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.

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

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.

Reef flattening effects on total richness and species responses in the Caribbean.

PubMed

Newman, Steven P; Meesters, Erik H; Dryden, Charlie S; Williams, Stacey M; Sanchez, Cristina; Mumby, Peter J; Polunin, Nicholas V C

2015-11-01

There has been ongoing flattening of Caribbean coral reefs with the loss of habitat having severe implications for these systems. Complexity and its structural components are important to fish species richness and community composition, but little is known about its role for other taxa or species-specific responses. This study reveals the importance of reef habitat complexity and structural components to different taxa of macrofauna, total species richness, and individual coral and fish species in the Caribbean. Species presence and richness of different taxa were visually quantified in one hundred 25-m(2) plots in three marine reserves in the Caribbean. Sampling was evenly distributed across five levels of visually estimated reef complexity, with five structural components also recorded: the number of corals, number of large corals, slope angle, maximum sponge and maximum octocoral height. Taking advantage of natural heterogeneity in structural complexity within a particular coral reef habitat (Orbicella reefs) and discrete environmental envelope, thus minimizing other sources of variability, the relative importance of reef complexity and structural components was quantified for different taxa and individual fish and coral species on Caribbean coral reefs using boosted regression trees (BRTs). Boosted regression tree models performed very well when explaining variability in total (82·3%), coral (80·6%) and fish species richness (77·3%), for which the greatest declines in richness occurred below intermediate reef complexity levels. Complexity accounted for very little of the variability in octocorals, sponges, arthropods, annelids or anemones. BRTs revealed species-specific variability and importance for reef complexity and structural components. Coral and fish species occupancy generally declined at low complexity levels, with the exception of two coral species (Pseudodiploria strigosa and Porites divaricata) and four fish species (Halichoeres bivittatus, H. maculipinna, Malacoctenus triangulatus and Stegastes partitus) more common at lower reef complexity levels. A significant interaction between country and reef complexity revealed a non-additive decline in species richness in areas of low complexity and the reserve in Puerto Rico. Flattening of Caribbean coral reefs will result in substantial species losses, with few winners. Individual structural components have considerable value to different species, and their loss may have profound impacts on population responses of coral and fish due to identity effects of key species, which underpin population richness and resilience and may affect essential ecosystem processes and services. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Integrating structure-from-motion photogrammetry with geospatial software as a novel technique for quantifying 3D ecological characteristics of coral reefs

PubMed Central

Delparte, D; Gates, RD; Takabayashi, M

2015-01-01

The structural complexity of coral reefs plays a major role in the biodiversity, productivity, and overall functionality of reef ecosystems. Conventional metrics with 2-dimensional properties are inadequate for characterization of reef structural complexity. A 3-dimensional (3D) approach can better quantify topography, rugosity and other structural characteristics that play an important role in the ecology of coral reef communities. Structure-from-Motion (SfM) is an emerging low-cost photogrammetric method for high-resolution 3D topographic reconstruction. This study utilized SfM 3D reconstruction software tools to create textured mesh models of a reef at French Frigate Shoals, an atoll in the Northwestern Hawaiian Islands. The reconstructed orthophoto and digital elevation model were then integrated with geospatial software in order to quantify metrics pertaining to 3D complexity. The resulting data provided high-resolution physical properties of coral colonies that were then combined with live cover to accurately characterize the reef as a living structure. The 3D reconstruction of reef structure and complexity can be integrated with other physiological and ecological parameters in future research to develop reliable ecosystem models and improve capacity to monitor changes in the health and function of coral reef ecosystems. PMID:26207190

Measuring, interpreting, and responding to changes in coral reefs: A challenge for biologists, geologist, and managers

USGS Publications Warehouse

Rogers, Caroline S.; Miller, Jeff; Hubbard, Dennis K.; Rogers, Caroline S.; Lipps, Jere H.; Stanley, George D.

2016-01-01

What, exactly, is a coral reef? And how have the world’s reefs changed in the last several decades? What are the stressors undermining reef structure and function? Given the predicted effects of climate change, do reefs have a future? Is it possible to “manage” coral reefs for resilience? What can coral reef scientists contribute to improve protection and management of coral reefs? What insights can biologists and geologists provide regarding the persistence of coral reefs on a human timescale? What is reef change to a biologist… to a geologist?Clearly, there are many challenging questions. In this chapter, we present some of our thoughts on monitoring and management of coral reefs in US national parks in the Caribbean and western Atlantic based on our experience as members of monitoring teams. We reflect on the need to characterize and evaluate reefs, on how to conduct high-quality monitoring programs, and on what we can learn from biological and geological experiments and investigations. We explore the possibility that specific steps can be taken to “manage” coral reefs for greater resilience.

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

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

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

PubMed

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

2016-11-08

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

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

PubMed Central

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

2016-01-01

Coral cover on reefs is declining globally due to coastal development, overfishing and climate change. Reefs isolated from direct human influence can recover from natural acute disturbances, but little is known about long term recovery of reefs experiencing chronic human disturbances. Here we investigate responses to acute bleaching disturbances on turbid reefs off Singapore, at two depths over a period of 27 years. Coral cover declined and there were marked changes in coral and benthic community structure during the first decade of monitoring at both depths. At shallower reef crest sites (3–4 m), benthic community structure recovered towards pre-disturbance states within a decade. In contrast, there was a net decline in coral cover and continuing shifts in community structure at deeper reef slope sites (6–7 m). There was no evidence of phase shifts to macroalgal dominance but coral habitats at deeper sites were replaced by unstable substrata such as fine sediments and rubble. The persistence of coral dominance at chronically disturbed shallow sites is likely due to an abundance of coral taxa which are tolerant to environmental stress. In addition, high turbidity may interact antagonistically with other disturbances to reduce the impact of thermal stress and limit macroalgal growth rates. PMID:27824083

Community Structure Of Coral Reefs In Saebus Island, Sumenep District, East Java

NASA Astrophysics Data System (ADS)

Rizmaadi, Mada; Riter, Johannes; Fatimah, Siti; Rifaldi, Riyan; Yoga, Arditho; Ramadhan, Fikri; Ambariyanto, Ambariyanto

2018-02-01

Increasing degradation coral reefs ecosystem has created many concerns. Reduction of this damage can only be done with good and proper management of coral reef ecosystem based on existing condition. The condition of coral reef ecosystem can be determined by assessing its community structure. This study investigates community structure of coral reef ecosystems around Saebus Island, Sumenep District, East Java, by using satellite imagery analysis and field observations. Satellite imagery analysis by Lyzenga methods was used to determine the observation stations and substrate distribution. Field observations were done by using Line Intercept Transect method at 4 stations, at the depth of 3 and 10 meters. The results showed that the percentage of coral reef coverage at the depth of 3 and 10 meters were 64.36% and 59.29%, respectively, and included in fine coverage category. This study found in total 25 genera from 13 families of corals at all stations. The most common species found were Acropora, Porites, and Pocillopora, while the least common species were Favites and Montastrea. Average value of Diversity, Uniformity and Dominancy indices were 2.94, 0.8 and 0.18 which include as medium, high, and low category, respectively. These results suggest that coral reef ecosystems around Saebus Island is in a good condition.

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

PubMed

Lirman, Diego; Fong, Peggy

2007-06-01

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

Workshop on Biological Integrity of Coral Reefs August 21-22 ...

EPA Pesticide Factsheets

This report summarizes an EPA-sponsored workshop on coral reef biological integrity held at the Caribbean Coral Reef Institute in La Parguera, Puerto Rico on August 21-22, 2012. The goals of this workshop were to:• Identify key qualitative and quantitative ecological characteristics (reef attributes) that determine the condition of linear coral reefs inhabiting shallow waters (<12 m) in southwestern Puerto Rico.• Use those reef attributes to recommend categorical condition rankings for establishing a biological condition gradient.• Ascertain through expert consensus those reef attributes that characterize biological integrity (a natural, fully-functioning system of organisms and communities) for coral reefs. • Develop a conceptual, narrative model that describes how biological attributes of coral reefs change along a gradient of increasing anthropogenic stress.The workshop brought together scientists with expertise in coral reef taxonomic groups (e.g., stony corals, fishes, sponges, gorgonians, algae, seagrasses and macroinvertebrates), as well as community structure, organism condition, ecosystem function and ecosystem connectivity. The experts evaluated photos and videos from 12 stations collected during EPA Coral Reef surveys (2010 & 2011) from Puerto Rico on coral reefs exhibiting a wide range of conditions. The experts individually rated each station as to observed condition (“good”, “fair” or “poor”) and documented their rationale for

Hurricanes, Coral Reefs and Rainforests: Resistance, Ruin and Recovery in the Caribbean

Treesearch

A. E. Lugo; C. S. Rogers; S. W Nixon

2000-01-01

The coexistence of hurricanes, coral reefs, and rainforests in the Caribbean demonstrates that highly structured ecosystems with great diversity can flourish in spite of recurring exposure to intense destructive energy. Coral reefs develop in response to wave energy and resist hurricanes largely by virtue of their structural strength. Limited fetch also protects some...

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.

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 assemblage changes produces the most accurate assessment of wave energy dissipation across the reef flat. However, the modelled results of bed roughness (e.g. 0.01 for the fore-reef slope) were different to the directly measured rugosity values (0.05 for the fore-reef slope) from three dimension structure-from-motion surveys. In spite of this, the modelled and directly measured values of roughness are similar considering the difficulties outlined in previous research when relating the coral reef structural complexity to a single value of hydrodynamic roughness. Bed roughness was shown to be a secondary factor behind wave breaking in dissipating wave energy. However, without bed friction waves could be an order of magnitude higher in the back-reef environment. Bed friction is also increasingly important in wave dissipation at higher sea levels as wave energy dissipation due to wave breaking is reduced at greater depths. This shows that maintaining a structurally diverse and healthy reef is crucial under future sea level rise scenarios in order to maintain the protection of coastal environments. These results also indicate that significant geomorphic change in coastal environments will occur due to reduced wave dissipation at higher sea levels unless reefs are capable of keeping up with forecasted sea level rise.

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…

Identifying and structuring objectives for a coral reef protection plan at the U.S. Environmental Protection Agency

EPA Science Inventory

Region 2 of the U.S. Environmental Protection Agency initiated a Coral Reef Protection Plan (CRPP) in 2014 to reduce anthropogenic stress on Caribbean coral reefs. The CRPP is intended to foster institutional practices that improve reef condition and focus regulatory and non-regu...

Impact Of Coral Structures On Wave Directional Spreading Across A Shallow Reef Flat - Lizard Island, Northern Great Barrier Reef

NASA Astrophysics Data System (ADS)

Leon, J. X.; Baldock, T.; Callaghan, D. P.; Hoegh-guldberg, O.; Mumby, P.; Phinn, S. R.; Roelfsema, C. M.; Saunders, M. I.

2013-12-01

Coral reef hydrodynamics operate at several and overlapping spatial-temporal scales. Waves have the most important forcing function on shallow (< 5 m) reefs as they drive most ecological and biogeochemical processes by exerting direct physical stress, directly mixing water (temperature and nutrients) and transporting sediments, nutrients and plankton. Reef flats are very effective at dissipating wave energy and providing an important ecosystem service by protecting highly valued shorelines. The effectiveness of reef flats to dissipate wave energy is related to the extreme hydraulic roughness of the benthos and substrate composition. Hydraulic roughness is usually obtained empirically from frictional-dissipation calculations, as detailed field measurements of bottom roughness (e.g. chain-method or profile gauges) is a very labour and time-consuming task. In this study we measured the impact of coral structures on wave directional spreading. Field data was collected during October 2012 across a reef flat on Lizard Island, northern Great Barrier Reef. Wave surface levels were measured using an array of self-logging pressure sensors. A rapid in situ close-range photogrammetric method was used to create a high-resolution (0.5 cm) image mosaic and digital elevation model. Individual coral heads were extracted from these datasets using geo-morphometric and object-based image analysis techniques. Wave propagation was modelled using a modified version of the SWAN model which includes the measured coral structures in 2m by 1m cells across the reef. The approach followed a cylinder drag approach, neglecting skin friction and inertial components. Testing against field data included bed skin friction. Our results show, for the first time, how the variability of the reef benthos structures affects wave dissipation across a shallow reef flat. This has important implications globally for coral reefs, due to the large extent of their area occupied by reef flats, particularly, as global-scale degradation in coral reef health is causing a lowering of reef carbonate production that might lead to a decrease in reef structure and roughness.

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 coral communities in the study area.

Balance of constructive and destructive carbonate processes on mesophotic coral reefs

NASA Astrophysics Data System (ADS)

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

2013-12-01

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

Clues to Coral Reef Ecosystem Health: Spectral Analysis Coupled with Radiative Transfer Modeling

NASA Astrophysics Data System (ADS)

Guild, L.; Ganapol, B.; Kramer, P.; Armstrong, R.; Gleason, A.; Torres, J.; Johnson, L.; Garfield, N.

2003-12-01

Coral reefs are among the world's most productive and biologically rich ecosystems and are some of the oldest ecosystems on Earth. Coralline structures protect coastlines from storms, maintain high diversity of marine life, and provide nurseries for marine species. Coral reefs play a role in carbon cycling through high rates of organic carbon metabolism and calcification. Coral reefs provide fisheries habitat that are the sole protein source for humans on remote islands. Reefs respond immediately to environmental change and therefore are considered "canaries" of the oceans. However, the world's reefs are in peril: they have shrunk 10-50% from their historical extent due to climate change and anthropogenic activity. An important contribution to coral reef research is improved spectral distinction of reef species' health where anthropogenic activity and climate change impacts are high. Relatively little is known concerning the spectral properties of coral or how coral structures reflect and transmit light. New insights into optical processes of corals under stressed conditions can lead to improved interpretation of airborne and satellite data and forecasting of immediate or long-term impacts of events such as bleaching and disease in coral. We are investigating the spatial and spectral resolution required to detect remotely changes in reef health by coupling spectral analysis of in situ spectra and airborne spectral data with a new radiative transfer model called CorMOD2. Challenges include light attenuation by the water column, atmospheric scattering, and scattering caused by the coral themselves that confound the spectral signal. In CorMOD2, input coral reflectance measurements produce modeled absorption through an inversion at each visible wavelength. The first model development phase of CorMOD2 imposes a scattering baseline that is constant regardless of coral condition, and further specifies that coral is optically thick. Evolution of CorMOD2 is towards a coral-specific radiative transfer model that includes coral biochemical concentrations, specific absorptivities of coral components, and transmission measurements from coral surfaces.

Linking Demographic Processes of Juvenile Corals to Benthic Recovery Trajectories in Two Common Reef Habitats

PubMed Central

Doropoulos, Christopher; Ward, Selina; Roff, George; González-Rivero, Manuel; Mumby, Peter J.

2015-01-01

Tropical reefs are dynamic ecosystems that host diverse coral assemblages with different life-history strategies. Here, we quantified how juvenile (<50 mm) coral demographics influenced benthic coral structure in reef flat and reef slope habitats on the southern Great Barrier Reef, Australia. Permanent plots and settlement tiles were monitored every six months for three years in each habitat. These environments exhibited profound differences: the reef slope was characterised by 95% less macroalgal cover, and twice the amount of available settlement substrata and rates of coral settlement than the reef flat. Consequently, post-settlement coral survival in the reef slope was substantially higher than that of the reef flat, and resulted in a rapid increase in coral cover from 7 to 31% in 2.5 years. In contrast, coral cover on the reef flat remained low (~10%), whereas macroalgal cover increased from 23 to 45%. A positive stock-recruitment relationship was found in brooding corals in both habitats; however, brooding corals were not directly responsible for the observed changes in coral cover. Rather, the rapid increase on the reef slope resulted from high abundances of broadcast spawning Acropora recruits. Incorporating our results into transition matrix models demonstrated that most corals escape mortality once they exceed 50 mm, but for smaller corals mortality in brooders was double those of spawners (i.e. acroporids and massive corals). For corals on the reef flat, sensitivity analysis demonstrated that growth and mortality of larger juveniles (21–50 mm) highly influenced population dynamics; whereas the recruitment, growth and mortality of smaller corals (<20 mm) had the highest influence on reef slope population dynamics. Our results provide insight into the population dynamics and recovery trajectories in disparate reef habitats, and highlight the importance of acroporid recruitment in driving rapid increases in coral cover following large-scale perturbation in reef slope environments. PMID:26009892

Linking demographic processes of juvenile corals to benthic recovery trajectories in two common reef habitats.

PubMed

Doropoulos, Christopher; Ward, Selina; Roff, George; González-Rivero, Manuel; Mumby, Peter J

2015-01-01

Tropical reefs are dynamic ecosystems that host diverse coral assemblages with different life-history strategies. Here, we quantified how juvenile (<50 mm) coral demographics influenced benthic coral structure in reef flat and reef slope habitats on the southern Great Barrier Reef, Australia. Permanent plots and settlement tiles were monitored every six months for three years in each habitat. These environments exhibited profound differences: the reef slope was characterised by 95% less macroalgal cover, and twice the amount of available settlement substrata and rates of coral settlement than the reef flat. Consequently, post-settlement coral survival in the reef slope was substantially higher than that of the reef flat, and resulted in a rapid increase in coral cover from 7 to 31% in 2.5 years. In contrast, coral cover on the reef flat remained low (~10%), whereas macroalgal cover increased from 23 to 45%. A positive stock-recruitment relationship was found in brooding corals in both habitats; however, brooding corals were not directly responsible for the observed changes in coral cover. Rather, the rapid increase on the reef slope resulted from high abundances of broadcast spawning Acropora recruits. Incorporating our results into transition matrix models demonstrated that most corals escape mortality once they exceed 50 mm, but for smaller corals mortality in brooders was double those of spawners (i.e. acroporids and massive corals). For corals on the reef flat, sensitivity analysis demonstrated that growth and mortality of larger juveniles (21-50 mm) highly influenced population dynamics; whereas the recruitment, growth and mortality of smaller corals (<20 mm) had the highest influence on reef slope population dynamics. Our results provide insight into the population dynamics and recovery trajectories in disparate reef habitats, and highlight the importance of acroporid recruitment in driving rapid increases in coral cover following large-scale perturbation in reef slope environments.

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

NASA Astrophysics Data System (ADS)

Hochberg, E. J.

2016-02-01

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

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.

Three decades of recurrent declines and recoveries in corals belie ongoing change in fish assemblages

NASA Astrophysics Data System (ADS)

Lamy, T.; Galzin, R.; Kulbicki, M.; Lison de Loma, T.; Claudet, J.

