntington, Brittany E; Miller, Margaret W; Pausch, Rachel; Richter, Lee

    2017-05-01

    Recovery of the threatened staghorn coral (Acropora cervicornis) is posited to play a key role in Caribbean reef resilience. At four Caribbean locations (including one restored and three extant populations), we quantified characteristics of contemporary staghorn coral across increasing conspecific densities, and investigated a hypothesis of facilitation between staghorn coral and reef fishes. High staghorn densities in the Dry Tortugas exhibited significantly less partial mortality, higher branch growth, and supported greater fish abundances compared to lower densities within the same population. In contrast, partial mortality, branch growth, and fish community composition did not vary with staghorn density at the three other study locations where staghorn densities were lower overall. This suggests that density-dependent effects between the coral and fish community may only manifest at high staghorn densities. We then evaluated one facilitative mechanism for such density-dependence, whereby abundant fishes sheltering in dense staghorn aggregations deliver nutrients back to the coral, fueling faster coral growth, thereby creating more fish habitat. Indeed, dense staghorn aggregations within the Dry Tortugas exhibited significantly higher growth rates, tissue nitrogen, and zooxanthellae densities than sparse aggregations. Similarly, higher tissue nitrogen was induced in a macroalgae bioassay outplanted into the same dense and sparse aggregations, confirming greater bioavailability of nutrients at high staghorn densities. Our findings inform staghorn restoration efforts, suggesting that the most effective targets may be higher coral densities than previously thought. These coral-dense aggregations may reap the benefits of positive facilitation between the staghorn and fish community, favoring the growth and survivorship of this threatened species.

  16. Soundscapes from a Tropical Eastern Pacific reef and a Caribbean Sea reef

    Science.gov (United States)

    Staaterman, E.; Rice, A. N.; Mann, D. A.; Paris, C. B.

    2013-06-01

    Underwater soundscapes vary due to the abiotic and biological components of the habitat. We quantitatively characterized the acoustic environments of two coral reef habitats, one in the Tropical Eastern Pacific (Panama) and one in the Caribbean (Florida Keys), over 2-day recording durations in July 2011. We examined the frequency distribution, temporal variability, and biological patterns of sound production and found clear differences. The Pacific reef exhibited clear biological patterns and high temporal variability, such as the onset of snapping shrimp noise at night, as well as a 400-Hz daytime band likely produced by damselfish. In contrast, the Caribbean reef had high sound levels in the lowest frequencies, but lacked clear temporal patterns. We suggest that acoustic measures are an important element to include in reef monitoring programs, as the acoustic environment plays an important role in the ecology of reef organisms at multiple life-history stages.

  17. Environmental controls on daytime net community calcification on a Red Sea reef flat

    KAUST Repository

    Bernstein, W. N.

    2016-01-23

    Coral growth and carbonate accumulation form the foundation of the coral reef ecosystem. Changes in environmental conditions due to coastal development, climate change, and ocean acidification may pose a threat to net carbonate production in the near future. Controlled laboratory studies demonstrate that calcification by corals and coralline algae is sensitive to changes in aragonite saturation state (Ωa), as well as temperature, light, and nutrition. Studies also show that the dissolution rate of carbonate substrates is impacted by changes in carbonate chemistry. The sensitivity of coral reefs to these parameters must be confirmed and quantified in the natural environment in order to predict how coral reefs will respond to local and global changes, particularly ocean acidification. We estimated the daytime hourly net community metabolic rates, both net community calcification (NCC) and net community productivity (NCP), at Sheltered Reef, an offshore platform reef in the central Red Sea. Average NCC was 8 ± 3 mmol m−2 h−1 in December 2010 and 11 ± 1 mmol m−2 h−1 in May 2011, and NCP was 21 ± 7 mmol m−2 h−1 in December 2010 and 44 ± 4 mmol m−2 h−1 in May 2011. We also monitored a suite of physical and chemical properties to help relate the rates at Sheltered Reef to published rates from other sites. While previous research shows that short-term field studies investigating the NCC–Ωa relationship have differing results due to confounding factors, it is important to continue estimating NCC in different places, seasons, and years, in order to monitor changes in NCC versus Ω in space and time, and to ultimately resolve a broader understanding of this relationship.

  18. New quaternary ammonium salts based decontaminants

    Directory of Open Access Journals (Sweden)

    Diana M. Popescu

    2014-06-01

    Full Text Available Decontamination after terrorist attacks or industrial accidents with biological and/or chemical agents („bio-chem“ must be fast and efficient, in order to reduce the number of victims and to eliminate the consequent damages. The decontamination of living biological agents (bacteria, viruses or nonliving ones (toxins, regulators and toxic chemicals could be accomplished by reactions of hydrolysis in various experimental conditions, in particular in alkaline medium, reactions with amines or ammonia, alcohols, phenols etc. and by their transformation into less toxic degradation products. “Bio-chem” intentional or unintentional contamination is a real risk, towards which an effective management must be available to prevent and control it. Decontamination is an essential measure to protect the personnel and the environment. Synthesis and testing of new „bio-chem“ decontaminants, based on quaternary ammonium salts, complete the arsenal of protection against chemical and biological agents. The most effective selected substances could be produced and used for decontamination in accordance with legal procedures

  19. Late Quaternary history of the Atacama Desert

    Science.gov (United States)

    Latorre, Claudio; Betancourt, Julio L.; Rech, Jason A.; Quade, Jay; Holmgren, Camille; Placzek, Christa; Maldonado, Antonio; Vuille, Mathias; Rylander, Kate A.; Smith, Mike; Hesse, Paul

    2005-01-01

    Of the major subtropical deserts found in the Southern Hemisphere, the Atacama Desert is the driest. Throughout the Quaternary, the most pervasive climatic influence on the desert has been millennial-scale changes in the frequency and seasonality of the scant rainfall, and associated shifts in plant and animal distributions with elevation along the eastern margin of the desert. Over the past six years, we have mapped modern vegetation gradients and developed a number of palaeoenvironmental records, including vegetation histories from fossil rodent middens, groundwater levels from wetland (spring) deposits, and lake levels from shoreline evidence, along a 1200-kilometre transect (16–26°S) in the Atacama Desert. A strength of this palaeoclimate transect has been the ability to apply the same methodologies across broad elevational, latitudinal, climatic, vegetation and hydrological gradients. We are using this transect to reconstruct the histories of key components of the South American tropical (summer) and extratropical (winter) rainfall belts, precisely at those elevations where average annual rainfall wanes to zero. The focus has been on the transition from sparse, shrubby vegetation (known as the prepuna) into absolute desert, an expansive hyperarid terrain that extends from just above the coastal fog zone (approximately 800 metres) to more than 3500 metres in the most arid sectors in the southern Atacama.

  20. Methane hydrates in quaternary climate change

    International Nuclear Information System (INIS)

    Kennett, J. P.; Hill, T. M.; Behl, R. J.

    2005-01-01

    The hydrate reservoir in marine sediments is known to contain a large volume of exchangeable carbon stored as solid methane hydrate and associated free gas. This reservoir has been shown to be potentially unstable in response to changing intermediate water temperature and sea level (pressure). Evidence continues to grow for past episodes of major methane release at times of climatic warming. Yet few studies of late Quaternary climate change include methane hydrates as an integral part of the global climate system, in spite of the largest known oscillations at this time in sea level and upper ocean temperature changes for the Cenozoic or earlier, conditions that favor instability of the methane hydrate reservoir. Abrupt increases in atmospheric methane recorded in polar ice cores are widely believed to have resulted, not from ocean-floor methane degassing, but instead from continental wetland activation, a hypothesis thus far unsupported by geological data. Furthermore, as part of this Wetland Methane Hypothesis, the abrupt methane increases have been seen as a response to climatic warming rather than contributing significantly to the change. An alternative view (formulated as the Clathrate Gun Hypothesis) is that the speed, magnitude and timing of abrupt climate change in the recent geologic past are consistent with the process of major degassing of methane hydrates. We summarize aspects of this hypothesis here and needs to test this hypothesis. (Author)

  1. Does reef architectural complexity influence resource availability for a large reef-dwelling invertebrate?

    Science.gov (United States)

    Lozano-Álvarez, Enrique; Luviano-Aparicio, Nelia; Negrete-Soto, Fernando; Barradas-Ortiz, Cecilia; Aguíñiga-García, Sergio; Morillo-Velarde, Piedad S.; Álvarez-Filip, Lorenzo; Briones-Fourzán, Patricia

    2017-10-01

    In coral reefs, loss of architectural complexity and its associated habitat degradation is expected to affect reef specialists in particular due to changes in resource availability. We explored whether these features could potentially affect populations of a large invertebrate, the spotted spiny lobster Panulirus guttatus, which is an obligate Caribbean coral reef-dweller with a limited home range. We selected two separate large coral reef patches in Puerto Morelos (Mexico) that differed significantly in structural complexity and level of degradation, as assessed via the rugosity index, habitat assessment score, and percent cover of various benthic components. On each reef, we estimated density of P. guttatus and sampled lobsters to analyze their stomach contents, three different condition indices, and stable isotopes (δ15N and δ13C) in muscle. Lobster density did not vary with reef, suggesting that available crevices in the less complex patch still provided adequate refuge to these lobsters. Lobsters consumed many food types, dominated by mollusks and crustaceans, but proportionally more crustaceans (herbivore crabs) in the less complex patch, which had more calcareous macroalgae and algal turf. Lobsters from both reefs had a similar condition (all three indices) and mean δ15N, suggesting a similar quality of diet between reefs related to their opportunistic feeding, but differed in mean δ13C values, reflecting the different carbon sources between reefs and providing indirect evidence of individuals of P. guttatus foraging exclusively over their home reef. Overall, we found no apparent effects of architectural complexity, at least to the degree observed in our less complex patch, on density, condition, or trophic level of P. guttatus.

  2. Reef odor: a wake up call for navigation in reef fish larvae.

    Directory of Open Access Journals (Sweden)

    Claire B Paris

    Full Text Available The behavior of reef fish larvae, equipped with a complex toolbox of sensory apparatus, has become a central issue in understanding their transport in the ocean. In this study pelagic reef fish larvae were monitored using an unmanned open-ocean tracking device, the drifting in-situ chamber (DISC, deployed sequentially in oceanic waters and in reef-born odor plumes propagating offshore with the ebb flow. A total of 83 larvae of two taxonomic groups of the families Pomacentridae and Apogonidae were observed in the two water masses around One Tree Island, southern Great Barrier Reef. The study provides the first in-situ evidence that pelagic reef fish larvae discriminate reef odor and respond by changing their swimming speed and direction. It concludes that reef fish larvae smell the presence of coral reefs from several kilometers offshore and this odor is a primary component of their navigational system and activates other directional sensory cues. The two families expressed differences in their response that could be adapted to maintain a position close to the reef. In particular, damselfish larvae embedded in the odor plume detected the location of the reef crest and swam westward and parallel to shore on both sides of the island. This study underlines the critical importance of in situ Lagrangian observations to provide unique information on larval fish behavioral decisions. From an ecological perspective the central role of olfactory signals in marine population connectivity raises concerns about the effects of pollution and acidification of oceans, which can alter chemical cues and olfactory responses.

  3. Spatial and tidal variation in food supply to shallow cold-water coral reefs of the Mingulay Reef complex (Outer Hebrides, Scotland)

    NARCIS (Netherlands)

    Duineveld, G.C.A.; Jeffreys, R.M.; Lavaleye, M.S.S.; Davies, A.J.; Bergman, M.J.N.; Watmough, T.; Witbaard, R.

    2012-01-01

    The finding of a previously undescribed cold-water coral reef (Banana Reef) in the Scottish Mingulay reef complex, with denser coverage of living Lophelia pertusa than the principal Mingulay 1 Reef, was the incentive for a comparative study of the food supply to the 2 reefs. Suspended particulate

  4. Hyperspectral remote sensing of wild oyster reefs

    Science.gov (United States)

    Le Bris, Anthony; Rosa, Philippe; Lerouxel, Astrid; Cognie, Bruno; Gernez, Pierre; Launeau, Patrick; Robin, Marc; Barillé, Laurent

    2016-04-01

    The invasion of the wild oyster Crassostrea gigas along the western European Atlantic coast has generated changes in the structure and functioning of intertidal ecosystems. Considered as an invasive species and a trophic competitor of the cultivated conspecific oyster, it is now seen as a resource by oyster farmers following recurrent mass summer mortalities of oyster spat since 2008. Spatial distribution maps of wild oyster reefs are required by local authorities to help define management strategies. In this work, visible-near infrared (VNIR) hyperspectral and multispectral remote sensing was investigated to map two contrasted intertidal reef structures: clusters of vertical oysters building three-dimensional dense reefs in muddy areas and oysters growing horizontally creating large flat reefs in rocky areas. A spectral library, collected in situ for various conditions with an ASD spectroradiometer, was used to run Spectral Angle Mapper classifications on airborne data obtained with an HySpex sensor (160 spectral bands) and SPOT satellite HRG multispectral data (3 spectral bands). With HySpex spectral/spatial resolution, horizontal oysters in the rocky area were correctly classified but the detection was less efficient for vertical oysters in muddy areas. Poor results were obtained with the multispectral image and from spatially or spectrally degraded HySpex data, it was clear that the spectral resolution was more important than the spatial resolution. In fact, there was a systematic mud deposition on shells of vertical oyster reefs explaining the misclassification of 30% of pixels recognized as mud or microphytobenthos. Spatial distribution maps of oyster reefs were coupled with in situ biomass measurements to illustrate the interest of a remote sensing product to provide stock estimations of wild oyster reefs to be exploited by oyster producers. This work highlights the interest of developing remote sensing techniques for aquaculture applications in coastal

  5. Coralline reefs classification in Banco Chinchorro, Mexico

    Science.gov (United States)

    Contreras-Silva, Ameris I.; López-Caloca, Alejandra A.

    2009-09-01

    The coralline reefs in Banco Chinchorro, Mexico, are part of the great reef belt of the western Atlantic. This reef complex is formed by an extensive coralline structure with great biological richness and diversity of species. These colonies are considered highly valuable ecologically, economically, socially and culturally, and they also inherently provide biological services. Fishing and scuba diving have been the main economic activities in this area for decades. However, in recent years, there has been a bleaching process and a decrease of the coral colonies in Quintana Roo, Mexico. This drop is caused mainly by the production activities performed in the oil platforms and the presence of hurricanes among other climatic events. The deterioration of the reef system can be analyzed synoptically using remote sensing. Thanks to this type of analysis, it is possible to have updated information of the reef conditions. In this paper, satellite imagery in Landsat TM and SPOT 5 is applied in the coralline reefs classification in the 1980- 2006 time period. Thus, an integral analysis of the optical components of the water surrounding the coralline reefs, such as on phytoplankton, sediments, yellow substance and even on the same water adjacent to the coral colonies, is performed. The use of a texture algorithm (Markov Random Field) was a key tool for their identification. This algorithm, does not limit itself to image segmentation, but also works on edge detection. In future work the multitemporal analysis of the results will determine the deterioration degree of these habitats and the conservation status of the coralline areas.

  6. Pacific Reef Assessment and Monitoring Program: Assessing and Monitoring Cryptic Reef Diversity of Colonizing Marine Invertebrates using Autonomous Reef Monitoring Structures (ARMS) Deployed at Coral Reef Sites across the U.S. Pacific from 2008 to 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To support a long-term program for sustainable management and conservation of coral reef ecosystems, from 2008, Autonomous Reef Monitoring Structures (ARMS) have...

  7. Biomass and Abundance of Herbivorous Fishes on Coral Reefs off ...

    African Journals Online (AJOL)

    effects of fishing intensity, reef geomorphology and benthic cover. Distance from the .... on herbivorous fish communities relevant to the proposed ... fragments, nearshore coastal fringing reefs ..... Over-fishing and coral bleaching pose the most ...

  8. National Coral Reef Monitoring Program: Assessing and Monitoring Cryptic Reef Diversity of Colonizing Marine Invertebrates using Autonomous Reef Monitoring Structure (ARMS) Deployed at Coral Reef Sites across the Pacific Remote Island Areas from 2011 to 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Autonomous Reef Monitoring Structures (ARMS) are used to assess and monitor cryptic reef diversity of colonizing marine invertebrates in the Hawaiian and Mariana...

  9. National Coral Reef Monitoring Program: Assessing and Monitoring Cryptic Reef Diversity of Colonizing Marine Invertebrates using Autonomous Reef Monitoring Structure (ARMS) Deployed at Coral Reef Sites across the Marianas Archipelago from 2011 to 2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Autonomous Reef Monitoring Structures (ARMS) are used to assess and monitor cryptic reef diversity of colonizing marine invertebrates in the Hawaiian and Mariana...

  10. National Coral Reef Monitoring Program: Assessing and Monitoring Cryptic Reef Diversity of Colonizing Marine Invertebrates using Autonomous Reef Monitoring Structure (ARMS) Deployed at Coral Reef Sites across the Hawaiian Archipelago from 2010 to 2016

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Autonomous Reef Monitoring Structures (ARMS) are used to assess and monitor cryptic reef diversity of colonizing marine invertebrates in the Hawaiian and Mariana...

  11. National Coral Reef Monitoring Program: Assessing and Monitoring Cryptic Reef Diversity of Colonizing Marine Invertebrates using Autonomous Reef Monitoring Structure (ARMS) Deployed at Coral Reef Sites across American Samoa from 2012 to 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Autonomous Reef Monitoring Structures (ARMS) are used to assess and monitor cryptic reef diversity of colonizing marine invertebrates in the Hawaiian and Mariana...

  12. 2015 Carbbean Reef Fish Survey (PC1505, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2015 Caribbean Reef Fish Survey were to assess relative abundance of reef fish species around the US Caribbean Islands, estimate length-frequency...

  13. SEAMAP Caribbean Reef Fish Survey (PC1202, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2012 SEAMAP Caribbean Reef Fish Survey were to assess relative abundance of reef fish species around the US Caribbean Islands, estimate...

  14. 2012 SEAMAP Reef Fish Survey (PC1201, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2012 SEAMAP Reef Fish Survey were to collect video data of reef fish on western Gulf of Mexico shelf-edge banks to facilitate assessments of...

  15. 2012 SEAMAP Reef Fish Survey (PC1201, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2012 SEAMAP Reef Fish Survey were to collect video data of reef fish on western Gulf of Mexico shelf-edge banks to facilitate assessments of...

  16. The exposure of the Great Barrier Reef to ocean acidification

    KAUST Repository

    Mongin, Mathieu; Baird, Mark E.; Tilbrook, Bronte; Matear, Richard J.; Lenton, Andrew; Herzfeld, Mike; Wild-Allen, Karen; Skerratt, Jenny; Margvelashvili, Nugzar; Robson, Barbara J.; Duarte, Carlos M.; Gustafsson, Malin S. M.; Ralph, Peter J.; Steven, Andrew D. L.

    2016-01-01

    The Great Barrier Reef (GBR) is founded on reef-building corals. Corals build their exoskeleton with aragonite, but ocean acidification is lowering the aragonite saturation state of seawater (Ωa). The downscaling of ocean acidification projections

  17. SEAMAP Caribbean Reef Fish Survey (PC1202, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2012 SEAMAP Caribbean Reef Fish Survey were to assess relative abundance of reef fish species around the US Caribbean Islands, estimate...

  18. Recent and relict topography of Boo Bee patch reef, Belize

    Science.gov (United States)

    Halley, R.B.; Shinn, E.A.; Hudson, J.H.; Lidz, B.; Taylor, D.L.

