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Sample records for sea coral reef

  1. Wave transformation across coral reefs under changing sea levels

    NASA Astrophysics Data System (ADS)

    Harris, Daniel; Power, Hannah; Vila-Conejo, Ana; Webster, Jody

    2015-04-01

    The transformation of swell waves from deep water across reef flats is the primary process regulating energy regimes in coral reef systems. Coral reefs are effective barriers removing up to 99% of wave energy during breaking and propagation across reef flats. Consequently back-reef environments are often considered low energy with only limited sediment transport and geomorphic change during modal conditions. Coral reefs, and specifically reef flats, therefore provide important protection to tropical coastlines from coastal erosion and recession. However, changes in sea level could lead to significant changes in the dissipation of swell wave energy in coral reef systems with wave heights dependent on the depth over the reef flat. This suggests that a rise in sea level would also lead to significantly higher energy conditions exacerbating the transgressive effects of sea level rise on tropical beaches and reef islands. This study examines the potential implications of different sea level scenarios on the transformation of waves across the windward reef flats of One Tree Reef, southern Great Barrier Reef. Waves were measured on the reef flats and back-reef sand apron of One Tree Reef. A one-dimensional wave model was calibrated and used to investigate wave processes on the reef flats under different mean sea level (MSL) scenarios (present MSL, +1 m MSL, and +2 m MSL). These scenarios represent both potential future sea level states and also the paleo sea level of the late Holocene in the southern Great Barrier Reef. Wave heights were shown to increase under sea level rise, with greater wave induced orbital velocities affecting the bed under higher sea levels. In general waves were more likely to entrain and transport sediment both on the reef flat and in the back reef environment under higher sea levels which has implications for not only forecasted climate change scenarios but also for interpreting geological changes during the late Holocene when sea levels were 1

  2. History of coral reefs and sea level

    SciTech Connect

    Fairbridge, R.W.

    1985-01-01

    Charles Darwin proposed crustal subsidence for atoll growth, on the Beagle, between England and Brazil, before even seeing a coral reef, on the basis of charts and discussions with Captain Fitzroy. Relative change of sea level due to crustal movements was then well-accepted from evidence of raised strandlines in Scandinavia and Scotland and sunken forests in England. Darwin added global change of sea level (tectonoeustasy) caused by remote tectonic activity, as explained by Robert Chambers (1848, p. 319). The glacioeustasy concept was mooted soon afterwards, though the term itself came later. When Suess in 1888 proposed eustatic change, he had in mind Archimedian displacement of water by sediment or lava accumulation on the sea floor. Integrated ideas of reef development also came in the 20th century. The powerful arguments against Darwin were led by Murray with his solution hypothesis, which can not be judged as good observation but from a narrow viewpoint. The Royal Society reef borings at Funafuti were heroic but at the same time misread. Subsequently came isotopic geochemistry, absolute dating, the Milankovitch insolation theory, and plate tectonics. And much more field work. The result is an integrated reef growth theory.

  3. The ecological research on coral reefs of the Red Sea

    NASA Astrophysics Data System (ADS)

    Mergner, Hans

    Klunzinger (1872) characterised the zonation of the coral reef near Al-Qusayr, Egypt with the help of indicator species. He identified a Stylophora-zone among other zones and established the first biophysiographic zonation of a coral reef which is, in many respects, still valid today. Since then, ecological research work on coral reefs has developed to its present understanding of one of the most complicated and densely populated ecosystems on Earth. Much biological and ecological work has been done on the coral reefs along the Red Sea coasts. This is not surrising, because the Red Sea is the coral sea closest to Europe and has attracted the interest of European investigators for over 200 years. With few exceptions, this interest has been concentrated on a limited number of coastal sites: Jeddah, Al-Qunfudhah, Al-Luhayyah and Al-Mukha along the east coast, and Assab, Mesewa, Al-Qusayr and As-Suways along the west coast. Although the early coral reef workers were primarily interested in collecting animals, they also made some informal observations on the habitats of the species they collected. However, full ecological statements were rare — with the exception of those of Klunzinger (1872). Research centres have been established and active programmes continue on the Sudanese coast at Dungunab (since 1907), Sawakin and Bur Sudan (since 1963 when the first ecological investigations on Bur Sudan coral reefs occured (Mergner, 1967), and in 1974 and 1976 respectively the biological stations at Sawakin and Bur Sudan were established), on the Egyptian coast at Al-Ghardaga (since 1930), on the Sinai coast at Eilat (since 1968) and on the Jordan coast at Al-Aqabah (since 1972). New research centres continue to open, such as aong the east coast at Jeddah. The special interest of the ecology of Red Sea coral reefs is that it encompasses a broad range of problems: the influence of abiotic factors on the community structure, distribution and species diversity of corals and the

  4. A coral reef refuge in the Red Sea.

    PubMed

    Fine, Maoz; Gildor, Hezi; Genin, Amatzia

    2013-12-01

    The stability and persistence of coral reefs in the decades to come is uncertain due to global warming and repeated bleaching events that will lead to reduced resilience of these ecological and socio-economically important ecosystems. Identifying key refugia is potentially important for future conservation actions. We suggest that the Gulf of Aqaba (GoA) (Red Sea) may serve as a reef refugium due to a unique suite of environmental conditions. Our hypothesis is based on experimental detection of an exceptionally high bleaching threshold of northern Red Sea corals and on the potential dispersal of coral planulae larvae through a selective thermal barrier estimated using an ocean model. We propose that millennia of natural selection in the form of a thermal barrier at the southernmost end of the Red Sea have selected coral genotypes that are less susceptible to thermal stress in the northern Red Sea, delaying bleaching events in the GoA by at least a century.

  5. Prioritizing Land and Sea Conservation Investments to Protect Coral Reefs

    PubMed Central

    Klein, Carissa J.; Ban, Natalie C.; Halpern, Benjamin S.; Beger, Maria; Game, Edward T.; Grantham, Hedley S.; Green, Alison; Klein, Travis J.; Kininmonth, Stuart; Treml, Eric; Wilson, Kerrie; Possingham, Hugh P.

    2010-01-01

    Background Coral reefs have exceptional biodiversity, support the livelihoods of millions of people, and are threatened by multiple human activities on land (e.g. farming) and in the sea (e.g. overfishing). Most conservation efforts occur at local scales and, when effective, can increase the resilience of coral reefs to global threats such as climate change (e.g. warming water and ocean acidification). Limited resources for conservation require that we efficiently prioritize where and how to best sustain coral reef ecosystems. Methodology/Principal Findings Here we develop the first prioritization approach that can guide regional-scale conservation investments in land- and sea-based conservation actions that cost-effectively mitigate threats to coral reefs, and apply it to the Coral Triangle, an area of significant global attention and funding. Using information on threats to marine ecosystems, effectiveness of management actions at abating threats, and the management and opportunity costs of actions, we calculate the rate of return on investment in two conservation actions in sixteen ecoregions. We discover that marine conservation almost always trumps terrestrial conservation within any ecoregion, but terrestrial conservation in one ecoregion can be a better investment than marine conservation in another. We show how these results could be used to allocate a limited budget for conservation and compare them to priorities based on individual criteria. Conclusions/Significance Previous prioritization approaches do not consider both land and sea-based threats or the socioeconomic costs of conserving coral reefs. A simple and transparent approach like ours is essential to support effective coral reef conservation decisions in a large and diverse region like the Coral Triangle, but can be applied at any scale and to other marine ecosystems. PMID:20814570

  6. Optimising Land-Sea Management for Inshore Coral Reefs

    PubMed Central

    Gilby, Ben L.; Olds, Andrew D.; Connolly, Rod M.; Stevens, Tim; Henderson, Christopher J.; Maxwell, Paul S.; Tibbetts, Ian R.; Schoeman, David S.; Rissik, David; Schlacher, Thomas A.

    2016-01-01

    Management authorities seldom have the capacity to comprehensively address the full suite of anthropogenic stressors, particularly in the coastal zone where numerous threats can act simultaneously to impact reefs and other ecosystems. This situation requires tools to prioritise management interventions that result in optimum ecological outcomes under a set of constraints. Here we develop one such tool, introducing a Bayesian Belief Network to model the ecological condition of inshore coral reefs in Moreton Bay (Australia) under a range of management actions. Empirical field data was used to model a suite of possible ecological responses of coral reef assemblages to five key management actions both in the sea (e.g. expansion of reserves, mangrove & seagrass restoration, fishing restrictions) and on land (e.g. lower inputs of sediment and sewage from treatment plants). Models show that expanding marine reserves (a ‘marine action’) and reducing sediment inputs from the catchments (a ‘land action’) were the most effective investments to achieve a better status of reefs in the Bay, with both having been included in >58% of scenarios with positive outcomes, and >98% of the most effective (5th percentile) scenarios. Heightened fishing restrictions, restoring habitats, and reducing nutrient discharges from wastewater treatment plants have additional, albeit smaller effects. There was no evidence that combining individual management actions would consistently produce sizeable synergistic until after maximum investment on both marine reserves (i.e. increasing reserve extent from 31 to 62% of reefs) and sediments (i.e. rehabilitating 6350 km of waterways within catchments to reduce sediment loads by 50%) were implemented. The method presented here provides a useful tool to prioritize environmental actions in situations where multiple competing management interventions exist for coral reefs and in other systems subjected to multiple stressor from the land and the sea

  7. Optimising Land-Sea Management for Inshore Coral Reefs.

    PubMed

    Gilby, Ben L; Olds, Andrew D; Connolly, Rod M; Stevens, Tim; Henderson, Christopher J; Maxwell, Paul S; Tibbetts, Ian R; Schoeman, David S; Rissik, David; Schlacher, Thomas A

    2016-01-01

    Management authorities seldom have the capacity to comprehensively address the full suite of anthropogenic stressors, particularly in the coastal zone where numerous threats can act simultaneously to impact reefs and other ecosystems. This situation requires tools to prioritise management interventions that result in optimum ecological outcomes under a set of constraints. Here we develop one such tool, introducing a Bayesian Belief Network to model the ecological condition of inshore coral reefs in Moreton Bay (Australia) under a range of management actions. Empirical field data was used to model a suite of possible ecological responses of coral reef assemblages to five key management actions both in the sea (e.g. expansion of reserves, mangrove & seagrass restoration, fishing restrictions) and on land (e.g. lower inputs of sediment and sewage from treatment plants). Models show that expanding marine reserves (a 'marine action') and reducing sediment inputs from the catchments (a 'land action') were the most effective investments to achieve a better status of reefs in the Bay, with both having been included in >58% of scenarios with positive outcomes, and >98% of the most effective (5th percentile) scenarios. Heightened fishing restrictions, restoring habitats, and reducing nutrient discharges from wastewater treatment plants have additional, albeit smaller effects. There was no evidence that combining individual management actions would consistently produce sizeable synergistic until after maximum investment on both marine reserves (i.e. increasing reserve extent from 31 to 62% of reefs) and sediments (i.e. rehabilitating 6350 km of waterways within catchments to reduce sediment loads by 50%) were implemented. The method presented here provides a useful tool to prioritize environmental actions in situations where multiple competing management interventions exist for coral reefs and in other systems subjected to multiple stressor from the land and the sea.

  8. Coral communities of the remote atoll reefs in the Nansha Islands, southern South China Sea.

    PubMed

    Zhao, M X; Yu, K F; Shi, Q; Chen, T R; Zhang, H L; Chen, T G

    2013-09-01

    During the months of May and June in the year 2007, a survey was conducted regarding coral reef communities in the remote atolls (Zhubi Reef and Meiji Reef) of Nansha Islands, southern South China Sea. The goals of the survey were to: (1) for the first time, compile a scleractinian coral check-list; (2) estimate the total richness, coral cover, and growth forms of the community; and (3) describe preliminary patterns of community structure according to geomorphological units. Findings of this survey revealed a total of 120 species of scleractinia belonging to 40 genera, while the average coral cover was 21 %, ranging from less than 10 % to higher than 50 %. Branching and massive corals were also found to be the most important growth forms of the whole coral community, while Acropora, Montipora, and Porites were the three dominant genera in the overall region, with their contributions to total coral cover measuring 21, 22, and 23 %, respectively. Overall, coral communities of the Nansha Islands were in a relative healthy condition with high species diversity and coral cover. Spatial pattern of coral communities existed among various geomorphological units. Mean coral cover was highest in the patch reef within the lagoon, followed by the fore reef slope, reef flat, and lagoon slope. The greatest contributors to total coral cover were branching Acropora (45 %) in the lagoon slope, branching Montipora (44 %) in the reef flat, and massive Porites (51 %) in the patch reef. Coral cover in the fore reef revealed a greater range of genera than in other habitats. The leeward fore reef slope had higher coral cover (> 50 %) when compared with the windward slope (< 10 %). The coral communities of the inner reef flat were characterized by higher coral cover (27 %) and dominant branching Montipora corals, while lower coral cover (4 %) was dominated by Psammocora with massive growth forms on the outer reef flat. Destructive fishing and coral bleaching were two major threats to

  9. Rising sea level may cause decline of fringing coral reefs

    NASA Astrophysics Data System (ADS)

    Field, Michael E.; Ogston, Andrea S.; Storlazzi, Curt D.

    2011-08-01

    Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated sea surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but sea level rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century sea level rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that sea level will rise in the coming century (1990-2090) by 2.2-4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of sea level rise [Grinsted et al., 2009; Milne et al., 2009].

  10. Rising sea level may cause decline of fringing coral reefs

    USGS Publications Warehouse

    Field, Michael E.; Ogston, Andrea S.; Storlazzi, Curt D.

    2011-01-01

    Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated sea surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but sea level rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century sea level rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that sea level will rise in the coming century (1990–2090) by 2.2–4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of sea level rise [Grinsted et al., 2009; Milne et al., 2009].

  11. Rising sea level may cause decline of fringing coral reefs

    USGS Publications Warehouse

    Field, M.E.; Ogston, A.S.; Storlazzi, C.D.

    2011-01-01

    Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated sea surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but sea level rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century sea level rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that sea level will rise in the coming century (1990-2090) by 2.2-4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of sea level rise [Grinsted et al., 2009; Milne et al., 2009].

  12. Forecasting decadal changes in sea surface temperatures and coral bleaching within a Caribbean coral reef

    NASA Astrophysics Data System (ADS)

    Li, Angang; Reidenbach, Matthew A.

    2014-09-01

    Elevated sea surface temperature (SST) caused by global warming is one of the major threats to coral reefs. While increased SST has been shown to negatively affect the health of coral reefs by increasing rates of coral bleaching, how changes to atmospheric heating impact SST distributions, modified by local flow environments, has been less understood. This study aimed to simulate future water flow patterns and water surface heating in response to increased air temperature within a coral reef system in Bocas del Toro, Panama, located within the Caribbean Sea. Water flow and SST were modeled using the Delft3D-FLOWcomputer simulation package. Locally measured physical parameters, including bathymetry, astronomic tidal forcing, and coral habitat distribution were input into the model and water flow, and SST was simulated over a four-month period under present day, as well as projected warming scenarios in 2020s, 2050s, and 2080s. Changes in SST, and hence the thermal stress to corals, were quantified by degree heating weeks. Results showed that present-day reported bleaching sites were consistent with localized regions of continuous high SST. Regions with highest SST were located within shallow coastal sites adjacent to the mainland or within the interior of the bay, and characterized by low currents with high water retention times. Under projected increases in SSTs, shallow reef areas in low flow regions were found to be hot spots for future bleaching.

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

    PubMed

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

    2010-05-01

    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. Tectonic subsidence provides insight into possible coral reef futures under rapid sea-level rise

    NASA Astrophysics Data System (ADS)

    Saunders, Megan I.; Albert, Simon; Roelfsema, Chris M.; Leon, Javier X.; Woodroffe, Colin D.; Phinn, Stuart R.; Mumby, Peter J.

    2016-03-01

    Sea-level rise will change environmental conditions on coral reef flats, which comprise extensive habitats in shallow tropical seas and support a wealth of ecosystem services. Rapid relative sea-level rise of 0.6 m over a relatively pristine coral reef in Solomon Islands, caused by a subduction earthquake in April 2007, generated a unique opportunity to examine in situ coral reef response to relative sea-level rise of the magnitude (but not the rate) anticipated by 2100. Extent of live coral was measured from satellite imagery in 2003, 2006, 2009 and 2012. Ecological data were obtained from microatolls and ecological surveys in May 2013. The reef was sampled at 12 locations where dense live hard coral remained absent, remained present or changed from absent to present following subsidence. Ecological data (substratum depth, live coral canopy depth, coral canopy height, substratum suitability, recruitment, diversity and Acropora presence) were measured at each location to identify factors associated with coral response to relative sea-level rise. Vertical and horizontal proliferation of coral occurred following subsidence. Lateral expansion of live coral, accomplished primarily by branching Acropora spp., resulted in lower diversity in regions which changed composition from pavement to dense live coral following subsidence. Of the ecological factors measured, biotic factors were more influential than abiotic factors; species identity was the most important factor in determining which regions of the reef responded to rapid sea-level rise. On relatively pristine reef flats under present climatic conditions, rapid relative sea-level rise generated an opportunity for hard coral to proliferate. However, the species assemblage of the existing reef was important in determining response to sea-level change, by providing previously bare substrate with a source of new coral colonies. Degraded reefs with altered species composition and slower coral growth rates may be less

  15. Sea level record obtained from submerged the Great Barrier Reef coral reefs

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Esat, T. M.; Thompson, W. G.; Thomas, A. L.; Webster, J.; Miyairi, Y.; Matsuzaki, H.; Okuno, J.; Fallon, S.; Braga, J.; Humblet, M.; Iryu, Y.; Potts, D. C.

    2013-12-01

    The last glacial is an interesting time in climate history. The growth and decay of large northern hemisphere ice sheets acting in harmony with major changes in ocean circulation amplified climate variations and resulted in severe and rapid climate swings throughout this time. The variability is not limited to climate but includes rapid, large scale changes in sea level recorded by tropical corals (eg., Yokoyama and Esat, 2011 Oceanography). Research done in the last decade using corals provides a better picture of the climate system, though only a few samples older than 15 ka are available. The Integrated Ocean Drilling Program (IODP) Expedition 325 drilled 34 holes across 17 sites in the Great Barrier Reef, Australia to recover fossil coral reef deposits. We recovered reef materials from water depth to 126 m that ranged in age from 9,000 years to older than 30,000 years ago covering several paleoclimatologically important events, including the Last Glacial Maximum. Two transects separated more than 600 km apart show an identical sea-level history thereby verifying the reliability of the records. Radiometrically dated corals and coralline algae indicate periods of rapid sea-level fluctuation at this time, likely due to complex interactions between ocean currents and ice sheets of the North Atlantic.

  16. Lower Mesophotic Coral Communities (60-125 m Depth) of the Northern Great Barrier Reef and Coral Sea

    PubMed Central

    Englebert, Norbert; Bongaerts, Pim; Muir, Paul R.; Hay, Kyra B.; Pichon, Michel; Hoegh-Guldberg, Ove

    2017-01-01

    Mesophotic coral ecosystems in the Indo-Pacific remain relatively unexplored, particularly at lower mesophotic depths (≥60 m), despite their potentially large spatial extent. Here, we used a remotely operated vehicle to conduct a qualitative assessment of the zooxanthellate coral community at lower mesophotic depths (60–125 m) at 10 different locations in the Great Barrier Reef Marine Park and the Coral Sea Commonwealth Marine Reserve. Lower mesophotic coral communities were present at all 10 locations, with zooxanthellate scleractinian corals extending down to ~100 metres on walls and ~125 m on steep slopes. Lower mesophotic coral communities were most diverse in the 60–80 m zone, while at depths of ≥100 m the coral community consisted almost exclusively of the genus Leptoseris. Collections of coral specimens (n = 213) between 60 and 125 m depth confirmed the presence of at least 29 different species belonging to 18 genera, including several potential new species and geographic/depth range extensions. Overall, this study highlights that lower mesophotic coral ecosystems are likely to be ubiquitous features on the outer reefs of the Great Barrier Reef and atolls of the Coral Sea, and harbour a generic and species richness of corals that is much higher than thus far reported. Further research efforts are urgently required to better understand and manage these ecosystems as part of the Great Barrier Reef Marine Park and Coral Sea Commonwealth Marine Reserve. PMID:28146574

  17. Lower Mesophotic Coral Communities (60-125 m Depth) of the Northern Great Barrier Reef and Coral Sea.

    PubMed

    Englebert, Norbert; Bongaerts, Pim; Muir, Paul R; Hay, Kyra B; Pichon, Michel; Hoegh-Guldberg, Ove

    2017-01-01

    Mesophotic coral ecosystems in the Indo-Pacific remain relatively unexplored, particularly at lower mesophotic depths (≥60 m), despite their potentially large spatial extent. Here, we used a remotely operated vehicle to conduct a qualitative assessment of the zooxanthellate coral community at lower mesophotic depths (60-125 m) at 10 different locations in the Great Barrier Reef Marine Park and the Coral Sea Commonwealth Marine Reserve. Lower mesophotic coral communities were present at all 10 locations, with zooxanthellate scleractinian corals extending down to ~100 metres on walls and ~125 m on steep slopes. Lower mesophotic coral communities were most diverse in the 60-80 m zone, while at depths of ≥100 m the coral community consisted almost exclusively of the genus Leptoseris. Collections of coral specimens (n = 213) between 60 and 125 m depth confirmed the presence of at least 29 different species belonging to 18 genera, including several potential new species and geographic/depth range extensions. Overall, this study highlights that lower mesophotic coral ecosystems are likely to be ubiquitous features on the outer reefs of the Great Barrier Reef and atolls of the Coral Sea, and harbour a generic and species richness of corals that is much higher than thus far reported. Further research efforts are urgently required to better understand and manage these ecosystems as part of the Great Barrier Reef Marine Park and Coral Sea Commonwealth Marine Reserve.

  18. Spatial and seasonal reef calcification in corals and calcareous crusts in the central Red Sea

    NASA Astrophysics Data System (ADS)

    Roik, Anna; Roder, Cornelia; Röthig, Till; Voolstra, Christian R.

    2016-06-01

    The existence of coral reef ecosystems critically relies on the reef carbonate framework produced by scleractinian corals and calcareous crusts (i.e., crustose coralline algae). While the Red Sea harbors one of the longest connected reef systems in the world, detailed calcification data are only available from the northernmost part. To fill this knowledge gap, we measured in situ calcification rates of primary and secondary reef builders in the central Red Sea. We collected data on the major habitat-forming coral genera Porites, Acropora, and Pocillopora and also on calcareous crusts (CC) in a spatio-seasonal framework. The scope of the study comprised sheltered and exposed sites of three reefs along a cross-shelf gradient and over four seasons of the year. Calcification of all coral genera was consistent across the shelf and highest in spring. In addition, Pocillopora showed increased calcification at exposed reef sites. In contrast, CC calcification increased from nearshore, sheltered to offshore, exposed reef sites, but also varied over seasons. Comparing our data to other reef locations, calcification in the Red Sea was in the range of data collected from reefs in the Caribbean and Indo-Pacific; however, Acropora calcification estimates were at the lower end of worldwide rates. Our study shows that the increasing coral cover from nearshore to offshore environments aligned with CC calcification but not coral calcification, highlighting the potentially important role of CC in structuring reef cover and habitats. While coral calcification maxima have been typically observed during summer in many reef locations worldwide, calcification maxima during spring in the central Red Sea indicate that summer temperatures exceed the optima of reef calcifiers in this region. This study provides a foundation for comparative efforts and sets a baseline to quantify impact of future environmental change in the central Red Sea.

  19. Impact of sea-level rise and coral mortality on the wave dynamics and wave forces on barrier reefs.

    PubMed

    Baldock, T E; Golshani, A; Callaghan, D P; Saunders, M I; Mumby, P J

    2014-06-15

    A one-dimensional wave model was used to investigate the reef top wave dynamics across a large suite of idealized reef-lagoon profiles, representing barrier coral reef systems under different sea-level rise (SLR) scenarios. The modeling shows that the impacts of SLR vary spatially and are strongly influenced by the bathymetry of the reef and coral type. A complex response occurs for the wave orbital velocity and forces on corals, such that the changes in the wave dynamics vary reef by reef. Different wave loading regimes on massive and branching corals also leads to contrasting impacts from SLR. For many reef bathymetries, wave orbital velocities increase with SLR and cyclonic wave forces are reduced for certain coral species. These changes may be beneficial to coral health and colony resilience and imply that predicting SLR impacts on coral reefs requires careful consideration of the reef bathymetry and the mix of coral species.

  20. The status of coral reef ecology research in the Red Sea

    NASA Astrophysics Data System (ADS)

    Berumen, M. L.; Hoey, A. S.; Bass, W. H.; Bouwmeester, J.; Catania, D.; Cochran, J. E. M.; Khalil, M. T.; Miyake, S.; Mughal, M. R.; Spaet, J. L. Y.; Saenz-Agudelo, P.

    2013-09-01

    The Red Sea has long been recognized as a region of high biodiversity and endemism. Despite this diversity and early history of scientific work, our understanding of the ecology of coral reefs in the Red Sea has lagged behind that of other large coral reef systems. We carried out a quantitative assessment of ISI-listed research published from the Red Sea in eight specific topics (apex predators, connectivity, coral bleaching, coral reproductive biology, herbivory, marine protected areas, non-coral invertebrates and reef-associated bacteria) and compared the amount of research conducted in the Red Sea to that from Australia's Great Barrier Reef (GBR) and the Caribbean. On average, for these eight topics, the Red Sea had 1/6th the amount of research compared to the GBR and about 1/8th the amount of the Caribbean. Further, more than 50 % of the published research from the Red Sea originated from the Gulf of Aqaba, a small area (<2 % of the area of the Red Sea) in the far northern Red Sea. We summarize the general state of knowledge in these eight topics and highlight the areas of future research priorities for the Red Sea region. Notably, data that could inform science-based management approaches are badly lacking in most Red Sea countries. The Red Sea, as a geologically "young" sea located in one of the warmest regions of the world, has the potential to provide insight into pressing topics such as speciation processes as well as the capacity of reef systems and organisms to adapt to global climate change. As one of the world's most biodiverse coral reef regions, the Red Sea may yet have a significant role to play in our understanding of coral reef ecology at a global scale.

  1. Sea anemones (Cnidaria, Anthozoa, Actiniaria) from coral reefs in the southern Gulf of Mexico.

    PubMed

    González-Muñoz, Ricardo; Simões, Nuno; Tello-Musi, José Luis; Rodríguez, Estefanía

    2013-01-01

    Seven sea anemone species from coral reefs in the southern Gulf of Mexico are taxonomically diagnosed and images from living specimens including external and internal features, and cnidae are provided. Furthermore, the known distribution ranges from another 10 species are extended. No species records of sea anemones have been previously published in the primary scientific literature for coral reefs in the southern Gulf of Mexico and thus, this study represents the first inventory for the local actiniarian fauna.

  2. Sea anemones (Cnidaria, Anthozoa, Actiniaria) from coral reefs in the southern Gulf of Mexico

    PubMed Central

    González-Muñoz, Ricardo; Simões, Nuno; Tello-Musi, José Luis; Rodríguez, Estefanía

    2013-01-01

    Abstract Seven sea anemone species from coral reefs in the southern Gulf of Mexico are taxonomically diagnosed and images from living specimens including external and internal features, and cnidae are provided. Furthermore, the known distribution ranges from another 10 species are extended. No species records of sea anemones have been previously published in the primary scientific literature for coral reefs in the southern Gulf of Mexico and thus, this study represents the first inventory for the local actiniarian fauna. PMID:24146599

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

    PubMed Central

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

    2015-01-01

    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. PMID:26669758

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

    PubMed

    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.

  5. Small change, big difference: Sea surface temperature distributions for tropical coral reef ecosystems, 1950-2011

    NASA Astrophysics Data System (ADS)

    Lough, J. M.

    2012-09-01

    Changes in tropical sea surface temperature (SST) are examined over the period 1950-2011 during which global average temperature warmed by 0.4°C. Average tropical SST is warming about 70% of the global average rate. Spatially, significant warming between the two time periods, 1950-1980 and 1981-2011, has occurred across 65% of the tropical oceans. Coral reef ecosystems occupy 10% of the tropical oceans, typically in regions of warmer (+1.8°C) and less variable SST (80% of months within 3.3°C range) compared to non-reef areas (80% of months within 7.0°C range). SST is a primary controlling factor of coral reef distribution and coral reef organisms have already shown their sensitivity to the relatively small amount of warming observed so far through, for example, more frequent coral bleaching events and outbreaks of coral disease. Experimental evidence is also emerging of possible thermal thresholds in the range 30°C-32°C for some physiological processes of coral reef organisms. Relatively small changes in SST have already resulted in quite large differences in SST distribution with a maximum ‘hot spot’ of change in the near-equatorial Indo-Pacific which encompasses both the Indo-Pacific warm pools and the center of coral reef biodiversity. Identification of this hot spot of SST change is not new but this study highlights its significance with respect to tropical coral reef ecosystems. Given the modest amount of warming to date, changes in SST distribution are of particular concern for coral reefs given additional local anthropogenic stresses on many reefs and ongoing ocean acidification likely to increasingly compromise coral reef processes.

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

    USGS Publications Warehouse

    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.

  7. STS-32 Earth observation of the western Coral Sea and the Great Barrier Reef

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-32 Earth observation taken onboard Columbia, Orbiter Vehicle (OV) 102, is of the western Coral Sea and the Great Barrier Reef. The scene shows phytoplankton or algal bloom in the northwest Coral Sea. The western Coral Sea and the Great Barrier Reef waters offshore Queensland, Australia are the sites of some of the larger concentrations or 'blooms' of phytoplankton and algae in the open ocean. In the instance illustrated here, the leading edge of a probable concentration of algae or phytoplankton is seen as a light irregular line and sheen between the offshore Great Barrier Reef and the Queensland coast. Previous phytoplankton concentrations in this area have been reported by ships at sea as having formed floating mats as thick as two meters.

  8. Kenyan coral reef lagoon fish: effects of fishing, substrate complexity, and sea urchins

    NASA Astrophysics Data System (ADS)

    McClanahan, T. R.

    1994-11-01

    Population density, number of species, diversity, and species-area relationships of fish species in eight common coral reef-associated families were studied in three marine parks receiving total protection from fishing, four sites with unregulated fishing, and one reef which recently received protection from fishing (referred to as a transition reef). Data on coral cover, reef topographic complexity, and sea urchin abundance were collected and correlated with fish abundance and species richness. The most striking result of this survey is a consistent and large reduction in the population density and species richness of 5 families (surgeonfish, triggerfish, butterflyfish, angelfish, and parrotfish). Poor recovery of parrotfish in the transition reef, relative to other fish families, is interpreted as evidence for competitive exclusion of parrotfish by sea urchins. Reef substrate complexity is significantly associated with fish abundance and diversity, but data suggest different responses for protected versus fished reefs, protected reefs having higher species richness and numbers of individuals than unprotected reefs for the same reef complexity. Sea urchin abundance is negatively associated with numbers of fish and fish species but the interrelationship between sea urchins, substrate complexity, coral cover, and management make it difficult to attribute a set percent of variance to each factor-although fishing versus no fishing appears to be the strongest variable in predicting numbers of individuals and species of fish, and their community similarity. Localized species extirpation is evident for many species on fished reefs (for the sampled area of 1.0 ha). Fifty-two of 110 species found on protected reefs were not found on unprotected reefs.

  9. Homogeneity of coral reef communities across 8 degrees of latitude in the Saudi Arabian Red Sea.

    PubMed

    Roberts, May B; Jones, Geoffrey P; McCormick, Mark I; Munday, Philip L; Neale, Stephen; Thorrold, Simon; Robitzch, Vanessa S N; Berumen, Michael L

    2016-04-30

    Coral reef communities between 26.8 °N and 18.6 °N latitude in the Saudi Arabian Red Sea were surveyed to provide baseline data and an assessment of fine-scale biogeography of communities in this region. Forty reefs along 1100 km of coastline were surveyed using depth-stratified visual transects of fish and benthic communities. Fish abundance and benthic cover data were analyzed using multivariate approaches to investigate whether coral reef communities differed with latitude. A total of 215 fish species and 90 benthic categories were recorded on the surveys. There were no significant differences among locations in fish abundance, species richness, or among several diversity indices. Despite known environmental gradients within the Red Sea, the communities remained surprisingly similar. The communities do, however, exhibit subtle changes across this span of reefs that likely reflect the constrained distributions of several species of reef fish and benthic fauna.

  10. Mapping the Rainforest of the Sea: Global Coral Reef Maps for Global Conservation

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.

    2006-01-01

    Coral reefs are the center of marine biodiversity, yet are under threat with an estimated 60% of coral reef habitats considered at risk by the World Resources Institute. The location and extent of coral reefs in the world are the basic information required for resource management and as a baseline for monitoring change. A NASA sponsored partnership between remote sensing scientists, international agencies and NGOs, has developed a new generation of global reef maps based on data collected by satellites. The effort, dubbed the Millennium Coral Reef Map aims to develop new methods for wide distribution of voluminous satellite data of use to the conservation and management communities. We discuss the tradeoffs between remote sensing data sources, mapping objectives, and the needs for conservation and resource management. SeaWiFS data were used to produce a composite global shallow bathymetry map at 1 km resolution. Landsat 7/ETM+ data acquisition plans were modified to collect global reefs and new operational methods were designed to generate the firstever global coral reef geomorphology map. We discuss the challenges encountered to build these databases and in implementing the geospatial data distribution strategies. Conservation applications include a new assessment of the distribution of the world s marine protected areas (UNEPWCMC), improved spatial resolution in the Reefs at Risk analysis for the Caribbean (WRI), and a global basemap for the Census of Marine Life's OBIS database. The Millennium Coral Reef map and digital image archive will pay significant dividends for local and regional conservation projects around the globe. Complete details of the project are available at http://eol.jsc.nasa.gov/reefs.

  11. Direct measurements of air-sea CO2 exchange over a coral reef

    NASA Astrophysics Data System (ADS)

    McGowan, Hamish A.; MacKellar, Mellissa C.; Gray, Michael A.

    2016-05-01

    Quantification of CO2 exchange with the atmosphere over coral reefs has relied on microscale measurements of pCO2 gradients across the air-sea interfacial boundary; shipboard measurements of air-sea CO2 exchange over adjacent ocean inferred to represent over reef processes or ecosystem productivity modeling. Here we present by way of case study the first direct measurements of air-sea CO2 exchange over a coral reef made using the eddy covariance method. Research was conducted during the summer monsoon over a lagoonal platform reef in the southern Great Barrier Reef, Australia. Results show the reef flat to be a net source of CO2 to the atmosphere of similar magnitude as coastal lakes, while adjacent shallow and deep lagoons were net sinks as was the surrounding ocean. This heterogeneity in CO2 exchange with the atmosphere confirms need for spatially representative direct measurements of CO2 over coral reefs to accurately quantify their role in atmospheric carbon budgets.

  12. Remote sensing of sea surface temperatures during 2002 Barrier Reef coral bleaching

    NASA Astrophysics Data System (ADS)

    Liu, Gang; Strong, Alan E.; Skirving, William

    Early in 2002, satellites of the U.S. National Oceanic and Atmospheric Administration (NOAA) detected anomalously high sea surface temperatures (SST) developing in the western Coral Sea, midway along Australia's Great Barrier Reef (GBR). This was the beginning of what was to become the most significant GBR coral bleaching event on record [Wilkinson, 2002]. During this time, NOAA's National Environmental Satellite, Data, and Information Service (NESDIS) provided satellite data as part of ongoing collaborative work on coral reef health with the Australian Institute of Marine Science (AIMS) and the Great Barrier Reef Marine Park Authority (GBRMPA). These data proved invaluable to AIMS and GBRMPA as they monitored and assessed the development and evolution of SSTs throughout the austral summer, enabling them to keep stakeholders, government, and the general public informed and up to date.

  13. Coral Reef Ecosystems

    NASA Astrophysics Data System (ADS)

    Yap, Helen T.

    Coral reefs are geological structures of significant dimensions, constructed over millions of years by calcifying organisms. The present day reef-builders are hard corals belonging to the order Scleractinia, phylum Cnidaria. The greatest concentrations of coral reefs are in the tropics, with highest levels of biodiversity situated in reefs of the Indo-West Pacific region. These ecosystems have provided coastal protection and livelihood to human populations over the millennia. Human activities have caused destruction of these habitats, the intensity of which has increased alarmingly since the latter decades of the twentieth century. The severity of this impact is directly related to exponential growth rates of human populations especially in the coastal areas of the developing world. However, a more recently recognized phenomenon concerns disturbances brought about by the changing climate, manifested mainly as rising sea surface temperatures, and increasing acidification of ocean waters due to greater drawdown of higher concentrations of atmospheric carbon dioxide. Management efforts have so far not kept pace with the rates of degradation, so that the spatial extent of damaged reefs and the incidences of localized extinction of reef species are increasing year after year. The major management efforts to date consist of establishing marine protected areas and promoting the active restoration of coral habitats.

  14. Reef-Fidelity and Migration of Tiger Sharks, Galeocerdo cuvier, across the Coral Sea

    PubMed Central

    Werry, Jonathan M.; Planes, Serge; Berumen, Michael L.; Lee, Kate A.; Braun, Camrin D.; Clua, Eric

    2014-01-01

    Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark–human interactions. Here we compare movement, reef-fidelity, and ocean migration for tiger sharks, Galeocerdo cuvier, across the Coral Sea, with an emphasis on New Caledonia. Thirty-three tiger sharks (1.54 to 3.9 m total length) were tagged with passive acoustic transmitters and their localised movements monitored on receiver arrays in New Caledonia, the Chesterfield and Lord Howe Islands in the Coral Sea, and the east coast of Queensland, Australia. Satellite tags were also used to determine habitat use and movements among habitats across the Coral Sea. Sub-adults and one male adult tiger shark displayed year-round residency in the Chesterfields with two females tagged in the Chesterfields and detected on the Great Barrier Reef, Australia, after 591 and 842 days respectively. In coastal barrier reefs, tiger sharks were transient at acoustic arrays and each individual demonstrated a unique pattern of occurrence. From 2009 to 2013, fourteen sharks with satellite and acoustic tags undertook wide-ranging movements up to 1114 km across the Coral Sea with eight detected back on acoustic arrays up to 405 days after being tagged. Tiger sharks dove 1136 m and utilised three-dimensional activity spaces averaged at 2360 km3. The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks. Management strategies need to consider the wide-ranging movements of large (sub-adult and adult) male and female tiger sharks at the individual level, whereas fidelity to specific coastal reefs may be consistent across groups of individuals. Coastal barrier reef MPAs, however, only afford brief protection for large tiger sharks, therefore determining the importance of other oceanic Coral Sea reefs should be a

  15. Reef-fidelity and migration of tiger sharks, Galeocerdo cuvier, across the Coral Sea.

    PubMed

    Werry, Jonathan M; Planes, Serge; Berumen, Michael L; Lee, Kate A; Braun, Camrin D; Clua, Eric

    2014-01-01

    Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark-human interactions. Here we compare movement, reef-fidelity, and ocean migration for tiger sharks, Galeocerdo cuvier, across the Coral Sea, with an emphasis on New Caledonia. Thirty-three tiger sharks (1.54 to 3.9 m total length) were tagged with passive acoustic transmitters and their localised movements monitored on receiver arrays in New Caledonia, the Chesterfield and Lord Howe Islands in the Coral Sea, and the east coast of Queensland, Australia. Satellite tags were also used to determine habitat use and movements among habitats across the Coral Sea. Sub-adults and one male adult tiger shark displayed year-round residency in the Chesterfields with two females tagged in the Chesterfields and detected on the Great Barrier Reef, Australia, after 591 and 842 days respectively. In coastal barrier reefs, tiger sharks were transient at acoustic arrays and each individual demonstrated a unique pattern of occurrence. From 2009 to 2013, fourteen sharks with satellite and acoustic tags undertook wide-ranging movements up to 1114 km across the Coral Sea with eight detected back on acoustic arrays up to 405 days after being tagged. Tiger sharks dove 1136 m and utilised three-dimensional activity spaces averaged at 2360 km³. The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks. Management strategies need to consider the wide-ranging movements of large (sub-adult and adult) male and female tiger sharks at the individual level, whereas fidelity to specific coastal reefs may be consistent across groups of individuals. Coastal barrier reef MPAs, however, only afford brief protection for large tiger sharks, therefore determining the importance of other oceanic Coral Sea reefs should be a

  16. Genetic relatedness of foraminiferan ( Marginopora vertebralis) populations from reefs in the Western Coral Sea and Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Benzie, John A. H.

    1991-07-01

    Allozyme variation at four loci and phenetic variation for esterase were examined in M. vertebralis populations from 10 reefs from the Western Coral Sea and two from the Great Barrier Reef (GBR). Genetic distances (Nei's D) among populations on different reefs ranged from 0 0.932 and was neither related to geographical separation of reefs nor to depth of water separating reefs. These findings suggest long-distance dispersal by some means is sufficient to prevent genetic differentiation of M. vertebralis populations, and that M. vertebralis populations need not be connected by habitats suitable for the continued existence of the foraminiferan for genetic differentiation to be prevented. The Western Coral Sea reef populations did not form a related group that were genetically distinct from those on the GBR but were differentiated latitudinally. Reefs to the extreme north and south formed outliers while those on the northern half of the Queensland Plateau showed some differentiation from those on the southern half of the Plateau. This pattern of genetic variation appeared to reflect the distribution of populations north and south of the southern limit of the Southern Equatorial Current. Further work will be required to establish the soundness of this relationship, and to exclude other possible explanations related to historical events or the effects of selection. Relatively high dispersal was inferred between the Southern Queensland Plateau reefs and those sampled on the GBR (average Neis D=0.011). Holmes and Marion reefs formed discrete genetic outliers (average Neis D=0.69 and 0.20 respectively). In the case of Holmes reef other factors (e.g. history of recruitment) will need to be investigated to account for its marked genetic differentiation from the other reefs in the Queensland Plateau.

  17. Phytoplankton transport to coral reefs by internal solitons in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Huai

    2016-09-01

    Evidence is presented that waters containing high concentrations of chlorophyll are transported by internal waves to the fore-reef slope of Dongsha Atoll in the northern South China Sea. High vertical resolution mooring measurements of temperature, pressure, and chlorophyll fluorescence revealed that the internal soliton cores could transport chlorophyll vertically downward and increase concentrations by an order of magnitude near the seafloor, compared to background levels. The reef areas that are potentially nourished by the pulses of phytoplankton are dominated by alcyonacean soft corals, while other reef areas that are less or not at all affected by internal waves are dominated by scleractinian hard corals. This suggests that the delivery of phytoplankton by internal solitons provides a plentiful food source that benefits the growth of soft corals.

  18. Hydraulic exchange between a coral reef and surface sea water

    SciTech Connect

    Tribble, G.W.; Sansone, F.J.; Li, Yuan-Hui

    1992-10-01

    Hydraulic exchange between overlying sea water and the internal structure of a patch reef in Kaneohe Bay, Oahu, Hawaii, was studied with an array of wells, 1, 2, and 4 m deep. Two natural chemical tracers, radon, and salinity, were used to calculate the exchange rate between surface sea water and reef interstitial waters. Dissolved radon concentrations are substantially higher in interstitial waters than is surface water. The degree of radon enrichment is quantitatively related to the time elapsed since interstitial water had equilibrated with the atmosphere. Residence time estimates are 1-40 days, with deeper wells having slower exchange. The average residence time for 1-m-deep wells was 2.1 days. A rainstorm-induced dilution of the salinity of Kaneohe Bay provides the second tracer. Samples of surface and reef interstitial waters following this salinity perturbation are used to calculate an average residence time of 2.6 days at a depth of 1 m and 42 days at a depth of 2 m. Three types of physical forces thought to cause exchange between surface and interstitial water are considered by measurement of the forcing functions and reef permeability. Hydraulic conductivities are about 50 m/d, with lower values near the seaward side of the reef. Most exchange seems to be caused by high-frequency, wave-driven oscillatory pumping and by unidirectional hydraulic head gradients (of uncertain origin) that are stable for at least 3-4 days. Wave-driven mixing is probably more important shallower in the reef, whereas head-driven flow may dominate deeper in the reef. Tidal pumping does not seem to contribute to exchange. All methods indicate that exchange in the upper part of Checker Reef is primarily through vertical exchange. The best estimate for the residence time of water at a depth of 1 m is 2 days. Water at depths of 204 m probably has a residence time of weeks to months. 49 refs., 8 figs., 6 tabs.

  19. Coral reef bleaching and sea surface temperature anomalies: 1991-1996 global patterns

    SciTech Connect

    Goreau, T.J.; Hayes, R.L.; Strong, A.

    1997-12-31

    Global spatio-temporal patterns of mass coral reef bleaching during the first half of the 1990s continued to show the strong temperature correlations which first became established in the 1980s. Satellite sea surface temperature data and field observations were used to track thermal bleaching events in real time. Most bleaching events followed warm season sea surface temperature anomalies of around +1 degree celsius above historical means. Global bleaching patterns appear to have been strongly affected by worldwide cooling which followed eruption of Mount Pinatubo in June 1991. High water temperatures and mass coral reef bleaching took place in the Caribbean, Indian Ocean, and South Pacific in 1991, but there were few thermal anomalies or bleaching events in 1992 and 1993, years which were markedly cooler worldwide. Following the settling of Mount Pinatubo aerosols and resumption of global warming trends, extensive ocean thermal hot spots and bleaching events resumed in the South Pacific, South Atlantic, and Indian Oceans in 1994. Bleaching again took place in hot spots in the Indian Ocean and Caribbean in 1995, and in the South Atlantic, Caribbean, South Pacific, North Pacific, and Persian Gulf in 1996. Coral reefs worldwide are now very close to their upper temperature tolerance limits. This sensitivity, and the fact that the warmest ecosystems have no source of immigrant species pre-adapted to warmer conditions, may make coral reef ecosystems the first to be severely impacted if global temperatures and sea levels remain at current values or increase further.

  20. Rapid poleward range expansion of tropical reef corals in response to rising sea surface temperatures

    NASA Astrophysics Data System (ADS)

    Yamano, Hiroya; Sugihara, Kaoru; Nomura, Keiichi

    2011-02-01

    Rising temperatures caused by climatic warming may cause poleward range shifts and/or expansions in species distribution. Tropical reef corals (hereafter corals) are some of the world's most important species, being not only primary producers, but also habitat-forming species, and thus fundamental ecosystem modification is expected according to changes in their distribution. Although most studies of climate change effects on corals have focused on temperature-induced coral bleaching in tropical areas, poleward range shifts and/or expansions may also occur in temperate areas. We show the first large-scale evidence of the poleward range expansion of modern corals, based on 80 years of national records from the temperate areas of Japan, where century-long measurements of in situ sea-surface temperatures have shown statistically significant rises. Four major coral species categories, including two key species for reef formation in tropical areas, showed poleward range expansions since the 1930s, whereas no species demonstrated southward range shrinkage or local extinction. The speed of these expansions reached up to 14 km/year, which is far greater than that for other species. Our results, in combination with recent findings suggesting range expansions of tropical coral-reef associated organisms, strongly suggest that rapid, fundamental modifications of temperate coastal ecosystems could be in progress.

  1. Mineral accretion technology for coral reef restoration, shore protection, and adaptation to rising sea level

    SciTech Connect

    Goreau, T.J.; Hilbertz, W.

    1997-12-31

    Electrolysis of seawater is used to precipitate limestone on top of underwater steel structures to create growing artificial reefs to enhance coral growth, restore coral reef habitat, provide shelter for fish, shellfish, and other marine organisms, generate white sand for beach replenishment, and protect shore lines from wave erosion. Films and slides will be shown of existing structures in Jamaica, Panama, and the Maldives, and projects being developed in these and other locations will be evaluated. The method is unique because it creates the only artificial reef structures that generate the natural limestone substrate from which corals and coral reefs are composed, speeding the settlement and growth of calcareous organisms, and attracting the full range of other reef organisms. The structures are self-repairing and grow stronger with age. Power sources utilized include batteries, battery chargers, photovoltaic panels, and windmills. The cost of seawalls and breakwaters produced by this method is less than one tenth that of conventional technology. Because the technology is readily scaled up to build breakwaters and artificial islands able to keep pace with rising sea level it is capable of playing an important role in protecting low lying coastal areas from the effects of global climate change.

  2. Trace metal anomalies in bleached Porites coral at Meiji Reef, tropical South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Shu; Yu, Kefu; Zhao, Jianxin; Feng, Yuexing; Chen, Tianran

    2017-01-01

    Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium (Cr), copper (Cu), molybdenum (Mo), manganese (Mn), lead (Pb), tin (Sn), titanium (Ti), vanadium (V), and yttrium (Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea (SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events.

  3. High diversity of microplankton surrounds deep-water coral reef in the Norwegian Sea.

    PubMed

    Jensen, Sigmund; Bourne, David G; Hovland, Martin; Murrell, J Colin

    2012-10-01

    Coral reefs that exist in the depths of the oceans are surrounded by Eukarya, Archaea and bacterial communities that may play an important role in the nutrition and health of the reef. The first interdomain community structure of planktonic organisms in seawater from a deep-water coral reef is described. Community profiling and analysis of ribosomal RNA gene sequences from a coral reef system at 350 m depth in the Norwegian Sea revealed a rich diversity of Eukarya and Bacteria and a moderate diversity of Archaea. Most sequences affiliated with marine microplankton from deep-sea to cold-surface regions, with many sequences being similar to those described in studies of mesopelagic and oxygen minimum zones. Dominant phylotypes belonged to the Alveolata (group I, II, dinoflagellates), Stramenopiles (silicoflagellates), Alphaproteobacteria (Pelagibacter ubique), Gammaproteobacteria (ARCTIC96BD-19), Bacteroidetes (Flavobacteria) and mesophilic Crenarchaeota (Nitrosopumilus maritimus). Several rare and novel members of the community fell into distinct phylogenetic groups. The inferred function of dominant community members suggested autotrophs that utilise light, ammonium or sulphide, and lifestyles based on host associations. The high diversity reflected a microplankton community structure, which is significantly different from that of microplankton collected at the same depth at a pelagic station away from reefs.

  4. Hydrodynamic response of a fringing coral reef to a rise in mean sea level

    NASA Astrophysics Data System (ADS)

    Taebi, Soheila; Pattiaratchi, Charitha

    2014-07-01

    Ningaloo Reef, located along the northwest coast of Australia, is one of the longest fringing coral reefs in the world extending ~300 km. Similar to other fringing reefs, it consists of a barrier reef ~1-6 km offshore with occasional gaps, backed by a shallow lagoon. Wave breaking on the reef generates radiation stress gradients that produces wave setup across the reef and lagoon and mean currents across the reef. A section of Ningaloo Reef at Sandy Bay was chosen as the focus of an intense 6-week field experiment and numerical simulation using the wave model SWAN coupled to the three-dimensional circulation model ROMS. The physics of nearshore processes such as wave breaking, wave setup and mean flow across the reef was investigated in detail by examining the various momentum balances established in the system. The magnitude of the terms and the distance of their peaks from reef edge in the momentum balance were sensitive to the changes in mean sea level, e.g. the wave forces decreased as the mean water depth increased (and hence, wave breaking dissipation was reduced). This led to an increase in the wave power at the shoreline, a slight shift of the surf zone to the lee side of the reef and changes in the intensity of the circulation. The predicted hydrodynamic fields were input into a Lagrangian particle tracking model to estimate the transport time scale of the reef-lagoon system. Flushing time of the lagoon with the open ocean was computed using two definitions in renewal of semi-enclosed water basins and revealed the sensitivity of such a transport time scale to methods. An increase in the lagoon exchange rate at smaller mean sea-level rise and the decrease at higher mean sea-level rise was predicted through flushing time computed using both methods.

  5. Trophic ecology of sea urchins in coral-rocky reef systems, Ecuador.

    PubMed

    Cabanillas-Terán, Nancy; Loor-Andrade, Peggy; Rodríguez-Barreras, Ruber; Cortés, Jorge

    2016-01-01

    Sea urchins are important grazers and influence reef development in the Eastern Tropical Pacific (ETP). Diadema mexicanum and Eucidaris thouarsii are the most important sea urchins on the Ecuadorian coastal reefs. This study provided a trophic scenario for these two species of echinoids in the coral-rocky reef bottoms of the Ecuadorian coast, using stable isotopes. We evaluated the relative proportion of algal resources assimilated, and trophic niche of the two sea urchins in the most southern coral-rocky reefs of the ETP in two sites with different disturbance level. Bayesian models were used to estimate the contribution of algal sources, niche breadth, and trophic overlap between the two species. The sea urchins behaved as opportunistic feeders, although they showed differential resource assimilation. Eucidaris thouarsii is the dominant species in disturbed environments; likewise, their niche amplitude was broader than that of D. mexicanum when conditions were not optimal. However, there was no niche overlap between the species. The Stable Isotope Analysis in R (SIAR) indicated that both sea urchins shared limiting resources in the disturbed area, mainly Dictyota spp. (contributions of up to 85% for D. mexicanum and up to 75% for E. thouarsii). The Stable Isotope Bayesian Ellipses in R (SIBER) analysis results indicated less interspecific competition in the undisturbed site. Our results suggested a trophic niche partitioning between sympatric sea urchin species in coastal areas of the ETP, but the limitation of resources could lead to trophic overlap and stronger habitat degradation.

  6. Trophic ecology of sea urchins in coral-rocky reef systems, Ecuador

    PubMed Central

    Loor-Andrade, Peggy; Rodríguez-Barreras, Ruber; Cortés, Jorge

    2016-01-01

    Sea urchins are important grazers and influence reef development in the Eastern Tropical Pacific (ETP). Diadema mexicanum and Eucidaris thouarsii are the most important sea urchins on the Ecuadorian coastal reefs. This study provided a trophic scenario for these two species of echinoids in the coral-rocky reef bottoms of the Ecuadorian coast, using stable isotopes. We evaluated the relative proportion of algal resources assimilated, and trophic niche of the two sea urchins in the most southern coral-rocky reefs of the ETP in two sites with different disturbance level. Bayesian models were used to estimate the contribution of algal sources, niche breadth, and trophic overlap between the two species. The sea urchins behaved as opportunistic feeders, although they showed differential resource assimilation. Eucidaris thouarsii is the dominant species in disturbed environments; likewise, their niche amplitude was broader than that of D. mexicanum when conditions were not optimal. However, there was no niche overlap between the species. The Stable Isotope Analysis in R (SIAR) indicated that both sea urchins shared limiting resources in the disturbed area, mainly Dictyota spp. (contributions of up to 85% for D. mexicanum and up to 75% for E. thouarsii). The Stable Isotope Bayesian Ellipses in R (SIBER) analysis results indicated less interspecific competition in the undisturbed site. Our results suggested a trophic niche partitioning between sympatric sea urchin species in coastal areas of the ETP, but the limitation of resources could lead to trophic overlap and stronger habitat degradation. PMID:26839748

  7. Coral Reef Health Indices versus the Biological, Ecological and Functional Diversity of Fish and Coral Assemblages in the Caribbean Sea.

    PubMed

    Díaz-Pérez, Leopoldo; Rodríguez-Zaragoza, Fabián Alejandro; Ortiz, Marco; Cupul-Magaña, Amílcar Leví; Carriquiry, Jose D; Ríos-Jara, Eduardo; Rodríguez-Troncoso, Alma Paola; García-Rivas, María Del Carmen

    2016-01-01

    This study evaluated the relationship between the indices known as the Reef Health Index (RHI) and two-dimensional Coral Health Index (2D-CHI) and different representative metrics of biological, ecological and functional diversity of fish and corals in 101 reef sites located across seven zones in the western Caribbean Sea. Species richness and average taxonomic distinctness were used to asses biological estimation; while ecological diversity was evaluated with the indices of Shannon diversity and Pielou´s evenness, as well as by taxonomic diversity and distinctness. Functional diversity considered the number of functional groups, the Shannon diversity and the functional Pielou´s evenness. According to the RHI, 57.15% of the zones were classified as presenting a "poor" health grade, while 42.85% were in "critical" grade. Based on the 2D-CHI, 28.5% of the zones were in "degraded" condition and 71.5% were "very degraded". Differences in fish and coral diversity among sites and zones were demonstrated using permutational ANOVAs. Differences between the two health indices (RHI and 2D-CHI) and some indices of biological, ecological and functional diversity of fish and corals were observed; however, only the RHI showed a correlation between the health grades and the species and functional group richness of fish at the scale of sites, and with the species and functional group richness and Shannon diversity of the fish assemblages at the scale of zones. None of the health indices were related to the metrics analyzed for the coral diversity. In general, our study suggests that the estimation of health indices should be complemented with classic community indices, or should at least include diversity indices of fish and corals, in order to improve the accuracy of the estimated health status of coral reefs in the western Caribbean Sea.

  8. Coral Reef Health Indices versus the Biological, Ecological and Functional Diversity of Fish and Coral Assemblages in the Caribbean Sea

    PubMed Central

    Díaz-Pérez, Leopoldo; Ortiz, Marco; Cupul-Magaña, Amílcar Leví; Carriquiry, Jose D.; Ríos-Jara, Eduardo; Rodríguez-Troncoso, Alma Paola; García-Rivas, María del Carmen

    2016-01-01

    This study evaluated the relationship between the indices known as the Reef Health Index (RHI) and two-dimensional Coral Health Index (2D-CHI) and different representative metrics of biological, ecological and functional diversity of fish and corals in 101 reef sites located across seven zones in the western Caribbean Sea. Species richness and average taxonomic distinctness were used to asses biological estimation; while ecological diversity was evaluated with the indices of Shannon diversity and Pielou´s evenness, as well as by taxonomic diversity and distinctness. Functional diversity considered the number of functional groups, the Shannon diversity and the functional Pielou´s evenness. According to the RHI, 57.15% of the zones were classified as presenting a "poor" health grade, while 42.85% were in "critical" grade. Based on the 2D-CHI, 28.5% of the zones were in "degraded" condition and 71.5% were "very degraded". Differences in fish and coral diversity among sites and zones were demonstrated using permutational ANOVAs. Differences between the two health indices (RHI and 2D-CHI) and some indices of biological, ecological and functional diversity of fish and corals were observed; however, only the RHI showed a correlation between the health grades and the species and functional group richness of fish at the scale of sites, and with the species and functional group richness and Shannon diversity of the fish assemblages at the scale of zones. None of the health indices were related to the metrics analyzed for the coral diversity. In general, our study suggests that the estimation of health indices should be complemented with classic community indices, or should at least include diversity indices of fish and corals, in order to improve the accuracy of the estimated health status of coral reefs in the western Caribbean Sea. PMID:27579575

  9. First observations of deep-sea coral reefs along the Angola margin

    NASA Astrophysics Data System (ADS)

    Le Guilloux, E.; Olu, K.; Bourillet, J. F.; Savoye, B.; Iglésias, S. P.; Sibuet, M.