2016-03-01

Coral reefs are increasingly being altered by a myriad of anthropogenic activities and natural disturbances. Long-term studies offer unique opportunities to understand how multiple and recurrent disturbances can influence coral reef resilience and long-term dynamics. While the long-term dynamics of coral assemblages have been extensively documented, the long-term dynamics of coral reef fish assemblages have received less attention. Here, we describe the changes in fish assemblages on Tiahura reef, Moorea, from 1979 to 2011. During this 33-yr period, Tiahura was exposed to multiple disturbances (crown-of-thorns seastar outbreaks and cyclones) that caused recurrent declines and recoveries of coral cover and changes in the dominant coral genera. These shifts in coral composition were associated with long-term cascading effects on fish assemblages. The composition and trophic structure of fish assemblages continuously shifted without returning to their initial composition, whereas fish species richness remained stable, albeit with a small increase over time. We detected nonlinear responses of fish density when corals were most degraded. When coral cover dropped below 10 % following a severe crown-of-thorns sea star outbreak, the density of most fish trophic groups sharply decreased. Our study shows that historical contingency may potentially be an important but largely underestimated factor explaining the contemporary structure of reef fish assemblages and suggests that temporal stability in their structure and function should not necessarily be the target of management strategies that aim at increasing or maintaining coral reef resilience.

Hurricanes, coral reefs and rainforests: resistance, ruin and recovery in the Caribbean

USGS Publications Warehouse

Lugo, Ariel E.; Rogers, Caroline S.; Nixon, Scott W.

2000-01-01

The coexistence of hurricanes, coral reefs, and rainforests in the Caribbean demonstrates that highly structured ecosystems with great diversity can flourish in spite of recurring exposure to intense destructive energy. Coral reefs develop in response to wave energy and resist hurricanes largely by virtue of their structural strength. Limited fetch also protects some reefs from fully developed hurricane waves. While storms may produce dramatic local reef damage, they appear to have little impact on the ability of coral reefs to provide food or habitat for fish and other animals. Rainforests experience an enormous increase in wind energy during hurricanes with dramatic structural changes in the vegetation. The resulting changes in forest microclimate are larger than those on reefs and the loss of fruit, leaves, cover, and microclimate has a great impact on animal populations. Recovery of many aspects of rainforest structure and function is rapid, though there may be long-term changes in species composition. While resistance and repair have maintained reefs and rainforests in the past, human impacts may threaten their ability to survive.

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.

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 residual wave energy transported to the coast may result in the alteration of alongshore sediment transport gradients and substantial changes to coastal morphology.

Post-bleaching coral community change on southern Maldivian reefs: is there potential for rapid recovery?

NASA Astrophysics Data System (ADS)

Perry, C. T.; Morgan, K. M.

2017-12-01

Given the severity of the 2016 global bleaching event, there are major questions about how quickly reef communities will recover. Here, we explore the ecological and physical structural changes that occurred across five atoll interior reefs in the southern Maldives using data collected at 6 and 12 months post-bleaching. Following initial severe coral mortality, further minor coral mortality had occurred by 12 months post-bleaching, and coral cover is now low (<6%). In contrast, reef rugosity has continued to decline over time, and our observations suggest transitions to rubble-dominated states will occur in the near future. Juvenile coral densities in shallow fore-reef habitats are also exceptionally low (<6 individuals m-2), well below those measured 9-12 months following the 1998 bleaching event, and below recovery thresholds identified on other Indian Ocean reefs. Our findings suggest that the physical structure of these reefs will need to decline further before effective recruitment and recovery can begin.

iss009e23808

NASA Image and Video Library

2004-09-20

ISS009-E-23808 (20 September 2004) --- A fringing coral reef in the Red Sea is featured in this image photographed by an Expedition 9 crewmember on the International Space Station (ISS). The Sudanese coast of the Red Sea is a well known destination for divers due to clear water and abundance of coral reefs (or “shia’ab” in Arabic). According to NASA scientists studying the ISS imagery, reefs are formed primarily from precipitation of calcium carbonate by corals; massive reef structures are built over thousands of years of succeeding generations of coral. In the Red Sea, fringing reefs form on shallow shelves of less than 50 meters depth along the coastline. This photograph illustrates the intricate morphology of the reef system located along the coast between Port Sudan to the northwest and the Tokar River delta to the southeast. Close to shore, fringing reefs border the coastline. Farther offshore grows a larger, more complicated barrier reef structure. Different parts of the reef structure show up as variable shades of light blue. Deeper water channels (darker blue) define the boundaries for individual reefs within the greater barrier reef system. Such a complex pattern of reefs may translate into greater ecosystem diversity through a wide variety of local reef environments.

The influence of coral reef benthic condition on associated fish assemblages.

PubMed

Chong-Seng, Karen M; Mannering, Thomas D; Pratchett, Morgan S; Bellwood, David R; Graham, Nicholas A J

2012-01-01

Accumulative disturbances can erode a coral reef's resilience, often leading to replacement of scleractinian corals by macroalgae or other non-coral organisms. These degraded reef systems have been mostly described based on changes in the composition of the reef benthos, and there is little understanding of how such changes are influenced by, and in turn influence, other components of the reef ecosystem. This study investigated the spatial variation in benthic communities on fringing reefs around the inner Seychelles islands. Specifically, relationships between benthic composition and the underlying substrata, as well as the associated fish assemblages were assessed. High variability in benthic composition was found among reefs, with a gradient from high coral cover (up to 58%) and high structural complexity to high macroalgae cover (up to 95%) and low structural complexity at the extremes. This gradient was associated with declining species richness of fishes, reduced diversity of fish functional groups, and lower abundance of corallivorous fishes. There were no reciprocal increases in herbivorous fish abundances, and relationships with other fish functional groups and total fish abundance were weak. Reefs grouping at the extremes of complex coral habitats or low-complexity macroalgal habitats displayed markedly different fish communities, with only two species of benthic invertebrate feeding fishes in greater abundance in the macroalgal habitat. These results have negative implications for the continuation of many coral reef ecosystem processes and services if more reefs shift to extreme degraded conditions dominated by macroalgae.

Conservation genetics and the resilience of reef-building corals.

PubMed

van Oppen, Madeleine J H; Gates, Ruth D

2006-11-01

Coral reefs have suffered long-term decline due to a range of anthropogenic disturbances and are now also under threat from climate change. For appropriate management of these vulnerable and valuable ecosystems it is important to understand the factors and processes that determine their resilience and that of the organisms inhabiting them, as well as those that have led to existing patterns of coral reef biodiversity. The scleractinian (stony) corals deposit the structural framework that supports and promotes the maintenance of biological diversity and complexity of coral reefs, and as such, are major components of these ecosystems. The success of reef-building corals is related to their obligate symbiotic association with dinoflagellates of the genus Symbiodinium. These one-celled algal symbionts (zooxanthellae) live in the endodermal tissues of their coral host, provide most of the host's energy budget and promote rapid calcification. Furthermore, zooxanthellae are the main primary producers on coral reefs due to the oligotrophic nature of the surrounding waters. In this review paper, we summarize and critically evaluate studies that have employed genetics and/or molecular biology in examining questions relating to the evolution and ecology of reef-building corals and their algal endosymbionts, and that bear relevance to coral reef conservation. We discuss how these studies can focus future efforts, and examine how these approaches enhance our understanding of the resilience of reef-building corals.

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. Copyright © 2015, American Association for the Advancement of Science.

Fringing coral reef condition decline: assembling the puzzle of human impact associated to coastal development.

NASA Astrophysics Data System (ADS)

Garza-Perez, J. R.; Lopez-Patoni, A.; Naranjo-Garcia, M. J.

2014-12-01

Coral cover at Akumal fringing coral reef decreased 50% in a 13 yr. period, while the adjacent coastal zone increased its human-modified surface (associated to urban-tourist development) in 192%. In the same period, the number of local residents only increased 20% (1088 to1362) but the visitors did in 50% from ca. 200,000 to ca. 300,000. In this coastal zone, the phreatic acts as a storage of nutrients and pollutants from sources related to human activity, thus having a chronic run-off towards the reef, with acute episodes during the rainy season, specially during the anomalous rainy season of 2013. Using videotransects for monitoring the benthic reef components, changes were detected: from 2000 to 2013 the algae cover increased 166%, the reef condition and the reef structure indexes decreased in 50%, and coral diseases incidence increased 25% after a spike increment of 150% in 2010. The role of anthropogenic-stress indicators (population, modified land area, nutrients) was explored along reef condition indicators (reef structure and diversity indexes, topographic complexity, benthic cover and coral diseases incidence) via spatial analysis and multivariate statistics. Spatial patterns of the change in reef condition derived from high-resolution satellite imagery also provided insight for the stressors analysis and their relationships along the study period. Stress indicators (land-modified area and population) are correlated to decreases in coral cover and in reef structure. Direct stressors as sedimentation, nutrients and pollutants seem to be related to the decrease in overall reef condition, although time-series data is lacking; the contextual interpretation of their effects, paired with benthic condition characteristics suggest a strong relationship between these stressors and the decrease in the condition of the reef.

Comparison of Commercial Structure-From Photogrammety Software Used for Underwater Three-Dimensional Modeling of Coral Reef Environments

NASA Astrophysics Data System (ADS)

Burns, J. H. R.; Delparte, D.

2017-02-01

Structural complexity in ecosystems creates an assortment of microhabitat types and has been shown to support greater diversity and abundance of associated organisms. The 3D structure of an environment also directly affects important ecological parameters such as habitat provisioning and light availability and can therefore strongly influence ecosystem function. Coral reefs are architecturally complex 3D habitats, whose structure is intrinsically linked to the ecosystem biodiversity, productivity, and function. The field of coral ecology has, however, been primarily limited to using 2-dimensional (2D) planar survey techniques for studying the physical structure of reefs. This conventional approach fails to capture or quantify the intricate structural complexity of corals that influences habitat facilitation and biodiversity. A 3-dimensional (3D) approach can obtain accurate measurements of architectural complexity, topography, rugosity, volume, and other structural characteristics that affect biodiversity and abundance of reef organisms. Structurefrom- Motion (SfM) photogrammetry is an emerging computer vision technology that provides a simple and cost-effective method for 3D reconstruction of natural environments. SfM has been used in several studies to investigate the relationship between habitat complexity and ecological processes in coral reef ecosystems. This study compared two commercial SfM software packages, Agisoft Photoscan Pro and Pix4Dmapper Pro 3.1, in order to assess the cpaability and spatial accuracy of these programs for conducting 3D modeling of coral reef habitats at three spatial scales.

Evidence from aerial photography of structural loss of coral reefs at Barbados, West Indies

NASA Astrophysics Data System (ADS)

Lewis, J.

2002-04-01

In response to concerns about widespread degradation of coral reefs at Barbados, West Indies, over the past two decades, maps and planimetric areas of 20 fringing coral reefs were estimated from enlargements of aerial photographs of the island, using geographic information system analysis. There were statistically significant reductions in reef areas over a 40-year period from 1950 to 1991. Areal losses exceeding measurement and boundary interpretation errors of 10% were detected on eight of the 20 reefs. Ground validation carried out by divers on six of the reefs confirmed physical losses of reef structures and accumulation of rubble and sand substrata at sites where substantial planimetric area loss was detected on aerial photographs. Structural losses occurred along the "spur and groove" system of the reef-seaward edge, within deep channels or breaches in the reef front, and along the flanks or ends of reefs. The location and nature of the observed losses suggest that storm damage and seasonal alterations in beach morphology are the two most important factors contributing to geomorphological structural loss of the reefs.

The Use of Simulated Visible/Infrared Imager/Radiometer Suite (VIIRS) and Landsat Data Continuity Mission (LDCM) Imagery for Coral Reef Monitoring

NASA Technical Reports Server (NTRS)

Estep, L.; Spruce, J.; Blonski, S.; Moore, R.

2008-01-01

Coral reefs are some of the most biologically rich and economically important ecosystems on Earth. Coral reefs are Earth's largest biological structures and have taken thousands of years to form. Coral reefs not only provide important habitat for many marine animals and plants, but they also provide humanity with food, jobs, chemicals, protection against storms, and life-saving pharmaceuticals. Severe bleaching events have occurred that have dramatic long-term ecological impacts to corals, including loss of reef-building corals, changes in benthic habitat, and, in some cases, changes in larval fish populations (Holden and Ledrew, 1998). Some researchers suggest that 10 percent of Earth s coral reefs have already been destroyed and that another 60 percent are in danger. Scientists have proposed that as much as 95 percent of Jamaica's reefs are dying or dead. This poster reports on a Rapid Prototyping Capability (RPC) experiment done to determine whether future NASA sensors - the Visible/Infrared Imager/Radiometer Suite (VIIRS) and Landsat Data Continuity Mission (LDCM) - could generate key data products for the Integrated Coral Reef Observation Network (ICON)/Coral Reef Early Warning System (CREWS) Decision Support Tool (DST) operated by the National Oceanic and Atmospheric Administration (NOAA).

Lithifying Microbes Associated to Coral Rubbles

NASA Astrophysics Data System (ADS)

Beltran, Y.

2015-12-01

Microbial communities taking part in calcium carbonate lithification processes are particularly relevant to coral reef formation in as much as this lithification allows the stabilization of secondary reef structure. This second framework promotes long-term permanence of the reef, favoring the establishment of macro-reef builders, including corals. The reef-bacterial crusts formed by microbial communities are composed of magnesium calcite. Although prokaryotes are not proper calcifiers, carbonate precipitation can be induced by their metabolic activity and EPS production. Coral reefs are rapidly declining due to several variables associated to environmental change. Specifically in the Caribbean, stony coral Acropora palmata have suffered damage due to diseases, bleaching and storms. Some reports show that in highly disturbed areas wide ridges of reef rubbles are formed by biological and physical lithification. In this study we explore microbial diversity associated to lithified rubbles left after the great decline of reef-building A. palmata.

ASSESSMENT OF CORAL CONDITION

EPA Science Inventory

Complex reef structures formed by calcified coral skeletons provide a physical habitat that produces highly-valued ecosystem services, including shoreline protection and a high diversity and abundance of marine organisms that support lucrative fishing and tourism. Yet, coral reef...

Coral community response to bleaching on a highly disturbed reef

PubMed Central

Guest, J. R.; Low, J.; Tun, K.; Wilson, B.; Ng, C.; Raingeard, D.; Ulstrup, K. E.; Tanzil, J. T. I.; Todd, P. A.; Toh, T. C.; McDougald, D.; Chou, L. M.; Steinberg, P. D.

2016-01-01

While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress. PMID:26876092

Coral community response to bleaching on a highly disturbed reef.

PubMed

Guest, J R; Low, J; Tun, K; Wilson, B; Ng, C; Raingeard, D; Ulstrup, K E; Tanzil, J T I; Todd, P A; Toh, T C; McDougald, D; Chou, L M; Steinberg, P D

2016-02-15

While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.

Coral community response to bleaching on a highly disturbed reef

NASA Astrophysics Data System (ADS)

Guest, J. R.; Low, J.; Tun, K.; Wilson, B.; Ng, C.; Raingeard, D.; Ulstrup, K. E.; Tanzil, J. T. I.; Todd, P. A.; Toh, T. C.; McDougald, D.; Chou, L. M.; Steinberg, P. D.

2016-02-01

While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.

The Influence of Coral Reef Benthic Condition on Associated Fish Assemblages

PubMed Central

Chong-Seng, Karen M.; Mannering, Thomas D.; Pratchett, Morgan S.; Bellwood, David R.; Graham, Nicholas A. J.

2012-01-01

Accumulative disturbances can erode a coral reef’s resilience, often leading to replacement of scleractinian corals by macroalgae or other non-coral organisms. These degraded reef systems have been mostly described based on changes in the composition of the reef benthos, and there is little understanding of how such changes are influenced by, and in turn influence, other components of the reef ecosystem. This study investigated the spatial variation in benthic communities on fringing reefs around the inner Seychelles islands. Specifically, relationships between benthic composition and the underlying substrata, as well as the associated fish assemblages were assessed. High variability in benthic composition was found among reefs, with a gradient from high coral cover (up to 58%) and high structural complexity to high macroalgae cover (up to 95%) and low structural complexity at the extremes. This gradient was associated with declining species richness of fishes, reduced diversity of fish functional groups, and lower abundance of corallivorous fishes. There were no reciprocal increases in herbivorous fish abundances, and relationships with other fish functional groups and total fish abundance were weak. Reefs grouping at the extremes of complex coral habitats or low-complexity macroalgal habitats displayed markedly different fish communities, with only two species of benthic invertebrate feeding fishes in greater abundance in the macroalgal habitat. These results have negative implications for the continuation of many coral reef ecosystem processes and services if more reefs shift to extreme degraded conditions dominated by macroalgae. PMID:22870294

Predator crown-of-thorns starfish (Acanthaster planci) outbreak, mass mortality of corals, and cascading effects on reef fish and benthic communities.

PubMed

Kayal, Mohsen; Vercelloni, Julie; Lison de Loma, Thierry; Bosserelle, Pauline; Chancerelle, Yannick; Geoffroy, Sylvie; Stievenart, Céline; Michonneau, François; Penin, Lucie; Planes, Serge; Adjeroud, Mehdi

2012-01-01

Outbreaks of the coral-killing seastar Acanthaster planci are intense disturbances that can decimate coral reefs. These events consist of the emergence of large swarms of the predatory seastar that feed on reef-building corals, often leading to widespread devastation of coral populations. While cyclic occurrences of such outbreaks are reported from many tropical reefs throughout the Indo-Pacific, their causes are hotly debated, and the spatio-temporal dynamics of the outbreaks and impacts to reef communities remain unclear. Based on observations of a recent event around the island of Moorea, French Polynesia, we show that Acanthaster outbreaks are methodic, slow-paced, and diffusive biological disturbances. Acanthaster outbreaks on insular reef systems like Moorea's appear to originate from restricted areas confined to the ocean-exposed base of reefs. Elevated Acanthaster densities then progressively spread to adjacent and shallower locations by migrations of seastars in aggregative waves that eventually affect the entire reef system. The directional migration across reefs appears to be a search for prey as reef portions affected by dense seastar aggregations are rapidly depleted of living corals and subsequently left behind. Coral decline on impacted reefs occurs by the sequential consumption of species in the order of Acanthaster feeding preferences. Acanthaster outbreaks thus result in predictable alteration of the coral community structure. The outbreak we report here is among the most intense and devastating ever reported. Using a hierarchical, multi-scale approach, we also show how sessile benthic communities and resident coral-feeding fish assemblages were subsequently affected by the decline of corals. By elucidating the processes involved in an Acanthaster outbreak, our study contributes to comprehending this widespread disturbance and should thus benefit targeted management actions for coral reef ecosystems.

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.

Changes in coral reef communities across a natural gradient in seawater pH.