    1977-01-01

    Five core borings were taken on and around Boo Bee Patch Reef to better understand the origin of such shelf lagoon reefs. The cores reveal 4 stages of development: (1) subaerial exposure of a Pleistocene "high" having about 8 meters of relief, possibly a Pleistocene patch reef; (2) deposition of peat and impermeable terrigenous clay 3 meters thick around the high; (3) initiation of carbonate sediment production by corals and algae on the remaining 5 meters of hard Pleistocene topography and carbonate mud on the surrounding terrigenous clay; and (4) accelerated organic accumulation on the patch reef. Estimates of patch reef sedimentation rates (1.6 m/1000 years) are 3 to 4 times greater than off-reef sedimentation rates (0.4-0.5 m/1000 years). During periods of Pleistocene sedimentation on the Belize shelf, lagoon patch reefs may have grown above one another, stacking up to form reef accumulation of considerable thickness.

  19. Zonation of uplifted pleistocene coral reefs on barbados, west indies.

    Science.gov (United States)

    Mesolella, K J

    1967-05-05

    The coral species composition of uplifted Pleistocene reefs on Barbados is very similar to Recent West Indian reefs. Acropora palmata, Acropora cervicornis, and Montastrea annularis are qtuantitatively the most important of the coral species.

  20. 2013 SEAMAP Reef Fish Survey (PC1302, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2013 SEAMAP Reef Fish Survey were to collect video data of reef fish on western Gulf of Mexico shelf-edge banks to facilitate assessments of...

  1. Seagrass from Unified Florida Reef Tract Map (NODC Accession 0123059)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a subset of the Unified Map representing Seagrass areas. Version 1.1 - December 2013. The Unified Florida Reef Tract Map (Unified Reef Map) provides...

  2. 2015 Carbbean Reef Fish Survey (PC1505, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2015 Caribbean Reef Fish Survey were to assess relative abundance of reef fish species around the US Caribbean Islands, estimate length-frequency...

  3. 2016 SEAMAP Reef Fish Survey (PC1601, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2016 SEAMAP Reef Fish Survey were to assess relative abundance of reef fish species on continental shelf-edge banks of the Gulf of Mexico, estimate...

  4. 2013 SEAMAP Reef Fish Survey (PC1302, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2013 SEAMAP Reef Fish Survey were to collect video data of reef fish on western Gulf of Mexico shelf-edge banks to facilitate assessments of...

  5. Can we measure beauty? Computational evaluation of coral reef aesthetics

    NARCIS (Netherlands)

    Haas, A.F.; Guibert, M.; Foerschner, A.; Co, T.; Calhoun, S.; George, E.; Hatay, M.; Dinsdale, E.; Sandin, S.A.; Smith, J.E.; Vermeij, M.J.A.; Felts, B.; Dustan, P.; Salamon, P.; Rohwer, F.

    2015-01-01

    The natural beauty of coral reefs attracts millions of tourists worldwide resulting in substantial revenues for the adjoining economies. Although their visual appearance is a pivotal factor attracting humans to coral reefs current monitoring protocols exclusively target biogeochemical parameters,

  6. Assessing cryptic reef diversity of colonizing marine invertebrates using Autonomous Reef Monitoring Structures (ARMS) deployed at coral reef sites in Batangas, Philippines from 2012-03-12 to 2015-05-31 (NCEI Accession 0162829)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Autonomous Reef Monitoring Structures (ARMS) are used by the NOAA Coral Reef Ecosystem Program (CREP) to assess and monitor cryptic reef diversity across the...

  7. The Impact of Marine Protected Areas on Reef-Wide Population Structure and Fishing-Induced Phenotypes in Coral-Reef Fishes

    Science.gov (United States)

    Fidler, Robert Young, III

    using size-specific fish counts, allowing for spatiotemporal comparisons of abundance and demographic structure of fish populations across protected and fished areas. Results of the meta-analysis revealed that: (1) although fish density was higher inside MPAs than in fished reefs at each sampling period, reef-wide density often increased or remained stable over time; and (2) increases in large-bodied fish were evident reef-wide between survey periods, indicating that positive demographic shifts occurred simultaneously in both MPAs and adjacent areas. Increases in large-bodied fish were observed across a range of taxa, but were most prominent in families directly targeted by fishermen. These results suggest that over relatively few years of protection, Philippine MPAs promoted beneficial shifts in population structure throughout entire reef systems, rather than simply maintaining stable populations within their borders. Relationships between MPA age and shifts in fish density or demographic structure were rare, but may have been precluded by the relatively short period between replicate surveys. Although increases in fish density inside MPAs were occasionally associated with MPA size, there were no significant relationships between the size of MPAs and reef-wide increases in fish density. The reef-wide framework of MPA assessment used in this study has the advantage of treating MPAs and fished reefs as an integrated system, thus revealing trends that would be indistinguishable in traditional spatial comparisons between MPAs and fished reefs. The impact of MPAs on fishing-induced life-history traits was assessed by comparing growth and maturation patterns exhibited by six reef-fish species inside and outside five MPAs and adjacent, fished reefs in Zambales, Luzon, Philippines. This analysis demonstrated considerable variation in terminal body-sizes (Linf) and growth rates (K) between conspecifics in MPAs and fished reefs. Three of the four experimental species directly

  8. Parameters Controlling Sediment Composition of Modern and Pleistocene Jamaican Reefs

    OpenAIRE

    Boss, Stephen K.

    1985-01-01

    Recent carbonate sediments from Jamaican north coast fringing reefs display variation in constituent composition, texture, and mineralogy related to their location on the reef. Samples were collected along lines which traversed the back reef and fore reef (0.5m to 70m). The sediment is dominated by highly comminuted coral fragments, plates of the calcareous green alga, Halimeda, coralline algae, and the encrusting Foraminifera, Homotrema rubrum, with lesser amounts of other taxonomic group...

  9. Wave Dissipation on Low- to Super-Energy Coral Reefs

    Science.gov (United States)

    Harris, D. L.

    2016-02-01

    Coral reefs are valuable, complex and bio-diverse ecosystems and are also known to be one of the most effective barriers to swell events in coastal environments. Previous research has found coral reefs to be remarkably efficient in removing most of the wave energy during the initial breaking and transformation on the reef flats. The rate of dissipation is so rapid that coral reefs have been referred to as rougher than any known coastal barrier. The dissipation of wave energy across reef flats is crucial in maintaining the relatively low-energy conditions in the back reef and lagoonal environments providing vital protection to adjacent beach or coastal regions from cyclone and storm events. A shift in the regulation of wave energy by reef flats could have catastrophic consequences ecologically, socially, and economically. This study examined the dissipation of wave energy during two swell events in Tahiti and Moorea, French Polyesia. Field sites were chosen in varying degrees of exposure and geomorphology from low-energy protected sites (Tiahura, Moorea) to super-energy sites (Teahupo'o, Tahiti). Waves were measured during two moderate to large swell events in cross reef transects using short-term high-resolution pressure transducers. Wave conditions were found to be similar in all back reef locations despite the very different wave exposure at each reef site. However, wave conditions on the reef flats were different and mirrored the variation in wave exposure with depth over the reef flat the primary regulator of reef flat wave height. These results indicate that coral reef flats evolve morphodynamically with the wave climate, which creates coral reef geomorphologies capable of dissipating wave energy that results in similar back reef wave conditions regardless of the offshore wave climate.

  10. The Future of Coral Reefs Subject to Rapid Climate Change: Lessons from Natural Extreme Environments

    Directory of Open Access Journals (Sweden)

    Emma F. Camp

    2018-02-01

    Full Text Available Global climate change and localized anthropogenic stressors are driving rapid declines in coral reef health. In vitro experiments have been fundamental in providing insight into how reef organisms will potentially respond to future climates. However, such experiments are inevitably limited in their ability to reproduce the complex interactions that govern reef systems. Studies examining coral communities that already persist under naturally-occurring extreme and marginal physicochemical conditions have therefore become increasingly popular to advance ecosystem scale predictions of future reef form and function, although no single site provides a perfect analog to future reefs. Here we review the current state of knowledge that exists on the distribution of corals in marginal and extreme environments, and geographic sites at the latitudinal extremes of reef growth, as well as a variety of shallow reef systems and reef-neighboring environments (including upwelling and CO2 vent sites. We also conduct a synthesis of the abiotic data that have been collected at these systems, to provide the first collective assessment on the range of extreme conditions under which corals currently persist. We use the review and data synthesis to increase our understanding of the biological and ecological mechanisms that facilitate survival and success under sub-optimal physicochemical conditions. This comprehensive assessment can begin to: (i highlight the extent of extreme abiotic scenarios under which corals can persist, (ii explore whether there are commonalities in coral taxa able to persist in such extremes, (iii provide evidence for key mechanisms required to support survival and/or persistence under sub-optimal environmental conditions, and (iv evaluate the potential of current sub-optimal coral environments to act as potential refugia under changing environmental conditions. Such a collective approach is critical to better understand the future survival of

  11. Individual-based analyses reveal limited functional overlap in a coral reef fish community.

    Science.gov (United States)

    Brandl, Simon J; Bellwood, David R

    2014-05-01

    Detailed knowledge of a species' functional niche is crucial for the study of ecological communities and processes. The extent of niche overlap, functional redundancy and functional complementarity is of particular importance if we are to understand ecosystem processes and their vulnerability to disturbances. Coral reefs are among the most threatened marine systems, and anthropogenic activity is changing the functional composition of reefs. The loss of herbivorous fishes is particularly concerning as the removal of algae is crucial for the growth and survival of corals. Yet, the foraging patterns of the various herbivorous fish species are poorly understood. Using a multidimensional framework, we present novel individual-based analyses of species' realized functional niches, which we apply to a herbivorous coral reef fish community. In calculating niche volumes for 21 species, based on their microhabitat utilization patterns during foraging, and computing functional overlaps, we provide a measurement of functional redundancy or complementarity. Complementarity is the inverse of redundancy and is defined as less than 50% overlap in niche volumes. The analyses reveal extensive complementarity with an average functional overlap of just 15.2%. Furthermore, the analyses divide herbivorous reef fishes into two broad groups. The first group (predominantly surgeonfishes and parrotfishes) comprises species feeding on exposed surfaces and predominantly open reef matrix or sandy substrata, resulting in small niche volumes and extensive complementarity. In contrast, the second group consists of species (predominantly rabbitfishes) that feed over a wider range of microhabitats, penetrating the reef matrix to exploit concealed surfaces of various substratum types. These species show high variation among individuals, leading to large niche volumes, more overlap and less complementarity. These results may have crucial consequences for our understanding of herbivorous processes on

  12. Coral Reefs: A Gallery Program, Grades 7-12.

    Science.gov (United States)

    National Aquarium in Baltimore, MD. Dept. of Education.

    Gallery classes at the National Aquarium in Baltimore give the opportunity to study specific aquarium exhibits which demonstrate entire natural habitats. The coral reef gallery class features the gigantic western Atlantic coral reef (325,000 gallons) with over 1,000 fish. The exhibit simulates a typical Caribbean coral reef and nearby sandy…

  13. Developing a multi-stressor gradient for coral reefs

    Science.gov (United States)

    Coral reefs are often found near coastal waters where multiple anthropogenic stressors co-occur at areas of human disturbance. Developing coral reef biocriteria under the U.S. Clean Water Act requires relationships between anthropogenic stressors and coral reef condition to be es...

  14. 78 FR 67128 - Coral Reef Conservation Program; Meeting

    Science.gov (United States)

    2013-11-08

    ... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Coral Reef Conservation Program; Meeting AGENCY: Coral Reef Conservation Program, Office of Ocean and Coastal Resource Management... meeting of the U.S. Coral Reef Task Force (USCRTF). The meeting will be held in Christiansted, U.S. Virgin...

  15. Coral identity underpins architectural complexity on Caribbean reefs.

    Science.gov (United States)

    Alvarez-Filip, Lorenzo; Dulvy, Nicholas K; Côte, Isabelle M; Watkinson, Andrew R; Gill, Jennifer A

    2011-09-01

    The architectural complexity of ecosystems can greatly influence their capacity to support biodiversity and deliver ecosystem services. Understanding the components underlying this complexity can aid the development of effective strategies for ecosystem conservation. Caribbean coral reefs support and protect millions of livelihoods, but recent anthropogenic change is shifting communities toward reefs dominated by stress-resistant coral species, which are often less architecturally complex. With the regionwide decline in reef fish abundance, it is becoming increasingly important to understand changes in coral reef community structure and function. We quantify the influence of coral composition, diversity, and morpho-functional traits on the architectural complexity of reefs across 91 sites at Cozumel, Mexico. Although reef architectural complexity increases with coral cover and species richness, it is highest on sites that are low in taxonomic evenness and dominated by morpho-functionally important, reef-building coral genera, particularly Montastraea. Sites with similar coral community composition also tend to occur on reefs with very similar architectural complexity, suggesting that reef structure tends to be determined by the same key species across sites. Our findings provide support for prioritizing and protecting particular reef types, especially those dominated by key reef-building corals, in order to enhance reef complexity.

  16. Nursery function of tropical back-reef systems

    NARCIS (Netherlands)

    Adams, A.J.; Dahlgren, C.P.; Kellison, G.T.; Kendall, M.S.; Layman, C.A.; Ley, J.A.; Nagelkerken, I.; Serafy, J.E.

    2006-01-01

    Similar to nearshore systems in temperate latitudes, the nursery paradigm for tropical back-reef systems is that they provide a habitat for juveniles of species that subsequently make ontogenetic shifts to adult populations on coral reefs (we refer to this as the nursery function of back-reef

  17. New directions in coral reef microbial ecology.

    Science.gov (United States)

    Garren, Melissa; Azam, Farooq

    2012-04-01

    Microbial processes largely control the health and resilience of coral reef ecosystems, and new technologies have led to an exciting wave of discovery regarding the mechanisms by which microbial communities support the functioning of these incredibly diverse and valuable systems. There are three questions at the forefront of discovery: What mechanisms underlie coral reef health and resilience? How do environmental and anthropogenic pressures affect ecosystem function? What is the ecology of microbial diseases of corals? The goal is to understand the functioning of coral reefs as integrated systems from microbes and molecules to regional and ocean-basin scale ecosystems to enable accurate predictions of resilience and responses to perturbations such as climate change and eutrophication. This review outlines recent discoveries regarding the microbial ecology of different microenvironments within coral ecosystems, and highlights research directions that take advantage of new technologies to build a quantitative and mechanistic understanding of how coral health is connected through microbial processes to its surrounding environment. The time is ripe for natural resource managers and microbial ecologists to work together to create an integrated understanding of coral reef functioning. In the context of long-term survival and conservation of reefs, the need for this work is immediate. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  18. Ecological Processes and Contemporary Coral Reef Management

    Directory of Open Access Journals (Sweden)

    Angela Dikou

    2010-05-01

    Full Text Available Top-down controls of complex foodwebs maintain the balance among the critical groups of corals, algae, and herbivores, thus allowing the persistence of corals reefs as three-dimensional, biogenic structures with high biodiversity, heterogeneity, resistance, resilience and connectivity, and the delivery of essential goods and services to societies. On contemporary reefs world-wide, however, top-down controls have been weakened due to reduction in herbivory levels (overfishing or disease outbreak while bottom-up controls have increased due to water quality degradation (increase in sediment and nutrient load and climate forcing (seawater warming and acidification leading to algal-dominated alternate benthic states of coral reefs, which are indicative of a trajectory towards ecological extinction. Management to reverse common trajectories of degradation for coral reefs necessitates a shift from optimization in marine resource use and conservation towards building socio-economic resilience into coral reef systems while attending to the most manageable human impacts (fishing and water quality and the global-scale causes (climate change.

  19. Quaternary Magmatism in the Cascades - Geologic Perspectives

    Science.gov (United States)

    Hildreth, Wes

    2007-01-01

    Foreward The Cascade magmatic arc is a belt of Quaternary volcanoes that extends 1,250 km from Lassen Peak in northern California to Meager Mountain in Canada, above the subduction zone where the Juan de Fuca Plate plunges beneath the North American Plate. This Professional Paper presents a synthesis of the entire volcanic arc, addressing all 2,300 known Quaternary volcanoes, not just the 30 or so visually prominent peaks that comprise the volcanic skyline. Study of Cascade volcanoes goes back to the geological explorers of the late 19th century and the seminal investigations of Howel Williams in the 1920s and 1930s. However, major progress and application of modern scientific methods and instrumentation began only in the 1970s with the advent of systematic geological, geophysical, and geochemical studies of the entire arc. Initial stimulus from the USGS Geothermal Research Program was enhanced by the USGS Volcano Hazards Program following the 1980 eruption of Mount St. Helens. Together, these two USGS Programs have provided more than three decades of stable funding, staffing, and analytical support. This Professional Paper summarizes the resultant USGS data sets and integrates them with the parallel contributions of other investigators. The product is based upon an all-encompassing and definitive geological database, including chemical and isotopic analyses to characterize the rocks and geochronology to provide the critical time constraints. Until now, this massive amount of data has not been summarized, and a systematic and uniform interpretation firmly grounded in geological fact has been lacking. Herein lies the primary utility of this Cascade volume. It not only will be the mandatory starting point for new workers, but also will provide essential geological context to broaden the perspectives of current investigators of specific Cascade volcanoes. Wes Hildreth's insightful understanding of volcanic processes and his uncompromising scientific integrity make him

  20. Variability in the phytoplankton community of Kavaratti reef ecosystem (northern Indian Ocean) during peak and waning periods of El Niño 2016.

    Science.gov (United States)

    Karati, Kusum Komal; Vineetha, G; Madhu, N V; Anil, P; Dayana, M; Shihab, B K; Muhsin, A I; Riyas, C; Raveendran, T V

    2017-11-29

    El Niño, an interannual climate event characterized by elevated oceanic temperature, is a prime threat for coral reef ecosystems worldwide, owing to their thermal threshold sensitivity. Phytoplankton plays a crucial role in the sustenance of reef trophodynamics. The cell size of the phytoplankton forms the "master morphological trait" with implications for growth, resource acquisition, and adaptability to nutrients. In the context of a strong El Niño prediction for 2015-2016, the present study was undertaken to evaluate the variations in the size-structured phytoplankton of Kavaratti reef waters, a major coral atoll along the southeast coast of India. The present study witnessed a remarkable change in the physicochemical environment of the reef water and massive coral bleaching with the progression of El Niño 2015-2016 from its peak to waning phase. The fluctuations observed in sea surface temperature, pH, and nutrient concentration of the reef water with the El Niño progression resulted in a remarkable shift in phytoplankton size structure, abundance, and community composition of the reef waters. Though low nutrient concentration of the waning phase resulted in lower phytoplankton biomass and abundance, the diazotroph Trichodesmium erythraeum predominated the reef waters, owing to its capability of the atmospheric nitrogen fixation and dissolved organic phosphate utilization.

  1. Coral reef soundscapes may not be detectable far from the reef

    Science.gov (United States)

    Kaplan, Maxwell B.; Mooney, T. Aran

    2016-08-01

    Biological sounds produced on coral reefs may provide settlement cues to marine larvae. Sound fields are composed of pressure and particle motion, which is the back and forth movement of acoustic particles. Particle motion (i.e., not pressure) is the relevant acoustic stimulus for many, if not most, marine animals. However, there have been no field measurements of reef particle motion. To address this deficiency, both pressure and particle motion were recorded at a range of distances from one Hawaiian coral reef at dawn and mid-morning on three separate days. Sound pressure attenuated with distance from the reef at dawn. Similar trends were apparent for particle velocity but with considerable variability. In general, average sound levels were low and perhaps too faint to be used as an orientation cue except very close to the reef. However, individual transient sounds that exceeded the mean values, sometimes by up to an order of magnitude, might be detectable far from the reef, depending on the hearing abilities of the larva. If sound is not being used as a long-range cue, it might still be useful for habitat selection or other biological activities within a reef.