    2009-12-01

    The West African continental slope is an important theatre for geological survey prospecting and drilling for hydrocarbons but little is known about local deep-sea biological communities at these depths. While shallow-water reefs are common and well-known features in the tropics, only few records of deep-water corals exist at low latitudes, and most of them have been reported by historical oceanographic cruises undertaking circum-navigations of the world. This study, based on a multidisciplinary approach, presents a description of newly discovered deep-water coral reef communities along the Angola margin. Data from ROV, multibeam bathymetry, side-scan sonar and seismics from a deep-towed acoustic system (SAR) were used to describe the morphology of the coral mounds and their relationship with the local geological setting. The reef-building scleractinian coral Lophelia pertusa has colonised carbonate mounds that reach heights of ca. 30 m and follow an orientation that is correlated with salt tectonic processes. Recent erosion is suggested as a process that influences the shape of the mounds. Sixteen fish taxa were identified during the ROV video surveys, with some of them likely to have a strong affinity with dense-living corals. The species observed belong to families commonly associated with deep-water corals (i.e. Sebastidae, Berycidae, Lophiidae and Chaunacidae), except an abundant species belonging to the family Zoarcidae, rarely observed in this type of environment. Lucinidae shells were found around mounds. As this bivalve family is indicative of reduced sediment and generally associated with cold-seep environments, this finding could revive the debate over the relationship between the distribution of cold-water coral habitat and gas seeps. However, there is no present-day nutritional relationship between living coral and chemosynthetic-derived biomass. The possible role of fluid expulsion in carbonate precipitation acting as the first step for coral

  10. Please mind the gap - Visual census and cryptic biodiversity assessment at central Red Sea coral reefs.

    PubMed

    Pearman, John K; Anlauf, Holger; Irigoien, Xabier; Carvalho, Susana

    2016-07-01

    Coral reefs harbor the most diverse assemblages in the ocean, however, a large proportion of the diversity is cryptic and, therefore, undetected by standard visual census techniques. Cryptic and exposed communities differ considerably in species composition and ecological function. This study compares three different coral reef assessment protocols: i) visual benthic reef surveys: ii) visual census of Autonomous Reef Monitoring Structures (ARMS) plates; and iii) metabarcoding techniques of the ARMS (including sessile, 106-500 μm and 500-2000 μm size fractions), that target the cryptic and exposed communities of three reefs in the central Red Sea. Visual census showed a dominance of Cnidaria (Anthozoa) and Rhodophyta on the reef substrate, while Porifera, Bryozoa and Rhodophyta were the most abundant groups on the ARMS plates. Metabarcoding, targeting the 18S rRNA gene, significantly increased estimates of the species diversity (p < 0.001); revealing that Annelida were generally the dominant phyla (in terms of reads) of all fractions and reefs. Furthermore, metabarcoding detected microbial eukaryotic groups such as Syndiniophyceae, Mamiellophyceae and Bacillariophyceae as relevant components of the sessile fraction. ANOSIM analysis showed that the three reef sites showed no differences based on the visual census data. Metabarcoding showed a higher sensitivity for identifying differences between reef communities at smaller geographic scales than standard visual census techniques as significant differences in the assemblages were observed amongst the reefs. Comparison of the techniques showed no similar patterns for the visual techniques while the metabarcoding of the ARMS showed similar patterns amongst fractions. Establishing ARMS as a standard tool in reef monitoring will not only advance our understanding of local processes and ecological community response to environmental changes, as different faunal components will provide complementary information but

  11. Coral reef bleaching: ecological perspectives

    NASA Astrophysics Data System (ADS)

    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

  12. Dongsha Atoll: A potential thermal refuge for reef-building corals in the South China Sea.

    PubMed

    Tkachenko, Konstantin S; Soong, Keryea

    2017-04-04

    Dongsha Atoll (also known as the Pratas Islands), the northernmost atoll in the South China Sea, experiences two contrasting physical phenomena: repetitive anomalies of the sea surface temperature exceeding the coral bleaching threshold and regular effects of the world's strongest internal waves resulting in the rhythmic upwelling of cold deep waters at the outer reef slopes of the atoll. This unique combination may result in significant differences in coral species composition and structure between the lagoon and forereef. Surveys conducted in August-September 2016 at 12 study sites in the 2-15 m depth range at Dongsha Atoll revealed a clear spatial separation between 'thermally-susceptible' stony coral genera, including Acropora, Pocillopora and Montipora, which mainly inhabited the forereef, and 'thermally-resistant' genera, including massive Porites, foliaceous Echinopora, Pavona and Turbinaria, which mainly resided in the lagoon. The mean coral cover and species richness on the forereef were respectively 1.8 and 1.4 times higher than those in the lagoon (61.3% and 98 species on the forereef vs. 34.2% and 69 species in the lagoon). Coral mortality rates, expressed as the ratio of dead to live stony corals, showed the same pattern (0.4 in the lagoon vs. 0.009 on the forereef). Furthermore, in a laboratory experiment, 'thermally-susceptible' taxa from the lagoon, (e.g. Pocillopora verrucosa and P. damicornis), exhibited higher resistance to bleaching than did their counterparts from the forereef. The present findings indicate that Dongsha Atoll is a potential thermal refuge for reef-building corals in the northern South China Sea and reveal the development of resilience and resistance to bleaching in coral communities of the lagoon.

  13. Distribution and abundance of sea urchins in Singapore reefs and their potential ecological impacts on macroalgae and coral communities

    NASA Astrophysics Data System (ADS)

    Goh, Beverly P. L.; Lim, Dawn Y. F.

    2015-06-01

    The sea urchin Diadema setosum is often encountered in the coral reefs in the Southern Islands of Singapore. While sea urchins have been known to play a role in regulating algal communities and influencing coral recruitment in other parts of the world, their role in Singapore reefs has not been determined. This study was conducted to determine the distribution and abundance of sea urchins in Singapore reefs, to examine algal cover, algal biomass, algal species and live coral cover, and to determine any interactions between urchin density and algal communities that may impact coral cover. Several reefs in Singapore were surveyed using belt transects measuring 20 m by 2 m, laid down on the reef crest. Abundance of urchins, algal species, biomass, and live coral cover were determined by the use of quadrats within each belt transect. This study revealed an increasing abundance of the sea urchin Diadema setosum in reefs progressing southwards away from mainland Singapore with low density of urchins occurring in Sisters' Island, St John's Island, Pulau Tekukor, and Kusu Island, and the highest density observed at Raffles Lighthouse. A significant negative linear relationship between algal cover and live coral cover (P < 0.05) was established. The results of this study indicate that sea urchins may not be an important component of the herbivore guild in Singapore.

  14. Response of coral reefs to climate change: Expansion and demise of the southernmost Pacific coral reef

    NASA Astrophysics Data System (ADS)

    Woodroffe, Colin D.; Brooke, Brendan P.; Linklater, Michelle; Kennedy, David M.; Jones, Brian G.; Buchanan, Cameron; Mleczko, Richard; Hua, Quan; Zhao, Jian-xin

    2010-08-01

    Coral reefs track sea level and are particularly sensitive to changes in climate. Reefs are threatened by global warming, with many experiencing increased coral bleaching. Warmer sea surface temperatures might enable reef expansion into mid latitudes. Here we report multibeam sonar and coring that reveal an extensive relict coral reef around Lord Howe Island, which is fringed by the southernmost reef in the Pacific Ocean. The relict reef, in water depths of 25-50 m, flourished in early Holocene and covered an area more than 20 times larger than the modern reef. Radiocarbon and uranium-series dating indicates that corals grew between 9000 and 7000 years ago. The reef was subsequently drowned, and backstepped to its modern limited extent. This relict reef, with localised re-establishment of corals in the past three millennia, could become a substrate for reef expansion in response to warmer temperatures, anticipated later this century and beyond, if corals are able to recolonise its surface.

  15. Effects of modeled tropical sea surface temperature variability on coral reef bleaching predictions

    NASA Astrophysics Data System (ADS)

    Van Hooidonk, R. J.

    2011-12-01

    Future widespread coral bleaching and subsequent mortality has been projected with sea surface temperature (SST) data from global, coupled ocean-atmosphere general circulation models (GCMs). While these models possess fidelity in reproducing many aspects of climate, they vary in their ability to correctly capture such parameters as the tropical ocean seasonal cycle and El Niño Southern Oscillation (ENSO) variability. These model weaknesses likely reduce the skill of coral bleaching predictions, but little attention has been paid to the important issue of understanding potential errors and biases, the interaction of these biases with trends and their propagation in predictions. To analyze the relative importance of various types of model errors and biases on coral reef bleaching predictive skill, various intra- and inter-annual frequency bands of observed SSTs were replaced with those frequencies from GCMs 20th century simulations to be included in the Intergovernmental Panel on Climate Change (IPCC) 5th assessment report. Subsequent thermal stress was calculated and predictions of bleaching were made. These predictions were compared with observations of coral bleaching in the period 1982-2007 to calculate skill using an objective measure of forecast quality, the Peirce Skill Score (PSS). This methodology will identify frequency bands that are important to predicting coral bleaching and it will highlight deficiencies in these bands in models. The methodology we describe can be used to improve future climate model derived predictions of coral reef bleaching and it can be used to better characterize the errors and uncertainty in predictions.

  16. Regional hard coral distribution within geomorphic and reef flat ecological zones determined by satellite imagery of the Xisha Islands, South China Sea

    NASA Astrophysics Data System (ADS)

    Zuo, Xiuling; Su, Fenzhen; Zhao, Huanting; Zhang, Junjue; Wang, Qi; Wu, Di

    2016-06-01

    Coral reefs in the Xisha Islands (also known as the Paracel Islands in English), South China Sea, have experienced dramatic declines in coral cover. However, the current regional scale hard coral distribution of geomorphic and ecological zones, essential for reefs management in the context of global warming and ocean acidification, is not well documented. We analyzed data from field surveys, Landsat-8 and GF-1 images to map the distribution of hard coral within geomorphic zones and reef flat ecological zones. In situ surveys conducted in June 2014 on nine reefs provided a complete picture of reef status with regard to live coral diversity, evenness of coral cover and reef health (live versus dead cover) for the Xisha Islands. Mean coral cover was 12.5% in 2014 and damaged reefs seemed to show signs of recovery. Coral cover in sheltered habitats such as lagoon patch reefs and biotic dense zones of reef flats was higher, but there were large regional differences and low diversity. In contrast, the more exposed reef slopes had high coral diversity, along with high and more equal distributions of coral cover. Mean hard coral cover of other zones was <10%. The total Xisha reef system was estimated to cover 1 060 km2, and the emergent reefs covered ~787 m2. Hard corals of emergent reefs were considered to cover 97 km2. The biotic dense zone of the reef flat was a very common zone on all simple atolls, especially the broader northern reef flats. The total cover of live and dead coral can reach above 70% in this zone, showing an equilibrium between live and dead coral as opposed to coral and algae. This information regarding the spatial distribution of hard coral can support and inform the management of Xisha reef ecosystems.

  17. Oceanic inflow from the Coral Sea into the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Brinkman, R.; Wolanski, E.; Deleersnijder, E.; McAllister, F.; Skirving, W.

    2002-04-01

    Long-term current meter data from the continental shelf region of the Great Barrier Reef show that there exists a zone of oceanic inflow onto the shelf. This oceanic inflow splits into two branches on meeting the continental shelf slope, resulting in two net longshore currents on the slope, one to the north and the other to the south of the separation point. In 1981 this separation point was located between 17°S and 18°S. This circulation was successfully predicted using a depth-averaged two-dimensional model in which the regional sea level gradient is explicitly added in the momentum equations. The resulting circulation on the continental shelf is controlled by an oceanic inflow of 0·58 Sv, spread over 500 km of the shelf edge both north and south of the separation point. The inflow appears measurably impeded by the presence of coral reefs, with >50% of the inflow occurring in a 150 km long area where reef density is small. Satellite images confirm this spatial variability. Longshore currents on the shelf generated by the inflow are modulated by the wind and tides, which can deflect the mean current away from areas of high reef density and generate localized outflows to the Coral Sea. Oceanic inflow is believed to be important because it flushes the shelf even in the absence of wind; it controls the dominant direction of across-shelf and along-shelf spread of spawn material from reefs; it makes it possible for upwelled water to spread quickly over the GBR shelf; it may also protect coral reefs by preventing river plumes from spreading onto the outer shelf.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Diagenesis and sea level change in a Pleistocene Coral Reef, San Salvador, Bahamas

    SciTech Connect

    White, B.; Kurkjy, K.A.; Curran, H.A.

    1985-02-01

    Near the Cockburn Town reef (dated 125,000 yr B.P.), precisely surveyed bench marks are related to accurately measured mean sea level, and they provide a convenient datum plane. This coral reef developed during a sea level highstand of no more than 10,000 yr, which was insufficient time for significant subsidence; however, subsidence of approximately 3 m may have occurred since the formation of the reef. Sea level changes were caused by fluctuations in glacial-ice volume. The upper beach to dune transition, which is in the calcarenites overlying the reef, is at +4 m. A minimum highstand of +7 m is indicated when corrected for subsidence. Below +2.5 m, marine aragonite cement occurs within the intragranular pore space of the following: Halimeda plates, benthic foraminifera, Favreina (Callianassid fecal pellets), gastropods, and corals. Marine aragonite cement also occurs as intergranular isopachous rims on matrix grains of coral rubblestone. Remaining pore space was partly to completely occluded by freshwater vadose calcite cements, which occur without marine cements in the overlying shallow subtidal, beach, and dune calcarenites. No unequivocal freshwater phreatic cements, which occur without marine cements in the overlying shallow subtidal, beach, and dune calcarenites. No unequivocal freshwater phreatic cements have been found, although syntaxial overgrowths and irregular calcite rims about grains do occur in finer grained sediments where local patches of freshwater saturation occurred within the vadose zone. Later calchification, which affected all facies, is characterized by alveolar texture, whisker calcite, microsparite, rare bladed calcite spar, Microcodium, and rhizocretions.

  20. Highly heterogeneous bacterial communities associated with the South China Sea reef corals Porites lutea, Galaxea fascicularis and Acropora millepora.

    PubMed

    Li, Jie; Chen, Qi; Zhang, Si; Huang, Hui; Yang, Jian; Tian, Xin-Peng; Long, Li-Juan

    2013-01-01

    Coral harbor diverse and specific bacteria play significant roles in coral holobiont function. Bacteria associated with three of the common and phylogenetically divergent reef-building corals in the South China Sea, Porites lutea, Galaxea fascicularis and Acropora millepora, were investigated using 454 barcoded-pyrosequencing. Three colonies of each species were sampled, and 16S rRNA gene libraries were constructed individually. Analysis of pyrosequencing libraries showed that bacterial communities associated with the three coral species were more diverse than previous estimates based on corals from the Caribbean Sea, Indo-Pacific reefs and the Red Sea. Three candidate phyla, including BRC1, OD1 and SR1, were found for the first time in corals. Bacterial communities were separated into three groups: P. lutea and G. fascicular, A. millepora and seawater. P. lutea and G. fascicular displayed more similar bacterial communities, and bacterial communities associated with A. millepora differed from the other two coral species. The three coral species shared only 22 OTUs, which were distributed in Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and an unclassified bacterial group. The composition of bacterial communities within each colony of each coral species also showed variation. The relatively small common and large specific bacterial communities in these corals implies that bacterial associations may be structured by multiple factors at different scales and that corals may associate with microbes in terms of similar function, rather than identical species.

  1. Seasonal monitoring of coral-algae interactions in fringing reefs of the Gulf of Aqaba, Northern Red Sea

    NASA Astrophysics Data System (ADS)

    Haas, A.; El-Zibdah, M.; Wild, C.

    2010-03-01

    This paper presents seasonal in situ monitoring data on benthic coverage and coral -algae interactions in high-latitude fringing reefs of the Northern Red Sea over a period of 19 months. More than 30% of all hermatypic corals were involved in interaction with benthic reef algae during winter compared to 17% during summer, but significant correlation between the occurrence of coral -algae interactions and monitored environmental factors such as temperature and inorganic nutrient availability was not detected. Between 5 and 10-m water depth, the macroalgae Caulerpa serrulata, Peyssonnelia capensis and filamentous turf algae represented almost 100% of the benthic algae involved in interaction with corals. Turf algae were most frequently (between 77 and 90% of all interactions) involved in interactions with hermatypic corals and caused most tissue damage to them. Maximum coral tissue loss of 0.75% day-1 was observed for Acropora-turf algae interaction during fall, while an equilibrium between both groups of organisms appeared during summer. Slow-growing massive corals were more resistant against negative algal influence than fast-growing branching corals. Branching corals of the genus Acropora partly exhibited a newly observed phenotypic plasticity mechanism, by development of a bulge towards the competing organism, when in interaction with algae. These findings may contribute to understand the dynamics of phase shifts in coral reefs by providing seasonally resolved in situ monitoring data on the abundance and the competitive dynamic of coral -algae interactions.

  2. Genetic structure of giant clam ( Tridacna maxima) populations from reefs in the Western Coral Sea

    NASA Astrophysics Data System (ADS)

    Benzie, John A. H.; Williams, Suzanne T.

    1992-09-01

    Allozyme variation at six polymorphic loci was examined in 10 populations of Tridacna maxima from reefs in the Western Coral Sea, to test whether patterns of relatedness previously reported for foraminiferan populations reflected a fundamental structuring of the fauna in the region. Genetic distances (Nei's D) among populations of T. maxima ranged from 0 0.065 and increased with increasing geographical separation. No significant differences in gene frequencies were observed among populations within two groups of reefs identified by cluster analysis: the Great Barrier Reef (GBR), and among the offshore reefs excluding Lihou and Osprey. Significant genetic differences among these groups and the outliers Lihou and Osprey were consistent with the greater geographical separation of populations between areas than within areas. There was no evidence of differentiation along a north-south axis as reported for the foraminiferan Marginopora vertebralis, nor did populations from offshore reefs on the Queensland Plateau form a well-defined group that was genetically distinct from the GBR. The patterns observed for M. vertebralis do not appear to reflect a fundamental structuring of biota in the region. The differences in the pattern of genetic variation for M. vertebralis as compared with those for T. maxima may be due to several differences in the biological characteristics of the two species. The time of breeding in particular may influence the extent to which the divergence of the East Australian Current restricts larval dispersal among reefs in the central Queensland Plateau.

  3. The future of coral reefs

    NASA Astrophysics Data System (ADS)

    Knowlton, Nancy

    2001-05-01

    Coral reefs, with their millions of species, have changed profoundly because of the effects of people, and will continue to do so for the foreseeable future. Reefs are subject to many of the same processes that affect other human-dominated ecosystems, but some special features merit emphasis: (i) Many dominant reef builders spawn eggs and sperm into the water column, where fertilization occurs. They are thus particularly vulnerable to Allee effects, including potential extinction associated with chronic reproductive failure. (ii) The corals likely to be most resistant to the effects of habitat degradation are small, short-lived "weedy" corals that have limited dispersal capabilities at the larval stage. Habitat degradation, together with habitat fragmentation, will therefore lead to the establishment of genetically isolated clusters of inbreeding corals. (iii) Increases in average sea temperatures by as little as 1°C, a likely result of global climate change, can cause coral "bleaching" (the breakdown of coral-algal symbiosis), changes in symbiont communities, and coral death. (iv) The activities of people near reefs increase both fishing pressure and nutrient inputs. In general, these processes favor more rapidly growing competitors, often fleshy seaweeds, and may also result in explosions of predator populations. (v) Combinations of stress appear to be associated with threshold responses and ecological surprises, including devastating pathogen outbreaks. (vi) The fossil record suggests that corals as a group are more likely to suffer extinctions than some of the groups that associate with them, whose habitat requirements may be less stringent.

  4. The future of coral reefs.

    PubMed

    Knowlton, N

    2001-05-08

    Coral reefs, with their millions of species, have changed profoundly because of the effects of people, and will continue to do so for the foreseeable future. Reefs are subject to many of the same processes that affect other human-dominated ecosystems, but some special features merit emphasis: (i) Many dominant reef builders spawn eggs and sperm into the water column, where fertilization occurs. They are thus particularly vulnerable to Allee effects, including potential extinction associated with chronic reproductive failure. (ii) The corals likely to be most resistant to the effects of habitat degradation are small, short-lived "weedy" corals that have limited dispersal capabilities at the larval stage. Habitat degradation, together with habitat fragmentation, will therefore lead to the establishment of genetically isolated clusters of inbreeding corals. (iii) Increases in average sea temperatures by as little as 1 degrees C, a likely result of global climate change, can cause coral "bleaching" (the breakdown of coral-algal symbiosis), changes in symbiont communities, and coral death. (iv) The activities of people near reefs increase both fishing pressure and nutrient inputs. In general, these processes favor more rapidly growing competitors, often fleshy seaweeds, and may also result in explosions of predator populations. (v) Combinations of stress appear to be associated with threshold responses and ecological surprises, including devastating pathogen outbreaks. (vi) The fossil record suggests that corals as a group are more likely to suffer extinctions than some of the groups that associate with them, whose habitat requirements may be less stringent.

  5. Reproduction of deep-sea reef-building corals from the southwestern Atlantic

    NASA Astrophysics Data System (ADS)

    Pires, D. O.; Silva, J. C.; Bastos, N. D.

    2014-01-01

    The logistics of research on deep-sea organisms imposes restrictions on studies that require repetitive long-term collections. Studies on the reproduction of deep-water corals have commonly been made without appropriate temporal series. This study included Madrepora oculata, Solenosmilia variabilis, Lophelia pertusa, and Enallopsammia rostrata, which are among the primary deep-sea reef building corals off Brazil. Samples were collected during 13 consecutive months by the Campos Basin Deep-Sea Corals Assessment Project (R&D Center of the Brazilian Energy Company, Petrobras) in Campos Basin (CB) off Rio de Janeiro State through a remotely-operated-vehicle at approximately 600 m depth. Of every monthly sampling campaign, an average of four to five colonies of all four species were investigated histologically. Colonies of both sexes were observed, indicating that all four species are gonochoric. For now, this appears to be the predominant reproductive pattern observed in corals in the area, as well as in deep-sea corals in general, where 80% of coral species are gonochoric. Although considered functionally gonochoric, M. oculata and L. pertusa presented a few colonies with different hermaphroditism patterns. E. rostrata and M. oculata presented continuous reproduction. Although fertile year-round, S. variabilis presents a reproductive peak between April and September (Autumn-Spring) in contrast with the seasonal reproduction recorded in the southwestern Pacific. L. pertusa had a seasonal reproductive peak, confirming previous observations of periodic reproduction in this species in the northeastern Atlantic. The possible spawning season of L. pertusa from CB concentrates between May and July (high frequency of mature gametes), while spawning occurs between January and March in the North Atlantic and between September and November in the Gulf of Mexico. Our results suggest that the studied species are broadcast spawners because no embryos or larvae were observed in any

  6. A 6,700 years sea-level record based on French Polynesian coral reefs

    NASA Astrophysics Data System (ADS)

    Hallmann, Nadine; Camoin, Gilbert; Eisenhauer, Anton; Vella, Claude; Samankassou, Elias; Botella, Albéric; Milne, Glenn; Fietzke, Jan; Dussouillez, Philippe

    2015-04-01

    Sea-level change during the Mid- to Late Holocene has a similar amplitude to the sea-level rise that is likely to occur before the end of the 21st century providing a unique opportunity to study the coastal response to sea-level change and to reveal an important baseline of natural climate variability prior to the industrial revolution. Mid- to Late Holocene relative sea-level change in French Polynesia was reconstructed using coral reef records from ten islands, which represent ideal settings for accurate sea-level studies because: 1) they can be regarded as tectonically stable during the relevant period (slow subsidence), 2) they are located far from former ice sheets (far-field), 3) they are characterized by a low tidal amplitude, and 4) they cover a wide range of latitudes which produces significantly improved constraints on GIA (Glacial Isostatic Adjustment) model parameters. Absolute U/Th dating of in situ coral colonies and their accurate positioning via GPS RTK (Real Time Kinematic) measurements is crucial for an accurate reconstruction of sea-level change. We focus mainly on the analysis of coral microatolls, which are sensitive low-tide recorders, as their vertical accretion is limited by the mean low water springs level. Growth pattern analysis allows the reconstruction of low-amplitude, high-frequency sea-level changes on centennial to sub-decadal time scales. A sea-level rise of less than 1 m is recorded between 6 and 3-3.5 ka, and is followed by a gradual fall in sea level that started around 2.5 ka and persisted until the past few centuries. The reconstructed sea-level curve therefore extends the Tahiti sea-level curve [Deschamps et al., 2012, Nature, 483, 559-564], and is in good agreement with a geophysical model tuned to fit far-field deglacial records [Bassett et al., 2005, Science, 309, 925-928].

  7. Miocene reef corals: A review

    SciTech Connect

    Frost, S.H.

    1988-01-01

    Tectonic blockage in the Middle East of westward-flowing Tethys surface circulation during the latest Oligocene led to creation in the earliest Miocene of endemic Mediterranean, Western Atlantic-Caribbean, and Indo-Pacific realms. A great reduction in reef coral diversity from 60-80 Oligocene species to 25-35 early Miocene species occurred in the Western Atlantic-Caribbean and Mediterranean areas accompanied by a decrease in reef growth. A slower and less drastic change apparently occurred in the Indo-Pacific area. Early Miocene reef corals of the Western Atlantic-Caribbean comprise a transition between the cosmopolitan Oligocene fauna and its endemic mid-Miocene to modern counterpart. Although early Miocene reefs were dominated by a Porites-Montastrea assemblage, eastward flow of Pacific circulation brought with it ''exotic'' corals such as Coscinaraea and Pseudocolumnastrea. Also, many cosmopolitan genera persisted from the Oligocene. During the middle to late Miocene, most of the species still living on Holocene reefs evolved. As the Mediterranean basin became more restricted, there was a slow decline in reef corals from 20 - 25 species in the Aquitainian to less than five species in the Messinian. Eustatic lowstand led to the extinction of reef-building corals in the late Messinian. In the Indo-Pacific, Neogene evolution of reef corals was conservative. Excluding the Acroporidae and Seriatoporidae, most Holocene framework species had evolved by the middle Miocene. Interplay between regional tectonics and eustatic sea level changes led to extensive development of middle to late Miocene pinnacle reefs over the southwestern Pacific.

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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.

  10. The distribution and diversity of sea cucumbers in the coral reefs of the South China Sea, Sulu Sea and Sulawesi Sea

    NASA Astrophysics Data System (ADS)

    Woo, Sau Pinn; Yasin, Zulfigar; Ismail, Siti Hasmah; Tan, Shau Hwai

    2013-11-01

    A study on the distribution and diversity of sea cucumbers in the coral reefs of the South China Sea, Sulu Sea and Sulawesi Sea was carried out in July 2009. The survey was done using wandering transect underwater with SCUBA. Twelve species of sea cucumber were found from four different families and nine genera. The most dominant family was Holothuriidae (five species), followed by Stichopodidae (three species), Synaptidae (three species) and Cucumariidae with only one species. The most dominant species found around the island was Pearsonothuria graffei, which can be found abundantly on substrate of dead corals in a wide range of depth (6-15 m). The Sulawesi Sea showed a higher diversity of sea cucumber with seven different species compared to the South China Sea with only six different species and Sulu Sea with only two species. Ordination by multidimensional scaling of Bray-Curtis similarities clustered the sampling locations to three main clusters with two outgroups. Previous studies done indicated a higher diversity of sea cucumber as compared to this study. This can be indication that the population and diversity of sea cucumbers in the reef is under threat.

  11. Coral Reef Remote Sensing Database and Monitoring of Coral Reefs by ASTER

    NASA Astrophysics Data System (ADS)

    Kayanne, H.; Matsunaga, T.; Kanbara, H.; Kato, M.

    2001-05-01

    Coral reefs in the world are under the crisis of degradation both by increasing human activities in coastal zone and by the global changes. All the factors of the global change scenario would bring serious impact on coral reefs. Increase in CO2 suppress calcification in coral reefs. The world-wide bleaching event in 1997-1998 was supposed to be at least partly resulted from global warming. Coral reefs would submerge by sea level rise in this century. To conserve and manage coral reefs against these threats, monitoring of coral reef by satellite remote sensing is important. ASTER has provided effective data for mapping coral reef landforms and benthic communities. The most basic geomorphological and ecological zonation was successfully classified using ASTER data. For example, coral reef flat with its zonation of algai rim, rubble bank, back reef was clearly identified by ASTER by decision tree method and bottom index using VNIR bands data. For the basis of effective monitoring of coral reefs, we have constructed coral reef remote sensing database, which contains more than 1,100,000 data. Tropical and subtropical oceans (40N-40S) were gridded by 0.5 x 0.5 degrees and the grids with coral reefs were identified. The grids with coral reefs correspond to path/rows of the satellite (MOS1, JERS-1, ADEOS, LANDSAT, SPOT and TERRA) and basic information (existence of data, satellite and sensor, path/row, lat/log, aquisition date, cloud cover, type of coral reef) of so-far obtained satellite data until 2000 was input in the database. Status of data aquisition at specific coral reefs can be listed up by this database.

  12. Milankovitch hypothesis supported by precise dating of coral reefs and deep-sea sediments.

    PubMed

    Broecker, W S; Thurber, D L; Goddard, J; Ku, T L; Matthews, R K; Mesolella, K J

    1968-01-19

    Barbados provides a possibly unique opportunity for reconstruction of the times and elevations of late-Pleistocene high stands of the sea. The island appears to be rising from the sea at a uniform rate that is fast enough to separate in elevation coral-reef tracts formed at successive high stands of the sea. Unaltered coral found in the lower terraces enables high-precision Th(230): U(234) and Pa(231): U(235) dating. Three distinct high stands of the sea are found about 122,000, 103,000, and 82,000 years ago. New Pa(231) and Th(230) dates from a deep-sea core also indicate that Ericson's W-X cold-to-warm climatic change occurred close to 126,000 years ago. These data show a parallelism over the last 150,000 years between changes in Earth's climate and changes in the summer insolation predicted from cycles in the tilt and precession of Earth's axis.

  13. In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea

    PubMed Central

    Voolstra, Christian R.; Wild, Christian

    2014-01-01

    In the Central Red Sea, healthy coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost exclusively colonized shaded tiles. Algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if the investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea. PMID:24765573

  14. In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea.

    PubMed

    Jessen, Christian; Voolstra, Christian R; Wild, Christian

    2014-01-01

    In the Central Red Sea, healthy coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost exclusively colonized shaded tiles. Algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if the investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

  15. Tight coupling between coral reef morphology and mapped resilience in the Red Sea.

    PubMed

    Rowlands, Gwilym; Purkis, Sam; Bruckner, Andrew

    2016-04-30

    Lack of knowledge on the conservation value of different reef types can stymie decision making, and result in less optimal management solutions. Addressing the information gap of coral reef resilience, we produce a map-based Remote Sensed Resilience Index (RSRI) from data describing the spatial distribution of stressors, and properties of reef habitats on the Farasan Banks, Saudi Arabia. We contrast the distribution of this index among fourteen reef types, categorized on a scale of maturity that includes juvenile (poorly aggraded), mature (partially aggraded), and senile (fully aggraded) reefs. Sites with high reef resilience can be found in most detached reef types; however they are most common in mature reefs. We aim to stimulate debate on the coupling that exists between geomorphology and conservation biology, and consider how such information can be used to inform management decisions.

  16. Variable Responses of Benthic Communities to Anomalously Warm Sea Temperatures on a High-Latitude Coral Reef

    PubMed Central

    Bryson, Mitch; Hovey, Renae; Figueira, Will F.; Williams, Stefan B.; Pizarro, Oscar; Harborne, Alastair R.; Byrne, Maria

    2014-01-01

    High-latitude reefs support unique ecological communities occurring at the biogeographic boundaries between tropical and temperate marine ecosystems. Due to their lower ambient temperatures, they are regarded as potential refugia for tropical species shifting poleward due to rising sea temperatures. However, acute warming events can cause rapid shifts in the composition of high-latitude reef communities, including range contractions of temperate macroalgae and bleaching-induced mortality in corals. While bleaching has been reported on numerous high-latitude reefs, post-bleaching trajectories of benthic communities are poorly described. Consequently, the longer-term effects of thermal anomalies on high-latitude reefs are difficult to predict. Here, we use an autonomous underwater vehicle to conduct repeated surveys of three 625 m2 plots on a coral-dominated high-latitude reef in the Houtman Abrolhos Islands, Western Australia, over a four-year period spanning a large-magnitude thermal anomaly. Quantification of benthic communities revealed high coral cover (>70%, comprising three main morphospecies) prior to the bleaching event. Plating Montipora was most susceptible to bleaching, but in the plot where it was most abundant, coral cover did not change significantly because of post-bleaching increases in branching Acropora. In the other two plots, coral cover decreased while macroalgal cover increased markedly. Overall, coral cover declined from 73% to 59% over the course of the study, while macroalgal cover increased from 11% to 24%. The significant differences in impacts and post-bleaching trajectories among plots underline the importance of understanding the underlying causes of such variation to improve predictions of how climate change will affect reefs, especially at high-latitudes. PMID:25426718

  17. Variable responses of benthic communities to anomalously warm sea temperatures on a high-latitude coral reef.

    PubMed

    Bridge, Tom C L; Ferrari, Renata; Bryson, Mitch; Hovey, Renae; Figueira, Will F; Williams, Stefan B; Pizarro, Oscar; Harborne, Alastair R; Byrne, Maria

    2014-01-01

    High-latitude reefs support unique ecological communities occurring at the biogeographic boundaries between tropical and temperate marine ecosystems. Due to their lower ambient temperatures, they are regarded as potential refugia for tropical species shifting poleward due to rising sea temperatures. However, acute warming events can cause rapid shifts in the composition of high-latitude reef communities, including range contractions of temperate macroalgae and bleaching-induced mortality in corals. While bleaching has been reported on numerous high-latitude reefs, post-bleaching trajectories of benthic communities are poorly described. Consequently, the longer-term effects of thermal anomalies on high-latitude reefs are difficult to predict. Here, we use an autonomous underwater vehicle to conduct repeated surveys of three 625 m(2) plots on a coral-dominated high-latitude reef in the Houtman Abrolhos Islands, Western Australia, over a four-year period spanning a large-magnitude thermal anomaly. Quantification of benthic communities revealed high coral cover (>70%, comprising three main morphospecies) prior to the bleaching event. Plating Montipora was most susceptible to bleaching, but in the plot where it was most abundant, coral cover did not change significantly because of post-bleaching increases in branching Acropora. In the other two plots, coral cover decreased while macroalgal cover increased markedly. Overall, coral cover declined from 73% to 59% over the course of the study, while macroalgal cover increased from 11% to 24%. The significant differences in impacts and post-bleaching trajectories among plots underline the importance of understanding the underlying causes of such variation to improve predictions of how climate change will affect reefs, especially at high-latitudes.

  18. Numerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport

    USGS Publications Warehouse

    Storlazzi, C.D.; Elias, E.; Field, M.E.; Presto, M.K.

    2011-01-01

    Most climate projections suggest that sea level may rise on the order of 0.5-1.0 m by 2100; it is not clear, however, how fluid flow and sediment dynamics on exposed fringing reefs might change in response to this rapid sea-level rise. Coupled hydrodynamic and sediment-transport numerical modeling is consistent with recent published results that suggest that an increase in water depth on the order of 0.5-1.0 m on a 1-2 m deep exposed fringing reef flat would result in larger significant wave heights and setup, further elevating water depths on the reef flat. Larger waves would generate higher near-bed shear stresses, which, in turn, would result in an increase in both the size and the quantity of sediment that can be resuspended from the seabed or eroded from adjacent coastal plain deposits. Greater wave- and wind-driven currents would develop with increasing water depth, increasing the alongshore and offshore flux of water and sediment from the inner reef flat to the outer reef flat and fore reef where coral growth is typically greatest. Sediment residence time on the fringing reef flat was modeled to decrease exponentially with increasing sea-level rise as the magnitude of sea-level rise approached the mean water depth over the reef flat. The model results presented here suggest that a 0.5-1.0 m rise in sea level will likely increase coastal erosion, mixing and circulation, the amount of sediment resuspended, and the duration of high turbidity on exposed reef flats, resulting in decreased light availability for photosynthesis, increased sediment-induced stress on the reef ecosystem, and potentially affecting a number of other ecological processes.

  19. Effects of modeled tropical sea surface temperature variability on coral reef bleaching predictions

    NASA Astrophysics Data System (ADS)

    van Hooidonk, R.; Huber, M.

    2012-03-01

    Future widespread coral bleaching and subsequent mortality has been projected using sea surface temperature (SST) data derived from global, coupled ocean-atmosphere general circulation models (GCMs). While these models possess fidelity in reproducing many aspects of climate, they vary in their ability to correctly capture such parameters as the tropical ocean seasonal cycle and El Niño Southern Oscillation (ENSO) variability. Such weaknesses most likely reduce the accuracy of predicting coral bleaching, but little attention has been paid to the important issue of understanding potential errors and biases, the interaction of these biases with trends, and their propagation in predictions. To analyze the relative importance of various types of model errors and biases in predicting coral bleaching, various intra- and inter-annual frequency bands of observed SSTs were replaced with those frequencies from 24 GCMs 20th century simulations included in the Intergovernmental Panel on Climate Change (IPCC) 4th assessment report. Subsequent thermal stress was calculated and predictions of bleaching were made. These predictions were compared with observations of coral bleaching in the period 1982-2007 to calculate accuracy using an objective measure of forecast quality, the Peirce skill score (PSS). Major findings are that: (1) predictions are most sensitive to the seasonal cycle and inter-annual variability in the ENSO 24-60 months frequency band and (2) because models tend to understate the seasonal cycle at reef locations, they systematically underestimate future bleaching. The methodology we describe can be used to improve the accuracy of bleaching predictions by characterizing the errors and uncertainties involved in the predictions.

  20. Differential impact of monsoon and large amplitude internal waves on coral reef development in the Andaman Sea.

    PubMed

    Wall, Marlene; Schmidt, Gertraud Maria; Janjang, Pornpan; Khokiattiwong, Somkiat; Richter, Claudio

    2012-01-01

    The Andaman Sea and other macrotidal semi-enclosed tropical seas feature large amplitude internal waves (LAIW). Although LAIW induce strong fluctuations i.e. of temperature, pH, and nutrients, their influence on reef development is so far unknown. A better-known source of disturbance is the monsoon affecting corals due to turbulent mixing and sedimentation. Because in the Andaman Sea both, LAIW and monsoon, act from the same westerly direction their relative contribution to reef development is difficult to discern. Here, we explore the framework development in a number of offshore island locations subjected to differential LAIW- and SW-monsoon impact to address this open question. Cumulative negative temperature anomalies - a proxy for LAIW impact - explained a higher percentage of the variability in coral reef framework height, than sedimentation rates which resulted mainly from the monsoon. Temperature anomalies and sediment grain size provided the best correlation with framework height suggesting that so far neglected subsurface processes (LAIW) play a significant role in shaping coral reefs.

  1. Differential Impact of Monsoon and Large Amplitude Internal Waves on Coral Reef Development in the Andaman Sea

    PubMed Central

    Wall, Marlene; Schmidt, Gertraud Maria; Janjang, Pornpan; Khokiattiwong, Somkiat; Richter, Claudio

    2012-01-01

    The Andaman Sea and other macrotidal semi-enclosed tropical seas feature large amplitude internal waves (LAIW). Although LAIW induce strong fluctuations i.e. of temperature, pH, and nutrients, their influence on reef development is so far unknown. A better-known source of disturbance is the monsoon affecting corals due to turbulent mixing and sedimentation. Because in the Andaman Sea both, LAIW and monsoon, act from the same westerly direction their relative contribution to reef development is difficult to discern. Here, we explore the framework development in a number of offshore island locations subjected to differential LAIW- and SW-monsoon impact to address this open question. Cumulative negative temperature anomalies – a proxy for LAIW impact – explained a higher percentage of the variability in coral reef framework height, than sedimentation rates which resulted mainly from the monsoon. Temperature anomalies and sediment grain size provided the best correlation with framework height suggesting that so far neglected subsurface processes (LAIW) play a significant role in shaping coral reefs. PMID:23209674

  2. Analyzing the Effects of Climate Change on Sea Surface Temperature in Monitoring Coral Reef Health in the Florida Keys Using Sea Surface Temperature Data

    NASA Technical Reports Server (NTRS)

    Jones, Jason; Burbank, Renane; Billiot, Amanda; Schultz, Logan

    2011-01-01

    This presentation discusses use of 4 kilometer satellite-based sea surface temperature (SST) data to monitor and assess coral reef areas of the Florida Keys. There are growing concerns about the impacts of climate change on coral reef systems throughout the world. Satellite remote sensing technology is being used for monitoring coral reef areas with the goal of understanding the climatic and oceanic changes that can lead to coral bleaching events. Elevated SST is a well-documented cause of coral bleaching events. Some coral monitoring studies have used 50 km data from the Advanced Very High Resolution Radiometer (AVHRR) to study the relationships of sea surface temperature anomalies to bleaching events. In partnership with NOAA's Office of National Marine Sanctuaries and the University of South Florida's Institute for Marine Remote Sensing, this project utilized higher resolution SST data from the Terra's Moderate Resolution Imaging Spectroradiometer (MODIS) and AVHRR. SST data for 2000-2010 was employed to compute sea surface temperature anomalies within the study area. The 4 km SST anomaly products enabled visualization of SST levels for known coral bleaching events from 2000-2010.

  3. Coral Reef Biological Criteria

    EPA Science Inventory

    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...

  4. CORAL REEF BIOCRITERIA

    EPA Science Inventory

    Coral reefs worldwide are experiencing the greatest decline of their known existence and few tools are available to offset the growing impacts of human coastal and watershed activities. Biocriteria are a potentially effective means to evaluate and restore impaired waters, but are...

  5. CORAL REEF RESPONSES TO GLOBAL CLIMATE CHANGE

    EPA Science Inventory

    Increased emissions of greenhouse gases and synthetic compounds are related to rising sea temperatures and increased penetration of ultraviolet radiation (UVR), two factors that are consistently linked to bleaching and disease of corals. Coral reefs play a major role in the envir...

  6. Spectral Diversity and Regulation of Coral Fluorescence in a Mesophotic Reef Habitat in the Red Sea

    PubMed Central

    Eyal, Gal; Wiedenmann, Jörg; Grinblat, Mila; D’Angelo, Cecilia; Kramarsky-Winter, Esti; Treibitz, Tali; Ben-Zvi, Or; Shaked, Yonathan; Smith, Tyler B.; Harii, Saki; Denis, Vianney; Noyes, Tim; Tamir, Raz; Loya, Yossi

    2015-01-01

    The phenomenon of coral fluorescence in mesophotic reefs, although well described for shallow waters, remains largely unstudied. We found that representatives of many scleractinian species are brightly fluorescent at depths of 50–60 m at the Interuniversity Institute for Marine Sciences (IUI) reef in Eilat, Israel. Some of these fluorescent species have distribution maxima at mesophotic depths (40–100 m). Several individuals from these depths displayed yellow or orange-red fluorescence, the latter being essentially absent in corals from the shallowest parts of this reef. We demonstrate experimentally that in some cases the production of fluorescent pigments is independent of the exposure to light; while in others, the fluorescence signature is altered or lost when the animals are kept in darkness. Furthermore, we show that green-to-red photoconversion of fluorescent pigments mediated by short-wavelength light can occur also at depths where ultraviolet wavelengths are absent from the underwater light field. Intraspecific colour polymorphisms regarding the colour of the tissue fluorescence, common among shallow water corals, were also observed for mesophotic species. Our results suggest that fluorescent pigments in mesophotic reefs fulfil a distinct biological function and offer promising application potential for coral-reef monitoring and biomedical imaging. PMID:26107282

  7. Spectral Diversity and Regulation of Coral Fluorescence in a Mesophotic Reef Habitat in the Red Sea.

    PubMed

    Eyal, Gal; Wiedenmann, Jörg; Grinblat, Mila; D'Angelo, Cecilia; Kramarsky-Winter, Esti; Treibitz, Tali; Ben-Zvi, Or; Shaked, Yonathan; Smith, Tyler B; Harii, Saki; Denis, Vianney; Noyes, Tim; Tamir, Raz; Loya, Yossi

    2015-01-01

    The phenomenon of coral fluorescence in mesophotic reefs, although well described for shallow waters, remains largely unstudied. We found that representatives of many scleractinian species are brightly fluorescent at depths of 50-60 m at the Interuniversity Institute for Marine Sciences (IUI) reef in Eilat, Israel. Some of these fluorescent species have distribution maxima at mesophotic depths (40-100 m). Several individuals from these depths displayed yellow or orange-red fluorescence, the latter being essentially absent in corals from the shallowest parts of this reef. We demonstrate experimentally that in some cases the production of fluorescent pigments is independent of the exposure to light; while in others, the fluorescence signature is altered or lost when the animals are kept in darkness. Furthermore, we show that green-to-red photoconversion of fluorescent pigments mediated by short-wavelength light can occur also at depths where ultraviolet wavelengths are absent from the underwater light field. Intraspecific colour polymorphisms regarding the colour of the tissue fluorescence, common among shallow water corals, were also observed for mesophotic species. Our results suggest that fluorescent pigments in mesophotic reefs fulfil a distinct biological function and offer promising application potential for coral-reef monitoring and biomedical imaging.

  8. Deep COI sequencing of standardized benthic samples unveils overlooked diversity of Jordanian coral reefs in the northern Red Sea.

    PubMed

    Al-Rshaidat, Mamoon M D; Snider, Allison; Rosebraugh, Sydney; Devine, Amanda M; Devine, Thomas D; Plaisance, Laetitia; Knowlton, Nancy; Leray, Matthieu

    2016-09-01

    High-throughput sequencing (HTS) of DNA barcodes (metabarcoding), particularly when combined with standardized sampling protocols, is one of the most promising approaches for censusing overlooked cryptic invertebrate communities. We present biodiversity estimates based on sequencing of the cytochrome c oxidase subunit 1 (COI) gene for coral reefs of the Gulf of Aqaba, a semi-enclosed system in the northern Red Sea. Samples were obtained from standardized sampling devices (Autonomous Reef Monitoring Structures (ARMS)) deployed for 18 months. DNA barcoding of non-sessile specimens >2 mm revealed 83 OTUs in six phyla, of which only 25% matched a reference sequence in public databases. Metabarcoding of the 2 mm - 500 μm and sessile bulk fractions revealed 1197 OTUs in 15 animal phyla, of which only 4.9% matched reference barcodes. These results highlight the scarcity of COI data for cryptobenthic organisms of the Red Sea. Compared with data obtained using similar methods, our results suggest that Gulf of Aqaba reefs are less diverse than two Pacific coral reefs but much more diverse than an Atlantic oyster reef at a similar latitude. The standardized approaches used here show promise for establishing baseline data on biodiversity, monitoring the impacts of environmental change, and quantifying patterns of diversity at regional and global scales.

  9. Macrobioerosion in Porites corals in subtropical northern South China Sea: a limiting factor for high-latitude reef framework development

    NASA Astrophysics Data System (ADS)

    Chen, Tianran; Li, Shu; Yu, Kefu

    2013-03-01

    Bioerosion is an important limiting factor in carbonate accretion and reef framework development; however, few studies have quantified the direct impact of macroborers on high-latitude coral communities, which are viewed as potential refuge during a period of global warming. In this study, internal macrobioerosion of Porites corals was examined at Daya Bay, subtropical northern South China Sea. The principal borers were the bivalve Lithophaga spp. and the sponges Cliona spp. and Cliothosa spp. (≥80 %), while sipunculid and polychaete worms and barnacles accounted for small amounts of bioerosion (≤20 %). Porites corals were heavily bioeroded in areas impacted by aquacultural and urban activities (10.34-27.55 %) compared with corals in relatively unpolluted areas (2.18-6.76 %). High levels of bioerosion, especially boring bivalve infestation, significantly weaken the corals and increase their susceptibility to dislodgement and fragmentation in typhoons, limiting accumulation of limestone framework. This study implies that carbonate accretion and reef development for high-latitude coral communities may be limited in future high-CO2 and eutrophication-stressed environments.

  10. Ecological intereactions of reef building corals

    EPA Science Inventory

    Coral reefs are very important marine ecosystems because they support tremendous biodiversity and reefs are critical economic resources many coastal nations. Tropical reef structures are largely built by stony corals. This presentation provides background on basic coral biology t...

  11. The effects of sea surface temperature anomalies on oceanic coral reef systems in the southwestern tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Ferreira, B. P.; Costa, M. B. S. F.; Coxey, M. S.; Gaspar, A. L. B.; Veleda, D.; Araujo, M.

    2013-06-01

    In 2010, high sea surface temperatures that were recorded in several parts of the world and caused coral bleaching and coral mortality were also recorded in the southwest Atlantic Ocean, between latitudes 0°S and 8°S. This paper reports on coral bleaching and diseases in Rocas Atoll and Fernando de Noronha archipelago and examines their relationship with sea surface temperature (SST) anomalies recorded by PIRATA buoys located at 8°S30°W, 0°S35°W, and 0°S23°W. Adjusted satellite data were used to derive SST climatological means at buoy sites and to derive anomalies at reef sites. The whole region was affected by the elevated temperature anomaly that persisted through 2010, reaching 1.67 °C above average at reef sites and 1.83 °C above average at buoys sites. A significant positive relationship was found between the percentage of coral bleaching that was observed on reef formations and the corresponding HotSpot SST anomaly recorded by both satellite and buoys. These results indicate that the warming observed in the ocean waters was followed by a warming at the reefs. The percentage of bleached corals persisting after the subsidence of the thermal stress, and disease prevalence increased through 2010, after two periods of thermal stress. The in situ temperature anomaly observed during the 2009-2010 El Niño event was equivalent to the anomaly observed during the 1997-1998 El Niño event, explaining similar bleaching intensity. Continued monitoring efforts are necessary to further assess the relationship between bleaching severity and PIRATA SST anomalies and improve the use of this new dataset in future regional bleaching predictions.

  12. Temporal fluctuations of the Sea Surface Temperature and Chlorophyll-a along of coral reef systems located on the Western coastal zone of the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    de Jesús Salas Pérez, José; Ocaña Valencia, Angel; González Gandara, Carlos

    2014-05-01

    On the coastal zone of the western Gulf of Mexico (GM), there are a variety of coral reef systems which are influenced by river discharge and macro-scale circulation of the GM. The goal of this study is determine if the main fluctuations of the chlorophyll-a and sea surface temperature values (measured from monthly satellite images of sensors Aqua Modis and NOAA-AVHRR in the period of 2008-2011) in coral reef systems, are determined by river discharges or macro-scale circulation of the basin. Moreover determine if the temporal fluctuations of those parameters are correlated between them and thus asses the relationship between them. The most norther coral reef system (Lobos) is classified as mesotrophic-eutrophic. The middle coral reef system (Tuxpan) is ranked as oligotrophic-mesotrophic. Toward the southern region of the western littoral of the GM the coral reefs systems (PNSAV and Coatzacoalcos) are classified as eutrophic. Regarding to Sea Surface Temperature (SST) fluctuations, all coral reef systems showed an almost similar behavior, winter is the season with cool waters (19-23°C). Then in spring, the temperature values increases to about 25°C. Summer season have warm waters (29-30°C). Slightly different, fall decrease their water temperatures to 28°C. The northern coral reef systems (Lobos-Tuxpan) are colder than that the coral reef systems of the southern region (PNSAV-Coatzacoalcos). Those fluctuations, in chlorophyll-a and SST are induced by cyclonic and anticyclonic gyres generated in the Loop current, which impact in the northern region, while the southern region is influenced by river discharge and the presence of a cyclonic gyre of the Campeche bay. But northern and southern coral reef systems are mainly affected by waters of the northern GM advected by winds blowing from the north, mainly in winter.

  13. Unusually high (210)Po activities in the surface water of the Zhubi Coral Reef Lagoon in the South China Sea.

    PubMed

    Yang, Weifeng; Huang, Yipu; Chen, Min; Qiu, Yusheng; Li, Hongbin; Zhang, Lei

    2011-10-01

    Recent researches revealed the exciting application of (210)Po in tracing carbon and nitrogen cycling in the coral reef system. In order to quantify the recycling of particulate organic nitrogen (PON), both (210)Po and (210)Pb were examined at both high and low tides in the Zhubi Coral Reef lagoon, the South China Sea. Unusually, much higher (210)Po activities and (210)Po/(210)Pb ratios, in comparison with those found in the open seawater and the lagoon subsurface water, showed additional input of (210)Po besides production from in situ(210)Pb in the lagoon surface water. Statistical analysis identified that the reef flat seawater was the additional (210)Po source. Based on a mass balance model, the input rates of (210)Po varied from 0.04 Bq m(-3)year(-1) to 8.41 Bq m(-3)year(-1). On average, the additional (210)Po contributed more than 60% of the total (210)Po. The particulate (210)Po significantly correlated with the concentrations of PON, indicating that diffusion of (210)Po from sediment could be used to quantify the recycling of nitrogen. The average input rate of nitrogen was 16 mmol m(-3)year(-1), which can support up to 11% of the primary production rate. These results suggested that the unusual behavior of (210)Po could provide new insight into the nitrogen recycling in the coral reef system.

  14. Spatial distribution of fifty ornamental fish species on coral reefs in the Red Sea and Gulf of Aden

    PubMed Central

    Khalaf, Maroof A.; Abdallah, Mohamed

    2014-01-01

    Abstract The spatial distribution of 50 ornamental fish species from shallow water habitats on coral reefs were investigated using visual census techniques, between latitudes 11−29°N in the Red Sea, in Jordan, Egypt, Saudi Arabia, and Yemen, and in the adjacent Gulf of Aden in Djibouti. One hundred eighteen transects (each 100×5 m) were examined in 29 sites (3−8 sites per country). A total of 522,523 fish individuals were counted during this survey, with mean abundance of 4428.2 ± 87.26 individual per 500 m² transect. In terms of relative abundance (RA), the most abundant species were Blue green damselfish, Chromis viridis (RA=54.4%),followed bySea goldie, Pseudanthias squamipinnis (RA= 34.7), Whitetail dascyllus, Dascyllus aruanus (RA= 2.6%), Marginate dascyllus, Dascyllus marginatus (RA= 2.0),Red Sea eightline flasher Paracheilinus octotaenia (RA=1.0),andKlunzinger’s wrasse, Thalassoma rueppellii (0.7%). The highest number of species (S) per 500 m² transect was found on reefs at the latitude 20° in Saudi Arabia (S=21.8), and the lowest number of species was found at the latitude 15° in Djibouti (S=11.11). The highest mean abundance (8565.8) was found on reefs at latitude 20° in Saudi Arabia and the lowest mean abundance (230) was found on reefs at latitude 22°, also in Saudi Arabia. Whereas, the highest Shannon-Wiener Diversity Index was found in reefs at the latitude 22° (H`=2.4) and the lowest was found in reefs at the latitude 20° (H`=0.6). This study revealed marked differences in the structure of ornamental fish assemblages with latitudinal distribution. The data support the presence of two major biogeographic groups of fishes in the Red Sea and Gulf of Aden: the southern Red Sea and Gulf of Aden group and the group in the northern and central Red Sea. Strong correlations were found between live coral cover and the number of fish species, abundance and Shannon-Wiener Diversity indices, and the strength of these correlations varied among the

  15. Spatial distribution of fifty ornamental fish species on coral reefs in the Red Sea and Gulf of Aden.

    PubMed

    Khalaf, Maroof A; Abdallah, Mohamed

    2014-01-01

    The spatial distribution of 50 ornamental fish species from shallow water habitats on coral reefs were investigated using visual census techniques, between latitudes 11-29°N in the Red Sea, in Jordan, Egypt, Saudi Arabia, and Yemen, and in the adjacent Gulf of Aden in Djibouti. One hundred eighteen transects (each 100×5 m) were examined in 29 sites (3-8 sites per country). A total of 522,523 fish individuals were counted during this survey, with mean abundance of 4428.2 ± 87.26 individual per 500 m² transect. In terms of relative abundance (RA), the most abundant species were Blue green damselfish, Chromis viridis (RA=54.4%),followed bySea goldie, Pseudanthias squamipinnis (RA= 34.7), Whitetail dascyllus, Dascyllus aruanus (RA= 2.6%), Marginate dascyllus, Dascyllus marginatus (RA= 2.0),Red Sea eightline flasher Paracheilinus octotaenia (RA=1.0),andKlunzinger's wrasse, Thalassoma rueppellii (0.7%). The highest number of species (S) per 500 m² transect was found on reefs at the latitude 20° in Saudi Arabia (S=21.8), and the lowest number of species was found at the latitude 15° in Djibouti (S=11.11). The highest mean abundance (8565.8) was found on reefs at latitude 20° in Saudi Arabia and the lowest mean abundance (230) was found on reefs at latitude 22°, also in Saudi Arabia. Whereas, the highest Shannon-Wiener Diversity Index was found in reefs at the latitude 22° (H`=2.4) and the lowest was found in reefs at the latitude 20° (H`=0.6). This study revealed marked differences in the structure of ornamental fish assemblages with latitudinal distribution. The data support the presence of two major biogeographic groups of fishes in the Red Sea and Gulf of Aden: the southern Red Sea and Gulf of Aden group and the group in the northern and central Red Sea. Strong correlations were found between live coral cover and the number of fish species, abundance and Shannon-Wiener Diversity indices, and the strength of these correlations varied among the reefs. A

  16. Habitat characterization of deep-water coral reefs in La Gaviera Canyon (Avilés Canyon System, Cantabrian Sea)

    NASA Astrophysics Data System (ADS)

    Sánchez, Francisco; González-Pola, Cesar; Druet, María; García-Alegre, Ana; Acosta, Juan; Cristobo, Javier; Parra, Santiago; Ríos, Pilar; Altuna, Álvaro; Gómez-Ballesteros, María; Muñoz-Recio, Araceli; Rivera, Jesus; del Río, Guillermo Díaz

    2014-08-01

    Surveys conducted at the complex Avilés Canyon System (southern Bay of Biscay) in order to identify vulnerable habitats and biological communities revealed the presence of noteworthy deep-water coral reefs in one of the tributaries of the system (La Gaviera Canyon). The aim of the present study is to determine why this deep-sea canyon provides suitable environmental conditions for corals to grow. This hanging canyon is characterized by an irregular U-shaped floor with two narrow differentiated flanks. Sand ripples and rocky outcrops structured in diverse W-E directed steps are observed on the canyon floor, suggesting intense hydrodynamic activity. Accordingly, high-frequency near-bottom current and thermal structure profiles showed that there occur strong shifts in currents/hydrography behaving as front-like features at each tidal cycle. These involve the sudden increase of along-axis velocities to over 50 cm/s and vertical velocities of over 5 cm/s in each tidal cycle associated with the passage of sharp thermal fronts and thermal inversions suggesting overturning. A year-long near-bottom current record showed events with near-bottom velocities well over 1 m/s lasting for several days. Three cold-water coral settings were distinguished: a dense coral reef located on stepped rocky bottoms of the eastern and western flanks, carbonate mounds (20-30 m high) located on the canyon floor, and a cluster of shallower water dead coral framework at the head sector of the canyon. Video and still images from a towed sled and ROV verified the presence of dropstones and rippled sand sheets surrounding the mounds and revealed changes in the coral population (alive or dead; total or patchy coverage) in coral reef and carbonate mound areas. The dominant species of the reef are Lophelia pertusa and Madrepora oculata, which considerably increase the habitat‧s complexity and biodiversity in relation to other facies described in the canyon. The presence of living cold-water reefs is

  17. Assessing the potential for tropical cyclone induced sea surface cooling to reduce thermal stress on the world's coral reefs

    NASA Astrophysics Data System (ADS)

    Carrigan, A. D.; Puotinen, M. L.