PubMed

Barkley, Hannah C; Cohen, Anne L; Golbuu, Yimnang; Starczak, Victoria R; DeCarlo, Thomas M; Shamberger, Kathryn E F

2015-06-01

Ocean acidification threatens the survival of coral reef ecosystems worldwide. The negative effects of ocean acidification observed in many laboratory experiments have been seen in studies of naturally low-pH reefs, with little evidence to date for adaptation. Recently, we reported initial data suggesting that low-pH coral communities of the Palau Rock Islands appear healthy despite the extreme conditions in which they live. Here, we build on that observation with a comprehensive statistical analysis of benthic communities across Palau's natural acidification gradient. Our analysis revealed a shift in coral community composition but no impact of acidification on coral richness, coralline algae abundance, macroalgae cover, coral calcification, or skeletal density. However, coral bioerosion increased 11-fold as pH decreased from the barrier reefs to the Rock Island bays. Indeed, a comparison of the naturally low-pH coral reef systems studied so far revealed increased bioerosion to be the only consistent feature among them, as responses varied across other indices of ecosystem health. Our results imply that whereas community responses may vary, escalation of coral reef bioerosion and acceleration of a shift from net accreting to net eroding reef structures will likely be a global signature of ocean acidification.

Size structuring and allometric scaling relationships in coral reef fishes.

PubMed

Dunic, Jillian C; Baum, Julia K

2017-05-01

Temperate marine fish communities are often size-structured, with predators consuming increasingly larger prey and feeding at higher trophic levels as they grow. Gape limitation and ontogenetic diet shifts are key mechanisms by which size structuring arises in these communities. Little is known, however, about size structuring in coral reef fishes. Here, we aimed to advance understanding of size structuring in coral reef food webs by examining the evidence for these mechanisms in two groups of reef predators. Given the diversity of feeding modes amongst coral reef fishes, we also compared gape size-body size allometric relationships across functional groups to determine whether they are reliable indicators of size structuring. We used gut content analysis and quantile regressions of predator size-prey size relationships to test for evidence of gape limitation and ontogenetic niche shifts in reef piscivores (n = 13 species) and benthic invertivores (n = 3 species). We then estimated gape size-body size allometric scaling coefficients for 21 different species from four functional groups, including herbivores/detritivores, which are not expected to be gape-limited. We found evidence of both mechanisms for size structuring in coral reef piscivores, with maximum prey size scaling positively with predator body size, and ontogenetic diet shifts including prey type and expansion of prey size. There was, however, little evidence of size structuring in benthic invertivores. Across species and functional groups, absolute and relative gape sizes were largest in piscivores as expected, but gape size-body size scaling relationships were not indicative of size structuring. Instead, relative gape sizes and mouth morphologies may be better indicators. Our results provide evidence that coral reef piscivores are size-structured and that gape limitation and ontogenetic niche shifts are the mechanisms from which this structure arises. Although gape allometry was not indicative of size structuring, it may have implications for ecosystem function: positively allometric gape size-body size scaling relationships in herbivores/detritivores suggests that loss of large-bodied individuals of these species will have a disproportionately negative impact on reef grazing pressure. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Protein expression and genetic structure of the coral Porites lobata in an environmentally extreme Samoan back reef: Does host genotype limit phenotypic plasticity?

USGS Publications Warehouse

Barshis, D.J.; Stillman, J.H.; Gates, R.D.; Toonen, R.J.; Smith, L.W.; Birkeland, C.

2010-01-01

The degree to which coral reef ecosystems will be impacted by global climate change depends on regional and local differences in corals' susceptibility and resilience to environmental stressors. Here, we present data from a reciprocal transplant experiment using the common reef building coral Porites lobata between a highly fluctuating back reef environment that reaches stressful daily extremes, and a more stable, neighbouring forereef. Protein biomarker analyses assessing physiological contributions to stress resistance showed evidence for both fixed and environmental influence on biomarker response. Fixed influences were strongest for ubiquitin-conjugated proteins with consistently higher levels found in back reef source colonies both pre and post-transplant when compared with their forereef conspecifics. Additionally, genetic comparisons of back reef and forereef populations revealed significant population structure of both the nuclear ribosomal and mitochondrial genomes of the coral host (FST = 0.146 P < 0.0001, FST = 0.335 P < 0.0001 for rDNA and mtDNA, respectively), whereas algal endosymbiont populations were genetically indistinguishable between the two sites. We propose that the genotype of the coral host may drive limitations to the physiological responses of these corals when faced with new environmental conditions. This result is important in understanding genotypic and environmental interactions in the coral algal symbiosis and how corals may respond to future environmental changes. ?? 2010 Blackwell Publishing Ltd.

Boring sponges, an increasing threat for coral reefs affected by bleaching events.

PubMed

Carballo, José L; Bautista, Eric; Nava, Héctor; Cruz-Barraza, José A; Chávez, Jesus A

2013-04-01

Coral bleaching is a stress response of corals induced by a variety of factors, but these events have become more frequent and intense in response to recent climate-change-related temperature anomalies. We tested the hypothesis that coral reefs affected by bleaching events are currently heavily infested by boring sponges, which are playing a significant role in the destruction of their physical structure. Seventeen reefs that cover the entire distributional range of corals along the Mexican Pacific coast were studied between 2005/2006, and later between 2009/2010. Most of these coral reefs were previously impacted by bleaching events, which resulted in coral mortalities. Sponge abundance and species richness was used as an indicator of bioerosion, and coral cover was used to describe the present condition of coral reefs. Coral reefs are currently highly invaded (46% of the samples examined) by a very high diversity of boring sponges (20 species); being the coral reef framework the substrate most invaded (56%) followed by the rubbles (45%), and the living colonies (36%). The results also indicated that boring sponges are promoting the dislodgment of live colonies and large fragments from the framework. In summary, the eastern coral reefs affected by bleaching phenomena, mainly provoked by El Niño, present a high diversity and abundance of boring sponges, which are weakening the union of the colony with the reef framework and promoting their dislodgment. These phenomena will probably become even more intense and severe, as temperatures are projected to continue to rise under the scenarios for future climate change, which could place many eastern coral reefs beyond their survival threshold.

Boring sponges, an increasing threat for coral reefs affected by bleaching events

PubMed Central

Carballo, José L; Bautista, Eric; Nava, Héctor; Cruz-Barraza, José A; Chávez, Jesus A

2013-01-01

Coral bleaching is a stress response of corals induced by a variety of factors, but these events have become more frequent and intense in response to recent climate-change-related temperature anomalies. We tested the hypothesis that coral reefs affected by bleaching events are currently heavily infested by boring sponges, which are playing a significant role in the destruction of their physical structure. Seventeen reefs that cover the entire distributional range of corals along the Mexican Pacific coast were studied between 2005/2006, and later between 2009/2010. Most of these coral reefs were previously impacted by bleaching events, which resulted in coral mortalities. Sponge abundance and species richness was used as an indicator of bioerosion, and coral cover was used to describe the present condition of coral reefs. Coral reefs are currently highly invaded (46% of the samples examined) by a very high diversity of boring sponges (20 species); being the coral reef framework the substrate most invaded (56%) followed by the rubbles (45%), and the living colonies (36%). The results also indicated that boring sponges are promoting the dislodgment of live colonies and large fragments from the framework. In summary, the eastern coral reefs affected by bleaching phenomena, mainly provoked by El Niño, present a high diversity and abundance of boring sponges, which are weakening the union of the colony with the reef framework and promoting their dislodgment. These phenomena will probably become even more intense and severe, as temperatures are projected to continue to rise under the scenarios for future climate change, which could place many eastern coral reefs beyond their survival threshold. PMID:23610632

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.

Differential Impacts of Land-Based Sources of Pollution on the Microbiota of Southeast Florida Coral Reefs

PubMed Central

Staley, Christopher; Kaiser, Thomas; Gidley, Maribeth L.; Enochs, Ian C.; Jones, Paul R.; Goodwin, Kelly D.; Sinigalliano, Christopher D.

2017-01-01

ABSTRACT Coral reefs are dynamic ecosystems known for decades to be endangered due, in large part, to anthropogenic impacts from land-based sources of pollution (LBSP). In this study, we utilized an Illumina-based next-generation sequencing approach to characterize prokaryotic and fungal communities from samples collected off the southeast coast of Florida. Water samples from coastal inlet discharges, oceanic outfalls of municipal wastewater treatment plants, treated wastewater effluent before discharge, open ocean samples, and coral tissue samples (mucus and polyps) were characterized to determine the relationships between microbial communities in these matrices and those in reef water and coral tissues. Significant differences in microbial communities were noted among all sample types but varied between sampling areas. Contamination from outfalls was found to be the greatest potential source of LBSP influencing native microbial community structure among all reef samples, although pollution from inlets was also noted. Notably, reef water and coral tissue communities were found to be more greatly impacted by LBSP at southern reefs, which also experienced the most degradation during the course of the study. The results of this study provide new insights into how microbial communities from LBSP can impact coral reefs in southeast Florida and suggest that wastewater outfalls may have a greater influence on the microbial diversity and structure of these reef communities than do contaminants carried in runoff, although the influences of runoff and coastal inlet discharge on coral reefs are still substantial. IMPORTANCE Coral reefs are known to be endangered due to sewage discharge and to runoff of nutrients, pesticides, and other substances associated with anthropogenic activity. Here, we used next-generation sequencing to characterize the microbial communities of potential contaminant sources in order to determine how environmental discharges of microbiota and their genetic material may influence the microbiomes of coral reef communities and coastal receiving waters. Runoff delivered through inlet discharges impacted coral microbial communities, but impacts from oceanic outfalls carrying treated wastewater were greater. Geographic differences in the degree of impact suggest that coral microbiomes may be influenced by the microbiological quality of treated wastewater. PMID:28341673

Differential Impacts of Land-Based Sources of Pollution on the Microbiota of Southeast Florida Coral Reefs.

PubMed

Staley, Christopher; Kaiser, Thomas; Gidley, Maribeth L; Enochs, Ian C; Jones, Paul R; Goodwin, Kelly D; Sinigalliano, Christopher D; Sadowsky, Michael J; Chun, Chan Lan

2017-05-15

Coral reefs are dynamic ecosystems known for decades to be endangered due, in large part, to anthropogenic impacts from land-based sources of pollution (LBSP). In this study, we utilized an Illumina-based next-generation sequencing approach to characterize prokaryotic and fungal communities from samples collected off the southeast coast of Florida. Water samples from coastal inlet discharges, oceanic outfalls of municipal wastewater treatment plants, treated wastewater effluent before discharge, open ocean samples, and coral tissue samples (mucus and polyps) were characterized to determine the relationships between microbial communities in these matrices and those in reef water and coral tissues. Significant differences in microbial communities were noted among all sample types but varied between sampling areas. Contamination from outfalls was found to be the greatest potential source of LBSP influencing native microbial community structure among all reef samples, although pollution from inlets was also noted. Notably, reef water and coral tissue communities were found to be more greatly impacted by LBSP at southern reefs, which also experienced the most degradation during the course of the study. The results of this study provide new insights into how microbial communities from LBSP can impact coral reefs in southeast Florida and suggest that wastewater outfalls may have a greater influence on the microbial diversity and structure of these reef communities than do contaminants carried in runoff, although the influences of runoff and coastal inlet discharge on coral reefs are still substantial. IMPORTANCE Coral reefs are known to be endangered due to sewage discharge and to runoff of nutrients, pesticides, and other substances associated with anthropogenic activity. Here, we used next-generation sequencing to characterize the microbial communities of potential contaminant sources in order to determine how environmental discharges of microbiota and their genetic material may influence the microbiomes of coral reef communities and coastal receiving waters. Runoff delivered through inlet discharges impacted coral microbial communities, but impacts from oceanic outfalls carrying treated wastewater were greater. Geographic differences in the degree of impact suggest that coral microbiomes may be influenced by the microbiological quality of treated wastewater. Copyright © 2017 Staley et al.

Human activities as a driver of spatial variation in the trophic structure of fish communities on Pacific coral reefs.

PubMed

Ruppert, Jonathan L W; Vigliola, Laurent; Kulbicki, Michel; Labrosse, Pierre; Fortin, Marie-Josée; Meekan, Mark G

2018-01-01

Anthropogenic activities such as land-use change, pollution and fishing impact the trophic structure of coral reef fishes, which can influence ecosystem health and function. Although these impacts may be ubiquitous, they are not consistent across the tropical Pacific Ocean. Using an extensive database of fish biomass sampled using underwater visual transects on coral reefs, we modelled the impact of human activities on food webs at Pacific-wide and regional (1,000s-10,000s km) scales. We found significantly lower biomass of sharks and carnivores, where there were higher densities of human populations (hereafter referred to as human activity); however, these patterns were not spatially consistent as there were significant differences in the trophic structures of fishes among biogeographic regions. Additionally, we found significant changes in the benthic structure of reef environments, notably a decline in coral cover where there was more human activity. Direct human impacts were the strongest in the upper part of the food web, where we found that in a majority of the Pacific, the biomass of reef sharks and carnivores were significantly and negatively associated with human activity. Finally, although human-induced stressors varied in strength and significance throughout the coral reef food web across the Pacific, socioeconomic variables explained more variation in reef fish trophic structure than habitat variables in a majority of the biogeographic regions. Notably, economic development (measured as GDP per capita) did not guarantee healthy reef ecosystems (high coral cover and greater fish biomass). Our results indicate that human activities are significantly shaping patterns of trophic structure of reef fishes in a spatially nonuniform manner across the Pacific Ocean, by altering processes that organize communities in both "top-down" (fishing of predators) and "bottom-up" (degradation of benthic communities) contexts. © 2017 John Wiley & Sons Ltd.

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. © 2012 Blackwell Publishing Ltd/CNRS.

Extinction rate, historical population structure and ecological role of the Caribbean monk seal.

PubMed

McClenachan, Loren; Cooper, Andrew B

2008-06-22

The productivity and biomass of pristine coral reef ecosystems is poorly understood, particularly in the Caribbean where communities have been impacted by overfishing and multiple other stressors over centuries. Using historical data on the spatial distribution and abundance of the extinct Caribbean monk seal (Monachus tropicalis), this study reconstructs the population size, structure and ecological role of this once common predator within coral reef communities, and provides evidence that historical reefs supported biomasses of fishes and invertebrates up to six times greater than those found on typical modern Caribbean reefs. An estimated 233,000-338,000 monk seals were distributed among 13 colonies across the Caribbean. The biomass of reef fishes and invertebrates required to support historical seal populations was 732-1018 gm(-2) of reefs, which exceeds that found on any Caribbean reef today and is comparable with those measured in remote Pacific reefs. Quantitative estimates of historically dense monk seal colonies and their consumption rates on pristine reefs provide concrete data on the magnitude of decline in animal biomass on Caribbean coral reefs. Realistic reconstruction of these past ecosystems is critical to understanding the profound and long-lasting effect of human hunting on the functioning of coral reef ecosystems.

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. © 2012 Society for Conservation Biology.

Coral reef recovery dynamics in a changing world

NASA Astrophysics Data System (ADS)

Graham, N. A. J.; Nash, K. L.; Kool, J. T.

2011-06-01

Coral reef ecosystems are degrading through multiple disturbances that are becoming more frequent and severe. The complexities of this degradation have been studied in detail, but little work has assessed characteristics that allow reefs to bounce back and recover between pulse disturbance events. We quantitatively review recovery rates of coral cover from pulse disturbance events among 48 different reef locations, testing the relative roles of disturbance characteristics, reef characteristics, connectivity and anthropogenic influences. Reefs in the western Pacific Ocean had the fastest recovery, whereas reefs in the geographically isolated eastern Pacific Ocean were slowest to recover, reflecting regional differences in coral composition, fish functional diversity and geographic isolation. Disturbances that opened up large areas of benthic space recovered quickly, potentially because of nonlinear recovery where recruitment rates were high. The type of disturbance had a limited effect on subsequent rates of reef recovery, although recovery was faster following crown-of-thorns starfish outbreaks. This inconsequential role of disturbance type may be in part due to the role of unaltered structural complexity in maintaining key reef processes, such as recruitment and herbivory. Few studies explicitly recorded potential ecological determinants of recovery, such as recruitment rates, structural complexity of habitat and the functional composition of reef-associated fish. There was some evidence of slower recovery rates within protected areas compared with other management systems and fished areas, which may reflect the higher initial coral cover in protected areas rather than reflecting a management effect. A better understanding of the driving role of processes, structural complexity and diversity on recovery may enable more appropriate management actions that support coral-dominated ecosystems in our changing climate.

Ecosystem regime shifts disrupt trophic structure.

PubMed

Hempson, Tessa N; Graham, Nicholas A J; MacNeil, M Aaron; Hoey, Andrew S; Wilson, Shaun K

2018-01-01

Regime shifts between alternative stable ecosystem states are becoming commonplace due to the combined effects of local stressors and global climate change. Alternative states are characterized as substantially different in form and function from pre-disturbance states, disrupting the delivery of ecosystem services and functions. On coral reefs, regime shifts are typically characterized by a change in the benthic composition from coral to macroalgal dominance. Such fundamental shifts in the benthos are anticipated to impact associated fish communities that are reliant on the reef for food and shelter, yet there is limited understanding of how regime shifts propagate through the fish community over time, relative to initial or recovery conditions. This study addresses this knowledge gap using long-term data of coral reef regime shifts and recovery on Seychelles reefs following the 1998 mass bleaching event. It shows how trophic structure of the reef fish community becomes increasingly dissimilar between alternative reef ecosystem states (regime-shifted vs. recovering) with time since disturbance. Regime-shifted reefs developed a concave trophic structure, with increased biomass in base trophic levels as herbivorous species benefitted from increased algal resources. Mid trophic level species, including specialists such as corallivores, declined with loss of coral habitat, while biomass was retained in upper trophic levels by large-bodied, generalist invertivores. Recovering reefs also experienced an initial decline in mid trophic level biomass, but moved toward a bottom-heavy pyramid shape, with a wide range of feeding groups (e.g., planktivores, corallivores, omnivores) represented at mid trophic levels. Given the importance of coral reef fishes in maintaining the ecological function of coral reef ecosystems and their associated fisheries, understanding the effects of regime shifts on these communities is essential to inform decisions that enhance ecological resilience and economic sustainability. © 2017 by the Ecological Society of America.

Shelters and Their Use by Fishes on Fringing Coral Reefs

PubMed Central

Ménard, Alexandre; Turgeon, Katrine; Roche, Dominique G.; Binning, Sandra A.; Kramer, Donald L.