  2. Pseudoimpactites in anthropocenically overprinted quaternary sediments

    Science.gov (United States)

    Huber, Robert; Darga, Robert; Lauterbach, Hans

    2017-04-01

    Whereas typical anthropogenic materials such as plastics can easily be identified in the anthropocene record, other materials such as building materials or industrial waste often closely resemble natural rocks or minerals. Especially transported and weathered anthropocenic matter is hard to distinguish from natural rocks. Whereas most rock samples may easily be distinguished by visual inspection, definite identification of exotic and small sized matter is not always an easy exercise which has been shown during the controversial discussion on the cosmic origin of carbon spherules found in Younger Dryas sediments. Similarly, a variety of exotic materials and lithological phenomena reported from quaternary sediments in Upper Bavaria have been associated to a cosmic impact in the area. Findings of carbonatic regmaglypts, glass coated and fragmented rocks, glassy carbon or pumice like carbon have been proposed to represent impact related rocks, an hypothesis which has further been supported by findings of iron silicides and the postulated detection of nanodiamonds and Carbine. Many of these findings have been strongly doubted within the geoscientific community, however a systematic, independent investigation of these phenomena has not yet been conducted. We present the results of our examinations which have been carried out to critically test the impact related origin of the mentioned strange materials and rocks. We could identify some key sites and independently collected samples of several of the materials and analysed these thoroughly. We found that the majority of these impact related materials is of anthropogenic or biogenic origin, thus they are pseudoimpactites partly originating from old fireplaces and waste pits. The claimed cosmic origin of this matter is an illusion caused by the anthropocene overprint of the original sedimentary record.

  3. ZnO nanocoral reef grown on porous silicon substrates without catalyst

    International Nuclear Information System (INIS)

    Abdulgafour, H.I.; Yam, F.K.; Hassan, Z.; AL-Heuseen, K.; Jawad, M.J.

    2011-01-01

    Research highlights: → Porous silicon (PS) technology is utilized to grow coral reef-like ZnO nanostructures on the surface of Si substrates. → Flower-like aligned ZnO nanorods are fabricated directly onto the silicon substrates through zinc powder evaporation using a simple thermal evaporation method without a catalyst for comparison. → The PL spectra show that for ZnO nanocoral reefs the UV emission shifts slightly towards lower frequency. → This non-catalyst growth technique on the rough surface of substrates may have potential applications in the fabrication of nanoelectronic and nanooptical devices. - Abstract: Porous silicon (PS) technology is utilized to grow coral reef-like ZnO nanostructures on the surface of Si substrates with rough morphology. Flower-like aligned ZnO nanorods are also fabricated directly onto the silicon substrates through zinc powder evaporation using a simple thermal evaporation method without a catalyst for comparison. The characteristics of these nanostructures are investigated using field-emission scanning electron microscopy, grazing-angle X-ray diffraction (XRD), and photoluminescence (PL) measurements of structures grown on both Si and porous Si substrates. The texture coefficient obtained from the XRD spectra indicates that the coral reef-like nanostructures are highly oriented on the porous silicon substrate with decreasing nanorods length and diameter from 800-900 nm to 3.5-5.5 μm and from 217-229 nm to 0.6-0.7 μm, respectively. The PL spectra show that for ZnO nanocoral reefs the UV emission shifts slightly towards lower frequency and the intensity increase with the improvement of ZnO crystallization. This non-catalyst growth technique on the rough surface of substrates may have potential applications in the fabrication of nanoelectronic and nanooptical devices.

  4. ZnO nanocoral reef grown on porous silicon substrates without catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Abdulgafour, H.I., E-mail: hind_alshaikh@yahoo.com [School of Physics, University Sains Malaysia 11800 Penang (Malaysia); Yam, F.K.; Hassan, Z.; AL-Heuseen, K.; Jawad, M.J. [School of Physics, University Sains Malaysia 11800 Penang (Malaysia)

    2011-05-05

    Research highlights: > Porous silicon (PS) technology is utilized to grow coral reef-like ZnO nanostructures on the surface of Si substrates. > Flower-like aligned ZnO nanorods are fabricated directly onto the silicon substrates through zinc powder evaporation using a simple thermal evaporation method without a catalyst for comparison. > The PL spectra show that for ZnO nanocoral reefs the UV emission shifts slightly towards lower frequency. > This non-catalyst growth technique on the rough surface of substrates may have potential applications in the fabrication of nanoelectronic and nanooptical devices. - Abstract: Porous silicon (PS) technology is utilized to grow coral reef-like ZnO nanostructures on the surface of Si substrates with rough morphology. Flower-like aligned ZnO nanorods are also fabricated directly onto the silicon substrates through zinc powder evaporation using a simple thermal evaporation method without a catalyst for comparison. The characteristics of these nanostructures are investigated using field-emission scanning electron microscopy, grazing-angle X-ray diffraction (XRD), and photoluminescence (PL) measurements of structures grown on both Si and porous Si substrates. The texture coefficient obtained from the XRD spectra indicates that the coral reef-like nanostructures are highly oriented on the porous silicon substrate with decreasing nanorods length and diameter from 800-900 nm to 3.5-5.5 {mu}m and from 217-229 nm to 0.6-0.7 {mu}m, respectively. The PL spectra show that for ZnO nanocoral reefs the UV emission shifts slightly towards lower frequency and the intensity increase with the improvement of ZnO crystallization. This non-catalyst growth technique on the rough surface of substrates may have potential applications in the fabrication of nanoelectronic and nanooptical devices.

  5. Does elevated pCO2 affect reef octocorals?

    Science.gov (United States)

    Gabay, Yasmin; Benayahu, Yehuda; Fine, Maoz

    2013-03-01

    Increasing anthropogenic pCO2 alters seawater chemistry, with potentially severe consequences for coral reef growth and health. Octocorals are the second most important faunistic component in many reefs, often occupying 50% or more of the available substrate. Three species of octocorals from two families were studied in Eilat (Gulf of Aqaba), comprising the zooxanthellate Ovabunda macrospiculata and Heteroxenia fuscescens (family Xeniidae), and Sarcophyton sp. (family Alcyoniidae). They were maintained under normal (8.2) and reduced (7.6 and 7.3) pH conditions for up to 5 months. Their biolological features, including protein concentration, polyp weight, density of zooxanthellae, and their chlorophyll concentration per cell, as well as polyp pulsation rate, were examined under conditions more acidic than normal, in order to test the hypothesis that rising pCO2 would affect octocorals. The results indicate no statistically significant difference between the octocorals exposed to reduced pH values compared to the control. It is therefore suggested that the octocorals' tissue may act as a protective barrier against adverse pH conditions, thus maintaining them unharmed at high levels of pCO2.

  6. Artificial Reefs in Motion: Legacy of changes and degradation at the Redbird Reef Site

    Science.gov (United States)

    Trembanis, A. C.; DuVal, C.; Peter, B.

    2016-12-01

    Artificial reefs are used for a variety of purposes at sites throughout the U.S. and around the globe, yet little, if any, long-term monitoring has been conducted with the goal of understanding inter-annual changes to the emplaced structures. Throughout the U.S. Mid-Atlantic region, several programs utilized retired subway cars as disposal structures to form artificial reefs. One such site, known as site 11, or "Redbird Reef", is located off the coast of Delaware and was at one time home to 997 former NYC subway cars. Opportunistic sonar surveys at the site have been conducted between 2008 and 2016 providing one of the most extensive and repeated mapping studies for this type of reef. Previous studies conducted by our group at the site have focused on understanding wave orbital ripple dynamics and scour patterns. In this present study, we analyze the changes apparent at the site itself, focused on the storm-response dynamics of the subway cars. Results have shown that Superstorm Sandy in 2012 produced dramatic changes to the reef structures resulting in the total or partial destruction of eight subway cars within a small (.45 x .2km) portion of the reef site. Winter Storm Jonas in 2016 resulted in the destruction of fewer cars, but rotated a previously static 47m long Navy barge nearly 60 degrees. Once destroyed or collapsed by waves the subway cars go from providing positive structural relief and thus beneficial habitat above the surrounding seabed to being reduced to scattered low relief marine debris. A once popular consideration for reef material, the event and inter-annual decay of subway cars as observed at the Redbird reef provides both a stark indication of the power of storm dynamics on the inner-shelf and a cautionary tale with regards to the selection of seabed reef material.

  7. Theoretical study of quaternary compounds as thin-film solar cell absorber

    International Nuclear Information System (INIS)

    Su, Huai Wei

    2010-01-01

    Full text : Design of chalcogenide photovoltaic absorbers is carried out systematically through sequential cation mutation, from binary to ternary to quaternary compounds, using first-principles electronic structure calculations. Several universal trends are found for the ternary and two classes of quaternary chalcogenides. For example, the lowest-energy structure always has larger lattice constant a, smaller tetragonal distortion parameter η=c/2a, and larger band gap than the metastable structures for common-row cation mutations. The band gap is reduced during the mutation. The band gap decreases from binary II-VI to ternary I-III-VI 2 are mostly due to the p-d repulsion in the valence band, the decreases from ternary I-III-VI 2 to quaternary I 2 -II-IV-VI 4 chalcogenides are due to the downshift in the conduction band caused by the wavefunction localization on the group IV cation site. It was found that I 2 -II-IV-VI 4 compounds are more stable in the kesterite structure, whereas the widely-assumed stannite structure reported in the literature is most likely due to partial disorder in the I-II layer of the kesterite phase. Among the derived quaternary compounds, Cu 2 ZnSnS 4 (CZTS) is one of the ideal candidate absorber materials for thin-film solar cells with an optimal band gap, high absorption coefficient, abundant elemental components, and is adaptable to various growth techniques. It was performed a series of first-principles electronic structure calculations for CZTS. Also it was found that in the ground state kesterite structure, (i) the chemical potential region that CZTS can form is very small. Therefore, it will be very difficult to obtain high quality stoichiometric CZTS samples; (ii) The dominant p-type acceptor in CZTS is CuZn, however, the associated acceptor level is relatively high, suggesting that p-type doping in CZTS is more difficult than ternary compounds such as CuInSe 2 ; (iii) The formation of the self-compensated defect pair [Cu

  8. Preparation and Characterization of Novel Cationic Chitosan Derivatives Bearing Quaternary Ammonium and Phosphonium Salts and Assessment of Their Antifungal Properties.

    Science.gov (United States)

    Tan, Wenqiang; Li, Qing; Dong, Fang; Chen, Qiuhong; Guo, Zhanyong

    2017-08-31

    Chitosan is an abundant and renewable polysaccharide, its derivatives exhibit attractive bioactivities and the wide applications in various biomedical fields. In this paper, two novel cationic chitosan derivatives modified with quaternary phosphonium salts were successfully synthesized via trimethylation, chloride acetylation, and quaternization with tricyclohexylphosphine and triphenylphosphine. The structures and properties of synthesized products in the reactions were characterized by FTIR spectroscopy, ¹H-NMR, 31 P-NMR, elemental and thermogravimetric analysis. The antifungal activities of chitosan derivatives against four kinds of phytopathogens, including Phomopsis asparagi , Watermelon fusarium , Colletotrichum lagenarium , and Fusarium oxysporum were tested using the radial growth assay in vitro. The results revealed that the synthesized cationic chitosan derivatives showed significantly improved antifungal efficiency compared to chitosan. It was reasonably suggested that quaternary phosphonium groups enabled the obviously stronger antifungal activity of the synthesized chitosans. Especially, the triphenylphosphonium-functionalized chitosan derivative inhibited the growth of Phomopsis asparagi most effectively, with inhibitory indices of about 80% at 0.5 mg/mL. Moreover, the data demonstrated that the substituted groups with stronger electron-withdrawing ability relatively possessed greater antifungal activity. The results suggest the possibility that cationic chitosan derivatives bearing quaternary phosphonium salts could be effectively employed as novel antifungal biomaterials for application in the field of agriculture.

  9. Climate change, global warming and coral reefs: modelling the effects of temperature.

    Science.gov (United States)

    Crabbe, M James C

    2008-10-01

    Climate change and global warming have severe consequences for the survival of scleractinian (reef-building) corals and their associated ecosystems. This review summarizes recent literature on the influence of temperature on coral growth, coral bleaching, and modelling the effects of high temperature on corals. Satellite-based sea surface temperature (SST) and coral bleaching information available on the internet is an important tool in monitoring and modelling coral responses to temperature. Within the narrow temperature range for coral growth, corals can respond to rate of temperature change as well as to temperature per se. We need to continue to develop models of how non-steady-state processes such as global warming and climate change will affect coral reefs.

  10. New protection initiatives announced for coral reefs

    Science.gov (United States)

    Showstack, Randy

    Off the coasts of some of the South Pacific's most idyllic-sounding atolls, Austin Bowden-Kerby has seen first-hand the heavy damage to coral reefs from dynamite and cyanide fishing. For instance, while snorkeling near Chuuk, an island in Micronesia, he has observed craters and rubble beds of coral, which locals have told him date to World War II ordnance.A marine biologist and project scientist for the Coral Gardens Initiative of the Foundation for the Peoples of the South Pacific, Bowden-Kerby has also identified what he says are some public health effects related to destroyed coral reefs and their dying fisheries. These problems include protein and vitamin A deficiency and blindness, all of which may—in some instances—be linked to poor nutrition resulting from lower reef fish consumption by islanders, according to Bowden-Kerby.

  11. Restoration of oyster reefs in an estuarine lake: population dynamics and shell accretion

    Science.gov (United States)

    Casas, Sandra M.; La Peyre, Jerome F.; La Peyre, Megan K.

    2015-01-01

    Restoration activities inherently depend on understanding the spatial and temporal variation in basic demographic rates of the species of interest. For species that modify and maintain their own habitat such as the eastern oyster Crassostrea virginica, understanding demographic rates and their impacts on population and habitat success are crucial to ensuring restoration success. We measured oyster recruitment, density, size distribution, biomass, mortality and Perkinsus marinus infection intensity quarterly for 3 yr on shallow intertidal reefs created with shell cultch in March 2009. All reefs were located within Sister Lake, LA. Reefs were placed in pairs at 3 different locations within the lake; pairs were placed in low and medium energy sites within each location. Restored reefs placed within close proximity (biomass (>14.6 kg m-2) at the end of 3 yr. Shell accretion, on average, exceeded estimated rates required to keep pace with local subsidence and shell loss. Variation in recruitment, growth and survival drives local site-specific population success, which highlights the need to understand local water quality, hydrodynamics, and metapopulation dynamics when planning restoration.

  12. Effects of Protection and Sediment Stress on Coral Reefs in Saint Lucia.

    Science.gov (United States)

    Bégin, Chantale; Schelten, Christiane K; Nugues, Maggy M; Hawkins, Julie; Roberts, Callum; Côté, Isabelle M

    2016-01-01

    The extent to which Marine Protected Areas (MPAs) benefit corals is contentious. On one hand, MPAs could enhance coral growth and survival through increases in herbivory within their borders; on the other, they are unlikely to prevent disturbances, such as terrestrial runoff, that originate outside their boundaries. We examined the effect of spatial protection and terrestrial sediment on the benthic composition of coral reefs in Saint Lucia. In 2011 (10 to 16 years after MPAs were created), we resurveyed 21 reefs that had been surveyed in 2001 and analyzed current benthic assemblages as well as changes in benthic cover over that decade in relation to protection status, terrestrial sediment influence (measured as the proportion of terrigenous material in reef-associated sediment) and depth. The cover of all benthic biotic components has changed significantly over the decade, including a decline in coral and increase in macroalgae. Protection status was not a significant predictor of either current benthic composition or changes in composition, but current cover and change in cover of several components were related to terrigenous content of sediment deposited recently. Sites with a higher proportion of terrigenous sediment had lower current coral cover, higher macroalgal cover and greater coral declines. Our results suggest that terrestrial sediment is an important factor in the recent degradation of coral reefs in Saint Lucia and that the current MPA network should be complemented by measures to reduce runoff from land.

  13. Effects of Protection and Sediment Stress on Coral Reefs in Saint Lucia.

    Directory of Open Access Journals (Sweden)

    Chantale Bégin

    Full Text Available The extent to which Marine Protected Areas (MPAs benefit corals is contentious. On one hand, MPAs could enhance coral growth and survival through increases in herbivory within their borders; on the other, they are unlikely to prevent disturbances, such as terrestrial runoff, that originate outside their boundaries. We examined the effect of spatial protection and terrestrial sediment on the benthic composition of coral reefs in Saint Lucia. In 2011 (10 to 16 years after MPAs were created, we resurveyed 21 reefs that had been surveyed in 2001 and analyzed current benthic assemblages as well as changes in benthic cover over that decade in relation to protection status, terrestrial sediment influence (measured as the proportion of terrigenous material in reef-associated sediment and depth. The cover of all benthic biotic components has changed significantly over the decade, including a decline in coral and increase in macroalgae. Protection status was not a significant predictor of either current benthic composition or changes in composition, but current cover and change in cover of several components were related to terrigenous content of sediment deposited recently. Sites with a higher proportion of terrigenous sediment had lower current coral cover, higher macroalgal cover and greater coral declines. Our results suggest that terrestrial sediment is an important factor in the recent degradation of coral reefs in Saint Lucia and that the current MPA network should be complemented by measures to reduce runoff from land.

  14. Phylogenetic perspectives on reef fish functional traits.

    Science.gov (United States)

    Floeter, Sergio R; Bender, Mariana G; Siqueira, Alexandre C; Cowman, Peter F

    2018-02-01

    Functional traits have been fundamental to the evolution and diversification of entire fish lineages on coral reefs. Yet their relationship with the processes promoting speciation, extinction and the filtering of local species pools remains unclear. We review the current literature exploring the evolution of diet, body size, water column use and geographic range size in reef-associated fishes. Using published and new data, we mapped functional traits on to published phylogenetic trees to uncover evolutionary patterns that have led to the current functional diversity of fishes on coral reefs. When examining reconstructed patterns for diet and feeding mode, we found examples of independent transitions to planktivory across different reef fish families. Such transitions and associated morphological alterations may represent cases in which ecological opportunity for the exploitation of different resources drives speciation and adaptation. In terms of body size, reconstructions showed that both large and small sizes appear multiple times within clades of mid-sized fishes and that extreme body sizes have arisen mostly in the last 10 million years (Myr). The reconstruction of range size revealed many cases of disparate range sizes among sister species. Such range size disparity highlights potential vicariant processes through isolation in peripheral locations. When accounting for peripheral speciation processes in sister pairs, we found a significant relationship between labrid range size and lineage age. The diversity and evolution of traits within lineages is influenced by trait-environment interactions as well as by species and trait-trait interactions, where the presence of a given trait may trigger the development of related traits or behaviours. Our effort to assess the evolution of functional diversity across reef fish clades adds to the burgeoning research focusing on the evolutionary and ecological roles of functional traits. We argue that the combination of a

  15. Warm-water coral reefs and climate change.

    Science.gov (United States)

    Spalding, Mark D; Brown, Barbara E

    2015-11-13

    Coral reefs are highly dynamic ecosystems that are regularly exposed to natural perturbations. Human activities have increased the range, intensity, and frequency of disturbance to reefs. Threats such as overfishing and pollution are being compounded by climate change, notably warming and ocean acidification. Elevated temperatures are driving increasingly frequent bleaching events that can lead to the loss of both coral cover and reef structural complexity. There remains considerable variability in the distribution of threats and in the ability of reefs to survive or recover from such disturbances. Without significant emissions reductions, however, the future of coral reefs is increasingly bleak. Copyright © 2015, American Association for the Advancement of Science.