    2011-12-01

    Coral reefs face an uncertain future as rising sea surface temperature (SST) continues to lead to increasingly frequent and intense mass bleaching. At broad spatial scales, tropical cyclone (TC) induced cooling of the upper ocean (SST drops up to 6° C persisting for weeks) reduces thermal stress and accelerates recovery of bleached corals - yet the global prevalence and spatial distribution of this effect remains undocumented and unquantified. A global dataset (1985-2009) of TC wind exposure was constructed and examined against existing thermal stress data to address this. Significant correlations were found between TC activity and the severity of thermal stress at various spatial scales, particularly for Caribbean reefs. From this, it is apparent that TCs play a role in bleaching dynamics at a global scale. However, the prevalence and distribution of this interaction varies by region and requires further examination at finer spatial and temporal scales using actual SST data.

  18. Coral reef resilience through biodiversity

    USGS Publications Warehouse

    Rogers, Caroline S.

    2013-01-01

    Irrefutable evidence of coral reef degradation worldwide and increasing pressure from rising seawater temperatures and ocean acidification associated with climate change have led to a focus on reef resilience and a call to “manage” coral reefs for resilience. Ideally, global action to reduce emission of carbon dioxide and other greenhouse gases will be accompanied by local action. Effective management requires reduction of local stressors, identification of the characteristics of resilient reefs, and design of marine protected area networks that include potentially resilient reefs. Future research is needed on how stressors interact, on how climate change will affect corals, fish, and other reef organisms as well as overall biodiversity, and on basic ecological processes such as connectivity. Not all reef species and reefs will respond similarly to local and global stressors. Because reef-building corals and other organisms have some potential to adapt to environmental changes, coral reefs will likely persist in spite of the unprecedented combination of stressors currently affecting them. The biodiversity of coral reefs is the basis for their remarkable beauty and for the benefits they provide to society. The extraordinary complexity of these ecosystems makes it both more difficult to predict their future and more likely they will have a future.

  19. Coral reef evolution on rapidly subsiding margins

    USGS Publications Warehouse

    Webster, J.M.; Braga, J.C.; Clague, D.A.; Gallup, C.; Hein, J.R.; Potts, D.C.; Renema, W.; Riding, R.; Riker-Coleman, K.; Silver, E.; Wallace, L.M.

    2009-01-01

    A series of well-developed submerged coral reefs are preserved in the Huon Gulf (Papua New Guinea) and around Hawaii. Despite different tectonics settings, both regions have experienced rapid subsidence (2-6??m/ka) over the last 500??ka. Rapid subsidence, combined with eustatic sea-level changes, is responsible for repeated drowning and backstepping of coral reefs over this period. Because we can place quantitative constraints on these systems (i.e., reef drowning age, eustatic sea-level changes, subsidence rates, accretion rates, basement substrates, and paleobathymetry), these areas represent unique natural laboratories for exploring the roles of tectonics, reef accretion, and eustatic sea-level changes in controlling the evolution of individual reefs, as well as backstepping of the entire system. A review of new and existing bathymetric, radiometric, sedimentary facies and numerical modeling data indicate that these reefs have had long, complex growth histories and that they are highly sensitive, recording drowning not only during major deglaciations, but also during high-frequency, small-amplitude interstadial and deglacial meltwater pulse events. Analysis of five generalized sedimentary facies shows that reef drowning is characterized by a distinct biological and sedimentary sequence. Observational and numerical modeling data indicate that on precessional (20??ka) and sub-orbital timescales, the rate and amplitude of eustatic sea-level changes are critical in controlling initiation, growth, drowning or sub-aerial exposure, subsequent re-initiation, and final drowning. However, over longer timescales (> 100-500??ka) continued tectonic subsidence and basement substrate morphology influence broad scale reef morphology and backstepping geometries. Drilling of these reefs will yield greatly expanded stratigraphic sections compared with similar reefs on slowly subsiding, stable and uplifting margins, and thus they represent a unique archive of sea-level and climate

  20. Basin-scale estimates of pelagic and coral reef calcification in the Red Sea and Western Indian Ocean

    PubMed Central

    Steiner, Zvi; Erez, Jonathan; Shemesh, Aldo; Yam, Ruth; Katz, Amitai; Lazar, Boaz

    2014-01-01

    Basin-scale calcification rates are highly important in assessments of the global oceanic carbon cycle. Traditionally, such estimates were based on rates of sedimentation measured with sediment traps or in deep sea cores. Here we estimated CaCO3 precipitation rates in the surface water of the Red Sea from total alkalinity depletion along their axial flow using the water flux in the straits of Bab el Mandeb. The relative contribution of coral reefs and open sea plankton were calculated by fitting a Rayleigh distillation model to the increase in the strontium to calcium ratio. We estimate the net amount of CaCO3 precipitated in the Red Sea to be 7.3 ± 0.4·1010 kg·y−1 of which 80 ± 5% is by pelagic calcareous plankton and 20 ± 5% is by the flourishing coastal coral reefs. This estimate for pelagic calcification rate is up to 40% higher than published sedimentary CaCO3 accumulation rates for the region. The calcification rate of the Gulf of Aden was estimated by the Rayleigh model to be ∼1/2 of the Red Sea, and in the northwestern Indian Ocean, it was smaller than our detection limit. The results of this study suggest that variations of major ions on a basin scale may potentially help in assessing long-term effects of ocean acidification on carbonate deposition by marine organisms. PMID:25368148

  1. Basin-scale estimates of pelagic and coral reef calcification in the Red Sea and Western Indian Ocean.

    PubMed

    Steiner, Zvi; Erez, Jonathan; Shemesh, Aldo; Yam, Ruth; Katz, Amitai; Lazar, Boaz

    2014-11-18

    Basin-scale calcification rates are highly important in assessments of the global oceanic carbon cycle. Traditionally, such estimates were based on rates of sedimentation measured with sediment traps or in deep sea cores. Here we estimated CaCO3 precipitation rates in the surface water of the Red Sea from total alkalinity depletion along their axial flow using the water flux in the straits of Bab el Mandeb. The relative contribution of coral reefs and open sea plankton were calculated by fitting a Rayleigh distillation model to the increase in the strontium to calcium ratio. We estimate the net amount of CaCO3 precipitated in the Red Sea to be 7.3 ± 0.4·10(10) kg·y(-1) of which 80 ± 5% is by pelagic calcareous plankton and 20 ± 5% is by the flourishing coastal coral reefs. This estimate for pelagic calcification rate is up to 40% higher than published sedimentary CaCO3 accumulation rates for the region. The calcification rate of the Gulf of Aden was estimated by the Rayleigh model to be ∼1/2 of the Red Sea, and in the northwestern Indian Ocean, it was smaller than our detection limit. The results of this study suggest that variations of major ions on a basin scale may potentially help in assessing long-term effects of ocean acidification on carbonate deposition by marine organisms.

  2. Coral reefs and carbon dioxide

    SciTech Connect

    Buddemeier, R.W.

    1996-03-01

    This commentary argues the conclusion from a previous article, which investigates diurnal changes in carbon dioxide partial pressure and community metabolism on coral reefs, that coral `reefs might serve as a sink, not a source, for atmospheric carbon dioxide.` Commentaries from two groups are given along with the response by the original authors, Kayanne et al. 27 refs.

  3. Maintenance of fish diversity on disturbed coral reefs

    NASA Astrophysics Data System (ADS)

    Wilson, S. K.; Dolman, A. M.; Cheal, A. J.; Emslie, M. J.; Pratchett, M. S.; Sweatman, H. P. A.

    2009-03-01

    Habitat perturbations play a major role in shaping community structure; however, the elements of disturbance-related habitat change that affect diversity are not always apparent. This study examined the effects of habitat disturbances on species richness of coral reef fish assemblages using annual surveys of habitat and 210 fish species from 10 reefs on the Great Barrier Reef (GBR). Over a period of 11 years, major disturbances, including localised outbreaks of crown-of-thorns sea star ( Acanthaster planci), severe storms or coral bleaching, resulted in coral decline of 46-96% in all the 10 reefs. Despite declines in coral cover, structural complexity of the reef framework was retained on five and species richness of coral reef fishes maintained on nine of the disturbed reefs. Extensive loss of coral resulted in localised declines of highly specialised coral-dependent species, but this loss of diversity was more than compensated for by increases in the number of species that feed on the epilithic algal matrix (EAM). A unimodal relationship between areal coral cover and species richness indicated species richness was greatest at approximately 20% coral cover declining by 3-4 species (6-8% of average richness) at higher and lower coral cover. Results revealed that declines in coral cover on reefs may have limited short-term impact on the diversity of coral reef fishes, though there may be fundamental changes in the community structure of fishes.

  4. Community dynamics of Pleistocene coral reefs during alternative climatic regimes.

    PubMed

    Tager, Danika; Webster, Jody M; Potts, Donald C; Renema, Willem; Braga, Juan C; Pandolfi, John M

    2010-01-01

    Reef ecosystems built during successive periods of Pleistocene sea level rise have shown remarkable persistence in coral community structure, but little is known of the ecological characteristics of reef communities during periods of low sea stands or sea level falls. We sampled the relative species abundance of coral, benthic foraminifera, and calcareous red algae communities from eight submerged coral reefs in the Huon Gulf, Papua New Guinea, which formed during successive sea level fall and lowstand periods over the past approximately kyr. We found that dissimilarity in coral species composition increased significantly with increasing time between reef-building events. However, neither coral diversity nor the taxonomic composition of benthic foraminifera and calcareous red algae assemblages varied significantly over time. The taxonomic composition of coral communities from lowstand reefs was significantly different from that of highstand reefs previously reported from the nearby Huon Peninsula. We interpret the community composition and temporal dynamics of lowstand reefs as a result of shifting energy regimes in the Huon Gulf, and differences between low and highstand reefs as a result of differences in the interaction between biotic and environmental factors between the Huon Gulf and Huon Peninsula. Regardless of the exact processes driving these trends, our study represents the first glimpse into the ecological dynamics of coral reefs during low sea level stands when climatic conditions for reef growth were much different and less optimal than during previously studied highstand periods.

  5. Reconstruction of Late Holocene sea-level change in French Polynesia, South Pacific, based on coral reef records

    NASA Astrophysics Data System (ADS)

    Hallmann, Nadine; Camoin, Gilbert; Eisenhauer, Anton; Vella, Claude

    2013-04-01

    Fossil reefs provide valuable sea-level indicators, which help to improve the understanding of past sea-level fluctuations and the prediction of future changes. Recent sea-level changes were reconstructed from emerged reef platforms of two high islands from the Society Islands (Bora Bora, Moorea) and two atolls from the Tuamotu Archipelago (Rangiroa, Tikehau), French Polynesia. These mid-ocean islands can be regarded as tectonically stable for the past few thousand years. Therefore, they are well suited for sea-level studies because they register Holocene eustatic changes, which are not overprinted by tectonic changes. Furthermore, the study sites are located distant from former ice sheets (far field location), which reduces the influence of the glacio-isostatic rebound. Several sea-level indicators, such as in situ coral colonies, including coral microatolls (Porites sp.), bivalves (mainly Tridacna sp.), conglomerates, beachrock, and sediments were analyzed in order to reconstruct Late Holocene relative sea-level changes. Microatolls are discoid corals that develop laterally when upward growth is limited by sea-level. Therefore, they are very accurate recorders of past sea-level. This study provides a detailed sea-level history for French Polynesia using high-precision U/Th (TIMS) dating and GPS measurements with a vertical and horizontal precision of 1-3 cm and a few millimetres, respectively. All samples were analyzed by X-ray diffraction and examined petrographically to exclude diagenetically altered material. The Holocene mean sea level in French Polynesia was thought to have been higher than present (+0.8/+1.0 m) between 5000 and 1250 yr BP, reached a highstand between 2000 and 1500 yr BP and then decreased to the present level (Pirazzoli and Montaggioni, 1988). The highstand has been reported until 1200 yr BP in the Tuamotu Archipelago (Pirazzoli and Montaggioni, 1986). However, sea-level indicators analyzed in this study reveal a highstand of at least 1.5 m

  6. Bioindication in coral reef ecosystems.

    PubMed

    Yap, H T

    1986-01-01

    The concept of bioindication in the sense of the use of organisms for detecting environmental stress has been employed in coral reef conservation and management for the past several years. Important tools are coral growth rates and various community parameters, notably hard coral cover. The present need is the optimal coordination of international efforts for the earliest possible institution of an effective monitoring system.

  7. 280-year Long Sr/Ca and δ 18O Records From Flinders Reef, Western Coral Sea

    NASA Astrophysics Data System (ADS)

    Calvo, E.; Marshall, J. F.; Pelejero, C.; McCulloch, M. T.; Lough, J.; Gagan, M. K.

    2003-12-01

    The combination of parallel Sr/Ca and δ 18O records in corals allows reconstruction of past changes in sea surface temperature (SST) and seawater δ 18O composition (McCulloch et al., 1994). The latter provides climatic information related to changes in the hydrologic cycle and can be interpreted as a salinity proxy. Since the δ 18O signal is affected by both SST and seawater isotopic composition, a salinity record can be obtained by removing the temperature signal using a parallel Sr/Ca record, a proxy for SST, obtained from the same coral. Low resolution (5-year intervals) Sr/Ca and δ 18O analyses, going back to 1710 AD, have been performed on a Porites coral core collected from Flinders Reef, an offshore reef on the Queensland Plateau (17° S, 149° E), 250 km from the north-east coast of Australia. For the last 280 years, the preliminary Sr/Ca-SST record shows an increasing long-term trend towards the warm temperatures recorded during 1990, when the coral was collected. An increasing trend towards more negative δ 18O values (warmer and/or less saline conditions) is also observed in the isotopic record, which also reflects the 20th century warming. Despite this general common trend, interdecadal variability differences between both records suggest that temperature alone cannot explain the δ 18O changes observed in this site of the Coral Sea. A freshening of surface waters after 1870 has recently been reported from coral cores collected from the inshore region in the Great Barrier Reef and interpreted as indicating a weakening in trade winds and ocean circulation (Hendy, 2002). In the Flinders coral, however, an apparent freshening occurs in the early 1800s, followed by a subsequent transition to more saline conditions during the first half of the 20th century. Our data will be compared to that from the GBR and elsewhere in the SW Pacific (Quinn, 1998). Hendy, E. J. et al. Science 295, 1511-1514 (2002) McCulloch, M.T. et al. Geochimica at Cosmochimica Acta

  8. Disease of coral and coral reef fishes

    USGS Publications Warehouse

    Panek, Frank

    2008-01-01

    The Department of the Interior protects sensitive habitats amounting to about 3,600,000 acres of coral reefs and other submerged lands. These reefs are important ecosystems in 13 National Wildlife Refuges, 10 National Parks and in certain territorial waters such as the Wake Atoll.

  9. Coral reef hydrogeology

    SciTech Connect

    Buddemeier, R.W.; Oberdorfer, J.A.

    1985-05-21

    Knowledge of internal flow velocities and pore water residence time is important in understanding pore water geochemistry, nutrient fluxes at the benthic boundary, reef diagenesis, and fresh water resources in reef islands. Hydrogeologic studies of Pacific and Indian Ocean reef and atoll islands indicate a dual aquifer systems; the major Pleistocene aquifer has hydraulic conductivities on the order of 1000 m/d, while the overlying Holocene aquifer of unconsolidated sediments is at least an order of magnitude less permeable. The high permeability in the Pleistocene formation is the result of large voids, both constructional and from subaerial solution during low stands of the sea. Wind, wave and tide induced head differences ranging from a few centimeters to several tens of centimeters provide the driving force for internal flow. Pore water residence times and geochemistry will vary greatly, depending on whether the water is in a major flow channel or in more restricted pores. Studies of both submerged reefs and atoll islands give bulk pore water residence times on the order of months to a few years. Chemical analyses of pore water indicate that both carbonate solution and precipitation are taking place, which will alter porosity and permeability with time. The dual aquifer model also suggests that the Ghyben-Herzberg lens approach to reef island fresh water resources is inaccurate and can lead to a gross overestimation of the potable resource. 18 refs., 5 figs.

  10. Wave transformation over coral reefs

    NASA Astrophysics Data System (ADS)

    Young, Ian R.

    1989-07-01

    Ocean wave attenuation on coral reefs is discussed using data obtained from a preliminary field experiment and from the Seasat altimeter. Marked attenuation of the waves is observed, the rate being consistent with existing theories of bottom friction and wave breaking decay. In addition, there is a significant broadening of the spectrum during propagation across reefs. Three-dimensional effects, such as refraction and defraction, can also lead to substantial wave height reduction for significant distances adjacent to coral reefs. As a result, a matrix of such reefs provides significantly more wave attenuation than may initially be expected.

  11. Can biological invasions save Caribbean coral reefs?

    PubMed

    Bellwood, David Roy; Robert Goatley, Christopher Harry

    2017-01-09

    It is widely accepted that coral reefs are in decline globally, due to climate change as well as more direct human impacts such as poor water quality and overharvesting [1-3]. Biological invasions are also seen as a major threat [4-6]; however, they may not all be negative. An invasion of Red Sea rabbitfishes is disrupting Mediterranean ecosystems by removing macro-algae - meanwhile, in contrast, the Caribbean is suffering from excess macro-algal growth. We suggest that an invasion of the Caribbean by rabbitfishes may prove beneficial, and that the future of Caribbean coral reefs may depend upon a rabbitfish invasion.

  12. The Great Barrier Reef Ocean Observing System Mooring array: Monitoring the Western Boundary Currents of the Coral Sea and Impacts on the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Steinberg, C. R.; McAllister, F.; Brinkman, B. W.; Pitcher, C.; Luetchford, J.; Rigby, P.

    2009-05-01

    Since 1987 Great Barrier Reef weather and water temperature observations have been transmitted in near real time using HF radio from pontoons or towers on coral reefs by AIMS. In contrast oceanographic measurements have however been restricted to loggers serviced at quarterly to half yearly downloads. The Great Barrier Reef Ocean Observing System (GBROOS) is a regional node of the Integrated Marine Observing System (IMOS). IMOS is an Australian Government initiative established under the National Collaborative Research Infrastructure Strategy and has been supported by Queensland Government since 2006. GBROOS comprises real time observations from weather stations, oceanographic moorings, underway ship observations, ocean surface radar, satellite image reception and reef based sensor networks. This paper focuses on an array of in-line moorings that have been deployed along the outer Great Barrier Reef in order to monitor the Western Boundary currents of the Coral Sea. The Westward flowing Southern Equatorial Current bifurcates into the poleward flowing East Australian Current and the equatorward North Queensland Current. The 4 mooring pairs consist of a continental slope mooring, nominally in 200m of water and one on the outer continental shelf within the GBR matrix in depths of 30 to 70m. The array is designed to detect any changes in circulation, temperature response, mixed layer depth and ocean-shelf interactions. A review of likely impacts of climate change on the physical oceanography of the GBR is providing a basis upon which to explore what processes may be affected by climate change. Sample data and results from the initial year of observations will be presented.

  13. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 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...

  14. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true 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...

  15. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 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...

  16. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2010 CFR

    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...

  17. Coral colonisation of a shallow reef flat in response to rising sea level: quantification from 35 years of remote sensing data at Heron Island, Australia

    NASA Astrophysics Data System (ADS)

    Scopélitis, J.; Andréfouët, S.; Phinn, S.; Done, T.; Chabanet, P.

    2011-12-01

    Observations made on Heron Island reef flat during the 1970s-1990s highlighted the importance of rapid change in hydrodynamics and accommodation space for coral development. Between the 1940s and the 1990s, the minimum reef-flat top water level varied by some tens of centimetres, successively down then up, in rapid response to local engineering works. Coral growth followed sea-level variations and was quantified here for several coral communities using horizontal two-dimensional above water remotely sensed observations. This required seven high spatial resolution aerial photographs and Quickbird satellite images spanning 35 years: 1972, 1979, 1990, 1992, 2002, 2006 and 2007. The coral growth dynamics followed four regimes corresponding to artificially induced changes in sea levels: 1972-1979 (lowest growth rate): no detectable coral development, due to high tidal currents and minimum mean low-tide water level; 1979-1991 (higher growth rate): horizontal coral development promoted by calmer hydrodynamic conditions; 1991-2001(lower growth rate): vertical coral development, induced by increased local sea level by ~12 cm due to construction of new bund walls; 2001-2007 (highest growth rate): horizontal coral development after that vertical growth had become limited by sea level. This unique time-series displays a succession of ecological stage comprising a `catch-up' dynamic in response to a rapid local sea-level rise in spite of the occurrences of the most severe bleaching events on record (1998, 2002) and the decreasing calcification rates reported in massive corals in the northern part of the Great Barrier Reef.

  18. Predictions of turbidity due to enhanced sediment resuspension resulting from sea-level rise on a fringing Coral Reef: Evidence from Molokai, Hawaii

    USGS Publications Warehouse

    Ogston, A.S.; Field, M.E.

    2010-01-01

    Accelerating sea-level rise associated with global climate change will affect sedimentary processes on coral reefs and other shoreline environments by increasing energy and sediment resuspension. On reefs, sedimentation is known to increase coral stress and bleaching as particles that settle on coral surfaces interfere with photosynthesis and feeding, and turbidity induced by suspended sediment reduces incident light levels. Using relationships developed from observations of wave orbital velocity, water-surface elevation, and suspended-sediment concentration on a fringing reef flat of Molokai, Hawaii, predictions of the average daily maximum in suspended-sediment concentration increase from ~11 mg/l to ~20 mg/l with 20 cm sea-level rise. The duration of time concentrations exceeds 10 mg/l increases from 9 to 37. An evaluation of the reduction of wave energy flux through breaking and frictional dissipation across the reef flat shows an increase of ~80 relative to the present will potentially reach the shoreline as sea level increases by 20 cm. Where the shoreline exists on low, flat terrain, the increased energy could cause significant erosion of the shoreline. Considering the sediment budget, the sediment flux is predicted to increase and removal of fine-grained sediment may be expedited on some fringing reefs, and sediment in storage on the inner reef could ultimately be reduced. However, increased shoreline erosion may add sediment and offset removal from the reef flat. The shifts in sediment availability and transport that will occur as result of a modest increase in sea level have wide application to fringing coral reefs elsewhere, as well as other shoreline environments. ?? 2010 the Coastal Education & Research Foundation (CERF).

  19. NOAA Coral Reef Watch: Decision Support Tools for Coral Reef Managers

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    A multitude of natural and anthropogenic stressors exert substantial influence on coral reef ecosystems and contribute to bleaching events, slower coral growth, infectious disease outbreaks, and mortality. Satellite-based observations can monitor, at a global scale, environmental conditions that influence both short-term and long-term coral reef ecosystem health. From research to operations, NOAA Coral Reef Watch (CRW) incorporates paleoclimatic, in situ, and satellite-based biogeophysical data to provide near-real-time and forecast information and tools to help managers, researchers, and other stakeholders interpret coral health and stress. CRW has developed an operational, near-real-time product suite that includes sea surface temperature (SST), SST time series data, SST anomaly charts, coral bleaching HotSpots, and Degree Heating Weeks (DHW). Bi-weekly global SST analyses are based on operational nighttime-only SST at 50-km resolution. CRW is working to develop high-resolution products to better address thermal stress on finer scales and is applying climate models to develop seasonal outlooks of coral bleaching. Automated Satellite Bleaching Alerts (SBAs), available at Virtual Stations worldwide, provide the only global early-warning system to notify managers of changing reef environmental conditions. Currently, CRW is collaborating with numerous domestic and international partners to develop new tools to address ocean acidification, infectious diseases of corals, combining light and temperature to detect coral photosystem stress, and other parameters.

  20. CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

    DTIC Science & Technology

    1999-09-30

    CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field Charles S. Yentsch Bigelow Laboratory for Ocean Sciences 180 McKown Point W...REPORT TYPE 3. DATES COVERED 00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine...affecting the decline of coral reefs is change in water transparency driven by anthropogenic rather than natural processes. Corals are known to

  1. Confronting the coral reef crisis

    NASA Astrophysics Data System (ADS)

    Bellwood, D. R.; Hughes, T. P.; Folke, C.; Nyström, M.

    2004-06-01

    The worldwide decline of coral reefs calls for an urgent reassessment of current management practices. Confronting large-scale crises requires a major scaling-up of management efforts based on an improved understanding of the ecological processes that underlie reef resilience. Managing for improved resilience, incorporating the role of human activity in shaping ecosystems, provides a basis for coping with uncertainty, future changes and ecological surprises. Here we review the ecological roles of critical functional groups (for both corals and reef fishes) that are fundamental to understanding resilience and avoiding phase shifts from coral dominance to less desirable, degraded ecosystems. We identify striking biogeographic differences in the species richness and composition of functional groups, which highlight the vulnerability of Caribbean reef ecosystems. These findings have profound implications for restoration of degraded reefs, management of fisheries, and the focus on marine protected areas and biodiversity hotspots as priorities for conservation.

  2. Cyphastreakausti sp. n. (Cnidaria, Anthozoa, Scleractinia), a new species of reef coral from the Red Sea.

    PubMed

    Bouwmeester, Jessica; Benzoni, Francesca; Baird, Andrew H; Berumen, Michael L

    2015-01-01

    A new scleractinian coral species, Cyphastreakausti sp. n., is described from 13 specimens from the Red Sea. It is characterised by the presence of eight primary septa, unlike the other species of the genus, which have six, ten or 12 primary septa. The new species has morphological affinities with Cyphastreamicrophthalma, from which it can be distinguished by the lower number of septa (on average eight instead of ten), and smaller calices and corallites. This species was observed in the northern and central Red Sea and appears to be absent from the southern Red Sea.

  3. The continuing decline of coral reefs in Bahrain.

    PubMed

    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.

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

    PubMed

    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.

  5. Year-Long Monitoring of Physico-Chemical and Biological Variables Provide a Comparative Baseline of Coral Reef Functioning in the Central Red Sea

    PubMed Central

    Roik, Anna; Röthig, Till; Roder, Cornelia; Ziegler, Maren; Kremb, Stephan G.

    2016-01-01

    Coral reefs in the central Red Sea are sparsely studied and in situ data on physico-chemical and key biotic variables that provide an important comparative baseline are missing. To address this gap, we simultaneously monitored three reefs along a cross-shelf gradient for an entire year over four seasons, collecting data on currents, temperature, salinity, dissolved oxygen (DO), chlorophyll-a, turbidity, inorganic nutrients, sedimentation, bacterial communities of reef water, and bacterial and algal composition of epilithic biofilms. Summer temperature (29–33°C) and salinity (39 PSU) exceeded average global maxima for coral reefs, whereas DO concentration was low (2–4 mg L-1). While temperature and salinity differences were most pronounced between seasons, DO, chlorophyll-a, turbidity, and sedimentation varied most between reefs. Similarly, biotic communities were highly dynamic between reefs and seasons. Differences in bacterial biofilms were driven by four abundant families: Rhodobacteraceae, Flavobacteriaceae, Flammeovirgaceae, and Pseudanabaenaceae. In algal biofilms, green crusts, brown crusts, and crustose coralline algae were most abundant and accounted for most of the variability of the communities. Higher bacterial diversity of biofilms coincided with increased algal cover during spring and summer. By employing multivariate matching, we identified temperature, salinity, DO, and chlorophyll-a as the main contributing physico-chemical drivers of biotic community structures. These parameters are forecast to change most with the progression of ocean warming and increased nutrient input, which suggests an effect on the recruitment of Red Sea benthic communities as a result of climate change and anthropogenic influence. In conclusion, our study provides insight into coral reef functioning in the Red Sea and a comparative baseline to support coral reef studies in the region. PMID:27828965

  6. Year-Long Monitoring of Physico-Chemical and Biological Variables Provide a Comparative Baseline of Coral Reef Functioning in the Central Red Sea.

    PubMed

    Roik, Anna; Röthig, Till; Roder, Cornelia; Ziegler, Maren; Kremb, Stephan G; Voolstra, Christian R

    2016-01-01

    Coral reefs in the central Red Sea are sparsely studied and in situ data on physico-chemical and key biotic variables that provide an important comparative baseline are missing. To address this gap, we simultaneously monitored three reefs along a cross-shelf gradient for an entire year over four seasons, collecting data on currents, temperature, salinity, dissolved oxygen (DO), chlorophyll-a, turbidity, inorganic nutrients, sedimentation, bacterial communities of reef water, and bacterial and algal composition of epilithic biofilms. Summer temperature (29-33°C) and salinity (39 PSU) exceeded average global maxima for coral reefs, whereas DO concentration was low (2-4 mg L-1). While temperature and salinity differences were most pronounced between seasons, DO, chlorophyll-a, turbidity, and sedimentation varied most between reefs. Similarly, biotic communities were highly dynamic between reefs and seasons. Differences in bacterial biofilms were driven by four abundant families: Rhodobacteraceae, Flavobacteriaceae, Flammeovirgaceae, and Pseudanabaenaceae. In algal biofilms, green crusts, brown crusts, and crustose coralline algae were most abundant and accounted for most of the variability of the communities. Higher bacterial diversity of biofilms coincided with increased algal cover during spring and summer. By employing multivariate matching, we identified temperature, salinity, DO, and chlorophyll-a as the main contributing physico-chemical drivers of biotic community structures. These parameters are forecast to change most with the progression of ocean warming and increased nutrient input, which suggests an effect on the recruitment of Red Sea benthic communities as a result of climate change and anthropogenic influence. In conclusion, our study provides insight into coral reef functioning in the Red Sea and a comparative baseline to support coral reef studies in the region.

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

    PubMed

    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.

  8. CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

    DTIC Science & Technology

    2001-09-30

    CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field Dr. Charles S. Yentsch Bigelow Laboratory McKown Point Road West...2001 to 00-00-2001 4. TITLE AND SUBTITLE CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field 5a. CONTRACT NUMBER 5b. GRANT

  9. Coral reefs. Limited scope for latitudinal extension of reef corals.

    PubMed

    Muir, Paul R; Wallace, Carden C; Done, Terence; Aguirre, J David

    2015-06-05

    An analysis of present-day global depth distributions of reef-building corals and underlying environmental drivers contradicts a commonly held belief that ocean warming will promote tropical coral expansion into temperate latitudes. Using a global data set of a major group of reef corals, we found that corals were confined to shallower depths at higher latitudes (up to 0.6 meters of predicted shallowing per additional degree of latitude). Latitudinal attenuation of the most important driver of this phenomenon-the dose of photosynthetically available radiation over winter-would severely constrain latitudinal coral range extension in response to ocean warming. Latitudinal gradients in species richness for the group also suggest that higher winter irradiance at depth in low latitudes allowed a deep-water fauna that was not viable at higher latitudes.

  10. Decline in sea snake abundance on a protected coral reef system in the New Caledonian Lagoon

    NASA Astrophysics Data System (ADS)

    Goiran, C.; Shine, R.

    2013-03-01

    Monitoring results from a small reef (Ile aux Canards) near Noumea in the New Caledonian Lagoon reveal that numbers of turtle-headed sea snakes ( Emydocephalus annulatus) have been in consistent decline over a 9-year period, with average daily counts of snakes decreasing from >6 to <2 over this period. Causal factors for the decline are unclear, because the site is a protected area used only for tourism. Our results suggest that wildlife management authorities should carefully monitor sea snake populations to check whether the declines now documented for New Caledonia and in nearby Australian waters also occur around the islands of the Indo-Pacific.

  11. CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

    DTIC Science & Technology

    2002-09-30

    CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field Dr. Charles S. Yentsch Bigelow Laboratory McKown Point Road West...TYPE 3. DATES COVERED 00-00-2002 to 00-00-2002 4. TITLE AND SUBTITLE CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field...remote assessment of salinity and ocean color in Florida Bay. In: The Everglades, Florida Bay and Coral Reefs of the Florida Keys: An Ecosystem

  12. Coral mucus fuels the sponge loop in warm- and cold-water coral reef ecosystems.

    PubMed

    Rix, Laura; de Goeij, Jasper M; Mueller, Christina E; Struck, Ulrich; Middelburg, Jack J; van Duyl, Fleur C; Al-Horani, Fuad A; Wild, Christian; Naumann, Malik S; van Oevelen, Dick

    2016-01-07

    Shallow warm-water and deep-sea cold-water corals engineer the coral reef framework and fertilize reef communities by releasing coral mucus, a source of reef dissolved organic matter (DOM). By transforming DOM into particulate detritus, sponges play a key role in transferring the energy and nutrients in DOM to higher trophic levels on Caribbean reefs via the so-called sponge loop. Coral mucus may be a major DOM source for the sponge loop, but mucus uptake by sponges has not been demonstrated. Here we used laboratory stable isotope tracer experiments to show the transfer of coral mucus into the bulk tissue and phospholipid fatty acids of the warm-water sponge Mycale fistulifera and cold-water sponge Hymedesmia coriacea, demonstrating a direct trophic link between corals and reef sponges. Furthermore, 21-40% of the mucus carbon and 32-39% of the nitrogen assimilated by the sponges was subsequently released as detritus, confirming a sponge loop on Red Sea warm-water and north Atlantic cold-water coral reefs. The presence of a sponge loop in two vastly different reef environments suggests it is a ubiquitous feature of reef ecosystems contributing to the high biogeochemical cycling that may enable coral reefs to thrive in nutrient-limited (warm-water) and energy-limited (cold-water) environments.

  13. Influence of environmental gradients on C and N stable isotope ratios in coral reef biota of the Red Sea, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Kürten, Benjamin; Al-Aidaroos, Ali M.; Struck, Ulrich; Khomayis, Hisham Sulaiman; Gharbawi, Waleed Yousef; Sommer, Ulrich

    2014-01-01

    The Red Sea features a natural environmental gradient characterized by increasing water temperature, nutrient and chlorophyll a concentrations from North to South. The aim of this study was to assess the relationships between ecohydrography, particulate organic matter (POM) and coral reef biota that are poorly understood by means of carbon (δ13C) and nitrogen (δ15N) stable isotopes. Herbivorous, planktivorous and carnivorous fishes, zooplankton, soft corals (Alcyonidae), and bivalves (Tridacna squamosa) were a priori defined as biota guilds. Environmental samples (nutrients, chlorophyll a), oceanographic data (salinity, temperature), POM and biota were collected at eight coral reefs between 28°31‧ N and 16°31‧ N. Isotopic niches of guilds separated in δ13C and δ15N isotopic niche spaces and were significantly correlated with environmental factors at latitudinal scale. Dietary end member contributions were estimated using the Bayesian isotope mixing model SIAR. POM and zooplankton 15N enrichment suggested influences by urban run-off in the industrialized central region of the Red Sea. Both δ15N and their relative trophic positions (RTPs) tend to increase southwards, but urban runoff offsets the natural environmental gradient in the central region of the Red Sea toward higher δ15N and RTPs. The present study reveals that consumer δ13C and δ15N in Red Sea coral reefs are influenced primarily by the latitudinal environmental gradient and localized urban runoff. This study illustrates the importance of ecohydrography when interpreting trophic relationships from stable isotopes in Red Sea coral reefs.

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

    PubMed Central

    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.

    2016-01-01

    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. PMID:27152330

  15. Coral recruitment to the reefs of Eilat, Red Sea: temporal and spatial variation, and possible effects of anthropogenic disturbances.

    PubMed

    Abelson, Avigdor; Olinky, Ronen; Gaines, Steve

    2005-05-01

    The accelerating deterioration of the coral reefs of Eilat has raised debate over the exact causes and how they affect the reefs. The hypothesis of the present study was that a low recruitment rate of reef-building coral species may play an important role in the decline of the Eilat reefs. Our goal was to assess spatial and temporal recruitment patterns in Eilat, focusing on examining the possible impact of human activities. The results of coral recruitment to 10 series of ceramic tiles on metal racks, revealed very low overall recruitment relative to other geographical regions. In addition, we found that recruitment rates and recruit survival were lowest at sites closest to the major eutrophication sources in Eilat. The low recruitment rates may be chronically too low to compensate for the elevated coral mortality rates of recent years. The significant differences between the present study and a similar study carried out during the same period using a different method, emphasize the crucial need for a standardized method for recruitment assessment in coral reefs worldwide.

  16. Forest conservation delivers highly variable coral reef conservation outcomes.

    PubMed

    Klein, Carissa J; Jupiter, Stacy D; Selig, Elizabeth R; Watts, Matthew E; Halpern, Benjamin S; Kamal, Muhammad; Roelfsema, Chris; Possingham, Hugh P

    2012-06-01

    Coral reefs are threatened by human activities on both the land (e.g., deforestation) and the sea (e.g., overfishing). Most conservation planning for coral reefs focuses on removing threats in the sea, neglecting management actions on the land. A more integrated approach to coral reef conservation, inclusive of land-sea connections, requires an understanding of how and where terrestrial conservation actions influence reefs. We address this by developing a land-sea planning approach to inform fine-scale spatial management decisions and test it in Fiji. Our aim is to determine where the protection of forest can deliver the greatest return on investment for coral reef ecosystems. To assess the benefits of conservation to coral reefs, we estimate their relative condition as influenced by watershed-based pollution and fishing. We calculate the cost-effectiveness of protecting forest and find that investments deliver rapidly diminishing returns for improvements to relative reef condition. For example, protecting 2% of forest in one area is almost 500 times more beneficial than protecting 2% in another area, making prioritization essential. For the scenarios evaluated, relative coral reef condition could be improved by 8-58% if all remnant forest in Fiji were protected rather than deforested. Finally, we determine the priority of each coral reef for implementing a marine protected area when all remnant forest is protected for conservation. The general results will support decisions made by the Fiji Protected Area Committee as they establish a national protected area network that aims to protect 20% of the land and 30% of the inshore waters by 2020. Although challenges remain, we can inform conservation decisions around the globe by tackling the complex issues relevant to integrated land-sea planning.

  17. Ecology of the south Florida coral reefs: a community profile

    SciTech Connect

    Jaap, W.C.

    1984-08-01

    An overview of coral reef research in southern Florida is provided as a prelude to a genuine description of the coral reef ecosystem in the Florida Keys and surrounding environments. Coral reef community types, reef benthos, plankton and reef fish are given specific treatment. Coral reef ecology and management are described. 27 figs., 31 tabs.

  18. Spatial dynamics of benthic competition on coral reefs.

    PubMed

    Sandin, Stuart A; McNamara, Dylan E

    2012-04-01

    The community structure of sedentary organisms is largely controlled by the outcome of direct competition for space. Understanding factors defining competitive outcomes among neighbors is thus critical for predicting large-scale changes, such as transitions to alternate states within coral reefs. Using a spatially explicit model, we explored the importance of variation in two spatial properties in benthic dynamics on coral reefs: (1) patterns of herbivory are spatially distinct between fishes and sea urchins and (2) there is wide variation in the areal extent into which different coral species can expand. We reveal that the size-specific, competitive asymmetry of corals versus fleshy algae highlights the significance of spatial patterning of herbivory and of coral growth. Spatial dynamics that alter the demographic importance of coral recruitment and maturation have profound effects on the emergent structure of the reef benthic community. Spatially constrained herbivory (as by sea urchins) is more effective than spatially unconstrained herbivory (as by many fish) at opening space for the time needed for corals to settle and to recruit to the adult population. Further, spatially unconstrained coral growth (as by many branching coral species) reduces the number of recruitment events needed to fill a habitat with coral relative to more spatially constrained growth (as by many massive species). Our model predicts that widespread mortality of branching corals (e.g., Acropora spp) and herbivorous sea urchins (particularly Diadema antillarum) in the Caribbean has greatly reduced the potential for restoration across the region.

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

    PubMed

    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.

  20. Quantifying Coral Reef Ecosystem Services

    EPA Science Inventory

    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...

  1. Physical and biological controls on the carbonate chemistry of coral reef waters: effects of metabolism, wave forcing, sea level, and geomorphology.

    PubMed

    Falter, James L; Lowe, Ryan J; Zhang, Zhenlin; McCulloch, Malcolm

    2013-01-01

    We present a three-dimensional hydrodynamic-biogeochemical model of a wave-driven coral-reef lagoon system using the circulation model ROMS (Regional Ocean Modeling System) coupled with the wave transformation model SWAN (Simulating WAves Nearshore). Simulations were used to explore the sensitivity of water column carbonate chemistry across the reef system to variations in benthic reef metabolism, wave forcing, sea level, and system geomorphology. Our results show that changes in reef-water carbonate chemistry depend primarily on the ratio of benthic metabolism to the square root of the onshore wave energy flux as well as on the length and depth of the reef flat; however, they are only weakly dependent on channel geometry and the total frictional resistance of the reef system. Diurnal variations in pCO(2), pH, and aragonite saturation state (Ω(ar)) are primarily dependent on changes in net production and are relatively insensitive to changes in net calcification; however, net changes in pCO(2), pH, and Ω(ar) are more strongly influenced by net calcification when averaged over 24 hours. We also demonstrate that a relatively simple one-dimensional analytical model can provide a good description of the functional dependence of reef-water carbonate chemistry on benthic metabolism, wave forcing, sea level, reef flat morphology, and total system frictional resistance. Importantly, our results indicate that any long-term (weeks to months) net offsets in reef-water pCO(2) relative to offshore values should be modest for reef systems with narrow and/or deep lagoons. Thus, the long-term evolution of water column pCO(2) in many reef environments remains intimately connected to the regional-scale oceanography of offshore waters and hence directly influenced by rapid anthropogenically driven increases in pCO(2).

  2. Physical and Biological Controls on the Carbonate Chemistry of Coral Reef Waters: Effects of Metabolism, Wave Forcing, Sea Level, and Geomorphology

    PubMed Central

    Falter, James L.; Lowe, Ryan J.; Zhang, Zhenlin; McCulloch, Malcolm

    2013-01-01

    We present a three-dimensional hydrodynamic-biogeochemical model of a wave-driven coral-reef lagoon system using the circulation model ROMS (Regional Ocean Modeling System) coupled with the wave transformation model SWAN (Simulating WAves Nearshore). Simulations were used to explore the sensitivity of water column carbonate chemistry across the reef system to variations in benthic reef metabolism, wave forcing, sea level, and system geomorphology. Our results show that changes in reef-water carbonate chemistry depend primarily on the ratio of benthic metabolism to the square root of the onshore wave energy flux as well as on the length and depth of the reef flat; however, they are only weakly dependent on channel geometry and the total frictional resistance of the reef system. Diurnal variations in pCO2, pH, and aragonite saturation state (Ωar) are primarily dependent on changes in net production and are relatively insensitive to changes in net calcification; however, net changes in pCO2, pH, and Ωar are more strongly influenced by net calcification when averaged over 24 hours. We also demonstrate that a relatively simple one-dimensional analytical model can provide a good description of the functional dependence of reef-water carbonate chemistry on benthic metabolism, wave forcing, sea level, reef flat morphology, and total system frictional resistance. Importantly, our results indicate that any long-term (weeks to months) net offsets in reef-water pCO2 relative to offshore values should be modest for reef systems with narrow and/or deep lagoons. Thus, the long-term evolution of water column pCO2 in many reef environments remains intimately connected to the regional-scale oceanography of offshore waters and hence directly influenced by rapid anthropogenically driven increases in pCO2. PMID:23326411

  3. Open system U-series ages of corals from a subsiding reef in New Caledonia: Implications for sea level changes, and subsidence rate

    NASA Astrophysics Data System (ADS)

    Frank, N.; Turpin, L.; Cabioch, G.; Blamart, D.; Tressens-Fedou, M.; Colin, C.; Jean-Baptiste, P.

    2006-09-01

    On the Amédée islet, 4 drill cores were recovered from the barrier reef of Western New Caledonia. The coral reef is slowly subsiding and is thus percolated by sea water during sea level highstands. The cores sample a ˜ 10 m thick Holocene reef overlying a 24 m thick reef of marine isotope stage (MIS) 5.5, which in turn overlies older reef material from MIS 7.5 and beyond. ( 234U/ 238U) and ( 230Th/ 238U) ratios and 232Th were determined by thermal ionization mass spectrometry on aragonitic coral samples that were carefully investigated using X-ray diffraction and scanning electron microscopy. The petrographic study shows an increasing coral weathering with growing coral age that causes different degree of U-series open system behavior and 232Th accumulation. Holocene corals exhibit a small degree of early diagenesis and yield 230Th/ 238U ages according to the Holocene sea level rise from ˜ 8200 years to 5000 years BP. Corals from the last Interglacial section have experienced more frequent replacement of aragonite fibers and minor dissolution, and U-series open system behavior is evident. To estimate the impact of recoil processes and alteration on the U-series system two models by Villemant and Feuillet [B. Villemant, N. Feuillet, Dating open systems by the 238U- 234U- 230Th method: application to Quaternary reef terraces, Earth and Planetary Science Letters 210(2003) 105-118.] and Thompson et al. [W. G. Thompson, M. W. Spiegelman, S. L. Goldstein, R. C. Speed, An open-system model for U-series age determinations of fossil corals, Earth and Planetary Science Letters 210(2003) 365-381.] have been tested. These models yield identical ages within uncertainty, which are in agreement to the sea level history of the past 250,000 years, as long as physico-chemical alteration and re-crystallization is small. Consequently, we were able to estimate the subsidence rate from the subsidence observed between the end of MIS 5.5 and the early Holocene, which is ˜ 0.16 ± 0

  4. New tool to manage coral reefs

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    The National Oceanic and Atmospheric Administration is making available a new tool for coral reef managers to monitor the cumulative thermal stress of several coral reefs around the world, including the Great Barrier Reef, and reefs by the Galapagos Islands, the agency announced on 25 February.The agency's "Degree Heating Weeks" product uses satellite-derived information to allow continuous monitoring of the extent and acuteness of thermal stress, which are key predictors of coral bleaching, and which contribute to coral reef degradation.

  5. 1997-98: Unprecedented thermal stress to coral reefs?

    NASA Astrophysics Data System (ADS)

    Lough, J. M.

    2000-12-01

    Mass bleaching is a stress response of corals subjected to warmer-than-normal seawater temperatures during the warm season. During 1997-98 there were unprecedented numbers of reports of bleaching on many of the world's coral reefs. Observational evidence suggests an increase in frequency of mass coral bleaching events since the late 1970s. Two indices of warm season sea surface temperatures (SSTs; SST maximum anomaly and degree-months) are presented for 47 reef sites where bleaching occurred during 1997-98. The level of thermal stress at the vast majority of these coral reef sites during 1997-98 was unmatched in the period 1903-99. Warm season SSTs at these coral reef sites have significantly warmed over this period and the frequency of warm season SST extremes has increased since the late 1970s. Continued warming of tropical SSTs, as is likely due to the enhanced greenhouse effect, will increase the level of thermal stress to coral reefs. Increased frequency of bleaching events will reduce corals' capacity to recover and may significantly alter the make-up of present day coral reef ecosystems.

  6. Air-sea energy exchanges measured by eddy covariance during a localised coral bleaching event, Heron Reef, Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    MacKellar, Mellissa C.; McGowan, Hamish A.

    2010-12-01

    Despite the widely claimed association between climate change and coral bleaching, a paucity of data exists relating to exchanges of heat, moisture and momentum between the atmosphere and the reef-water surface. We present in situ measurements of reef-water-air energy exchanges made using the eddy covariance method during a summer coral bleaching event at Heron Reef, Australia. Under settled, cloud-free conditions and light winds, daily net radiation exceeded 800 W m-2, with up to 95% of the net radiation during the morning partitioned into heating the water column, substrate and benthic cover including corals. Heating was exacerbated by a mid-afternoon low tide when shallow reef flat water reached 34°C and near-bottom temperatures 33°C, exceeding the thermal tolerance of corals, causing bleaching. Results suggest that local to synoptic scale meteorology, particularly clear skies, solar heating, light winds and the timing of low tide were the primary controls on coral bleaching.

  7. 75 FR 48934 - Coral Reef Conservation Program Implementation Guidelines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-12

    ... National Oceanic and Atmospheric Administration RIN 0648-ZC19 Coral Reef Conservation Program... Implementation Guidelines for the Coral Reef Conservation Program. SUMMARY: This document provides NOAA's revised Grant Program Implementation Guidelines (Guidelines) for the Coral Reef Conservation Program (CRCP...

  8. Detecting ecological change on coral reefs

    NASA Astrophysics Data System (ADS)

    Dustan, P.

    2011-12-01

    Remote sensing offers the potential to observe the response of coral reef ecosystems to environmental perturbations on a geographical scale not previously accessible. However, coral reef environments are optically, spatially, and temporally complex habitats which all present significant challenges for extracting meaningful information. Virtually every member of the reef community possesses some degree of photosynthetic capability. The community thus generates a matrix of fine scale features with bio-optical signatures that blend as the scale of observation increases. Furthermore, to have any validity, the remotely sensed signal must be "calibrated" to the bio-optics of the reef, a difficult and resource intensive process due to a convergence of photosynthetic light harvesting by green, red, and brown algal pigment systems. To make matters more complex, reefs are overlain by a seawater skin with its own set of hydrological optical challenges. Rather than concentrating on classification, my research has attempted to track change by following the variation in geo-referenced pixel brightness over time with a technique termed temporal texture. Environmental periodicities impart a phenology to the variation in brightness and departures from the norm are easily detected as statistical outliers. This opens the door to using current orbiting technology to efficiently examine large areas of sea for change. If hot spots are detected, higher resolution sensors and field studies can be focused as resources permit. While this technique does not identify the type of change, it is sensitive, simple to compute, easy to automate and grounded in ecological niche theory

  9. Coral reef ecosystem decline: changing dynamics of coral reef carbonate production and implications for reef growth potential

    NASA Astrophysics Data System (ADS)

    Perry, Chris

    2016-04-01

    , comparable with estimates under pre-human disturbance conditions, and are reflected in high reef growth rates (4.2 mm yr-1). These reefs thus 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. However, their positive growth potential is strongly tied to the persistence of several key coral species, and thus the frequency and magnitude of future disturbance events will be key determinants of near-future reef growth.

  10. From Corals to Canyons: The Great Barrier Reef Margin

    NASA Astrophysics Data System (ADS)

    Webster, Jody M.; Beaman, Robin J.; Bridge, Thomas; Davies, Peter J.; Byrne, Maria; Williams, Stefan; Manning, Phil; Pizarro, Oscar; Thornborough, Kate; Woolsey, Erika; Thomas, Alex; Tudhope, Sandy

    2008-06-01

    The significance of submerged fossil coral reefs as important archives of abrupt global sea level rise and climate change has been confirmed by investigations in the Caribbean [Fairbanks, 1989] and the Indo-Pacific (see Montaggioni [2005] for a summary) and by recent Integrated Ocean Drilling Program (IODP) activities in Tahiti [Camoin et al., 2007]. Similar submerged (40-130 meters) reef structures are preserved along the margin of the Great Barrier Reef (GBR), but they have not yet been systematically studied.

  11. Coral reef degradation and metabolic performance of the scleractinian coral Porites lutea under anthropogenic impact along the NE coast of Hainan Island, South China Sea

    NASA Astrophysics Data System (ADS)

    Roder, Cornelia; Wu, Zhongjie; Richter, Claudio; Zhang, Jing

    2013-04-01

    Hainan's coast provides favorable climatic, geochemical and biogeographic conditions for the development of extensive coral reefs in China. Observations in five reefs along the NE coast of Hainan showed, however, that the overall density of mobile macrofauna is low and key functional groups such as browsing, scraping or excavating herbivore fish are missing altogether. Coral diseases, partial mortality or tissue degradation are abundant and growth of macroalgal space competitors extensive. Signs of eutrophication, siltation and destructive fishing practices are evident resulting in a strongly altered environment unfavorable for coral recruitment success and survival. Acclimation to the anthropogenically altered conditions in the massive coral Porites lutea occurs at the cost of a decreased photosynthesis: respiration ratio reducing the regenerative capacity of these key framebuilding organisms. Even though, on the organismal level, corals are able to cope with these stressful conditions, a shift is imminent on the ecosystem level from a coral reef to a macroalgae-dominated community if land-based disturbance prevails unabated.

  12. The changing dynamics of coral reef science in Arabia.

    PubMed

    Vaughan, Grace O; Burt, John A

    2016-04-30

    Six percent of the world's coral reefs occur around the Arabian Peninsula, providing a valuable ecological, economic and scientific resource for the nations bordering its shores. We provide the first region-wide assessment of the current status and historical trends in coral reef research, focusing on research in the Red Sea, Arabian Sea, and Arabian Gulf. In total, 633 regional reef publications have been produced since the 1930s, covering a wide variety of themes and taxa. Our results show a great deal of commonality in regional reef research, but also highlight important differences in research among the various seas as well as knowledge gaps that represent opportunities for future research. A regionally-integrated approach to future research is essential. There is a growing need for large-scale research to guide management of reefs and their stressors, as these operate at much larger scales than the national borders within which most research currently occurs.

  13. Pulley reef: a deep photosynthetic coral reef on the West Florida Shelf, USA

    USGS Publications Warehouse

    Culter, J.K.; Ritchie, K.B.; Earle, S.A.; Guggenheim, D.E.; Halley, R.B.; Ciembronowicz, K.T.; Hine, A.C.; Jarrett, B.D.; Locker, S.D.; Jaap, W.C.

    2006-01-01

    Pulley Reef (24°50′N, 83°40′W) lies on a submerged late Pleistocene shoreline feature that formed during a sea-level stillstand from 13.8 to 14.5 ka (Jarrett et al. 2005). The reef is currently 60–75 m deep, exhibits 10–60% coral cover, and extends over approximately 160 km2 of the sea floor. Zooxanthellate corals are primarily Agaricia lamarcki, A. fragilis, Leptoseris cucullata, and less common Madracis formosa, M. pharensis, M. decactis, Montastraea cavernosa, Porites divaricata, Scolymia cubensis and Oculina tenella. Coralline algae are comparable in abundance to stony corals. Other macroalgae include Halimeda tuna, Dictyota divaricata, Lobophora variegata, Ventricatri ventricosa, Verdigelas pelas, and Kallymenia sp. Anadyomene menziesii is abundant. The reef provides a habitat for organisms typically observed at much shallower depths, and is the deepest known photosynthetic coral reef on the North America continental shelf (Fig. 1).

  14. A novel reef coral symbiosis

    NASA Astrophysics Data System (ADS)

    Pantos, O.; Bythell, J. C.

    2010-09-01

    Reef building corals form close associations with unicellular microalgae, fungi, bacteria and archaea, some of which are symbiotic and which together form the coral holobiont. Associations with multicellular eukaryotes such as polychaete worms, bivalves and sponges are not generally considered to be symbiotic as the host responds to their presence by forming physical barriers with an active growth edge in the exoskeleton isolating the invader and, at a subcellular level, activating innate immune responses such as melanin deposition. This study describes a novel symbiosis between a newly described hydrozoan ( Zanclea margaritae sp. nov.) and the reef building coral Acropora muricata (= A. formosa), with the hydrozoan hydrorhiza ramifying throughout the coral tissues with no evidence of isolation or activation of the immune systems of the host. The hydrorhiza lacks a perisarc, which is typical of symbiotic species of this and related genera, including species that associate with other cnidarians such as octocorals. The symbiosis was observed at all sites investigated from two distant locations on the Great Barrier Reef, Australia, and appears to be host species specific, being found only in A. muricata and in none of 30 other species investigated at these sites. Not all colonies of A. muricata host the hydrozoans and both the prevalence within the coral population (mean = 66%) and density of emergent hydrozoan hydranths on the surface of the coral (mean = 4.3 cm-2, but up to 52 cm-2) vary between sites. The form of the symbiosis in terms of the mutualism-parasitism continuum is not known, although the hydrozoan possesses large stenotele nematocysts, which may be important for defence from predators and protozoan pathogens. This finding expands the known A. muricata holobiont and the association must be taken into account in future when determining the corals’ abilities to defend against predators and withstand stress.

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

    PubMed Central

    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

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

    PubMed

    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

  17. Building coral reef resilience through assisted evolution

    PubMed Central

    van Oppen, Madeleine J. H.; Oliver, James K.; Putnam, Hollie M.; Gates, Ruth D.