2012-01-01

Coral reef fish density and species richness are often higher at sites with more structural complexity. This association may be due to greater availability of shelters, but surprisingly little is known about the size and density of shelters and their use by coral reef fishes. We quantified shelter availability and use by fishes for the first time on a Caribbean coral reef by counting all holes and overhangs with a minimum entrance diameter ≥3 cm in 30 quadrats (25 m2) on two fringing reefs in Barbados. Shelter size was highly variable, ranging from 42 cm3 to over 4,000,000 cm3, with many more small than large shelters. On average, there were 3.8 shelters m−2, with a median volume of 1,200 cm3 and a total volume of 52,000 cm3m−2. The number of fish per occupied shelter ranged from 1 to 35 individual fishes belonging to 66 species, with a median of 1. The proportion of shelters occupied and the number of occupants increased strongly with shelter size. Shelter density and total volume increased with substrate complexity, and this relationship varied among reef zones. The density of shelter-using fish was much more strongly predicted by shelter density and median size than by substrate complexity and increased linearly with shelter density, indicating that shelter availability is a limiting resource for some coral reef fishes. The results demonstrate the importance of large shelters for fish density and support the hypothesis that structural complexity is associated with fish abundance, at least in part, due to its association with shelter availability. This information can help identify critical habitat for coral reef fishes, predict the effects of reductions in structural complexity of natural reefs and improve the design of artificial reefs. PMID:22745664

Preliminary numerical simulation for shallow strata stability of coral reef in South China Sea

NASA Astrophysics Data System (ADS)

Tang, Qinqin; Zhan, Wenhuan; Zhang, Jinchang

2017-04-01

Coral reefs are the geologic material and special rock and soil, which live in shallow water of the tropic ocean and are formed through biological and geological action. Since infrastructure construction is being increasingly developed on coral reefs during recent years, it is necessary to evaluate the shallow strata stability of coral reefs in the South China Sea. The paper is to study the borehole profiles for shallow strata of coral reefs in the South China Sea, especially in the hydrodynamic marine environment?, and to establish a geological model for numerical simulation with Geo-Studio software. Five drilling holes show a six-layer shallow structure of South China Sea, including filling layer, mid-coarse sand, coral sand gravel, fine sand, limestone debris and reef limestone. The shallow coral reef profile next to lagoon is similar to "layers cake", in which the right side close to the sea is analogous to "block cake". The simulation results show that coral reef stability depends on wave loads and earthquake strength, as well as the physical properties of coral reefs themselves. The safety factor of the outer reef is greater than 10.0 in the static condition, indicating that outer reefs are less affected by the wave and earthquake. However, the safety factor next to lagoon is ranging from 0.1 to 4.9. The main reason for the variations that the strata of coral reefs close to the sea are thick. For example, the thickness of reef limestone is more than 10 m and equivalent to the block. When the thickness of inside strata is less than 10 m, they show weak engineering geological characteristics. These findings can provide useful information for coral reef constructions in future. This work was funded by National Basic Research Program of China (contract: 2013CB956104) and National Natural Science Foundation of China (contract: 41376063).

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

PubMed

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

2018-02-01

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

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.

Species richness of motile cryptofauna across a gradient of reef framework erosion

NASA Astrophysics Data System (ADS)

Enochs, I. C.; Manzello, D. P.

2012-09-01

Coral reef ecosystems contain exceptionally high concentrations of marine biodiversity, potentially encompassing millions of species. Similar to tropical rainforests and their insects, the majority of reef animal species are small and cryptic, living in the cracks and crevices of structural taxa (trees and corals). Although the cryptofauna make up the majority of a reef's metazoan biodiversity, we know little about their basic ecology. We sampled motile cryptofaunal communities from both live corals and dead carbonate reef framework across a gradient of increasing erosion on a reef in Pacific Panamá. A total of 289 Operational Taxonomic Units (OTUs) from six phyla were identified. We used species-accumulation models fitted to individual- and sample-based rarefaction curves, as well as seven nonparametric richness estimators to estimate species richness among the different framework types. All procedures predicted the same trends in species richness across the differing framework types. Estimated species richness was higher in dead framework (261-370 OTUs) than in live coral substrates (112-219 OTUs). Surprisingly, richness increased as framework structure was eroded: coral rubble contained the greatest number of species (227-320 OTUs) and the lowest estimated richness of 47-115 OTUs was found in the zone where the reef framework had the greatest vertical relief. This contradicts the paradigm that abundant live coral indicates the apex of reef diversity.

A geological perspective on the degradation and conservation of western Atlantic coral reefs.

PubMed

Kuffner, Ilsa B; Toth, Lauren T

2016-08-01

Continuing coral-reef degradation in the western Atlantic is resulting in loss of ecological and geologic functions of reefs. With the goal of assisting resource managers and stewards of reefs in setting and measuring progress toward realistic goals for coral-reef conservation and restoration, we examined reef degradation in this region from a geological perspective. The importance of ecosystem services provided by coral reefs-as breakwaters that dissipate wave energy and protect shorelines and as providers of habitat for innumerable species-cannot be overstated. However, the few coral species responsible for reef building in the western Atlantic during the last approximately 1.5 million years are not thriving in the 21st century. These species are highly sensitive to abrupt temperature extremes, prone to disease infection, and have low sexual reproductive potential. Their vulnerability and the low functional redundancy of branching corals have led to the low resilience of western Atlantic reef ecosystems. The decrease in live coral cover over the last 50 years highlights the need for study of relict (senescent) reefs, which, from the perspective of coastline protection and habitat structure, may be just as important to conserve as the living coral veneer. Research is needed to characterize the geological processes of bioerosion, reef cementation, and sediment transport as they relate to modern-day changes in reef elevation. For example, although parrotfish remove nuisance macroalgae, possibly promoting coral recruitment, they will not save Atlantic reefs from geological degradation. In fact, these fish are quickly nibbling away significant quantities of Holocene reef framework. The question of how different biota covering dead reefs affect framework resistance to biological and physical erosion needs to be addressed. Monitoring and managing reefs with respect to physical resilience, in addition to ecological resilience, could optimize the expenditure of resources in conserving Atlantic reefs and the services they provide. © 2016 The Authors. Conservation Biology published by Wiley Periodicals, Inc., on behalf of Society for Conservation Biology.

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.

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.

Understanding the murky history of the Coral Triangle: Miocene corals and reef habitats in East Kalimantan (Indonesia)

NASA Astrophysics Data System (ADS)

Santodomingo, Nadiezhda; Renema, Willem; Johnson, Kenneth G.

2016-09-01

Studies on ancient coral communities living in marginal conditions, including low light, high turbidity, extreme temperatures, or high nutrients, are important to understand the current structure of reefs and how they could potentially respond to global changes. The main goal of this study was to document the rich and well-preserved fossil coral fauna preserved in Miocene exposures of the Kutai Basin in East Kalimantan, Indonesia. Our collections include almost forty thousand specimens collected from 47 outcrops. Seventy-nine genera and 234 species have been identified. Three different coral assemblages were found corresponding to small patch reefs that developed under the influence of high siliciclastic inputs from the Mahakam Delta. Coral assemblages vary in richness, structure, and composition. Platy coral assemblages were common until the Serravallian (Middle Miocene), while branching coral assemblages became dominant in the Tortonian (Late Miocene). By the late Tortonian massive coral assemblages dominated, similar to modern-style coral framework. Our results suggest that challenging habitats, such as the Miocene turbid habitats of East Kalimantan, might have played an important role during the early diversification of the Coral Triangle by hosting a pool of resilient species more likely to survive the environmental changes that have affected this region since the Cenozoic. Further research that integrates fossil and recent turbid habitats may provide a glimpse into the dynamics and future of coral reefs as "typical" clear-water reefs continue to decline in most regions.

Changes in coral reef communities across a natural gradient in seawater pH

PubMed Central

Barkley, Hannah C.; Cohen, Anne L.; Golbuu, Yimnang; Starczak, Victoria R.; DeCarlo, Thomas M.; Shamberger, Kathryn E. F.

2015-01-01

Ocean acidification threatens the survival of coral reef ecosystems worldwide. The negative effects of ocean acidification observed in many laboratory experiments have been seen in studies of naturally low-pH reefs, with little evidence to date for adaptation. Recently, we reported initial data suggesting that low-pH coral communities of the Palau Rock Islands appear healthy despite the extreme conditions in which they live. Here, we build on that observation with a comprehensive statistical analysis of benthic communities across Palau’s natural acidification gradient. Our analysis revealed a shift in coral community composition but no impact of acidification on coral richness, coralline algae abundance, macroalgae cover, coral calcification, or skeletal density. However, coral bioerosion increased 11-fold as pH decreased from the barrier reefs to the Rock Island bays. Indeed, a comparison of the naturally low-pH coral reef systems studied so far revealed increased bioerosion to be the only consistent feature among them, as responses varied across other indices of ecosystem health. Our results imply that whereas community responses may vary, escalation of coral reef bioerosion and acceleration of a shift from net accreting to net eroding reef structures will likely be a global signature of ocean acidification. PMID:26601203

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 these two life history strategies may be better suited to cope with warmer oceans and thus may warrant protective status under climate change. PMID:27606598

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 these two life history strategies may be better suited to cope with warmer oceans and thus may warrant protective status under climate change.

A geological perspective on the degradation and conservation of western Atlantic coral reefs

USGS Publications Warehouse

Kuffner, Ilsa B.; Toth, Lauren T.

2016-01-01

Continuing coral-reef degradation in the western Atlantic is resulting in loss of ecological and geologic functions of reefs. With the goal of assisting resource managers and stewards of reefs in setting and measuring progress toward realistic goals for coral-reef conservation and restoration, we examined reef degradation in this region from a geological perspective. The importance of ecosystem services provided by coral reefs—as breakwaters that dissipate wave energy and protect shorelines and as providers of habitat for innumerable species—cannot be overstated. However, the few coral species responsible for reef building in the western Atlantic during the last approximately 1.5 million years are not thriving in the 21st century. These species are highly sensitive to abrupt temperature extremes, prone to disease infection, and have low sexual reproductive potential. Their vulnerability and the low functional redundancy of branching corals have led to the low resilience of western Atlantic reef ecosystems. The decrease in live coral cover over the last 50 years highlights the need for study of relict (senescent) reefs, which, from the perspective of coastline protection and habitat structure, may be just as important to conserve as the living coral veneer. Research is needed to characterize the geological processes of bioerosion, reef cementation, and sediment transport as they relate to modern-day changes in reef elevation. For example, although parrotfish remove nuisance macroalgae, possibly promoting coral recruitment, they will not save Atlantic reefs from geological degradation. In fact, these fish are quickly nibbling away significant quantities of Holocene reef framework. The question of how different biota covering dead reefs affect framework resistance to biological and physical erosion needs to be addressed. Monitoring and managing reefs with respect to physical resilience, in addition to ecological resilience, could optimize the expenditure of resources in conserving Atlantic reefs and the services they provide.

Structure of Caribbean coral reef communities across a large gradient of fish biomass.

PubMed

Newman, Marah J H; Paredes, Gustavo A; Sala, Enric; Jackson, Jeremy B C

2006-11-01

The collapse of Caribbean coral reefs has been attributed in part to historic overfishing, but whether fish assemblages can recover and how such recovery might affect the benthic reef community has not been tested across appropriate scales. We surveyed the biomass of reef communities across a range in fish abundance from 14 to 593 g m(-2), a gradient exceeding that of any previously reported for coral reefs. Increased fish biomass was correlated with an increased proportion of apex predators, which were abundant only inside large marine reserves. Increased herbivorous fish biomass was correlated with a decrease in fleshy algal biomass but corals have not yet recovered.

Patterns of population structure and dispersal in the long-lived "redwood" of the coral reef, the giant barrel sponge ( Xestospongia muta)

NASA Astrophysics Data System (ADS)

Richards, Vincent P.; Bernard, Andrea M.; Feldheim, Kevin A.; Shivji, Mahmood S.

2016-09-01

Sponges are one of the dominant fauna on Florida and Caribbean coral reefs, with species diversity often exceeding that of scleractinian corals. Despite the key role of sponges as structural components, habitat providers, and nutrient recyclers in reef ecosystems, their dispersal dynamics are little understood. We used ten microsatellite markers to study the population structure and dispersal patterns of a prominent reef species, the giant barrel sponge ( Xestospongia muta), the long-lived "redwood" of the reef, throughout Florida and the Caribbean. F-statistics, exact tests of population differentiation, and Bayesian multi-locus genotype analyses revealed high levels of overall genetic partitioning ( F ST = 0.12, P = 0.001) and grouped 363 individuals collected from the Bahamas, Honduras, US Virgin Islands, Key Largo (Florida), and the remainder of the Florida reef tract into at minimum five genetic clusters ( K = 5). Exact tests, however, revealed further differentiation, grouping sponges sampled from five locations across the Florida reef tract (~250 km) into three populations, suggesting a total of six genetic populations across the eight locations sampled. Assignment tests showed dispersal over ecological timescales to be limited to relatively short distances, as the only migration detected among populations was within the Florida reef tract. Consequently, populations of this major coral reef benthic constituent appear largely self-recruiting. A combination of levels of genetic differentiation, genetic distance, and assignment tests support the important role of the Caribbean and Florida currents in shaping patterns of contemporary and historical gene flow in this widespread coral reef species.

Critical research needs for identifying future changes in Gulf coral reef ecosystems.

PubMed

Feary, David A; Burt, John A; Bauman, Andrew G; Al Hazeem, Shaker; Abdel-Moati, Mohamed A; Al-Khalifa, Khalifa A; Anderson, Donald M; Amos, Carl; Baker, Andrew; Bartholomew, Aaron; Bento, Rita; Cavalcante, Geórgenes H; Chen, Chaolun Allen; Coles, Steve L; Dab, Koosha; Fowler, Ashley M; George, David; Grandcourt, Edwin; Hill, Ross; John, David M; Jones, David A; Keshavmurthy, Shashank; Mahmoud, Huda; Moradi Och Tapeh, Mahdi; Mostafavi, Pargol Ghavam; Naser, Humood; Pichon, Michel; Purkis, Sam; Riegl, Bernhard; Samimi-Namin, Kaveh; Sheppard, Charles; Vajed Samiei, Jahangir; Voolstra, Christian R; Wiedenmann, Joerg

2013-07-30

Expert opinion was assessed to identify current knowledge gaps in determining future changes in Arabian/Persian Gulf (thereafter 'Gulf') coral reefs. Thirty-one participants submitted 71 research questions that were peer-assessed in terms of scientific importance (i.e., filled a knowledge gap and was a research priority) and efficiency in resource use (i.e., was highly feasible and ecologically broad). Ten research questions, in six major research areas, were highly important for both understanding Gulf coral reef ecosystems and also an efficient use of limited research resources. These questions mirrored global evaluations of the importance of understanding and evaluating biodiversity, determining the potential impacts of climate change, the role of anthropogenic impacts in structuring coral reef communities, and economically evaluating coral reef communities. These questions provide guidance for future research on coral reef ecosystems within the Gulf, and enhance the potential for assessment and management of future changes in this globally significant region. Copyright © 2013 Elsevier Ltd. All rights reserved.

Plastic waste associated with disease on coral reefs.

PubMed

Lamb, Joleah B; Willis, Bette L; Fiorenza, Evan A; Couch, Courtney S; Howard, Robert; Rader, Douglas N; True, James D; Kelly, Lisa A; Ahmad, Awaludinnoer; Jompa, Jamaluddin; Harvell, C Drew

2018-01-26

Plastic waste can promote microbial colonization by pathogens implicated in outbreaks of disease in the ocean. We assessed the influence of plastic waste on disease risk in 124,000 reef-building corals from 159 reefs in the Asia-Pacific region. The likelihood of disease increases from 4% to 89% when corals are in contact with plastic. Structurally complex corals are eight times more likely to be affected by plastic, suggesting that microhabitats for reef-associated organisms and valuable fisheries will be disproportionately affected. Plastic levels on coral reefs correspond to estimates of terrestrial mismanaged plastic waste entering the ocean. We estimate that 11.1 billion plastic items are entangled on coral reefs across the Asia-Pacific and project this number to increase 40% by 2025. Plastic waste management is critical for reducing diseases that threaten ecosystem health and human livelihoods. Copyright © 2018, The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Critical research needs for identifying future changes in Gulf coral reef ecosystems

PubMed Central

Feary, David A.; Burt, John A.; Bauman, Andrew G.; Al Hazeem, Shaker; Abdel-Moati, Mohamed A.; Al-Khalifa, Khalifa A.; Anderson, Donald M.; Amos, Carl; Baker, Andrew; Bartholomew, Aaron; Bento, Rita; Cavalcante, Geórgenes H.; Chen, Chaolun Allen; Coles, Steve L.; Dab, Koosha; Fowler, Ashley M.; George, David; Grandcourt, Edwin; Hill, Ross; John, David M.; Jones, David A.; Keshavmurthy, Shashank; Mahmoud, Huda; Moradi Och Tapeh, Mahdi; Mostafavi, Pargol Ghavam; Naser, Humood; Pichon, Michel; Purkis, Sam; Riegl, Bernhard; Samimi-Namin, Kaveh; Sheppard, Charles; Vajed Samiei, Jahangir; Voolstra, Christian R.; Wiedenmann, Joerg

2014-01-01

Expert opinion was assessed to identify current knowledge gaps in determining future changes in Arabian/ Persian Gulf (thereafter ‘Gulf’) coral reefs. Thirty-one participants submitted 71 research questions that were peer-assessed in terms of scientific importance (i.e., filled a knowledge gap and was a research priority) and efficiency in resource use (i.e., was highly feasible and ecologically broad). Ten research questions, in six major research areas, were highly important for both understanding Gulf coral reef ecosystems and also an efficient use of limited research resources. These questions mirrored global evaluations of the importance of understanding and evaluating biodiversity, determining the potential impacts of climate change, the role of anthropogenic impacts in structuring coral reef communities, and economically evaluating coral reef communities. These questions provide guidance for future research on coral reef ecosystems within the Gulf, and enhance the potential for assessment and management of future changes in this globally significant region. PMID:23643407

Population structure of the hydrocoral Millepora platyphylla in habitats experiencing different flow regimes in Moorea, French Polynesia

PubMed Central

Mercière, Alexandre; Vermeij, Mark J. A.; Planes, Serge

2017-01-01

While the fire coral Millepora platyphylla is an important component of Indo-Pacific reefs, where it thrives in a wide range of environments, the ecological and biological processes driving its distribution and population structure are not well understood. Here, we quantified this species’ population structure in five habitats with contrasting hydrodynamic regimes in Moorea, French Polynesia; two in the fore reef: mid and upper slopes, and three in the lagoon: back, fringing and patch reefs. A total of 3651 colonies of fire corals were mapped and measured over 45,000 m2 of surveyed reef. Due to the species’ sensitivity to fragmentation in response to strong water movement, hydrodynamic conditions (e.g. waves, pass and lagoonal circulation) corresponded to marked differences in colony size distributions, morphology and recruitment dynamics among habitats. The size structure varied among reef habitats with higher proportions of larger colonies in calm nearshore reefs (fringing and patch reefs), while populations were dominated by smaller colonies in the exposed fore reefs. The highest densities of fire corals were recorded in fore reef habitats (0.12–0.20 n.m-2) where the proportion of recruits and juveniles was higher at mid slope populations (49.3%) than on the upper slope near where waves break (29.0%). In the latter habitat, most colonies grew as vertical sheets on encrusting bases making them more vulnerable to colony fragmentation, whereas fire corals were encrusting or massive in all other habitats. The lowest densities of M. platyphylla occurred in lagoonal habitats (0.02–0.04 n.m-2) characterized by a combination of low water movement and other physical and biological stressors. This study reports the first evidence of population structure of fire corals in two common reef environments and illustrates the importance of water flow in driving population dynamic processes of these reef-building species. PMID:28273119

Population structure of the hydrocoral Millepora platyphylla in habitats experiencing different flow regimes in Moorea, French Polynesia.