  16. Identification of Coral Reefs in Mamburit Waters, Sumenep Regency

    OpenAIRE

    Sawiya, Sawiya; Mahmudi, Mohammad; Guntur, Guntur

    2014-01-01

    This research was conducted in September to October 2013 in Mamburit Waters, Sumenep Regency. This study was aimed to assess the percentage of coral reefs and acknowkedge the type of the coral reefs. Coral reefs was observed with the Line Intercept (LIT) method laid parallel to the coastline in the depth of 3 m and 10 m in windward and leeward area. Total of 59.88% coral reefs lived in leeward area in 3 m depth includes in good category and the percentage of dead coral reefs and other fauna f...

  17. Biological impacts of oil pollution: coral reefs

    Energy Technology Data Exchange (ETDEWEB)

    Knap, A H [Bermuda Biological Station, Ferry Reach (Bermuda)

    1992-01-01

    Coral reefs are the largest structures made by living things and exist as extremely productive ecosystems in tropical and sub-tropical areas of the world. Their location in nearshore waters means that there is a potential danger to corals from tanker accidents, refinery operations, oil exploration and production. There are now a number of published scientific papers concerning the effects of oils on corals. This report summarises and interprets the findings, and provides background information on the structure and ecology of coral reefs. Clean-up options and their implications are discussed in the light of the latest evidence from case histories and field experiments. (author)

  18. Upwellings mitigated Plio–Pleistocene heat stress for reef corals on the Florida platform (USA)

    OpenAIRE

    T. C. Brachert; M. Reuter; S. Krüger; J. Kirkerowicz; J. S. Klaus

    2015-01-01

    The fast growing calcareous skeletons of zooxanthellate reef corals (z-corals) represent unique environmental proxy archives through their oxygen and carbon stable isotope composition (δ18O, δ13C). In addition, the accretion of the skeleton itself is ultimately linked to the environment and responds with variable growth rates (extension rate) and density to environmental changes. Here we present classical proxy data (δ18O, δ13C) i...

  19. Upwellings mitigated Plio-Pleistocene heat stress for reef corals on the Florida platform (USA)

    OpenAIRE

    Brachert, Thomas C.; Reuter, Markus; Krüger, Stefan; Kirkerowicz, Julia; Klaus, James S.

    2016-01-01

    The fast growing calcareous skeletons of zooxanthellate reef corals (z corals) represent unique environmental proxy archives through their oxygen and carbon stable isotope composition (δ18O, δ13C). In addition, the accretion of the skeleton itself is ultimately linked to the environment and responds with variable growth rates (extension rate) and density to environmental changes. Here we present classical proxy data (δ18O, δ13C) in combination with calcification records from...

  20. Quaternary naltrexone reverses radiogenic and morphine-induced locomotor hyperactivity

    Energy Technology Data Exchange (ETDEWEB)

    Mickley, G.A.; Stevens, K.E.; Galbraith, J.A.; White, G.A.; Gibbs, G.L.

    1984-04-01

    The present study attempted to determine the relative role of the peripheral and central nervous system in the production of morphine-induced or radiation-induced locomotor hyperactivity of the mouse. Toward this end, we used a quaternary derivative of an opiate antagonist (naltrexone methobromide), which presumably does not cross the blood-brain barrier. Quaternary naltrexone was used to challenge the stereotypic locomotor response observed in these mice after either an i.p. injection of morphine or exposure to 1500 rads /sup 60/Co. The quaternary derivative of naltrexone reversed the locomotor hyperactivity normally observed in the C57BL/6J mouse after an injection of morphine. It also significantly attenuated radiation-induced locomotion. The data reported here support the hypothesis of endorphin involvement in radiation-induced and radiogenic behaviors. However, these conclusions are contingent upon further research which more fully evaluates naltrexone methobromide's capacity to cross the blood-brain barrier.

  1. Absolute age determination of quaternary fault and formation

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Kwang Sik; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2002-04-15

    The annual ('01-'01) objective of this project is to data the fault activity for the presumed quaternary fault zones to the western part of the Ulsam fault system and southeastern coastal area near the Wolseong Nuclear Power Plant. Rb-Sr, K-Ar, OSL, C-14 and U-series disequilibrium methods were applied to the fault rocks, organic matter and quaternary formations collected from the Pyeonghae, Bogyeongsa, Yugyeri, Byegkye, Gacheon-1 and Joil outcrops of the Yangsan fault system, the Baenaegol outcrop of the Moryang fault system, the Susyongji(Madong-2), Singye, Hwalseongri, Ipsil and Wonwonsa outcrops of the Ulsan fault system and from quaternary marine terraces (Oryoo and Kwangseong sites) in the southeastern coastal area. The experimental procedure of the OSL SAR protocol was reexamined to get more reliable dating results.

  2. All-optical conversion scheme: Binary to quaternary and quaternary to binary number

    Science.gov (United States)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2009-04-01

    To achieve the inherent parallelism in optics a suitable number system and efficient encoding/decoding scheme for handling the data are very much essential. Binary number is accepted as the best representing number system in almost all types of existing electronic computers. But, binary number (0 and 1) is insufficient in respect to the demand of the coming generation. Multi-valued logic (with radix >2) can be viewed as an alternative approach to solve many problems in transmission, storage and processing of large amount of information in digital signal processing. Here, in this paper all-optical scheme for the conversion of binary to quaternary number and vice versa have been proposed and described. Simulation has also been done. In this all-optical scheme the numbers are represented by different discrete polarized state of light.

  3. Characterization of Quaternary and suspected Quaternary faults, Amargosa area, Nevada and California

    International Nuclear Information System (INIS)

    Anderson, R.E.; Crone, A.J.; Machette, M.N.; Bradley, L.A.; Diehl, S.F.

    1995-01-01

    This report presents the results of geologic studies that help define the Quaternary history of selected faults in the region around Yucca Mountain, Nevada. These results are relevant to the seismic-design basis of a potential nuclear waste repository at Yucca Mountain. The relevancy is based, in part, on a need for additional geologic data that became apparent in ongoing studies by S. Pezzopane (written commun., 1995) that resulted in the identification of 51 relevant and potentially relevant (see appendix A for definitions) individual and compound faults and fault zones in the 100-km-radius region around the Yucca Mountain site. These structures were divided into local and regional categories by Pezzopane (1995); this report deals with selected regional structures. In this introduction, the authors outline the scope and strategy of the studies and the tectonic environment of the studied structures

  4. Characterization of Quaternary and suspected Quaternary faults, Amargosa area, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.E.; Crone, A.J.; Machette, M.N.; Bradley, L.A.; Diehl, S.F.

    1995-12-31

    This report presents the results of geologic studies that help define the Quaternary history of selected faults in the region around Yucca Mountain, Nevada. These results are relevant to the seismic-design basis of a potential nuclear waste repository at Yucca Mountain. The relevancy is based, in part, on a need for additional geologic data that became apparent in ongoing studies by S. Pezzopane (written commun., 1995) that resulted in the identification of 51 relevant and potentially relevant (see appendix A for definitions) individual and compound faults and fault zones in the 100-km-radius region around the Yucca Mountain site. These structures were divided into local and regional categories by Pezzopane (1995); this report deals with selected regional structures. In this introduction, the authors outline the scope and strategy of the studies and the tectonic environment of the studied structures.

  5. Quaternary geologic map of the Austin 4° x 6° quadrangle, United States

    Science.gov (United States)

    State compilations by Moore, David W.; Wermund, E.G.; edited and integrated by Moore, David W.; Richmond, Gerald Martin; Christiansen, Ann Coe; Bush, Charles A.

    1993-01-01

    This map is part of the Quaternary Geologic Atlas of the United States (I-1420). It was first published as a printed edition in 1993. The geologic data have now been captured digitally and are presented here along with images of the printed map sheet and component parts as PDF files. The Quaternary Geologic Map of the Austin 4° x 6° Quadrangle was mapped as part of the Quaternary Geologic Atlas of the United States. The atlas was begun as an effort to depict the areal distribution of surficial geologic deposits and other materials that accumulated or formed during the past 2+ million years, the period that includes all activities of the human species. These materials are at the surface of the Earth. They make up the ground on which we walk, the dirt in which we dig foundations, and the soil in which we grow crops. Most of our human activity is related in one way or another to these surface materials that are referred to collectively by many geologists as regolith, the mantle of fragmental and generally unconsolidated material that overlies the bedrock foundation of the continent. The maps were compiled at 1:1,000,000 scale. In recent years, surficial deposits and materials have become the focus of much interest by scientists, environmentalists, governmental agencies, and the general public. They are the foundations of ecosystems, the materials that support plant growth and animal habitat, and the materials through which travels much of the water required for our agriculture, our industry, and our general well being. They also are materials that easily can become contaminated by pesticides, fertilizers, and toxic wastes. In this context, the value of the surficial geologic map is evident.

  6. Temperature influences selective mortality during the early life stages of a coral reef fish.

    Directory of Open Access Journals (Sweden)

    Tauna L Rankin

    2011-05-01

    Full Text Available For organisms with complex life cycles, processes occurring at the interface between life stages can disproportionately impact survival and population dynamics. Temperature is an important factor influencing growth in poikilotherms, and growth-related processes are frequently correlated with survival. We examined the influence of water temperature on growth-related early life history traits (ELHTs and differential mortality during the transition from larval to early juvenile stage in sixteen monthly cohorts of bicolor damselfish Stegastes partitus, sampled on reefs of the upper Florida Keys, USA over 6 years. Otolith analysis of settlers and juveniles coupled with environmental data revealed that mean near-reef water temperature explained a significant proportion of variation in pelagic larval duration (PLD, early larval growth, size-at-settlement, and growth during early juvenile life. Among all cohorts, surviving juveniles were consistently larger at settlement, but grew more slowly during the first 6 d post-settlement. For the other ELHTs, selective mortality varied seasonally: during winter and spring months, survivors exhibited faster larval growth and shorter PLDs, whereas during warmer summer months, selection on PLD reversed and selection on larval growth became non-linear. Our results demonstrate that temperature not only shapes growth-related traits, but can also influence the direction and intensity of selective mortality.

  7. Benthic reef primary production in response to large amplitude internal waves at the Similan Islands (Andaman Sea, Thailand)

    KAUST Repository

    Jantzen, Carin

    2013-11-29

    Coral reefs are facing rapidly changing environments, but implications for reef ecosystem functioning and important services, such as productivity, are difficult to predict. Comparative investigations on coral reefs that are naturally exposed to differing environmental settings can provide essential information in this context. One prevalent phenomenon regularly introducing alterations in water chemistry into coral reefs are internal waves. This study therefore investigates the effect of large amplitude internal waves (LAIW) on primary productivity in coral reefs at the Similan Islands (Andaman Sea, Thailand). The LAIW-exposed west sides of the islands are subjected to sudden drops in water temperature accompanied by enhanced inorganic nutrient concentrations compared to the sheltered east. At the central island, Ko Miang, east and west reefs are only few hundred meters apart, but feature pronounced differences. On the west lower live coral cover (-38%) coincides with higher turf algae cover (+64%) and growth (+54%) compared to the east side. Turf algae and the reef sand-associated microphytobenthos displayed similar chlorophyll a contents on both island sides, but under LAIW exposure, turf algae exhibited higher net photosynthesis (+23%), whereas the microphytobenthos displayed reduced net and gross photosynthesis (-19% and -26%, respectively) accompanied by lower respiration (-42%). In contrast, the predominant coral Porites lutea showed higher chlorophyll a tissues contents (+42%) on the LAIW-exposed west in response to lower light availability and higher inorganic nutrient concentrations, but net photosynthesis was comparable for both sides. Turf algae were the major primary producers on the west side, whereas microphytobenthos dominated on the east. The overall primary production rate (comprising all main benthic primary producers) was similar on both island sides, which indicates high primary production variability under different environmental conditions.

  8. Electrochemical oxidation of quaternary ammonium electrolytes : Unexpected side reactions in organic electrochemistry

    NARCIS (Netherlands)

    Nouri Nigjeh, Eslam; de Vries, Marcel; Bruins, Andries P.; Bischoff, Rainer; Permentier, Hjalmar P.

    Quaternary ammonium salts are among the most widely used electrolytes in organic electrochemistry, but there is little known about their unwanted side oxidation reactions. We have, therefore, studied the constant potential oxidation products of quaternary ammonium electrolytes using mass

  9. The Ecological Role of Sharks on Coral Reefs.

    Science.gov (United States)

    Roff, George; Doropoulos, Christopher; Rogers, Alice; Bozec, Yves-Marie; Krueck, Nils C; Aurellado, Eleanor; Priest, Mark; Birrell, Chico; Mumby, Peter J

    2016-05-01

    Sharks are considered the apex predator of coral reefs, but the consequences of their global depletion are uncertain. Here we explore the ecological roles of sharks on coral reefs and, conversely, the importance of reefs for sharks. We find that most reef-associated shark species do not act as apex predators but instead function as mesopredators along with a diverse group of reef fish. While sharks perform important direct and indirect ecological roles, the evidence to support hypothesised shark-driven trophic cascades that benefit corals is weak and equivocal. Coral reefs provide some functional benefits to sharks, but sharks do not appear to favour healthier reef environments. Restoring populations of sharks is important and can yet deliver ecological surprise. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. The continuing decline of coral reefs in Bahrain.

    Science.gov (United States)

    Burt, John A; Al-Khalifa, Khalifa; Khalaf, Ebtesam; Alshuwaikh, Bassem; Abdulwahab, Ahmed

    2013-07-30

    Historically coral reefs of Bahrain were among the most extensive in the southern basin of the Arabian Gulf. However, Bahrain's reefs have undergone significant decline in the last four decades as a result of large-scale coastal development and elevated sea surface temperature events. Here we quantitatively surveyed six sites including most major coral reef habitats around Bahrain and a reef located 72 km offshore. Fleshy and turf algae now dominate Bahrain's reefs (mean: 72% cover), and live coral cover is low (mean: 5.1%). Formerly dominant Acropora were not observed at any site. The offshore Bulthama reef had the highest coral cover (16.3%) and species richness (22 of the 23 species observed, 13 of which were exclusive to this site). All reefs for which recent and historical data are available show continued degradation, and it is unlikely that they will recover under continuing coastal development and projected climate change impacts. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. NOAA's Coral Reef Conservation Program: 2016 projects to address coral reef conservation issues

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 2016 the following projects will take place to address aspects of coral reef conservation: Enhancing Management of Pacific ESA-listed Corals with Improved Utility...

  12. Guam Long-term Coral Reef Monitoring Program Reef Fish Surveys since 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Government of Guam's Long-term Coral Reef Monitoring Program, coordinated by the Guam Coastal Management Program until October 2013 and now coordinated by the...

  13. Guam Long-term Coral Reef Monitoring Program Reef Fish Surveys FY2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Government of Guam's Long-term Coral Reef Monitoring Program, coordinated by the University of Guam Marine Lab, involves the collection of data for a suite of...

  14. NOAA's Coral Reef Conservation Program: Coral Reef Habitat Mapping Projects in 2016

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Maps are a critical cornerstone of coral reef management, research and planning, with direct links to management needs in a number of forms. To accurately...

  15. Radio-labelled quaternary compounds and their diagnostic use

    International Nuclear Information System (INIS)

    Woo, D.V.

    1984-01-01

    Radio-labelled compounds having a lipophilic cation, which are quaternary ammonium, phosphonium or arsonium halides, in which the halide is a chloride, bromide or iodide, and in which the four quaternary substituents are independently selected from Csub(1-3) alkyl, phenyl and benzyl, at least two substituents being phenyl or benzyl, and one phenyl or benzyl substituent carrying a ring-substituent selected from 123 I, 125 I, 131 I, 77 Br, 82 Br and 18 F. Such compounds can be administered by injection, and a radio-image of the myocardium obtained. (author)

  16. In situ coral reef oxygen metabolism: an eddy correlation study.

    Directory of Open Access Journals (Sweden)

    Matthew H Long

    Full Text Available Quantitative studies of coral reefs are challenged by the three-dimensional hard structure of reefs and the high spatial variability and temporal dynamics of their metabolism. We used the non-invasive eddy correlation technique to examine respiration and photosynthesis rates, through O2 fluxes, from reef crests and reef slopes in the Florida Keys, USA. We assessed how the photosynthesis and respiration of different reef habitats is controlled by light and hydrodynamics. Numerous fluxes (over a 0.25 h period were as high as 4500 mmol O2 m(-2 d(-1, which can only be explained by efficient light utilization by the phototrophic community and the complex canopy structure of the reef, having a many-fold larger surface area than its horizontal projection. Over diel cycles, the reef crest was net autotrophic, whereas on the reef slope oxygen production and respiration were balanced. The autotrophic nature of the shallow reef crests implies that the export of organics is an important source of primary production for the larger area. Net oxygen production on the reef crest was proportional to the light intensity, up to 1750 µmol photons m(-2 s(-1 and decreased thereafter as respiration was stimulated by high current velocities coincident with peak light levels. Nighttime respiration rates were also stimulated by the current velocity, through enhanced ventilation of the porous framework of the reef. Respiration rates were the highest directly after sunset, and then decreased during the night suggesting that highly labile photosynthates produced during the day fueled early-night respiration. The reef framework was also important to the acquisition of nutrients as the ambient nitrogen stock in the water had sufficient capacity to support these high production rates across the entire reef width. These direct measurements of complex reefs systems yielded high metabolic rates and dynamics that can only be determined through in situ, high temporal resolution

  17. Reef sharks: recent advances in ecological understanding to inform conservation.

    Science.gov (United States)

    Osgood, G J; Baum, J K

    2015-12-01

    Sharks are increasingly being recognized as important members of coral-reef communities, but their overall conservation status remains uncertain. Nine of the 29 reef-shark species are designated as data deficient in the IUCN Red List, and three-fourths of reef sharks had unknown population trends at the time of their assessment. Fortunately, reef-shark research is on the rise. This new body of research demonstrates reef sharks' high site restriction, fidelity and residency on coral reefs, their broad trophic roles connecting reef communities and their high population genetic structure, all information that should be useful for their management and conservation. Importantly, recent studies on the abundance and population trends of the three classic carcharhinid reef sharks (grey reef shark Carcharhinus amblyrhynchos, blacktip reef shark Carcharhinus melanopterus and whitetip reef shark Triaenodon obesus) may contribute to reassessments identifying them as more vulnerable than currently realized. Because over half of the research effort has focused on only these three reef sharks and the nurse shark Ginglymostoma cirratum in only a few locales, there remain large taxonomic and geographic gaps in reef-shark knowledge. As such, a large portion of reef-shark biodiversity remains uncharacterized despite needs for targeted research identified in their red list assessments. A research agenda for the future should integrate abundance, life history, trophic ecology, genetics, habitat use and movement studies, and expand the breadth of such research to understudied species and localities, in order to better understand the conservation requirements of these species and to motivate effective conservation solutions. © 2015 The Fisheries Society of the British Isles.

  18. Environmental controls of coral growth: Data driven multi-scale analyses of rates and patterns of growth in massive Porites corals around the Thai-Malay Peninsula

    NARCIS (Netherlands)

    Tanzil, J.T.I.