    2015-01-01

    The genetic enhancement of wild animals and plants for characteristics that benefit human populations has been practiced for thousands of years, resulting in impressive improvements in commercially valuable species. Despite these benefits, genetic manipulations are rarely considered for noncommercial purposes, such as conservation and restoration initiatives. Over the last century, humans have driven global climate change through industrialization and the release of increasing amounts of CO2, resulting in shifts in ocean temperature, ocean chemistry, and sea level, as well as increasing frequency of storms, all of which can profoundly impact marine ecosystems. Coral reefs are highly diverse ecosystems that have suffered massive declines in health and abundance as a result of these and other direct anthropogenic disturbances. There is great concern that the high rates, magnitudes, and complexity of environmental change are overwhelming the intrinsic capacity of corals to adapt and survive. Although it is important to address the root causes of changing climate, it is also prudent to explore the potential to augment the capacity of reef organisms to tolerate stress and to facilitate recovery after disturbances. Here, we review the risks and benefits of the improvement of natural and commercial stocks in noncoral reef systems and advocate a series of experiments to determine the feasibility of developing coral stocks with enhanced stress tolerance through the acceleration of naturally occurring processes, an approach known as (human)-assisted evolution, while at the same time initiating a public dialogue on the risks and benefits of this approach. PMID:25646461

  18. Building coral reef resilience through assisted evolution.

    PubMed

    van Oppen, Madeleine J H; Oliver, James K; Putnam, Hollie M; Gates, Ruth D

    2015-02-24

    The genetic enhancement of wild animals and plants for characteristics that benefit human populations has been practiced for thousands of years, resulting in impressive improvements in commercially valuable species. Despite these benefits, genetic manipulations are rarely considered for noncommercial purposes, such as conservation and restoration initiatives. Over the last century, humans have driven global climate change through industrialization and the release of increasing amounts of CO2, resulting in shifts in ocean temperature, ocean chemistry, and sea level, as well as increasing frequency of storms, all of which can profoundly impact marine ecosystems. Coral reefs are highly diverse ecosystems that have suffered massive declines in health and abundance as a result of these and other direct anthropogenic disturbances. There is great concern that the high rates, magnitudes, and complexity of environmental change are overwhelming the intrinsic capacity of corals to adapt and survive. Although it is important to address the root causes of changing climate, it is also prudent to explore the potential to augment the capacity of reef organisms to tolerate stress and to facilitate recovery after disturbances. Here, we review the risks and benefits of the improvement of natural and commercial stocks in noncoral reef systems and advocate a series of experiments to determine the feasibility of developing coral stocks with enhanced stress tolerance through the acceleration of naturally occurring processes, an approach known as (human)-assisted evolution, while at the same time initiating a public dialogue on the risks and benefits of this approach.

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

    PubMed Central

    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 (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

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

    PubMed

    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 (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

  1. Rapid fluctuations in flow and water-column properties in Asan Bay, Guam: implications for selective resilience of coral reefs in warming seas

    USGS Publications Warehouse

    Storlazzi, C.D.; Field, M.E.; Cheriton, O.M.; Presto, M.K.; Logan, J.B.

    2013-01-01

    Hydrodynamics and water-column properties were investigated off west-central Guam from July 2007 through January 2008. Rapid fluctuations, on time scales of 10s of min, in currents, temperature, salinity, and acoustic backscatter were observed to occur on sub-diurnal frequencies along more than 2 km of the fore reef but not at the reef crest. During periods characterized by higher sea-surface temperatures (SSTs), weaker wind forcing, smaller ocean surface waves, and greater thermal stratification, rapid decreases in temperature and concurrent rapid increases in salinity and acoustic backscatter coincided with onshore-directed near-bed currents and offshore-directed near-surface currents. During the study, these cool-water events, on average, lasted 2.3 h and decreased the water temperature 0.57 °C, increased the salinity 0.25 PSU, and were two orders of magnitude more prevalent during the summer season than the winter. During the summer season when the average satellite-derived SST anomaly was +0.63 °C, these cooling events, on average, lowered the temperature 1.14 °C along the fore reef but only 0.11 °C along the reef crest. The rapid shifts appear to be the result of internal tidal bores pumping cooler, more saline, higher-backscatter oceanic water from depths >50 m over cross-shore distances of 100 s of m into the warmer, less saline waters at depths of 20 m and shallower. Such internal bores appear to have the potential to buffer shallow coral reefs from predicted increases in SSTs by bringing cool, offshore water to shallow coral environments. These cooling internal bores may also provide additional benefits to offset stress such as supplying food to thermally stressed corals, reducing stress due to ultraviolet radiation and/or low salinity, and delivering coral larvae from deeper reefs not impacted by surface thermal stress. Thus, the presence of internal bores might be an important factor locally in the resilience of select coral reefs facing increased

  2. Coral reef bleaching at Agatti Island of Lakshadweep atolls, India

    NASA Astrophysics Data System (ADS)

    Vinoth, Ramar; Gopi, Mohan; Kumar, Thipramalai Thankappanpillai Ajith; Thangaradjou, Thirunavukarassu; Balasubramanian, Thangavel

    2012-03-01

    A survey on coral bleaching was carried out at Agatti Island of Lakshadweep from May to June 2010. Elevated sea surface temperatures (SSTs) of the region exceeded the seasonal average and delayed the onset of monsoon, which triggered widespread bleaching of corals. The Agatti reefs showed an average of 73% bleached corals with apparent bleaching-related mortality of sea anemones (87%) and giant clams (83%). The SST increased up to 34 °C with an average maximum SST of 32.5 during the study °C period between May and June 2010. Coral reefs on the southern side of the island are fully or partially exposed to sun light during low tide in contrast to the other side. This suggests that the mortality is more likely due to the low tide exposure than exclusively due to the elevated SST. Observations indicated a clear increase in coral bleaching during April 2010, at levels higher than that in normal summer.

  3. Younger Dryas sea level and meltwater pulse 1B recorded in Barbados reef crest coral Acropora palmata

    NASA Astrophysics Data System (ADS)

    Abdul, N. A.; Mortlock, R. A.; Wright, J. D.; Fairbanks, R. G.

    2016-02-01

    The Younger Dryas climate event occurred during the middle of the last deglacial cycle and is marked by an abrupt shift in the North Atlantic polar front almost to its former glacial position, trending east to west. Using high-precision and high-accuracy U-Th-dated Barbados reef crest coral, Acropora palmata, we generate a detailed sea level record from 13.9 to 9000 years before present (kyr B.P.) and reconstruct the ice volume response to the Younger Dryas cooling. From the mid-Allerød (13.9 kyr B.P.) to the end of the Younger Dryas (11.65 kyr B.P.), rates of sea level rise decreased smoothly from 20 mm yr-1 to 4 mm yr-1, culminating in a 400 year "slow stand" before accelerating into meltwater pulse 1B (MWP-1B). The MWP-1B event at Barbados is better constrained as beginning by 11.45 kyr B.P. and ending at 11.1 kyr B.P. during which time sea level rose 14 ± 2 m and rates of sea level rise reached 40 mm yr-1. We propose that MWP-1B is the direct albeit lagged response of the Northern Hemisphere ice sheets to the rapid warming marking the end of the Younger Dryas coinciding with rapid warming in the circum-North Atlantic region and the polar front shift from its zonal to meridional position 11.65 kyr B.P. As predicted by glaciological models, the ice sheet response to rapid North Atlantic warming was lagged by 400 years due to the thermal inertia of large ice sheets. The regional circum-North Atlantic Younger Dryas climate event is elevated to a global response through sea level changes, starting with the global slowdown in sea level rise during the Younger Dryas and culminating with MWP-1B. No meltwater pulses are evident at the initiation of the Younger Dryas climate event as is often speculated.

  4. Prickly business: abundance of sea urchins on breakwaters and coral reefs in Dubai.

    PubMed

    Bauman, Andrew G; Dunshea, Glenn; Feary, David A; Hoey, Andrew S

    2016-04-30

    Echinometra mathaei is a common echinoid on tropical reefs and where abundant plays an important role in the control of algal communities. Despite high prevalence of E. mathaei on southern Persian/Arabian Gulf reefs, their abundance and distribution is poorly known. Spatial and temporal patterns in population abundance were examined at 12 sites between breakwater and natural reef habitats in Dubai (UAE) every 3 months from 2008 to 2010. Within the breakwater habitat, densities were greatest at shallow wave-exposed sites, and reduced with both decreasing wave-exposure and increasing depth. Interestingly, E. mathaei were significantly more abundant on exposed breakwaters than natural reef sites, presumably due to differences in habitat structure and benthic cover. Population abundances differed seasonally, with peak abundances during summer (July-September) and lower abundances in winter (December-February). Seasonal fluctuations are likely the result of peak annual recruitment pulses coupled with increased fish predation from summer to winter.

  5. Assessing the herbivore role of the sea-urchin Echinometra viridis: Keys to determine the structure of communities in disturbed coral reefs.

    PubMed

    Sangil, Carlos; Guzman, Hector M

    2016-09-01

    Echinometra viridis previously was considered a cryptic species unable to control the development and growth of macroalgae on coral reefs. Its role as a herbivore was seen as minor compared to other grazers present on the reef. However, the present disturbed state of some reefs has highlighted the role played by this sea-urchin. Combining field data with experiments on the Caribbean coast of Panama, we demonstrate that the current community organization on disturbed coral reefs in the Mesoamerican Caribbean is largely due to the action of E. viridis. It is the most abundant sea-urchin species, together with two others (Diadema antillarum and Echinometra lucunter). Field data also indicate that the relationship between its density and the abundance of macroalgae is stronger and it is more negative in impact than those of the other two. However, the niche this urchin exploits most efficiently is confined to leeward reefs with low levels of sedimentation. Outside these habitats, their populations are not decisive in controlling macroalgal growth. Grazing experiments showed that E. viridis consumes more fresh macroalgae per day and per weight of sea-urchin, and is a more effective grazer than D. antillarum or E. lucunter. E. viridis showed food preferences for early-successional turf macroalgae (Acanthophora spicifera), avoiding the less palatable late-successional and fleshy macroalgae (Lobophora variegata, Halimeda opuntia). However, it becomes a generalist herbivore feeding on all varieties of macroalgae when resources are scarce. H. opuntia is the macroalga that most resists E. viridis activity, which may explain its wide distribution.

  6. Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages

    PubMed Central

    Waheed, Zarinah; van Mil, Harald G. J.; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W.

    2015-01-01

    The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park. PMID:26719987

  7. Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages.

    PubMed

    Waheed, Zarinah; van Mil, Harald G J; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W

    2015-01-01

    The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park.

  8. Potential for Expansion of Coral Reefs into Higher Latitudes due to Climate Change

    DTIC Science & Technology

    2003-09-01

    SEP 2003 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Potential for Expansion of Coral Reefs into Higher Latitudes due to...ANSI Std Z39-18 0-933957-31-9 P2745 Potential for Expansion of Coral Reefs into Higher Latitudes due to Climate...investigate if there have been any effects on Sea Surface Temperature (SST) at geographical margins of coral reefs . It is generally accepted that

  9. Geological Approaches to Coral Reef Ecology

    NASA Astrophysics Data System (ADS)

    Kench, Paul

    2008-09-01

    Tropical coral reef systems cover an estimated 284,300 square kilometers of the Earth's surface and are considered among the most valuable ecosystems on Earth. The reef systems are zones of high biological diversity, habitat for about one quarter of all known marine species, and important components of the global carbon cycle. In addition, they provide the physical foundation for a number of mid-ocean nation states. Coral reefs worldwide are considered to be in serious ecological decline due to anthropogenic impacts, natural stresses, and climate change. However, these gloomy projections for coral reefs are based largely on analysis of short-term changes in their ecological condition.

  10. Intrareef variations in Li/Mg and Sr/Ca sea surface temperature proxies in the Caribbean reef-building coral Siderastrea siderea

    NASA Astrophysics Data System (ADS)

    Fowell, Sara E.; Sandford, Kate; Stewart, Joseph A.; Castillo, Karl D.; Ries, Justin B.; Foster, Gavin L.

    2016-10-01

    Caribbean sea surface temperatures (SSTs) have increased at a rate of 0.2°C per decade since 1971, a rate double that of the mean global change. Recent investigations of the coral Siderastrea siderea on the Belize Mesoamerican Barrier Reef System (MBRS) have demonstrated that warming over the last 30 years has had a detrimental impact on calcification. Instrumental temperature records in this region are sparse, making it necessary to reconstruct longer SST records indirectly through geochemical temperature proxies. Here we investigate the skeletal Sr/Ca and Li/Mg ratios of S. siderea from two distinct reef zones (forereef and backreef) of the MBRS. Our field calibrations of S. siderea show that Li/Mg and Sr/Ca ratios are well correlated with temperature, although both ratios are 3 times more sensitive to temperature change in the forereef than in the backreef. These differences suggest that a secondary parameter also influences these SST proxies, highlighting the importance for site- and species-specific SST calibrations. Application of these paleothermometers to downcore samples reveals highly uncertain reconstructed temperatures in backreef coral, but well-matched reconstructed temperatures in forereef coral, both between Sr/Ca-SSTs and Li/Mg-SSTs, and in comparison to the Hadley Centre Sea Ice and Sea Surface Temperature record. Reconstructions generated from a combined Sr/Ca and Li/Mg multiproxy calibration improve the precision of these SST reconstructions. This result confirms that there are circumstances in which both Li/Mg and Sr/Ca are reliable as stand-alone and combined proxies of sea surface temperature. However, the results also highlight that high-precision, site-specific calibrations remain critical for reconstructing accurate SSTs from coral-based elemental proxies.

  11. Dynamic fragility of oceanic coral reef ecosystems

    PubMed Central

    Graham, Nicholas A. J.; Wilson, Shaun K.; Jennings, Simon; Polunin, Nicholas V. C.; Bijoux, Jude P.; Robinson, Jan

    2006-01-01

    As one of the most diverse and productive ecosystems known, and one of the first ecosystems to exhibit major climate-warming impacts (coral bleaching), coral reefs have drawn much scientific attention to what may prove to be their Achilles heel, the thermal sensitivity of reef-building corals. Here we show that climate change-driven loss of live coral, and ultimately structural complexity, in the Seychelles results in local extinctions, substantial reductions in species richness, reduced taxonomic distinctness, and a loss of species within key functional groups of reef fish. The importance of deteriorating physical structure to these patterns demonstrates the longer-term impacts of bleaching on reefs and raises questions over the potential for recovery. We suggest that isolated reef systems may be more susceptible to climate change, despite escaping many of the stressors impacting continental reefs. PMID:16709673

  12. Sewage impacts coral reefs at multiple levels of ecological organization.

    PubMed

    Reopanichkul, Pasinee; Schlacher, Thomas A; Carter, R W; Worachananant, Suchai

    2009-09-01

    Against a backdrop of rising sea temperatures and ocean acidification which pose global threats to coral reefs, excess nutrients and turbidity continue to be significant stressors at regional and local scales. Because interventions usually require local data on pollution impacts, we measured ecological responses to sewage discharges in Surin Marine Park, Thailand. Wastewater disposal significantly increased inorganic nutrients and turbidity levels, and this degradation in water quality resulted in substantial ecological shifts in the form of (i) increased macroalgal density and species richness, (ii) lower cover of hard corals, and (iii) significant declines in fish abundance. Thus, the effects of nutrient pollution and turbidity can cascade across several levels of ecological organization to change key properties of the benthos and fish on coral reefs. Maintenance or restoration of ecological reef health requires improved wastewater management and run-off control for reefs to deliver their valuable ecosystems services.

  13. Astronaut Photography of Coral Reefs

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.; Noordeloos, Marco

    2001-01-01

    Astronaut photographs of tropical coastal areas may contain information on submerged features, including coral reefs, up to depths of about 15 m in clear waters. Previous research efforts have shown that astronaut photographs can aid in estimating coral reef locations and extent on national, regional and global scales, and allow characterization of major geomorphological rim and lagoon features (Andrefouet et al. 2000, in preparation). They can be combined with traditional satellite data to help distinguish between clouds and lagoon features such as pinnacles (Andrefouet and Robinson, in review). Furthermore, astronaut photographs may provide reef scientists and managers with information on the location and extent of river plumes and sediment run off, or facilitate identification of land cover types, including mangroves (Webb et al., in press). Photographs included in the section were selected based on several criteria. The primary consideration of the editors was that the photographs represent a worldwide distribution of coral reefs, have extremely low visual interference by cloud cover, and display a spatial scale reasonable for examining reef-related features. Once photographs were selected, they were digitized from 2nd generation copies. The color and contrast were hand corrected to an approximation of natural color (required to account for spectral differences between photographs due to the color sensitivities of films used, and differences in sun angle and exposure of the photographs). None of the photographs shown here have been georeferenced to correct them to a map projection and scale. Any distortions in features due to slightly oblique look angles when the photographs were taken through spacecraft windows remain. When feasible, near vertical photographs have been rotated so that north is toward the top. An approximate scale bar and north arrow have added using distinctive features on each photograph with reference to a 1:1,000,000 scale navigation chart

  14. Sea-level history of the past two interglacial periods: New evidence from U-series dating of reef corals from south Florida

    USGS Publications Warehouse

    Muhs, D.R.; Simmons, K.R.; Schumann, R.R.; Halley, R.B.

    2011-01-01

    As a future warm-climate analog, much attention has been directed to studies of the Last Interglacial period or marine isotope substage (MIS) 5.5, which occurred ???120,000 years ago. Nevertheless, there are still uncertainties with respect to its duration, warmth and magnitude of sea-level rise. Here we present new data from tectonically stable peninsular Florida and the Florida Keys that provide estimates of the timing and magnitude of sea-level rise during the Last Interglacial period. The Last Interglacial high sea stand in south Florida is recorded by the Key Largo Limestone, a fossil reef complex, and the Miami Limestone, an oolitic marine sediment. Thirty-five new, high-precision, uranium-series ages of fossil corals from the Key Largo Limestone indicate that sea level was significantly above present for at least 9000 years during the Last Interglacial period, and possibly longer. Ooids from the Miami Limestone show open-system histories with respect to U-series dating, but show a clear linear trend toward an age of ???120 ka, correlating this unit with the Last Interglacial corals of the Key Largo Limestone. Older fossil reefs at three localities in the Florida Keys have ages of ???200 ka and probably correlate to MIS 7. These reefs imply sea level near or slightly above present during the penultimate interglacial period. Elevation measurements of both the Key Largo Limestone and the Miami Limestone indicate that local (relative) sea level was at least 6.6 m, and possibly as much as 8.3 m higher than present during the Last Interglacial period. ?? 2010.

  15. Natural bounds on herbivorous coral reef fishes

    PubMed Central

    Hoey, Andrew S.; Williams, Gareth J.; Williams, Ivor D.

    2016-01-01

    Humans are an increasingly dominant driver of Earth's biological communities, but differentiating human impacts from natural drivers of ecosystem state is crucial. Herbivorous fish play a key role in maintaining coral dominance on coral reefs, and are widely affected by human activities, principally fishing. We assess the relative importance of human and biophysical (habitat and oceanographic) drivers on the biomass of five herbivorous functional groups among 33 islands in the central and western Pacific Ocean. Human impacts were clear for some, but not all, herbivore groups. Biomass of browsers, large excavators, and of all herbivores combined declined rapidly with increasing human population density, whereas grazers, scrapers, and detritivores displayed no relationship. Sea-surface temperature had significant but opposing effects on the biomass of detritivores (positive) and browsers (negative). Similarly, the biomass of scrapers, grazers, and detritivores correlated with habitat structural complexity; however, relationships were group specific. Finally, the biomass of browsers and large excavators was related to island geomorphology, both peaking on low-lying islands and atolls. The substantial variability in herbivore populations explained by natural biophysical drivers highlights the need for locally appropriate management targets on coral reefs. PMID:27881745

  16. Natural bounds on herbivorous coral reef fishes.

    PubMed

    Heenan, Adel; Hoey, Andrew S; Williams, Gareth J; Williams, Ivor D

    2016-11-30

    Humans are an increasingly dominant driver of Earth's biological communities, but differentiating human impacts from natural drivers of ecosystem state is crucial. Herbivorous fish play a key role in maintaining coral dominance on coral reefs, and are widely affected by human activities, principally fishing. We assess the relative importance of human and biophysical (habitat and oceanographic) drivers on the biomass of five herbivorous functional groups among 33 islands in the central and western Pacific Ocean. Human impacts were clear for some, but not all, herbivore groups. Biomass of browsers, large excavators, and of all herbivores combined declined rapidly with increasing human population density, whereas grazers, scrapers, and detritivores displayed no relationship. Sea-surface temperature had significant but opposing effects on the biomass of detritivores (positive) and browsers (negative). Similarly, the biomass of scrapers, grazers, and detritivores correlated with habitat structural complexity; however, relationships were group specific. Finally, the biomass of browsers and large excavators was related to island geomorphology, both peaking on low-lying islands and atolls. The substantial variability in herbivore populations explained by natural biophysical drivers highlights the need for locally appropriate management targets on coral reefs.

  17. The 1991 1992 rapid ecological assessment of Palau's coral reefs

    NASA Astrophysics Data System (ADS)

    Maragos, J. E.; Cook, C. W.

    1995-11-01

    At the request of the Palau and US governments, a team of 30 scientists under the leadership of the Nature Conservancy completed a rapid ecological assessment (REA) of nearshore marine resources in Palau in 1992. The REA provided ecological input to Palau's ongoing master plan for economic development and identified 45 marine sites worthy of special protection. The REA relied on previous literature, 1992 aerial photography, interviews, and field observations. A combination of qualitative and quantitative techniques were used to assess stony corals, other reef invertebrates, reef and shore fishes, macroscopic algae, seagrasses, sea turtles and other marine organisms. The REA covered a variety of coral reef habitats including beaches, seagrass beds, fringing reefs, lagoons, passes, channels, reef holes, patch and pinnacle reefs, barrier reefs, atolls, submerged reefs, mangroves, and "rock" islands. Major stresses to Palau's coral reefs include sedimentation from soil erosion, overfishing, and damage from periodic storms and waves. Minor stresses include dredge-and fill activities, sewage pollution, anchor damage, tourism use, ship groundings, aquarium fish collecting, and minor crown-of-thorns ( Acanthaster) infestations.

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

    EPA Pesticide Factsheets

    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

  19. Nitrogen fixation in a coral reef community.

    PubMed

    Wiebe, W J; Johannes, R E; Webb, K L

    1975-04-18

    Algal reef flats at Enewetak Atoll, Marshall Islands, fix atmospheric nitrogen at rates comparable to those in managed agriculture. The dominant nitrogen fixer appears to be the blue-green alga Calothrix crustacea. Since this nutrient enrichment contributes to the high productivity of adjacent coral reefs and undoubtedly to atoll lagoons, it is recommended that the algal reef flats receive increased conservation priority.

  20. Photography of Coral Reefs from ISS

    NASA Technical Reports Server (NTRS)

    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.

  1. Historical decline in coral reef growth after the Panama Canal.

    PubMed

    Guzman, Hector M; Cipriani, Roberto; Jackson, Jeremy B C

    2008-07-01

    The Panama Canal is near its vessel size and tonnage handling capacity, and Panamanians have decided to expand it. The expansion of the Canal may consider the historical long-lasting impacts on marine coastal habitats particularly on sensitive coral reefs. These potential impacts were discussed during the national referendum as were other equally important issues, such as its effects on forests, watersheds, and water supply. Coral growth rates provide a direct measure of coral fitness and past environmental conditions comparable to analyses of tree rings. We examined stable isotopes, metal geochemical tracers, and growth rates on a century-long (1880-1989) chronology based on 77 cores of the dominant reef-building coral Siderastrea siderea collected near the Caribbean entrance to the canal. Our results showed a gradual decline in coral growth unrelated to changes in sea surface temperature but linked to runoff and sedimentation to coastal areas resulting from the construction and operation of the Panama Canal.

  2. Cross-shelf exchanges between the Coral Sea and the Great Barrier Reef lagoon determined from a regional-scale numerical model

    NASA Astrophysics Data System (ADS)

    Schiller, Andreas; Herzfeld, Mike; Brinkman, Richard; Rizwi, Farhan; Andrewartha, John

    2015-10-01

    Analyses of the variability in a 3.5-year run of a hydrodynamic model developed for simulating the circulation of the Great Barrier Reef (GBR) are presented. Sea-surface temperature, salinity, currents and cross-shelf transports between the GBR lagoon and the deep ocean offshore are investigated and compare well to available observations. Water mass intrusions and flushing events are critical factors in determining the health of coral reef and continental shelf ecosystems. Results from tracer release experiments provide a synoptic view of the variability of residence times within the GBR and identify critical regions of shelf-ocean exchange. One such region of significant tracer contribution to the shelf is identified in the vicinity of the Pompey Reefs in an area characterised by increased frequency of upslope transported water. Another location of enhanced flux on to the shelf exists in the region bracketing Palm Passage, where the reef matrix is very open, and provides little obstacle to cross-shelf exchange. The Palm Passage location is the origin of a northwards plume of elevated concentration. The model circulation provides a robust and useful picture of the Great Barrier Reef, rendering the model suitable for providing input to biogeochemical and sediment models to simulate, at a broad scale, the ecosystem health, water quality, transport and fate of water and waterborne material, moving through catchments and into the GBR lagoon.

  3. Avoiding coral reef functional collapse requires local and global action.

    PubMed

    Kennedy, Emma V; Perry, Chris T; Halloran, Paul R; Iglesias-Prieto, Roberto; Schönberg, Christine H L; Wisshak, Max; Form, Armin U; Carricart-Ganivet, Juan P; Fine, Maoz; Eakin, C Mark; Mumby, Peter J

    2013-05-20

    Coral reefs face multiple anthropogenic threats, from pollution and overfishing to the dual effects of greenhouse gas emissions: rising sea temperature and ocean acidification. While the abundance of coral has declined in recent decades, the implications for humanity are difficult to quantify because they depend on ecosystem function rather than the corals themselves. Most reef functions and ecosystem services are founded on the ability of reefs to maintain their three-dimensional structure through net carbonate accumulation. Coral growth only constitutes part of a reef's carbonate budget; bioerosion processes are influential in determining the balance between net structural growth and disintegration. Here, we combine ecological models with carbonate budgets and drive the dynamics of Caribbean reefs with the latest generation of climate models. Budget reconstructions using documented ecological perturbations drive shallow (6-10 m) Caribbean forereefs toward an increasingly fragile carbonate balance. We then projected carbonate budgets toward 2080 and contrasted the benefits of local conservation and global action on climate change. Local management of fisheries (specifically, no-take marine reserves) and the watershed can delay reef loss by at least a decade under "business-as-usual" rises in greenhouse gas emissions. However, local action must be combined with a low-carbon economy to prevent degradation of reef structures and associated ecosystem services.

  4. Spatial competition dynamics between reef corals under ocean acidification.

    PubMed

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

    2017-01-09

    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.

  5. Spatial competition dynamics between reef corals under ocean acidification

    NASA Astrophysics Data System (ADS)

    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.

  6. Spatial competition dynamics between reef corals under ocean acidification

    PubMed Central

    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. PMID:28067281

  7. Coral bleaching: Thermal adaptation in reef coral symbionts

    NASA Astrophysics Data System (ADS)

    Rowan, Rob

    2004-08-01

    Many corals bleach as a result of increased seawater temperature, which causes them to lose their vital symbiotic algae (Symbiodinium spp.) - unless these symbioses are able to adapt to global warming, bleaching threatens coral reefs worldwide. Here I show that some corals have adapted to higher temperatures, at least in part, by hosting specifically adapted Symbiodinium. If other coral species can host these or similar Symbiodinium taxa, they might adapt to warmer habitats relatively easily.

  8. A Modern Sr/Ca-δ18O-Sea Surface Temperature Calibration for Isopora Corals in the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Brenner, L. D.; Linsley, B. K.; Potts, D. C.

    2014-12-01

    Most coral-based paleoceanographic studies have used massive colonies of Porites or Faviidae, due to their long, continuously accreted skeletal records and sub-annual resolution, but other sub-massive corals provide an untapped resource. The genus Isopora is a dominant reef builder in some high-energy environments in the tropical western Pacific, and was a major component of cores recovered on IODP Leg 325 off the Great Barrier Reef (GBR). Despite its abundance, Isopora remains largely unexplored and hence underutilized in paleoceanographic studies. We present a modern Sr/Ca-δ18O-Sea Surface Temperature (SST) calibration of modern Isopora corals (n=3) collected from inner and outer reef locations ranging from 1-13m depth by Heron Island in the southern GBR in 2012. Pairing the Isopora Sr/Ca record with monthly SST yielded an average relationship of SST=-11.48×(Sr/Ca)+131.1 (r2 = 0.42-0.78). The Sr/Ca sensitivity of -0.087 mmol/mol/°C is similar to the sensitivity for Porites that was corrected for tissue layer smoothing effects determined by Gagan et al. (2012). The similarity between our Sr/Ca-SST sensitivity and the corrected sensitivity for Porites suggests tissue layer effects are minimal in Isopora. The mean annual SST amplitude recorded by the corals from 2008-2011 (full annual cycles) was 5.3°C and the average δ18O annual cycle of 1.1‰ approximates that expected if salinity had little effect on coral δ18O, assuming a previously established conversion of -0.23‰ (δ18O)/°C for biogenic aragonite. The average annual salinity amplitude of 0.3 in gridded data from around Heron Island supports our conclusion that δ18O variability is forced almost completely by SST. This modern Sr/Ca-SST calibration will expand the paleoceanographic utility of Isopora and, by assisting interpretation of Sr/Ca data from fossil corals collected during IODP 325, will better constrain the timing and magnitude of sea level changes and surface conditions since the Last

  9. High coral cover on a mesophotic, subtropical island platform at the limits of coral reef growth

    NASA Astrophysics Data System (ADS)

    Linklater, Michelle; Carroll, Andrew G.; Hamylton, Sarah M.; Jordan, Alan R.; Brooke, Brendan P.; Nichol, Scott L.; Woodroffe, Colin D.

    2016-11-01

    Balls Pyramid is a volcanic monolith rising 552 m from the Tasman Sea, 24 km southeast of the Pacific Ocean's southernmost modern coral reef at Lord Howe Island. High resolution seabed mapping of the shelf surrounding Balls Pyramid has revealed an extensive submerged reef structure in 30-50 m water depth, covering an area of 87 km2. Benthic community composition analysis of high-resolution still images revealed abundant scleractinian corals on the submerged reef, extending to a maximum depth of 94 m. Scleractinian coral occurred predominantly in 30-40 m depth where it comprised 13.3% of benthic cover within this depth range. Average scleractinian coral cover for all transects was 6.7±12.2%, with the highest average transect cover of 19.4±14.3% and up to 84% cover recorded for an individual still image. The remaining substrate comprised mixed benthos with veneers of carbonate sand. Benthic data were shown to significantly relate to the underlying geomorphology. BVSTEP analyses identified depth and backscatter as the strongest correlating explanatory variables driving benthic community structure. The prevalence of scleractinian corals on the submerged reef features at Balls Pyramid, and the mesophotic depths to which these corals extend, demonstrates the important role of this subtropical island shelf as habitat for modern coral communities in the southwest Pacific Ocean. As Balls Pyramid is located beyond the known latitudinal limit of coral reef formation, these findings have important implications for potential coral reef range expansion and deep reef refugia under a changing climate.

  10. USGS research on Atlantic coral reef ecosystems

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Yates, Kimberly K.; Zawada, David G.; Richey, Julie N.; Kellogg, Christina A.; Toth, Lauren T.

    2015-10-23

    Coral reefs are massive, biomineralized structures that protect coastal communities by acting as barriers to hazards such as hurricanes and tsunamis. They provide sand for beaches through the natural process of erosion, support tourism and recreational industries, and provide essential habitat for fisheries. The continuing global degradation of coral reef ecosystems is well documented. There is a need for focused, coordinated science to understand the complex physical and biological processes and interactions that are impacting the condition of coral reefs and their ability to respond to a changing environment.

  11. Climate-change refugia: shading reef corals by turbidity.

    PubMed

    Cacciapaglia, Chris; van Woesik, Robert

    2016-03-01

    Coral reefs have recently experienced an unprecedented decline as the world's oceans continue to warm. Yet global climate models reveal a heterogeneously warming ocean, which has initiated a search for refuges, where corals may survive in the near future. We hypothesized that some turbid nearshore environments may act as climate-change refuges, shading corals from the harmful interaction between high sea-surface temperatures and high irradiance. We took a hierarchical Bayesian approach to determine the expected distribution of 12 coral species in the Indian and Pacific Oceans, between the latitudes 37°N and 37°S, under representative concentration pathway 8.5 (W m(-2) ) by 2100. The turbid nearshore refuges identified in this study were located between latitudes 20-30°N and 15-25°S, where there was a strong coupling between turbidity and tidal fluctuations. Our model predicts that turbidity will mitigate high temperature bleaching for 9% of shallow reef habitat (to 30 m depth) - habitat that was previously considered inhospitable under ocean warming. Our model also predicted that turbidity will protect some coral species more than others from climate-change-associated thermal stress. We also identified locations where consistently high turbidity will likely reduce irradiance to <250 μmol m(-2)  s(-1) , and predict that 16% of reef-coral habitat ≤30 m will preclude coral growth and reef development. Thus, protecting the turbid nearshore refuges identified in this study, particularly in the northwestern Hawaiian Islands, the northern Philippines, the Ryukyu Islands (Japan), eastern Vietnam, western and eastern Australia, New Caledonia, the northern Red Sea, and the Arabian Gulf, should become part of a judicious global strategy for reef-coral persistence under climate change.

  12. Digital Reef Rugosity Estimates Coral Reef Habitat Complexity

    PubMed Central

    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. PMID:23437380

  13. Digital reef rugosity estimates coral reef habitat complexity.

    PubMed

    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.

  14. CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

    DTIC Science & Technology

    2003-09-30

    CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field Dr. Charles S. Yentsch Bigelow Laboratory McKown Point Road West...number. 1. REPORT DATE 30 SEP 2003 2. REPORT TYPE 3. DATES COVERED 00-00-2003 to 00-00-2003 4. TITLE AND SUBTITLE CoBOP Coral Reefs : Optical...Closure of a Coral Reef Submarine Light Field 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e

  15. Declining Coral Calcification on the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    De'ath, Glenn; Lough, Janice M.; Fabricius, Katharina E.

    2009-01-01

    Reef-building corals are under increasing physiological stress from a changing climate and ocean absorption of increasing atmospheric carbon dioxide. We investigated 328 colonies of massive Porites corals from 69 reefs of the Great Barrier Reef (GBR) in Australia. Their skeletal records show that throughout the GBR, calcification has declined by 14.2% since 1990, predominantly because extension (linear growth) has declined by 13.3%. The data suggest that such a severe and sudden decline in calcification is unprecedented in at least the past 400 years. Calcification increases linearly with increasing large-scale sea surface temperature but responds nonlinearly to annual temperature anomalies. The causes of the decline remain unknown; however, this study suggests that increasing temperature stress and a declining saturation state of seawater aragonite may be diminishing the ability of GBR corals to deposit calcium carbonate.

  16. Comparing Coral Reef Survey Methods. Unesco Reports in Marine Science No. 21 Report of a Regional Unesco/UNEP Workshop on Coral Reef Survey Management and Assessment Methods in Asia and the Pacific (Phuket, Thailand, December 13-17, 1982).

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France). Div. of Marine Sciences.

    This report includes nine papers prepared for a workshop on coral reef survey management and assessment methods in Asia and the Pacific. The papers are: "A Contrast in Methodologies between Surveying and Testing" (Charles Birkeland); "Coral Reef Survey Methods in the Andaman Sea" (Hansa Chansang); "A Review of Coral Reef…

  17. Environmentally controlled succession in a late Pleistocene coral reef (Sinai, Egypt)

    NASA Astrophysics Data System (ADS)

    Mewis, H.; Kiessling, W.

    2013-03-01

    The concept of ecological succession has been frequently applied in the study of ancient reefs. Whereas Paleozoic and Mesozoic reefs are commonly thought to reveal an autogenic primary—climax zonation, patterns in Neogene and Quaternary reefs are much more diverse. Here, we describe a well-preserved late Pleistocene coral reef from Dahab on Sinai Peninsula (Egypt), which shows a distinct zonation that resembles an ecological succession. In contrast to classical examples of ecological successions, species composition, paleoenvironmental conditions, and coral biodiversity of the Dahab reef indicate an allogenic, sea-level controlled community change, from marginal marine to reef slope and back reef. A review of the literature confirms that autogenic, short-term successions are virtually absent in Quaternary reefs. We predict that long generation times of corals make it unlikely that classical autogenic successions develop in reefs at all, unless environmental conditions are unusually stable.

  18. EPA Field Manual for Coral Reef Assessments

    EPA Science Inventory

    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 ...

  19. MANGROVE-DERIVED NUTRIENTS AND CORAL REEFS

    EPA Science Inventory

    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. Forecasted coral reef decline in marine biodiversity hotspots under climate change.

    PubMed

    Descombes, Patrice; Wisz, Mary S; Leprieur, Fabien; Parravicini, Valerianio; Heine, Christian; Olsen, Steffen M; Swingedouw, Didier; Kulbicki, Michel; Mouillot, David; Pellissier, Loïc

    2015-01-21

    Coral bleaching events threaten coral reef habitats globally and cause severe declines of local biodiversity and productivity. Related to high sea surface temperatures (SST), bleaching events are expected to increase as a consequence of future global warming. However, response to climate change is still uncertain as future low-latitude climatic conditions have no present-day analogue. Sea surface temperatures during the Eocene epoch were warmer than forecasted changes for the coming century, and distributions of corals during the Eocene may help to inform models forecasting the future of coral reefs. We coupled contemporary and Eocene coral occurrences with information on their respective climatic conditions to model the thermal niche of coral reefs and its potential response to projected climate change. We found that under the RCP8.5 climate change scenario, the global suitability for coral reefs may increase up to 16% by 2100, mostly due to improved suitability of higher latitudes. In contrast, in its current range, coral reef suitability may decrease up to 46% by 2100. Reduction in thermal suitability will be most severe in biodiversity hotspots, especially in the Indo-Australian Archipelago. Our results suggest that many contemporary hotspots for coral reefs, including those that have been refugia in the past, spatially mismatch with future suitable areas for coral reefs posing challenges to conservation actions under climate change.

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

    SciTech Connect

    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.

  2. African dust and the demise of Caribbean coral reefs

    USGS Publications Warehouse

    Shinn, E.A.; Smith, G.W.; Prospero, J.M.; Betzer, P.; Hayes, M.L.; Garrison, V.; Barber, R.T.

    2000-01-01

    The vitality of Caribbean coral reefs has undergone a continual state of decline since the late 1970s, a period of time coincidental with large increases in transatlantic dust transport. It is proposed that the hundreds of millions of tons/year of soil dust that have been crossing the Atlantic during the last 25 years could be a significant contributor to coral reef decline and may be affecting other ecosystems. Benchmark events, such as near synchronous Caribbean-wide mortalities of acroporid corals and the urchin Diadema in 1983, and coral bleaching beginning in 1987, correlate with the years of maximum dust flux into the Caribbean. Besides crustal elements, in particular Fe, Si, and aluminosilicate clays, the dust can serve as a substrate for numerous species of viable spores, especially the soil fungus Aspergillus. Aspergillus sydowii, the cause of an ongoing Caribbean-wide seafan disease, has been cultured from Caribbean air samples and used to inoculate sea fans.

  3. Cyphastrea kausti sp. n. (Cnidaria, Anthozoa, Scleractinia), a new species of reef coral from the Red Sea

    PubMed Central

    Bouwmeester, Jessica; Benzoni, Francesca; Baird, Andrew H.; Berumen, Michael L.

    2015-01-01

    Abstract A new scleractinian coral species, Cyphastrea kausti sp. n., is described from 13 specimens from the Red Sea. It is characterised by the presence of eight primary septa, unlike the other species of the genus, which have six, ten or 12 primary septa. The new species has morphological affinities with Cyphastrea microphthalma, from which it can be distinguished by the lower number of septa (on average eight instead of ten), and smaller calices and corallites. This species was observed in the northern and central Red Sea and appears to be absent from the southern Red Sea. PMID:25931952

  4. Turf algae-mediated coral damage in coastal reefs of Belize, Central America

    PubMed Central

    Jantzen, Carin; Kremb, Stephan Georg

    2014-01-01

    Many coral reefs in the Caribbean experienced substantial changes in their benthic community composition during the last decades. This often resulted in phase shifts from scleractinian coral dominance to that by other benthic invertebrate or algae. However, knowledge about how the related role of coral-algae contacts may negatively affect corals is scarce. Therefore, benthic community composition, abundance of algae grazers, and the abundance and character of coral-algae contacts were assessed in situ at 13 Belizean reef sites distributed along a distance gradient to the Belizean mainland (12–70 km): Mesoamerican Barrier Reef (inshore), Turneffe Atoll (inner and outer midshore), and Lighthouse Reef (offshore). In situ surveys revealed significantly higher benthic cover by scleractinian corals at the remote Lighthouse Reef (26–29%) when compared to the other sites (4–19%). The abundance of herbivorous fish and the sea urchin Diadema antillarum significantly increased towards the offshore reef sites, while the occurrence of direct coral-algae contacts consequently increased significantly with decreasing distance to shore. About 60% of these algae contacts were harmful (exhibiting coral tissue damage, pigmentation change, or overgrowth) for corals (mainly genera Orbicella and Agaricia), particularly when filamentous turf algae were involved. These findings provide support to the hypothesis that (turf) algae-mediated coral damage occurs in Belizean coastal, near-shore coral reefs. PMID:25276504

  5. Turf algae-mediated coral damage in coastal reefs of Belize, Central America.

    PubMed

    Wild, Christian; Jantzen, Carin; Kremb, Stephan Georg

    2014-01-01

    Many coral reefs in the Caribbean experienced substantial changes in their benthic community composition during the last decades. This often resulted in phase shifts from scleractinian coral dominance to that by other benthic invertebrate or algae. However, knowledge about how the related role of coral-algae contacts may negatively affect corals is scarce. Therefore, benthic community composition, abundance of algae grazers, and the abundance and character of coral-algae contacts were assessed in situ at 13 Belizean reef sites distributed along a distance gradient to the Belizean mainland (12-70 km): Mesoamerican Barrier Reef (inshore), Turneffe Atoll (inner and outer midshore), and Lighthouse Reef (offshore). In situ surveys revealed significantly higher benthic cover by scleractinian corals at the remote Lighthouse Reef (26-29%) when compared to the other sites (4-19%). The abundance of herbivorous fish and the sea urchin Diadema antillarum significantly increased towards the offshore reef sites, while the occurrence of direct coral-algae contacts consequently increased significantly with decreasing distance to shore. About 60% of these algae contacts were harmful (exhibiting coral tissue damage, pigmentation change, or overgrowth) for corals (mainly genera Orbicella and Agaricia), particularly when filamentous turf algae were involved. These findings provide support to the hypothesis that (turf) algae-mediated coral damage occurs in Belizean coastal, near-shore coral reefs.

  6. Coral Bleaching: Coral 'refugia' amid heating seas

    NASA Astrophysics Data System (ADS)

    Caldeira, Ken

    2013-05-01

    The Earth is getting hotter as carbon dioxide, predominantly from the burning of fossil fuels, continues to accumulate in the atmosphere. It is widely recognized that increasing temperatures pose a threat to coral reefs, but just how large a risk are these reefs facing?

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

    PubMed

    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 <10% on black 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.

  8. Evaluation of Stony Coral Indicators for Coral Reef Management.

    EPA Science Inventory

    Colonies of reef-building stony corals at 57 stations around St. Croix, U.S. Virgin Islands were characterized by species, size and percentage of living tissue. Taxonomic, biological and physical indicators of coral condition were derived from these measurements and assessed for ...

  9. Effects of season, sex and body size on the feeding ecology of turtle-headed sea snakes ( Emydocephalus annulatus) on IndoPacific inshore coral reefs

    NASA Astrophysics Data System (ADS)

    Goiran, C.; Dubey, S.; Shine, R.

    2013-06-01

    In terrestrial snakes, many cases of intraspecific shifts in dietary habits as a function of predator sex and body size are driven by gape limitation and hence are most common in species that feed on relatively large prey and exhibit a wide body-size range. Our data on sea snakes reveal an alternative mechanism for intraspecific niche partitioning, based on sex-specific seasonal anorexia induced by reproductive activities. Turtle-headed sea snakes ( Emydocephalus annulatus) on coral reefs in the New Caledonian Lagoon feed entirely on the eggs of demersal-spawning fishes. DNA sequence data (cytochrome b gene) on eggs that we palpated from stomachs of 37 snakes showed that despite this ontogenetic stage specialization, the prey comes from a taxonomically diverse array of species including damselfish (41 % of samples, at least 5 species), blennies (41 %, 4 species) and gobies (19 %, 5 species). The composition of snake diets shifted seasonally (with damselfish dominating in winter but not summer), presumably reflecting seasonality of fish reproduction. That seasonal shift affects male and female snakes differently, because reproduction is incompatible with foraging. Adult female sea snakes ceased feeding when they became heavily distended with developing embryos in late summer, and males ceased feeding while they were mate searching in winter. The sex divergence in foraging habits may be amplified by sexual size dimorphism; females grow larger than males, and larger snakes (of both sexes) feed more on damselfish (which often lay their eggs in exposed sites) than on blennies and gobies (whose eggs are hidden within narrow crevices). Specific features of reproductive biology of coral reef fish (seasonality and nest type) have generated intraspecific niche partitioning in these sea snakes, by mechanisms different from those that apply to terrestrial snakes.

  10. Coral diseases and bleaching on Colombian Caribbean coral reefs.

    PubMed

    Navas-Camacho, Raúl; Gil-Agudelo, Diego Luis; Rodríguez-Ramírez, Alberto; Reyes-Nivia, María Catalina; Garzón-Ferreira, Jaime

    2010-05-01

    Since 1998 the National Monitoring System for the Coral Reefs of Colombia (SIMAC) has monitored the occurrence of coral bleaching and diseases in some Colombian coral reefs (permanent stations at San Andres Island, Rosario Islands, Tayrona, San Bernardo Islands and Urabá). The main purpose is to evaluate their health status and to understand the factors that have been contributing to their decline. To estimate these occurrences, annual surveys in 126 permanent belt transects (10 x 2m) with different depth intervals (3-6 meters, 9-12 meters and 15-18 meters) are performed at all reef sites. Data from the 1998-2004 period, revealed that San Andrés Island had many colonies with diseases (38.9 colonies/m2), and Urabá had high numbers with bleaching (54.4 colonies/m2). Of the seven reported coral diseases studied, Dark Spots Disease (DSD), and White Plague Disease (WPD) were noteworthy because they occurred in all Caribbean monitored sites, and because of their high interannual infection incidence. Thirty five species of scleractinian corals were affected by at least one disease and a high incidence of coral diseases on the main reef builders is documented. Bleaching was present in 34 species. During the whole monitoring period, Agaricia agaricites and Siderastrea siderea were the species most severely affected by DSD and bleaching, respectively. Diseases on species such as Agaricia fragilis, A. grahamae, A. humilis, Diploria clivosa, Eusmilia fastigiata, Millepora complanata, and Mycetophyllia aliciae are recorded for first time in Colombia. We present bleaching and disease incidences, kinds of diseases, coral species affected, reef localities studied, depth intervals of surveys, and temporal (years) variation for each geographic area. This variation makes difficult to clearly determine defined patterns or general trends for monitored reefs. This is the first long-term study of coral diseases and bleaching in the Southwestern Caribbean, and one of the few long

  11. Ecological Risk Assessment of Munitions Compounds on Coral and Coral Reef Health

    DTIC Science & Technology

    2014-01-01

    FINAL REPORT Ecological Risk Assessment of Munitions Compounds on Coral and Coral Reef Health SERDP Project ER-2125 January 2014...COVERED 00-10-2011 to 00-01-2014 4. TITLE AND SUBTITLE Ecological Risk Assessment of Munitions Compounds on Coral and Coral Reef Health 5a. CONTRACT...impact corals , and to determine the ecological risk they may pose to coral and coral reef health. At the outset of this project, we were asked by the

  12. Water column productivity and temperature predict coral reef regeneration across the Indo-Pacific

    PubMed Central

    Riegl, B.; Glynn, P. W.; Wieters, E.; Purkis, S.; d'Angelo, C.; Wiedenmann, J.

    2015-01-01

    Predicted increases in seawater temperatures accelerate coral reef decline due to mortality by heat-driven coral bleaching. Alteration of the natural nutrient environment of reef corals reduces tolerance of corals to heat and light stress and thus will exacerbate impacts of global warming on reefs. Still, many reefs demonstrate remarkable regeneration from past stress events. This paper investigates the effects of sea surface temperature (SST) and water column productivity on recovery of coral reefs. In 71 Indo-Pacific sites, coral cover changes over the past 1-3 decades correlated negative-exponentially with mean SST, chlorophyll a, and SST rise. At six monitoring sites (Persian/Arabian Gulf, Red Sea, northern and southern Galápagos, Easter Island, Panama), over half of all corals were <31 years, implying that measured environmental variables indeed shaped populations and community. An Indo-Pacific-wide model suggests reefs in the northwest and central Indian Ocean, as well as the central west Pacific, are at highest risk of degradation, and those at high latitudes the least. The model pinpoints regions where coral reefs presently have the best chances for survival. However, reefs best buffered against temperature and nutrient effects are those that current studies suggest to be most at peril from future ocean acidification. PMID:25653128

  13. Water column productivity and temperature predict coral reef regeneration across the Indo-Pacific

    NASA Astrophysics Data System (ADS)

    Riegl, B.; Glynn, P. W.; Wieters, E.; Purkis, S.; D'Angelo, C.; Wiedenmann, J.

    2015-02-01

    Predicted increases in seawater temperatures accelerate coral reef decline due to mortality by heat-driven coral bleaching. Alteration of the natural nutrient environment of reef corals reduces tolerance of corals to heat and light stress and thus will exacerbate impacts of global warming on reefs. Still, many reefs demonstrate remarkable regeneration from past stress events. This paper investigates the effects of sea surface temperature (SST) and water column productivity on recovery of coral reefs. In 71 Indo-Pacific sites, coral cover changes over the past 1-3 decades correlated negative-exponentially with mean SST, chlorophyll a, and SST rise. At six monitoring sites (Persian/Arabian Gulf, Red Sea, northern and southern Galápagos, Easter Island, Panama), over half of all corals were <31 years, implying that measured environmental variables indeed shaped populations and community. An Indo-Pacific-wide model suggests reefs in the northwest and central Indian Ocean, as well as the central west Pacific, are at highest risk of degradation, and those at high latitudes the least. The model pinpoints regions where coral reefs presently have the best chances for survival. However, reefs best buffered against temperature and nutrient effects are those that current studies suggest to be most at peril from future ocean acidification.

  14. Water column productivity and temperature predict coral reef regeneration across the Indo-Pacific.

    PubMed

    Riegl, B; Glynn, P W; Wieters, E; Purkis, S; d'Angelo, C; Wiedenmann, J

    2015-02-05

    Predicted increases in seawater temperatures accelerate coral reef decline due to mortality by heat-driven coral bleaching. Alteration of the natural nutrient environment of reef corals reduces tolerance of corals to heat and light stress and thus will exacerbate impacts of global warming on reefs. Still, many reefs demonstrate remarkable regeneration from past stress events. This paper investigates the effects of sea surface temperature (SST) and water column productivity on recovery of coral reefs. In 71 Indo-Pacific sites, coral cover changes over the past 1-3 decades correlated negative-exponentially with mean SST, chlorophyll a, and SST rise. At six monitoring sites (Persian/Arabian Gulf, Red Sea, northern and southern Galápagos, Easter Island, Panama), over half of all corals were <31 years, implying that measured environmental variables indeed shaped populations and community. An Indo-Pacific-wide model suggests reefs in the northwest and central Indian Ocean, as well as the central west Pacific, are at highest risk of degradation, and those at high latitudes the least. The model pinpoints regions where coral reefs presently have the best chances for survival. However, reefs best buffered against temperature and nutrient effects are those that current studies suggest to be most at peril from future ocean acidification.

  15. Patterns in the distribution of soft corals across the central Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Dinesen, Z. D.

    1983-05-01

    Distribution patterns of soft coral genera were examined at 11 reefs situated in a broad transect from inshore to the Coral Sea in the central region of the Great Barrier Reef. Twenty-five genera representing the Orders Alcyonacea and Stolonifera were recorded, and the survey also included one genus of the Order Gorgonacea. Total living soft coral cover is greatest on outershelf reef slopes, and is often less than and inversely related to the cover by stony corals. Soft coral diversity is generally low on reef flats, where soft coral cover is low or nil except in protected, inshore areas. The most diverse assemblages occur on reef slopes in midshelf and outershelf areas, where Efflatounaria and nephtheid genera predominate, and widely distributed alcyoniid genera are common. These richer assemblages are less well represented in the Coral Sea, while innershelf reefs support a less diverse fauna of somewhat different generic composition. Distribution patterns of soft corals across the transect broadly match similar variations in the distributions of stony corals and fishes, inshore reefs being generally depauperate. Such variations across the continental shelf are closely associated with changes in prevailing environmental conditions, but further research will be required to elucidate the effects of environmental parameters on benthic community structure.

  16. Coral reef formation theory may apply to oil, gas exploration

    SciTech Connect

    Not Available

    1990-12-10

    This paper reports a coral reef formation theory that has implications for hydrocarbon exploration. The theory states that many coral reefs and carbonate buildups from at and are dependent upon nutrient rich fluids seeping through the seabed.

  17. New protection initiatives announced for coral reefs

    NASA Astrophysics Data System (ADS)

    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.

  18. Resetting predator baselines in coral reef ecosystems

    PubMed Central

    Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P.; McCauley, Douglas J.; Pollock, Kydd; Pollock, Amanda; Kendall, Bruce E.; Gaines, Steven D.; Caselle, Jennifer E.

    2017-01-01

    What did coral reef ecosystems look like before human impacts became pervasive? Early efforts to reconstruct baselines resulted in the controversial suggestion that pristine coral reefs have inverted trophic pyramids, with disproportionally large top predator biomass. The validity of the coral reef inverted trophic pyramid has been questioned, but until now, was not resolved empirically. We use data from an eight-year tag-recapture program with spatially explicit, capture-recapture models to re-examine the population size and density of a key top predator at Palmyra atoll, the same location that inspired the idea of inverted trophic biomass pyramids in coral reef ecosystems. Given that animal movement is suspected to have significantly biased early biomass estimates of highly mobile top predators, we focused our reassessment on the most mobile and most abundant predator at Palmyra, the grey reef shark (Carcharhinus amblyrhynchos). We estimated a density of 21.3 (95% CI 17.8, 24.7) grey reef sharks/km2, which is an order of magnitude lower than the estimates that suggested an inverted trophic pyramid. Our results indicate that the trophic structure of an unexploited reef fish community is not inverted, and that even healthy top predator populations may be considerably smaller, and more precarious, than previously thought. PMID:28220895

  19. Resetting predator baselines in coral reef ecosystems.

    PubMed

    Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P; McCauley, Douglas J; Pollock, Kydd; Pollock, Amanda; Kendall, Bruce E; Gaines, Steven D; Caselle, Jennifer E

    2017-02-21

    What did coral reef ecosystems look like before human impacts became pervasive? Early efforts to reconstruct baselines resulted in the controversial suggestion that pristine coral reefs have inverted trophic pyramids, with disproportionally large top predator biomass. The validity of the coral reef inverted trophic pyramid has been questioned, but until now, was not resolved empirically. We use data from an eight-year tag-recapture program with spatially explicit, capture-recapture models to re-examine the population size and density of a key top predator at Palmyra atoll, the same location that inspired the idea of inverted trophic biomass pyramids in coral reef ecosystems. Given that animal movement is suspected to have significantly biased early biomass estimates of highly mobile top predators, we focused our reassessment on the most mobile and most abundant predator at Palmyra, the grey reef shark (Carcharhinus amblyrhynchos). We estimated a density of 21.3 (95% CI 17.8, 24.7) grey reef sharks/km(2), which is an order of magnitude lower than the estimates that suggested an inverted trophic pyramid. Our results indicate that the trophic structure of an unexploited reef fish community is not inverted, and that even healthy top predator populations may be considerably smaller, and more precarious, than previously thought.

  20. ReefGrow v2.0: A classroom tool for visualizing the processes controlling coral reef development and demise

    NASA Astrophysics Data System (ADS)

    Chase, A. C.; Clague, D.; Webster, J.; Berger, W.; Schramm, R.; Winterer, J.

    2004-12-01

    Understanding the complex interplay between coral reef growth, sea-level variations and tectonics is a major challenge in paleoclimate research. A continuing challenge for students is how to visualize the complex interplay of different geological processes through time. The Monterey Bay Aquarium Research Institute (MBARI) has developed ReefGrow v2.0, a Java-based program that numerically models and displays coral reef growth in 2D. The program was developed initially as a research tool but has educational applications as well. Based on straightforward mathematical algorithms, ReefGrow v2.0, realistically "grows" reefs in response to different variables (including subsidence or uplift rate, coral growth rate, sedimentation rate, dissolution rate when the reef is subaerially exposed). The program can import a bathymetric profile to use as the substrate, can import different sea level curves, and can vary the subsidence, or uplift, rates as a function of distance from the shoreline. A major strength of ReefGrow v2.0 is its simple graphical interface, allowing variables to be changed and their impacts on reef development readily assessed. Students are able to view the models' output in the form of a dynamic 2D cross section that steps forward or back through time. To illustrate its use, we applied ReefGrow v2.0 to a "real world" situation using published data from drowned fossil coral reefs that grew on the subsiding flanks of Hawaii over the last 500 ka. ReefGrow v.2.0 was able to realistically model the number and morphology of the reef terraces. The models can be used to constrain the timing of coral reef drowning, the rate and shape of island subsidence, the timing of subaerial exposure of each reef, and the rate of coral growth required to mimic the morphology of the reef. The cross section shows the internal structure of the reef. The program can also be used to forward model reef growth in response to future climate change that causes sea-level rise, or

  1. Developing a multi-stressor gradient for coral reefs

    EPA Science Inventory

    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...

  2. 78 FR 67128 - Coral Reef Conservation Program; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-08

    ... National Oceanic and Atmospheric Administration Coral Reef Conservation Program; Meeting AGENCY: Coral Reef... of public comment. SUMMARY: Notice is hereby given of a public meeting of the U.S. Coral Reef Task.../uscrtf-registration-form . Commenters may address the meeting, the role of the USCRTF, or general...

  3. Coral Reefs: A Gallery Program, Grades 7-12.

    ERIC Educational Resources Information Center

    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…

  4. Potential role of the ocean thermostat in determining regional differences in coral reef bleaching events

    NASA Astrophysics Data System (ADS)

    Kleypas, Joan A.; Danabasoglu, Gokhan; Lough, Janice M.

    2008-02-01

    Several negative feedback mechanisms have been proposed by others to explain the stability of maximum sea surface temperature (SST) in the western Pacific warm pool (WPWP). If these ``ocean thermostat'' mechanisms effectively suppress warming in the future, then coral reefs in this region should be less exposed to conditions that favor coral reef bleaching. In this study we look for regional differences in reef exposure and sensitivity to increasing SSTs by comparing reported coral reef bleaching events with observed and modeled SSTs of the last fifty years. Coral reefs within or near the WPWP have had fewer reported bleaching events relative to reefs in other regions. Analysis of SST data indicate that the warmest parts of the WPWP have warmed less than elsewhere in the tropical oceans, which supports the existence of thermostat mechanisms that act to depress warming beyond certain temperature thresholds.