PubMed

Dubé, Caroline E; Mercière, Alexandre; Vermeij, Mark J A; Planes, Serge

2017-01-01

While the fire coral Millepora platyphylla is an important component of Indo-Pacific reefs, where it thrives in a wide range of environments, the ecological and biological processes driving its distribution and population structure are not well understood. Here, we quantified this species' population structure in five habitats with contrasting hydrodynamic regimes in Moorea, French Polynesia; two in the fore reef: mid and upper slopes, and three in the lagoon: back, fringing and patch reefs. A total of 3651 colonies of fire corals were mapped and measured over 45,000 m2 of surveyed reef. Due to the species' sensitivity to fragmentation in response to strong water movement, hydrodynamic conditions (e.g. waves, pass and lagoonal circulation) corresponded to marked differences in colony size distributions, morphology and recruitment dynamics among habitats. The size structure varied among reef habitats with higher proportions of larger colonies in calm nearshore reefs (fringing and patch reefs), while populations were dominated by smaller colonies in the exposed fore reefs. The highest densities of fire corals were recorded in fore reef habitats (0.12-0.20 n.m-2) where the proportion of recruits and juveniles was higher at mid slope populations (49.3%) than on the upper slope near where waves break (29.0%). In the latter habitat, most colonies grew as vertical sheets on encrusting bases making them more vulnerable to colony fragmentation, whereas fire corals were encrusting or massive in all other habitats. The lowest densities of M. platyphylla occurred in lagoonal habitats (0.02-0.04 n.m-2) characterized by a combination of low water movement and other physical and biological stressors. This study reports the first evidence of population structure of fire corals in two common reef environments and illustrates the importance of water flow in driving population dynamic processes of these reef-building species.

Impacts and recovery from severe tropical cyclone Yasi on the Great Barrier Reef.

PubMed

Beeden, Roger; Maynard, Jeffrey; Puotinen, Marjetta; Marshall, Paul; Dryden, Jen; Goldberg, Jeremy; Williams, Gareth

2015-01-01

Full recovery of coral reefs from tropical cyclone (TC) damage can take decades, making cyclones a major driver of habitat condition where they occur regularly. Since 1985, 44 TCs generated gale force winds (≥17 metres/second) within the Great Barrier Reef Marine Park (GBRMP). Of the hurricane strength TCs (≥H1-Saffir Simpson scale; ≥ category 3 Australian scale), TC Yasi (February, 2011) was the largest. In the weeks after TC Yasi crossed the GBRMP, participating researchers, managers and rangers assessed the extent and severity of reef damage via 841 Reef Health and Impact Surveys at 70 reefs. Records were scaled into five damage levels representing increasingly widespread colony-level damage (1, 2, 3) and reef structural damage (4, 5). Average damage severity was significantly affected by direction (north vs south of the cyclone track), reef shelf position (mid-shelf vs outer-shelf) and habitat type. More outer-shelf reefs suffered structural damage than mid-shelf reefs within 150 km of the track. Structural damage spanned a greater latitudinal range for mid-shelf reefs than outer-shelf reefs (400 vs 300 km). Structural damage was patchily distributed at all distances, but more so as distance from the track increased. Damage extended much further from the track than during other recent intense cyclones that had smaller circulation sizes. Just over 15% (3,834 km2) of the total reef area of the GBRMP is estimated to have sustained some level of coral damage, with ~4% (949 km2) sustaining a degree of structural damage. TC Yasi likely caused the greatest loss of coral cover on the GBR in a 24-hour period since 1985. Severely impacted reefs have started to recover; coral cover increased an average of 4% between 2011 and 2013 at re-surveyed reefs. The in situ assessment of impacts described here is the largest in scale ever conducted on the Great Barrier Reef following a reef health disturbance.

Impacts and Recovery from Severe Tropical Cyclone Yasi on the Great Barrier Reef

PubMed Central

Beeden, Roger; Maynard, Jeffrey; Puotinen, Marjetta; Marshall, Paul; Dryden, Jen; Goldberg, Jeremy; Williams, Gareth

2015-01-01

Full recovery of coral reefs from tropical cyclone (TC) damage can take decades, making cyclones a major driver of habitat condition where they occur regularly. Since 1985, 44 TCs generated gale force winds (≥17 metres/second) within the Great Barrier Reef Marine Park (GBRMP). Of the hurricane strength TCs (≥H1—Saffir Simpson scale; ≥ category 3 Australian scale), TC Yasi (February, 2011) was the largest. In the weeks after TC Yasi crossed the GBRMP, participating researchers, managers and rangers assessed the extent and severity of reef damage via 841 Reef Health and Impact Surveys at 70 reefs. Records were scaled into five damage levels representing increasingly widespread colony-level damage (1, 2, 3) and reef structural damage (4, 5). Average damage severity was significantly affected by direction (north vs south of the cyclone track), reef shelf position (mid-shelf vs outer-shelf) and habitat type. More outer-shelf reefs suffered structural damage than mid-shelf reefs within 150 km of the track. Structural damage spanned a greater latitudinal range for mid-shelf reefs than outer-shelf reefs (400 vs 300 km). Structural damage was patchily distributed at all distances, but more so as distance from the track increased. Damage extended much further from the track than during other recent intense cyclones that had smaller circulation sizes. Just over 15% (3,834 km2) of the total reef area of the GBRMP is estimated to have sustained some level of coral damage, with ~4% (949 km2) sustaining a degree of structural damage. TC Yasi likely caused the greatest loss of coral cover on the GBR in a 24-hour period since 1985. Severely impacted reefs have started to recover; coral cover increased an average of 4% between 2011 and 2013 at re-surveyed reefs. The in situ assessment of impacts described here is the largest in scale ever conducted on the Great Barrier Reef following a reef health disturbance. PMID:25874718

Flattening of Caribbean coral reefs: region-wide declines in architectural complexity

PubMed Central

Alvarez-Filip, Lorenzo; Dulvy, Nicholas K.; Gill, Jennifer A.; Côté, Isabelle M.; Watkinson, Andrew R.

2009-01-01

Coral reefs are rich in biodiversity, in large part because their highly complex architecture provides shelter and resources for a wide range of organisms. Recent rapid declines in hard coral cover have occurred across the Caribbean region, but the concomitant consequences for reef architecture have not been quantified on a large scale to date. We provide, to our knowledge, the first region-wide analysis of changes in reef architectural complexity, using nearly 500 surveys across 200 reefs, between 1969 and 2008. The architectural complexity of Caribbean reefs has declined nonlinearly with the near disappearance of the most complex reefs over the last 40 years. The flattening of Caribbean reefs was apparent by the early 1980s, followed by a period of stasis between 1985 and 1998 and then a resumption of the decline in complexity to the present. Rates of loss are similar on shallow (<6 m), mid-water (6–20 m) and deep (>20 m) reefs and are consistent across all five subregions. The temporal pattern of declining architecture coincides with key events in recent Caribbean ecological history: the loss of structurally complex Acropora corals, the mass mortality of the grazing urchin Diadema antillarum and the 1998 El Nino Southern Oscillation-induced worldwide coral bleaching event. The consistently low estimates of current architectural complexity suggest regional-scale degradation and homogenization of reef structure. The widespread loss of architectural complexity is likely to have serious consequences for reef biodiversity, ecosystem functioning and associated environmental services. PMID:19515663

Extinction rate, historical population structure and ecological role of the Caribbean monk seal

PubMed Central

McClenachan, Loren; Cooper, Andrew B

2008-01-01

The productivity and biomass of pristine coral reef ecosystems is poorly understood, particularly in the Caribbean where communities have been impacted by overfishing and multiple other stressors over centuries. Using historical data on the spatial distribution and abundance of the extinct Caribbean monk seal (Monachus tropicalis), this study reconstructs the population size, structure and ecological role of this once common predator within coral reef communities, and provides evidence that historical reefs supported biomasses of fishes and invertebrates up to six times greater than those found on typical modern Caribbean reefs. An estimated 233 000–338 000 monk seals were distributed among 13 colonies across the Caribbean. The biomass of reef fishes and invertebrates required to support historical seal populations was 732–1018 g m−2 of reefs, which exceeds that found on any Caribbean reef today and is comparable with those measured in remote Pacific reefs. Quantitative estimates of historically dense monk seal colonies and their consumption rates on pristine reefs provide concrete data on the magnitude of decline in animal biomass on Caribbean coral reefs. Realistic reconstruction of these past ecosystems is critical to understanding the profound and long-lasting effect of human hunting on the functioning of coral reef ecosystems. PMID:18348965

Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems.

PubMed

Graham, Nicholas A J; McClanahan, Tim R; MacNeil, M Aaron; Wilson, Shaun K; Polunin, Nicholas V C; Jennings, Simon; Chabanet, Pascale; Clark, Susan; Spalding, Mark D; Letourneur, Yves; Bigot, Lionel; Galzin, René; Ohman, Marcus C; Garpe, Kajsa C; Edwards, Alasdair J; Sheppard, Charles R C

2008-08-27

Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the 1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure, diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales, with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance. This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should be integrated into existing management frameworks and combined with policies to improve system-wide resilience to climate variation and change.

A New Perspective: Assessing the Spatial Distribution of Coral Bleaching with Unmanned Low Altitude Remote Sensing Systems

NASA Astrophysics Data System (ADS)

Levy, J.; Franklin, E. C.; Hunter, C. L.

2016-12-01

Coral reefs are biodiversity hotspots that are vital to the function of global economic and biological processes. Coral bleaching is a significant contributor to the global decline of reefs and can impact an expansive reef area over short timescales. In order to understand the dynamics of coral bleaching and how these stress events impact reef ecosystems, it is important to conduct rapid bleaching surveys at functionally important spatial scales. Due to the inherent heterogeneity, size, and in some cases, remoteness of coral reefs, it is difficult to routinely monitor coral bleaching dynamics before, during, and after bleaching. Additionally, current in situ survey methods only collect snippets of discrete reef data over small reef areas, which are unable to accurately represent the reef as a whole. We present a new technique using small unmanned aerial systems (sUAS) as cost effective, efficient monitoring tools that target small to intermediate-scale reef dynamics to understand the spatial distribution of bleached coral colonies during the 2015 bleaching event on patch reefs in Kaneohe Bay, Oahu. Overlapping low altitude aerial images were collected at four reefs during the bleaching period and processed using Structure-from-Motion techniques to produce georeferenced and spatially accurate orthomosaics of complete reef areas. Mosaics were analyzed using manual and heuristic neural network classification schemes to identify comprehensive populations of bleached and live coral on each patch reef. We found that bleached colonies had random and clumped distributions on patch reefs in Kaneohe Bay depending on local environmental conditions. Our work demonstrates that sUAS provide a low cost, efficient platform that can rapidly and repeatedly collect high-resolution imagery (1 cm/pixel) and map large areas of shallow reef ecosystems (5 hectares). This study proves the feasibility of utilizing sUAS as a tool to collect spatially rich reef data that will provide reef scientists a new perspective on meso-scale coral reef dynamics. We envision that similar low altitude aerial surveys will be incorporated as a standard component of shallow-water reef studies, especially on reefs too dangerous or remote for in situ surveys.

Benthic community structure on coral reefs exposed to intensive recreational snorkeling.

PubMed

Renfro, Bobbie; Chadwick, Nanette E

2017-01-01

Chronic anthropogenic disturbances on coral reefs in the form of overfishing and pollution can shift benthic community composition away from stony corals and toward macroalgae. The use of reefs for recreational snorkeling and diving potentially can lead to similar ecological impacts if not well-managed, but impacts of snorkeling on benthic organisms are not well understood. We quantified variation in benthic community structure along a gradient of snorkeling frequency in an intensively-visited portion of the Mesoamerican Barrier Reef. We determined rates of snorkeling in 6 water sections and rates of beach visitation in 4 adjacent land sections at Akumal Bay, Mexico. For each in-water section at 1-3 m depth, we also assessed the percent cover of benthic organisms including taxa of stony corals and macroalgae. Rates of recreational snorkeling varied from low in the southwestern to very high (>1000 snorkelers d-1) in the northeastern sections of the bay. Stony coral cover decreased and macroalgal cover increased significantly with levels of snorkeling, while trends varied among taxa for other organisms such as gorgonians, fire corals, and sea urchins. We conclude that benthic organisms appear to exhibit taxon-specific variation with levels of recreational snorkeling. To prevent further degradation, we recommend limitation of snorkeler visitation rates, coupled with visitor education and in-water guides to reduce reef-damaging behaviors by snorkelers in high-use areas. These types of management activities, integrated with reef monitoring and subsequent readjustment of management, have the potential to reverse the damage potentially inflicted on coral reefs by the expansion of reef-based recreational snorkeling.

Benthic community structure on coral reefs exposed to intensive recreational snorkeling

PubMed Central

Renfro, Bobbie

2017-01-01

Chronic anthropogenic disturbances on coral reefs in the form of overfishing and pollution can shift benthic community composition away from stony corals and toward macroalgae. The use of reefs for recreational snorkeling and diving potentially can lead to similar ecological impacts if not well-managed, but impacts of snorkeling on benthic organisms are not well understood. We quantified variation in benthic community structure along a gradient of snorkeling frequency in an intensively-visited portion of the Mesoamerican Barrier Reef. We determined rates of snorkeling in 6 water sections and rates of beach visitation in 4 adjacent land sections at Akumal Bay, Mexico. For each in-water section at 1–3 m depth, we also assessed the percent cover of benthic organisms including taxa of stony corals and macroalgae. Rates of recreational snorkeling varied from low in the southwestern to very high (>1000 snorkelers d-1) in the northeastern sections of the bay. Stony coral cover decreased and macroalgal cover increased significantly with levels of snorkeling, while trends varied among taxa for other organisms such as gorgonians, fire corals, and sea urchins. We conclude that benthic organisms appear to exhibit taxon-specific variation with levels of recreational snorkeling. To prevent further degradation, we recommend limitation of snorkeler visitation rates, coupled with visitor education and in-water guides to reduce reef-damaging behaviors by snorkelers in high-use areas. These types of management activities, integrated with reef monitoring and subsequent readjustment of management, have the potential to reverse the damage potentially inflicted on coral reefs by the expansion of reef-based recreational snorkeling. PMID:28873449

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

NASA Astrophysics Data System (ADS)

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

2013-09-01

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

Controls on coral-ground development along the northern Mesoamerican Reef tract.

PubMed

Rodríguez-Martínez, Rosa E; Jordán-Garza, Adán G; Maldonado, Miguel A; Blanchon, Paul

2011-01-01

Coral-grounds are reef communities that colonize rocky substratum but do not form framework or three-dimensional reef structures. To investigate why, we used video transects and underwater photography to determine the composition, structure and status of a coral-ground community located on the edge of a rocky terrace in front of a tourist park, Xcaret, in the northern Mesoamerican Reef tract, Mexico. The community has a relatively low coral, gorgonian and sponge cover (<10%) and high algal cover (>40%). We recorded 23 species of Scleractinia, 14 species of Gorgonacea and 30 species of Porifera. The coral community is diverse but lacks large coral colonies, being dominated instead by small, sediment-tolerant, and brooding species. In these small colonies, the abundance of potentially lethal interactions and partial mortality is high but decreases when colonies are larger than 40 cm. Such characteristics are consistent with an environment control whereby storm waves periodically remove larger colonies and elevate sediment flux. The community only survives these storm conditions due to its slope-break location, which ensures lack of burial and continued local recruitment. A comparison with similar coral-ground communities in adjacent areas suggests that the narrow width of the rock terrace hinders sediment stabilization, thereby ensuring that communities cannot escape bottom effects and develop into three-dimensional reef structures on geological time scales.

The implications of recurrent disturbances within the world's hottest coral reef.

PubMed

Bento, Rita; Hoey, Andrew S; Bauman, Andrew G; Feary, David A; Burt, John A

2016-04-30

Determining how coral ecosystems are structured within extreme environments may provide insights into how coral reefs are impacted by future climate change. Benthic community structure was examined within the Persian Gulf, and adjacent Musandam and northern Oman regions across a 3-year period (2008-2011) in which all regions were exposed to major disturbances. Although there was evidence of temporal switching in coral composition within regions, communities predominantly reflected local environmental conditions and the disturbance history of each region. Gulf reefs showed little change in coral composition, being dominated by stress-tolerant Faviidae and Poritidae across the 3 years. In comparison, Musandam and Oman coral communities were comprised of stress-sensitive Acroporidae and Pocilloporidae; Oman communities showed substantial declines in such taxa and increased cover of stress-tolerant communities. Our results suggest that coral communities may persist within an increasingly disturbed future environment, albeit in a much more structurally simple configuration. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2018-06-01

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

The effects of top-down versus bottom-up control on benthic coral reef community structure.

PubMed

Smith, Jennifer E; Hunter, Cynthia L; Smith, Celia M

2010-06-01

While climate change and associated increases in sea surface temperature and ocean acidification, are among the most important global stressors to coral reefs, overfishing and nutrient pollution are among the most significant local threats. Here we examined the independent and interactive effects of reduced grazing pressure and nutrient enrichment using settlement tiles on a coral-dominated reef via long-term manipulative experimentation. We found that unique assemblages developed in each treatment combination confirming that both nutrients and herbivores are important drivers of reef community structure. When herbivores were removed, fleshy algae dominated, while crustose coralline algae (CCA) and coral were more abundant when herbivores were present. The effects of fertilization varied depending on herbivore treatment; without herbivores fleshy algae increased in abundance and with herbivores, CCA increased. Coral recruits only persisted in treatments exposed to grazers. Herbivore removal resulted in rapid changes in community structure while there was a lag in response to fertilization. Lastly, re-exposure of communities to natural herbivore populations caused reversals in benthic community trajectories but the effects of fertilization remained for at least 2 months. These results suggest that increasing herbivore populations on degraded reefs may be an effective strategy for restoring ecosystem structure and function and in reversing coral-algal phase-shifts but that this strategy may be most effective in the absence of other confounding disturbances such as nutrient pollution.