    2013-01-01

    Scleractinian corals produce large amounts of calcium carbonate as they grow, sustaining the three-dimensional reef framework that supports the high productivity and biodiversity associated with tropical coral reefs. The rate of skeletal growth of corals is therefore not only essential for their

  19. Diving down the reefs? Intensive diving tourism threatens the reefs of the northern Red Sea.

    Science.gov (United States)

    Hasler, Harald; Ott, Jörg A

    2008-10-01

    Intensive recreational SCUBA diving threatens coral reef ecosystems. The reefs at Dahab, South Sinai, Egypt, are among the world's most dived (>30,000 dives y(-1)). We compared frequently dived sites to sites with no or little diving. Benthic communities and condition of corals were examined by the point intercept sampling method in the reef crest zone (3m) and reef slope zone (12 m). Additionally, the abundance of corallivorous and herbivorous fish was estimated based on the visual census method. Sediments traps recorded the sedimentation rates caused by SCUBA divers. Zones subject to intensive SCUBA diving showed a significantly higher number of broken and damaged corals and significantly lower coral cover. Reef crest coral communities were significantly more affected than those of the reef slope: 95% of the broken colonies were branching ones. No effect of diving on the abundance of corallivorous and herbivorous fish was evident. At heavily used dive sites, diver-related sedimentation rates significantly decreased with increasing distance from the entrance, indicating poor buoyancy regulation at the initial phase of the dive. The results show a high negative impact of current SCUBA diving intensities on coral communities and coral condition. Corallivorous and herbivorous fishes are apparently not yet affected, but are endangered if coral cover decline continues. Reducing the number of dives per year, ecologically sustainable dive plans for individual sites, and reinforcing the environmental education of both dive guides and recreational divers are essential to conserve the ecological and the aesthetic qualities of these dive sites.

  20. Coral Reefs: An English Compilation of Activities for Middle School Students.

    Science.gov (United States)

    Walker, Sharon H.; Newton, R. Amanda; Ortiz, Alida

    This activity book on coral reefs for middle school students is divided into 10 sections. Section 1 contains the introduction. Section 2 describes what coral reefs are while section 3 describes how coral reefs reproduce and grow. Section 4 discusses where coral reefs are found and section 5 describes life on a coral reef. Section 6 discusses the…

  1. The effects of trophic interactions and spatial competition on algal community composition on Hawaiian coral reefs

    NARCIS (Netherlands)

    Vermeij, M.J.A.; Dailer, M.L.; Walsh, S.M.; Donovan, M.K.; Smith, C.M.

    2010-01-01

    Much of coral reef ecology has focused on how human impacts change coral reefs to macroalgal reefs. However, macroalgae may not always be a good indicator of reef decline, especially on reefs with significant sea urchin populations, as found in Kenya and Hawaii. This study tests the effects of

  2. Mola'a Revisited: Reef Panpipes

    DEFF Research Database (Denmark)

    2017-01-01

    The first main shoot for the Reef Islands Ethnographic Film Series in the Solomon Islands, in 1996, was seriously affected by the un- expected death of one of the main characters and partners in the project, Alfred Melotu, the paramount chief of the Aiwoo-speaking people on the island of Ngasinue...

  3. Sensing coral reef connectivity pathways from space

    KAUST Repository

    Raitsos, Dionysios E.; Brewin, Robert J. W.; Zhan, Peng; Dreano, Denis; Pradhan, Yaswant; Nanninga, Gerrit B.; Hoteit, Ibrahim

    2017-01-01

    Coral reefs rely on inter-habitat connectivity to maintain gene flow, biodiversity and ecosystem resilience. Coral reef communities of the Red Sea exhibit remarkable genetic homogeneity across most of the Arabian Peninsula coastline, with a genetic break towards the southern part of the basin. While previous studies have attributed these patterns to environmental heterogeneity, we hypothesize that they may also emerge as a result of dynamic circulation flow; yet, such linkages remain undemonstrated. Here, we integrate satellite-derived biophysical observations, particle dispersion model simulations, genetic population data and ship-borne in situ profiles to assess reef connectivity in the Red Sea. We simulated long-term (>20 yrs.) connectivity patterns driven by remotely-sensed sea surface height and evaluated results against estimates of genetic distance among populations of anemonefish, Amphiprion bicinctus, along the eastern Red Sea coastline. Predicted connectivity was remarkably consistent with genetic population data, demonstrating that circulation features (eddies, surface currents) formulate physical pathways for gene flow. The southern basin has lower physical connectivity than elsewhere, agreeing with known genetic structure of coral reef organisms. The central Red Sea provides key source regions, meriting conservation priority. Our analysis demonstrates a cost-effective tool to estimate biophysical connectivity remotely, supporting coastal management in data-limited regions.

  4. Shellfish reef restoration pilots: Voordelta The Netherlands

    NARCIS (Netherlands)

    Sas, H.; Kamermans, P.; Have, van der T.M.; Lengkeek, W.; Smaal, A.C.

    2016-01-01

    Once, shellfish reefs - mainly flat oysters - covered about 20% of the North Sea floor, but diseases, pollution and overfishing have led to a significant decline. As part of the Haringvliet Dream Fund Project (www.haringvliet.nu), ARK
    Nature and World Wildlife Fund Netherlands are working on

  5. Water Quality Standards for Coral Reef Protection

    Science.gov (United States)

    The U.S. Clean Water Act provides a legal framework to protect coastal biological resources such as coral reefs, mangrove forests, and seagrass meadows from the damaging effects of human activities. Even though many resources are protected under this authority, water quality stan...

  6. North Jamaican Deep Fore-Reef Sponges

    NARCIS (Netherlands)

    Lehnert, Helmut; Soest, van R.W.M.

    1996-01-01

    An unexpectedly high amount of new species, revealed within only one hour of summarized bottom time, leads to the conclusion that the sponge fauna of the steep slopes of the deep fore-reef is still largely unknown. Four mixed gas dives at depths between 70 and 90 m, performed in May and June, 1993,

  7. Sensing coral reef connectivity pathways from space

    KAUST Repository

    Raitsos, Dionysios E.

    2017-08-18

    Coral reefs rely on inter-habitat connectivity to maintain gene flow, biodiversity and ecosystem resilience. Coral reef communities of the Red Sea exhibit remarkable genetic homogeneity across most of the Arabian Peninsula coastline, with a genetic break towards the southern part of the basin. While previous studies have attributed these patterns to environmental heterogeneity, we hypothesize that they may also emerge as a result of dynamic circulation flow; yet, such linkages remain undemonstrated. Here, we integrate satellite-derived biophysical observations, particle dispersion model simulations, genetic population data and ship-borne in situ profiles to assess reef connectivity in the Red Sea. We simulated long-term (>20 yrs.) connectivity patterns driven by remotely-sensed sea surface height and evaluated results against estimates of genetic distance among populations of anemonefish, Amphiprion bicinctus, along the eastern Red Sea coastline. Predicted connectivity was remarkably consistent with genetic population data, demonstrating that circulation features (eddies, surface currents) formulate physical pathways for gene flow. The southern basin has lower physical connectivity than elsewhere, agreeing with known genetic structure of coral reef organisms. The central Red Sea provides key source regions, meriting conservation priority. Our analysis demonstrates a cost-effective tool to estimate biophysical connectivity remotely, supporting coastal management in data-limited regions.

  8. Climate change impacts on coral reefs: synergies with local effects, possibilities for acclimation, and management implications.

    Science.gov (United States)

    Ateweberhan, Mebrahtu; Feary, David A; Keshavmurthy, Shashank; Chen, Allen; Schleyer, Michael H; Sheppard, Charles R C

    2013-09-30

    Most reviews concerning the impact of climate change on coral reefs discuss independent effects of warming or ocean acidification. However, the interactions between these, and between these and direct local stressors are less well addressed. This review underlines that coral bleaching, acidification, and diseases are expected to interact synergistically, and will negatively influence survival, growth, reproduction, larval development, settlement, and post-settlement development of corals. Interactions with local stress factors such as pollution, sedimentation, and overfishing are further expected to compound effects of climate change. Reduced coral cover and species composition following coral bleaching events affect coral reef fish community structure, with variable outcomes depending on their habitat dependence and trophic specialisation. Ocean acidification itself impacts fish mainly indirectly through disruption of predation- and habitat-associated behavior changes. Zooxanthellate octocorals on reefs are often overlooked but are substantial occupiers of space; these also are highly susceptible to bleaching but because they tend to be more heterotrophic, climate change impacts mainly manifest in terms of changes in species composition and population structure. Non-calcifying macroalgae are expected to respond positively to ocean acidification and promote microbe-induced coral mortality via the release of dissolved compounds, thus intensifying phase-shifts from coral to macroalgal domination. Adaptation of corals to these consequences of CO2 rise through increased tolerance of corals and successful mutualistic associations between corals and zooxanthellae is likely to be insufficient to match the rate and frequency of the projected changes. Impacts are interactive and magnified, and because there is a limited capacity for corals to adapt to climate change, global targets of carbon emission reductions are insufficient for coral reefs, so lower targets should be

  9. The engine of the reef: Photobiology of the coral-algal symbiosis

    Directory of Open Access Journals (Sweden)

    Melissa Susan Roth

    2014-08-01

    Full Text Available Coral reef ecosystems thrive in tropical oligotrophic oceans because of the relationship between corals and endosymbiotic dinoflagellate algae called Symbiodinium. Symbiodinium convert sunlight and carbon dioxide into organic carbon and oxygen to fuel coral growth and calcification, creating habitat for these diverse and productive ecosystems. Light is thus a key regulating factor shaping the productivity, physiology and ecology of the coral holobiont. Similar to all oxygenic photoautotrophs, Symbiodinium must safely harvest sunlight for photosynthesis and dissipate excess energy to prevent oxidative stress. Oxidative stress is caused by environmental stressors such as those associated with global climate change, and ultimately leads to breakdown of the coral-algal symbiosis known as coral bleaching. Recently, large-scale coral bleaching events have become pervasive and frequent threatening and endangering coral reefs. Because the coral-algal symbiosis is the biological engine producing the reef, the future of coral reef ecosystems depends on the ecophysiology of the symbiosis. This review examines the photobiology of the coral-algal symbiosis with particular focus on the photophysiological responses and timescales of corals and Symbiodinium. Additionally, this review summarizes the light environment and its dynamics, the vulnerability of the symbiosis to oxidative stress, the abiotic and biotic factors influencing photosynthesis, the diversity of the coral-algal symbiosis and recent advances in the field. Studies integrating physiology with the developing omics fields will provide new insights into the coral-algal symbiosis. Greater physiological and ecological understanding of the coral-algal symbiosis is needed for protection and conservation of coral reefs.

  10. The engine of the reef: photobiology of the coral–algal symbiosis

    Science.gov (United States)

    Roth, Melissa S.

    2014-01-01

    Coral reef ecosystems thrive in tropical oligotrophic oceans because of the relationship between corals and endosymbiotic dinoflagellate algae called Symbiodinium. Symbiodinium convert sunlight and carbon dioxide into organic carbon and oxygen to fuel coral growth and calcification, creating habitat for these diverse and productive ecosystems. Light is thus a key regulating factor shaping the productivity, physiology, and ecology of the coral holobiont. Similar to all oxygenic photoautotrophs, Symbiodinium must safely harvest sunlight for photosynthesis and dissipate excess energy to prevent oxidative stress. Oxidative stress is caused by environmental stressors such as those associated with global climate change, and ultimately leads to breakdown of the coral–algal symbiosis known as coral bleaching. Recently, large-scale coral bleaching events have become pervasive and frequent threatening and endangering coral reefs. Because the coral–algal symbiosis is the biological engine producing the reef, the future of coral reef ecosystems depends on the ecophysiology of the symbiosis. This review examines the photobiology of the coral–algal symbiosis with particular focus on the photophysiological responses and timescales of corals and Symbiodinium. Additionally, this review summarizes the light environment and its dynamics, the vulnerability of the symbiosis to oxidative stress, the abiotic and biotic factors influencing photosynthesis, the diversity of the coral–algal symbiosis, and recent advances in the field. Studies integrating physiology with the developing “omics” fields will provide new insights into the coral–algal symbiosis. Greater physiological and ecological understanding of the coral–algal symbiosis is needed for protection and conservation of coral reefs. PMID:25202301

  11. The Quaternary Environmental Change in the Northeast of Quintana Roo, Mexico:The Paleopedological Proxies

    Science.gov (United States)

    Cabadas Báez, H. V.; Sedov, S.; Solleiro Rebolledo, E.

    2010-03-01

    The Yucatán Peninsula, located in the southeast part of Mexico, is characterized to be an extended and low altitude platform constituted by calcareous rocks. These rocks are mainly limestones formed since Cretaceous under a marine shelf environment. In the northeast coast, the youngest sediments are found, as products of Quaternary sea level changes. We studied various profiles in quarries, following north-south transect in the Yucatan coast, near Cancún. In such profiles a sequence consisting of different kind of calcareous sediments and a soil in the surface were analyzed. The base of the sequence is constituted by a petrocalcic horizon (calcrete) that was formed during the last interglacial, 125,000 yrs. ago. Under the calcrete, a transgressive sequence appears with calcareous sediments of lagoon and reef facies. The uppermost part consists of dune-like sediments with crossed stratification overlied by another petrocalcic horizon, maybe formed during the Pleistocene-Holocene transition. Soils of the Yucatan Peninsula are very thin, rich in organic matter, neutral and well structured, and their image do not correspond to that found in tropical soils (deep, strongly weathered, leached). They are directly associated with the dune sediment dissolution because are infilling the "space" generated by rock dissolution. Calcrete is always in the uppermost part, but is broken and crossed by soil. This sequence reveals some aspects of the environmental dynamic during Late Pleistocene-Holocene. First, a dryer environment is assumed due to the presence of the calcrete in the base. During the glacial period, a transgressive environment prevailed and marine calcareous sedimentation started. During Last Glacial Maximum a regression occurred, the climate was drier and the formation of dune sediments and another calcrete occurred. In the Holocene climate changed shifting toward more humid conditions that produced the modern soil cover, under tropical conditions.

  12. Modelling coral reef futures to inform management: can reducing local-scale stressors conserve reefs under climate change?

    Science.gov (United States)

    Gurney, Georgina G; Melbourne-Thomas, Jessica; Geronimo, Rollan C; Aliño, Perry M; Johnson, Craig R

    2013-01-01

    Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing) might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao's reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao's reef system, our study offers insights which could inform reef management more broadly, as well as general understanding of reef

  13. Modelling coral reef futures to inform management: can reducing local-scale stressors conserve reefs under climate change?

    Directory of Open Access Journals (Sweden)

    Georgina G Gurney

    Full Text Available Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao's reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao's reef system, our study offers insights which could inform reef management more broadly, as well as general

  14. Correlation Between Existence of Reef Sharks with Abundance of Reef Fishes in South Waters of Morotai Island (North Moluccas)

    Science.gov (United States)

    Mukharror, Darmawan Ahmad; Tiara Baiti, Isnaini; Ichsan, Muhammad; Pridina, Niomi; Triutami, Sanny

    2017-10-01

    Despite increasing academic research citation on biology, abundance, and the behavior of the blacktip reef sharks, the influence of reef fish population on the density of reef sharks: Carcharhinus melanopterus and Triaenodon obesus population in its habitat were largely unassessed. This present study examined the correlation between abundance of reef fishes family/species with the population of reef sharks in Southern Waters of Morotai Island. The existence of reef sharks was measured with the Audible Stationary Count (ASC) methods and the abundance of reef fishes was surveyed using Underwater Visual Census (UVC) combined with Diver Operated Video (DOV) census. The coefficient of Determination (R2) was used to investigate the degree of relationships between sharks and the specific reef fishes species. The research from 8th April to 4th June 2015 showed the strong positive correlations between the existence of reef sharks with abundance of reef fishes. The correlation values between Carcharhinus melanopterus/Triaenodon obesus with Chaetodon auriga was 0.9405, blacktip/whitetip reef sharks versus Ctenochaetus striatus was 0.9146, and Carcharhinus melanopterus/Triaenodon obesus to Chaetodon kleinii was 0.8440. As the shark can be worth more alive for shark diving tourism than dead in a fish market, the abundance of these reef fishes was important as an early indication parameter of shark existence in South Water of Morotai Island. In the long term, this highlights the importance of reef fishes abundance management in Morotai Island’s Waters to enable the establishment of appropriate and effective reef sharks conservation.

  15. Modelling Coral Reef Futures to Inform Management: Can Reducing Local-Scale Stressors Conserve Reefs under Climate Change?

    Science.gov (United States)

    Gurney, Georgina G.; Melbourne-Thomas, Jessica; Geronimo, Rollan C.; Aliño, Perry M.; Johnson, Craig R.

    2013-01-01

    Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing) might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao's reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao's reef system, our study offers insights which could inform reef management more broadly, as well as general understanding of reef

  16. Doxycycline and its quaternary ammonium derivative for adjuvant therapies of chondrosarcoma.

    Science.gov (United States)

    Miladi, Imen; Vivier, Magali; Dauplat, Marie-Mélanie; Chatard, Morgane; Besse, Sophie; Vidal, Aurélien; Chassain, Karine; Jean, Betty; Forestier, Christiane; Chezal, Jean-Michel; Rédini, Francoise; Degoul, Francoise; Miot-Noirault, Elisabeth

    2017-09-01

    This study was conducted during the development of innovative treatment targeting the microenvironment of chondrosarcoma. In this context, MMP inhibitors were conjugated with a quaternary ammonium (QA) function as a targeting ligand to proteoglycans of chondrosarcoma extracellular matrix. Here we report the proof of concept of this strategy applied to the MMP13 inhibitor, doxycycline (Dox). A quaternary ammonium derivative of the MMP13 inhibitor doxycycline (QA-Dox) was synthesized, and its anticancer activity was evaluated in the Swarm rat chondrosarcoma (SRC) model compared with the parent drug doxycycline, in vitro and in vivo. In vivo, dox and QA-Dox efficiency was assessed at equimolar doses according to a q4dx4 schedule by monitoring tumour volume by MRI and PG-targeted scintigraphy. Molecular mechanism (MMP13 expression, proteoglycan level) and histology studies were performed on tumours. The link of QA targeting function to Dox maintained the MMP13 inhibitory activity in vitro. Interestingly, the bacteriostatic activity was lost. SRC cells incubated with both drugs were blocked in S and G2 M phases. Tumour growth inhibition (confirmed by histology) was observed for both Dox and QA-Dox. Undesirable blood effects (leukocyte decrease) were reduced when Dox was targeted to tumour tissue using the QA function. In the SRC model, the MMP13 inhibitor Dox and its QA derivative are promising as adjuvant therapies for chondrosarcoma management.