  5. Seasonal Dynamical Prediction of Coral Bleaching in the Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Spillman, C. M.; Alves, O.

    2009-05-01

    Sea surface temperature (SST) is now recognised as the primary cause of mass coral bleaching events. Coral bleaching occurs during times of stress, particularly when SSTs exceed the coral colony's tolerance level. Global warming is potentially a serious threat to the future of the world's reef systems with predictions by the international community that bleaching will increase in both frequency and severity. Advance warning of anomalous sea surface temperatures, and thus potential bleaching events, would allow for the implementation of management strategies to minimise reef damage. Seasonal SST forecasts from the coupled ocean-atmosphere model POAMA (Bureau of Meteorology) have skill in the Great Barrier Reef (Australia) several months into the future. We will present model forecasts and probabilistic products for use in reef management, and assess model skill in the region. These products will revolutionise the way in which coral bleaching events are monitored and assessed in the Great Barrier Reef and Australian region.

  6. How will coral reef fish communities respond to climate-driven disturbances? Insight from landscape-scale perturbations.

    PubMed

    Adam, Thomas C; Brooks, Andrew J; Holbrook, Sally J; Schmitt, Russell J; Washburn, Libe; Bernardi, Giacomo

    2014-09-01

    Global climate change is rapidly altering disturbance regimes in many ecosystems including coral reefs, yet the long-term impacts of these changes on ecosystem structure and function are difficult to predict. A major ecosystem service provided by coral reefs is the provisioning of physical habitat for other organisms, and consequently, many of the effects of climate change on coral reefs will be mediated by their impacts on habitat structure. Therefore, there is an urgent need to understand the independent and combined effects of coral mortality and loss of physical habitat on reef-associated biota. Here, we use a unique series of events affecting the coral reefs around the Pacific island of Moorea, French Polynesia to differentiate between the impacts of coral mortality and the degradation of physical habitat on the structure of reef fish communities. We found that, by removing large amounts of physical habitat, a tropical cyclone had larger impacts on reef fish communities than an outbreak of coral-eating sea stars that caused widespread coral mortality but left the physical structure intact. In addition, the impacts of declining structural complexity on reef fish assemblages accelerated as structure became increasingly rare. Structure provided by dead coral colonies can take up to decades to erode following coral mortality, and, consequently, our results suggest that predictions based on short-term studies are likely to grossly underestimate the long-term impacts of coral decline on reef fish communities.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  9. Genetic Population Structure of the Coral Reef Sea Star Linckia laevigata in the Western Indian Ocean and Indo-West Pacific

    PubMed Central

    Kochzius, Marc

    2016-01-01

    The coral reef sea star Linckia laevigata is common on shallow water coral reefs of the Indo-West Pacific. Its large geographic distribution and comprehensive data from previous studies makes it suitable to examine genetic differentiation and connectivity over large geographical scales. Based on partial sequences of the mitochondrial cytochrome oxidase I (COI) gene this study investigates the genetic population structure and connectivity of L. laevigata in the Western Indian Ocean (WIO) and compares it to previous studies in the Indo-Malay-Philippines Archipelago (IMPA). A total of 138 samples were collected from nine locations in the WIO. AMOVA revealed a low but significant ΦST-value of 0.024 for the WIO populations. In the hierarchical AMOVA, the following grouping rejected the hypothesis of panmixia: (1) Kenya (Watamu, Mombasa, Diani) and Tanzanian Island populations (Misali and Jambiani) and (2) the rest of the WIO sites (mainland Tanzania and Madagascar; ΦCT = 0.03). The genetic population structure was stronger and more significant (ΦST = 0.13) in the comparative analysis of WIO and IMPA populations. Three clades were identified in the haplotype network. The strong genetic differentiation (ΦCT = 0.199, P < 0.001) suggests that Indo-West Pacific populations of L. laevigata can be grouped into four biogeographic regions: (1) WIO (2) Eastern Indian Ocean (3) IMPA and (4) Western Pacific. The findings of this study support the existence of a genetic break in the Indo-West Pacific consistent with the effect of lowered sea level during the Pleistocene, which limited gene flow between the Pacific and Indian Ocean. PMID:27798700

  10. Genetic Population Structure of the Coral Reef Sea Star Linckia laevigata in the Western Indian Ocean and Indo-West Pacific.

    PubMed

    Otwoma, Levy Michael; Kochzius, Marc

    2016-01-01

    The coral reef sea star Linckia laevigata is common on shallow water coral reefs of the Indo-West Pacific. Its large geographic distribution and comprehensive data from previous studies makes it suitable to examine genetic differentiation and connectivity over large geographical scales. Based on partial sequences of the mitochondrial cytochrome oxidase I (COI) gene this study investigates the genetic population structure and connectivity of L. laevigata in the Western Indian Ocean (WIO) and compares it to previous studies in the Indo-Malay-Philippines Archipelago (IMPA). A total of 138 samples were collected from nine locations in the WIO. AMOVA revealed a low but significant ΦST-value of 0.024 for the WIO populations. In the hierarchical AMOVA, the following grouping rejected the hypothesis of panmixia: (1) Kenya (Watamu, Mombasa, Diani) and Tanzanian Island populations (Misali and Jambiani) and (2) the rest of the WIO sites (mainland Tanzania and Madagascar; ΦCT = 0.03). The genetic population structure was stronger and more significant (ΦST = 0.13) in the comparative analysis of WIO and IMPA populations. Three clades were identified in the haplotype network. The strong genetic differentiation (ΦCT = 0.199, P < 0.001) suggests that Indo-West Pacific populations of L. laevigata can be grouped into four biogeographic regions: (1) WIO (2) Eastern Indian Ocean (3) IMPA and (4) Western Pacific. The findings of this study support the existence of a genetic break in the Indo-West Pacific consistent with the effect of lowered sea level during the Pleistocene, which limited gene flow between the Pacific and Indian Ocean.

  11. Climate change, global warming and coral reefs: modelling the effects of temperature.

    PubMed

    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.

  12. Human Disruption of Coral Reef Trophic Structure.

    PubMed

    Graham, Nicholas A J; McClanahan, Tim R; MacNeil, M Aaron; Wilson, Shaun K; Cinner, Joshua E; Huchery, Cindy; Holmes, Thomas H

    2017-01-23

    The distribution of biomass among trophic levels provides a theoretical basis for understanding energy flow and the hierarchical structure of animal communities. In the absence of energy subsidies [1], bottom-heavy trophic pyramids are expected to predominate, based on energy transfer efficiency [2] and empirical evidence from multiple ecosystems [3]. However, the predicted pyramid of biomass distribution among trophic levels may be disrupted through trophic replacement by alternative organisms in the ecosystem, trophic cascades, and humans preferentially impacting specific trophic levels [4-6]. Using empirical data spanning >250 coral reefs, we show how trophic pyramid shape varies given human-mediated gradients along two orders of magnitude in reef fish biomass. Mean trophic level of the assemblage increased modestly with decreasing biomass, contrary to predictions of fishing down the food web [7]. The mean trophic level pattern is explained by trophic replacement of herbivorous fish by sea urchins at low biomass and the accumulation of slow-growing, large-bodied, herbivorous fish at high biomass. Further, at high biomass, particularly where fishers are not selectively removing higher trophic level individuals, a concave trophic distribution emerges. The concave trophic distribution implies a more direct link between lower and upper trophic levels, which may confer greater energy efficiency. This trophic distribution emerges when community biomass exceeds ∼650 kg/ha, suggesting that fisheries for upper trophic level species will only be supported under lightly fished scenarios.

  13. Status and trends of Caribbean coral reefs: 1970-2012

    USGS Publications Warehouse

    Jackson, Jeremy; Donovan, Mary; Cramer, Katie; Lam, Vivian

    2014-01-01

    This it the 9th status report since the Global Coral Reef Monitoring Network (GCRMN) was founded in 1995 was the data arm of the International Coral Reef Initiative (ICRI) to document the ecological condition or corral reefs, strengthen monitoring efforts, and link existing organizations and people working on reefs worldwide. The US Government provided the initial funding to help set up a global network of coral reef workers and has continued to provide core support. Since then, the series of reports have aimed to present the current status of coral reefs of the world or particular regions, the major threats to reefs and their consequences, and any initiative undertaken under the auspices of ICRI or other bodies to arrest or reverse the decline of coral reefs. IUCN assumed responsibility for hosting the global coordination of the GCRMN in 2010 under the scientific direction of Jeremy Jackson with the following objectives: 1. Document quantitatively the global status and trends for corals, macroalgae, sea urchins, and fishes based on available data from individual scientists as well as the peer reviewed scientific literature, monitoring programs, and report. 2. Bring together regional experts in a series of workshops to involve them in data compilation, analysis, and synthesis. 3. Integrate coral reef status and trends with independent environmental, management, and socioeconomic data to better understand the primary factors responsible for coral reef decline, the possible synergies among factors that may further magnify their impacts, and how these stresses may be more effectively alleviated. Work with GCRMN partners to establish simple and practical standardized protocols for future monitoring and assessment. Disseminate information and results to help guide member state policy and actions. The overarching objective is to understand why some reefs are much healthier than others, to identify what kinds of actions have been particularly beneficial or harmful, and to

  14. Patterns in the distribution of coral communities across the central Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Done, T. J.

    1982-10-01

    Despite the pre-eminence of the Great Barrier Reef, there has been little systematic description of its biotic communities, and in particular, of the corals themselves. Only recently have the problems of coral taxonomy been sufficiently resolved to allow a beginning to be made in rectifying this deficiency. The present study describes seventeen assemblages of corals which occupy the major habitat types found in and near the central Great Barrier Reef. The habitats studied range from the wave swept reef flats of Coral Sea atolls to the slopes of small reefs occupying sheltered, muddy conditions near the coast. These, and the array of reefs between, have characteristic suites of coral communities which provide the basis for a classification of reefs into non- Acropora reefs and various Acropora reefs. It is speculated that the faunistic differences are maintained because reefs are primarily self-seeded and because the majority of larvae from external sources are of species which are already present. The greatest diversity of both species and community types was found on reefs near the middle of the continental shelf, while the oceanic atolls and nearshore silt-affected reefs are almost equally depauperate.

  15. Direct and indirect effects of high pCO2 on algal grazing by coral reef herbivores from the Gulf of Aqaba (Red Sea)

    NASA Astrophysics Data System (ADS)

    Borell, E. M.; Steinke, M.; Fine, M.

    2013-12-01

    Grazing on marine macroalgae is a key structuring process for coral reef communities. However, ocean acidification from rising atmospheric CO2 concentrations is predicted to adversely affect many marine animals, while seaweed communities may benefit and prosper. We tested how exposure to different pCO2 (400, 1,800 and 4,000 μatm) may affect grazing on the green alga Ulva lactuca by herbivorous fish and sea urchins from the coral reefs in the northern Gulf of Aqaba (Red Sea), either directly, by changing herbivore behaviour, or indirectly via changes in algal palatability. We also determined the effects of pCO2 on algal tissue concentrations of protein and the grazing-deterrent secondary metabolite dimethylsulfoniopropionate (DMSP). Grazing preferences and overall consumption were tested in a series of multiple-choice feeding experiments in the laboratory and in situ following exposure for 14 d (algae) and 28 d (herbivores). 4,000 μatm had a significant effect on the biochemical composition and palatability of U. lactuca. No effects were observed at 1,800 relative to 400 μatm (control). Exposure of U. lactuca to 4,000 μatm resulted in a significant decrease in protein and increase in DMSP concentration. This coincided with a reduced preference for these algae by the sea urchin Tripneustes gratilla and different herbivorous fish species in situ (Acanthuridae, Siganidae and Pomacanthidae). No feeding preferences were observed for the rabbitfish Siganus rivulatus under laboratory conditions. Exposure to elevated pCO2 had no direct effect on the overall algal consumption by T. gratilla and S. rivulatus. Our results show that CO2 has the potential to alter algal palatability to different herbivores which could have important implications for algal abundance and coral community structure. The fact that pCO2 effects were observed only at a pCO2 of 4,000 μatm, however, indicates that algal-grazer interactions may be resistant to predicted pCO2 concentrations in the

  16. Quaternary coral reef refugia preserved fish diversity.

    PubMed

    Pellissier, Loïc; Leprieur, Fabien; Parravicini, Valeriano; Cowman, Peter F; Kulbicki, Michel; Litsios, Glenn; Olsen, Steffen M; Wisz, Mary S; Bellwood, David R; Mouillot, David

    2014-05-30

    The most prominent pattern in global marine biogeography is the biodiversity peak in the Indo-Australian Archipelago. Yet the processes that underpin this pattern are still actively debated. By reconstructing global marine paleoenvironments over the past 3 million years on the basis of sediment cores, we assessed the extent to which Quaternary climate fluctuations can explain global variation in current reef fish richness. Comparing global historical coral reef habitat availability with the present-day distribution of 6316 reef fish species, we find that distance from stable coral reef habitats during historical periods of habitat loss explains 62% of the variation in fish richness, outweighing present-day environmental factors. Our results highlight the importance of habitat persistence during periods of climate change for preserving marine biodiversity.

  17. Extinction vulnerability of coral reef fishes

    PubMed Central

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

    2011-01-01

    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. PMID:21320260

  18. Pachyseris inattesa sp. n. (Cnidaria, Anthozoa, Scleractinia): a new reef coral species from the Red Sea and its phylogenetic relationships

    PubMed Central

    Terraneo, Tullia I.; Berumen, Michael L.; Arrigoni, Roberto; Waheed, Zarinah; Bouwmeester, Jessica; Caragnano, Annalisa; Stefani, Fabrizio; Benzoni, Francesca

    2014-01-01

    Abstract A new scleractinian coral species, Pachyseris inattesa sp. n., is described from the Red Sea. Despite a superficial resemblance with some species in the agariciid genus Leptoseris with which it has been previously confused, P. inattesa sp. n. has micro-morphological characters typical of the genus Pachyseris. This genus, once part of the Agariciidae, is comprised of five extant species and is widely distributed throughout the tropical Indo-Pacific. It is currently incertae sedis as a result of recent molecular analysis and appears to be closely related to the Euphylliidae. A molecular phylogenetic reconstruction including P. inattesa sp. n., the genus type species P. rugosa, and P. speciosa, all present in the Red Sea, was performed using the mitochondrial intergenic spacer between COI and 16S-rRNA. The results confirm that P. inattesa sp. n. is a monophyletic lineage closely related to the other Pachyseris species examined. PMID:25152672

  19. Effects of the 1998 coral morality event on Kenyan coral reefs and fisheries.

    PubMed

    McClanahan, Tim; Maina, Joseph; Pet-Soede, Lida

    2002-12-01

    Data were collected in southern Kenya on coral reef ecosystems and fisheries to assess the influence of the 1998 coral bleaching and mortality event. We compared benthic cover, sea urchin and fish abundance in unfished marine parks and fished reefs and the reef-associated fisheries 3 years before and after 1998. Hard and soft coral decreased while coralline algae increased in both management areas. Turf increased in marine parks and sponge and fleshy algae increased in the fished reefs. Sea urchin grazer biomass was unchanged over this period and the fish community changed less than benthic cover. In general, butterflyfish, damselfish and wrasses were negatively influenced while surgeonfish and a few uncommon families were positively influenced by the substratum change. There was a 17% increase in fishing effort as measured by fishermen per day at each landing site and the total demersal catch declined by 8% and the catch per man declined by 21% after 1998. The decline in the total catch and CPUE combined with the increase in effort suggest an overexploited fishery and this makes it difficult to distinguish changes caused by coral mortality or fishing effort. The price of fish increased over this period and this caused an 18% increase in the total value of the fishery but no difference in the net income of individual fishermen.

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

    SciTech Connect

    Mazzullo, S.J.; Anderson-Underwood, K.E.; Burke, C.D.; Bischoff, W.D. )

    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.

  1. Colour thresholds in a coral reef fish

    PubMed Central

    Vorobyev, M.; Marshall, N. J.

    2016-01-01

    Coral reef fishes are among the most colourful animals in the world. Given the diversity of lifestyles and habitats on the reef, it is probable that in many instances coloration is a compromise between crypsis and communication. However, human observation of this coloration is biased by our primate visual system. Most animals have visual systems that are ‘tuned’ differently to humans; optimized for different parts of the visible spectrum. To understand reef fish colours, we need to reconstruct the appearance of colourful patterns and backgrounds as they are seen through the eyes of fish. Here, the coral reef associated triggerfish, Rhinecanthus aculeatus, was tested behaviourally to determine the limits of its colour vision. This is the first demonstration of behavioural colour discrimination thresholds in a coral reef species and is a critical step in our understanding of communication and speciation in this vibrant colourful habitat. Fish were trained to discriminate between a reward colour stimulus and series of non-reward colour stimuli and the discrimination thresholds were found to correspond well with predictions based on the receptor noise limited visual model and anatomy of the eye. Colour discrimination abilities of both reef fish and a variety of animals can therefore now be predicted using the parameters described here. PMID:27703704

  2. Colour thresholds in a coral reef fish.

    PubMed

    Champ, C M; Vorobyev, M; Marshall, N J

    2016-09-01

    Coral reef fishes are among the most colourful animals in the world. Given the diversity of lifestyles and habitats on the reef, it is probable that in many instances coloration is a compromise between crypsis and communication. However, human observation of this coloration is biased by our primate visual system. Most animals have visual systems that are 'tuned' differently to humans; optimized for different parts of the visible spectrum. To understand reef fish colours, we need to reconstruct the appearance of colourful patterns and backgrounds as they are seen through the eyes of fish. Here, the coral reef associated triggerfish, Rhinecanthus aculeatus, was tested behaviourally to determine the limits of its colour vision. This is the first demonstration of behavioural colour discrimination thresholds in a coral reef species and is a critical step in our understanding of communication and speciation in this vibrant colourful habitat. Fish were trained to discriminate between a reward colour stimulus and series of non-reward colour stimuli and the discrimination thresholds were found to correspond well with predictions based on the receptor noise limited visual model and anatomy of the eye. Colour discrimination abilities of both reef fish and a variety of animals can therefore now be predicted using the parameters described here.

  3. High-resolution Sr/Ca ratios in a Porites lutea coral from Lakshadweep Archipelago, southeast Arabian Sea: An example from a region experiencing steady rise in the reef temperature

    NASA Astrophysics Data System (ADS)

    Sagar, Netramani; Hetzinger, Steffen; Pfeiffer, Miriam; Masood Ahmad, Syed; Dullo, Wolf-Christian; Garbe-Schönberg, Dieter

    2016-01-01

    Here we present the first record of Sr/Ca variability in a massive Porites lutea coral from the Lakshadweep Archipelago, Arabian Sea. The annual mean sea surface temperature (SST) in this region and the surrounding areas has increased steadily in the recent past. During some major El Niño events, SSTs are even higher, imposing additional thermal-stress on corals, episodically leading to coral bleaching. We infer from the coral-Sr/Ca record (1981-2008) that during some of these events high and persistent SSTs lead to a dampening of the temperature signal in coral-Sr/Ca, impairing the coral's ability to record full scale warming. Thus, coral-Sr/Ca may provide a history of past El Niño Southern-Oscillation (ENSO) induced thermal-stress episodes, which are a recurrent feature also seen in cross-spectral analysis between coral-Sr/Ca and the Nino3.4 index. Despite the impact of episodical thermal-stress during major El Niño events, our coral proxy faithfully records the seasonal monsoon-induced summer cooling on the order of ˜2.3°C. Calibration of coral-Sr/Ca with instrumental grid-SST data shows significant correlation to regional SST and monsoon variability. Hence, massive Porites corals of this region are highly valuable archives for reconstructing long-term changes in SST, strongly influenced by monsoon variability on seasonal scales. More importantly, our data show that this site with increasing SST is an ideal location for testing the future effects of the projected anthropogenic SST increase on coral reefs that are already under thermal-stress worldwide.

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

    PubMed Central

    van Woesik, Kelly; van Woesik, Liana; van Woesik, Sandra

    2013-01-01

    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. PMID:24282670

  5. Carbon and nitrogen cycling in the Zhubi coral reef lagoon of the South China Sea as revealed by 210Po and 210Pb.

    PubMed

    Yang, W F; Huang, Y P; Chen, M; Qiu, Y S; Li, H B; Zhang, L

    2011-05-01

    The radionuclides (210)Po and (210)Pb were examined to trace the cycling of particulate organic carbon (POC) and particulate organic nitrogen (PON) in the Zhubi coral reef lagoon. The net export flux of POC to the open sea is 14 mg Cm(-2) d(-1). However, the net exchange of PON has not yet been observed. On average, the vertical export fluxes in the lagoon of POC and PON, as derived from (210)Po/(210)Pb disequilibria, are 43 mg Cm(-2) d(-1) and 13.8 mg Nm(-2) d(-1), respectively. The deficit of (210)Po relative to (210)Pb in particulate matter provides evidence for the degradation of particulate organic matter. According to the mass balance budgets, 310 mg Cm(-2) d(-1) and 121 mg Nm(-2) d(-1) were recycled into dissolved fractions. Based on a first-order kinetics model, the degradation rate constants of POC and PON are 0.28 and 0.30 m(-1), respectively. Thus, (210)Po and (210)Pb can quantify the cycling of carbon and nitrogen in this coral lagoon.

  6. Coral Reefs: An English Compilation of Activities for Middle School Students.

    ERIC Educational Resources Information Center

    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…

  7. Spatial Scales of Bacterial Diversity in Cold-Water Coral Reef Ecosystems

    PubMed Central

    Schöttner, Sandra; Wild, Christian; Hoffmann, Friederike; Boetius, Antje; Ramette, Alban

    2012-01-01

    Background Cold-water coral reef ecosystems are recognized as biodiversity hotspots in the deep sea, but insights into their associated bacterial communities are still limited. Deciphering principle patterns of bacterial community variation over multiple spatial scales may however prove critical for a better understanding of factors contributing to cold-water coral reef stability and functioning. Methodology/Principal Findings Bacterial community structure, as determined by Automated Ribosomal Intergenic Spacer Analysis (ARISA), was investigated with respect to (i) microbial habitat type and (ii) coral species and color, as well as the three spatial components (iii) geomorphologic reef zoning, (iv) reef boundary, and (v) reef location. Communities revealed fundamental differences between coral-generated (branch surface, mucus) and ambient microbial habitats (seawater, sediments). This habitat specificity appeared pivotal for determining bacterial community shifts over all other study levels investigated. Coral-derived surfaces showed species-specific patterns, differing significantly between Lophelia pertusa and Madrepora oculata, but not between L. pertusa color types. Within the reef center, no community distinction corresponded to geomorphologic reef zoning for both coral-generated and ambient microbial habitats. Beyond the reef center, however, bacterial communities varied considerably from local to regional scales, with marked shifts toward the reef periphery as well as between different in- and offshore reef sites, suggesting significant biogeographic imprinting but weak microbe-host specificity. Conclusions/Significance This study presents the first multi-scale survey of bacterial diversity in cold-water coral reefs, spanning a total of five observational levels including three spatial scales. It demonstrates that bacterial communities in cold-water coral reefs are structured by multiple factors acting at different spatial scales, which has fundamental

  8. The giant oyster Hyotissa hyotis from the northern Red Sea as a decadal-scale archive for seasonal environmental fluctuations in coral reef habitats

    NASA Astrophysics Data System (ADS)

    Titschack, J.; Zuschin, M.; Spötl, C.; Baal, C.

    2010-12-01

    This study explores the giant oyster Hyotissa hyotis as a novel environmental archive in tropical reef environments of the Indo-Pacific. The species is a typical accessory component in coral reefs, can reach sizes of tens of centimetres, and dates back to the Late Pleistocene. Here, a 70.2-mm-long oxygen and carbon isotope transect through the shell of a specimen collected at Safaga Bay, northern Red Sea, in May 1996, is presented. The transect runs perpendicularly to the foliate and vesicular layers of the inner ostracum near the ligament area of the oyster. The measured δ18O and δ13C records show sinusoidal fluctuations, which are independent of shell microstructure. The δ13C fluctuations exhibit the same wavelength as the δ18O fluctuations but are phase shifted. The δ18O record reflects the sea surface temperature variations from 1957 until 1996, possibly additionally influenced by the local evaporation. Due to locally enhanced evaporation in the semi-enclosed Safaga Bay, the δ18Oseawater value is estimated at 2.17‰, i.e., 0.3-0.8‰ higher than published open surface water δ18O values (1.36-1.85‰) from the region. The mean water temperature deviates by only 0.4°C from the expected value, and the minimum and maximum values are 0.5°C lower and 2.9°C higher, respectively. When comparing the mean monthly values, however, the sea surface temperature discrepancy between reconstructed and global grid datasets is always <1.0°C. The δ13C signal is weakly negatively correlated with regional chlorophyll a concentration and with the sunshine duration, which may reflect changes in the bivalve’s respiration. The study emphasises the palaeogeographic context in isotope studies based on fossils, because coastal embayments might not reflect open-water oceanographic conditions.

  9. A 200-Year Record of Interannual SST and pH Variability from the Lesser Antilles (Caribbean Sea, North Atlantic) Inferred from a Siderastrea Siderea Reef Coral

    NASA Astrophysics Data System (ADS)

    Douville, E.; Paterne, M.; Feuillet, N.; Noury, C.; Bordier, L.; Thil, F.

    2014-12-01

    Global warming and ocean acidification caused by the rising levels of anthropogenic CO2 in the atmosphere need to be better constrained by long-term studies of high resolution natural archives, especially at inter-annual and decadal scales. In the framework of the French INSU program LEFE/CYBER ACID-Antilles, here we developed a 200-year long interannual time series of sea surface temperature and pH based on the geochemical composition of tropical reef forming coral. The selected tropical coral called CHANCEL-1 is a colony of genus Siderastrea Siderea which was collected in 2008 from a living micro-atoll off Martinique in the Lesser Antilles, facing the eastern side of the Caribbean Sea. The colony of 1-meter extension presents a mean growth rate of 4 - 5 mm/yr. Along the growth axis, we measured the boron isotopic composition (delta11B) and trace element ratios (Li/Mg, Sr/Ca), which reveal a progressive decrease of the surface water pH and increase of temperature during the past 200 years. These observations cooperate the anthropogenic forcing, i.e. rising atmospheric CO2 and rising sea surface temperatures due to global warming. However, other processes apparently affect the geochemical records, as indicated by sub-decadal variations of pH and temperature reconstruction overprinting the long term global trend. Possible drivers of such most likely regional variability might be decadal changes of oceanographic conditions (upwelling, freshwater runoff, seawater masse changes, etc.) as well as species dependent biological controls.

  10. The Global Coral Reef Crisis: Trends and Solutions (Coral Reefs: Values, Threats, and the Marine Aquarium Trade)

    SciTech Connect

    Shuman, Craig S.

    2003-02-05

    Second only to tropical rainforests, coral reefs support one of the world's most diverse natural habitats. Over 350 million individuals depend on coral reef resources for food and income. Unfortunately, the Earth is in the midst of a coral reef crisis. Anthropogenic impacts including overfishing, destructive fishing practices, sedimentation and pollution, as well as global climate change, have served to disrupt the natural processes that maintain the health of these ecosystems. Until recently, however, the global extent of the coral reef crisis was unknown. Reef Check was developed in 1996 as a volunteer, community-based monitoring protocol designed to measure the health of coral reefs on a global scale. With goals of education, monitoring, and management, Reef Check has activities in over 60 countries and territories. They have not only provided scientific evidence of the global extent of the coral reef crisis, but have provided the first community based steps to alleviate this urgent situation.

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

    PubMed

    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.

  12. Fishing degrades size structure of coral reef fish communities.

    PubMed

    Robinson, James P W; Williams, Ivor D; Edwards, Andrew M; McPherson, Jana; Yeager, Lauren; Vigliola, Laurent; Brainard, Russell E; Baum, Julia K

    2017-03-01

    Fishing pressure on coral reef ecosystems has been frequently linked to reductions of large fishes and reef fish biomass. Associated impacts on overall community structure are, however, less clear. In size-structured aquatic ecosystems, fishing impacts are commonly quantified using size spectra, which describe the distribution of individual body sizes within a community. We examined the size spectra and biomass of coral reef fish communities at 38 US-affiliated Pacific islands that ranged in human presence from near pristine to human population centers. Size spectra 'steepened' steadily with increasing human population and proximity to market due to a reduction in the relative biomass of large fishes and an increase in the dominance of small fishes. Reef fish biomass was substantially lower on inhabited islands than uninhabited ones, even at inhabited islands with the lowest levels of human presence. We found that on populated islands size spectra exponents decreased (analogous to size spectra steepening) linearly with declining biomass, whereas on uninhabited islands there was no relationship. Size spectra were steeper in regions of low sea surface temperature but were insensitive to variation in other environmental and geomorphic covariates. In contrast, reef fish biomass was highly sensitive to oceanographic conditions, being influenced by both oceanic productivity and sea surface temperature. Our results suggest that community size structure may be a more robust indicator than fish biomass to increasing human presence and that size spectra are reliable indicators of exploitation impacts across regions of different fish community compositions, environmental drivers, and fisheries types. Size-based approaches that link directly to functional properties of fish communities, and are relatively insensitive to abiotic variation across biogeographic regions, offer great potential for developing our understanding of fishing impacts in coral reef ecosystems.

  13. Geographic extent and variation of a coral reef trophic cascade.

    PubMed

    McClanahan, T R; Muthiga, N A

    2016-07-01

    Trophic cascades caused by a reduction in predators of sea urchins have been reported in Indian Ocean and Caribbean coral reefs. Previous studies have been constrained by their site-specific nature and limited spatial replication, which has produced site and species-specific understanding that can potentially preclude larger community-organization nuances and generalizations. In this study, we aimed to evaluate the extent and variability of the cascade community in response to fishing across ~23° of latitude and longitude in coral reefs in the southwestern Indian Ocean. The taxonomic composition of predators of sea urchins, the sea urchin community itself, and potential effects of changing grazer abundance on the calcifying benthic organisms were studied in 171 unique coral reef sites. We found that geography and habitat were less important than the predator-prey relationships. There were seven sea urchin community clusters that aligned with a gradient of declining fishable biomass and the abundance of a key predator, the orange-lined triggerfish (Balistapus undulatus). The orange-lined triggerfish dominated where sea urchin numbers and diversity were low but the relative abundance of wrasses and emperors increased where sea urchin numbers were high. Two-thirds of the study sites had high sea urchin biomass (>2,300 kg/ha) and could be dominated by four different sea urchin species, Echinothrix diadema, Diadema savignyi, D. setosum, and Echinometra mathaei, depending on the community of sea urchin predators, geographic location, and water depth. One-third of the sites had low sea urchin biomass and diversity and were typified by high fish biomass, predators of sea urchins, and herbivore abundance, representing lightly fished communities with generally higher cover of calcifying algae. Calcifying algal cover was associated with low urchin abundance where as noncalcifying fleshy algal cover was not clearly associated with herbivore abundance. Fishing of the orange

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

    NASA Astrophysics Data System (ADS)

    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

  15. GLOBAL CHANGE EFFECTS ON CORAL REEF CONDITION

    EPA Science Inventory

    Fisher, W., W. Davis, J. Campbell, L. Courtney, P. Harris, B. Hemmer, M. Parsons, B. Quarles and D. Santavy. In press. Global Change Effects on Coral Reef Condition (Abstract). To be presented at the EPA Science Forum: Healthy Communities and Ecosystems, 1-3 June 2004, Washington...

  16. Water Quality Standards for Coral Reef Protection

    EPA Science Inventory

    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...

  17. Fishing down nutrients on coral reefs

    PubMed Central

    Allgeier, Jacob E.; Valdivia, Abel; Cox, Courtney; Layman, Craig A.

    2016-01-01

    Fishing is widely considered a leading cause of biodiversity loss in marine environments, but the potential effect on ecosystem processes, such as nutrient fluxes, is less explored. Here, we test how fishing on Caribbean coral reefs influences biodiversity and ecosystem functions provided by the fish community, that is, fish-mediated nutrient capacity. Specifically, we modelled five processes of nutrient storage (in biomass) and supply (via excretion) of nutrients, as well as a measure of their multifunctionality, onto 143 species of coral reef fishes across 110 coral reef fish communities. These communities span a gradient from extreme fishing pressure to protected areas with little to no fishing. We find that in fished sites fish-mediated nutrient capacity is reduced almost 50%, despite no substantial changes in the number of species. Instead, changes in community size and trophic structure were the primary cause of shifts in ecosystem function. These findings suggest that a broader perspective that incorporates predictable impacts of fishing pressure on ecosystem function is imperative for effective coral reef conservation and management. PMID:27529748

  18. Fishing down nutrients on coral reefs.

    PubMed

    Allgeier, Jacob E; Valdivia, Abel; Cox, Courtney; Layman, Craig A

    2016-08-16

    Fishing is widely considered a leading cause of biodiversity loss in marine environments, but the potential effect on ecosystem processes, such as nutrient fluxes, is less explored. Here, we test how fishing on Caribbean coral reefs influences biodiversity and ecosystem functions provided by the fish community, that is, fish-mediated nutrient capacity. Specifically, we modelled five processes of nutrient storage (in biomass) and supply (via excretion) of nutrients, as well as a measure of their multifunctionality, onto 143 species of coral reef fishes across 110 coral reef fish communities. These communities span a gradient from extreme fishing pressure to protected areas with little to no fishing. We find that in fished sites fish-mediated nutrient capacity is reduced almost 50%, despite no substantial changes in the number of species. Instead, changes in community size and trophic structure were the primary cause of shifts in ecosystem function. These findings suggest that a broader perspective that incorporates predictable impacts of fishing pressure on ecosystem function is imperative for effective coral reef conservation and management.

  19. Fishing down nutrients on coral reefs

    NASA Astrophysics Data System (ADS)

    Allgeier, Jacob E.; Valdivia, Abel; Cox, Courtney; Layman, Craig A.

    2016-08-01

    Fishing is widely considered a leading cause of biodiversity loss in marine environments, but the potential effect on ecosystem processes, such as nutrient fluxes, is less explored. Here, we test how fishing on Caribbean coral reefs influences biodiversity and ecosystem functions provided by the fish community, that is, fish-mediated nutrient capacity. Specifically, we modelled five processes of nutrient storage (in biomass) and supply (via excretion) of nutrients, as well as a measure of their multifunctionality, onto 143 species of coral reef fishes across 110 coral reef fish communities. These communities span a gradient from extreme fishing pressure to protected areas with little to no fishing. We find that in fished sites fish-mediated nutrient capacity is reduced almost 50%, despite no substantial changes in the number of species. Instead, changes in community size and trophic structure were the primary cause of shifts in ecosystem function. These findings suggest that a broader perspective that incorporates predictable impacts of fishing pressure on ecosystem function is imperative for effective coral reef conservation and management.

  20. The influence of coral reefs and climate change on wave-driven flooding of tropical coastlines

    USGS Publications Warehouse

    Ellen Quataert,; Storlazzi, Curt; Arnold van Rooijen,; Ap van Dongeren,; Cheriton, Olivia

    2015-01-01

    A numerical model, XBeach, calibrated and validated on field data collected at Roi-Namur Island on Kwajalein Atoll in the Republic of Marshall Islands, was used to examine the effects of different coral reef characteristics on potential coastal hazards caused by wave-driven flooding and how these effects may be altered by projected climate change. The results presented herein suggest that coasts fronted by relatively narrow reefs with steep fore reef slopes (~1:10 and steeper) and deeper, smoother reef flats are expected to experience the highest wave runup. Wave runup increases for higher water levels (sea level rise), higher waves, and lower bed roughness (coral degradation), which are all expected effects of climate change. Rising sea levels and climate change will therefore have a significant negative impact on the ability of coral reefs to mitigate the effects of coastal hazards in the future.

  1. The influence of coral reefs and climate change on wave-driven flooding of tropical coastlines

    NASA Astrophysics Data System (ADS)

    Quataert, Ellen; Storlazzi, Curt; Rooijen, Arnold; Cheriton, Olivia; Dongeren, Ap

    2015-08-01

    A numerical model, XBeach, calibrated and validated on field data collected at Roi-Namur Island on Kwajalein Atoll in the Republic of Marshall Islands, was used to examine the effects of different coral reef characteristics on potential coastal hazards caused by wave-driven flooding and how these effects may be altered by projected climate change. The results presented herein suggest that coasts fronted by relatively narrow reefs with steep fore reef slopes (~1:10 and steeper) and deeper, smoother reef flats are expected to experience the highest wave runup. Wave runup increases for higher water levels (sea level rise), higher waves, and lower bed roughness (coral degradation), which are all expected effects of climate change. Rising sea levels and climate change will therefore have a significant negative impact on the ability of coral reefs to mitigate the effects of coastal hazards in the future.

  2. Climate change and coral reef connectivity

    NASA Astrophysics Data System (ADS)

    Munday, P. L.; Leis, J. M.; Lough, J. M.; Paris, C. B.; Kingsford, M. J.; Berumen, M. L.; Lambrechts, J.

    2009-06-01

    This review assesses and predicts the impacts that rapid climate change will have on population connectivity in coral reef ecosystems, using fishes as a model group. Increased ocean temperatures are expected to accelerate larval development, potentially leading to reduced pelagic durations and earlier reef-seeking behaviour. Depending on the spatial arrangement of reefs, the expectation would be a reduction in dispersal distances and the spatial scale of connectivity. Small increase in temperature might enhance the number of larvae surviving the pelagic phase, but larger increases are likely to reduce reproductive output and increase larval mortality. Changes to ocean currents could alter the dynamics of larval supply and changes to planktonic productivity could affect how many larvae survive the pelagic stage and their condition at settlement; however, these patterns are likely to vary greatly from place-to-place and projections of how oceanographic features will change in the future lack sufficient certainty and resolution to make robust predictions. Connectivity could also be compromised by the increased fragmentation of reef habitat due to the effects of coral bleaching and ocean acidification. Changes to the spatial and temporal scales of connectivity have implications for the management of coral reef ecosystems, especially the design and placement of marine-protected areas. The size and spacing of protected areas may need to be strategically adjusted if reserve networks are to retain their efficacy in the future.

  3. Can coral reefs be monitored from space?

    PubMed

    Philipson, Petra; Lindell, Tommy

    2003-12-01

    The dramatic bleaching events on the coral reefs recently have enhanced the need for environmental monitoring. Remote sensing is an important constituent for monitoring of reefs, and an invaluable complement to field observations. This paper discusses the possibilities and limitations of present high resolution satellites for mapping and monitoring coral reefs. The sensors with the best spatial and radiometric resolution available today, e.g. IKONOS, can be useful for mapping and monitoring of reefs, but they are too costly for global surveys. However, our coral bleaching studies indicate that massive bleaching could be detected even from satellites with lower resolution, like Landsat, SPOT, and IRS. They could also be useful for coarser, from a spatial and thematic point of view, global mapping and updating purposes. A more detailed monitoring requires both better spatial resolution and spectral resolution than today's sensors. In the future, it is necessary to construct a more reef specific sensor with a few specially selected narrow bands and a good spatial, radiometric and temporal resolution.

  4. Decadal coral community reassembly on an African fringing reef

    NASA Astrophysics Data System (ADS)

    McClanahan, T. R.

    2014-12-01

    Changes in the cover of the dominant hard coral taxa were studied on seven Kenyan back reefs over 20 yr. All factors of time, taxa, site, and their interactions were statistically significant and the 1998 temperature anomaly caused the greatest community changes. The 1998 disturbance changes reflected a classic coral succession, which included partial or little mortality and persistence of stress tolerant (massive and submassive growth forms) and early colonization by weedy taxa (pocilloporids). Nevertheless, competitive taxa had high and full mortality and the expected dominance of acroporids was inhibited even ~13 yr after the disturbance. So, while total hard coral cover displayed the expected logistic recovery where maximum cover was reached <10 yr after the disturbance, the poor recovery of competitive dominants resulted in less than expected coral cover. A number of stress-resistant and weedy taxa (poritids, agaricidae, faviids, and pocilloporids) are expected to dominate the composition of these reefs in the future. Nevertheless, three submassive faviids and branching Porites began to decline toward the end of the time series, indicating further stress after 1998. Increased algal cover and other unstudied factors, including milder warming, may explain these changes. The patterns of change on this continental fringing reef differ from recovery of more remote, offshore islands. This probably reflects low acroporid dominance and recruitment limitations associated with greater anthropogenic influences of high sea urchin grazing and terrestrial runoff.

  5. Geochemical consequences of increased atmospheric carbon dioxide on coral reefs

    USGS Publications Warehouse

    Kleypas, J.A.; Buddemeier, R.W.; Archer, D.; Gattuso, J.-P.; Langdon, C.; Opdyke, B.N.

    1999-01-01

    A coral reef represents the net accumulation of calcium carbonate (CaCO3) produced by corals and other calcifying organisms. If calcification declines, then reef-building capacity also declines. Coral reef calcification depends on the saturation state of the carbonate mineral aragonite of surface waters. By the middle of the next century, an increased concentration of carbon dioxide will decrease the aragonite saturation state in the tropics by 30 percent and biogenic aragonite precipitation by 14 to 30 percent. Coral reefs are particularly threatened, because reef-building organisms secrete metastable forms of CaCO3, but the biogeochemical consequences on other calcifying marine ecosystems may be equally severe.

  6. Facies and environmental setting of the Miocene coral reefs in the late-orogenic fill of the Antalya Basin, western Taurides, Turkey: implications for tectonic control and sea-level changes

    NASA Astrophysics Data System (ADS)

    Karabıyıkoğlu, M.; Tuzcu, S.; Çiner, A.; Deynoux, M.; Örçen, S.; Hakyemez, A.

    2005-01-01

    prüçay sub-basins. The Late Miocene reefs occur only in the Aksu sub-basin and are characterized by low-diversity hermatypic corals exclusively dominated by Porites and Tarbelastraea with minor Siderastraea, Favites and Platygyra. They developed on alluvial fan/fan-delta complexes and shallow marine shelf carbonates. The Miocene coral reef growth and development in the Antalya Basin are characterized by large- to small-scale, transgressive-regressive reefal cycles which are closely related to the complex interaction of sporadic influxes of coarse terrigeneous clastics derived from the tectonically active basin margins and the related sea-level fluctuations.

  7. An observational heat budget analysis of a coral reef, Heron Reef, Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    MacKellar, Mellissa C.; McGowan, Hamish A.; Phinn, Stuart R.

    2013-03-01

    Measurements of the surface energy balance, the structure and evolution of the convective atmospheric reef layer (CARL), and local meteorology and hydrodynamics were made during June 2009 and February 2010 at Heron Reef, Australia, to establish the relative partitioning of heating within the water and atmosphere. Horizontal advection was shown to moderate temperature in the CARL and the water, having a cooling influence on the atmosphere, and providing an additional source or sink of energy to the water overlying the reef, depending on tide. The key driver of atmospheric heating was surface sensible heat flux, while heating of the reef water was primarily due to solar radiation, and thermal conduction and convection from the reef substrate. Heating and cooling processes were more defined during winter due to higher sensible and latent heat fluxes and strong diurnal evolution of the CARL. Sudden increases in water temperature were associated with inundation of warmer oceanic water during the flood tide, particularly in winter due to enhanced nocturnal cooling of water overlying the reef. Similarly, cooling of the water over the reef occurred during the ebb tide as heat was transported off the reef to the surrounding ocean. While these results are the first to shed light on the heat budget of a coral reef and overlying CARL, longer-term, systematic measurements of reef thermal budgets are needed under a range of meteorological and hydrodynamic conditions, and across various reef types to elucidate the influence on larger-scale oceanic and atmospheric processes. This is essential for understanding the role of coral reefs in tropical and sub-tropical meteorology; the physical processes that take place during coral bleaching events, and coral and algal community dynamics on coral reefs.

  8. Density-associated recruitment mediates coral population dynamics on a coral reef

    NASA Astrophysics Data System (ADS)

    Bramanti, Lorenzo; Edmunds, Peter J.

    2016-06-01

    Theory suggests that density-associated processes can modulate community resilience following declines in population size. Here, we demonstrate density-associated processes in two scleractinian populations on the outer reef of Moorea, French Polynesia, that are rapidly increasing in size following the effects of two catastrophic disturbances. Between 2006 and 2010, predation by the corallivorous crown-of-thorns sea star reduced coral cover by 93 %; in 2010, the dead coral skeletons were removed by a cyclone, and in 2011 and 2012, high coral recruitment initiated population recovery. Coral recruitment was associated with coral cover, but the relationship differed between two coral genera that are almost exclusively broadcast spawners in Moorea. Acroporids recruited at low densities, and the density of recruits was positively associated with cover of Acropora, whereas pocilloporids recruited at high densities, and densities of their recruits were negatively associated with cover of Pocillopora. Together, our results suggest that associations between adult cover and density of both juveniles and recruits can mediate rapid coral community recovery after large disturbances. The difference between taxa in sign of the relationships between recruit density and coral cover indicate that they reflect contrasting mechanisms with the potential to mediate temporal shifts in taxonomic composition of coral communities.

  9. Coral identity underpins architectural complexity on Caribbean reefs.

    PubMed

    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.

  10. Coral Reef Education and Australian High School Students

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2004-01-01

    Educational programs that focus on humans and their relationship to coral reefs are becoming necessary, as reef structures along the Queensland coast come under mounting ecological pressure. This paper reports on a PhD research project which investigated marine education and learning with high school students in coral reef environments along the…

  11. 75 FR 21650 - Coral Reef Restoration Plan, Draft Programmatic Environmental Impact Statement, Biscayne National...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-26

    ... National Park Service Coral Reef Restoration Plan, Draft Programmatic Environmental Impact Statement... Availability of the Draft Programmatic Environmental Impact Statement for the Coral Reef Restoration Plan... Environmental Impact Statement (DEIS) for the Coral Reef Restoration Plan for Biscayne National Park,...

  12. Key Ecological Interactions of Reef Building Corals - 11-16-2011

    EPA Science Inventory

    Coral reefs are very important marine ecosystems because they support tremendous biodiversity and reefs are critical economic resources many coastal nations. Tropical reef structures are largely built by stony corals. This presentation provides background on basic coral biology t...

  13. Coral reef metabolism and carbon chemistry dynamics of a coral reef flat

    NASA Astrophysics Data System (ADS)

    Albright, Rebecca; Benthuysen, Jessica; Cantin, Neal; Caldeira, Ken; Anthony, Ken

    2015-05-01

    Global carbon emissions continue to acidify the oceans, motivating growing concern for the ability of coral reefs to maintain net positive calcification rates. Efforts to develop robust relationships between coral reef calcification and carbonate parameters such as aragonite saturation state (Ωarag) aim to facilitate meaningful predictions of how reef calcification will change in the face of ocean acidification. Here we investigate natural trends in carbonate chemistry of a coral reef flat over diel cycles and relate these trends to benthic carbon fluxes by quantifying net community calcification and net community production. We find that, despite an apparent dependence of calcification on Ωarag seen in a simple pairwise relationship, if the dependence of net calcification on net photosynthesis is accounted for, knowing Ωarag does not add substantial explanatory value. This suggests that, over short time scales, the control of Ωarag on net calcification is weak relative to factors governing net photosynthesis.

  14. Subaerially exposed Holocene coral reef, Enriquillo Valley, Dominican Republic

    NASA Technical Reports Server (NTRS)

    Mann, P.; Taylor, F. W.; Burke, K.; Kulstad, R.

    1984-01-01

    An extremely well-preserved Holocene fringing coral reef occurs at an average elevation of 5 m below sea level around the margins of the central Enriquillo Valley, Dominican Republic. The reef records the latest marine incursion from the east into an 85-km-long, 12-km-wide tectonic depression and appears to represent a unique preservation. Excellent cross sections of the reef exposed in erosional gullies reveal a composition and zonation typical of modern Caribbean reefs that are found in offshore low-energy environments. Radiocarbon age determinations (2) indicate that reef growth coincided with sea-level rise following the last ice age (5,930 + or - 100 to 4,760 + or - 90 yr B.P.). Deltaic deposition and possible vertical movements on active fault scarps dammed the eastern mouth of the valley and created Lago Enriquillo, the level of which was then rapidly lowered by evaporation in an arid climate to produce a saline lake approximately 40 m below sea level. Stratigraphic studies of rocks along the valley edge and data from drill holes in the basin center indicate that there were earlier post-Miocene marine incursions similar to that described here.

  15. Rapid transition in the structure of a coral reef community: the effects of coral bleaching and physical disturbance.

    PubMed

    Ostrander, G K; Armstrong, K M; Knobbe, E T; Gerace, D; Scully, E P

    2000-05-09

    Coral reef communities are in a state of change throughout their geographical range. Factors contributing to this change include bleaching (the loss of algal symbionts), storm damage, disease, and increasing abundance of macroalgae. An additional factor for Caribbean reefs is the aftereffects of the epizootic that reduced the abundance of the herbivorous sea urchin, Diadema antillarum. Although coral reef communities have undergone phase shifts, there are few studies that document the details of such transitions. We report the results of a 40-month study that documents changes in a Caribbean reef community affected by bleaching, hurricane damage, and an increasing abundance of macroalgae. The study site was in a relatively pristine area of the reef surrounding the island of San Salvador in the Bahamas. Ten transects were sampled every 3-9 months from November 1994 to February 1998. During this period, the corals experienced a massive bleaching event resulting in a significant decline in coral abundance. Algae, especially macroalgae, increased in abundance until they effectively dominated the substrate. The direct impact of Hurricane Lili in October 1996 did not alter the developing community structure and may have facilitated increasing algal abundance. The results of this study document the rapid transition of this reef community from one in which corals and algae were codominant to a community dominated by macroalgae. The relatively brief time period required for this transition illustrates the dynamic nature of reef communities.

  16. Climate-driven coral reorganisation influences aggressive behaviour in juvenile coral-reef fishes

    NASA Astrophysics Data System (ADS)

    Kok, Judith E.; Graham, Nicholas A. J.; Hoogenboom, Mia O.

    2016-06-01

    Globally, habitat degradation is altering the abundance and diversity of species in a variety of ecosystems. This study aimed to determine how habitat degradation, in terms of changing coral composition under climate change, affected abundance, species richness and aggressive behaviour of juveniles of three damselfishes ( Pomacentrus moluccensis, P. amboinensis and Dischistodus perspicillatus, in order of decreasing reliance on coral). Patch reefs were constructed to simulate two types of reefs: present-day reefs that are vulnerable to climate-induced coral bleaching, and reefs with more bleaching-robust coral taxa, thereby simulating the likely future of coral reefs under a warming climate. Fish communities were allowed to establish naturally on the reefs during the summer recruitment period. Climate-robust reefs had lower total species richness of coral-reef fishes than climate-vulnerable reefs, but total fish abundance was not significantly different between reef types (pooled across all species and life-history stages). The nature of aggressive interactions, measured as the number of aggressive chases, varied according to coral composition; on climate-robust reefs, juveniles used the substratum less often to avoid aggression from competitors, and interspecific aggression became relatively more frequent than intraspecific aggression for juveniles of the coral-obligate P. moluccensis. This study highlights the importance of coral composition as a determinant of behaviour and diversity of coral-reef fishes.

  17. Fine sediments suppress detritivory on coral reefs.

    PubMed

    Tebbett, Sterling B; Goatley, Christopher H R; Bellwood, David R

    2017-01-30

    Increasing sediment inputs are recognised as an important factor leading to coral reef degradation. However, the role of sediments in ecological processes is poorly understood. This study used paired-choice trials to quantify the effects of sediment grain size and chemical composition on feeding by the abundant detritivorous reef fish, Ctenochaetus striatus. The size of sediments from algal turfs were also compared to those ingested by reef-dwelling C. striatus. Algal turfs containing coarser sediments were preferred by C. striatus, while sediment composition (reefal carbonates vs. riverine silicates) had little effect. On the reef, C. striatus ingested finer sediments than those present in algal turfs. C. striatus appears to prefer algal turfs with coarser sediments as this facilitates ingestion of fine detrital particles, while finer sediments prevent selective feeding on detritus. These findings suggest that fine sediments from terrestrial runoff or dredging may be detrimental to feeding by detritivorous species.

  18. The geological effects of hurricanes on coral reefs and the interpretation of storm deposits

    NASA Astrophysics Data System (ADS)

    Scoffin, T. P.

    1993-11-01

    Hurricanes occur in belts 7° to 25° north and south of the equator. Reefs growing in these belts suffer periodic damage from hurricane-generated waves and storm surge. Corals down to 20m depth may be broken and removed, branching colonies being much more susceptible to breakage than upright massive forms. Sand cays may be washed away and former storm ridges may migrate to leeward across reef flats to link with islands. Reef crest and reef front coral debris accumulate as talus at the foot of the fore-reef slope, on submarine terraces and grooves, on the intertidal reef flat as storm ridges of shingle or boulders and isolated blocks of reef framework, as accreting beach ridges of leeward migrating shingle, as lobes and wedges of debris in back-reef lagoons, as drapes of carbonate sand and mud in deep off-reef locations in the fore-reef and lagoonal areas. In addition to the coarse debris deposited, other features may aid the recognition of former hurricane events, including the assemblage of reef biota, its species composition and the structure of the skeletons; graded internal sediments in framework cavities; characteristic sequences of encrusting organisms; characteristic shapes of reef flat microatoll corals; and submarine cement crusts over truncated reef surfaces. The abundance of reef flat storm deposits whose ages cluster around 3000 4000 y BP in certain parts of the world most likely relate to a slight fall in relative sea level rather than an increase in storminess during that period. A higher frequency of storms need not result in more reef flat storm deposits. The violence of the storm relative to normal fair-weather conditions influences the extent of damage; the length of time since the previous major storm influences the amount of coral debris created; the length of time after the hurricane, and before a subsequent storm influences the degree of stabilization of reef-top storm deposits and hence their chances of preservation.

  19. Current and future sustainability of island coral reef fisheries.

    PubMed

    Newton, Katie; Côté, Isabelle M; Pilling, Graham M; Jennings, Simon; Dulvy, Nicholas K

    2007-04-03

    Overexploitation is one of the principal threats to coral reef diversity, structure, function, and resilience [1, 2]. Although it is generally held that coral reef fisheries are unsustainable [3-5], little is known of the overall scale of exploitation or which reefs are overfished [6]. Here, on the basis of ecological footprints and a review of exploitation status [7, 8], we report widespread unsustainability of island coral reef fisheries. Over half (55%) of the 49 island countries considered are exploiting their coral reef fisheries in an unsustainable way. We estimate that total landings of coral reef fisheries are currently 64% higher than can be sustained. Consequently, the area of coral reef appropriated by fisheries exceeds the available effective area by approximately 75,000 km(2), or 3.7 times the area of Australia's Great Barrier Reef, and an extra 196,000 km(2) of coral reef may be required by 2050 to support the anticipated growth in human populations. The large overall imbalance between current and sustainable catches implies that management methods to reduce social and economic dependence on reef fisheries are essential to prevent the collapse of coral reef ecosystems while sustaining the well-being of burgeoning coastal populations.

  20. The role of coral reef rugosity in dissipating wave energy and coastal protection

    NASA Astrophysics Data System (ADS)

    Harris, Daniel; Rovere, Alessio; Parravicini, Valeriano; Casella, Elisa

    2016-04-01

    Coral reefs are the most effective natural barrier in dissipating wave energy through breaking and bed friction. The attenuation of wave energy by coral reef flats is essential in the protection and stability of coral reef aligned coasts and reef islands. However, the effectiveness of wave energy dissipation by coral reefs may be diminished under future climate change scenarios with a potential reduction of coral reef rugosity due to increased stress environmental stress on corals. The physical roughness or rugosity of coral reefs is directly related to ecological diversity, reef health, and hydrodynamic roughness. However, the relationship between physical roughness and hydrodynamic roughness is not well understood despite the crucial role of bed friction in dissipating wave energy in coral reef aligned coasts. We examine the relationship between wave energy dissipation across a fringing reef in relation to the cross-reef ecological zonation and the benthic hydrodynamic roughness. Waves were measured by pressure transducers in a cross-reef transect on the reefs flats and post processed on a wave by wave basis to determine wave statistics such as significant wave height and wave period. Results from direct wave measurement were then used to calibrate a 1D wave dissipation model that incorporates dissipation functions due to bed friction and wave breaking. This model was used to assess the bed roughness required to produce the observed wave height dissipation during propagation from deep water and across the coral reef flats. Changes in wave dissipation was also examined under future scenarios of sea level rise and reduced bed roughness. Three dimensional models of the benthic reef structure were produced through structure-from-motion photogrammetry surveys. Reef rugosity was then determined from these surveys and related to the roughness results from the calibrated model. The results indicate that applying varying roughness coefficients as the benthic ecological

  1. Vertical variations of coral reef drag forces

    NASA Astrophysics Data System (ADS)

    Asher, Shai; Niewerth, Stephan; Koll, Katinka; Shavit, Uri

    2016-05-01

    Modeling flow in a coral reef requires a closure model that links the local drag force to the local mean velocity. However, the spatial flow variations make it difficult to predict the distribution of the local drag. Here we report on vertical profiles of measured drag and velocity in a laboratory reef that was made of 81 Pocillopora Meandrina colony skeletons, densely arranged along a tilted flume. Two corals were CT-scanned, sliced horizontally, and printed using a 3-D printer. Drag was measured as a function of height above the bottom by connecting the slices to drag sensors. Profiles of velocity were measured in-between the coral branches and above the reef. Measured drag of whole colonies shows an excellent agreement with previous field and laboratory studies; however, these studies never showed how drag varies vertically. The vertical distribution of drag is reported as a function of flow rate and water level. When the water level is the same as the reef height, Reynolds stresses are negligible and the drag force per unit fluid mass is nearly constant. However, when the water depth is larger, Reynolds stress gradients become significant and drag increases with height. An excellent agreement was found between the drag calculated by a momentum budget and the measured drag of the individual printed slices. Finally, we propose a modified formulation of the drag coefficient that includes the normal dispersive stress term and results in reduced variations of the drag coefficient at the cost of introducing an additional coefficient.

  2. 76 FR 82413 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ... Part 622 Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants... Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and... FMP), and Amendment 3 to the FMP for Corals and Reef Associated Plants and Invertebrates of...

  3. The effect of coral morphology on shelter selection by coral reef fishes

    NASA Astrophysics Data System (ADS)

    Kerry, J. T.; Bellwood, D. R.