A cross-ocean comparison of responses to settlement cues in reef-building corals

PubMed Central

Meyer, Eli; Guermond, Sarah M.; Matz, Mikhail V.

2014-01-01

Caribbean coral reefs have deteriorated substantially over the past 30 years, which is broadly attributable to the effects of global climate change. In the same time, Indo-Pacific reefs maintain higher coral cover and typically recover rapidly after disturbances. This difference in reef resilience is largely due to much higher coral recruitment rates in the Pacific. We hypothesized that the lack of Caribbean recruitment might be explained by diminishing quality of settlement cues and/or impaired sensitivity of Caribbean coral larvae to those cues, relative to the Pacific. To evaluate this hypothesis, we assembled a collection of bulk samples of reef encrusting communities, mostly consisting of crustose coralline algae (CCA), from various reefs around the world and tested them as settlement cues for several coral species originating from different ocean provinces. Cue samples were meta-barcoded to evaluate their taxonomic diversity. We observed no systematic differences either in cue potency or in strength of larval responses depending on the ocean province, and no preference of coral larvae towards cues from the same ocean. Instead, we detected significant differences in cue preferences among coral species, even for corals originating from the same reef. We conclude that the region-wide disruption of the settlement process is unlikely to be the major cause of Caribbean reef loss. However, due to their high sensitivity to the effects of climate change, shifts in the composition of CCA-associated communities, combined with pronounced differences in cue preferences among coral species, could substantially influence future coral community structure. PMID:24765568

Mangrove habitats provide refuge from climate change for reef-building corals

NASA Astrophysics Data System (ADS)

Yates, K. K.; Rogers, C. S.; Herlan, J. J.; Brooks, G. R.; Smiley, N. A.; Larson, R. A.

2014-03-01

Risk analyses indicate that more than 90% of the world's reefs will be threatened by climate change and local anthropogenic impacts by the year 2030 under "business as usual" climate scenarios. Increasing temperatures and solar radiation cause coral bleaching that has resulted in extensive coral mortality. Increasing carbon dioxide reduces seawater pH, slows coral growth, and may cause loss of reef structure. Management strategies include establishment of marine protected areas with environmental conditions that promote reef resiliency. However, few resilient reefs have been identified, and resiliency factors are poorly defined. Here we characterize the first natural, non-reef, coral refuge from thermal stress and ocean acidification and identify resiliency factors for mangrove-coral habitats. We measured diurnal and seasonal variations in temperature, salinity, photosynthetically active radiation (PAR), and seawater chemistry; characterized substrate parameters; and examined water circulation patterns in mangrove communities where scleractinian corals are growing attached to and under mangrove prop roots in Hurricane Hole, St. John, US Virgin Islands. Additionally, we inventoried the coral species and quantified incidences of coral bleaching, mortality and recovery for two major reef-building corals, Colpophyllia natans and Diploria labyrinthiformis, growing in mangrove shaded and exposed (unshaded) areas. At least 33 species of scleractinian corals were growing in association with mangroves. Corals were thriving in low-light (more than 70% attenuation of incident PAR) from mangrove shading and at higher temperatures than nearby reef tract corals. A higher percentage of C. natans colonies was living shaded by mangroves, and no shaded colonies bleached. Fewer D. labyrinthiformis colonies were shaded by mangroves, however more unshaded colonies bleached. A combination of substrate and habitat heterogeniety, proximity of different habitat types, hydrographic conditions, and biological influences on seawater chemistry generate chemical conditions that buffer against ocean acidification. This previously undocumented refuge for corals provides evidence for adaptation of coastal organisms and ecosystem transition due to recent climate change. Identifying and protecting other natural, non-reef coral refuges is critical for sustaining corals and other reef species into the future.

Carbon dioxide addition to coral reef waters suppresses net community calcification.

PubMed

Albright, Rebecca; Takeshita, Yuichiro; Koweek, David A; Ninokawa, Aaron; Wolfe, Kennedy; Rivlin, Tanya; Nebuchina, Yana; Young, Jordan; Caldeira, Ken

2018-03-22

Coral reefs feed millions of people worldwide, provide coastal protection and generate billions of dollars annually in tourism revenue. The underlying architecture of a reef is a biogenic carbonate structure that accretes over many years of active biomineralization by calcifying organisms, including corals and algae. Ocean acidification poses a chronic threat to coral reefs by reducing the saturation state of the aragonite mineral of which coral skeletons are primarily composed, and lowering the concentration of carbonate ions required to maintain the carbonate reef. Reduced calcification, coupled with increased bioerosion and dissolution, may drive reefs into a state of net loss this century. Our ability to predict changes in ecosystem function and associated services ultimately hinges on our understanding of community- and ecosystem-scale responses. Past research has primarily focused on the responses of individual species rather than evaluating more complex, community-level responses. Here we use an in situ carbon dioxide enrichment experiment to quantify the net calcification response of a coral reef flat to acidification. We present an estimate of community-scale calcification sensitivity to ocean acidification that is, to our knowledge, the first to be based on a controlled experiment in the natural environment. This estimate provides evidence that near-future reductions in the aragonite saturation state will compromise the ecosystem function of coral reefs.

Carbon dioxide addition to coral reef waters suppresses net community calcification

NASA Astrophysics Data System (ADS)

Albright, Rebecca; Takeshita, Yuichiro; Koweek, David A.; Ninokawa, Aaron; Wolfe, Kennedy; Rivlin, Tanya; Nebuchina, Yana; Young, Jordan; Caldeira, Ken

2018-03-01

Coral reefs feed millions of people worldwide, provide coastal protection and generate billions of dollars annually in tourism revenue. The underlying architecture of a reef is a biogenic carbonate structure that accretes over many years of active biomineralization by calcifying organisms, including corals and algae. Ocean acidification poses a chronic threat to coral reefs by reducing the saturation state of the aragonite mineral of which coral skeletons are primarily composed, and lowering the concentration of carbonate ions required to maintain the carbonate reef. Reduced calcification, coupled with increased bioerosion and dissolution, may drive reefs into a state of net loss this century. Our ability to predict changes in ecosystem function and associated services ultimately hinges on our understanding of community- and ecosystem-scale responses. Past research has primarily focused on the responses of individual species rather than evaluating more complex, community-level responses. Here we use an in situ carbon dioxide enrichment experiment to quantify the net calcification response of a coral reef flat to acidification. We present an estimate of community-scale calcification sensitivity to ocean acidification that is, to our knowledge, the first to be based on a controlled experiment in the natural environment. This estimate provides evidence that near-future reductions in the aragonite saturation state will compromise the ecosystem function of coral reefs.

Global microbialization of coral reefs.

PubMed

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

2016-04-25

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

Fish-derived nutrient hotspots shape coral reef benthic communities.

PubMed

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

2015-12-01

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

Benthic habitat and fish assemblage structure from shallow to mesophotic depths in a storm-impacted marine protected area

NASA Astrophysics Data System (ADS)

Abesamis, Rene A.; Langlois, Tim; Birt, Matthew; Thillainath, Emma; Bucol, Abner A.; Arceo, Hazel O.; Russ, Garry R.

2018-03-01

Baseline ecological studies of mesophotic coral ecosystems are lacking in the equatorial Indo-West Pacific region where coral reefs are highly threatened by anthropogenic and climate-induced disturbances. Here, we used baited remote underwater video to describe benthic habitat and fish assemblage structure from 10 to 80 m depth at Apo Island, a well-managed marine protected area in the Philippines. We conducted surveys 2 yr after two storms (in 2011 and 2012) caused severe damage to shallow coral communities within the no-take marine reserve (NTMR) of Apo Island, which led to declines in fish populations that had built up over three decades. We found that hard coral cover was restricted to < 40 m deep in the storm-impacted NTMR and a nearby fished area not impacted by storms. Benthic cover at mesophotic depths (> 30 m) was dominated by sand/rubble and rock (dead coral) with low cover of soft corals, sponges and macroalgae. Storm damage appeared to have reached the deepest limit of the fringing reef (40 m) and reduced variability in benthic structure within the NTMR. Species richness and/or abundance of most trophic groups of fish declined with increasing depth regardless of storm damage. There were differences in taxonomic and trophic structure and degree of targeting by fisheries between shallow and mesophotic fish assemblages. Threatened shark species and a fish species previously unreported in the Philippines were recorded at mesophotic depths. Our findings provide a first glimpse of the benthic and fish assemblage structure of Philippine coral reef ecosystems across a wide depth gradient. This work also underscores how a combination of limited coral reef development at mesophotic depths close to shallow reefs and severe habitat loss caused by storms would result in minimal depth refuge for reef fish populations.

Biodiversity and community composition of sediment macrofauna associated with deep-sea Lophelia pertusa habitats in the Gulf of Mexico

USGS Publications Warehouse

Demopoulos, Amanda W.J.; Bourque, Jill R.; Frometa, Janessy

2014-01-01

Scleractinian corals create three-dimensional reefs that provide sheltered refuges, facilitate sediment accumulation, and enhance colonization of encrusting fauna. While heterogeneous coral habitats can harbor high levels of biodiversity, their effect on the community composition within nearby sediments remains unclear, particularly in the deep sea. Sediment macrofauna from deep-sea coral habitats (Lophelia pertusa) and non-coral, background sediments were examined at three sites in the northern Gulf of Mexico (VK826, VK906, MC751, 350–500 m depth) to determine whether macrofaunal abundance, diversity, and community composition near corals differed from background soft-sediments. Macrofaunal densities ranged from 26 to 125 individuals 32 cm−2 and were significantly greater near coral versus background sediments only at VK826. Of the 86 benthic invertebrate taxa identified, 16 were exclusive to near-coral habitats, while 14 were found only in background sediments. Diversity (Fisher’s α) and evenness were significantly higher within near-coral sediments only at MC751 while taxon richness was similar among all habitats. Community composition was significantly different both between near-coral and background sediments and among the three primary sites. Polychaetes numerically dominated all samples, accounting for up to 70% of the total individuals near coral, whereas peracarid crustaceans were proportionally more abundant in background sediments (18%) than in those near coral (10%). The reef effect differed among sites, with community patterns potentially influenced by the size of reef habitat. Taxon turnover occurred with distance from the reef, suggesting that reef extent may represent an important factor in structuring sediment communities near L. pertusa. Polychaete communities in both habitats differed from other Gulf of Mexico (GOM) soft sediments based on data from previous studies, and we hypothesize that local environmental conditions found near L. pertusa may influence the macrofaunal community structure beyond the edges of the reef. This study represents the first assessment of L. pertusa-associated sediment communities in the GOM and provides baseline data that can help define the role of transition zones, from deep reefs to soft sediments, in shaping macrofaunal community structure and maintaining biodiversity; this information can help guide future conservation and management activities.

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 these metrics; identify opportunities for immediate collaborations using existing resources that can serve to reduce the identified gaps; and help to clarify expectations for ocean acidification monitoring.

Wave energy and swimming performance shape coral reef fish assemblages

PubMed Central

Fulton, C.J; Bellwood, D.R; Wainwright, P.C

2005-01-01

Physical factors often have an overriding influence on the distribution patterns of organisms, and can ultimately shape the long-term structure of communities. Although distribution patterns in sessile marine organisms have frequently been attributed to functional characteristics interacting with wave-induced water motion, similar evidence for mobile organisms is lacking. Links between fin morphology and swimming performance were examined in three diverse coral reef fish families from two major evolutionary lineages. Among-habitat variation in morphology and performance was directly compared with quantitative values of wave-induced water motion from seven coral reef habitats of different depth and wave exposure on the Great Barrier Reef. Fin morphology was strongly correlated with both field and experimental swimming speeds in all three families. The range of observed swimming speeds coincided closely with the magnitude of water velocities commonly found on coral reefs. Distribution patterns in all three families displayed highly congruent relationships between fin morphology and wave-induced water motion. Our findings indicate a general functional relationship between fin morphology and swimming performance in labriform-swimming fishes, and provide quantitative evidence that wave energy may directly influence the assemblage structure of coral reef fishes through interactions with morphology and swimming performance. PMID:15888415

Climate change impacts on coral reefs: synergies with local effects, possibilities for acclimation, and management implications.

PubMed

Ateweberhan, Mebrahtu; Feary, David A; Keshavmurthy, Shashank; Chen, Allen; Schleyer, Michael H; Sheppard, Charles R C

2013-09-30

Most reviews concerning the impact of climate change on coral reefs discuss independent effects of warming or ocean acidification. However, the interactions between these, and between these and direct local stressors are less well addressed. This review underlines that coral bleaching, acidification, and diseases are expected to interact synergistically, and will negatively influence survival, growth, reproduction, larval development, settlement, and post-settlement development of corals. Interactions with local stress factors such as pollution, sedimentation, and overfishing are further expected to compound effects of climate change. Reduced coral cover and species composition following coral bleaching events affect coral reef fish community structure, with variable outcomes depending on their habitat dependence and trophic specialisation. Ocean acidification itself impacts fish mainly indirectly through disruption of predation- and habitat-associated behavior changes. Zooxanthellate octocorals on reefs are often overlooked but are substantial occupiers of space; these also are highly susceptible to bleaching but because they tend to be more heterotrophic, climate change impacts mainly manifest in terms of changes in species composition and population structure. Non-calcifying macroalgae are expected to respond positively to ocean acidification and promote microbe-induced coral mortality via the release of dissolved compounds, thus intensifying phase-shifts from coral to macroalgal domination. Adaptation of corals to these consequences of CO2 rise through increased tolerance of corals and successful mutualistic associations between corals and zooxanthellae is likely to be insufficient to match the rate and frequency of the projected changes. Impacts are interactive and magnified, and because there is a limited capacity for corals to adapt to climate change, global targets of carbon emission reductions are insufficient for coral reefs, so lower targets should be pursued. Alleviation of most local stress factors such as nutrient discharges, sedimentation, and overfishing is also imperative if sufficient overall resilience of reefs to climate change is to be achieved. Copyright © 2013 Elsevier Ltd. All rights reserved.

Baseline assessments for coral reef community structure and demographics on West Maui

USGS Publications Warehouse

Vargas-Angel, Bernardo; White, Darla; Storlazzi, Curt; Callender, Tova; Maurin, Paulo

2017-01-01

The coastal and upslope terrains of West Maui have had a long history of impacts owing to more than a century of human activities. Resource extraction, agriculture, as well as residential and resort development have caused land-based pollution that impairs water quality and adversely impact the adjacent marine ecosystem. Today, West Maui’s coral reefs are chronically impacted by the effects of land-based pollution, mainly sedimentation and nutrients, with documented losses of 30 – 75% in coral cover over the last 20 years. Nonetheless, despite their current status and levels of environmental impact, these coral reef communities represent a key local resource and a counterpoint to the overall low coral reef development levels both island- and state-wide. This is of high relevance because the occurrence of coral-rich assemblages and accreted reef complexes statewide is sparse. Only limited segments along the coastlines of Maui, Hawai‘i, Lana‘i, Moloka‘i, and Kaho‘olawe, harbor mature, fringing coral reefs; and unfortunately, many of them are seriously threatened by terrestrial runoff. This report describes the results of baseline assessment surveys of coral reef benthic structure, coral community demographics, and coral condition. These surveys are intended to provide benchmarks for continued monitoring efforts and provide a gauge for comparing and evaluating the effectiveness of management actions to reduce land-based sources of pollution in priority watersheds on West Maui. Within this context, 12 permanent, long-term monitoring sites were strategically established adjacent to the 7 primary stream drainages (Wahikuli, Honokōwai, Mahinahina, Kahana/Ka‘opala, Honokeana, Honokahua, and Honolua) within the five priority watersheds (Wahikuli, Honokōwai, Kahana, Honokahua, and Honolua). Herein, benthic cover and composition, coral demographics, and coral condition of the monitoring sites are described and contrasted in the “Benthic Characterization” and “Synthesis and Discussion” sections of this report. The baseline assessments revealed that although some areas harbor prominent coral reef structures with high live coral cover and multispecies assemblages, others are characterized by sediment-impacted corals in impoverished and species-poor communities. Mean coral cover varied widely, from 49% at Wahikuli-shallow to 4.6% at Mahinahina-shallow. Similarly, coralline algal cover averaged 12.7% at Ka‘opala and Honokeana-north, but was altogether absent at the Mahinahina sites. Macroalgae was a minor component of the benthos across all study sites, representing only up to 2.3% at Mahinahina-south, while turf algae varied considerably, from 41% at Honokeana-north to 84% at the Honokahua site. Consequently, the Benthic Substrate Ratio (BSR) also varied considerably region wide, with the highest values (≥ 1), suggesting a healthier reef condition reported for the Wahikuli, Honokeana, and Honokōwai sites; and the lowest (≤ 0.5), suggesting impairment in structure and function, recorded at the Honolua and Honokahua sites. Adult colony densities were the highest at the Wahikuli (27 col/m2) but lowest at the Ka‘opala (7 col/m2 ) site. And, colony partial mortality peaked at the Ka‘opala (33%) and was the lowest at the Honokeana Bay (12%). Moreover, in-situ and derived estimates of water turbidity and sediment loading revealed that the Ka‘opala and Wahikuli stream sites ranked the highest for turbidity, whereas the Honokōwai and Ka‘opala sites ranked highest for sediment loading. Chronic and episodic terrestrial sediment stress has resulted in coral reef community demise, clearly illustrated at the Honolua, Honokahua, and Ka‘opala sites, where coral benthic cover and colony abundances ranked the lowest and levels of turf algae ranked among the highest. Left unattended, land-based pollution impacts will continue to negatively affect the coral reef communities of West Maui. And, under the current turbidity and sediment loading conditions, the coral-rich habitats in the Wahikuli and Honōkowai Watersheds are probably at greatest risk, given they harbor the most prominent and well-developed reefs in the region, characterized by the highest coral cover, colony densities, and structural complexity.

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

Persistence of coral assemblages at East and West Flower Garden Banks, Gulf of Mexico

NASA Astrophysics Data System (ADS)

Johnston, Michelle A.; Embesi, John A.; Eckert, Ryan J.; Nuttall, Marissa F.; Hickerson, Emma L.; Schmahl, George P.

2016-09-01

Since 1989 a federally supported long-term coral reef monitoring program has focused on two study sites atop East and West Flower Garden Banks in the northwestern Gulf of Mexico. We examined 25 yr of benthic cover data to provide a multi-decadal baseline and trend analysis of the community structure for this coral reef system. Despite global coral reef decline in recent decades, mean coral cover at East and West Flower Garden Banks was above 50% for the combined 25 yr of continuous monitoring, and represented a stable coral community. However, mean macroalgal cover increased significantly between 1998 and 1999, rising from approximately 3 to 20%, and reaching a maximum above 30% in 2012. In contrast to many other shallow water reefs in the Caribbean region, increases in mean macroalgal cover have not been concomitant with coral cover decline at the Flower Garden Banks.