  17. Magmatic sulphides in Quaternary Ecuadorian arc magmas

    Science.gov (United States)

    Georgatou, Ariadni; Chiaradia, Massimo; Rezeau, Hervé; Wälle, Markus

    2018-01-01

    New petrographic and geochemical data on magmatic sulphide inclusions (MSIs) are presented and discussed for 15 Quaternary volcanic centers of the Ecuadorian frontal, main and back volcanic arc. MSIs occur mostly in Fe-Ti oxides (magnetite and/or magnetite-ilmenite pair) and to a lesser extent in silicate minerals (amphibole, plagioclase, and pyroxene). MSIs are present in all volcanic centers ranging in composition from basalt to dacite (SiO2 = 50-67 wt.%), indicating that sulphide saturation occurs at various stages of magmatic evolution and independently from the volcano location along the volcanic arc. MSIs also occur in dioritic, gabbroic and hornblenditic magmatic enclaves of the volcanic rocks. MSIs display variable sizes (1-30 μm) and shapes (globular, ellipsoidal, angular, irregular) and occur mostly as polymineralic inclusions composed of Fe-rich and Cu-poor (pyrrhotite) and Cu-rich (mostly chalcopyrite) phases. Aerial sulphide relative abundances range from 0.3 to 7 ppm in volcanic host rocks and from 13 to 24 ppm in magmatic enclaves. Electron microprobe analyses of MSIs indicate maximum metal contents of Cu = 65.7 wt.%, Fe = 65.2 wt.%, Ni = 10.1 wt.% for those hosted in the volcanic rocks and of Cu = 57.7 wt.%, Fe = 60.9 wt.%, Ni = 5.1 wt.%, for those hosted in magmatic enclaves. Relationships of the sulphide chemistry to the host whole rock chemistry show that with magmatic differentiation (e.g., increasing SiO2) the Cu and Ni content of sulphides decrease whereas the Fe and S contents increase. The opposite behavior is observed with the increase of Cu in the whole rock, because the latter is anti-correlated with the SiO2 whole rock content. Laser ablation ICP-MS analyses of MSIs returned maximum values of PGEs and noble metals of Pd = 30 ppm, Rh = 8.1 ppm, Ag = 92.8 ppm and Au = 0.6 ppm and Pd = 43 ppm, Rh = 22.6 ppm, Ag = 89 ppm and Au = 1 ppm for those hosted in volcanic rocks and magmatic enclaves, respectively. These PGE contents display a

  18. Global warming transforms coral reef assemblages.

    Science.gov (United States)

    Hughes, Terry P; Kerry, James T; Baird, Andrew H; Connolly, Sean R; Dietzel, Andreas; Eakin, C Mark; Heron, Scott F; Hoey, Andrew S; Hoogenboom, Mia O; Liu, Gang; McWilliam, Michael J; Pears, Rachel J; Pratchett, Morgan S; Skirving, William J; Stella, Jessica S; Torda, Gergely

    2018-04-01

    Global warming is rapidly emerging as a universal threat to ecological integrity and function, highlighting the urgent need for a better understanding of the impact of heat exposure on the resilience of ecosystems and the people who depend on them 1 . Here we show that in the aftermath of the record-breaking marine heatwave on the Great Barrier Reef in 2016 2 , corals began to die immediately on reefs where the accumulated heat exposure exceeded a critical threshold of degree heating weeks, which was 3-4 °C-weeks. After eight months, an exposure of 6 °C-weeks or more drove an unprecedented, regional-scale shift in the composition of coral assemblages, reflecting markedly divergent responses to heat stress by different taxa. Fast-growing staghorn and tabular corals suffered a catastrophic die-off, transforming the three-dimensionality and ecological functioning of 29% of the 3,863 reefs comprising the world's largest coral reef system. Our study bridges the gap between the theory and practice of assessing the risk of ecosystem collapse, under the emerging framework for the International Union for Conservation of Nature (IUCN) Red List of Ecosystems 3 , by rigorously defining both the initial and collapsed states, identifying the major driver of change, and establishing quantitative collapse thresholds. The increasing prevalence of post-bleaching mass mortality of corals represents a radical shift in the disturbance regimes of tropical reefs, both adding to and far exceeding the influence of recurrent cyclones and other local pulse events, presenting a fundamental challenge to the long-term future of these iconic ecosystems.

  19. Minimal erosion of Arctic alpine topography during late Quaternary glaciation

    Science.gov (United States)

    Gjermundsen, Endre F.; Briner, Jason P.; Akçar, Naki; Foros, Jørn; Kubik, Peter W.; Salvigsen, Otto; Hormes, Anne

    2015-10-01

    The alpine topography observed in many mountainous regions is thought to have formed during repeated glaciations of the Quaternary period. Before this time, landscapes had much less relief. However, the spatial patterns and rates of Quaternary exhumation at high latitudes--where cold-based glaciers may protect rather than erode landscapes--are not fully quantified. Here we determine the exposure and burial histories of rock samples from eight summits of steep alpine peaks in northwestern Svalbard (79.5° N) using analyses of 10Be and 26Al concentrations. We find that the summits have been preserved for at least the past one million years. The antiquity of Svalbard’s alpine landscape is supported by the preservation of sediments older than one million years along a fjord valley, which suggests that both mountain summits and low-elevation landscapes experienced very low erosion rates over the past million years. Our findings support the establishment of northwestern Svalbard’s alpine topography during the early Quaternary. We suggest that, as the Quaternary ice age progressed, glacial erosion in the Arctic became inefficient and confined to ice streams, and high-relief alpine landscapes were preserved by minimally erosive glacier armour.

  20. Late Quaternary changes in surface productivity and oxygen ...

    Indian Academy of Sciences (India)

    University of Allahabad, Allahabad 211 002, India. ∗ e-mail: ... This process lowers the pH of water which results into increased dissolution of ..... causes a rapid melting of the inland glaciers, an .... Quaternary climate changes; J. Atmos. Sci.

  1. Late Quaternary sea level and environmental changes from relic ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Keywords. Late Quaternary sea level; western margin of India; subsidence; uplift; depositional environment. ...... sea level rise by about 80m (between 12,000 and. 7,000 yr BP) or, .... from the Florida Keys; Palaentology 28 189–206. Carballo ...

  2. Integrating Quaternary science research in land management, restoration, and conservation

    Science.gov (United States)

    C.I. Millar; W.B. Woolfenden

    2001-01-01

    Most of us have come to expect that the general public will ignore the primary message of Quaternary science that change happens. A flurry, however, of recent media attention to 20th-century global warming and its anomalies from climates of the last millennium has brought climate science at least momentarily into popular focus. Similarly, public land-managing agencies...

  3. Quaternary climate changes explain diversity among reptiles and amphibians

    DEFF Research Database (Denmark)

    Bastos Araujo, Miguel; Nogués-Bravo, David; Diniz-Filho, Alexandre F.

    2008-01-01

    debated without reaching consensus. Here, we test the proposition that European species richness of reptiles and amphibians is driven by climate changes in the Quaternary. We find that climate stability between the Last Glacial Maximum (LGM) and the present day is a better predictor of species richness...

  4. Electron paramagnetic resonance: A new method of quaternary dating

    International Nuclear Information System (INIS)

    Poupeau, G.; Rossi, A.; Teles, M.M.; Danon, J.

    1984-01-01

    Significant progress has occurred in the last years in quaternary geochronology. One of this is the emergence of a new dating approach, the Electron Spin Resonance Method. The aim of this paper is to briefly review the method and discuss some aspects of the work at CBPF. (Author) [pt

  5. Electron paramagnetic resonance: a new method of quaternary dating

    International Nuclear Information System (INIS)

    Poupeau, G.; Rossi, A.; Universidade Federal Rural do Rio de Janeiro; Telles, M.; Danon, J.

    1984-01-01

    Significant progress has occurred in the last years in quaternary geochronology. One of this is the emergence of a new dating approach, the Electron Spin Resonance Method. The aim of this paper is to briefly review the method and discuss some aspects of the work at CBPF. (Author) [pt

  6. Fault control on patterns of Quaternary monogenetic vents in the ...

    African Journals Online (AJOL)

    Field and remote sensing data are used to examine the distribution of volcanism and fault geometry in the Ethiopian Rift between Omo-Chew Bahir rift and Tendaho graben during the Quaternary and evaluate their influence on the location and shape of individual vents as well as the development of alignments. The results ...

  7. Geo-Electric and Hydrogeochemical Mapping of Quaternary ...

    African Journals Online (AJOL)

    Michael Horsfall

    basically different from those observed in nearby Warri and indicative of possible ... exist in the Quaternary superficial deposits of the Niger Delta environment. ... the petroleum geology of the area has been subject of ... of Commerce and Industry, 2001; Atakpo and ... purposes of aquifer vulnerability assessments and the.

  8. A revision of the Pliocene and Quaternary Lutrinae from Europe

    NARCIS (Netherlands)

    Willemsen, G.F.

    1992-01-01

    In this paper, a revision of the Pliocene and Quaternary Lutrinae from Europe is presented. Such a revision, including fossil material, has not been published since the work of Pohle (1919). Three tribes within the Lutrinae are recognized: the Lutrini, the Aonyxini and the Enhydrini. The latter

  9. Fishing down the largest coral reef fish species.

    Science.gov (United States)

    Fenner, Douglas

    2014-07-15

    Studies on remote, uninhabited, near-pristine reefs have revealed surprisingly large populations of large reef fish. Locations such as the northwestern Hawaiian Islands, northern Marianas Islands, Line Islands, U.S. remote Pacific Islands, Cocos-Keeling Atoll and Chagos archipelago have much higher reef fish biomass than islands and reefs near people. Much of the high biomass of most remote reef fish communities lies in the largest species, such as sharks, bumphead parrots, giant trevally, and humphead wrasse. Some, such as sharks and giant trevally, are apex predators, but others such as bumphead parrots and humphead wrasse, are not. At many locations, decreases in large reef fish species have been attributed to fishing. Fishing is well known to remove the largest fish first, and a quantitative measure of vulnerability to fishing indicates that large reef fish species are much more vulnerable to fishing than small fish. The removal of large reef fish by fishing parallels the extinction of terrestrial megafauna by early humans. However large reef fish have great value for various ecological roles and for reef tourism. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. The role of turtles as coral reef macroherbivores

    KAUST Repository

    Goatley, Christopher H. R.

    2012-06-29

    Herbivory is widely accepted as a vital function on coral reefs. To date, the majority of studies examining herbivory in coral reef environments have focused on the roles of fishes and/or urchins, with relatively few studies considering the potential role of macroherbivores in reef processes. Here, we introduce evidence that highlights the potential role of marine turtles as herbivores on coral reefs. While conducting experimental habitat manipulations to assess the roles of herbivorous reef fishes we observed green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) showing responses that were remarkably similar to those of herbivorous fishes. Reducing the sediment load of the epilithic algal matrix on a coral reef resulted in a forty-fold increase in grazing by green turtles. Hawksbill turtles were also observed to browse transplanted thalli of the macroalga Sargassum swartzii in a coral reef environment. These responses not only show strong parallels to herbivorous reef fishes, but also highlight that marine turtles actively, and intentionally, remove algae from coral reefs. When considering the size and potential historical abundance of marine turtles we suggest that these potentially valuable herbivores may have been lost from many coral reefs before their true importance was understood. © 2012 Goatley et al.

  11. The role of turtles as coral reef macroherbivores

    KAUST Repository

    Goatley, Christopher H. R.; Hoey, Andrew; Bellwood, David R.

    2012-01-01

    Herbivory is widely accepted as a vital function on coral reefs. To date, the majority of studies examining herbivory in coral reef environments have focused on the roles of fishes and/or urchins, with relatively few studies considering the potential role of macroherbivores in reef processes. Here, we introduce evidence that highlights the potential role of marine turtles as herbivores on coral reefs. While conducting experimental habitat manipulations to assess the roles of herbivorous reef fishes we observed green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) showing responses that were remarkably similar to those of herbivorous fishes. Reducing the sediment load of the epilithic algal matrix on a coral reef resulted in a forty-fold increase in grazing by green turtles. Hawksbill turtles were also observed to browse transplanted thalli of the macroalga Sargassum swartzii in a coral reef environment. These responses not only show strong parallels to herbivorous reef fishes, but also highlight that marine turtles actively, and intentionally, remove algae from coral reefs. When considering the size and potential historical abundance of marine turtles we suggest that these potentially valuable herbivores may have been lost from many coral reefs before their true importance was understood. © 2012 Goatley et al.

  12. The role of turtles as coral reef macroherbivores.

    Directory of Open Access Journals (Sweden)

    Christopher H R Goatley

    Full Text Available Herbivory is widely accepted as a vital function on coral reefs. To date, the majority of studies examining herbivory in coral reef environments have focused on the roles of fishes and/or urchins, with relatively few studies considering the potential role of macroherbivores in reef processes. Here, we introduce evidence that highlights the potential role of marine turtles as herbivores on coral reefs. While conducting experimental habitat manipulations to assess the roles of herbivorous reef fishes we observed green turtles (Chelonia mydas and hawksbill turtles (Eretmochelys imbricata showing responses that were remarkably similar to those of herbivorous fishes. Reducing the sediment load of the epilithic algal matrix on a coral reef resulted in a forty-fold increase in grazing by green turtles. Hawksbill turtles were also observed to browse transplanted thalli of the macroalga Sargassum swartzii in a coral reef environment. These responses not only show strong parallels to herbivorous reef fishes, but also highlight that marine turtles actively, and intentionally, remove algae from coral reefs. When considering the size and potential historical abundance of marine turtles we suggest that these potentially valuable herbivores may have been lost from many coral reefs before their true importance was understood.

  13. Linking social and ecological systems to sustain coral reef fisheries.

    Science.gov (United States)

    Cinner, Joshua E; McClanahan, Timothy R; Daw, Tim M; Graham, Nicholas A J; Maina, Joseph; Wilson, Shaun K; Hughes, Terence P

    2009-02-10

    The ecosystem goods and services provided by coral reefs are critical to the social and economic welfare of hundreds of millions of people, overwhelmingly in developing countries [1]. Widespread reef degradation is severely eroding these goods and services, but the socioeconomic factors shaping the ways that societies use coral reefs are poorly understood [2]. We examine relationships between human population density, a multidimensional index of socioeconomic development, reef complexity, and the condition of coral reef fish populations in five countries across the Indian Ocean. In fished sites, fish biomass was negatively related to human population density, but it was best explained by reef complexity and a U-shaped relationship with socioeconomic development. The biomass of reef fishes was four times lower at locations with intermediate levels of economic development than at locations with both low and high development. In contrast, average biomass inside fishery closures was three times higher than in fished sites and was not associated with socioeconomic development. Sustaining coral reef fisheries requires an integrated approach that uses tools such as protected areas to quickly build reef resources while also building capacities and capital in societies over longer time frames to address the complex underlying causes of reef degradation.

  14. Re-creating missing population baselines for Pacific reef sharks.

    Science.gov (United States)

    Nadon, Marc O; Baum, Julia K; Williams, Ivor D; McPherson, Jana M; Zgliczynski, Brian J; Richards, Benjamin L; Schroeder, Robert E; Brainard, Russell E

    2012-06-01

    Sharks and other large predators are scarce on most coral reefs, but studies of their historical ecology provide qualitative evidence that predators were once numerous in these ecosystems. Quantifying density of sharks in the absence of humans (baseline) is, however, hindered by a paucity of pertinent time-series data. Recently researchers have used underwater visual surveys, primarily of limited spatial extent or nonstandard design, to infer negative associations between reef shark abundance and human populations. We analyzed data from 1607 towed-diver surveys (>1 ha transects surveyed by observers towed behind a boat) conducted at 46 reefs in the central-western Pacific Ocean, reefs that included some of the world's most pristine coral reefs. Estimates of shark density from towed-diver surveys were substantially lower (sharks observed in towed-diver surveys and human population in models that accounted for the influence of oceanic primary productivity, sea surface temperature, reef area, and reef physical complexity. We used these models to estimate the density of sharks in the absence of humans. Densities of gray reef sharks (Carcharhinus amblyrhynchos), whitetip reef sharks (Triaenodon obesus), and the group "all reef sharks" increased substantially as human population decreased and as primary productivity and minimum sea surface temperature (or reef area, which was highly correlated with temperature) increased. Simulated baseline densities of reef sharks under the absence of humans were 1.1-2.4/ha for the main Hawaiian Islands, 1.2-2.4/ha for inhabited islands of American Samoa, and 0.9-2.1/ha for inhabited islands in the Mariana Archipelago, which suggests that density of reef sharks has declined to 3-10% of baseline levels in these areas. ©2012 Society for Conservation Biology No claim to original US government works.

  15. A benthic survey of the rocky reefs off Pondoland, South Africa ...

    African Journals Online (AJOL)

    30m) in the ... the capture and processing of 1 042 photographic images of the reef benthos. ... reefs and suspension-feeding communities dominating deeper reefs. ... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  16. Resilience of coral reefs in the main Hawaiian Islands from 2013 to 2014 (NCEI Accession 0128219)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Declining health of coral reef ecosystems led scientists to search for factors that support reef resilience: the ability of reefs to resist and recover from...

  17. Widespread hybridization and bidirectional introgression in sympatric species of coral reef fish

    KAUST Repository

    Harrison, Hugo B.; Berumen, Michael L.; Saenz-Agudelo, Pablo; Salas, Eva; Williamson, David H.; Jones, Geoffrey P.

    2017-01-01

    interspecific hybrids from a collection of 2,991 coral trout sampled in inshore and mid-shelf reefs of the southern Great Barrier Reef. Hybrids were ubiquitous among reefs, fertile and spanned multiple generations suggesting both ecological and evolutionary

  18. Coral and artificial reef shape files, Broward County, Florida, (NODC Accession 0000244)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Coral reef and artificial reef location shape files and accompanying table files for reefs located off shore of Broward County, Florida. Accompanying "attribute"...

  19. Asymmetric competition prevents the outbreak of an opportunistic species after coral reef degradation.

    Science.gov (United States)

    González-Rivero, Manuel; Bozec, Yves-Marie; Chollett, Iliana; Ferrari, Renata; Schönberg, Christine H L; Mumby, Peter J

    2016-05-01

    Disturbance releases space and allows the growth of opportunistic species, excluded by the old stands, with a potential to alter community dynamics. In coral reefs, abundances of fast-growing, and disturbance-tolerant sponges are expected to increase and dominate as space becomes available following acute coral mortality events. Yet, an increase in abundance of these opportunistic species has been reported in only a few studies, suggesting certain mechanisms may be acting to regulate sponge populations. To gain insights into mechanisms of population control, we simulated the dynamics of the common reef-excavating sponge Cliona tenuis in the Caribbean using an individual-based model. An orthogonal hypothesis testing approach was used, where four candidate mechanisms-algal competition, stock-recruitment limitation, whole and partial mortality-were incorporated sequentially into the model and the results were tested against independent field observations taken over a decade in Belize, Central America. We found that releasing space after coral mortality can promote C. tenuis outbreaks, but such outbreaks can be curtailed by macroalgal competition. The asymmetrical competitive superiority of macroalgae, given by their capacity to pre-empt space and outcompete with the sponge in a size-dependant fashion, supports their capacity to steal the opportunity from other opportunists. While multiple system stages can be expected in coral reefs following intense perturbation macroalgae may prevent the growth of other space-occupiers, such as bioeroding sponges, under low grazing pressure.

  20. Novel tradable instruments in the conservation of coral reefs, based on the coral gardening concept for reef restoration.

    Science.gov (United States)

    Rinkevich, Baruch

    2015-10-01

    Nearly all coral reefs bordering nations have experienced net losses in reef biodiversity, goods and services, even without considering the ever-developing global change impacts. In response, this overview wishes to reveal through prospects of active reef-restoration, the currently non-marketed or poorly marketed reef services, focusing on a single coral species (Stylophora pistillata). It is implied that the integration of equity capitals and other commodification with reef-restoration practices will improve total reef services. Two tiers of market-related activities are defined, the traditional first-tier instruments (valuating costs/gains for extracting tradable goods and services) and novel second-tier instruments (new/expanded monetary tools developed as by-products of reef restoration measures). The emerging new suite of economic mechanisms based on restoration methodologies could be served as an incentive for ecosystem conservation, enhancing the sum values of all services generated by coral reefs, where the same stocks of farmed/transplanted coral colonies will be used as market instruments. I found that active restoration measures disclose 12 classes of second-tier goods and services, which may partly/wholly finance restoration acts, bringing to light reef capitalizations that allow the expansion of markets with products that have not been considered before. The degree to which the second tier of market-related services could buffer coral-reef degradation is still unclear and would vary with different reef types and in various reef restoration scenarios; however, reducing the uncertainty associated with restoration. It is expected that the expansion of markets with the new products and the enhancement of those already existing will be materialized even if reef ecosystems will recover into different statuses. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Quaternary fault in Hwalseong-ri, Oedong-up, Gyeongju, Korea.