    2012-06-01

    While the loss of structural complexity causes declines in coral reef fish diversity, the processes leading to this decline are largely unexplained. To explore the role of coral morphology in providing shelter for fishes, tabular, branching and massive corals were filmed with video cameras and their usage by large reef fishes compared. Tabular corals were utilised more than the other two morphologies, with at least triple the abundance, biomass and residence times of large fishes. The preference of coral reef fishes for specific structural traits of tabular corals was also examined using artificial structural units. This experimental component showed that large reef fishes preferred opaque rather than translucent canopies. It appears that large fishes cue to tabular corals because of the concealment and/or shade provided. It is suggested that a loss of tabular corals as a result of climate change would have significant ecological impacts for the coral reef fishes that use these structures for shelter.

  4. Monitoring of coastal coral reefs near Dahab (Gulf of Aqaba, Red Sea) indicates local eutrophication as potential cause for change in benthic communities.

    PubMed

    Naumann, Malik S; Bednarz, Vanessa N; Ferse, Sebastian C A; Niggl, Wolfgang; Wild, Christian

    2015-02-01

    Coral reef ecosystems fringing the coastline of Dahab (South Sinai, Egypt) have experienced increasing anthropogenic disturbance as an emergent international tourism destination. Previous reports covering tourism-related impacts on coastal environments, particularly mechanical damage and destructive fishing, have highlighted the vital necessity for regular ecosystem monitoring of coral reefs near Dahab. However, a continuous scientific monitoring programme of permanent survey sites has not been established to date. Thus, this study conducted in situ monitoring surveys to investigate spatio-temporal variability of benthic reef communities and selected reef-associated herbivores along with reef health indicator organisms by revisiting three of the locally most frequented dive sites during expeditions in March 2010, September 2011 and February 2013. In addition, inorganic nutrient concentrations in reef-surrounding waters were determined to evaluate bottom-up effects of key environmental parameters on benthic reef community shifts in relation to grazer-induced top-down control. Findings revealed that from 2010 to 2013, live hard coral cover declined significantly by 12 % at the current-sheltered site Three Pools (TP), while showing negative trends for the Blue Hole (BH) and Lighthouse (LH) sites. Hard coral cover decline was significantly and highly correlated to a substantial increase in turf algae cover (up to 57 % at TP) at all sites, replacing hard corals as dominant benthic space occupiers in 2013. These changes were correlated to ambient phosphate and ammonium concentrations that exhibited highest values (0.64 ± 0.07 μmol PO4 (3-) l(-1), 1.05 ± 0.07 μmol NH4 (+) l(-1)) at the degraded site TP. While macroalgae appeared to respond to both bottom-up and top-down factors, change in turf algae was consistent with expected indications for bottom-up control. Temporal variability measured in herbivorous reef fish stocks reflected seasonal impacts by

  5. Evaluation of Stony Coral Indicators for Coral Reef ...

    EPA Pesticide Factsheets

    Colonies of reef-building stony corals at 57 stations around St. Croix, U.S. Virgin Islands were characterized by species, size and percentage of living tissue. Taxonomic, biological and physical indicators of coral condition were derived from these measurements and assessed for their response to gradients of human disturbance. The purpose of the study was to identify indicators that could be used for regulatory assessments under authority of the Clean Water Act--this requires that indicators distinguish anthropogenic disturbances from natural variation. Stony coral indicators were tested for correlation with human disturbance across gradients located on three different sides of the island. At the most intensely disturbed location, five of eight primary indicators were highly correlated with distance from the source of disturbance: Coral taxa richness, average colony size, the coefficient of variation of colony size (an indicator of colony size heterogeneity), total topographic coral surface area, and live coral surface area. An additional set of exploratory indicators related to rarity, reproductive and spawning mode, and taxonomic identity were also screened for association with disturbance at the same location. For the other two locations, there were no significant changes in indicator values and therefore no discernible effects of human activity. Coral indicators demonstrated sufficient precision to detect levels of change that would be applicable in a regio

  6. Regional and local variability in recovery of shallow coral communities: Moorea, French Polynesia and central Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Done, T. J.; Dayton, P. K.; Dayton, A. E.; Steger, R.

    1991-01-01

    Coral communities at Moorea, French Polynesia, and on the Great Barrier Reef (GBR), Australia, were severely depleted by disturbances early in the 1980s. Corals were killed by the predatory starfish Acanthaster planci, by cyclones, and/or by depressed sea level. This study compares benthic community structure and coral population structures on three disturbed reefs (Vaipahu-Moorea; Rib and John Brewer Reefs-GBR) and one undisturbed reef (Davies Reef-GBR) in 1987 89. Moorea barrier reefs had been invaded by tall macrophytes Turbinaria ornata and Sargassum sp., whereas the damaged GBR reefs were colonised by a diverse mixture of short macrophytes, turfs and coralline algae. The disturbed areas had broadly similar patterns of living and dead standing coral, and similar progress in recolonisation, which suggests their structure may converge towards that of undisturbed Davies Reef. Corals occupying denuded areas at Vaipahu, Rib and John Brewer were small (median diameter 5 cm in each case) and sparse (means 4 8 m-2) compared to longer established corals at Davies Reef (median diameter 9 cm; mean 18 m-2). At Moorea, damselfish and sea urchins interacted with corals in ways not observed in the GBR reefs. Territories of the damselfish Stegastes nigricans covered much of Moorea's shallow reef top. They had significantly higher diversity and density of post-disturbance corals than areas outside of territories, suggesting that the damselfish exerts some influences on coral community dynamics. Sea urchins on Moorea ( Diadema setosum Echinometra mathaei, Echinotrix calamaris) were causing widespread destruction of dead standing coral skeletons. Overall, it appears that the future direction and speed of change in the communities will be explicable more in terms of local than regional processes.

  7. Commencement on a Coral Reef

    ERIC Educational Resources Information Center

    Webster, Steven K.

    1973-01-01

    Describes an environmental program in which sixteen students and three biology teachers from Northfield Mount Hermon School in Massachusetts spent two weeks examining the ecology of a Caribbean reef.. (JR)

  8. Nitrification on a coral reef.

    PubMed

    Webb, K L; Wiebe, W J

    1975-09-01

    We report that the algal pavement just behind the reef crest at Enewetak Atoll produces nitrate at measurable rates. In situ and in vitro incubations with N-Serve indicate that the autotrophic pathway involving two separate organisms is effective in this oxidation of ammonia to nitrate. Significant nitrification is indicated throughout the reef environment; Nitrobacter agilis has specifically been identified as at least one of the organisms responsible for the terminal oxidation of nitrite to nitrate.

  9. Distribution of CpG Motifs in Upstream Gene Domains in a Reef Coral and Sea Anemone: Implications for Epigenetics in Cnidarians

    PubMed Central

    Marsh, Adam G.; Hoadley, Kenneth D.; Warner, Mark E.

    2016-01-01

    Coral reefs are under assault from stressors including global warming, ocean acidification, and urbanization. Knowing how these factors impact the future fate of reefs requires delineating stress responses across ecological, organismal and cellular scales. Recent advances in coral reef biology have integrated molecular processes with ecological fitness and have identified putative suites of temperature acclimation genes in a Scleractinian coral Acropora hyacinthus. We wondered what unique characteristics of these genes determined their coordinate expression in response to temperature acclimation, and whether or not other corals and cnidarians would likewise possess these features. Here, we focus on cytosine methylation as an epigenetic DNA modification that is responsive to environmental stressors. We identify common conserved patterns of cytosine-guanosine dinucleotide (CpG) motif frequencies in upstream promoter domains of different functional gene groups in two cnidarian genomes: a coral (Acropora digitifera) and an anemone (Nematostella vectensis). Our analyses show that CpG motif frequencies are prominent in the promoter domains of functional genes associated with environmental adaptation, particularly those identified in A. hyacinthus. Densities of CpG sites in upstream promoter domains near the transcriptional start site (TSS) are 1.38x higher than genomic background levels upstream of -2000 bp from the TSS. The increase in CpG usage suggests selection to allow for DNA methylation events to occur more frequently within 1 kb of the TSS. In addition, observed shifts in CpG densities among functional groups of genes suggests a potential role for epigenetic DNA methylation within promoter domains to impact functional gene expression responses in A. digitifera and N. vectensis. Identifying promoter epigenetic sequence motifs among genes within specific functional groups establishes an approach to describe integrated cellular responses to environmental stress in

  10. Distribution of CpG Motifs in Upstream Gene Domains in a Reef Coral and Sea Anemone: Implications for Epigenetics in Cnidarians.

    PubMed

    Marsh, Adam G; Hoadley, Kenneth D; Warner, Mark E

    2016-01-01

    Coral reefs are under assault from stressors including global warming, ocean acidification, and urbanization. Knowing how these factors impact the future fate of reefs requires delineating stress responses across ecological, organismal and cellular scales. Recent advances in coral reef biology have integrated molecular processes with ecological fitness and have identified putative suites of temperature acclimation genes in a Scleractinian coral Acropora hyacinthus. We wondered what unique characteristics of these genes determined their coordinate expression in response to temperature acclimation, and whether or not other corals and cnidarians would likewise possess these features. Here, we focus on cytosine methylation as an epigenetic DNA modification that is responsive to environmental stressors. We identify common conserved patterns of cytosine-guanosine dinucleotide (CpG) motif frequencies in upstream promoter domains of different functional gene groups in two cnidarian genomes: a coral (Acropora digitifera) and an anemone (Nematostella vectensis). Our analyses show that CpG motif frequencies are prominent in the promoter domains of functional genes associated with environmental adaptation, particularly those identified in A. hyacinthus. Densities of CpG sites in upstream promoter domains near the transcriptional start site (TSS) are 1.38x higher than genomic background levels upstream of -2000 bp from the TSS. The increase in CpG usage suggests selection to allow for DNA methylation events to occur more frequently within 1 kb of the TSS. In addition, observed shifts in CpG densities among functional groups of genes suggests a potential role for epigenetic DNA methylation within promoter domains to impact functional gene expression responses in A. digitifera and N. vectensis. Identifying promoter epigenetic sequence motifs among genes within specific functional groups establishes an approach to describe integrated cellular responses to environmental stress in

  11. Symbiont diversity may help coral reefs survive moderate climate change.

    PubMed

    Baskett, Marissa L; Gaines, Steven D; Nisbet, Roger M

    2009-01-01

    Given climate change, thermal stress-related mass coral-bleaching events present one of the greatest anthropogenic threats to coral reefs. While corals and their symbiotic algae may respond to future temperatures through genetic adaptation and shifts in community compositions, the climate may change too rapidly for coral response. To test this potential for response, here we develop a model of coral and symbiont ecological dynamics and symbiont evolutionary dynamics. Model results without variation in symbiont thermal tolerance predict coral reef collapse within decades under multiple future climate scenarios, consistent with previous threshold-based predictions. However, model results with genetic or community-level variation in symbiont thermal tolerance can predict coral reef persistence into the next century, provided low enough greenhouse gas emissions occur. Therefore, the level of greenhouse gas emissions will have a significant effect on the future of coral reefs, and accounting for biodiversity and biological dynamics is vital to estimating the size of this effect.

  12. Oceanographic and behavioural assumptions in models of the fate of coral and coral reef fish larvae

    PubMed Central

    Wolanski, Eric; Kingsford, Michael J.

    2014-01-01

    A predictive model of the fate of coral reef fish larvae in a reef system is proposed that combines the oceanographic processes of advection and turbulent diffusion with the biological process of horizontal swimming controlled by olfactory and auditory cues within the timescales of larval development. In the model, auditory cues resulted in swimming towards the reefs when within hearing distance of the reef, whereas olfactory cues resulted in the larvae swimming towards the natal reef in open waters by swimming against the concentration gradients in the smell plume emanating from the natal reef. The model suggested that the self-seeding rate may be quite large, at least 20% for the larvae of rapidly developing reef fish species, which contrasted with a self-seeding rate less than 2% for non-swimming coral larvae. The predicted self-recruitment rate of reefs was sensitive to a number of parameters, such as the time at which the fish larvae reach post-flexion, the pelagic larval duration of the larvae, the horizontal turbulent diffusion coefficient in reefal waters and the horizontal swimming behaviour of the fish larvae in response to auditory and olfactory cues, for which better field data are needed. Thus, the model suggested that high self-seeding rates for reef fish are possible, even in areas where the ‘sticky water’ effect is minimal and in the absence of long-term trapping in oceanic fronts and/or large-scale oceanic eddies or filaments that are often argued to facilitate the return of the larvae after long periods of drifting at sea. PMID:24966233

  13. Oceanographic and behavioural assumptions in models of the fate of coral and coral reef fish larvae.

    PubMed

    Wolanski, Eric; Kingsford, Michael J

    2014-09-06

    A predictive model of the fate of coral reef fish larvae in a reef system is proposed that combines the oceanographic processes of advection and turbulent diffusion with the biological process of horizontal swimming controlled by olfactory and auditory cues within the timescales of larval development. In the model, auditory cues resulted in swimming towards the reefs when within hearing distance of the reef, whereas olfactory cues resulted in the larvae swimming towards the natal reef in open waters by swimming against the concentration gradients in the smell plume emanating from the natal reef. The model suggested that the self-seeding rate may be quite large, at least 20% for the larvae of rapidly developing reef fish species, which contrasted with a self-seeding rate less than 2% for non-swimming coral larvae. The predicted self-recruitment rate of reefs was sensitive to a number of parameters, such as the time at which the fish larvae reach post-flexion, the pelagic larval duration of the larvae, the horizontal turbulent diffusion coefficient in reefal waters and the horizontal swimming behaviour of the fish larvae in response to auditory and olfactory cues, for which better field data are needed. Thus, the model suggested that high self-seeding rates for reef fish are possible, even in areas where the 'sticky water' effect is minimal and in the absence of long-term trapping in oceanic fronts and/or large-scale oceanic eddies or filaments that are often argued to facilitate the return of the larvae after long periods of drifting at sea.

  14. Development and implementation of coral reef biocriteria in U.S. jurisdictions.

    PubMed

    Bradley, Patricia; Fisher, William S; Bell, Heidi; Davis, Wayne; Chan, Valerie; LoBue, Charles; Wiltse, Wendy

    2009-03-01

    Coral reefs worldwide are declining at an alarming rate and are under continuous threat from both natural and anthropogenic environmental stressors. Warmer sea temperatures attributed to global climate change and numerous human activities at local scales place these valuable ecosystems at risk. Reefs provide numerous services, including shoreline protection, fishing, tourism and biological diversity, which are lost through physical damage, overfishing, and pollution. Pollution can be controlled under provisions of the Clean Water Act, but these options have not been fully employed to protect coral reefs. No U.S. jurisdiction has implemented coral reef biocriteria, which are narrative or quantitative water quality standards based on the condition of a biological resource or assemblage. The President's Ocean Action Plan directs the U.S. Environmental Protection Agency (EPA) to develop biological assessment methods and biological criteria for evaluating and maintaining the health of coral reef ecosystems. EPA has formed the Coral Reef Biocriteria Working Group (CRBWG) to foster development of coral reef biocriteria through focused research, evaluation and communication among Agency partners and U.S. jurisdictions. Ongoing CRBWG activities include development and evaluation of a rapid bioassessment protocol for application in biocriteria programs; development of a survey design and monitoring strategy for the U.S. Virgin Islands; comprehensive reviews of biocriteria approaches proposed by states and territories; and assembly of data from a variety of monitoring programs for additional metrics. Guidance documents are being prepared to assist U.S. jurisdictions in reaching protective and defensible biocriteria.

  15. Robust Performance of Marginal Pacific Coral Reef Habitats in Future Climate Scenarios.

    PubMed

    Freeman, Lauren A

    2015-01-01

    Coral reef ecosystems are under dual threat from climate change. Increasing sea surface temperatures and thermal stress create environmental limits at low latitudes, and decreasing aragonite saturation state creates environmental limits at high latitudes. This study examines the response of unique coral reef habitats to climate change in the remote Pacific, using the National Center for Atmospheric Research Community Earth System Model version 1 alongside the species distribution algorithm Maxent. Narrow ranges of physico-chemical variables are used to define unique coral habitats and their performance is tested in future climate scenarios. General loss of coral reef habitat is expected in future climate scenarios and has been shown in previous studies. This study found exactly that for most of the predominant physico-chemical environments. However, certain coral reef habitats considered marginal today at high latitude, along the equator and in the eastern tropical Pacific were found to be quite robust in climate change scenarios. Furthermore, an environmental coral reef refuge previously identified in the central south Pacific near French Polynesia was further reinforced. Studying the response of specific habitats showed that the prevailing conditions of this refuge during the 20th century shift to a new set of conditions, more characteristic of higher latitude coral reefs in the 20th century, in future climate scenarios projected to 2100.

  16. African and Asian dust: from desert soils to coral reefs

    USGS Publications Warehouse

    Garrison, Virginia H.; Shinn, Eugene A.; Foreman, William T.; Griffin, Dale W.; Holmes, Charles W.; Kellogg, Christina A.; Majewski, Michael S.; Richardson, Laurie L.; Ritchie, Kim B.; Smith, Garriet W.

    2003-01-01

    Many hypotheses have been proposed to explain the decline of coral reefs throughout the world, but none adequately accounts for the lack of recovery of reefs or the wide geographical distribution of coral diseases. The processes driving the decline remain elusive. Hundreds of millions of tons of dust transported annually from Africa and Asia to the Americas may be adversely affecting coral reefs and other downwind ecosystems. Viable microorganisms, macro- and micronutrients, trace metals, and an array of organic contaminants carried in the dust air masses and deposited in the oceans and on land may play important roles in the complex changes occurring on coral reefs worldwide.

  17. Shifting paradigms in restoration of the world's coral reefs.

    PubMed

    van Oppen, Madeleine J H; Gates, Ruth D; Blackall, Linda L; Cantin, Neal; Chakravarti, Leela J; Chan, Wing Y; Cormick, Craig; Crean, Angela; Damjanovic, Katarina; Epstein, Hannah; Harrison, Peter L; Jones, Thomas A; Miller, Margaret; Pears, Rachel J; Peplow, Lesa M; Raftos, David A; Schaffelke, Britta; Stewart, Kristen; Torda, Gergely; Wachenfeld, David; Weeks, Andrew R; Putnam, Hollie M

    2017-03-01

    Many ecosystems around the world are rapidly deteriorating due to both local and global pressures, and perhaps none so precipitously as coral reefs. Management of coral reefs through maintenance (e.g., marine-protected areas, catchment management to improve water quality), restoration, as well as global and national governmental agreements to reduce greenhouse gas emissions (e.g., the 2015 Paris Agreement) is critical for the persistence of coral reefs. Despite these initiatives, the health and abundance of corals reefs are rapidly declining and other solutions will soon be required. We have recently discussed options for using assisted evolution (i.e., selective breeding, assisted gene flow, conditioning or epigenetic programming, and the manipulation of the coral microbiome) as a means to enhance environmental stress tolerance of corals and the success of coral reef restoration efforts. The 2014-2016 global coral bleaching event has sharpened the focus on such interventionist approaches. We highlight the necessity for consideration of alternative (e.g., hybrid) ecosystem states, discuss traits of resilient corals and coral reef ecosystems, and propose a decision tree for incorporating assisted evolution into restoration initiatives to enhance climate resilience of coral reefs.

  18. Coral growth on three reefs: development of recovery benchmarks using a space for time approach

    NASA Astrophysics Data System (ADS)

    Done, T. J.; Devantier, L. M.; Turak, E.; Fisk, D. A.; Wakeford, M.; van Woesik, R.

    2010-12-01

    This 14-year study (1989-2003) develops recovery benchmarks based on a period of very strong coral recovery in Acropora-dominated assemblages on the Great Barrier Reef (GBR) following major setbacks from the predatory sea-star Acanthaster planci in the early 1980s. A space for time approach was used in developing the benchmarks, made possible by the choice of three study reefs (Green Island, Feather Reef and Rib Reef), spread along 3 degrees of latitude (300 km) of the GBR. The sea-star outbreaks progressed north to south, causing death of corals that reached maximum levels in the years 1980 (Green), 1982 (Feather) and 1984 (Rib). The reefs were initially surveyed in 1989, 1990, 1993 and 1994, which represent recovery years 5-14 in the space for time protocol. Benchmark trajectories for coral abundance, colony sizes, coral cover and diversity were plotted against nominal recovery time (years 5-14) and defined as non-linear functions. A single survey of the same three reefs was conducted in 2003, when the reefs were nominally 1, 3 and 5 years into a second recovery period, following further Acanthaster impacts and coincident coral bleaching events around the turn of the century. The 2003 coral cover was marginally above the benchmark trajectory, but colony density (colonies.m-2) was an order of magnitude lower than the benchmark, and size structure was biased toward larger colonies that survived the turn of the century disturbances. The under-representation of small size classes in 2003 suggests that mass recruitment of corals had been suppressed, reflecting low regional coral abundance and depression of coral fecundity by recent bleaching events. The marginally higher cover and large colonies of 2003 were thus indicative of a depleted and aging assemblage not yet rejuvenated by a strong cohort of recruits.

  19. Climate Change, Human Impacts, and the Resilience of Coral Reefs

    NASA Astrophysics Data System (ADS)

    Hughes, T. P.; Baird, A. H.; Bellwood, D. R.; Card, M.; Connolly, S. R.; Folke, C.; Grosberg, R.; Hoegh-Guldberg, O.; Jackson, J. B. C.; Kleypas, J.; Lough, J. M.; Marshall, P.; Nyström, M.; Palumbi, S. R.; Pandolfi, J. M.; Rosen, B.; Roughgarden, J.

    2003-08-01

    The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming.

  20. Warm-water coral reefs and climate change

    NASA Astrophysics Data System (ADS)

    Spalding, Mark D.; Brown, Barbara E.

    2015-11-01

    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.

  1. Warm-water coral reefs and climate change.

    PubMed

    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.

  2. Climate change, human impacts, and the resilience of coral reefs.

    PubMed

    Hughes, T P; Baird, A H; Bellwood, D R; Card, M; Connolly, S R; Folke, C; Grosberg, R; Hoegh-Guldberg, O; Jackson, J B C; Kleypas, J; Lough, J M; Marshall, P; Nyström, M; Palumbi, S R; Pandolfi, J M; Rosen, B; Roughgarden, J

    2003-08-15

    The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming.

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

    USGS Publications Warehouse

    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.

  4. ICE-6G models of postglacial relative sea-level history applied to Holocene coral reef and mangrove records of the western Caribbean

    NASA Astrophysics Data System (ADS)

    Toscano, M. A.; Peltier, W. R.; Drummond, R.; Gonzalez, J.

    2012-12-01

    Fossil coral reefs and mangrove peat accumulations at western Caribbean sites along a latitudinal gradient from the Florida Keys through Belize and Panama provide dated and interpreted 8,000 year Holocene sea-level records for comparison with RSL predictions of the ICE-6G (VM5A, VM5B; L90) models of glacio-hydro-isostatic adjustment, with and without rotational feedback. These presumably passive continental margin sites provide the means to establish a N-S spatial trend in the varying influences of GIA, eustatic components of Holocene sea level, extent of forebulge collapse and influence of rotational feedback over a 20° latitudinal range. Previous ICE6G (VM5A) model-coral data comparisons for St Croix, USVI, Antigua, Martinique and Barbados (Toscano, Peltier and Drummond, 2011, QSR) along the eastern Caribbean plate and island arc illustrated the close model-data compatibility, the influence of rotational feedback acting as a significant factor in reducing misfits, and the need for high quality in situ data to confirm the extension of the proglacial forebulge into tropical latitudes. The gradient of western Caribbean continental shelf sites comprises a much more varied range of model-data relationships based on extensive combined Acropora palmata (reef crest coral) and Rhizophora mangle (microtidal mangrove) peat datasets in all cases. Starting at the northernmost region with the Florida Keys, there exist negative model misfits to the data, suggesting the possibility of a positive tectonic overprint upon expectations related to the glacial isostatic adjustment process acting alone, even though this region is normally believed to be tectonically stable. The largest multi-proxy database from Belize supports the likelihood of increasing rates of subsidence from north to south in the Belize Lagoon, which may account for numerous positive GIA model-data misfits. The southernmost site at Panama is most similar to Belize in the possible nature of tectonic influences on

  5. Mass spawning of corals on a high latitude coral reef

    NASA Astrophysics Data System (ADS)

    Babcock, R. C.; Wills, B. L.; Simpson, C. J.

    1994-07-01

    Evidence is presented that at least 60% of the 184 species of scleractinian corals found on reefs surrounding the Houtman Abrolhos Islands (Western Australia) participate in a late summer mass spawning. These populations are thus reproductively active, despite most species being at the extreme southern limit of their latitudinal range (28° 29°S). In the present study, coral mass spawning occurred in the same month on both temperate (Houtman-Abrolhos) and tropical (Ningaloo) reefs of Western Australia, despite more than two months difference in the timing of seasonal temperture minima between the two regions. This concurrence in the month of spawning suggests that temperature does not operate as a simple direct proximate cue for seasonal spawning synchrony in these populations. Seasonal variation in photoperiod may provide a similar and more reliable signal in the two regions, and thus might be more likely to synchronize the seasonal reproductive rhythms of these corals. Also there is overlap in the nights of mass spawning on the Houtman Abrolhos and tropical reefs of Western Australia, despite significant differences in tidal phase and amplitude between the two regions. This indicates that tidal cycle does not synchronize with the night(s) of spawning on these reefs. Spawning is more likely to be synchronised by lunar cycles. The co-occurrence of the mass spawning with spring tides in Houtman Abrolhos coral populations may be evidence of a genetic legacy inherited from northern, tropical ancestors. Micro-tidal regimes in the Houtman Abrolhos region may have exerted insufficient selective pressure to counteract this legacy.

  6. A modern Sr/Ca-δ18O-sea surface temperature calibration for Isopora corals on the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Brenner, Logan D.; Linsley, Braddock K.; Potts, Donald C.

    2017-02-01

    Isopora (Acroporidae) is a genus of often encrusting, branching to submassive corals that are common in many shallow habitats on modern and fossil Indo-West Pacific reefs. Although abundant, Isopora is largely absent from paleoceanographic literature. The scarcity of large Porites and the abundance of Isopora retrieved from the Great Barrier Reef (GBR) on Integrated Ocean Drilling Program Expedition 325 focused paleoceanographic attention on Isopora. Here we provide the first independent high-resolution calibration of both Sr/Ca and δ18O for temperature analyses based on Isopora and demonstrate its consistency with Porites records. We developed modern skeletal Sr/Ca- and δ18O-sea surface temperature (SST) calibrations based on five modern Isopora colonies from Heron Island in the southern GBR. Pairing the coral Sr/Ca record with monthly SST data yielded Sr/Ca-SST sensitivities from -0.061 ± 0.004 (centered) to -0.083 ± 0.007 (raw) mmol/mol °C-1 based on reduced major axis regressions. These sensitivities are in the middle of the range of published Porites values and overlap most published values for Isopora, -0.075 ± 0.011 to -0.065 ± 0.011 mmol/mol °C-1. The δ18O-SST sensitivities range from -0.184 ± 0.014 (centered) to -0.185 ± 0.014 (raw) ‰ °C-1, assuming that all seasonal variation in δ18O was due to SST. These δ18O-SST sensitivities are smaller than the widely accepted value of -0.23‰ °C-1 for biogenic aragonite but are at the upper end of high-resolution Porites-defined sensitivities that are consistently less than the aforementioned established value. Our results validate the use of Isopora as an alternative source of paleoceanographic records in habitats where large massive Porites are scarce or absent.

  7. Rapid Recent Warming of Coral Reefs in the Florida Keys

    PubMed Central

    Manzello, Derek P.

    2015-01-01

    Coral reef decline in the Florida Keys has been well-publicized, controversial, and polarizing owing to debate over the causative agent being climate change versus overfishing. The recurrence of mass bleaching in 2014, the sixth event since 1987, prompted a reanalysis of temperature data. The summer and winter of 2014 were the warmest on record. The oldest known in-situ temperature record of any coral reef is from Hens and Chickens Reef (H&C) in the Florida Keys, which showed significant warming from 1975–2014. The average number of days ≥31.5 and 32oC per year increased 2670% and 2560%, respectively, from the mid-1990 s to present relative to the previous 20 years. In every year after 1992 and 1994, maximum daily average temperatures exceeded 30.5 and 31°C, respectively. From 1975–1994, temperatures were <31 °C in 61% of years, and in 44% of the years prior to 1992 temperatures were <30.5 °C. The measured rate of warming predicts the start of annual bleaching between 2020 and 2034, sooner than expected from climate models and satellite-based sea temperatures. These data show that thermal stress is increasing and occurring on a near-annual basis on Florida Keys reefs due to ocean warming from climate change. PMID:26567884

  8. Rapid Recent Warming of Coral Reefs in the Florida Keys.

    PubMed

    Manzello, Derek P

    2015-11-16

    Coral reef decline in the Florida Keys has been well-publicized, controversial, and polarizing owing to debate over the causative agent being climate change versus overfishing. The recurrence of mass bleaching in 2014, the sixth event since 1987, prompted a reanalysis of temperature data. The summer and winter of 2014 were the warmest on record. The oldest known in-situ temperature record of any coral reef is from Hens and Chickens Reef (H&C) in the Florida Keys, which showed significant warming from 1975-2014. The average number of days ≥31.5 and 32(o)C per year increased 2670% and 2560%, respectively, from the mid-1990 s to present relative to the previous 20 years. In every year after 1992 and 1994, maximum daily average temperatures exceeded 30.5 and 31°C, respectively. From 1975-1994, temperatures were <31 °C in 61% of years, and in 44% of the years prior to 1992 temperatures were <30.5 °C. The measured rate of warming predicts the start of annual bleaching between 2020 and 2034, sooner than expected from climate models and satellite-based sea temperatures. These data show that thermal stress is increasing and occurring on a near-annual basis on Florida Keys reefs due to ocean warming from climate change.

  9. Biology and ecology of the hydrocoral millepora on coral reefs.

    PubMed

    Lewis, John B

    2006-01-01

    Millepores are colonial polypoidal hydrozoans secreting an internal calcareous skeleton of an encrusting or upright form, often of considerable size. Defensive polyps protruding from the skeleton are numerous and highly toxic and for this reason millepores are popularly known as "stinging corals" or "fire corals." In shallow tropical seas millepore colonies are conspicuous on coral reefs and may be locally abundant and important reef-framework builders. The history of systematic research on the Milleporidae and the sister family Stylasteridae is rich and full with the works of early naturalists beginning with Linnaeus. Seventeen living millepore species are recognised. Marked phenotypic variation in form and structure of colonies is characteristic of the genus Millepora. The first published descriptions of the anatomy and histology of millepores were by H. N. Moseley in one of the Challenger Expedition reports. These original, detailed accounts by Moseley remain valid and, except for recent descriptions of the ultrastructure of the skeleton and skeletogenic tissues, have not needed much modification. Millepores occur worldwide on coral reefs at depths of between 1 and 40 m and their distribution on reefs is generally zoned in response to physical factors. Colonies may be abundant locally on coral reefs but usually comprise <10% of the overall surface cover. Growth rates of colonies are similar to the measured rates of branching and platelike scleractinian corals. Millepores are voracious zooplankton feeders and they obtain part of their nutrition from autotrophic sources, photosynthetic production by symbiotic zooxanthellae. Reproduction in millepores is characterised by alternation of generations with a well-developed polypoid stage that buds off planktonic medusae. Sexual reproduction is seasonal for known species and the medusae have a brief planktonic life. Asexual production is achieved by sympodial growth, the production of new skeleton and soft tissue along

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Coral Reef Resilience, Tipping Points and the Strength of Herbivory

    PubMed Central

    Holbrook, Sally J.; Schmitt, Russell J.; Adam, Thomas C.; Brooks, Andrew J.

    2016-01-01

    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. PMID:27804977

  12. Coral Reef Resilience, Tipping Points and the Strength of Herbivory.

    PubMed

    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.

  13. CORAL REEFS. Genomic determinants of coral heat tolerance across latitudes.

    PubMed

    Dixon, Groves B; Davies, Sarah W; Aglyamova, Galina A; Meyer, Eli; Bay, Line K; Matz, Mikhail V

    2015-06-26

    As global warming continues, reef-building corals could avoid local population declines through "genetic rescue" involving exchange of heat-tolerant genotypes across latitudes, but only if latitudinal variation in thermal tolerance is heritable. Here, we show an up-to-10-fold increase in odds of survival of coral larvae under heat stress when their parents come from a warmer lower-latitude location. Elevated thermal tolerance was associated with heritable differences in expression of oxidative, extracellular, transport, and mitochondrial functions that indicated a lack of prior stress. Moreover, two genomic regions strongly responded to selection for thermal tolerance in interlatitudinal crosses. These results demonstrate that variation in coral thermal tolerance across latitudes has a strong genetic basis and could serve as raw material for natural selection.

  14. 10th Anniversary Review: a changing climate for coral reefs.

    PubMed

    Lough, Janice M

    2008-01-01

    Tropical coral reefs are charismatic ecosystems that house a significant proportion of the world's marine biodiversity. Their valuable goods and services are fundamental to the livelihood of large coastal populations in the tropics. The health of many of the world's coral reefs, and the goods and services they provide, have already been severely compromised, largely due to over-exploitation by a range of human activities. These local-scale impacts, with the appropriate government instruments, support and management actions, can potentially be controlled and even ameliorated. Unfortunately, other human actions (largely in countries outside of the tropics), by changing global climate, have added additional global-scale threats to the continued survival of present-day coral reefs. Moderate warming of the tropical oceans has already resulted in an increase in mass coral bleaching events, affecting nearly all of the world's coral reef regions. The frequency of these events will only increase as global temperatures continue to rise. Weakening of coral reef structures will be a more insidious effect of changing ocean chemistry, as the oceans absorb part of the excess atmospheric carbon dioxide. More intense tropical cyclones, changed atmospheric and ocean circulation patterns will all affect coral reef ecosystems and the many associated plants and animals. Coral reefs will not disappear but their appearance, structure and community make-up will radically change. Drastic greenhouse gas mitigation strategies are necessary to prevent the full consequences of human activities causing such alterations to coral reef ecosystems.

  15. Perturbation and change in coral reef communities

    PubMed Central

    Porter, James W.; Battey, James F.; Smith, G. Jason

    1982-01-01

    Ninety-six percent of surveyed shallow-water Dry Tortugas reef corals died during the severe winter of 1976-1977. Data from skeletal stains indicate that death occurred during the mid-January intrusion of 14°C water onto the reef. In deeper water, community parameters such as percent cover, species number, and relative abundance showed no significant change. However, an analysis of competitive interactions at the growing edges of adjacent colonies reveals a 70% reduction in space competition during this environmental disturbance. These results can explain high variability in the growth rate of Floridian reefs and demonstrate the importance of obtaining long-term spatial information to interpret successional dynamics of complex communities. Images PMID:16578761

  16. Surviving in a marine desert: the sponge loop retains resources within coral reefs.

    PubMed

    de Goeij, Jasper M; van Oevelen, Dick; Vermeij, Mark J A; Osinga, Ronald; Middelburg, Jack J; de Goeij, Anton F P M; Admiraal, Wim

    2013-10-04

    Ever since Darwin's early descriptions of coral reefs, scientists have debated how one of the world's most productive and diverse ecosystems can thrive in the marine equivalent of a desert. It is an enigma how the flux of dissolved organic matter (DOM), the largest resource produced on reefs, is transferred to higher trophic levels. Here we show that sponges make DOM available to fauna by rapidly expelling filter cells as detritus that is subsequently consumed by reef fauna. This "sponge loop" was confirmed in aquarium and in situ food web experiments, using (13)C- and (15)N-enriched DOM. The DOM-sponge-fauna pathway explains why biological hot spots such as coral reefs persist in oligotrophic seas--the reef's paradox--and has implications for reef ecosystem functioning and conservation strategies.

  17. The role of turtles as coral reef macroherbivores.

    PubMed

    Goatley, Christopher H R; Hoey, Andrew S; 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.

  18. Coral reef community composition in the context of disturbance history on the Great Barrier Reef, Australia.

    PubMed

    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

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

    PubMed Central

    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

  20. Nutrient supply from fishes facilitates macroalgae and suppresses corals in a Caribbean coral reef ecosystem.

    PubMed

    Burkepile, Deron E; Allgeier, Jacob E; Shantz, Andrew A; Pritchard, Catharine E; Lemoine, Nathan P; Bhatti, Laura H; Layman, Craig A

    2013-01-01

    On coral reefs, fishes can facilitate coral growth via nutrient excretion; however, as coral abundance declines, these nutrients may help facilitate increases in macroalgae. By combining surveys of reef communities with bioenergetics modeling, we showed that fish excretion supplied 25 times more nitrogen to forereefs in the Florida Keys, USA, than all other biotic and abiotic sources combined. One apparent result was a positive relationship between fish excretion and macroalgal cover on these reefs. Herbivore biomass also showed a negative relationship with macroalgal cover, suggesting strong interactions of top-down and bottom-up forcing. Nutrient supply by fishes also showed a negative correlation with juvenile coral density, likely mediated by competition between macroalgae and corals, suggesting that fish excretion may hinder coral recovery following large-scale coral loss. Thus, the impact of nutrient supply by fishes may be context-dependent and reinforce either coral-dominant or coral-depauperate reef communities depending on initial community states.

  1. Congruent patterns of connectivity can inform management for broadcast spawning corals on the Great Barrier Reef.

    PubMed

    Lukoschek, Vimoksalehi; Riginos, Cynthia; van Oppen, Madeleine J H

    2016-07-01

    Connectivity underpins the persistence and recovery of marine ecosystems. The Great Barrier Reef (GBR) is the world's largest coral reef ecosystem and managed by an extensive network of no-take zones; however, information about connectivity was not available to optimize the network's configuration. We use multivariate analyses, Bayesian clustering algorithms and assignment tests of the largest population genetic data set for any organism on the GBR to date (Acropora tenuis, >2500 colonies; >50 reefs, genotyped for ten microsatellite loci) to demonstrate highly congruent patterns of connectivity between this common broadcast spawning reef-building coral and its congener Acropora millepora (~950 colonies; 20 reefs, genotyped for 12 microsatellite loci). For both species, there is a genetic divide at around 19°S latitude, most probably reflecting allopatric differentiation during the Pleistocene. GBR reefs north of 19°S are essentially panmictic whereas southern reefs are genetically distinct with higher levels of genetic diversity and population structure, most notably genetic subdivision between inshore and offshore reefs south of 19°S. These broadly congruent patterns of higher genetic diversities found on southern GBR reefs most likely represent the accumulation of alleles via the southward flowing East Australia Current. In addition, signatures of genetic admixture between the Coral Sea and outer-shelf reefs in the northern, central and southern GBR provide evidence of recent gene flow. Our connectivity results are consistent with predictions from recently published larval dispersal models for broadcast spawning corals on the GBR, thereby providing robust connectivity information about the dominant reef-building genus Acropora for coral reef managers.

  2. Assessment of survival, mortality and recovery of coral reefs of East Kish Island, Persian Gulf.

    PubMed

    Jami, M J; Salehduost, A; Negarestan, H

    2010-10-15

    Coral reefs are specialized communities that develop clear, well-lit tropical and subtropical water; they provide shelter and canopy for great variety of organisms, living in mean temperature of 20 degrees C. Coral Bleaching and mortality have been associated with elevated seawater temperature. The aim of the study was to investigate coral bleaching and evaluate health condition of the corals. Distribution of coral reefs around Kish Island was determined by the Timed Swim (TS) technique. This survey carried out in 2 times (May and October, 2009) in 2 depths of 3-5 m and 6-10 m. Two Divers swam in constant speed for a set amount of time in three dive sites. The timed swim survey around the Kish Island showed that the most healthy live hard coral assemblages were found in the site called Persian Gulf seaport, whereas the greatest percentage of bleached corals were located in Jurassic Park station, located at the southeast of the Island. Branching corals (Acropora sp.) were bleached among all 3 stations and no sign of recovery could be detected. In Big coral site suitable substrate for accumulation of living organisms including Echinometra mathaie (sea urchin) existed due to presence of great amount of algae on dead corals and rocks. Based on the observation, it seems that the cause of reef destruction in Kish Island fall in to two categories, natural and human impacts.

  3. Persistence of coral-rudist reefs into the Late Cretaceous

    SciTech Connect

    Scott, R.W. ); Fernandez-Mendiola, P.A. ); Gili, E. ); Simo, A. )

    1990-04-01

    During the Early Cretaceous, coral-algal communities occupied deeper water habitats in the reef ecosystem, and rudist communities generally populated the shallow-water, carbonate-sand substrates. During the middle Cretaceous, however, coral-algal communities became less common, and Late Cretaceous reef communities consisted of both rudist-dominated and rudist-coral communities. In the Pyrenean basins and other basins in the Mediterranean, coral associations co-existed with rudists forming complex buildups at the shelf-edge. In some parts of these buildups corals were nearly as abundant as rudists; in some complex buildups large coral colonies encrusted the rudists. Behind the shelf margin cylindrical, elevator rudists dominated the lenticular thickets that were interspersed with carbonate sands. Global changes in oceanic conditions, such as marine productivity and oxygen content, may have stressed the deeper coral-algal reef communities leaving rudists as the major shallow reef biota in Caribbean reefs. However, the co-occurrence of corals with rudists in these Pyrenean complex buildups suggests that corals were able to compete with rudists for resources. The corals in the complex buildups generally belong to genera different from those in the coral-algal communities. Perhaps this ecological stress in the mid-Cretaceous resulted in the evolution of new coral taxa.

  4. Can we measure beauty? Computational evaluation of coral reef aesthetics.

    PubMed

    Haas, Andreas F; Guibert, Marine; Foerschner, Anja; Co, Tim; Calhoun, Sandi; George, Emma; Hatay, Mark; Dinsdale, Elizabeth; Sandin, Stuart A; Smith, Jennifer E; Vermeij, Mark J A; Felts, Ben; Dustan, Phillip; Salamon, Peter; Rohwer, Forest

    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, neglecting changes in their aesthetic appearance. Here we introduce a standardized computational approach to assess coral reef environments based on 109 visual features designed to evaluate the aesthetic appearance of art. The main feature groups include color intensity and diversity of the image, relative size, color, and distribution of discernable objects within the image, and texture. Specific coral reef aesthetic values combining all 109 features were calibrated against an established biogeochemical assessment (NCEAS) using machine learning algorithms. These values were generated for ∼2,100 random photographic images collected from 9 coral reef locations exposed to varying levels of anthropogenic influence across 2 ocean systems. Aesthetic values proved accurate predictors of the NCEAS scores (root mean square error < 5 for N ≥ 3) and significantly correlated to microbial abundance at each site. This shows that mathematical approaches designed to assess the aesthetic appearance of photographic images can be used as an inexpensive monitoring tool for coral reef ecosystems. It further suggests that human perception of aesthetics is not purely subjective but influenced by inherent reactions towards measurable visual cues. By quantifying aesthetic features of coral reef systems this method provides a cost efficient monitoring tool that targets one of the most important socioeconomic values of coral reefs directly tied to revenue for its local population.

  5. Coral reefs in crisis: reversing the biotic death spiral.

    PubMed

    Hay, Mark E; Rasher, Douglas B

    2010-09-23

    Coral reefs are disappearing due to global warming, overfishing, ocean acidification, pollution, and interactions of these and other stresses. Ecologically informed management of fishes that facilitate corals by suppressing seaweeds may be our best bet for bringing reefs back from the brink of extinction.

  6. Repair of Coral Reefs Following Large Vessel Groundings

    DTIC Science & Technology

    2003-09-01

    Between 1997 and 2002, the National Oceanic and Atmospheric Administration (NOAA), National Marine Sanctuaries Division, conducted three major coral ... reef repairs. The repairs were conducted in response to large vessel groundings on coral reefs. The purpose of the repairs was to mitigate for

  7. Functionally diverse reef-fish communities ameliorate coral disease

    PubMed Central

    Raymundo, Laurie J.; Halford, Andrew R.; Maypa, Aileen P.; Kerr, Alexander M.

    2009-01-01

    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. PMID:19805081

  8. Functionally diverse reef-fish communities ameliorate coral disease.

    PubMed

    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.

  9. 76 FR 59377 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ..., Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and Invertebrates Fishery Management... Fishery Management Plans (FMPs) for Reef Fish Resources, Spiny Lobster, Queen Conch, and Coral and Reef... and coral and reef associated plants and invertebrates species. The 2011 Caribbean ACL Amendment...

  10. Modeling regional coral reef responses to global warming and changes in ocean chemistry: Caribbean case study

    USGS Publications Warehouse

    Buddemeier, R.W.; Lane, D.R.; Martinich, J.A.

    2011-01-01

    Climatic change threatens the future of coral reefs in the Caribbean and the important ecosystem services they provide. We used a simulation model [Combo ("COral Mortality and Bleaching Output")] to estimate future coral cover in the part of the eastern Caribbean impacted by a massive coral bleaching event in 2005. Combo calculates impacts of future climate change on coral reefs by combining impacts from long-term changes in average sea surface temperature (SST) and ocean acidification with impacts from episodic high temperature mortality (bleaching) events. We used mortality and heat dose data from the 2005 bleaching event to select historic temperature datasets, to use as a baseline for running Combo under different future climate scenarios and sets of assumptions. Results suggest a bleak future for coral reefs in the eastern Caribbean. For three different emissions scenarios from the Intergovernmental Panel on Climate Change (IPCC; B1, A1B, and A1FI), coral cover on most Caribbean reefs is projected to drop below 5% by the year 2035, if future mortality rates are equivalent to some of those observed in the 2005 event (50%). For a scenario where corals gain an additional 1-1. 5??C of heat tolerance through a shift in the algae that live in the coral tissue, coral cover above 5% is prolonged until 2065. Additional impacts such as storms or anthropogenic damage could result in declines in coral cover even faster than those projected here. These results suggest the need to identify and preserve the locations that are likely to have a higher resiliency to bleaching to save as many remnant populations of corals as possible in the face of projected wide-spread coral loss. ?? 2011 The Author(s).

  11. Report Evaluates Importance of Coral Reefs and Mangroves

    NASA Astrophysics Data System (ADS)

    Kumar, Mohi

    2006-02-01

    Thirty percent of the world's coral reefs are seriously damaged, and possibly no pristine reefs remain, according to a 24 January report by the World Conservation Monitoring Centre of the United Nations Environment Programme (UNEP) issued in the wake of the 26 December 2004 Indian Ocean tsunami. ``The Indian Ocean tsunami brought a lot of attention to coral reefs and mangroves,'' said Sue Wells, lead author of the report, In the Front Line: Shoreline Protection and other Ecosystem Services from Mangroves and Coral Reefs. ``Were they badly damaged? Did they play a role in buffering damage on shore?''

  12. Arrecifes de Coral: Una Coleccion de Actividades en Espanol para Estudiantes de Escuela Intermedia (Coral Reefs: A Spanish Compilation of Activities for Middle School Students).

    ERIC Educational Resources Information Center

    Walker, Sharon H.; Newton, R. Amanda; Ortiz, Alida

    This activity book for middle school students on coral reefs is divided into 10 sections. Section 1 is the introduction. Section 2 describes what coral reefs are while section 3 describes how coral reefs reproduce and grow. Section 4 describes where coral reefs are found, and section 5 describes life on a coral reef. Section 6 describes the…

  13. 77 FR 12567 - Proposed Information Collection; Comment Request; Pacific Islands Region Coral Reef Ecosystems...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-01

    ... Islands Region Coral Reef Ecosystems Logbook and Reporting AGENCY: National Oceanic and Atmospheric... Special Coral Reef Ecosystem Fishing Permit (authorized under the Fishery Management Plan for Coral Reef... the logbooks is used to obtain fish catch/fishing effort data on coral reef fishes and...

  14. DoD Coral Reef Protection and Management Program

    DTIC Science & Technology

    2004-08-01

    DoD Coral Reef Protection and Management Program (CRTF) goals are to 1) Ensure sustainable use of marine resources for DoD operations and training...exercises. 2) Identify and map locations of DoD coral reef ecosystems. 3) Inventory and monitor coral resources and tropical near-shore environments. 4...training for active duty DoD divers. 6) Support U.S. Coral Reef Task Force initiatives. 7) Promote interagency cooperation. 8) Promote DoD stewardship, education and public outreach.

  15. Environmental quality and preservation; reefs, corals, and carbonate sands; guides to reef-ecosystem health and environment

    USGS Publications Warehouse

    Lidz, Barbara H.

    2001-01-01

    reefs in South Florida, relative to type of underlying bedrock morphology, and their varied natural response to rising sea level. These studies also assess movement and accumulation of sands, relative to direction of prevailing energy, and origin of the component sand grains. Geophysical data collected with highresolution sound-wave instruments that provide pictures of the sediment and bedrock are used to interpret sediment thickness. Reef thickness is determined by collecting limestone rock cores by drilling. Drill cores through reefs are used to identify the coral species that built them and to determine how reefs reacted to rising sea level. These data are supplemented by using isotope-dating techniques to derive the carbon-14 (C14) age of the corals and mangrove peat in the cores. Mangrove peat forms in very shallow water and at the shoreline but is found today buried beneath offshore reefs.

  16. Monitoring coral reefs, seagrasses and mangroves in Costa Rica (CARICOMP).

    PubMed

    Cortés, Jorge; Fonseca, Ana C; Nivia-Ruiz, Jaime; Nielsen-Muñoz, Vanessa; Samper-Villarreal, Jimena; Salas, Eva; Martínez, Solciré; Zamora-Trejos, Priscilla

    2010-10-01

    The coral reefs, seagrasses and mangroves from the Costa Rican Caribbean coast have been monitored since 1999 using the CARICOMP protocol. Live coral cover at Meager Shoal reef bank (7 to 10 m depth) at the Parque Nacional Cahuita (National Park), increased from 13.3% in 1999, to 28.2% in 2003, but decreased during the next 5 years to around 17.5%. Algal cover increased significantly since 2003 from 36.6% to 61.3% in 2008. The density of Diadema antillarum oscillated between 2 and 7ind/m2, while Echinometra viridis decreased significantly from 20 to 0.6ind/m2. Compared to other CARICOMP sites, live coral cover, fish diversity and density, and sea urchin density were low, and algal cover was intermediate. The seagrass site, also in the Parque Nacional Cahuita, is dominated by Thalassia testudinum and showed an intermediate productivity (2.7 +/- 1.15 g/m2/d) and biomass (822.8 +/- 391.84 g/m2) compared to other CARICOMP sites. Coral reefs and seagrasses at the Parque Nacional Cahuita continue to be impacted by high sediment loads from terrestrial origin. The mangrove forest at Gandoca, within the Refugio Nacional de Vida Silvestre Gandoca-Manzanillo (National Wildlife Refuge), surrounds a lagoon and it is dominated by the red mangrove, Rhizophora mangle. Productivity and flower production peak was in July. Biomass (14 kg/m2) and density (9.0 +/- 0.58 trees/100 m2) in Gandoca were relatively low compared to other CARICOMP sites, while productivity in July in Costa Rica (4 g/m2/d) was intermediate, similar to most CARICOMP sites. This mangrove is expanding and has low human impact thus far. Management actions should be taken to protect and preserve these important coastal ecosystems.

  17. Data-driven models for regional coral-reef dynamics.

    PubMed

    Żychaluk, Kamila; Bruno, John F; Clancy, Damian; McClanahan, Tim R; Spencer, Matthew

    2012-02-01

    Coral reefs have been affected by natural and anthropogenic disturbances. Coral cover has declined on many reefs, and macroalgae have increased on some. The existence of alternative stable states with high or low coral cover has been widely debated, but not clearly established. We evaluate the evidence for alternative stable states in benthic coral-reef dynamics in the Caribbean, Kenya and Great Barrier Reef (GBR), using stochastic semi-parametric models based on large numbers of time series of cover of hard corals, macroalgae and other components. Only the GBR showed a consistent short-term regional decline in coral cover. There was no evidence for regional increases in macroalgae. The equilibrium distributions of our models were close to recently observed distributions, and differed among regions. In all three regions, the equilibrium distributions were unimodal rather than bimodal, and thus did not suggest the existence of alternative stable states on a regional scale, under current conditions.

  18. Herbivore space use influences coral reef recovery

    PubMed Central

    Eynaud, Yoan; McNamara, Dylan E.; Sandin, Stuart A.

    2016-01-01

    Herbivores play an important role in marine communities. On coral reefs, the diversity and unique feeding behaviours found within this functional group can have a comparably diverse set of impacts in structuring the benthic community. Here, using a spatially explicit model of herbivore foraging, we explore how the spatial pattern of grazing behaviours impacts the recovery of a reef ecosystem, considering movements at two temporal scales—short term (e.g. daily foraging patterns) and longer term (e.g. monthly movements across the landscape). Model simulations suggest that more spatially constrained herbivores are more effective at conferring recovery capability by providing a favourable environment to coral recruitment and growth. Results also show that the composition of food available to the herbivore community is linked directly to the pattern of space use by herbivores. To date, most studies of variability among the impacts of herbivore species have considered the diversity of feeding modes and mouthparts. Our work provides a complementary view of spatial patterns of foraging, revealing that variation in movement behaviours alone can affect patterns of benthic change, and thus broadens our view of realized links between herbivore diversity and reef recovery. PMID:27429784

  19. Herbivore space use influences coral reef recovery.

    PubMed

    Eynaud, Yoan; McNamara, Dylan E; Sandin, Stuart A

    2016-06-01

    Herbivores play an important role in marine communities. On coral reefs, the diversity and unique feeding behaviours found within this functional group can have a comparably diverse set of impacts in structuring the benthic community. Here, using a spatially explicit model of herbivore foraging, we explore how the spatial pattern of grazing behaviours impacts the recovery of a reef ecosystem, considering movements at two temporal scales-short term (e.g. daily foraging patterns) and longer term (e.g. monthly movements across the landscape). Model simulations suggest that more spatially constrained herbivores are more effective at conferring recovery capability by providing a favourable environment to coral recruitment and growth. Results also show that the composition of food available to the herbivore community is linked directly to the pattern of space use by herbivores. To date, most studies of variability among the impacts of herbivore species have considered the diversity of feeding modes and mouthparts. Our work provides a complementary view of spatial patterns of foraging, revealing that variation in movement behaviours alone can affect patterns of benthic change, and thus broadens our view of realized links between herbivore diversity and reef recovery.

  20. Threatened Reef Corals of the World

    PubMed Central

    Huang, Danwei

    2012-01-01

    A substantial proportion of the world's living species, including one-third of the reef-building corals, are threatened with extinction and in pressing need of conservation action. In order to reduce biodiversity loss, it is important to consider species' contribution to evolutionary diversity along with their risk of extinction for the purpose of setting conservation priorities. Here I reconstruct the most comprehensive tree of life for the order Scleractinia (1,293 species) that includes all 837 living reef species, and employ a composite measure of phylogenetic distinctiveness and extinction risk to identify the most endangered lineages that would not be given top priority on the basis of risk alone. The preservation of these lineages, not just the threatened species, is vital for safeguarding evolutionary diversity. Tests for phylogeny-associated patterns show that corals facing elevated extinction risk are not clustered on the tree, but species that are susceptible, resistant or resilient to impacts such as bleaching and disease tend to be close relatives. Intensification of these threats or extirpation of the endangered lineages could therefore result in disproportionate pruning of the coral tree of life. PMID:22479633

  1. Simulated NASA Satellite Data Products for the NOAA Integrated Coral Reef Observation Network/Coral Reef Early Warning System

    NASA Technical Reports Server (NTRS)

    Estep, Leland; Spruce, Joseph P.

    2007-01-01

    This RPC (Rapid Prototyping Capability) experiment will demonstrate the use of VIIRS (Visible/Infrared Imager/Radiometer Suite) and LDCM (Landsat Data Continuity Mission) sensor data as significant input to the NOAA (National Oceanic and Atmospheric Administration) ICON/ CREWS (Integrated Coral Reef Observation System/Coral Reef Early Warning System). The project affects the Coastal Management Program Element of the Applied Sciences Program.

  2. THE CONDITION OF CORAL REEFS IN SOUTH FLORIDA (2000) USING CORAL DISEASE AND BLEACHING AS INDICATORS

    EPA Science Inventory

    The destruction for coral reef habitats is occurring at unprecedented levels. Coral disease epizootics in the Southwestern Atlantic have lead to coral replacement by turf algae, prompting a call to classify some coral species as endangered. In addition, a massive bleaching event ...

  3. Devising a Coral Reef Ocean Acidification Monitoring Portfolio

    NASA Astrophysics Data System (ADS)

    Gledhill, D. K.; Jewett, L.

    2012-12-01

    Coral reef monitoring has frequently been based only on descriptive science with limited capacity to assign specific attribution to agents of change. There is a requirement to engineer a diagnostic monitoring approach that can test predictions regarding the response of coral reef ecosystems to ocean acidification, and to identify potential areas of refugia or areas of particular concern. The approach should provide the means to detect not only changes in water chemistry but also changes in coral reef community structure and function which can be anticipated based upon our current understanding of paleo-OA events, experimental findings, process investigations, and modeling projections In August, 2012 a Coral Reef Ocean Acidification Monitoring Portfolio Workshop was hosted by the NOAA Ocean Acidification Program and the National Coral Reef Institute at the Nova Southeastern University Oceanographic Center. The workshop convened researchers and project managers from around the world engaged in coral reef ecosystems ocean acidification monitoring and research. The workshop sought to define a suite of metrics to include as part of long-term coral reef monitoring efforts that can contribute to discerning specific attribution of changes in coral reef ecosystems in response to ocean acidification. This portfolio of observations should leverage existing and proposed monitoring initiatives and would be derived from a suite of chemical, biogeochemical and ecological measurements. This talk will report out on the key findings from the workshop which should include identifying the most valuable that should be integrated into long-term coral reef ecosystem monitoring that will aid in discerning changes in coral reef ecosystems in response to ocean acidification. The outcomes should provide: recommendations of the most efficient and robust ways to monitor these metrics; identified augmentations that would be required to current ocean acidification monitoring necessary to achieve

  4. Reply to comment by E. Bard et al. on "Younger Dryas sea level and meltwater pulse 1B recorded in Barbados reef crest coral Acropora palmata" by N. A. Abdul et al.

    NASA Astrophysics Data System (ADS)

    Mortlock, Richard A.; Abdul, Nicole A.; Wright, James D.; Fairbanks, Richard G.