Attenuating effects of ecosystem management on coral reefs.

PubMed

Steneck, Robert S; Mumby, Peter J; MacDonald, Chancey; Rasher, Douglas B; Stoyle, George

2018-05-01

Managing diverse ecosystems is challenging because structuring drivers are often processes having diffuse impacts that attenuate from the people who were "managed" to the expected ecosystem-wide outcome. Coral reef fishes targeted for management only indirectly link to the ecosystem's foundation (reef corals). Three successively weakening interaction tiers separate management of fishing from coral abundance. We studied 12 islands along the 700-km eastern Caribbean archipelago, comparing fished and unfished coral reefs. Fishing reduced biomass of carnivorous (snappers and groupers) and herbivorous (parrotfish and surgeonfish) fishes. We document attenuating but important effects of managing fishing, which explained 37% of variance in parrotfish abundance, 20% of variance in harmful algal abundance, and 17% of variance in juvenile coral abundance. The explained variance increased when we quantified herbivory using area-specific bite rates. Local fisheries management resulted in a 62% increase in the archipelago's juvenile coral density, improving the ecosystem's recovery potential from major disturbances.

Attenuating effects of ecosystem management on coral reefs

PubMed Central

Rasher, Douglas B.; Stoyle, George

2018-01-01

Managing diverse ecosystems is challenging because structuring drivers are often processes having diffuse impacts that attenuate from the people who were “managed” to the expected ecosystem-wide outcome. Coral reef fishes targeted for management only indirectly link to the ecosystem’s foundation (reef corals). Three successively weakening interaction tiers separate management of fishing from coral abundance. We studied 12 islands along the 700-km eastern Caribbean archipelago, comparing fished and unfished coral reefs. Fishing reduced biomass of carnivorous (snappers and groupers) and herbivorous (parrotfish and surgeonfish) fishes. We document attenuating but important effects of managing fishing, which explained 37% of variance in parrotfish abundance, 20% of variance in harmful algal abundance, and 17% of variance in juvenile coral abundance. The explained variance increased when we quantified herbivory using area-specific bite rates. Local fisheries management resulted in a 62% increase in the archipelago’s juvenile coral density, improving the ecosystem’s recovery potential from major disturbances. PMID:29750192

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

PubMed

Barott, Katie L; Rodriguez-Mueller, Beltran; Youle, Merry; Marhaver, Kristen L; Vermeij, Mark J A; Smith, Jennifer E; Rohwer, Forest L

2012-04-22

Competition between reef-building corals and benthic algae is of key importance for reef dynamics. These interactions occur on many spatial scales, ranging from chemical to regional. Using microprobes, 16S rDNA pyrosequencing and underwater surveys, we examined the interactions between the reef-building coral Montastraea annularis and four types of benthic algae. The macroalgae Dictyota bartayresiana and Halimeda opuntia, as well as a mixed consortium of turf algae, caused hypoxia on the adjacent coral tissue. Turf algae were also associated with major shifts in the bacterial communities at the interaction zones, including more pathogens and virulence genes. In contrast to turf algae, interactions with crustose coralline algae (CCA) and M. annularis did not appear to be antagonistic at any scale. These zones were not hypoxic, the microbes were not pathogen-like and the abundance of coral-CCA interactions was positively correlated with per cent coral cover. We propose a model in which fleshy algae (i.e. some species of turf and fleshy macroalgae) alter benthic competition dynamics by stimulating bacterial respiration and promoting invasion of virulent bacteria on corals. This gives fleshy algae a competitive advantage over corals when human activities, such as overfishing and eutrophication, remove controls on algal abundance. Together, these results demonstrate the intricate connections and mechanisms that structure coral reefs.

Effect of severe hurricanes on biorock coral reef restoration projects in Grand Turk, Turks and Caicos Islands.

PubMed

Wells, Lucy; Perez, Fernando; Hibbert, Marlon; Clerveaux, Luc; Johnson, Jodi; Goreau, Thomas J

2010-10-01

Artificial reefs are often discouraged in shallow waters over concerns of storm damage to structures and surrounding habitat. Biorock coral reef restoration projects were initiated in waters around 5 m deep in Grand Turk, at Oasis (October 2006) and at Governor's Beach (November 2007). Hemi-cylindrical steel modules, 6m long were used, four modules at Oasis and six at Governor's Beach. Each project has over 1200 corals transplanted from sites with high sedimentation damage, and are regularly monitored for coral growth, mortality and fish populations. Corals show immediate growth over wires used to attach corals. Growth has been measured from photographs using a software program and is faster at Governor's Beach. After hurricanes Hanna and Ike (September 2008) the Governor's Beach structure was fully standing since the waves passed straight through with little damage, the Oasis structures which were tie-wired rather than welded had one module collapse (since been replaced with a new, welded structure). Hurricane Ike was the strongest hurricane on record to hit Grand Turk. Most cables were replaced following the hurricanes due to damage from debris and high wave action. The projects lost about a third of the corals due to hurricanes. Most of those lost had only been wired a few days before and had not yet attached themselves firmly. These projects have regenerated corals and fish populations in areas of barren sand or bedrock and are now attractive to snorkelers. High coral survival and low structural damage after hurricanes indicate that Biorock reef restoration can be effective in storm-impacted areas.

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.

Spatial and Seasonal Calcification in Corals and Calcareous Crusts in a Naturally Warm Coral Reef Region

NASA Astrophysics Data System (ADS)

Roik, A.; Roder, C.; Roethig, T.; Voolstra, C. R.

2016-02-01

The Red Sea harbors highly diverse and structurally complex coral reefs and is of interest for ocean warming studies. In the central and southern part, water temperatures rise above 30°C during summer, constituting one of the warmest coral reef environments worldwide. Additionally, seasonal variability of temperatures allows studying changes of environmental conditions and their effects on coral reef processes. To explore the influence of these warm and seasonally variable habitats on reef calcification, we measured in situ calcification of primary and secondary reef-builders in the central Red Sea. We collected calcification rates on the major habitat-forming coral genera Porites, Acropora, and Pocillopora, and also on calcareous crusts (CC). The study comprised forereef and backreef environments of three reefs along a cross-shelf gradient assessed over four seasons of the year. Calcification patterns of all coral genera were consistent across the shelf and highest in spring. In contrast to the corals, CC calcification strongly increased with distance from shore, but varied to a lesser extend over the seasons demonstrating lower calcification rates during spring and summer. Interestingly, reef calcification rates in the central Red Sea were on average in the range of data reported from the Caribbean and Indo-Pacific. For Acropora, annual average calcification rates were even at the lower end in comparison to studies from other locations. While coral calcification maxima typically have been observed during summer in many reef locations worldwide, we observed calcification maxima during spring in the central Red Sea indicating that summer temperatures may exceed the optima of reef calcifiers. Our study provides a baseline of calcification data for the region and serves as a foundation for comparative efforts to quantify the impact of future environmental change.

Re-evaluating the health of coral reef communities: baselines and evidence for human impacts across the central Pacific.

PubMed

Smith, Jennifer E; Brainard, Rusty; Carter, Amanda; Grillo, Saray; Edwards, Clinton; Harris, Jill; Lewis, Levi; Obura, David; Rohwer, Forest; Sala, Enric; Vroom, Peter S; Sandin, Stuart

2016-01-13

Numerous studies have documented declines in the abundance of reef-building corals over the last several decades and in some but not all cases, phase shifts to dominance by macroalgae have occurred. These assessments, however, often ignore the remainder of the benthos and thus provide limited information on the present-day structure and function of coral reef communities. Here, using an unprecedentedly large dataset collected within the last 10 years across 56 islands spanning five archipelagos in the central Pacific, we examine how benthic reef communities differ in the presence and absence of human populations. Using islands as replicates, we examine whether benthic community structure is associated with human habitation within and among archipelagos and across latitude. While there was no evidence for coral to macroalgal phase shifts across our dataset we did find that the majority of reefs on inhabited islands were dominated by fleshy non-reef-building organisms (turf algae, fleshy macroalgae and non-calcifying invertebrates). By contrast, benthic communities from uninhabited islands were more variable but in general supported more calcifiers and active reef builders (stony corals and crustose coralline algae). Our results suggest that cumulative human impacts across the central Pacific may be causing a reduction in the abundance of reef builders resulting in island scale phase shifts to dominance by fleshy organisms. © 2016 The Author(s).

Habitat preferences of a corallivorous reef fish: predation risk versus food quality

NASA Astrophysics Data System (ADS)

Brooker, R. M.; Munday, P. L.; Mcleod, I. M.; Jones, G. P.

2013-09-01

Many animals preferentially select a habitat from a range of those potentially available. However, the consequences of these preferences for distribution and abundance, and the underlying basis of habitat preferences are often unknown. The present study, conducted at Great Keppel Island, Australia, examined how distribution and abundance of an obligate corallivorous filefish, Oxymonacanthus longirostris, relates to coral architecture and diversity. The main drivers of the distribution and abundance of O. longirostris among reefs were coral species richness and availability of branching coral. Feeding territories had a higher percentage of Acropora coral than surrounding habitat. In addition, feeding territories had a higher percentage of the structurally important branching coral, Acropora nobilis, and a primary prey species, Acropora millepora. A series of pair-wise choice experiments in which both structural complexity and coral tissue quality were independently manipulated showed that habitat choice was primarily based on structural complexity and shelter characteristics. In addition, the choice for the preferred coral ( A. nobilis) was stronger in the presence of a piscivorous fish. These results indicate that species-diverse coral habitats, which provide sufficient structural complexity along with nutritionally important prey, are essential for population persistence of this small, corallivorous reef fish.

Indices for assessing coral reef fish biodiversity: the need for a change in habits.

PubMed

Loiseau, Nicolas; Gaertner, Jean-Claude

2015-09-01

We present the first representative and quantified overview of the indices used worldwide for assessing the biodiversity of coral reef fishes. On this basis, we discuss the suitability and drawbacks of the indices most widely used in the assessment of coral fish biodiversity. An extensive and systematic survey of the literature focused on coral reef fish biodiversity was conducted from 1990 up to the present. We found that the multicomponent aspect of biodiversity, which is considered as a key feature of biodiversity for numerous terrestrial and marine ecosystems, has been poorly taken into account in coral reef fish studies. Species richness is still strongly dominant while other diversity components, such as functional diversity, are underestimated even when functional information is available. We also demonstrate that the reason for choosing particular indices is often unclear, mainly based on empirical rationales and/or the reproduction of widespread habits, but generally with no clear relevance with regard to the aims of the studies. As a result, the most widely used indices (species richness, Shannon, etc.) would appear to be poorly suited to meeting the main challenges facing the monitoring of coral reef fish biodiversity in the future. Our results clearly show that coral reef scientists should rather take advantage of the multicomponent aspect of biodiversity. To facilitate this approach, we propose general guidelines to serve as a basis for the selection of indices that provide complementary and relevant information for monitoring the response of coral reef fish biodiversity in the face of structuring factors (natural or anthropic). The aim of these guidelines was to achieve a better match between the properties of the selected indices and the context of each study (e.g. expected effect of the main structuring factors, nature of data available).

Diel Variability in Seawater pH Relates to Calcification and Benthic Community Structure on Coral Reefs

PubMed Central

Martz, Todd R.; Brainard, Russell E.

2012-01-01

Community structure and assembly are determined in part by environmental heterogeneity. While reef-building corals respond negatively to warming (i.e. bleaching events) and ocean acidification (OA), the extent of present-day natural variability in pH on shallow reefs and ecological consequences for benthic assemblages is unknown. We documented high resolution temporal patterns in temperature and pH from three reefs in the central Pacific and examined how these data relate to community development and net accretion rates of early successional benthic organisms. These reefs experienced substantial diel fluctuations in temperature (0.78°C) and pH (>0.2) similar to the magnitude of ‘warming’ and ‘acidification’ expected over the next century. Where daily pH within the benthic boundary layer failed to exceed pelagic climatological seasonal lows, net accretion was slower and fleshy, non-calcifying benthic organisms dominated space. Thus, key aspects of coral reef ecosystem structure and function are presently related to natural diurnal variability in pH. PMID:22952785

Diverse coral communities in mangrove habitats suggest a novel refuge from climate change

NASA Astrophysics Data System (ADS)

Yates, K. K.; Rogers, C. S.; Herlan, J. J.; Brooks, G. R.; Smiley, N. A.; Larson, R. A.

2014-08-01

Risk analyses indicate that more than 90% of the world's reefs will be threatened by climate change and local anthropogenic impacts by the year 2030 under "business-as-usual" climate scenarios. Increasing temperatures and solar radiation cause coral bleaching that has resulted in extensive coral mortality. Increasing carbon dioxide reduces seawater pH, slows coral growth, and may cause loss of reef structure. Management strategies include establishment of marine protected areas with environmental conditions that promote reef resiliency. However, few resilient reefs have been identified, and resiliency factors are poorly defined. Here we characterize the first natural, non-reef coral refuge from thermal stress and ocean acidification and identify resiliency factors for mangrove-coral habitats. We measured diurnal and seasonal variations in temperature, salinity, photosynthetically active radiation (PAR), and seawater chemistry; characterized substrate parameters; and examined water circulation patterns in mangrove communities where scleractinian corals are growing attached to and under mangrove prop roots in Hurricane Hole, St. John, US Virgin Islands. Additionally, we inventoried the coral species and quantified incidences of coral bleaching, mortality, and recovery for two major reef-building corals, Colpophyllia natans and Diploria labyrinthiformis, growing in mangrove-shaded and exposed (unshaded) areas. Over 30 species of scleractinian corals were growing in association with mangroves. Corals were thriving in low-light (more than 70% attenuation of incident PAR) from mangrove shading and at higher temperatures than nearby reef tract corals. A higher percentage of C. natans colonies were living shaded by mangroves, and no shaded colonies were bleached. Fewer D. labyrinthiformis colonies were shaded by mangroves, however more unshaded colonies were bleached. A combination of substrate and habitat heterogeneity, proximity of different habitat types, hydrographic conditions, and biological influences on seawater chemistry generate chemical conditions that buffer against ocean acidification. This previously undocumented refuge for corals provides evidence for adaptation of coastal organisms and ecosystem transition due to recent climate change. Identifying and protecting other natural, non-reef coral refuges is critical for sustaining corals and other reef species into the future.

Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea.

PubMed

Khalil, Maha T; Bouwmeester, Jessica; Berumen, Michael L

2017-01-01

Local-scale ecological information is critical as a sound basis for spatial management and conservation and as support for ongoing research in relatively unstudied areas. We conducted visual surveys of fish and benthic communities on nine reefs (3-24 km from shore) in the Thuwal area of the central Saudi Arabian Red Sea. Fish biomass increased with increasing distance from shore, but was generally low compared to reefs experiencing minimal human influence around the world. All reefs had a herbivore-dominated trophic structure and few top predators, such as sharks, jacks, or large groupers. Coral cover was considerably lower on inshore reefs, likely due to a 2010 bleaching event. Community analyses showed inshore reefs to be characterized by turf algae, slower-growing corals, lower herbivore diversity, and highly abundant turf-farming damselfishes. Offshore reefs had more planktivorous fishes, a more diverse herbivore assemblage, and faster-growing corals . All reefs appear to be impacted by overfishing, and inshore reefs seem more vulnerable to thermal bleaching. The study provides a description of the spatial variation in biomass and community structure in the central Saudi Arabian Red Sea and provides a basis for spatial prioritization and subsequent marine protected area design in Thuwal.

A matter of scale: damage from Hurricane Hugo (1989) to U.S. Virgin Islands reefs at the colony, community and whole reef level

USGS Publications Warehouse

Rogers, Caroline S.

1993-01-01

Studies at Buck Island Reef National Monument (St. Croix) and Virgin Islands National Park (St. John) by scientists in the U.S. National Park Service Coral Reef Assessment Program re- vealed the effects of Humcane Hugo on individual coral species, community parameters, and overall reef structure. Effects of the storm varied with depth, coral species, location relative to the storm path, character of the pre-storm communities, and ecological history. Live coral cover, initially less than 30% at all sites, dropped by 40 to 73%. Cover by the dominant species Montastrea annularis de- clined about 35% on the St. John reefs. At Buck Island, Acropora palmata cover, already reduced from 85% to 5% by white band disease and storms, fell to 0.8% after Hugo. Some areas on the south side of Buck Island were reduced to rubble pave- ment while other areas escaped serious damage. Data from cores at Buck Island reveal the influence of wave energy and storm frequency on overall reef character. Patchiness and variation in the responses of different species, zones, and entire reefs to the storm suggest that assessment of long-term trends in reef structure and composition requires analysis of changes at permanent study sites distributed over large areas.

Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea

PubMed Central

Bouwmeester, Jessica; Berumen, Michael L.

2017-01-01

Local-scale ecological information is critical as a sound basis for spatial management and conservation and as support for ongoing research in relatively unstudied areas. We conducted visual surveys of fish and benthic communities on nine reefs (3–24 km from shore) in the Thuwal area of the central Saudi Arabian Red Sea. Fish biomass increased with increasing distance from shore, but was generally low compared to reefs experiencing minimal human influence around the world. All reefs had a herbivore-dominated trophic structure and few top predators, such as sharks, jacks, or large groupers. Coral cover was considerably lower on inshore reefs, likely due to a 2010 bleaching event. Community analyses showed inshore reefs to be characterized by turf algae, slower-growing corals, lower herbivore diversity, and highly abundant turf-farming damselfishes. Offshore reefs had more planktivorous fishes, a more diverse herbivore assemblage, and faster-growing corals. All reefs appear to be impacted by overfishing, and inshore reefs seem more vulnerable to thermal bleaching. The study provides a description of the spatial variation in biomass and community structure in the central Saudi Arabian Red Sea and provides a basis for spatial prioritization and subsequent marine protected area design in Thuwal. PMID:28603671

Occurrence and distribution of antifouling biocide Irgarol-1051 in coral reef ecosystems, Zanzibar.