    Energy Technology Data Exchange (ETDEWEB)

    Ryoo, Chung-Ryul; Chwae, Uee-Chan; Choi, Sung-Ja [Korea Institute of Geoscience and Mineral Resources, Taejeon(Korea); Son, Moon [Pusan National University, Pusan(Korea)

    2001-09-01

    We describe a Quaternary fault occurring in Hwalseong-ri, Oedong-up, Gyeongju in the eastern part of Ulsan Fault Zone, Korea. This fault (Hwalseongri Fault) is developed around the contact between the early Tertiary granite and the Quaternary gravel layer. Four different faults are distinguished from west to east: (1) fault within Quaternary gravel layer, (2) fault between Quaternary gravel layer and granite, (3) fault between Quaternary gravel layer overlying granite and granite, (4) fault between granite and Quaternary layer. General strike of the fault zone vary from NNW to NE, dipping to east. Two striations, E-W and N-S, are developed. The former is related mainly to the reverse faulting, and the latter to the sinistral shearing. This fault zone was reactivated, and considered as a positive flower structure mainly by the results of the E-W compression in the southeastern part of the Korean Peninsula during Quaternary. (author). 45 refs., 6 figs.

  2. Characterization of Quaternary and suspected Quaternary faults, regional studies, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.E.; Bucknam, R.C.; Crone, A.J.; Haller, K.M.; Machette, M.N.; Personius, S.F.; Barnhard, T.P.; Cecil, M.J.; Dart, R.L.

    1995-12-31

    This report presents the results of geologic studies that help define the Quaternary history of selected faults in the region around Yucca Mountain, Nevada. These results are relevant to the seismic-design basis of a potential nuclear waste repository at Yucca Mountain. The relevancy is based, in part, on a need for additional geologic data that became apparent in ongoing studies that resulted in the identification of 51 relevant and potentially relevant individual and compound faults and fault zones in the 100-km-radius region around the Yucca Mountain site. Geologic data used to characterize the regional faults and fault zones as relevant or potentially relevant seismic sources includes age and displacement information, maximum fault lengths, and minimum distances between the fault and the Yucca Mountain site. For many of the regional faults, no paleoseismic field studies have previously been conducted, and age and displacement data are sparse to nonexistent. In November 1994, the Branch of Earthquake and Landslide Hazards entered into two Memoranda of Agreement with the Yucca Mountain Project Branch to conduct field reconnaissance, analysis, and interpretation of six relevant and six potentially relevant regional faults. This report describes the results of study of those faults exclusive of those in the Pahrump-Stewart Valley-Ash Meadows-Amargosa Valley areas. We also include results of a cursory study of faults on the west flank of the Specter Range and in the northern part of the Last Chance Range. A four-phase strategy was implemented for the field study.

  3. A Review of SCUBA Diving Impacts and Implication for Coral Reefs Conservation and Tourism Management

    Directory of Open Access Journals (Sweden)

    Zainal Abidin Siti Zulaiha

    2014-01-01

    Full Text Available Dive tourism has become important in term of magnitude and significantly contributes to regional economies. Nevertheless, in the absence of proper controls and enforcement, unplanned tourism growth has caused environmental degradation which undermines the long-term sustainability of the tourism industry. The purpose of this paper is to explore factors that contribute to the SCUBA diving impacts on coral and fish communities. This paper explains the causes of a certain event, validating the problem of impacts, defining the core issues and identifies possible causes leading to an effect. The phenomenon of diving impacts on coral reefs is a result of intensive use of dive site over the long-term. The divers can reduce their impacts towards coral reefs through responsible diving behaviors. The causes of cumulative diver’s contacts are more complicated than it seems. In response, this paper proposes the best mitigation strategies that need to be considered for future dive tourism management.

  4. Population structure, spatial distribution and life-history traits of blacktip reef sharks Carcharhinus melanopterus.

    Science.gov (United States)

    Mourier, J; Mills, S C; Planes, S

    2013-03-01

    During a survey of the population of blacktip reef shark Carcharhinus melanopterus in Moorea (French Polynesia) between 2007 and 2011, population structural characteristics were estimated from 268 individuals. Total length (LT ) ranged from 48 to 139 cm and 48 to 157 cm for males and females, respectively, demonstrating that the average LT of females was larger than that of males. The C. melanopterus population at Moorea showed an apparent spatial sexual segregation with females preferentially frequenting lagoons and males the fore-reefs. Mean growth rate was c. 6 cm year(-1) . Males reached sexual maturity at 111 cm LT . This study reports on the population characteristics of this widespread carcharhinid shark species and makes comparisons with other locations, confirming high geographic variability in the population structure of the species. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

  5. Ontogenetic dietary changes of coral reef fishes in the mangrove-seagress-reef continuum: stable isotope and gut-content analysis

    NARCIS (Netherlands)

    Cocheret de la Morinière, E.; Pollux, B.J.A.; Nagelkerken, I.; Hemminga, M.A.; Huiskes, A.H.L.; Van der Velde, G.

    2003-01-01

    Juveniles of a number of reef fish species develop in shallow-water 'nursery' habitats such as mangroves and seagrass beds, and then migrate to the coral reef. This implies that some reef fish species are distributed over the mangrove-seagrass-reef continuum in subpopulations with different size

  6. On the long-lasting sequences of coral reef terraces from SE Sulawesi (Indonesia): Distribution, formation, and global significance

    Science.gov (United States)

    Pedoja, Kevin; Husson, Laurent; Bezos, Antoine; Pastier, Anne-Morwenn; Imran, Andy Muhammad; Arias-Ruiz, Camilo; Sarr, Anta-Clarisse; Elliot, Mary; Pons-Branchu, Edwige; Nexer, Maëlle; Regard, Vincent; Hafidz, Abdul; Robert, Xavier; Benoit, Laurent; Delcaillau, Bernard; Authemayou, Christine; Dumoulin, Caroline; Choblet, Gaël

    2018-05-01

    Many islands of the eastern Indonesian Archipelago exhibit Late Cenozoic sequences of coral reef terraces. In SE Sulawesi, on the Tukang Besi and Buton archipelagos, we identified 23 islands bearing such sequences. Remote sensing imagery and field mapping combined to U/Th and 14C dating enable to establish a chronologic framework of the reef terrace sequences from Wangi-Wangi, Buton as well as on the neighbouring, smaller islands of Ular, Siumpu and Kadatua. We identified the terraces from the last interglacial maximum (MIS 5e) at elevations lower than 20 m except on W Kadatua where it is raised at 34 ± 5 m. Such elevations yield low to moderate Upper Pleistocene uplift rates (<0.3 mm yr-1). On SE Buton Island, a sequence culminates at 650 m and includes at least 40 undated strandlines. Next to this exceptional sequence, on the Sampolawa Peninsula, 18 strandlines culminate at 430 m. Dated samples at the base of this sequence (<40 m) yield mean Middle Pleistocene uplift rates of 0.14 ± 0.09 mm yr-1. Extrapolation of these uplift rates compared to the geological setting suggests that the sequences of the Sampolawa Peninsula provide a record of sea-level high-stands for the last 3.8 ± 0.6 Ma. The sequences on SE Buton Island therefore constitute the best preserved long-lasting geomorphic record of Plio-Quaternary sea-level stands worldwide.

  7. Embracing a world of subtlety and nuance on coral reefs

    Science.gov (United States)

    Mumby, Peter J.

    2017-09-01

    Climate change will homogenise the environment and generate a preponderance of mediocre reefs. Managing seascapes of mediocrity will be challenging because our science is ill prepared to deal with the `shades of grey' of reef health; we tend to study natural processes in the healthiest reefs available. Yet much can be gained by examining the drivers and implications of even subtle changes in reef state. Where strong ecological interactions are discovered, even small changes in abundance can have profound impacts on coral resilience. Indeed, if we are to develop effective early warnings of critical losses of resilience, then monitoring must place greater emphasis on measuring and interpreting changes in reef recovery rates. In terms of mechanism, a more nuanced approach is needed to explore the generality of what might be considered `dogma'. A more nuanced approach to science will serve managers needs well and help minimise the rise of mediocrity in coral reef ecosystems.

  8. Coral Reef Resilience, Tipping Points and the Strength of Herbivory.

    Science.gov (United States)

    Holbrook, Sally J; Schmitt, Russell J; Adam, Thomas C; Brooks, Andrew J

    2016-11-02

    Coral reefs increasingly are undergoing transitions from coral to macroalgal dominance. Although the functional roles of reef herbivores in controlling algae are becoming better understood, identifying possible tipping points in the herbivory-macroalgae relationships has remained a challenge. Assessment of where any coral reef ecosystem lies in relation to the coral-to-macroalgae tipping point is fundamental to understanding resilience properties, forecasting state shifts, and developing effective management practices. We conducted a multi-year field experiment in Moorea, French Polynesia to estimate these properties. While we found a sharp herbivory threshold where macroalgae escape control, ambient levels of herbivory by reef fishes were well above that needed to prevent proliferation of macroalgae. These findings are consistent with previously observed high resilience of the fore reef in Moorea. Our approach can identify vulnerable coral reef systems in urgent need of management action to both forestall shifts to macroalgae and preserve properties essential for resilience.

  9. Phytoplankton phenology indices in coral reef ecosystems: Application to ocean-color observations in the Red Sea

    KAUST Repository

    Racault, Marie-Fanny

    2015-02-18

    Phytoplankton, at the base of the marine food web, represent a fundamental food source in coral reef ecosystems. The timing (phenology) and magnitude of the phytoplankton biomass are major determinants of trophic interactions. The Red Sea is one of the warmest and most saline basins in the world, characterized by an arid tropical climate regulated by the monsoon. These extreme conditions are particularly challenging for marine life. Phytoplankton phenological indices provide objective and quantitative metrics to characterize phytoplankton seasonality. The indices i.e. timings of initiation, peak, termination and duration are estimated here using 15 years (1997–2012) of remote sensing ocean-color data from the European Space Agency (ESA) Climate Change Initiative project (OC-CCI) in the entire Red Sea basin. The OC-CCI product, comprising merged and bias-corrected observations from three independent ocean-color sensors (SeaWiFS, MODIS and MERIS), and processed using the POLYMER algorithm (MERIS period), shows a significant increase in chlorophyll data coverage, especially in the southern Red Sea during the months of summer NW monsoon. In open and reef-bound coastal waters, the performance of OC-CCI chlorophyll data is shown to be comparable with the performance of other standard chlorophyll products for the global oceans. These features have permitted us to investigate phytoplankton phenology in the entire Red Sea basin, and during both winter SE monsoon and summer NW monsoon periods. The phenological indices are estimated in the four open water provinces of the basin, and further examined at six coral reef complexes of particular socio-economic importance in the Red Sea, including Siyal Islands, Sharm El Sheikh, Al Wajh bank, Thuwal reefs, Al Lith reefs and Farasan Islands. Most of the open and deeper waters of the basin show an apparent higher chlorophyll concentration and longer duration of phytoplankton growth during the winter period (relative to the summer

  10. Notes on common macrobenthic reef invertebrates of Tubbataha Reefs Natural Park, Philippines

    Directory of Open Access Journals (Sweden)

    Jean Beth S. Jontila

    2012-12-01

    Full Text Available Macrobenthic reef invertebrates are important reef health indicators and fishery resources but are not very well documented in Tubbataha Reefs Natural Park. To provide notes on the species composition and the abundance and size of commonly encountered macrobenthic reef invertebrates, belt transects survey in intertidal, shallow, and deep subtidal reef habitats were conducted. In total, 18 species were recorded, six of which were echinoderms and 12 were mollusks, which include the rare giant clam Hippopusporcellanus. Only the giant clam Tridacna crocea and the top shell Trochus niloticus occurred in all seven permanent monitoring sites but the two species varied in densities across depths. There was also an outbreak of crown-of-thorns (COTs sea stars in some sites. The large variation in the density of each species across sites and depths suggests niche differences, overharvesting, or their recovery fromhaving been overly exploited. Separate monitoring areas for each commercially important species are suggested to determine how their populations respond to poaching and their implications on the park’s long term management.

  11. Social interactions among grazing reef fish drive material flux in a coral reef ecosystem.

    Science.gov (United States)

    Gil, Michael A; Hein, Andrew M

    2017-05-02

    In human financial and social systems, exchanges of information among individuals cause speculative bubbles, behavioral cascades, and other correlated actions that profoundly influence system-level function. Exchanges of information are also widespread in ecological systems, but their effects on ecosystem-level processes are largely unknown. Herbivory is a critical ecological process in coral reefs, where diverse assemblages of fish maintain reef health by controlling the abundance of algae. Here, we show that social interactions have a major effect on fish grazing rates in a reef ecosystem. We combined a system for observing and manipulating large foraging areas in a coral reef with a class of dynamical decision-making models to reveal that reef fish use information about the density and actions of nearby fish to decide when to feed on algae and when to flee foraging areas. This "behavioral coupling" causes bursts of feeding activity that account for up to 68% of the fish community's consumption of algae. Moreover, correlations in fish behavior induce a feedback, whereby each fish spends less time feeding when fewer fish are present, suggesting that reducing fish stocks may not only reduce total algal consumption but could decrease the amount of algae each remaining fish consumes. Our results demonstrate that social interactions among consumers can have a dominant effect on the flux of energy and materials through ecosystems, and our methodology paves the way for rigorous in situ measurements of the behavioral rules that underlie ecological rates in other natural systems.

  12. The unnatural history of Kāne‘ohe Bay: coral reef resilience in the face of centuries of anthropogenic impacts

    Directory of Open Access Journals (Sweden)

    Keisha D. Bahr

    2015-05-01

    Full Text Available Kāneʻohe Bay, which is located on the on the NE coast of Oʻahu, Hawaiʻi, represents one of the most intensively studied estuarine coral reef ecosystems in the world. Despite a long history of anthropogenic disturbance, from early settlement to post European contact, the coral reef ecosystem of Kāneʻohe Bay appears to be in better condition in comparison to other reefs around the world. The island of Moku o Loʻe (Coconut Island in the southern region of the bay became home to the Hawaiʻi Institute of Marine Biology in 1947, where researchers have since documented the various aspects of the unique physical, chemical, and biological features of this coral reef ecosystem. The first human contact by voyaging Polynesians occurred at least 700 years ago. By A.D. 1250 Polynesians voyagers had settled inhabitable islands in the region which led to development of an intensive agricultural, fish pond and ocean resource system that supported a large human population. Anthropogenic disturbance initially involved clearing of land for agriculture, intentional or accidental introduction of alien species, modification of streams to supply water for taro culture, and construction of massive shoreline fish pond enclosures and extensive terraces in the valleys that were used for taro culture. The arrival by the first Europeans in 1778 led to further introductions of plants and animals that radically changed the landscape. Subsequent development of a plantation agricultural system led to increased human immigration, population growth and an end to traditional land and water management practices. The reefs were devastated by extensive dredge and fill operations as well as rapid growth of human population, which led to extensive urbanization of the watershed. By the 1960’s the bay was severely impacted by increased sewage discharge along with increased sedimentation due to improper grading practices and stream channelization, resulting in extensive loss of

  13. The unnatural history of Kāne'ohe Bay: coral reef resilience in the face of centuries of anthropogenic impacts.

    Science.gov (United States)

    Bahr, Keisha D; Jokiel, Paul L; Toonen, Robert J

    2015-01-01

    Kāne'ohe Bay, which is located on the on the NE coast of O'ahu, Hawai'i, represents one of the most intensively studied estuarine coral reef ecosystems in the world. Despite a long history of anthropogenic disturbance, from early settlement to post European contact, the coral reef ecosystem of Kāne'ohe Bay appears to be in better condition in comparison to other reefs around the world. The island of Moku o Lo'e (Coconut Island) in the southern region of the bay became home to the Hawai'i Institute of Marine Biology in 1947, where researchers have since documented the various aspects of the unique physical, chemical, and biological features of this coral reef ecosystem. The first human contact by voyaging Polynesians occurred at least 700 years ago. By A.D. 1250 Polynesians voyagers had settled inhabitable islands in the region which led to development of an intensive agricultural, fish pond and ocean resource system that supported a large human population. Anthropogenic disturbance initially involved clearing of land for agriculture, intentional or accidental introduction of alien species, modification of streams to supply water for taro culture, and construction of massive shoreline fish pond enclosures and extensive terraces in the valleys that were used for taro culture. The arrival by the first Europeans in 1778 led to further introductions of plants and animals that radically changed the landscape. Subsequent development of a plantation agricultural system led to increased human immigration, population growth and an end to traditional land and water management practices. The reefs were devastated by extensive dredge and fill operations as well as rapid growth of human population, which led to extensive urbanization of the watershed. By the 1960's the bay was severely impacted by increased sewage discharge along with increased sedimentation due to improper grading practices and stream channelization, resulting in extensive loss of coral cover. The reefs of K

  14. Effects of High Dissolved Inorganic and Organic Carbon Availability on the Physiology of the Hard Coral Acropora millepora from the Great Barrier Reef.

    Directory of Open Access Journals (Sweden)

    Friedrich W Meyer

    Full Text Available Coral reefs are facing major global and local threats due to climate change-induced increases in dissolved inorganic carbon (DIC and because of land-derived increases in organic and inorganic nutrients. Recent research revealed that high availability of labile dissolved organic carbon (DOC negatively affects scleractinian corals. Studies on the interplay of these factors, however, are lacking, but urgently needed to understand coral reef functioning under present and near future conditions. This experimental study investigated the individual and combined effects of ambient and high DIC (pCO2 403 μatm/ pHTotal 8.2 and 996 μatm/pHTotal 7.8 and DOC (added as Glucose 0 and 294 μmol L-1, background DOC concentration of 83 μmol L-1 availability on the physiology (net and gross photosynthesis, respiration, dark and light calcification, and growth of the scleractinian coral Acropora millepora (Ehrenberg, 1834 from the Great Barrier Reef over a 16 day interval. High DIC availability did not affect photosynthesis, respiration and light calcification, but significantly reduced dark calcification and growth by 50 and 23%, respectively. High DOC availability reduced net and gross photosynthesis by 51% and 39%, respectively, but did not affect respiration. DOC addition did not influence calcification, but significantly increased growth by 42%. Combination of high DIC and high DOC availability did not affect photosynthesis, light calcification, respiration or growth, but significantly decreased dark calcification when compared to both controls and DIC treatments. On the ecosystem level, high DIC concentrations may lead to reduced accretion and growth of reefs dominated by Acropora that under elevated DOC concentrations will likely exhibit reduced primary production rates, ultimately leading to loss of hard substrate and reef erosion. It is therefore important to consider the potential impacts of elevated DOC and DIC simultaneously to assess real world

  15. Coral reefs as indicators of marine environmental health

    International Nuclear Information System (INIS)

    Kumaraguru, A.K.

    2007-01-01

    Coral reefs are one of the most productive and diverse of all ecosystems on the Earth. Although they occupy less than 0.25 percent of the marine environment, the reefs support more than a quarter of all known fish species. They serve as critical habitats for numerous tropical species including reef fishes of ornamental nature and edible fishes. They protect the shores from storms and wave actions

  16. Vaal Reefs: 1700 t/a uranium by 1982

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    South Africa's 16th uranium plant - the South Plant of Anglo American's Vaal Reefs mine in the Western Transvaal - has been officially opened by Dr A.J.A. Roux. Vaal Reefs is South Africa's principal producer of uranium, and responsible for a quarter of the output - a proportion which will increase with the new South Plant coming fully on stream. Vaal Reefs is also the largest gold mining operation in the world

  17. The Decline of Coral Reefs: a Political Economy Approach

    OpenAIRE

    Samuel, Asumadu-Sarkodie

    2015-01-01

    Coral reefs provide economic services like job, food and tourism. Yet, within the past decades, there has been an overwhelming decline in the vitality of coral reefs and their ecosystem. Scientist have not be able to set the record straight regarding their scientific argument on biodiversity and ecological wealth of natural environment. Therefore, actions to recover coral reefs from destruction have proved futile. This paper will analyze the economical values, economic valuation, socioeconomi...