    2016-12-01

    Abdul et al. (2016) presented a detailed record of sea level at Barbados (13.9-9 kyr B.P.) tightly constraining the timing and amplitude during the Younger Dryas and Meltwater Pulse 1B (MWP-1B) based on U-Th dated reef crest coral species Acropora palmata. The Younger Dryas slow stand and the large (14 m) rapid sea level jump are not resolved in the Tahiti record. Tahiti sea level estimates are remarkably close to the Barbados sea level curve between 13.9 and 11.6 kyr but fall below the Barbados sea level curve for a few thousand years following MWP-1B. By 9 kyr the Tahiti sea level estimates again converge with the Barbados sea level curve. Abdul et al. (2016) concluded that Tahiti reefs at the core sites did not keep up with intervals of rapidly rising sea level during MWP-1B. We counter Bard et al. (2016) by showing (1) that there is no evidence for a hypothetical fault in Oistins Bay affecting one of the Barbados coring locations, (2) that the authors confuse the rare occurrences of A. palmata at depths >5 m with the "thickets" of A. palmata fronds representing the reef-crest facies, and (3) that uncertainties in depth habitat proxies largely account for differences in Barbados and Tahiti sea level differences curves with A. palmata providing the most faithful proxy. Given the range in Tahiti paleodepth uncertainties at the cored sites, the most parsimonious explanation remains that Tahiti coralgal ridges did not keep up with the sea level rise of MWP-1B.

  5. Drivers and predictions of coral reef carbonate budget trajectories

    PubMed Central

    Graham, Nicholas A. J.; Jennings, Simon; Perry, Chris T.

    2017-01-01

    Climate change is one of the greatest threats to the long-term maintenance of coral-dominated tropical ecosystems, and has received considerable attention over the past two decades. Coral bleaching and associated mortality events, which are predicted to become more frequent and intense, can alter the balance of different elements that are responsible for coral reef growth and maintenance. The geomorphic impacts of coral mass mortality have received relatively little attention, particularly questions concerning temporal recovery of reef carbonate production and the factors that promote resilience of reef growth potential. Here, we track the biological carbonate budgets of inner Seychelles reefs from 1994 to 2014, spanning the 1998 global bleaching event when these reefs lost more than 90% of coral cover. All 21 reefs had positive budgets in 1994, but in 2005 budgets were predominantly negative. By 2014, carbonate budgets on seven reefs were comparable with 1994, but on all reefs where an ecological regime shift to macroalgal dominance occurred, budgets remained negative through 2014. Reefs with higher massive coral cover, lower macroalgae cover and lower excavating parrotfish biomass in 1994 were more likely to have positive budgets post-bleaching. If mortality of corals from the 2016 bleaching event is as severe as that of 1998, our predictions based on past trends would suggest that six of eight reefs with positive budgets in 2014 would still have positive budgets by 2030. Our results highlight that reef accretion and framework maintenance cannot be assumed from the ecological state alone, and that managers should focus on conserving aspects of coral reefs that support resilient carbonate budgets. PMID:28123092

  6. Drivers and predictions of coral reef carbonate budget trajectories.

    PubMed

    Januchowski-Hartley, Fraser A; Graham, Nicholas A J; Wilson, Shaun K; Jennings, Simon; Perry, Chris T

    2017-01-25

    Climate change is one of the greatest threats to the long-term maintenance of coral-dominated tropical ecosystems, and has received considerable attention over the past two decades. Coral bleaching and associated mortality events, which are predicted to become more frequent and intense, can alter the balance of different elements that are responsible for coral reef growth and maintenance. The geomorphic impacts of coral mass mortality have received relatively little attention, particularly questions concerning temporal recovery of reef carbonate production and the factors that promote resilience of reef growth potential. Here, we track the biological carbonate budgets of inner Seychelles reefs from 1994 to 2014, spanning the 1998 global bleaching event when these reefs lost more than 90% of coral cover. All 21 reefs had positive budgets in 1994, but in 2005 budgets were predominantly negative. By 2014, carbonate budgets on seven reefs were comparable with 1994, but on all reefs where an ecological regime shift to macroalgal dominance occurred, budgets remained negative through 2014. Reefs with higher massive coral cover, lower macroalgae cover and lower excavating parrotfish biomass in 1994 were more likely to have positive budgets post-bleaching. If mortality of corals from the 2016 bleaching event is as severe as that of 1998, our predictions based on past trends would suggest that six of eight reefs with positive budgets in 2014 would still have positive budgets by 2030. Our results highlight that reef accretion and framework maintenance cannot be assumed from the ecological state alone, and that managers should focus on conserving aspects of coral reefs that support resilient carbonate budgets.

  7. Could some coral reefs become sponge reefs as our climate changes?

    PubMed

    Bell, James J; Davy, Simon K; Jones, Timothy; Taylor, Michael W; Webster, Nicole S

    2013-09-01

    Coral reefs across the world have been seriously degraded and have a bleak future in response to predicted global warming and ocean acidification (OA). However, this is not the first time that biocalcifying organisms, including corals, have faced the threat of extinction. The end-Triassic mass extinction (200 million years ago) was the most severe biotic crisis experienced by modern marine invertebrates, which selected against biocalcifiers; this was followed by the proliferation of another invertebrate group, sponges. The duration of this sponge-dominated period far surpasses that of alternative stable-ecosystem or phase-shift states reported on modern day coral reefs and, as such, a shift to sponge-dominated reefs warrants serious consideration as one future trajectory of coral reefs. We hypothesise that some coral reefs of today may become sponge reefs in the future, as sponges and corals respond differently to changing ocean chemistry and environmental conditions. To support this hypothesis, we discuss: (i) the presence of sponge reefs in the geological record; (ii) reported shifts from coral- to sponge-dominated systems; and (iii) direct and indirect responses of the sponge holobiont and its constituent parts (host and symbionts) to changes in temperature and pH. Based on this evidence, we propose that sponges may be one group to benefit from projected climate change and ocean acidification scenarios, and that increased sponge abundance represents a possible future trajectory for some coral reefs, which would have important implications for overall reef functioning.

  8. 76 FR 38618 - Proposed Information Collection; Comment Request; Coral Reef Conservation Program Survey

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ... National Oceanic and Atmospheric Administration Proposed Information Collection; Comment Request; Coral... United States (U.S.) jurisdictions containing coral reefs. Specifically, NOAA is seeking information on... collection of social and economic data related to the communities affected by coral reef...

  9. Comparative studies on the status of Indonesian coral reefs

    NASA Astrophysics Data System (ADS)

    Soekarno, R.

    Coral reefs are of great economic importance for Indonesia. Unfortunately these resources are suffering from increasing human pressure. Several factors may cause the degradation of coral reefs, including the consequences of several human activities. Activities indirectly affecting the quality of the reefs are land-based activities such as deforestation, agriculture intensification, industrialization and domestic waste disposal. Direct use of the reefs, e.g. by coral mining, fish blasting and other fishing and collecting activities, is of greater and more widespread importance. Therefore, a rational management of the reef resources is urgently needed. Management is impossible without simple means of monitoring the status of reefs. One factor, living coral cover, has been determined for several years in many areas, including those studied during the Snellius-II Expedition. This allowed a comparative study of several different areas, which showed that coral cover is often very useful as an indication of the quality of reefs. It was found that the diversity of reef fishes is correlated with the condition of reefs as determined by the percentage cover of living coral.

  10. Topography and biological noise determine acoustic detectability on coral reefs

    NASA Astrophysics Data System (ADS)

    Cagua, E. F.; Berumen, M. L.; Tyler, E. H. M.

    2013-12-01

    Acoustic telemetry is an increasingly common tool for studying the movement patterns, behavior and site fidelity of marine organisms, but to accurately interpret acoustic data, the variability, periodicity and range of detectability between acoustic tags and receivers must be understood. The relative and interactive effects of topography with biological and environmental noise have not been quantified on coral reefs. We conduct two long-term range tests (1- and 4-month duration) on two different reef types in the central Red Sea to determine the relative effect of distance, depth, topography, time of day, wind, lunar phase, sea surface temperature and thermocline on detection probability. Detectability, as expected, declines with increasing distance between tags and receivers, and we find average detection ranges of 530 and 120 m, using V16 and V13 tags, respectively, but the topography of the reef can significantly modify this relationship, reducing the range by ~70 %, even when tags and receivers are in line-of-sight. Analyses that assume a relationship between distance and detections must therefore be used with care. Nighttime detection range was consistently reduced in both locations, and detections varied by lunar phase in the 4-month test, suggesting a strong influence of biological noise (reducing detection probability up to 30 %), notably more influential than other environmental noises, including wind-driven noise, which is normally considered important in open-water environments. Analysis of detections should be corrected in consideration of the diel patterns we find, and range tests or sentinel tags should be used for more than 1 month to quantify potential changes due to lunar phase. Some studies assume that the most usual factor limiting detection range is weather-related noise; this cannot be extrapolated to coral reefs.

  11. Functional versatility supports coral reef biodiversity

    PubMed Central

    Bellwood, D.R; Wainwright, P.C; Fulton, C.J; Hoey, A.S

    2005-01-01

    We explore the role of specialization in supporting species coexistence in high-diversity ecosystems. Using a novel ordination-based method to quantify specialist and generalist feeding structures and diets we examined the relationship between morphology and diet in 120 wrasses and parrotfishes from the Great Barrier Reef. We find that wrasses, despite their morphological diversity, exhibit weak links between morphology and diet and that specialist morphologies do not necessarily equate to specialized diets. The dominant pattern shows extensive overlap in morphology (functional morphospace occupation) among trophic groups; fish with a given morphology may have a number of feeding modes. Such trophic versatility may lay the foundation for both the origins and maintenance of high biodiversity on coral reefs. PMID:16519241

  12. Functional versatility supports coral reef biodiversity.

    PubMed

    Bellwood, D R; Wainwright, P C; Fulton, C J; Hoey, A S

    2006-01-07

    We explore the role of specialization in supporting species coexistence in high-diversity ecosystems. Using a novel ordination-based method to quantify specialist and generalist feeding structures and diets we examined the relationship between morphology and diet in 120 wrasses and parrotfishes from the Great Barrier Reef. We find that wrasses, despite their morphological diversity, exhibit weak links between morphology and diet and that specialist morphologies do not necessarily equate to specialized diets. The dominant pattern shows extensive overlap in morphology (functional morphospace occupation) among trophic groups; fish with a given morphology may have a number of feeding modes. Such trophic versatility may lay the foundation for both the origins and maintenance of high biodiversity on coral reefs.

  13. Status and changing patterns on coral reefs in Thailand during the last two decades

    NASA Astrophysics Data System (ADS)

    Phongsuwan, Niphon; Chankong, Anchalee; Yamarunpatthana, Chaimongkol; Chansang, Hansa; Boonprakob, Ronnawon; Petchkumnerd, Padorn; Thongtham, Nalinee; Paokantha, Sathika; Chanmethakul, Thanongsak; Panchaiyapoom, Paitoon; Bundit, On-Anong

    2013-11-01

    A long-term survey on monitoring coral reef status using the Manta-tow technique has been carried out over approximately two decades in Thailand. This paper presents results of the survey from three off-shore areas (north, central and south) in the Andaman Sea (since 1988) and from the two near-shore areas and one off-shore area in the Gulf of Thailand (GoT, since 1995). The results revealed variations in the change of live coral cover over time between different locations. Natural and direct/indirect man-made disturbances have influenced these changes. Until early 2010, reefs in the Andaman Sea were in better condition than those in the Gulf of Thailand. The coral bleaching in mid-2010, however, greatly impacted many reefs both seas. The northern off-shore area in the Andaman Sea showed the most damage, while reefs in the lower west of the Gulf of Thailand were least affected. Long-term monitoring of changes on reefs subjected to different environmental factors and human pressures is essential for the understanding and prediction of reef recovery in the face of climate change.

  14. A trophic model of fringing coral reefs in Nanwan Bay, southern Taiwan suggests overfishing.

    PubMed

    Liu, Pi-Jen; Shao, Kwang-Tsao; Jan, Rong-Quen; Fan, Tung-Yung; Wong, Saou-Lien; Hwang, Jiang-Shiou; Chen, Jen-Ping; Chen, Chung-Chi; Lin, Hsing-Juh

    2009-09-01

    Several coral reefs of Nanwan Bay, Taiwan have recently undergone shifts to macroalgal or sea anemone dominance. Thus, a mass-balance trophic model was constructed to analyze the structure and functioning of the food web. The fringing reef model was comprised of 18 compartments, with the highest trophic level of 3.45 for piscivorous fish. Comparative analyses with other reef models demonstrated that Nanwan Bay was similar to reefs with high fishery catches. While coral biomass was not lower, fish biomass was lower than those of reefs with high catches. Consequently, the sums of consumption and respiratory flows and total system throughput were also decreased. The Nanwan Bay model potentially suggests an overfished status in which the mean trophic level of the catch, matter cycling, and trophic transfer efficiency are extremely reduced.

  15. Do tabular corals constitute keystone structures for fishes on coral reefs?

    NASA Astrophysics Data System (ADS)

    Kerry, J. T.; Bellwood, D. R.

    2015-03-01

    This study examined the changes in community composition of reef fishes by experimentally manipulating the availability of shelter provided by tabular structures on a mid-shelf reef on the Great Barrier Reef. At locations where access to tabular corals ( Acropora hyacinthus and Acropora cytherea) was excluded, a rapid and sustained reduction in the abundance of large reef fishes occurred. At locations where tabular structure was added, the abundance and diversity of large reef fishes increased and the abundance of small reef fishes tended to decrease, although over a longer time frame. Based on their response to changes in the availability of tabular structures, nine families of large reef fishes were separated into three categories; designated as obligate, facultative or non-structure users. This relationship may relate to the particular ecological demands of each family, including avoidance of predation and ultraviolet radiation, access to feeding areas and reef navigation. This study highlights the importance of tabular corals for large reef fishes in shallow reef environments and provides a possible mechanism for local changes in the abundance of reef fishes following loss of structural complexity on coral reefs. Keystone structures have a distinct structure and disproportionate effect on their ecosystem relative to their abundance, as such the result of this study suggests tabular corals may constitute keystone structures on shallow coral reefs.

  16. 75 FR 39917 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Coral and Coral Reefs off the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-13

    ..., and South Atlantic; Coral and Coral Reefs off the Southern Atlantic States; Exempted Fishing Permit..., limited numbers of gorgonian corals from Federal waters, off the coast of North Carolina. The specimens... for Coral, Coral Reefs, and Live/Hardbottom Habitat of the South Atlantic Region. The applicant...

  17. 76 FR 30110 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Coral and Coral Reefs Off the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ..., and South Atlantic; Coral and Coral Reefs Off the Southern Atlantic States; Exempted Fishing Permit... limited numbers of gorgonian corals from the exclusive economic zone (EEZ), off Port Canaveral, FL, north... implementing the Fishery Management Plan for Coral, Coral Reefs, and Live/Hardbottom Habitat of the...

  18. A demographic approach to monitoring the health of coral reefs.

    PubMed

    Smith, L D; Devlin, M; Haynes, D; Gilmour, J P

    2005-01-01

    Inshore coral reefs adjacent to the wet tropics in North Queensland, Australia, are regularly exposed to flood plumes from coastal river systems. Changes in the nature of these plumes have been linked to the declining health of coral reefs in the region. The effect of flood plumes on the health of inshore corals was investigated by quantifying aspects of the demography of populations of corymbose and digitate Acropora at three groups of Island reefs along a gradient of exposure and decreasing water quality (High Island >Frankland's >Fitzroy). The size-structures of colonies, the rates of sexual recruitment, and the growth and survival of juveniles, all varied among the Island reefs. Juvenile and adult sized colonies were far more abundant at the Fitzroy Island reefs, than at the High or Frankland Island reefs that were more exposed to flood plumes. Additionally, there were up to eight times as many sexual recruits at the Fitzroy Island reefs, compared with the High Island reefs. However, the rates of growth and survival of the juvenile sized corals at the Fitzroy Island reefs were lower than at the more exposed reefs. The comparatively low abundance of adult corals at the exposed reefs is most likely due to their histories of disturbance from crown-of-thorns and coral bleaching, but the lack of subsequent recovery due to their low levels of larval recruitment. If a stock-recruitment relationship is typical for these groups of reefs, then the low rates of recruitment may be linked to the low density of adult colonies. Alternately, direct or indirect effects of chronic exposure to poor water quality may have resulted in less suitable substrata for larval settlement. We discuss these results and provide examples of how information about population structure and dynamics can be used in simple matrix models to quantify the current and future health of populations of corals under various scenarios.

  19. Multi-site evaluation of IKONOS data for classification of tropical coral reef environments

    USGS Publications Warehouse

    Andrefouet, S.; Kramer, Philip; Torres-Pulliza, D.; Joyce, K.E.; Hochberg, E.J.; Garza-Perez, R.; Mumby, P.J.; Riegl, Bernhard; Yamano, H.; White, W.H.; Zubia, M.; Brock, J.C.; Phinn, S.R.; Naseer, A.; Hatcher, B.G.; Muller-Karger, F. E.

    2003-01-01

    Ten IKONOS images of different coral reef sites distributed around the world were processed to assess the potential of 4-m resolution multispectral data for coral reef habitat mapping. Complexity of reef environments, established by field observation, ranged from 3 to 15 classes of benthic habitats containing various combinations of sediments, carbonate pavement, seagrass, algae, and corals in different geomorphologic zones (forereef, lagoon, patch reef, reef flats). Processing included corrections for sea surface roughness and bathymetry, unsupervised or supervised classification, and accuracy assessment based on ground-truth data. IKONOS classification results were compared with classified Landsat 7 imagery for simple to moderate complexity of reef habitats (5-11 classes). For both sensors, overall accuracies of the classifications show a general linear trend of decreasing accuracy with increasing habitat complexity. The IKONOS sensor performed better, with a 15-20% improvement in accuracy compared to Landsat. For IKONOS, overall accuracy was 77% for 4-5 classes, 71% for 7-8 classes, 65% in 9-11 classes, and 53% for more than 13 classes. The Landsat classification accuracy was systematically lower, with an average of 56% for 5-10 classes. Within this general trend, inter-site comparisons and specificities demonstrate the benefits of different approaches. Pre-segmentation of the different geomorphologic zones and depth correction provided different advantages in different environments. Our results help guide scientists and managers in applying IKONOS-class data for coral reef mapping applications. ?? 2003 Elsevier Inc. All rights reserved.

  20. Sediment suppresses herbivory across a coral reef depth gradient.

    PubMed

    Goatley, Christopher H R; Bellwood, David R

    2012-12-23

    Sediments are a ubiquitous feature of all coral reefs, yet our understanding of how they affect complex ecological processes on coral reefs is limited. Sediment in algal turfs has been shown to suppress herbivory by coral reef fishes on high-sediment, low-herbivory reef flats. Here, we investigate the role of sediment in suppressing herbivory across a depth gradient (reef base, crest and flat) by observing fish feeding following benthic sediment reductions. We found that sediment suppresses herbivory across all reef zones. Even slight reductions on the reef crest, which has 35 times less sediment than the reef flat, resulted in over 1800 more herbivore bites (h(-1) m(-2)). The Acanthuridae (surgeonfishes) were responsible for over 80 per cent of all bites observed, and on the reef crest and flat took over 1500 more bites (h(-1) m(-2)) when sediment load was reduced. These findings highlight the role of natural sediment loads in shaping coral reef herbivory and suggest that changes in benthic sediment loads could directly impair reef resilience.

  1. Unseen players shape benthic competition on coral reefs.

    PubMed

    Barott, Katie L; Rohwer, Forest L

    2012-12-01

    Recent work has shown that hydrophilic and hydrophobic organic matter (OM) from algae disrupts the function of the coral holobiont and promotes the invasion of opportunistic pathogens, leading to coral morbidity and mortality. Here we refer to these dynamics as the (3)DAM [dissolved organic matter (DOM), direct contact, disease, algae and microbes] model. There is considerable complexity in coral-algae interactions; turf algae and macroalgae promote heterotrophic microbial overgrowth of coral, macroalgae also directly harm the corals via hydrophobic OM, whereas crustose coralline algae generally encourage benign microbial communities. In addition, complex flow patterns transport OM and pathogens from algae to downstream corals, and direct algal contact enhances their delivery. These invisible players (microbes, viruses, and OM) are important drivers of coral reefs because they have non-linear responses to disturbances and are the first to change in response to perturbations, providing near real-time trajectories for a coral reef, a vital metric for conservation and restoration.

  2. Status and conservation of coral reefs in Costa Rica.

    PubMed

    Cortés, Jorge; Jiménez, Carlos E; Fonseca, Ana C; Alvarado, Juan José

    2010-05-01

    Costa Rica has coral communities and reefs on the Caribbean coast and on the Pacific along the coast and off-shore islands. The Southern section of the Caribbean coast has fringing and patch reefs, carbonate banks, and an incipient algal ridge. The Pacific coast has coral communities, reefs and isolated coral colonies. Coral reefs have been seriously impacted in the last 30 years, mainly by sediments (Caribbean coast and some Pacific reefs) and by El Niño warming events (both coasts). Monitoring is being carried out at three sites on each coast. Both coasts suffered significant reductions in live coral cover in the 1980's, but coral cover is now increasing in most sites. The government of Costa Rica is aware of the importance of coral reefs and marine environments in general, and in recent years decrees have been implemented (or are in the process of approval) to protect them, but limited resources endanger their proper management and conservation, including proper outreach to reef users and the general public.

  3. Macroalgal terpenes function as allelopathic agents against reef corals.

    PubMed

    Rasher, Douglas B; Stout, E Paige; Engel, Sebastian; Kubanek, Julia; Hay, Mark E

    2011-10-25

    During recent decades, many tropical reefs have transitioned from coral to macroalgal dominance. These community shifts increase the frequency of algal-coral interactions and may suppress coral recovery following both anthropogenic and natural disturbance. However, the extent to which macroalgae damage corals directly, the mechanisms involved, and the species specificity of algal-coral interactions remain uncertain. Here, we conducted field experiments demonstrating that numerous macroalgae directly damage corals by transfer of hydrophobic allelochemicals present on algal surfaces. These hydrophobic compounds caused bleaching, decreased photosynthesis, and occasionally death of corals in 79% of the 24 interactions assayed (three corals and eight algae). Coral damage generally was limited to sites of algal contact, but algae were unaffected by contact with corals. Artificial mimics for shading and abrasion produced no impact on corals, and effects of hydrophobic surface extracts from macroalgae paralleled effects of whole algae; both findings suggest that local effects are generated by allelochemical rather than physical mechanisms. Rankings of macroalgae from most to least allelopathic were similar across the three coral genera tested. However, corals varied markedly in susceptibility to allelopathic algae, with globally declining corals such as Acropora more strongly affected. Bioassay-guided fractionation of extracts from two allelopathic algae led to identification of two loliolide derivatives from the red alga Galaxaura filamentosa and two acetylated diterpenes from the green alga Chlorodesmis fastigiata as potent allelochemicals. Our results highlight a newly demonstrated but potentially widespread competitive mechanism to help explain the lack of coral recovery on many present-day reefs.

  4. Bridging the Reef gaps: first evidence for corals surviving under low pH conditions

    NASA Astrophysics Data System (ADS)

    Tchernov, D.; Fine, M.

    2007-12-01

    Following two major extinction events, the late Permian and Triassic/Jurassic, there is a long absence of corals from the geological record followed by a recurrence coral fossils. This unusual disappearance and reappearance, referred to commonly as 'reef gaps', was explained as a failure in sampling effort, and/or the movement of these species into geographic 'refugia' that have not been found. Because the phylogeny of recent corals suggests their origin in the pre-Permian-extinction , an alternative explanation for reef gaps hypothesized that corals have a means of alternating between soft bodies and fossilizing forms. This study supports this hypothesis. Thirty coral fragments from 5 coral colonies of the scleractinian Mediterranean corals Oculina patagonica (encrusting) and Madracis pharencis (bulbous) were subjected to pH 7.4-7.6 (in accordance with the pH projected by the IPCC for the year 2300) and 30 fragments to pH 8.0-8.3 (ambient) over a period of 12 months. 100% of the colonies in the experiment and 90% of all polyps survived to the end the experiment. The corals grown in acidified conditions, where skeleton-building conditions were absent, maintained basic life functions as a solitary skeleton-less ecophenotype resembling a sea anemone. On an evolutionary scale, these results provide a possible explanation to coral survival over major extinction events such as the Permian/Triassic and Triassic/Jurassic events. It is important to note that these results only demonstrate that corals can persist as soft bodied ecophoenotypes, but the loss of reef framework has major ramifications to the entire structure and function of coral reef ecosystems, ultimately impacting the services they provide to human society.

  5. Responses of coral reef fishes to past climate changes are related to life-history traits.

    PubMed

    Ottimofiore, Eduardo; Albouy, Camille; Leprieur, Fabien; Descombes, Patrice; Kulbicki, Michel; Mouillot, David; Parravicini, Valeriano; Pellissier, Loïc

    2017-03-01

    Coral reefs and their associated fauna are largely impacted by ongoing climate change. Unravelling species responses to past climatic variations might provide clues on the consequence of ongoing changes. Here, we tested the relationship between changes in sea surface temperature and sea levels during the Quaternary and present-day distributions of coral reef fish species. We investigated whether species-specific responses are associated with life-history traits. We collected a database of coral reef fish distribution together with life-history traits for the Indo-Pacific Ocean. We ran species distribution models (SDMs) on 3,725 tropical reef fish species using contemporary environmental factors together with a variable describing isolation from stable coral reef areas during the Quaternary. We quantified the variance explained independently by isolation from stable areas in the SDMs and related it to a set of species traits including body size and mobility. The variance purely explained by isolation from stable coral reef areas on the distribution of extant coral reef fish species largely varied across species. We observed a triangular relationship between the contribution of isolation from stable areas in the SDMs and body size. Species, whose distribution is more associated with historical changes, occurred predominantly in the Indo-Australian archipelago, where the mean size of fish assemblages is the lowest. Our results suggest that the legacy of habitat changes of the Quaternary is still detectable in the extant distribution of many fish species, especially those with small body size and the most sedentary. Because they were the least able to colonize distant habitats in the past, fish species with smaller body size might have the most pronounced lags in tracking ongoing climate change.

  6. The importance of the terrestrial weathering feedback for multimillennial coral reef habitat recovery

    NASA Astrophysics Data System (ADS)

    Meissner, Katrin J.; McNeil, Ben I.; Eby, Michael; Wiebe, Edward C.

    2012-09-01

    Modern-day coral reefs have well defined environmental envelopes for light, sea surface temperature (SST) and seawater aragonite saturation state (Ωarag). We examine the changes in global coral reef habitat on multimillennial timescales with regard to SST and Ωaragusing a climate model including a three-dimensional ocean general circulation model, a fully coupled carbon cycle, and six different parameterizations for continental weathering (the UVic Earth System Climate Model). The model is forced with emission scenarios ranging from 1,000 Pg C to 5,000 Pg C total emissions. We find that the long-term climate change response is independent of the rate at which CO2 is emitted over the next few centuries. On millennial timescales, the weathering feedback introduces a significant uncertainty even for low emission scenarios. Weathering parameterizations based on atmospheric CO2 only display a different transient response than weathering parameterizations that are dependent on temperature. Although environmental conditions for SST and Ωaragstay globally hostile for coral reefs for millennia for our high emission scenarios, some weathering parameterizations induce a near-complete recovery of coral reef habitat to current conditions after 10,000 years, while others result in a collapse of coral reef habitat throughout our simulations. We find that the multimillennial response in sea surface temperature (SST) substantially lags the aragonite saturation recovery in all configurations. This implies that if corals can naturally adapt over millennia by selecting thermally tolerant species to match warmer ocean temperatures, prospects for long-term recovery of coral reefs are better since Ωarag recovers more quickly than SST.

  7. Mean circulation of the Coral Sea

    NASA Astrophysics Data System (ADS)

    Kessler, William S.; Cravatte, Sophie

    2013-12-01

    The mean absolute geostrophic circulation of the Coral Sea is constructed from climatological hydrographic data referenced to a 1000 m velocity field derived from Argo float drift. Two branches of the South Equatorial Current (SEC) enter the Coral Sea between New Caledonia and the Solomon Islands: the broad, upper thermocline North Vanuatu Jet (NVJ), and the narrow North Caledonian Jet (NCJ) extending to at least 1500 m. Most of this incoming flow leaves to the Solomon Sea. Four distinct pathways through the Coral Sea are traced by their water properties: (1) The NCJ crosses the Sea to the coast of Australia and turns north at densities sigma 25-27.4 as the main source of the Gulf of Papua (GPC) western boundary current, eventually feeding the New Guinea Coastal Undercurrent; (2) part of the shallow NVJ turns into the Solomon Sea in midbasin, carrying high-salinity water above sigma 25.5; (3) another part of the NVJ continues to Australia, then turns north to join the GPC, extending it to the surface; (4) a shallow finger of NVJ water, traced by low oxygen above sigma 25, turns south along the coast, beginning the East Australian Current (EAC) at 15°S. Total transport from the Coral to the Tasman Sea is small and shallow; instead, most of the EAC is fed from south of New Caledonia, consistent with the Island Rule. However, large transport fractions occur in narrow jets close to coastlines and reefs and are not well sampled, precluding a quantitative estimate of meridional redistribution of the incoming SEC.

  8. Conservation Planning for Coral Reefs Accounting for Climate Warming Disturbances

    PubMed Central

    Magris, Rafael A.; Heron, Scott F.; Pressey, Robert L.

    2015-01-01

    Incorporating warming disturbances into the design of marine protected areas (MPAs) is fundamental to developing appropriate conservation actions that confer coral reef resilience. We propose an MPA design approach that includes spatially- and temporally-varying sea-surface temperature (SST) data, integrating both observed (1985–2009) and projected (2010–2099) time-series. We derived indices of acute (time under reduced ecosystem function following short-term events) and chronic thermal stress (rate of warming) and combined them to delineate thermal-stress regimes. Coral reefs located on the Brazilian coast were used as a case study because they are considered a conservation priority in the southwestern Atlantic Ocean. We show that all coral reef areas in Brazil have experienced and are projected to continue to experience chronic warming, while acute events are expected to increase in frequency and intensity. We formulated quantitative conservation objectives for regimes of thermal stress. Based on these objectives, we then evaluated if/how they are achieved in existing Brazilian MPAs and identified priority areas where additional protection would reinforce resilience. Our results show that, although the current system of MPAs incorporates locations within some of our thermal-stress regimes, historical and future thermal refugia along the central coast are completely unprotected. Our approach is applicable to other marine ecosystems and adds to previous marine planning for climate change in two ways: (i) by demonstrating how to spatially configure MPAs that meet conservation objectives for warming disturbance using spatially- and temporally-explicit data; and (ii) by strategically allocating different forms of spatial management (MPA types) intended to mitigate warming impacts and also enhance future resistance to climate warming. PMID:26535586

  9. Tourism's nitrogen footprint on a Mesoamerican coral reef

    NASA Astrophysics Data System (ADS)

    Baker, D. M.; Rodríguez-Martínez, R. E.; Fogel, M. L.

    2013-09-01

    Globally, the eutrophication of coastal marine environments is a worsening problem that is accelerating the loss of biodiversity and ecosystem services. Coral reefs are among the most sensitive to this change, as chronic inputs of agricultural and wastewater effluents and atmospheric deposition disrupt their naturally oligotrophic state. Often, anthropogenic alteration of the coastal nitrogen pool can proceed undetected as rapid mixing with ocean waters can mask chronic and ephemeral nitrogen inputs. Monitoring nitrogen stable isotope values ( δ 15N) of benthic organisms provides a useful solution to this problem. Through a 7-yr monitoring effort in Quintana Roo, Mexico, we show that δ 15N values of the common sea fan Gorgonia ventalina were more variable near a developed (Akumal) site than at an undeveloped (Mahahual) site. Beginning in 2007, the global recession decreased tourist visitations to Akumal, which corresponded with a pronounced 1.6 ‰ decline in sea fan δ 15N through 2009, at which time δ 15N values were similar to those from Mahahual. With the recovery of tourism, δ 15N values increased to previous levels. Overall, 84 % of the observed variation in δ 15N was explained by tourist visitations in the preceding year alone, indicating that variable nitrogen source contributions are correlated with sea fan δ 15N values. We also found that annual precipitation accounted for some variation in δ 15N, likely due to its role in groundwater flushing into the sea. Together, these factors accounted for 96 % of the variation in δ 15N. Using a mixing model, we estimate that sewage can account for up to 42 % of nitrogen in sea fan biomass. These findings illustrate the high connectivity between land-based activities and coral reef productivity and the measurable impact of the tourism industry on the ecosystem it relies on.

  10. Coral reef diseases in the Atlantic-Caribbean

    USGS Publications Warehouse

    Rogers, Caroline S.; Weil, Ernesto; Dubinsky, Zvy; Stambler, Noga

    2010-01-01

    Coral reefs are the jewels of the tropical oceans. They boast the highest diversity of all marine ecosystems, aid in the development and protection of other important, productive coastal marine communities, and have provided millions of people with food, building materials, protection from storms, recreation and social stability over thousands of years, and more recently, income, active pharmacological compounds and other benefits. These communities have been deteriorating rapidly in recent times. The continuous emergence of coral reef diseases and increase in bleaching events caused in part by high water temperatures among other factors underscore the need for intensive assessments of their ecological status and causes and their impact on coral reefs.

  11. Current status of coral reefs in the United Arab Emirates: Distribution, extent, and community structure with implications for management.

    PubMed

    Grizzle, Raymond E; Ward, Krystin M; AlShihi, Rashid M S; Burt, John A

    2016-04-30

    Coral reefs of the United Arab Emirates were once extensive, but have declined dramatically in recent decades. Marine management and policy have been hampered by outdated and inaccurate habitat maps and habitat quality information. We combined existing recent datasets with our newly mapped coral habitats to provide a current assessment of nation-wide extent, and performed quantitative surveys of communities at 23 sites to assess coral cover and composition. Over 132 km(2) of coral habitat was mapped, averaging 28.6 ± 3.8% live coral cover at surveyed sites. In the Arabian Gulf low cover, low richness Porites dominated communities characterized western Abu Dhabi, while reefs northeast of Abu Dhabi city generally contained higher richness and cover, and were dominated by merulinids (formerly faviids). Distinct communities occur in the Sea of Oman, where cover and richness were low. We provide management recommendations to enhance conservation of vulnerable coral reefs in the UAE.

  12. Variability in reef connectivity in the Coral Triangle

    NASA Astrophysics Data System (ADS)

    Thompson, D. M.; Kleypas, J. A.; Castruccio, F. S.; Watson, J. R.; Curchitser, E. N.

    2015-12-01

    The Coral Triangle (CT) is not only the global center of marine biodiversity, it also supports the livelihoods of millions of people. Unfortunately, it is also considered the most threatened of all reef regions, with rising temperature and coral bleaching already taking a toll. Reproductive connectivity between reefs plays a critical role in the reef's capacity to recover after such disturbances. Thus, oceanographic modeling efforts to understand patterns of reef connectivity are essential to the effective design of a network of Marine Protected Areas (MPAs) to conserve marine ecosystems in the Coral Triangle. Here, we combine a Regional Ocean Modeling System developed for the Coral Triangle (CT-ROMS) with a Lagrangian particle tracking tool (TRACMASS) to investigate the probability of coral larval transport between reefs. A 47-year hindcast simulation (1960-2006) was used to investigate the variability in larval transport of a broadcasting coral following mass spawning events in April and September. Potential connectivity between reefs was highly variable and stochastic from year to year, emphasizing the importance of decadal or longer simulations in identifying connectivity patterns, key source and sink regions, and thus marine management targets for MPAs. The influence of temperature on realized connectivity (future work) may add further uncertainty to year-to-year patterns of connectivity between reefs. Nonetheless, the potential connectivity results we present here suggest that although reefs in this region are primarily self-seeded, rare long-distance dispersal may promote recovery and genetic exchange between reefs in the region. The spatial pattern of "subpopulations" based solely on the physical drivers of connectivity between reefs closely match regional patterns of biodiversity, suggesting that physical barriers to larval dispersal may be a key driver of reef biodiversity. Finally, 21st Century simulations driven by the Community Earth System Model (CESM

  13. Linking social and ecological systems to sustain coral reef fisheries.

    PubMed

    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. Micro-topography mediates interactions between corals, algae, and herbivorous fishes on coral reefs

    NASA Astrophysics Data System (ADS)

    Brandl, S. J.; Hoey, A. S.; Bellwood, D. R.

    2014-06-01

    Processes occurring during the early life stages of corals are important for the replenishment of coral assemblages and the resilience of coral reefs. However, the factors influencing early life stages of corals are not well understood, and the role of micro-topographic complexity for habitat associations of juvenile corals is largely unexplored. This study investigated the microhabitat distribution patterns of early life stages of corals and a potential macroalgal competitor ( Turbinaria ornata) across two reef zones (reef crest and outer reef flat) on Lizard Island, Great Barrier Reef. In both reef zones, both corals and T. ornata were significantly more abundant in concealed microhabitats than in semi-concealed or open microhabitats (GLMM: P < 0.001). The prevalence of juvenile corals and T. ornata within concealed environments suggests that they might be effective refuges from grazing by herbivorous fishes. The density of juvenile corals was positively related, and density of T. ornata negatively related to the abundance of two groups of herbivorous fishes, pairing rabbitfishes, and surgeonfishes in the genus Zebrasoma (BEST ENV-BIO: r s = 0.72, P < 0.01), which feed in concealed microhabitats. This correlative evidence suggests that crevices may be important for early life stages of both coral and macroalgae, and that a specific suite of crevice-feeding fishes may influence benthic community dynamics in these microhabitats.

  15. Kenyan coral reef-associated gastropod assemblages: distribution and diversity patterns

    NASA Astrophysics Data System (ADS)

    McClanahan, T. R.

    1990-09-01

    A survey of Kenya's shallow water (<2 m) coral reef-associated prosobranch fauna was undertaken to determine patterns of distribution, density, diversity and species richness, and the possible role of other reef fauna and human utilization on these patterns. The sample assemblage of 135 species from 25 families is similar to other Indian Ocean regions with no apparent endemism or subregional faunal affinities. Species richness, determined by species-individual relationships, has been reduced by approximately 45% since the Pleistocene. Northern Kenya, typified by small coral islands experiencing river and estuarine discharges had low densities and species richness and high species variability. This is attributable to the interrelated factors of river discharge, small reefs and reduced predator refuge. Southern Kenya's more expansive fringing reef has a denser and richer fauna but appears less species rich than Tanzania. Variation within reefs suggests similarities in diversity between reef lagoons, flats and edges, but lagoons had lower densities than reef flat or edge sites. This is attributable to greater predation rates within lagoons. Species composition between reef locations was variable but differed for comparisons between reef lagoons and reef flats. The population densities of thirty commercially collected species were compared between shelled and unshelled reefs. Only two commercial strombids, Lambis truncata and L. chiragra, had lower densities within shelled compared to unshelled reefs. Within six southern Kenvan reef lagoons, total gastropod densities were negatively correlated with the Balistidae (triggerfish) and total fish densities and positively with sea urchin densities. The removal of balistids through fishing appears to lead to co-occurring population increases in gastropod and sea urchin populations which, in most instances, appears to negate the effect of shell collecting.

  16. Tracing carbon flow through coral reef food webs using a compound-specific stable isotope approach.

    PubMed

    McMahon, Kelton W; Thorrold, Simon R; Houghton, Leah A; Berumen, Michael L

    2016-03-01

    Coral reefs support spectacularly productive and diverse communities in tropical and sub-tropical waters throughout the world's oceans. Debate continues, however, on the degree to which reef biomass is supported by new water column production, benthic primary production, and recycled detrital carbon (C). We coupled compound-specific stable C isotope ratio (δ(13)C) analyses with Bayesian mixing models to quantify C flow from primary producers to coral reef fishes across multiple feeding guilds and trophic positions in the Red Sea. Analyses of reef fishes with putative diets composed primarily of zooplankton (Amblyglyphidodon indicus), benthic macroalgae (Stegastes nigricans), reef-associated detritus (Ctenochaetus striatus), and coral tissue (Chaetodon trifascialis) confirmed that δ(13)C values of essential amino acids from all baseline C sources were both isotopically diagnostic and accurately recorded in consumer tissues. While all four source end-members contributed to the production of coral reef fishes in our study, a single-source end-member often dominated dietary C assimilation of a given species, even for highly mobile, generalist top predators. Microbially reworked detritus was an important secondary C source for most species. Seascape configuration played an important role in structuring resource utilization patterns. For instance, Lutjanus ehrenbergii showed a significant shift from a benthic macroalgal food web on shelf reefs (71 ± 13 % of dietary C) to a phytoplankton-based food web (72 ± 11 %) on oceanic reefs. Our work provides insights into the roles that diverse C sources play in the structure and function of coral reef ecosystems and illustrates a powerful fingerprinting method to develop and test nutritional frameworks for understanding resource utilization.

  17. Phosphorus and nitrogen in coral reef sediments

    SciTech Connect

    Entsch, B.; Boto, K.G.; Sim, R.G.; Wellington, J.T.

    1983-05-01

    The occurrence of P and N in the sediments has been investigated on Davies Reef in the central region of the Great Barrier Reef Complex. Concentrations of inorganic P and N in the water were typical of nutrient-depleted tropical surface water. Carbonate sediments were found to contain a uniform pool of P (300 ppm by wt), principally in the form of inorganic phosphate. The interstitial water of the surface layer of sediment contained micromolar concentrations of inorganic P and even higher concentrations of inorganic N, principally as ammonium. These nutrient concentrations were considered too low to compete significantly with the uptake of available phasphate into algae. The presence of ammonium and soluble P was associated with anaerobic redox potentials in the sediments just below the surface. Soluble phosphorus was in equilibrium with a small, rapidly exchangeable fraction of the sedimentary pool of inorganic phosphate. Analyses of P in growing tips of Halimeda and corals (which supply more than half of reef sediments) suggested that the skeletons provide a biological mechanism for the replenishment of at least some of the sedimentary pool. Ratios of C:N:P for a selection of benthic algae were used as a preliminary indicator of thier N and P status.

  18. Defining the biological integrity of coral reefs using a biological condition gradient framework

    EPA Science Inventory

    Under authority of the Clean Water Act (CWA), the US EPA is committed to protecting the biological integrity of tropical ecosystems, including mangroves, seagrasses and coral reefs that lie within the 3-mile limit of the territorial seas. The biological condition gradient (BCG) w...

  19. Anthropogenic mortality on coral reefs in Caribbean Panama predates coral disease and bleaching.

    PubMed

    Cramer, Katie L; Jackson, Jeremy B C; Angioletti, Christopher V; Leonard-Pingel, Jill; Guilderson, Thomas P

    2012-06-01

    Caribbean reef corals have declined precipitously since the 1980s due to regional episodes of bleaching, disease and algal overgrowth, but the extent of earlier degradation due to localised historical disturbances such as land clearing and overfishing remains unresolved. We analysed coral and molluscan fossil assemblages from reefs near Bocas del Toro, Panama to construct a timeline of ecological change from the 19th century-present. We report large changes before 1960 in coastal lagoons coincident with extensive deforestation, and after 1960 on offshore reefs. Striking changes include the demise of previously dominant staghorn coral Acropora cervicornis and oyster Dendrostrea frons that lives attached to gorgonians and staghorn corals. Reductions in bivalve size and simplification of gastropod trophic structure further implicate increasing environmental stress on reefs. Our paleoecological data strongly support the hypothesis, from extensive qualitative data, that Caribbean reef degradation predates coral bleaching and disease outbreaks linked to anthropogenic climate change.

  20. Whole transcriptome analysis reveals changes in expression of immune-related genes during and after bleaching in a reef-building coral.

    PubMed

    Pinzón, Jorge H; Kamel, Bishoy; Burge, Colleen A; Harvell, C Drew; Medina, Mónica; Weil, Ernesto; Mydlarz, Laura D

    2015-04-01

    Climate change is negatively affecting the stability of natural ecosystems, especially coral reefs. The dissociation of the symbiosis between reef-building corals and their algal symbiont, or coral bleaching, has been linked to increased sea surface temperatures. Coral bleaching has significant impacts on corals, including an increase in disease outbreaks that can permanently change the entire reef ecosystem. Yet, little is known about the impacts of coral bleaching on the coral immune system. In this study, whole transcriptome analysis of the coral holobiont and each of the associate components (i.e. coral host, algal symbiont and other associated microorganisms) was used to determine changes in gene expression in corals affected by a natural bleaching event as well as during the recovery phase. The main findings include evidence that the coral holobiont and the coral host have different responses to bleaching, and the host immune system appears suppressed even a year after a bleaching event. These results support the hypothesis that coral bleaching changes the expression of innate immune genes of corals, and these effects can last even after recovery of symbiont populations. Research on the role of immunity on coral's resistance to stressors can help make informed predictions on the future of corals and coral reefs.

  1. Whole transcriptome analysis reveals changes in expression of immune-related genes during and after bleaching in a reef-building coral

    PubMed Central

    Pinzón, Jorge H.; Kamel, Bishoy; Burge, Colleen A.; Harvell, C. Drew; Medina, Mónica; Weil, Ernesto; Mydlarz, Laura D.

    2015-01-01

    Climate change is negatively affecting the stability of natural ecosystems, especially coral reefs. The dissociation of the symbiosis between reef-building corals and their algal symbiont, or coral bleaching, has been linked to increased sea surface temperatures. Coral bleaching has significant impacts on corals, including an increase in disease outbreaks that can permanently change the entire reef ecosystem. Yet, little is known about the impacts of coral bleaching on the coral immune system. In this study, whole transcriptome analysis of the coral holobiont and each of the associate components (i.e. coral host, algal symbiont and other associated microorganisms) was used to determine changes in gene expression in corals affected by a natural bleaching event as well as during the recovery phase. The main findings include evidence that the coral holobiont and the coral host have different responses to bleaching, and the host immune system appears suppressed even a year after a bleaching event. These results support the hypothesis that coral bleaching changes the expression of innate immune genes of corals, and these effects can last even after recovery of symbiont populations. Research on the role of immunity on coral's resistance to stressors can help make informed predictions on the future of corals and coral reefs. PMID:26064625

  2. Research Spotlight: New method to assess coral reef health

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-03-01

    Coral reefs around the world are becoming stressed due to rising temperatures, ocean acidification, overfishing, and other factors. Measuring community level rates of photosynthesis, respiration, and biogenic calcification is essential to assessing the health of coral reef ecosystems because the balance between these processes determines the potential for reef growth and the export of carbon. Measurements of biological productivity have typically been made by tracing changes in dissolved oxygen in seawater as it passes over a reef. However, this is a labor-intensive and difficult method, requiring repeated measurements. (Geophysical Research Letters, doi:10.1029/2010GL046179, 2011)

  3. Community structure and coral status across reef fishing intensity gradients in Palk Bay reef, southeast coast of India.

    PubMed

    Manikandan, B; Ravindran, J; Shrinivaasu, S; Marimuthu, N; Paramasivam, K

    2014-10-01

    Coral reef fishes are exploited without the knowledge of their sustainability and their possible effect in altering the community structure of a coral reef ecosystem. Alteration of the community structure could cause a decline in the health of coral reefs and its services. We documented the coral community structure, status of live corals and reef fish assemblages in Palk Bay at the reef fishing hotspots and its nearby reef area with minimum fishing pressure and compared it with a control reef area where reef fishing was banned for more than two decades. The comparison was based on the percent cover of different forms of live corals, their diversity and the density and diversity of reef fishes. The reef fish stock in the reef fishing hotspots and its neighbouring reef was lower by 61 and 38%, respectively compared to the control reef. The herbivore fish Scarus ghobban and Siganus javus were exploited at a rate of 250 and 105 kg month(-1) fishermen(-1), respectively, relatively high comparing the small reef area. Live and dead corals colonized by turf algae were predominant in both the reef fishing hotspots and its nearby coral ecosystems. The percent cover of healthy live corals and live corals colonized by turf algae was <10 and >80%, respectively, in the intensively fished coral ecosystems. The corals were less diverse and the massive Porites and Favia colonies were abundant in the intensive reef fishing sites. Results of this study suggest that the impact of reef fish exploitation was not solely restricted to the intensively fished reefs, but also to the nearby reefs which play a critical role in the resilience of degraded reef ecosystems.

  4. Coral Reef and Coastal Ecosystems Decision Support Workshop April 27-29, 2010 Caribbean Coral Reef Institute, La Parguera, Puerto Rico

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) and Caribbean Coral Reef Institute (CCRI) hosted a Coral Reef and Coastal Ecosystems Decision Support Workshop on April 27-28, 2010 at the Caribbean Coral Reef Institute in La Parguera, Puerto Rico. Forty-three participants, includin...

  5. Coastal Benthic Optical Properties (CoBOP) of Coral Reef Environments: Small Scale Fluorescent Optical Signatures and Hyperspectral Remote Sensing of Coral Reef Habitats

    DTIC Science & Technology

    2003-09-30

    and in particular, coral reefs. Coral reef communities are coastal areas of high water transparency which make them ideal systems to study optical...signatures originating from the benthos. The scientific objectives of my project are: 1. to attain optical closure for coral reef communities 2. to

  6. Resilience and climate change: lessons from coral reefs and bleaching in the Western Indian Ocean

    NASA Astrophysics Data System (ADS)

    Obura, David O.

    2005-05-01

    The impact of climate change through thermal stress-related coral bleaching on coral reefs of the Western Indian Ocean has been well documented and is caused by rising sea water temperatures associated with background warming trends and extreme climate events. Recent studies have identified a number of factors that may reduce the impact of coral bleaching and mortality at a reef or sub-reef level. However, there is little scientific consensus as yet, and it is unclear how well current science supports the immediate needs of management responses to climate change. This paper provides evidence from the Western Indian Ocean in support of recent hypotheses on coral and reef vulnerability to thermal stress that have been loosely termed 'resistance and resilience to bleaching'. The paper argues for a more explicit definition of terms, and identifies three concepts affecting coral-zooxanthellae holobiont and reef vulnerability to thermal stress previously termed 'resistance to bleaching': 'thermal protection', where some reefs are protected from the thermal conditions that induce bleaching and/or where local physical conditions reduce bleaching and mortality levels; 'thermal resistance', where individual corals bleach to differing degrees to the same thermal stress; and 'thermal tolerance', where individual corals suffer differing levels of mortality when exposed to the same thermal stress. 'Resilience to bleaching' is a special case of ecological resilience, where recovery following large-scale bleaching mortality varies according to ecological and other processes. These concepts apply across multiple levels of biological organization and temporal and spatial scales. Thermal resistance and tolerance are genetic properties and may interact with environmental protection properties resulting in phenotypic variation in bleaching and mortality of corals. The presence or absence of human threats and varying levels of reef management may alter the influence of the above factors

  7. Diverse staghorn coral fauna on the mesophotic reefs of north-east Australia.

    PubMed

    Muir, Paul; Wallace, Carden; Bridge, Tom C L; Bongaerts, Pim

    2015-01-01

    Concern for the future of reef-building corals in conditions of rising sea temperatures combined with recent technological advances has led to a renewed interest in documenting the biodiversity of mesophotic coral ecosystems (MCEs) and their potential to provide lineage continuation for coral taxa. Here, we examine species diversity of staghorn corals (genera Acropora and Isopora) in the mesophotic zone (below 30 m depth) of the Great Barrier Reef and western Coral Sea. Using specimen-based records we found 38 staghorn species in the mesophotic zone, including three species newly recorded for Australia and five species that only occurred below 30 m. Staghorn corals became scarce at depths below 50 m but were found growing in-situ to 73 m depth. Of the 76 staghorn coral species recorded for shallow waters (depth ≤ 30 m) in north-east Australia, 21% extended to mesophotic depths with a further 22% recorded only rarely to 40 m depth. Extending into the mesophotic zone provided shallow water species no significant advantage in terms of their estimated global range-size relative to species restricted to shallow waters (means 86.2 X 10(6) km2 and 85.7 X 10(6) km2 respectively, p = 0.98). We found four staghorn coral species at mesophotic depths on the Great Barrier Reef that were previously considered rare and endangered on the basis of their limited distribution in central Indonesia and the far western Pacific. Colonies below 40 m depth showed laterally flattened branches, light and fragile skeletal structure and increased spacing between branches and corallites. The morphological changes are discussed in relation to decreased light, water movement and down-welling coarse sediments. Staghorn corals have long been regarded as typical shallow-water genera, but here we demonstrate the significant contribution of this group to the region's mesophotic fauna and the importance of considering MCEs in reef biodiversity estimates and management.

  8. Diverse Staghorn Coral Fauna on the Mesophotic Reefs of North-East Australia

    PubMed Central

    Muir, Paul; Wallace, Carden; Bridge, Tom C. L.; Bongaerts, Pim

    2015-01-01

    Concern for the future of reef-building corals in conditions of rising sea temperatures combined with recent technological advances has led to a renewed interest in documenting the biodiversity of mesophotic coral ecosystems (MCEs) and their potential to provide lineage continuation for coral taxa. Here, we examine species diversity of staghorn corals (genera Acropora and Isopora) in the mesophotic zone (below 30 m depth) of the Great Barrier Reef and western Coral Sea. Using specimen-based records we found 38 staghorn species in the mesophotic zone, including three species newly recorded for Australia and five species that only occurred below 30 m. Staghorn corals became scarce at depths below 50 m but were found growing in-situ to 73 m depth. Of the 76 staghorn coral species recorded for shallow waters (depth ≤ 30 m) in north-east Australia, 21% extended to mesophotic depths with a further 22% recorded only rarely to 40 m depth. Extending into the mesophotic zone provided shallow water species no significant advantage in terms of their estimated global range-size relative to species restricted to shallow waters (means 86.2 X 106 km2 and 85.7 X 106 km2 respectively, p = 0.98). We found four staghorn coral species at mesophotic depths on the Great Barrier Reef that were previously considered rare and endangered on the basis of their limited distribution in central Indonesia and the far western Pacific. Colonies below 40 m depth showed laterally flattened branches, light and fragile skeletal structure and increased spacing between branches and corallites. The morphological changes are discussed in relation to decreased light, water movement and down-welling coarse sediments. Staghorn corals have long been regarded as typical shallow-water genera, but here we demonstrate the significant contribution of this group to the region’s mesophotic fauna and the importance of considering MCEs in reef biodiversity estimates and management. PMID:25714341

  9. 76 FR 68711 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ..., Queen Conch and Coral and Reef Associated Plants and Invertebrates Fishery Management Plans of Puerto... Puerto Rico and the U.S. Virgin Islands, and Amendment 3 to the FMP for Corals and Reef Associated Plants... framework procedures for the spiny lobster and Caribbean corals and reef associated plants and...

  10. Climate change and coral reefs: Trojan horse or false prophecy?

    NASA Astrophysics Data System (ADS)

    Hoegh-Guldberg, O.

    2009-09-01

    Maynard et al. (Coral Reefs 27:745-749, 2008a) claim that much of the concern about the impacts of climate change on coral reefs has been “based on essentially untested assumptions regarding reefs and their capacity to cope with future climate change”. If correct, this claim has important implications for whether or not climate change represents the largest long-term threat to the sustainability of coral reefs, especially given their ad hominem argument that many coral reef scientists are guilty of “popularising worst-case scenarios” at the expense of truth. This article looks critically at the claims made by Maynard et al. (Coral Reefs 27:745-749, 2008a) and comes to a very different conclusion, with the thrust and veracity of their argument being called into question. Contrary to the fears of Grigg (Coral Reefs 11:183-186, 1992), who originally made reference to the Cassandra syndrome due to his concern about the sensationalisation of science, the proposition that coral reefs face enormous challenges from climate change and ocean acidification has and is being established through “careful experimentation, long-term monitoring and objective interpretation”. While this is reassuring, coral reef ecosystems continue to face major challenges from ocean warming and acidification. Given this, it is an imperative that scientists continue to maintain the rigour of their research and to communicate their conclusions as widely and clearly as possible. Given the shortage of time and the magnitude of the problem, there is little time to spare.

  11. Ecological limitations to the resilience of coral reefs

    NASA Astrophysics Data System (ADS)

    Mora, Camilo; Graham, Nicholas A. J.; Nyström, Magnus

    2016-12-01

    The decline of coral reefs has been broadly attributed to human stressors being too strong and pervasive, whereas biological processes that may render coral reefs fragile have been sparsely considered. Here we review several ecological factors that can limit the ability of coral reefs to withstand disturbance. These include: (1) Many species lack the adaptive capacity to cope with the unprecedented disturbances they currently face; (2) human disturbances impact vulnerable life history stages, reducing reproductive output and the supply of recruits essential for recovery; (3) reefs can be vulnerable to the loss of few species, as niche specialization or temporal and spatial segregation makes each species unique (i.e., narrow ecological redundancy); in addition, many foundation species have similar sensitivity to disturbances, suggesting that entire functions can be lost to single disturbances; and (4) feedback loops and extinction vortices may stabilize degraded states or accelerate collapses even if stressors are removed. This review suggests that the degradation of coral reefs is due to not only the severity of human stressors but also the "fragility" of coral reefs. As such, appropriate governance is essential to manage stressors while being inclusive of ecological process and human uses across transnational scales. This is a considerable but necessary upgrade in current management if the integrity, and delivery of goods and services, of coral reefs is to be preserved.

  12. Low calcification in corals in the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-10-01

    Reef-building coral communities in the Great Barrier Reef—the world's largest coral reef—may now be calcifying at only about half the rate that they did during the 1970s, even though live coral cover may not have changed over the past 40 years, a new study finds. In recent decades, coral reefs around the world, home to large numbers of fish and other marine species, have been threatened by such human activities as pollution, overfishing, global warming, and ocean acidification; the latter affects ambient water chemistry and availability of calcium ions, which are critical for coral communities to calcify, build, and maintain reefs. Comparing data from reef surveys during the 1970s, 1980s, and 1990s with present-day (2009) measurements of calcification rates in One Tree Island, a coral reef covering 13 square kilometers in the southern part of the Great Barrier Reef, Silverman et al. show that the total calcification rates (the rate of calcification minus the rate of dissolution) in these coral communities have decreased by 44% over the past 40 years; the decrease appears to stem from a threefold reduction in calcification rates during nighttime.

  13. Ecological solutions to reef degradation: optimizing coral reef restoration in the Caribbean and Western Atlantic

    PubMed Central

    2016-01-01

    Reef restoration activities have proliferated in response to the need to mitigate coral declines and recover lost reef structure, function, and ecosystem services. Here, we describe the recent shift from costly and complex engineering solutions to recover degraded reef structure to more economical and efficient ecological approaches that focus on recovering the living components of reef communities. We review the adoption and expansion of the coral gardening framework in the Caribbean and Western Atlantic where practitioners now grow and outplant 10,000’s of corals onto degraded reefs each year. We detail the steps for establishing a gardening program as well as long-term goals and direct and indirect benefits of this approach in our region. With a strong scientific basis, coral gardening activities now contribute significantly to reef and species recovery, provide important scientific, education, and outreach opportunities, and offer alternate livelihoods to local stakeholders. While challenges still remain, the transition from engineering to ecological solutions for reef degradation has opened the field of coral reef restoration to a wider audience poised to contribute to reef conservation and recovery in regions where coral losses and recruitment bottlenecks hinder natural recovery. PMID:27781176

  14. Ecological solutions to reef degradation: optimizing coral reef restoration in the Caribbean and Western Atlantic.

    PubMed

    Lirman, Diego; Schopmeyer, Stephanie

    2016-01-01

    Reef restoration activities have proliferated in response to the need to mitigate coral declines and recover lost reef structure, function, and ecosystem services. Here, we describe the recent shift from costly and complex engineering solutions to recover degraded reef structure to more economical and efficient ecological approaches that focus on recovering the living components of reef communities. We review the adoption and expansion of the coral gardening framework in the Caribbean and Western Atlantic where practitioners now grow and outplant 10,000's of corals onto degraded reefs each year. We detail the steps for establishing a gardening program as well as long-term goals and direct and indirect benefits of this approach in our region. With a strong scientific basis, coral gardening activities now contribute significantly to reef and species recovery, provide important scientific, education, and outreach opportunities, and offer alternate livelihoods to local stakeholders. While challenges still remain, the transition from engineering to ecological solutions for reef degradation has opened the field of coral reef restoration to a wider audience poised to contribute to reef conservation and recovery in regions where coral losses and recruitment bottlenecks hinder natural recovery.

  15. The Power of Three: Coral Reefs, Seagrasses and Mangroves Protect Coastal Regions and Increase Their Resilience

    PubMed Central

    Guannel, Greg; Arkema, Katie; Ruggiero, Peter; Verutes, Gregory

    2016-01-01

    Natural habitats have the ability to protect coastal communities against the impacts of waves and storms, yet it is unclear how different habitats complement each other to reduce those impacts. Here, we investigate the individual and combined coastal protection services supplied by live corals on reefs, seagrass meadows, and mangrove forests during both non-storm and storm conditions, and under present and future sea-level conditions. Using idealized profiles of fringing and barrier reefs, we quantify the services supplied by these habitats using various metrics of inundation and erosion. We find that, together, live corals, seagrasses, and mangroves supply more protection services than any individual habitat or any combination of two habitats. Specifically, we find that, while mangroves are the most effective at protecting the coast under non-storm and storm conditions, live corals and seagrasses also moderate the impact of waves and storms, thereby further reducing the vulnerability of coastal regions. Also, in addition to structural differences, the amount of service supplied by habitats in our analysis is highly dependent on the geomorphic setting, habitat location and forcing conditions: live corals in the fringing reef profile supply more protection services than seagrasses; seagrasses in the barrier reef profile supply more protection services than live corals; and seagrasses, in our simulations, can even compensate for the long-term degradation of the barrier reef. Results of this study demonstrate the importance of taking integrated and place-based approaches when quantifying and managing for the coastal protection services supplied by ecosystems. PMID:27409584

  16. The Power of Three: Coral Reefs, Seagrasses and Mangroves Protect Coastal Regions and Increase Their Resilience.

    PubMed

    Guannel, Greg; Arkema, Katie; Ruggiero, Peter; Verutes, Gregory

    2016-01-01

    Natural habitats have the ability to protect coastal communities against the impacts of waves and storms, yet it is unclear how different habitats complement each other to reduce those impacts. Here, we investigate the individual and combined coastal protection services supplied by live corals on reefs, seagrass meadows, and mangrove forests during both non-storm and storm conditions, and under present and future sea-level conditions. Using idealized profiles of fringing and barrier reefs, we quantify the services supplied by these habitats using various metrics of inundation and erosion. We find that, together, live corals, seagrasses, and mangroves supply more protection services than any individual habitat or any combination of two habitats. Specifically, we find that, while mangroves are the most effective at protecting the coast under non-storm and storm conditions, live corals and seagrasses also moderate the impact of waves and storms, thereby further reducing the vulnerability of coastal regions. Also, in addition to structural differences, the amount of service supplied by habitats in our analysis is highly dependent on the geomorphic setting, habitat location and forcing conditions: live corals in the fringing reef profile supply more protection services than seagrasses; seagrasses in the barrier reef profile supply more protection services than live corals; and seagrasses, in our simulations, can even compensate for the long-term degradation of the barrier reef. Results of this study demonstrate the importance of taking integrated and place-based approaches when quantifying and managing for the coastal protection services supplied by ecosystems.

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

    PubMed

    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.

  18. Coral reef complexes at an atypical windward platform margin: Late Quaternary, southeast Florida

    USGS Publications Warehouse

    Lidz, B.H.

    2004-01-01

    Major coral reef complexes rim many modern and ancient carbonate platforms. Their role in margin evolution is not fully understood, particularly when they border a margin atypical of the classic model. Classic windward margins are steeply inclined. The windward margin of southeast Florida is distinct with a very low-gradient slope and a shelf edge ringed with 30-m-high Quaternary outlier reefs on a shallow upper-slope terrace. A newly developed synthesis of temporally well-constrained geologic events is used with surface and subsurface seismic-reflection contours to construct morphogenetic models of four discontinuous reef-complex sequences. The models show uneven subsurface topography, upward and landward buildups, and a previously unreported, rapid, Holocene progradation. The terms backstepped reef-complex margin, backfilled prograded margin, and coalesced reef-complex margin are proposed for sections exhibiting suitable signatures in the stratigraphic record. The models have significant implications for interpretation of ancient analogues. The Florida record chronicles four kinds of geologic events. (1) Thirteen transgressions high enough for marine deposition occurred between ca. 325 ka and the present. Six gave rise to stratigraphically successive coral reef complexes between ca. 185 and ca. 77.8 ka. The seventh reef ecosystem is Holocene. (2) Two primary coral reef architectures built the outer shelf and margin, producing respective ridge-and-swale and reef-and-trough geometries of very different scales. (3) Massive outlier reefs developed on an upper-slope terrace between ca. 106.5 and ca. 80 ka and are inferred to contain corals that would date to highstands at ca. 140 and 125 ka. (4) Sea level remained below elevation of the shelf between ca. 77.8 and ca. 9.6 ka. ?? 2004 Geological Society of America.

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    Since the early 1980s, episodes of coral reef bleaching and mortality, due primarily to climate-induced ocean warming, have occurred almost annually in one or more of the world's tropical or subtropical seas. Bleaching is episodic, with the most severe events typically accompanying coupled ocean-atmosphere phenomena, such as the El Niño-Southern Oscillation (ENSO), which result in sustained regional elevations of ocean temperature. Using this extended dataset (25+ years), we review the short- and long-term ecological impacts of coral bleaching on reef ecosystems, and quantitatively synthesize recovery data worldwide. Bleaching episodes have resulted in catastrophic loss of coral cover in some locations, and have changed coral community structure in many others, with a potentially critical influence on the maintenance of biodiversity in the marine tropics. Bleaching has also set the stage for other declines in reef health, such as increases in coral diseases, the breakdown of reef framework by bioeroders, and the loss of critical habitat for associated reef fishes and other biota. Secondary ecological effects, such as the concentration of predators on remnant surviving coral populations, have also accelerated the pace of decline in some areas. Although bleaching severity and recovery have been variable across all spatial scales, some reefs have experienced relatively rapid recovery from severe bleaching impacts. There has been a significant overall recovery of coral cover in the Indian Ocean, where many reefs were devastated by a single large bleaching event in 1998. In contrast, coral cover on western Atlantic reefs has generally continued to decline in response to multiple smaller bleaching events and a diverse set of chronic secondary stressors. No clear trends are apparent in the eastern Pacific, the central-southern-western Pacific or the Arabian Gulf, where some reefs are recovering and others are not. The majority of survivors and new recruits on

  20. Coral-associated bacterial communities on Ningaloo Reef, Western Australia.

    PubMed

    Ceh, Janja; Van Keulen, Mike; Bourne, David G

    2011-01-01

    Coral-associated microbial communities from three coral species (Pocillopora damicornis, Acropora tenuis and Favites abdita) were examined every 3 months (January, March, June, October) over a period of 1 year on Ningaloo Reef, Western Australia. Tissue from corals was collected throughout the year and additional sampling of coral mucus and seawater samples was performed in January. Tissue samples were also obtained in October from P. damicornis coral colonies on Rottnest Island off Perth, 1200 km south of Ningaloo Reef, to provide comparisons between coral-microbial associates in different locations. The community structures of the coral-associated microorganisms were analysed using phylogenetic analysis of 16S rRNA gene clone libraries, which demonstrated highly diverse microbial profiles among all the coral species sampled. Principal component analysis revealed that samples grouped according to time and not species, indicating that coral-microbial associations may be a result of environmental drivers such as oceanographic characteristics, benthic community structure and temperature. Tissue samples from P. damicornis at Rottnest Island revealed similarities in bacteria to the samples at Ningaloo Reef. This study highlights that coral-associated microbial communities are highly diverse; however, the complex interactions that determine the stability of these associations are not necessarily dependent on coral host specificity.

  1. Dynamic stability of coral reefs on the west Australian coast.

    PubMed

    Speed, Conrad W; Babcock, Russ C; Bancroft, Kevin P; Beckley, Lynnath E; Bellchambers, Lynda M; Depczynski, Martial; Field, Stuart N; Friedman, Kim J; Gilmour, James P; Hobbs, Jean-Paul A; Kobryn, Halina T; Moore, James A Y; Nutt, Christopher D; Shedrawi, George; Thomson, Damian P; Wilson, Shaun K

    2013-01-01

    Monitoring changes in coral cover and composition through space and time can provide insights to reef health and assist the focus of management and conservation efforts. We used a meta-analytical approach to assess coral cover data across latitudes 10-35°S along the west Australian coast, including 25 years of data from the Ningaloo region. Current estimates of coral cover ranged between 3 and 44% in coral habitats. Coral communities in the northern regions were dominated by corals from the families Acroporidae and Poritidae, which became less common at higher latitudes. At Ningaloo Reef coral cover has remained relatively stable through time (∼28%), although north-eastern and southern areas have experienced significant declines in overall cover. These declines are likely related to periodic disturbances such as cyclones and thermal anomalies, which were particularly noticeable around 1998/1999 and 2010/2011. Linear mixed effects models (LME) suggest latitude explains 10% of the deviance in coral cover through time at Ningaloo. Acroporidae has decreased in abundance relative to other common families at Ningaloo in the south, which might be related to persistence of more thermally and mechanically tolerant families. We identify regions where quantitative time-series data on coral cover and composition are lacking, particularly in north-western Australia. Standardising routine monitoring methods used by management and research agencies at these, and other locations, would allow a more robust assessment of coral condition and a better basis for conservation of coral reefs.

  2. Dynamic Stability of Coral Reefs on the West Australian Coast

    PubMed Central

    Speed, Conrad W.; Babcock, Russ C.; Bancroft, Kevin P.; Beckley, Lynnath E.; Bellchambers, Lynda M.; Depczynski, Martial; Field, Stuart N.; Friedman, Kim J.; Gilmour, James P.; Hobbs, Jean-Paul A.; Kobryn, Halina T.; Moore, James A. Y.; Nutt, Christopher D.; Shedrawi, George; Thomson, Damian P.; Wilson, Shaun K.

    2013-01-01

    Monitoring changes in coral cover and composition through space and time can provide insights to reef health and assist the focus of management and conservation efforts. We used a meta-analytical approach to assess coral cover data across latitudes 10–35°S along the west Australian coast, including 25 years of data from the Ningaloo region. Current estimates of coral cover ranged between 3 and 44% in coral habitats. Coral communities in the northern regions were dominated by corals from the families Acroporidae and Poritidae, which became less common at higher latitudes. At Ningaloo Reef coral cover has remained relatively stable through time (∼28%), although north-eastern and southern areas have experienced significant declines in overall cover. These declines are likely related to periodic disturbances such as cyclones and thermal anomalies, which were particularly noticeable around 1998/1999 and 2010/2011. Linear mixed effects models (LME) suggest latitude explains 10% of the deviance in coral cover through time at Ningaloo. Acroporidae has decreased in abundance relative to other common families at Ningaloo in the south, which might be related to persistence of more thermally and mechanically tolerant families. We identify regions where quantitative time-series data on coral cover and composition are lacking, particularly in north-western Australia. Standardising routine monitoring methods used by management and research agencies at these, and other locations, would allow a more robust assessment of coral condition and a better basis for conservation of coral reefs. PMID:23922829

  3. Coral Settlement on a Highly Disturbed Equatorial Reef System

    PubMed Central

    Bauman, Andrew G.; Guest, James R.; Dunshea, Glenn; Low, Jeffery; Todd, Peter A.; Steinberg, Peter D.

    2015-01-01

    Processes occurring early in the life stages of corals can greatly influence the demography of coral populations, and successful settlement of coral larvae that leads to recruitment is a critical life history stage for coral reef ecosystems. Although corals in Singapore persist in one the world’s most anthropogenically impacted reef systems, our understanding of the role of coral settlement in the persistence of coral communities in Singapore remains limited. Spatial and temporal patterns of coral settlement were examined at 7 sites in the southern islands of Singapore, using settlement tiles deployed and collected every 3 months from 2011 to 2013. Settlement occurred year round, but varied significantly across time and space. Annual coral settlement was low (~54.72 spat m-2 yr-1) relative to other equatorial regions, but there was evidence of temporal variation in settlement rates. Peak settlement occurred between March–May and September–November, coinciding with annual coral spawning periods (March–April and October), while the lowest settlement occurred from December–February during the northeast monsoon. A period of high settlement was also observed between June and August in the first year (2011/12), possibly due to some species spawning outside predicted spawning periods, larvae settling from other locations or extended larval settlement competency periods. Settlement rates varied significantly among sites, but spatial variation was relatively consistent between years, suggesting the strong effects of local coral assemblages or environmental conditions. Pocilloporidae were the most abundant coral spat (83.6%), while Poritidae comprised only 6% of the spat, and Acroporidae <1%. Other, unidentifiable families represented 10% of the coral spat. These results indicate that current settlement patterns are reinforcing the local adult assemblage structure (‘others’; i.e. sediment-tolerant coral taxa) in Singapore, but that the replenishment capacity of

  4. Coral settlement on a highly disturbed equatorial reef system.

    PubMed

    Bauman, Andrew G; Guest, James R; Dunshea, Glenn; Low, Jeffery; Todd, Peter A; Steinberg, Peter D

    2015-01-01

    Processes occurring early in the life stages of corals can greatly influence the demography of coral populations, and successful settlement of coral larvae that leads to recruitment is a critical life history stage for coral reef ecosystems. Although corals in Singapore persist in one the world's most anthropogenically impacted reef systems, our understanding of the role of coral settlement in the persistence of coral communities in Singapore remains limited. Spatial and temporal patterns of coral settlement were examined at 7 sites in the southern islands of Singapore, using settlement tiles deployed and collected every 3 months from 2011 to 2013. Settlement occurred year round, but varied significantly across time and space. Annual coral settlement was low (~54.72 spat m(-2) yr(-1)) relative to other equatorial regions, but there was evidence of temporal variation in settlement rates. Peak settlement occurred between March-May and September-November, coinciding with annual coral spawning periods (March-April and October), while the lowest settlement occurred from December-February during the northeast monsoon. A period of high settlement was also observed between June and August in the first year (2011/12), possibly due to some species spawning outside predicted spawning periods, larvae settling from other locations or extended larval settlement competency periods. Settlement rates varied significantly among sites, but spatial variation was relatively consistent between years, suggesting the strong effects of local coral assemblages or environmental conditions. Pocilloporidae were the most abundant coral spat (83.6%), while Poritidae comprised only 6% of the spat, and Acroporidae <1%. Other, unidentifiable families represented 10% of the coral spat. These results indicate that current settlement patterns are reinforcing the local adult assemblage structure ('others'; i.e. sediment-tolerant coral taxa) in Singapore, but that the replenishment capacity of Singapore

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

    EPA Science Inventory

    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...

  6. Recovery potential of the world's coral reef fishes.

    PubMed

    MacNeil, M Aaron; Graham, Nicholas A J; Cinner, Joshua E; Wilson, Shaun K; Williams, Ivor D; Maina, Joseph; Newman, Steven; Friedlander, Alan M; Jupiter, Stacy; Polunin, Nicholas V C; McClanahan, Tim R

    2015-04-16

    Continuing degradation of coral reef ecosystems has generated substantial interest in how management can support reef resilience. Fishing is the primary source of diminished reef function globally, leading to widespread calls for additional marine reserves to recover fish biomass and restore key ecosystem functions. Yet there are no established baselines for determining when these conservation objectives have been met or whether alternative management strategies provide similar ecosystem benefits. Here we establish empirical conservation benchmarks and fish biomass recovery timelines against which coral reefs can be assessed and managed by studying the recovery potential of more than 800 coral reefs along an exploitation gradient. We show that resident reef fish biomass in the absence of fishing (B0) averages ∼1,000 kg ha(-1), and that the vast majority (83%) of fished reefs are missing more than half their expected biomass, with severe consequences for key ecosystem functions such as predation. Given protection from fishing, reef fish biomass has the potential to recover within 35 years on average and less than 60 years when heavily depleted. Notably, alternative fisheries restrictions are largely (64%) successful at maintaining biomass above 50% of B0, sustaining key functions such as herbivory. Our results demonstrate that crucial ecosystem functions can be maintained through a range of fisheries restrictions, allowing coral reef managers to develop recovery plans that meet conservation and livelihood objectives in areas where marine reserves are not socially or politically feasible solutions.

  7. First frozen repository for the Great Barrier Reef coral created.

    PubMed

    Hagedorn, Mary; van Oppen, Madeleine J H; Carter, Virginia; Henley, Mike; Abrego, David; Puill-Stephan, Eneour; Negri, Andrew; Heyward, Andrew; MacFarlane, Doug; Spindler, Rebecca

    2012-10-01

    To build new tools for the continued protection and propagation of coral from the Great Barrier Reef (GBR), an international group of coral and cryopreservation scientists known as the Reef Recovery Initiative joined forces during the November 2011 mass-spawning event. The outcome was the creation of the first frozen bank for Australian coral from two important GBR reef-building species, Acropora tenuis and Acropora millepora. Approximately 190 frozen samples each with billions of cells were placed into long-term storage. Sperm cells were successfully cryopreserved, and after thawing, samples were used to fertilize eggs, resulting in functioning larvae. Additionally, developing larvae were dissociated, and these pluripotent cells were cryopreserved and viable after thawing. Now, we are in a unique position to move our work from the laboratory to the reefs to develop collaborative, practical conservation management tools to help secure Australia's coral biodiversity.

  8. Novel tradable instruments in the conservation of coral reefs, based on the coral gardening concept for reef restoration.

    PubMed

    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.

  9. Microbiota of the major South Atlantic reef building coral Mussismilia.

    PubMed

    Fernando, Samodha C; Wang, Jia; Sparling, Kimberly; Garcia, Gizele D; Francini-Filho, Ronaldo B; de Moura, Rodrigo L; Paranhos, Rodolfo; Thompson, Fabiano L; Thompson, Janelle R

    2015-02-01

    The Brazilian endemic scleractinian corals, genus Mussismilia, are among the main reef builders of the South Atlantic and are threatened by accelerating rates of disease. To better understand how holobiont microbial populations interact with corals during health and disease and to evaluate whether selective pressures in the holobiont or neutral assembly shape microbial composition, we have examined the microbiota structure of Mussismilia corals according to coral lineage, environment, and disease/health status. Microbiota of three Mussismilia species (Mussismilia harttii, Mussismilia hispida, and Mussismilia braziliensis) was compared using 16S rRNA pyrosequencing and clone library analysis of coral fragments. Analysis of biological triplicates per Mussismilia species and reef site allowed assessment of variability among Mussismilia species and between sites for M. braziliensis. From 173,487 V6 sequences, 6,733 coral- and 1,052 water-associated operational taxonomic units (OTUs) were observed. M. braziliensis microbiota was more similar across reefs than to other Mussismilia species microbiota from the same reef. Highly prevalent OTUs were more significantly structured by coral lineage and were enriched in Alpha- and Gammaproteobacteria. Bacterial OTUs from healthy corals were recovered from a M. braziliensis skeleton sample at twice the frequency of recovery from water or a diseased coral suggesting the skeleton is a significant habitat for microbial populations in the holobiont. Diseased corals were enriched with pathogens and opportunists (Vibrios, Bacteroidetes, Thalassomonas, and SRB). Our study examines for the first time intra- and inter-specific variability of microbiota across the genus Mussismilia. Changes in microbiota may be useful indicators of coral health and thus be a valuable tool for coral reef management and conservation.

  10. Reef ecology. Chemically mediated behavior of recruiting corals and fishes: a tipping point that may limit reef recovery.

    PubMed

    Dixson, Danielle L; Abrego, David; Hay, Mark E

    2014-08-22

    Coral reefs are in global decline, converting from dominance by coral to dominance by seaweed. Once seaweeds become abundant, coral recovery is suppressed unless herbivores return to remove seaweeds, and corals then recruit. Variance in the recovery of fishes and corals is not well understood. We show that juveniles of both corals and fishes are repelled by chemical cues from fished, seaweed-dominated reefs but attracted to cues from coral-dominated areas where fishing is prohibited. Chemical cues of specific seaweeds from degraded reefs repulsed recruits, and cues from specific corals that are typical of healthy reefs attracted recruits. Juveniles were present at but behaviorally avoided recruiting to degraded reefs dominated by seaweeds. For recovery, degraded reefs may need to be managed to produce cues that attract, rather than repel, recruiting corals and fishes.

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

    NASA Astrophysics Data System (ADS)

    Hochberg, E. J.

    2015-12-01

    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.

  12. Susceptibility of central Red Sea corals during a major bleaching event

    NASA Astrophysics Data System (ADS)

    Furby, K. A.; Bouwmeester, J.; Berumen, M. L.

    2013-06-01

    A major coral bleaching event occurred in the central Red Sea near Thuwal, Saudi Arabia, in the summer of 2010, when the region experienced up to 10-11 degree heating weeks. We documented the susceptibility of various coral taxa to bleaching at eight reefs during the peak of this thermal stress. Oculinids and agaricids were most susceptible to bleaching, with up to 100 and 80 % of colonies of these families, respectively, bleaching at some reefs. In contrast, some families, such as mussids, pocilloporids, and pectinids showed low levels of bleaching (<20 % on average). We resurveyed the reefs 7 months later to estimate subsequent mortality. Mortality was highly variable among taxa, with some taxa showing evidence of full recovery and some (e.g., acroporids) apparently suffering nearly complete mortality. The unequal mortality among families resulted in significant change in community composition following the bleaching. Significant factors in the likelihood of coral bleaching during this event were depth of the reef and distance of the reef from shore. Shallow reefs and inshore reefs had a higher prevalence of bleaching. This bleaching event shows that Red Sea reefs are subject to the same increasing pressures that reefs face worldwide. This study provides a quantitative, genus-level assessment of the vulnerability of various coral groups from within the Red Sea to bleaching and estimates subsequent mortality. As such, it can provide valuable insights into the future for reef communities in the Red Sea.

  13. Coral reef baselines: how much macroalgae is natural?

    PubMed

    Bruno, John F; Precht, William F; Vroom, Peter S; Aronson, Richard B

    2014-03-15

    Identifying the baseline or natural state of an ecosystem is a critical step in effective conservation and restoration. Like most marine ecosystems, coral reefs are being degraded by human activities: corals and fish have declined in abundance and seaweeds, or macroalgae, have become more prevalent. The challenge for resource managers is to reverse these trends, but by how much? Based on surveys of Caribbean reefs in the 1970s, some reef scientists believe that the average cover of seaweed was very low in the natural state: perhaps less than 3%. On the other hand, evidence from remote Pacific reefs, ecological theory, and impacts of over-harvesting in other systems all suggest that, historically, macroalgal biomass may have been higher than assumed. Uncertainties about the natural state of coral reefs illustrate the difficulty of determining the baseline condition of even well studied systems.

  14. Effects of solar ultraviolet radiation on coral reef organisms.

    PubMed

    Banaszak, Anastazia T; Lesser, Michael P

    2009-09-01

    Organisms living in shallow-water tropical coral reef environments are exposed to high UVR irradiances due to the low solar zenith angles (the angle of the sun from the vertical), the natural thinness of the ozone layer over tropical latitudes, and the high transparency of the water column. The hypothesis that solar ultraviolet radiation (UVR, 290-400 nm) is an important factor that affects the biology and ecology of coral reef organisms dates only to about 1980. It has been previously suggested that increased levels of biologically effective ultraviolet B radiation (UVB, 290-320 nm), which is the waveband primarily affected by ozone depletion, would have relatively small effects on corals and coral reefs and that these effects might be observed as changes in the minimum depths of occurrence of important reef taxa such as corals. This conclusion was based on predictions of increases in UVR as well as its attenuation with depth using the available data on UVR irradiances, ozone levels, and optical properties of the water overlying coral reefs. Here, we review the experimental evidence demonstrating the direct and indirect effects of UVR, both UVB and ultraviolet A (UVA, 320-400 nm) on corals and other reef associated biota, with emphasis on those studies conducted since 1996. Additionally, we re-examine the predictions made in 1996 for the increase in UVB on reefs with currently available data, assess whether those predictions were reasonable, and look at what changes might occur on coral reefs in the future as the multiple effects (i.e. increased temperature, hypercapnia, and ocean acidification) of global climate change continue.

  15. Can we measure beauty? Computational evaluation of coral reef aesthetics

    PubMed Central

    Guibert, Marine; Foerschner, Anja; Co, Tim; Calhoun, Sandi; George, Emma; Hatay, Mark; Dinsdale, Elizabeth; Sandin, Stuart A.; Smith, Jennifer E.; Vermeij, Mark J.A.; Felts, Ben; Dustan, Phillip; Salamon, Peter; Rohwer, Forest

    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, neglecting changes in their aesthetic appearance. Here we introduce a standardized computational approach to assess coral reef environments based on 109 visual features designed to evaluate the aesthetic appearance of art. The main feature groups include color intensity and diversity of the image, relative size, color, and distribution of discernable objects within the image, and texture. Specific coral reef aesthetic values combining all 109 features were calibrated against an established biogeochemical assessment (NCEAS) using machine learning algorithms. These values were generated for ∼2,100 random photographic images collected from 9 coral reef locations exposed to varying levels of anthropogenic influence across 2 ocean systems. Aesthetic values proved accurate predictors of the NCEAS scores (root mean square error < 5 for N ≥ 3) and significantly correlated to microbial abundance at each site. This shows that mathematical approaches designed to assess the aesthetic appearance of photographic images can be used as an inexpensive monitoring tool for coral reef ecosystems. It further suggests that human perception of aesthetics is not purely subjective but influenced by inherent reactions towards measurable visual cues. By quantifying aesthetic features of coral reef systems this method provides a cost efficient monitoring tool that targets one of the most important socioeconomic values of coral reefs directly tied to revenue for its local population. PMID:26587350

  16. Effects of cold stress and heat stress on coral fluorescence in reef-building corals

    PubMed Central

    Roth, Melissa S.; Deheyn, Dimitri D.

    2013-01-01

    Widespread temperature stress has caused catastrophic coral bleaching events that have been devastating for coral reefs. Here, we evaluate whether coral fluorescence could be utilized as a noninvasive assessment for coral health. We conducted cold and heat stress treatments on the branching coral Acropora yongei, and found that green fluorescent protein (GFP) concentration and fluorescence decreased with declining coral health, prior to initiation of bleaching. Ultimately, cold-treated corals acclimated and GFP concentration and fluorescence recovered. In contrast, heat-treated corals eventually bleached but showed strong fluorescence despite reduced GFP concentration, likely resulting from the large reduction in shading from decreased dinoflagellate density. Consequently, GFP concentration and fluorescence showed distinct correlations in non-bleached and bleached corals. Green fluorescence was positively correlated with dinoflagellate photobiology, but its closest correlation was with coral growth suggesting that green fluorescence could be used as a physiological proxy for health in some corals. PMID:23478289

  17. Effects of cold stress and heat stress on coral fluorescence in reef-building corals.

    PubMed

    Roth, Melissa S; Deheyn, Dimitri D

    2013-01-01

    Widespread temperature stress has caused catastrophic coral bleaching events that have been devastating for coral reefs. Here, we evaluate whether coral fluorescence could be utilized as a noninvasive assessment for coral health. We conducted cold and heat stress treatments on the branching coral Acropora yongei, and found that green fluorescent protein (GFP) concentration and fluorescence decreased with declining coral health, prior to initiation of bleaching. Ultimately, cold-treated corals acclimated and GFP concentration and fluorescence recovered. In contrast, heat-treated corals eventually bleached but showed strong fluorescence despite reduced GFP concentration, likely resulting from the large reduction in shading from decreased dinoflagellate density. Consequently, GFP concentration and fluorescence showed distinct correlations in non-bleached and bleached corals. Green fluorescence was positively correlated with dinoflagellate photobiology, but its closest correlation was with coral growth suggesting that green fluorescence could be used as a physiological proxy for health in some corals.

  18. 76 FR 66273 - Snapper-Grouper Fishery Off the Southern Atlantic States and Coral and Coral Reefs Fishery in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... Atlantic States and Coral and Coral Reefs Fishery in the South Atlantic; Exempted Fishing Permit AGENCY... Plan (FMP) for the Snapper-Grouper Fishery of the South Atlantic Region and the FMP for Coral,...

  19. The Microbial Signature Provides Insight into the Mechanistic Basis of Coral Success across Reef Habitats

    PubMed Central

    Leggat, William; Bongaerts, Pim

    2016-01-01

    ABSTRACT For ecosystems vulnerable to environmental change, understanding the spatiotemporal stability of functionally crucial symbioses is fundamental to determining the mechanisms by which these ecosystems may persist. The coral Pachyseris speciosa is a successful environmental generalist that succeeds in diverse reef habitats. The generalist nature of this coral suggests it may have the capacity to form functionally significant microbial partnerships to facilitate access to a range of nutritional sources within different habitats. Here, we propose that coral is a metaorganism hosting three functionally distinct microbial interactions: a ubiquitous core microbiome of very few symbiotic host-selected bacteria, a microbiome of spatially and/or regionally explicit core microbes filling functional niches (<100 phylotypes), and a highly variable bacterial community that is responsive to biotic and abiotic processes across spatial and temporal scales (>100,000 phylotypes). We find that this coral hosts upwards of 170,000 distinct phylotypes and provide evidence for the persistence of a select group of bacteria in corals across environmental habitats of the Great Barrier Reef and Coral Sea. We further show that a higher number of bacteria are consistently associated with corals on mesophotic reefs than on shallow reefs. An increase in microbial diversity with depth suggests reliance by this coral on bacteria for nutrient acquisition on reefs exposed to nutrient upwelling. Understanding the complex microbial communities of host organisms across broad biotic and abiotic environments as functionally distinct microbiomes can provide insight into those interactions that are ubiquitous niche symbioses and those that provide competitive advantage within the hosts’ environment. PMID:27460792

  20. Project Overview: A Reef Manager's Guide to Coral Bleaching ...

    EPA Pesticide Factsheets

    The purpose of this report is to provide the latest scientific knowledge and discuss available management options to assist local and regional managers in responding effectively to mass coral bleaching events. Background A Reef Manager’s Guide to Coral Bleaching is the result of a collaborative effort by over 50 scientists and managers to: (1) share the best available scientific information on climate-related coral bleaching; and (2) compile a tool kit of currently available strategies for adaptive management of coral reefs in a changing climate. The result is a compendium of current information, tools, and practical suggestions to aid managers in their efforts to protect reefs in a way that maximizes reef resilience in the face of continuing climate change. The Guide is a joint publication of the National Oceanic and Atmospheric Administration, the Great Barrier Reef Marine Park Authority, and The World Conservation Union, with author contributions from a variety of international partners from government agencies, non-governmental organizations, and academic institutions. EPA’s Office of Research and Development was a major contributor to the Guide through authorship and participation in the final review and editing process for the entire report. A Reef Manager’s Guide to Coral Bleaching is the result of a collaborative effort by over 50 scientists and managers to: (1) share the best available scientific information on climate-related coral blea

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

    PubMed

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

    2017-04-04

    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.

  2. Reefs of the deep: the biology and geology of cold-water coral ecosystems.

    PubMed

    Roberts, J Murray; Wheeler, Andrew J; Freiwald, André

    2006-04-28

    Coral reefs are generally associated with shallow tropical seas; however, recent deep-ocean exploration using advanced acoustics and submersibles has revealed unexpectedly widespread and diverse coral ecosystems in deep waters on continental shelves, slopes, seamounts, and ridge systems around the world. Advances reviewed here include the use of corals as paleoclimatic archives and their biogeological functioning, biodiversity, and biogeography. Threats to these fragile, long-lived, and rich ecosystems are mounting: The impacts of deep-water trawling are already widespread, and effects of ocean acidification are potentially devastating.

  3. Tropical dead zones and mass mortalities on coral reefs.

    PubMed

    Altieri, Andrew H; Harrison, Seamus B; Seemann, Janina; Collin, Rachel; Diaz, Robert J; Knowlton, Nancy

    2017-04-04

    Degradation of coastal water quality in the form of low dissolved oxygen levels (hypoxia) can harm biodiversity, ecosystem function, and human wellbeing. Extreme hypoxic conditions along the coast, leading to what are often referred to as "dead zones," are known primarily from temperate regions. However, little is known about the potential threat of hypoxia in the tropics, even though the known risk factors, including eutrophication and elevated temperatures, are common. Here we document an unprecedented hypoxic event on the Caribbean coast of Panama and assess the risk of dead zones to coral reefs worldwide. The event caused coral bleaching and massive mortality of corals and other reef-associated organisms, but observed shifts in community structure combined with laboratory experiments revealed that not all coral species are equally sensitive to hypoxia. Analyses of global databases showed that coral reefs are associated with more than half of the known tropical dead zones worldwide, with >10% of all coral reefs at elevated risk for hypoxia based on local and global risk factors. Hypoxic events in the tropics and associated mortality events have likely been underreported, perhaps by an order of magnitude, because of the lack of local scientific capacity for their detection. Monitoring and management plans for coral reef resilience should incorporate the growing threat of coastal hypoxia and include support for increased detection and research capacity.

  4. Coral Reefs on the Edge? Carbon Chemistry on Inshore Reefs of the Great Barrier Reef

    PubMed Central

    Uthicke, Sven; Furnas, Miles; Lønborg, Christian

    2014-01-01

    While increasing atmospheric carbon dioxide (CO2) concentration alters global water chemistry (Ocean Acidification; OA), the degree of changes vary on local and regional spatial scales. Inshore fringing coral reefs of the Great Barrier Reef (GBR) are subjected to a variety of local pressures, and some sites may already be marginal habitats for corals. The spatial and temporal variation in directly measured parameters: Total Alkalinity (TA) and dissolved inorganic carbon (DIC) concentration, and derived parameters: partial pressure of CO2 (pCO2); pH and aragonite saturation state (Ωar) were measured at 14 inshore reefs over a two year period in the GBR region. Total Alkalinity varied between 2069 and 2364 µmol kg−1 and DIC concentrations ranged from 1846 to 2099 µmol kg−1. This resulted in pCO2 concentrations from 340 to 554 µatm, with higher values during the wet seasons and pCO2 on inshore reefs distinctly above atmospheric values. However, due to temperature effects, Ωar was not further reduced in the wet season. Aragonite saturation on inshore reefs was consistently lower and pCO2 higher than on GBR reefs further offshore. Thermodynamic effects contribute to this, and anthropogenic runoff may also contribute by altering productivity (P), respiration (R) and P/R ratios. Compared to surveys 18 and 30 years ago, pCO2 on GBR mid- and outer-shelf reefs has risen at the same rate as atmospheric values (∼1.7 µatm yr−1) over 30 years. By contrast, values on inshore reefs have increased at 2.5 to 3 times higher rates. Thus, pCO2 levels on inshore reefs have disproportionately increased compared to atmospheric levels. Our study suggests that inshore GBR reefs are more vulnerable to OA and have less buffering capacity compared to offshore reefs. This may be caused by anthropogenically induced trophic changes in the water column and benthos of inshore reefs subjected to land runoff. PMID:25295864

  5. Coral reefs on the edge? Carbon chemistry on inshore reefs of the great barrier reef.

    PubMed

    Uthicke, Sven; Furnas, Miles; Lønborg, Christian

    2014-01-01

    While increasing atmospheric carbon dioxide (CO2) concentration alters global water chemistry (Ocean Acidification; OA), the degree of changes vary on local and regional spatial scales. Inshore fringing coral reefs of the Great Barrier Reef (GBR) are subjected to a variety of local pressures, and some sites may already be marginal habitats for corals. The spatial and temporal variation in directly measured parameters: Total Alkalinity (TA) and dissolved inorganic carbon (DIC) concentration, and derived parameters: partial pressure of CO2 (pCO2); pH and aragonite saturation state (Ωar) were measured at 14 inshore reefs over a two year period in the GBR region. Total Alkalinity varied between 2069 and 2364 µmol kg-1 and DIC concentrations ranged from 1846 to 2099 µmol kg-1. This resulted in pCO2 concentrations from 340 to 554 µatm, with higher values during the wet seasons and pCO2 on inshore reefs distinctly above atmospheric values. However, due to temperature effects, Ωar was not further reduced in the wet season. Aragonite saturation on inshore reefs was consistently lower and pCO2 higher than on GBR reefs further offshore. Thermodynamic effects contribute to this, and anthropogenic runoff may also contribute by altering productivity (P), respiration (R) and P/R ratios. Compared to surveys 18 and 30 years ago, pCO2 on GBR mid- and outer-shelf reefs has risen at the same rate as atmospheric values (∼1.7 µatm yr-1) over 30 years. By contrast, values on inshore reefs have increased at 2.5 to 3 times higher rates. Thus, pCO2 levels on inshore reefs have disproportionately increased compared to atmospheric levels. Our study suggests that inshore GBR reefs are more vulnerable to OA and have less buffering capacity compared to offshore reefs. This may be caused by anthropogenically induced trophic changes in the water column and benthos of inshore reefs subjected to land runoff.

  6. Local Stressors, Resilience, and Shifting Baselines on Coral Reefs

    PubMed Central

    McLean, Matthew; Cuetos-Bueno, Javier; Nedlic, Osamu; Luckymiss, Marston; Houk, Peter

    2016-01-01

    Understanding how and why coral reefs have changed over the last twenty to thirty years is crucial for sustaining coral-reef resilience. We used a historical baseline from Kosrae, a typical small island in Micronesia, to examine changes in fish and coral assemblages since 1986. We found that natural gradients in the spatial distribution of fish and coral assemblages have become amplified, as island geography is now a stronger determinant of species abundance patterns, and habitat forming Acropora corals and large-bodied fishes that were once common on the leeward side of the island have become scarce. A proxy for fishing access best predicted the relative change in fish assemblage condition over time, and in turn, declining fish condition was the only factor correlated with declining coral condition, suggesting overfishing may have reduced ecosystem resilience. Additionally, a proxy for watershed pollution predicted modern coral assemblage condition, suggesting pollution is also reducing resilience in densely populated areas. Altogether, it appears that unsustainable fishing reduced ecosystem resilience, as fish composition has shifted to smaller species in lower trophic levels, driven by losses of large predators and herbivores. While prior literature and anecdotal reports indicate that major disturbance events have been rare in Kosrae, small localized disturbances coupled with reduced resilience may have slowly degraded reef condition through time. Improving coral-reef resilience in the face of climate change will therefore require improved understanding and management of growing artisanal fishing pressure and watershed pollution. PMID:27902715

  7. Local Stressors, Resilience, and Shifting Baselines on Coral Reefs.

    PubMed

    McLean, Matthew; Cuetos-Bueno, Javier; Nedlic, Osamu; Luckymiss, Marston; Houk, Peter

    2016-01-01

    Understanding how and why coral reefs have changed over the last twenty to thirty years is crucial for sustaining coral-reef resilience. We used a historical baseline from Kosrae, a typical small island in Micronesia, to examine changes in fish and coral assemblages since 1986. We found that natural gradients in the spatial distribution of fish and coral assemblages have become amplified, as island geography is now a stronger determinant of species abundance patterns, and habitat forming Acropora corals and large-bodied fishes that were once common on the leeward side of the island have become scarce. A proxy for fishing access best predicted the relative change in fish assemblage condition over time, and in turn, declining fish condition was the only factor correlated with declining coral condition, suggesting overfishing may have reduced ecosystem resilience. Additionally, a proxy for watershed pollution predicted modern coral assemblage condition, suggesting pollution is also reducing resilience in densely populated areas. Altogether, it appears that unsustainable fishing reduced ecosystem resilience, as fish composition has shifted to smaller species in lower trophic levels, driven by losses of large predators and herbivores. While prior literature and anecdotal reports indicate that major disturbance events have been rare in Kosrae, small localized disturbances coupled with reduced resilience may have slowly degraded reef condition through time. Improving coral-reef resilience in the face of climate change will therefore require improved understanding and management of growing artisanal fishing pressure and watershed pollution.

  8. EFFECTS OF GLOBAL CHANGE ON CORAL REEF ECOSYSTEMS

    EPA Science Inventory

    Corals and coral reefs of the Caribbean and through the world are deteriorating at an accelerated rate. Several stressors are believed to contrbute to this decline, including global changes in atmospheric gases and land use patterns. In particular, warmer water temperatures and...

  9. Temperature Regimes Impact Coral Assemblages along Environmental Gradients on Lagoonal Reefs in Belize

    PubMed Central

    Townsend, Joseph E.; Courtney, Travis A.; Aichelman, Hannah E.; Davies, Sarah W.; Lima, Fernando P.; Castillo, Karl D.

    2016-01-01

    Coral reefs are increasingly threatened by global and local anthropogenic stressors such as rising seawater temperature, nutrient enrichment, sedimentation, and overfishing. Although many studies have investigated the impacts of local and global stressors on coral reefs, we still do not fully understand how these stressors influence coral community structure, particularly across environmental gradients on a reef system. Here, we investigate coral community composition across three different temperature and productivity regimes along a nearshore-offshore gradient on lagoonal reefs of the Belize Mesoamerican Barrier Reef System (MBRS). A novel metric was developed using ultra-high-resolution satellite-derived estimates of sea surface temperatures (SST) to classify reefs as exposed to low (lowTP), moderate (modTP), or high (highTP) temperature parameters over 10 years (2003 to 2012). Coral species richness, abundance, diversity, density, and percent cover were lower at highTP sites relative to lowTP and modTP sites, but these coral community traits did not differ significantly between lowTP and modTP sites. Analysis of coral life history strategies revealed that highTP sites were dominated by hardy stress-tolerant and fast-growing weedy coral species, while lowTP and modTP sites consisted of competitive, generalist, weedy, and stress-tolerant coral species. Satellite-derived estimates of Chlorophyll-a (chl-a) were obtained for 13-years (2003–2015) as a proxy for primary production. Chl-a concentrations were highest at highTP sites, medial at modTP sites, and lowest at lowTP sites. Notably, thermal parameters correlated better with coral community traits between site types than productivity, suggesting that temperature (specifically number of days above the thermal bleaching threshold) played a greater role in defining coral community structure than productivity on the MBRS. Dominance of weedy and stress-tolerant genera at highTP sites suggests that corals utilizing

  10. Temperature Regimes Impact Coral Assemblages along Environmental Gradients on Lagoonal Reefs in Belize.

    PubMed

    Baumann, Justin H; Townsend, Joseph E; Courtney, Travis A; Aichelman, Hannah E; Davies, Sarah W; Lima, Fernando P; Castillo, Karl D

    2016-01-01

    Coral reefs are increasingly threatened by global and local anthropogenic stressors such as rising seawater temperature, nutrient enrichment, sedimentation, and overfishing. Although many studies have investigated the impacts of local and global stressors on coral reefs, we still do not fully understand how these stressors influence coral community structure, particularly across environmental gradients on a reef system. Here, we investigate coral community composition across three different temperature and productivity regimes along a nearshore-offshore gradient on lagoonal reefs of the Belize Mesoamerican Barrier Reef System (MBRS). A novel metric was developed using ultra-high-resolution satellite-derived estimates of sea surface temperatures (SST) to classify reefs as exposed to low (lowTP), moderate (modTP), or high (highTP) temperature parameters over 10 years (2003 to 2012). Coral species richness, abundance, diversity, density, and percent cover were lower at highTP sites relative to lowTP and modTP sites, but these coral community traits did not differ significantly between lowTP and modTP sites. Analysis of coral life history strategies revealed that highTP sites were dominated by hardy stress-tolerant and fast-growing weedy coral species, while lowTP and modTP sites consisted of competitive, generalist, weedy, and stress-tolerant coral species. Satellite-derived estimates of Chlorophyll-a (chl-a) were obtained for 13-years (2003-2015) as a proxy for primary production. Chl-a concentrations were highest at highTP sites, medial at modTP sites, and lowest at lowTP sites. Notably, thermal parameters correlated better with coral community traits between site types than productivity, suggesting that temperature (specifically number of days above the thermal bleaching threshold) played a greater role in defining coral community structure than productivity on the MBRS. Dominance of weedy and stress-tolerant genera at highTP sites suggests that corals utilizing

  11. Responses of algae, corals and fish to the reduction of macroalgae in fished and unfished patch reefs of Glovers Reef Atoll, Belize

    NASA Astrophysics Data System (ADS)

    McClanahan, T.; McField, M.; Huitric, M.; Bergman, K.; Sala, E.; Nyström, M.; Nordemar, I.; Elfwing, T.; Muthiga, N.

    2001-05-01

    Macroalgae were experimentally reduced by approximately 2.5 kg/m2 on eight similar-sized patch reefs of Glovers Reef Atoll, Belize, in September 1998. Four of these reefs were in a protected "no-take" zone and four were in a "general use" fishing zone. Eight adjacent reefs (four in each management zone) were also studied as unmanipulated controls to determine the interactive effect of algal reduction and fisheries management on algae, coral, fish, and rates of herbivory. The 16 reefs were sampled five times for 1 year after the manipulation. We found that the no-fishing zone had greater population densities for 13 of 30 species of fish, including four herbivorous species, but lower herbivory levels by sea urchins. However, there was lower stony coral cover and higher macroalgal cover in the "no-take" zone, both prior to and after the experiment. There were no significant effects of management on the percent cover of fleshy macroalgae. The algal reduction resulted in an increase in six fish species, including four herbivores and two which feed on invertebrates. One species, Lutjanus griseus, declined in experimental reefs. Macroalgal biomass quickly recovered from the reduction in both management areas within a few months, and by species-level community measures within 1 year, while stony coral was reduced in all treatments. Coral bleaching and Hurricane Mitch disturbed the site at the beginning of the study period and may explain the loss of stony coral and rapid increase in erect algae. We suggest that reducing macroalgae, as a technique to restore turf and encrusting coralline algae and stony corals, may work best after reefs have been fully protected from fishing for a period long enough to allow herbivorous fish to recover (i.e. >5 years). Further ecological studies on Glovers Reef are required to understand the shift from coral to algal dominance that has occurred on this reef in the last 25 years.

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

    USGS Publications Warehouse

    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

  13. Holocene aggradation of the Dry Tortugas coral reef ecosystem

    USGS Publications Warehouse

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

    2010-01-01

    Radiometric age dating of reef cores acquired at the Dry Tortugas coral reef ecosystem (DTCRE) was merged with lidar topographic mapping to examine Holocene reef development linked to spatial variation in growth and erosion under the control of sea level. Analysis of variance of lidar topography confirmed the presence of three distinct terraces on all three major DTCRE banks (Loggerhead Bank, Garden Bank, and Pulaski Bank). Reef building on the middle terrace (T2) began atop Pleistocene edifices on Loggerhead Bank by 8.0 ka (thousands of years ago) and on Garden Bank by 7.2 ka at elevations of about −16.0 m and −11.9 m, respectively, relative to present mean sea level. Following this initiation at different elevations, T2 aggraded vertically on both banks at different rates during the early Holocene under foundering conditions until a highstand at 5.2 ka, resulting in a 2.21 m offset in present mean T2 elevation between these banks. Initiation of an upper terrace (T1) occurred on both Loggerhead Bank and Garden Bank in association with sea-level fall to a lowstand at near 4.8 ka. This upper terrace initiated on Garden Bank at about 5.0 ka and then grew upward at rate of 2.5 mm year−1 until approximately 3.8 ka. On Loggerhead Bank, the upper T1 terrace formed after 4.5 ka at a higher vertical aggradation rate of 4.1 mm year−1, but at a lower elevation than on Garden Bank. Terrace T1 aggraded on Loggerhead Bank below the elevation of lowstands during late Holocene sea-level oscillation, and consequently erosion on Loggerhead Bank was minimal and likely limited to the crest of the upper terrace. In contrast, after 3.8 ka terrace T1 on Garden Bank likely tracked sea level and consequently underwent erosion when sea level fell to second, third and fourth lowstands at 3.3, 1.1, and 0.3 ka.

  14. Nutrient Enrichment Coupled with Sedimentation Favors Sea Anemones over Corals

    PubMed Central

    Liu, Pi-Jen; Hsin, Min-Chieh; Huang, Yen-Hsun; Fan, Tung-Yung; Meng, Pei-Jie; Lu, Chung-Cheng; Lin, Hsing-Juh

    2015-01-01

    Fine sediments, which account for the majority of total fluvial sediment flux, have been suggested to degrade coral reefs on a global scale. Furthermore, sediment impacts can be exacerbated by extreme rainfall events associated with global climate change and anthropogenic nutrient enrichment. We report the findings from a series of mesocosm experiments exploring the effects of short-term sedimentation and nutrient enrichment on the interactions between the hard coral Acropora muricata, the sea anemone Mesactinia ganesis, and the green macroalga Codium edule. Mesocosms were manipulated to simulate either unimpacted reefs or reefs exposed to elevated levels of fine sediments for 10 or 14 days to simulate the effects of heavy rainfall. The first and second experiments were aimed to examine the effects of inorganic and organic sediments, respectively. The third experiment was designed to examine the interactive effects of nutrient enrichment and elevated sediment loads. Neither inorganic nor organic sediment loadings significantly affected the physiological performance of the coral, but, importantly, did reduce its ability to compete with other organisms. Photosynthetic efficiencies of both the green macroalga and the sea anemone increased in response to both sediment loadings when they were simultaneously exposed to nutrient enrichment. While organic sediment loading increased the nitrogen content of the green macroalga in the first experiment, inorganic sediment loading increased its phosphorus content in the second experiment. The coral mortality due to sea anemones attack was significantly greater upon exposure to enriched levels of organic sediments and nutrients. Our findings suggest that the combined effects of short-term sedimentation and nutrient enrichment could cause replacement of corals by sea anemones on certain coral reefs. PMID:25897844

  15. Hydrodynamic Regimes Affect Coral Reef Resilience to Ocean Acidification

    NASA Astrophysics Data System (ADS)

    Teneva, L. T.; Dunbar, R. B.; Koseff, J. R.; Fleischfresser, J. D.; Koweek, D.

    2013-05-01

    Caribbean reefs hold tremendous value as sources of food, income, coastal protection, in addition to their cultural significance. Recently, studies showed that Caribbean reef growth has been surpassed in places by excessive rates of erosion due to climate change. The rates of coral reef response to ocean pH changes and warming and the implications for ecosystem resilience remain largely unknown. One way to investigate the potential structural resilience of reefs to climate change is to measure the physical oceanographic conditions in the area. Determining the hydrodynamic regimes and residence time of water in a particular reef environment is crucial to understanding the rates of future warming and acidification a reef site would experience. Our work on Pacific Islands' hydrodynamics - Central Equatorial Pacific, Great Barrier Reef, and Western Pacific -- would be of interest to Caribbean physical oceanographers and coral reef scientists. We use a combination of Acoustic Doppler Current Profilers, Acoustic Doppler Velocimeters, temperature and salinity sensors, and pressure sensors to characterize reef hydrodynamic regimes. Our work indicates that shallower, more protected reef habitats are characterized by longer residence times, their biological signals are strongly tidally modulated, essentially subjecting such habitats to higher rates of warming and acidification in the future. Reef crest environments and fore reef habitats, on the other hand, are well-mixed with open-ocean water. The hydrodynamic regimes there condition such reef sites to more attenuated temperature and pH ranges, conditions more typical of the open ocean. Our work suggests that investigating the geomorphology and resulting localized hydrodynamics in a reef area can provide insights into the relative rates at which a reef could resist or succumb to impacts of ocean acidification. Such information for different reef islands, in the Pacific or Caribbean basins, could provide helpful insights

  16. Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan).

    PubMed

    Hassona, Rifaat K; Sam, A K; Osman, O I; Sirelkhatim, D A; LaRosa, J

    2008-04-15

    An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing (210)Po and (137)Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of (210)Po were found in the ranges 0.25-6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of (210)Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (microSv/yr) in carnivores, omnivores and herbivores, respectively, for (137)Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For (210)Po, it was found to be 3.47, 4.81 and 4.14 (microSv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of (137)Cs is negligible compared to (210)Po.

  17. Challenges for Ecosystem Services Provided by Coral Reefs In the Face of Climate Change

    NASA Astrophysics Data System (ADS)

    Kikuchi, R. K.; Elliff, C. I.

    2014-12-01

    Coral reefs provide many ecosystem services of which coastal populations are especially dependent upon, both in cases of extreme events and in daily life. However, adaptation to climate change is still relatively unknown territory regarding the ecosystem services provided by coastal environments, such as coral reefs. Management strategies usually consider climate change as a distant issue and rarely include ecosystem services in decision-making. Coral reefs are among the most vulnerable environments to climate change, considering the impact that increased ocean temperature and acidity have on the organisms that compose this ecosystem. If no actions are taken, the most likely scenario to occur will be of extreme decline in the ecosystem services provided by coral reefs. Loss of biodiversity due to the pressures of ocean warming and acidification will lead to increased price of seafood products, negative impact on food security, and ecological imbalances. Also, sea-level rise and fragile structures due to carbonate dissolution will increase vulnerability to storms, which can lead to shoreline erosion and ultimately threaten coastal communities. Both these conditions will undoubtedly affect recreation and tourism, which are often the most important use values in the case of coral reef systems. Adaptation strategies to climate change must take on an ecosystem-based approach with continuous monitoring programs, so that multiple ecosystem services are considered and not only retrospective trends are analyzed. Brazilian coral reefs have been monitored on a regular basis since 2000 and, considering that these marginal coral reefs of the eastern Atlantic are naturally under stressful conditions (e.g. high sedimentation rates), inshore reefs of Brazil, such as those in Tinharé-Boipeba, have shown lower vitality rates due to greater impacts from the proximity to the coastal area (e.g. pollution, overfishing, sediment run-off). This chronic negative impact must be addressed

  18. U.S. coral reefs; imperiled national treasures

    USGS Publications Warehouse

    Field, M.E.; Cochran, S.A.; Evans, K.R.

    2002-01-01

    Coral reefs are home to 25% of all marine species. However, the tiny colonial animals that build these intricate limestone masses are dying at alarming rates. If this trend continues, in 20 years the living corals on many of the world's reefs will be dead and the ecosystems that depend on them severely damaged. As part of the effort to protect our Nation's extensive reefs, U.S. Geological Survey (USGS) scientists are working to better understand the processes that affect the health of these ecologically and economically important ecosystems.

  19. Coral reproduction in the world's warmest reefs: southern Persian Gulf (Dubai, United Arab Emirates)

    NASA Astrophysics Data System (ADS)

    Bauman, A. G.; Baird, A. H.; Cavalcante, G. H.

    2011-06-01

    Despite extensive research on coral reproduction from numerous geographic locations, there remains limited knowledge within the Persian Gulf. Given that corals in the Persian Gulf exist in one of the most stressful environments for reef corals, with annual variations in sea surface temperature (SST) of 12°C and maximum summer mean SSTs of 36°C, understanding coral reproductive biology in the Gulf may provide clues as to how corals may cope with global warming. In this study, we examined six locally common coral species on two shallow reef sites in Dubai, United Arab Emirates (UAE), in 2008 and 2009 to investigate the patterns of reproduction, in particular the timing and synchrony of spawning. In total, 71% colonies in April 2008 and 63% colonies in April 2009 contained mature oocytes. However, the presence of mature gametes in May indicated that spawning was potentially split between April and May in all species. These results demonstrate that coral reproduction patterns within this region are highly seasonal and that multi-species spawning synchrony is highly probable. Acropora downingi, Cyphastrea microphthalma and Platygyra daedalea were all hermaphroditic broadcast spawners with a single annual gametogenic cycle. Furthermore, fecundity and mature oocyte sizes were comparable to those in other regions. We conclude that the reproductive biology of corals in the southern Persian Gulf is similar to other regions, indicating that these species have adapted to the extreme environmental conditions in the southern Persian Gulf.

  20. Multi-scale remote sensing of coral reefs

    USGS Publications Warehouse

    Andréfouët, Serge; Hochberg, E.J.; Chevillon, Christophe; Muller-Karger, Frank E.; Brock, John C.; Hu, Chuanmin

    2005-01-01

    In this chapter we present how both direct and indirect remote sensing can be integrated to address two major coral reef applications - coral bleaching and assessment of biodiversity. This approach reflects the current non-linear integration of remote sensing for environmental assessment of coral reefs, resulting from a rapid increase in available sensors, processing methods and interdisciplinary collaborations (Andréfouët and Riegl, 2004). Moreover, this approach has greatly benefited from recent collaborations of once independent investigations (e.g., benthic ecology, remote sensing, and numerical modeling).

  1. St. Petersburg Coastal and Marine Science Center coral reef research

    USGS Publications Warehouse

    Poore, Richard Z.; Kuffner, Ilsa B.; Kellogg, Christina A.

    2010-01-01

    The U.S. Geological Survey (USGS) Coral Reef Ecosystem STudies (CREST) Project specifically addresses priorities identified in the 'Facing tomorrow's challenges' U.S. Geological Survey science in the decade 2007-2017' document (USGS, 2007). Research includes a blend of historical, monitoring, and process studies aimed at improving our understanding of the development, current status and function, as well as likely future changes in coral ecosystems. Topics such as habitat characterization and distribution, coral disease, and trends in biogenic calcification are major focus areas. We seek to increase the understanding of reef structure, ecological integrity, and responses to global change.

  2. Coastal Benthic Optical Properties (CoBOP) of Coral Reef Environments: Small Scale Fluorescent Optical Signatures and Hyperspectral Remote Sensing of Coral Reef Habitats

    DTIC Science & Technology

    2001-09-30

    Coastal Benthic Optical Properties (CoBOP) of Coral Reef Environments: Small Scale Fluorescent Optic