  18. Modeling Reef Island Morphodynamics in Profile and Plan View

    Science.gov (United States)

    Ashton, A. D.; Ortiz, A. C.; Lorenzo-Trueba, J.

    2016-12-01

    Reef islands are carbonate detrital landforms perched atop shallow reef flats of atolls and barrier reef systems. Often comprising the only subaerial, inhabitable land of many island chains and island nations, these low-lying, geomorphically active landforms face considerable hazards from climate change. While there hazards include wave overtopping and groundwater salinization, sea-level rise and wave climate change will affect sediment transport and shoreline dynamics, including the possibility for wholesale reorganization of the islands themselves. Here we present a simplified morphodynamic model that can spatially quantify the potential impacts of climate change on reef islands. Using parameterizations of sediment transport pathways and feedbacks from previously presented XBeach modeling results, we investigate how sea-level rise, change in storminess, and different carbonate production rates can affect the profile evolution of reef islands, including feedbacks with the shallow reef flat that bounds the islands offshore (and lagoonward). Model results demonstrate that during rising sea levels, the reef flat can serve as a sediment trap, starving reef islands of detrital sediment that could otherwise fortify the shore against sea-level-rise-driven erosion. On the other hand, if reef flats are currently shallow (likely due to geologic inheritance or biologic cementation processes) such that sea-level rise does not result in sediment accumulation on the flat, reef island shorelines may be more resilient to rising seas. We extend the model in plan view to examine how long-term (decadal) changes in wave approach direction could affect reef island shoreline orientation. We compare model results to historical and geologic change for different case studies on the Marshall Islands. This simplified modeling approach, focusing on boundary dynamics and mass fluxes, provides a quantitative tool to predict the response of reef island environments to climate change.

  19. Historic impact of watershed change and sedimentation to reefs along west-central Guam

    Science.gov (United States)

    Prouty, Nancy G.; Storlazzi, Curt D.; McCutcheon, Amanda L.; Jenson, John W.

    2014-01-01

    Using coral growth parameters (extension, density, calcification rates, and luminescence) and geochemical measurements (barium to calcium rations; Ba/Ca) from coral cores collected in west-central Guam, we provide a historic perspective on sediment input to coral reefs adjacent to the Piti-Asan watershed. The months of August through December are dominated by increased coral Ba/Ca values, corresponding to the rainy season. With river water enriched in barium related to nearshore seawater, coral Ba/Ca ratios are presented as a proxy for input of fine-grained terrigenous sediment to the nearshore environment. The century-long Ba/Ca coral record indicates that the Asan fore reef is within the zone of impact from discharged sediments transported from the Piti-Asan watershed and has experienced increased terrestrial sedimentation since the 1940s. This abrupt shift in sedimentation occurred at the same time as both the sudden denudation of the landscape by military ordinance and the immediate subsequent development of the Asan area through the end of the war, from 1944 through 1945. In response to rapid input of sediment, as determined from coral Ba/Ca values, coral growth rates were reduced for almost two decades, while calcification rates recovered much more quickly. Furthermore, coral luminescence is decoupled from the Ba/Ca record, which is consistent with degradation of soil organic matter through disturbance by forest fires, suggesting a potential index of fire history and degradation of soil organic matter. These patterns were not seen in the cores from nearby reefs associated with watersheds that have not undergone the same degree of landscape denudation. Taken together, these records provide a valuable tool for understanding the compounding effects of land-use change on coral reef health.

  20. Historic impact of watershed change and sedimentation to reefs along west-central Guam

    Science.gov (United States)

    Prouty, Nancy G.; Storlazzi, Curt D.; McCutcheon, Amanda L.; Jenson, John W.

    2014-09-01

    Using coral growth parameters (extension, density, calcification rates, and luminescence) and geochemical measurements (barium to calcium rations; Ba/Ca) from coral cores collected in west-central Guam, we provide a historic perspective on sediment input to coral reefs adjacent to the Piti-Asan watershed. The months of August through December are dominated by increased coral Ba/Ca values, corresponding to the rainy season. With river water enriched in barium related to nearshore seawater, coral Ba/Ca ratios are presented as a proxy for input of fine-grained terrigenous sediment to the nearshore environment. The century-long Ba/Ca coral record indicates that the Asan fore reef is within the zone of impact from discharged sediments transported from the Piti-Asan watershed and has experienced increased terrestrial sedimentation since the 1940s. This abrupt shift in sedimentation occurred at the same time as both the sudden denudation of the landscape by military ordinance and the immediate subsequent development of the Asan area through the end of the war, from 1944 through 1945. In response to rapid input of sediment, as determined from coral Ba/Ca values, coral growth rates were reduced for almost two decades, while calcification rates recovered much more quickly. Furthermore, coral luminescence is decoupled from the Ba/Ca record, which is consistent with degradation of soil organic matter through disturbance by forest fires, suggesting a potential index of fire history and degradation of soil organic matter. These patterns were not seen in the cores from nearby reefs associated with watersheds that have not undergone the same degree of landscape denudation. Taken together, these records provide a valuable tool for understanding the compounding effects of land-use change on coral reef health.

  1. A unified framework for modelling sediment fate from source to sink and its interactions with reef systems over geological times.

    Science.gov (United States)

    Salles, Tristan; Ding, Xuesong; Webster, Jody M; Vila-Concejo, Ana; Brocard, Gilles; Pall, Jodie

    2018-03-27

    Understanding the effects of climatic variability on sediment dynamics is hindered by limited ability of current models to simulate long-term evolution of sediment transfer from source to sink and associated morphological changes. We present a new approach based on a reduced-complexity model which computes over geological time: sediment transport from landmasses to coasts, reworking of marine sediments by longshore currents, and development of coral reef systems. Our framework links together the main sedimentary processes driving mixed siliciclastic-carbonate system dynamics. It offers a methodology for objective and quantitative sediment fate estimations over regional and millennial time-scales. A simulation of the Holocene evolution of the Great Barrier Reef shows: (1) how high sediment loads from catchments erosion prevented coral growth during the early transgression phase and favoured sediment gravity-flows in the deepest parts of the northern region basin floor (prior to 8 ka before present (BP)); (2) how the fine balance between climate, sea-level, and margin physiography enabled coral reefs to thrive under limited shelf sedimentation rates after ~6 ka BP; and, (3) how since 3 ka BP, with the decrease of accommodation space, reduced of vertical growth led to the lateral extension of reefs consistent with available observational data.

  2. Boussinesq Modeling of Wave Propagation and Runup over Fringing Coral Reefs, Model Evaluation Report

    National Research Council Canada - National Science Library

    Demirbilek, Zeki; Nwogu, Okey G

    2007-01-01

    ..., for waves propagating over fringing reefs. The model evaluation had two goals: (a) investigate differences between laboratory and field characteristics of wave transformation processes over reefs, and (b...

  3. Occurrence and genesis of Quaternary microbialitic tufa at Hammam Al Ali, Oman

    Science.gov (United States)

    Khalaf, Fikry I.

    2017-05-01

    Remnants of late Quaternary microbialitic tufa occurs within a shallow depression in the Hammam Al Ali hot spring area, which is located approximately 14.5 km to the southwest of Muscat, Oman. The tufa precipitated from hot spring water supersaturated with respect to calcium carbonate and is mostly of a porous phytogenic type, with occasional detrital and stromatolitic types. Microscopic and nanoscopic examination revealed that the tufa deposits developed through two successive processes of calcite precipitation, biotic and abiotic, preceded by limited precipitation of unstable aragonite. It is suggested that biologically mediated precipitation results in the construction of incomplete skeletal calcite crystals. The latter provide a base for classical physiochemical precipitation and, eventually, the development of complete sparry calcite crystals. The initiation of dendritic calcite crystals in the stromatolitic tufa as incomplete biogenic skeletal crystals and their characteristic growth pattern indicates that the tufa represents a clear example of hot spring calcitic microbialite.

  4. Carbon budget of coral reef systems: an overview of observations in fringing reefs, barrier reefs and atolls in the Indo-Pacific regions

    International Nuclear Information System (INIS)

    Suzuki, Atsushi; Kawahata, Hodaka

    2003-01-01

    The seawater CO 2 system and carbon budget were examined in coral reefs of wide variety with respect to topographic types and oceanographic settings in the Indo-Pacific oceans. A system-level net organic-to-inorganic carbon production ratio (ROI) is a master parameter for controlling the carbon cycle in coral reef systems, including their sink/source behavior for atmospheric CO 2 . A reef system with ROI less than approximately 0.6 has a potential for releasing CO 2 . The production ratio, however, is not easy to estimate on a particular reef. Instead, observations planned to detect the offshore-lagoon difference in partial pressure of CO 2 (pCO 2 ) and a graphic approach based on a total alkalinity-dissolved inorganic carbon diagram can reveal system-level performance of the carbon cycle in coral reefs. Surface pCO 2 values in the lagoons of atolls and barrier reefs were consistently higher than those in their offshore waters, showing differences between 6 and 46 atm, together with a depletion in total alkalinity up to 100 mol/kg, indicating predominant carbonate production relative to net organic carbon production. Reef topography, especially residence time of lagoon water, has a secondary effect on the magnitude of the offshore-lagoon pCO 2 difference. Terrestrial influence was recognized in coastal reefs, including the GBR lagoon and a fringing reef of the Ryukyu Islands. High carbon input appears to enhance CO 2 efflux to the atmosphere because of their high dissolved C:P ratios. Coral reefs, in general, act as an alkalinity sink and a potentially CO 2 -releasing site due to carbonate precipitation and land-derived carbon

  5. Carbon budget of coral reef systems: an overview of observations in fringing reefs, barrier reefs and atolls in the Indo-Pacific regions

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Atsushi; Kawahata, Hodaka [National Inst. of Advanced Industrial Science and Technology, Ibaraki (Japan). Inst. for Marine Resources and Environment

    2003-04-01

    The seawater CO{sub 2} system and carbon budget were examined in coral reefs of wide variety with respect to topographic types and oceanographic settings in the Indo-Pacific oceans. A system-level net organic-to-inorganic carbon production ratio (ROI) is a master parameter for controlling the carbon cycle in coral reef systems, including their sink/source behavior for atmospheric CO{sub 2}. A reef system with ROI less than approximately 0.6 has a potential for releasing CO{sub 2}. The production ratio, however, is not easy to estimate on a particular reef. Instead, observations planned to detect the offshore-lagoon difference in partial pressure of CO{sub 2} (pCO{sub 2}) and a graphic approach based on a total alkalinity-dissolved inorganic carbon diagram can reveal system-level performance of the carbon cycle in coral reefs. Surface pCO{sub 2} values in the lagoons of atolls and barrier reefs were consistently higher than those in their offshore waters, showing differences between 6 and 46 atm, together with a depletion in total alkalinity up to 100 mol/kg, indicating predominant carbonate production relative to net organic carbon production. Reef topography, especially residence time of lagoon water, has a secondary effect on the magnitude of the offshore-lagoon pCO{sub 2} difference. Terrestrial influence was recognized in coastal reefs, including the GBR lagoon and a fringing reef of the Ryukyu Islands. High carbon input appears to enhance CO{sub 2} efflux to the atmosphere because of their high dissolved C:P ratios. Coral reefs, in general, act as an alkalinity sink and a potentially CO{sub 2}-releasing site due to carbonate precipitation and land-derived carbon.

  6. Cryptic Coral Reef Diversity Across the Pacific Assessed using Autonomous Reef Monitoring Structures and Multi-omic Methods

    Science.gov (United States)

    Ransome, E. J.; Timmers, M.; Hartmann, A.; Collins, A.; Meyer, C.

    2016-02-01

    Coral reefs harbor diverse and distinct eukaryotic, bacterial and viral communities, which are critically important for their success. The lack of standardized measures for comprehensively assessing reef diversity has been a major obstacle in understanding the complexity of eukaryotic and microbial associations, and the processes that drive ecosystem shifts on reefs. ARMS, which mimic the structural complexity of the reef using artificial settlement plates, were used to systematically measure reef biodiversity across the Indo-Pacific. This device allows for standardized sampling of reef microbes to metazoans, providing the opportunity to investigate the fundamental links between these groups at an ecosystem level. We integrate the use of traditional ecology methods with metagenomics and metabolomics (metabolic predictors) to quantify the taxonomic composition of one of the planet's most diverse ecosystems and to assess the fundamental links between these cryptic communities and ecosystem function along geographical and anthropogenic stress gradients.

  7. Functionally diverse reef-fish communities ameliorate coral disease.

    Science.gov (United States)

    Raymundo, Laurie J; Halford, Andrew R; Maypa, Aileen P; Kerr, Alexander M

    2009-10-06

    Coral reefs, the most diverse of marine ecosystems, currently experience unprecedented levels of degradation. Diseases are now recognized as a major cause of mortality in reef-forming corals and are complicit in phase shifts of reef ecosystems to algal-dominated states worldwide. Even so, factors contributing to disease occurrence, spread, and impact remain poorly understood. Ecosystem resilience has been linked to the conservation of functional diversity, whereas overfishing reduces functional diversity through cascading, top-down effects. Hence, we tested the hypothesis that reefs with trophically diverse reef fish communities have less coral disease than overfished reefs. We surveyed reefs across the central Philippines, including well-managed marine protected areas (MPAs), and found that disease prevalence was significantly negatively correlated with fish taxonomic diversity. Further, MPAs had significantly higher fish diversity and less disease than unprotected areas. We subsequently investigated potential links between coral disease and the trophic components of fish diversity, finding that only the density of coral-feeding chaetodontid butterflyfishes, seldom targeted by fishers, was positively associated with disease prevalence. These previously uncharacterized results are supported by a second large-scale dataset from the Great Barrier Reef. We hypothesize that members of the charismatic reef-fish family Chaetodontidae are major vectors of coral disease by virtue of their trophic specialization on hard corals and their ecological release in overfished areas, particularly outside MPAs.

  8. Coral reef connectivity within the Western Gulf of Mexico

    Science.gov (United States)

    Salas-Monreal, David; Marin-Hernandez, Mark; Salas-Perez, Jose de Jesus; Salas-de-Leon, David Alberto; Monreal-Gomez, Maria Adela; Perez-España, Horacio

    2018-03-01

    The yearlong monthly mean satellite data of the geostrophic velocities, the sea surface temperature and the chlorophyll-a values were used to elucidate any possible pathway among the different coral reef systems of the Western Gulf of Mexico (WGM). The geostrophic current velocities suggested different pathways connecting the coral reef areas. The typical coastal alongshore pathway constricted to the continental shelf, and two open ocean pathway, the first connecting the Campeche Reef System (CRS) with the Veracruz (VRS) and Tuxpan-Lobos Reef Systems (TLRS), and the second pathway connecting the Tuxpan-Lobos Reef System with the Flower Garden Reef System (FGRS). According to the pathways there should be more larvae transport from the southern Gulf of Mexico reef systems toward the FGRS than the other way. The connection from the southern Gulf of Mexico toward the FGRS took place during January, May, July, August and September (2015), while the connection from the FGRS toward the southern Gulf of Mexico reef system took place during January and February (2015), this was also suggested via model outputs. The density radio (R) was used as a first approximation to elucidate the influence of the freshwater continental discharges within the continental shelf. All coral reef areas were located where the Chlorophyll-a monthly mean values had values bellow 1 mg m- 2 with a density radio between 0 and 1, i.e. under the influence of continental discharges.

  9. Using virtual reality to estimate aesthetic values of coral reefs

    Science.gov (United States)

    Clifford, Sam; Caley, M. Julian; Pearse, Alan R.; Brown, Ross; James, Allan; Christensen, Bryce; Bednarz, Tomasz; Anthony, Ken; González-Rivero, Manuel; Mengersen, Kerrie; Peterson, Erin E.

    2018-01-01

    Aesthetic value, or beauty, is important to the relationship between humans and natural environments and is, therefore, a fundamental socio-economic attribute of conservation alongside other ecosystem services. However, beauty is difficult to quantify and is not estimated well using traditional approaches to monitoring coral-reef aesthetics. To improve the estimation of ecosystem aesthetic values, we developed and implemented a novel framework used to quantify features of coral-reef aesthetics based on people's perceptions of beauty. Three observer groups with different experience to reef environments (Marine Scientist, Experienced Diver and Citizen) were virtually immersed in Australian's Great Barrier Reef (GBR) using 360° images. Perceptions of beauty and observations were used to assess the importance of eight potential attributes of reef-aesthetic value. Among these, heterogeneity, defined by structural complexity and colour diversity, was positively associated with coral-reef-aesthetic values. There were no group-level differences in the way the observer groups perceived reef aesthetics suggesting that past experiences with coral reefs do not necessarily influence the perception of beauty by the observer. The framework developed here provides a generic tool to help identify indicators of aesthetic value applicable to a wide variety of natural systems. The ability to estimate aesthetic values robustly adds an important dimension to the holistic conservation of the GBR, coral reefs worldwide and other natural ecosystems. PMID:29765676

  10. Relationships between structural complexity, coral traits, and reef fish assemblages

    Science.gov (United States)

    Darling, Emily S.; Graham, Nicholas A. J.; Januchowski-Hartley, Fraser A.; Nash, Kirsty L.; Pratchett, Morgan S.; Wilson, Shaun K.

    2017-06-01

    With the ongoing loss of coral cover and the associated flattening of reef architecture, understanding the links between coral habitat and reef fishes is of critical importance. Here, we investigate whether considering coral traits and functional diversity provides new insights into the relationship between structural complexity and reef fish communities, and whether coral traits and community composition can predict structural complexity. Across 157 sites in Seychelles, Maldives, the Chagos Archipelago, and Australia's Great Barrier Reef, we find that structural complexity and reef zone are the strongest and most consistent predictors of reef fish abundance, biomass, species richness, and trophic structure. However, coral traits, diversity, and life histories provided additional predictive power for models of reef fish assemblages, and were key drivers of structural complexity. Our findings highlight that reef complexity relies on living corals—with different traits and life histories—continuing to build carbonate skeletons, and that these nuanced relationships between coral assemblages and habitat complexity can affect the structure of reef fish assemblages. Seascape-level estimates of structural complexity are rapid and cost effective with important implications for the structure and function of fish assemblages, and should be incorporated into monitoring programs.

  11. Behavioral Ecology of Coral Reef Fishes at Spawning Aggregation Sites

    National Research Council Canada - National Science Library

    Sancho, Gorka

    1998-01-01

    This thesis is an extensive investigation of the behavioral and ecological relationships between spawning reef fishes, their predators, and various environmental parameters at spawning aggregation sites...

  12. Overview on artificial reefs in Europe

    Directory of Open Access Journals (Sweden)

    Gianna Fabi

    2011-01-01

    Full Text Available Artificial reefs in Europe have been developed over the last 40 yrs. Most of these reefs have been placed in the Mediterranean Sea, but there is an increasing interest on the part of northern European countries. Fish stock enhancement and fishery management are the main purposes of reef construction in the Mediterranean Sea and on the Atlantic coast of the Iberian Peninsula, while nature conservation/restoration, research, and recreation have been the main purposes served in the other European regions to date. Artificial reef deployment falls under some general regulations concerning the protection of the sea against pollution due to the dumping of unsuitable materials. Specific Regional Plans relating to the use of artificial reefs in the marine environment and Guidelines for reef construction have been derived from these general regulations. In spite of recent developments, national and/or regional programs for the deployment of artificial reefs and/or their inclusion in overall management plans for integrated management of coastal zones are in force only in the majority of Mediterranean countries, while only a few projects have, to date, been undertaken in the other European Regions. Moreover, there is a noteworthy lack of plans, in many countries, for the management of the reefs after their deployment.Os recifes artificiais, na Europa, foram desenvolvidos nos últimos 40 anos. A maioria desses recifes foram instalados n