PubMed

Sheikh, Mohammed A; Juma, Fatma S; Staehr, Peter; Dahl, Karsten; Rashid, Rashid J; Mohammed, Mohammed S; Ussi, Ali M; Ali, Hassan R

2016-08-15

2-methythiol-4-tert-butylamino-6-cyclopropylamino-s-triazine (Irgarol-1051) has been widely used as effective alternative antifouling paint in marine structures including ships. However, it has been causing deleterious effects to marine organisms including reef building corals. The main objective of this study was to establish baseline levels of Irgarol-1051 around coral reefs and nearby ecosystems along coastline of Zanzibar Island. The levels of Irgarol-1051 ranged from 1.35ng/L around coral reefs to 15.44ng/L around harbor with average concentration of 4.11 (mean)±0.57 (SD) ng/L. This is below Environmental Risk Limit of 24ng/L as proposed by Dutch Authorities which suggests that the contamination is not alarming especially for coral reef ecosystem health. The main possible sources of the contamination are from shipping activities. This paper provides important baseline information of Irgarol-1051 around the coral reef ecosystems within the Western Indian Ocean (WIO) region and may be useful for formulation of marine conservation strategies and policies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Using virtual reality to estimate aesthetic values of coral reefs

PubMed Central

Clifford, Sam; Caley, M. Julian; Pearse, Alan R.; Brown, Ross; James, Allan; Christensen, Bryce; Bednarz, Tomasz; Anthony, Ken; González-Rivero, Manuel; Mengersen, Kerrie; Peterson, Erin E.

2018-01-01

Aesthetic value, or beauty, is important to the relationship between humans and natural environments and is, therefore, a fundamental socio-economic attribute of conservation alongside other ecosystem services. However, beauty is difficult to quantify and is not estimated well using traditional approaches to monitoring coral-reef aesthetics. To improve the estimation of ecosystem aesthetic values, we developed and implemented a novel framework used to quantify features of coral-reef aesthetics based on people's perceptions of beauty. Three observer groups with different experience to reef environments (Marine Scientist, Experienced Diver and Citizen) were virtually immersed in Australian's Great Barrier Reef (GBR) using 360° images. Perceptions of beauty and observations were used to assess the importance of eight potential attributes of reef-aesthetic value. Among these, heterogeneity, defined by structural complexity and colour diversity, was positively associated with coral-reef-aesthetic values. There were no group-level differences in the way the observer groups perceived reef aesthetics suggesting that past experiences with coral reefs do not necessarily influence the perception of beauty by the observer. The framework developed here provides a generic tool to help identify indicators of aesthetic value applicable to a wide variety of natural systems. The ability to estimate aesthetic values robustly adds an important dimension to the holistic conservation of the GBR, coral reefs worldwide and other natural ecosystems. PMID:29765676

Using virtual reality to estimate aesthetic values of coral reefs.

PubMed

Vercelloni, Julie; Clifford, Sam; Caley, M Julian; Pearse, Alan R; Brown, Ross; James, Allan; Christensen, Bryce; Bednarz, Tomasz; Anthony, Ken; González-Rivero, Manuel; Mengersen, Kerrie; Peterson, Erin E

2018-04-01

Aesthetic value, or beauty, is important to the relationship between humans and natural environments and is, therefore, a fundamental socio-economic attribute of conservation alongside other ecosystem services. However, beauty is difficult to quantify and is not estimated well using traditional approaches to monitoring coral-reef aesthetics. To improve the estimation of ecosystem aesthetic values, we developed and implemented a novel framework used to quantify features of coral-reef aesthetics based on people's perceptions of beauty. Three observer groups with different experience to reef environments (Marine Scientist, Experienced Diver and Citizen) were virtually immersed in Australian's Great Barrier Reef (GBR) using 360° images. Perceptions of beauty and observations were used to assess the importance of eight potential attributes of reef-aesthetic value. Among these, heterogeneity, defined by structural complexity and colour diversity, was positively associated with coral-reef-aesthetic values. There were no group-level differences in the way the observer groups perceived reef aesthetics suggesting that past experiences with coral reefs do not necessarily influence the perception of beauty by the observer. The framework developed here provides a generic tool to help identify indicators of aesthetic value applicable to a wide variety of natural systems. The ability to estimate aesthetic values robustly adds an important dimension to the holistic conservation of the GBR, coral reefs worldwide and other natural ecosystems.

Mass coral bleaching causes biotic homogenization of reef fish assemblages.

PubMed

Richardson, Laura E; Graham, Nicholas A J; Pratchett, Morgan S; Eurich, Jacob G; Hoey, Andrew S

2018-04-06

Global climate change is altering community composition across many ecosystems due to nonrandom species turnover, typically characterized by the loss of specialist species and increasing similarity of biological communities across spatial scales. As anthropogenic disturbances continue to alter species composition globally, there is a growing need to identify how species responses influence the establishment of distinct assemblages, such that management actions may be appropriately assigned. Here, we use trait-based analyses to compare temporal changes in five complementary indices of reef fish assemblage structure among six taxonomically distinct coral reef habitats exposed to a system-wide thermal stress event. Our results revealed increased taxonomic and functional similarity of previously distinct reef fish assemblages following mass coral bleaching, with changes characterized by subtle, but significant, shifts toward predominance of small-bodied, algal-farming habitat generalists. Furthermore, while the taxonomic or functional richness of fish assemblages did not change across all habitats, an increase in functional originality indicated an overall loss of functional redundancy. We also found that prebleaching coral composition better predicted changes in fish assemblage structure than the magnitude of coral loss. These results emphasize how measures of alpha diversity can mask important changes in the structure and functioning of ecosystems as assemblages reorganize. Our findings also highlight the role of coral species composition in structuring communities and influencing the diversity of responses of reef fishes to disturbance. As new coral species configurations emerge, their desirability will hinge upon the composition of associated species and their capacity to maintain key ecological processes in spite of ongoing disturbances. © 2018 John Wiley & Sons Ltd.

First observations of the structure and megafaunal community of a large Lophelia reef on the Ghanaian shelf (the Gulf of Guinea)

NASA Astrophysics Data System (ADS)

Buhl-Mortensen, L.; Serigstad, B.; Buhl-Mortensen, P.; Olsen, M. N.; Ostrowski, M.; Błażewicz-Paszkowycz, M.; Appoh, E.

2017-03-01

The distribution of cold-water coral reefs is relatively well known in the North-east Atlantic as compared to the Central-east Atlantic, where only a few documentations exist from low latitudes. In 2012 an initial survey was conducted on a reef situated at 400 m depth on the continental shelf off Ghana. The reef corals and fauna were visually documented using a Video Assisted Multi Sampler (VAMS) coupled with an ROV. Here we present the results from three dives on the 1400 m long and 70 m high reef with an ambient temperatures between 9 and 10 °C. The banana shaped reef was oriented perpendicular to the main current, the convex side facing the current and there was no sign of human impact. The great height of the reef is probably a result of undisturbed growth for more than 20,000 years. On the Norwegian continental shelf the largest reefs are around 30 m high and have been aged to 9000 years. The reef morphology resembles that of Northeast Atlantic Lophelia reefs. The main reef building coral was Lophelia pertusa with contribution from Madrepora oculata, Solenosmilia variabilis, and occasional occurrences of Dendrophyllia cf. alternata. The skeleton of Aphrocallistes beatrix (Hexactinellidae) contributed to the reef framework and the reef consisted of 46% coral blocks 22% sediment, 13% coral rubble, 11% sponge skeleton and 8% live corals. A rich megafauna of 31 taxa was recorded and most frequent was Acesta excavate (bivalve), Aphrocallistes beatrix (with an associated Zooanthida on 39% of the colonies), squat lobsters, hydroids and bryozoans. Six fish species were recorded of which the Sebastidae Helicolenus dactylopterus and Nettastoma melanurum were found amongst coral blocks. The reef community showed several similarities with the northern reefs with sponges, Sebastes spp., squat lobsters, and Acesta excavata being common megafauna associates. In contrast the gorgonian corals that are characteristic of the northern reefs seemed to be lacking and Hexactinellidae rather than Demospongia were common on the reef and contributed to the reef framework. Crabs that are uncommon on northern reefs were frequently encountered.

Quantifying Ocean Acidification and its Impacts to Coral Reef Ecosystems

NASA Astrophysics Data System (ADS)

Manzello, D.; Gledhill, D. K.; Enochs, I.; Andersson, A. J.

2013-05-01

Ocean Acidification (OA) describes the uptake of anthropogenic CO2 by the world's oceans and consequent decline in seawater pH and calcium carbonate saturation state. OA is of particular concern for coral reef ecosystems because it is expected to reduce the calcification rates of reef-building corals and other calcifiers, and may simultaneously increase the erosive abilities of key bioeroding taxa. Despite these concerns, we have little understanding of how OA will manifest in the real-world or, if, and how much of the world-wide trajectory of reef decline can be attributed to OA. With this in mind, we will present recommendations for monitoring OA of coral reef waters, as well as its ecosystem impacts over time. Different approaches and metrics, including their individual strengths and weaknesses, will be discussed. The ultimate goal of these efforts is to quantify the effects of OA on coral reef ecosystems in the real-world to robustly predict their structure and function in a high-CO2 world.

Expectations and Outcomes of Reserve Network Performance following Re-zoning of the Great Barrier Reef Marine Park.

PubMed

Emslie, Michael J; Logan, Murray; Williamson, David H; Ayling, Anthony M; MacNeil, M Aaron; Ceccarelli, Daniela; Cheal, Alistair J; Evans, Richard D; Johns, Kerryn A; Jonker, Michelle J; Miller, Ian R; Osborne, Kate; Russ, Garry R; Sweatman, Hugh P A

2015-04-20

Networks of no-take marine reserves (NTMRs) are widely advocated for preserving exploited fish stocks and for conserving biodiversity. We used underwater visual surveys of coral reef fish and benthic communities to quantify the short- to medium-term (5 to 30 years) ecological effects of the establishment of NTMRs within the Great Barrier Reef Marine Park (GBRMP). The density, mean length, and biomass of principal fishery species, coral trout (Plectropomus spp., Variola spp.), were consistently greater in NTMRs than on fished reefs over both the short and medium term. However, there were no clear or consistent differences in the structure of fish or benthic assemblages, non-target fish density, fish species richness, or coral cover between NTMR and fished reefs. There was no indication that the displacement and concentration of fishing effort reduced coral trout populations on fished reefs. A severe tropical cyclone impacted many survey reefs during the study, causing similar declines in coral cover and fish density on both NTMR and fished reefs. However, coral trout biomass declined only on fished reefs after the cyclone. The GBRMP is performing as expected in terms of the protection of fished stocks and biodiversity for a developed country in which fishing is not excessive and targets a narrow range of species. NTMRs cannot protect coral reefs directly from acute regional-scale disturbance but, after a strong tropical cyclone, impacted NTMR reefs supported higher biomass of key fishery-targeted species and so should provide valuable sources of larvae to enhance population recovery and long-term persistence. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coral reefs under rapid climate change and ocean acidification.

PubMed

Hoegh-Guldberg, O; Mumby, P J; Hooten, A J; Steneck, R S; Greenfield, P; Gomez, E; Harvell, C D; Sale, P F; Edwards, A J; Caldeira, K; Knowlton, N; Eakin, C M; Iglesias-Prieto, R; Muthiga, N; Bradbury, R H; Dubi, A; Hatziolos, M E

2007-12-14

Atmospheric carbon dioxide concentration is expected to exceed 500 parts per million and global temperatures to rise by at least 2 degrees C by 2050 to 2100, values that significantly exceed those of at least the past 420,000 years during which most extant marine organisms evolved. Under conditions expected in the 21st century, global warming and ocean acidification will compromise carbonate accretion, with corals becoming increasingly rare on reef systems. The result will be less diverse reef communities and carbonate reef structures that fail to be maintained. Climate change also exacerbates local stresses from declining water quality and overexploitation of key species, driving reefs increasingly toward the tipping point for functional collapse. This review presents future scenarios for coral reefs that predict increasingly serious consequences for reef-associated fisheries, tourism, coastal protection, and people. As the International Year of the Reef 2008 begins, scaled-up management intervention and decisive action on global emissions are required if the loss of coral-dominated ecosystems is to be avoided.

Host population genetic structure and zooxanthellae diversity of two reef-building coral species along the Florida Reef Tract and wider Caribbean

NASA Astrophysics Data System (ADS)

Baums, I. B.; Johnson, M. E.; Devlin-Durante, M. K.; Miller, M. W.

2010-12-01

In preparation for a large-scale coral restoration project, we surveyed host population genetic structure and symbiont diversity of two reef-building corals in four reef zones along the Florida reef tract (FRT). There was no evidence for coral population subdivision along the FRT in Acropora cervicornis or Montastraea faveolata based on microsatellite markers. However, in A. cervicornis, significant genetic differentiation was apparent when extending the analysis to broader scales (Caribbean). Clade diversity of the zooxanthellae differed along the FRT. A. cervicornis harbored mostly clade A with clade D zooxanthellae being prominent in colonies growing inshore and in the mid-channel zones that experience greater temperature fluctuations and receive significant nutrient and sediment input. M. faveolata harbored a more diverse array of symbionts, and variation in symbiont diversity among four habitat zones was more subtle but still significant. Implications of these results are discussed for ongoing restoration and conservation work.

Anticipative management for coral reef ecosystem services in the 21st century.

PubMed

Rogers, Alice; Harborne, Alastair R; Brown, Christopher J; Bozec, Yves-Marie; Castro, Carolina; Chollett, Iliana; Hock, Karlo; Knowland, Cheryl A; Marshell, Alyssa; Ortiz, Juan C; Razak, Tries; Roff, George; Samper-Villarreal, Jimena; Saunders, Megan I; Wolff, Nicholas H; Mumby, Peter J

2015-02-01

Under projections of global climate change and other stressors, significant changes in the ecology, structure and function of coral reefs are predicted. Current management strategies tend to look to the past to set goals, focusing on halting declines and restoring baseline conditions. Here, we explore a complementary approach to decision making that is based on the anticipation of future changes in ecosystem state, function and services. Reviewing the existing literature and utilizing a scenario planning approach, we explore how the structure of coral reef communities might change in the future in response to global climate change and overfishing. We incorporate uncertainties in our predictions by considering heterogeneity in reef types in relation to structural complexity and primary productivity. We examine 14 ecosystem services provided by reefs, and rate their sensitivity to a range of future scenarios and management options. Our predictions suggest that the efficacy of management is highly dependent on biophysical characteristics and reef state. Reserves are currently widely used and are predicted to remain effective for reefs with high structural complexity. However, when complexity is lost, maximizing service provision requires a broader portfolio of management approaches, including the provision of artificial complexity, coral restoration, fish aggregation devices and herbivore management. Increased use of such management tools will require capacity building and technique refinement and we therefore conclude that diversification of our management toolbox should be considered urgently to prepare for the challenges of managing reefs into the 21st century. © 2014 John Wiley & Sons Ltd.

Toward a Marine Ecological Forecasting System

DTIC Science & Technology

2010-06-01

advance. Two beaches in Lake Michigan have been selected for initial implementation. Forecasting Coral Bleaching in relation to Ocean Temperatures...The coral reef is a unique and very rich ecosystem which supports a vast array of animal and plant species. Corals form the structural and...ecological foundation of the reef system, and consist of a symbiotic relationship between the coral animal (polyp) and associated algae (zooxanthellae

A unified model explains commonness and rarity on coral reefs.

PubMed

Connolly, Sean R; Hughes, Terry P; Bellwood, David R

2017-04-01

Abundance patterns in ecological communities have important implications for biodiversity maintenance and ecosystem functioning. However, ecological theory has been largely unsuccessful at capturing multiple macroecological abundance patterns simultaneously. Here, we propose a parsimonious model that unifies widespread ecological relationships involving local aggregation, species-abundance distributions, and species associations, and we test this model against the metacommunity structure of reef-building corals and coral reef fishes across the western and central Pacific. For both corals and fishes, the unified model simultaneously captures extremely well local species-abundance distributions, interspecific variation in the strength of spatial aggregation, patterns of community similarity, species accumulation, and regional species richness, performing far better than alternative models also examined here and in previous work on coral reefs. Our approach contributes to the development of synthetic theory for large-scale patterns of community structure in nature, and to addressing ongoing challenges in biodiversity conservation at macroecological scales. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Integration of coral reef ecosystem process studies and remote sensing: Chapter 5

USGS Publications Warehouse

Brook, John; Yates, Kimberly; Halley, Robert

2006-01-01

Worldwide, local-scale anthropogenic stress combined with global climate change is driving shifts in the state of reef benthic communities from coral-rich to micro- or macroalgal-dominated (Knowlton, 1992; Done, 1999). Such phase shifts in reef benthic communities may be either abrupt or gradual, and case studies from diverse ocean basins demonstrate that recovery, while uncertain (Hughes, 1994), typically involves progression through successional stages (Done, 1992). These transitions in benthic community structure involve changes in community metabolism, and accordingly, the holistic evaluation of associated biogeochemical variables is of great intrinsic value (Done, 1992). Effective reef management requires advance prediction of coral reef alteration in the face of anthropogenic stress and change in the global environment (Hatcher, 1997a). In practice, this goal requires techniques that can rapidly discern, at an early stage, sublethal effects that may cause long-term increases in mortality (brown, 1988; Grigg and Dollar, 1990). Such methods would improve our understanding of the differences in the population, community, and ecosystem structure, as well as function, between pristine and degraded reefs. This knowledge base could then support scientifically based management strategies (Done, 1992). Brown (1988) noted the general lack of rigor in the assessment of stress on coral reefs and suggested that more quantitative approaches than currently exist are needed to allow objective understanding of coral reef dynamics. Sensitive techniques for the timely appraisal of pollution effects or generalized endemic stress in coral reefs are sorely lacking (Grigg and Dollar, 1990; Wilkinsin, 1992). Moreover, monitoring methods based on population inventories, sclerochronology, or reproductive biology tend to myopic and may give inconsistent results. Ideally, an improved means of evaluating reef stress would discriminate mortality due to natural causes from morality to anthropogenic causes (Brown, 1988). Models of coral reef ecosystems, parameterized by process measurements and scaled in time-space using remote sensing, have the potential to address pressing research questions that are central to devising valid management strategies (Grigg el al., 1984; Hatcher, 1997b). To attain this goal, ecosystem-level models that integrate studies of physical and chemical forcing with observed biological and geological responses are required. This interdisciplinary approach to understanding reef biogeochemical dynamics can allow investigations that integrate the scales of time and space (Hatcher, 1997a), thereby enabling prediction of coral reef change (Andréfouët and Payri, 2001). In turn, prediction of holistic ecosystem function within various environmental focusing scenarios has substantial promise in mitigating future disturbance. Indeed, management of coral reefs at the ecosystem level has been suggested as the only meaningful approach to preserving coral reefs (Bohnsack and Ault, 1996; Christensen et al., 1996).

The importance of sponges and mangroves in supporting fish communities on degraded coral reefs in Caribbean Panama.

PubMed

Seemann, Janina; Yingst, Alexandra; Stuart-Smith, Rick D; Edgar, Graham J; Altieri, Andrew H

2018-01-01

Fish communities associated with coral reefs worldwide are threatened by habitat degradation and overexploitation. We assessed coral reefs, mangrove fringes, and seagrass meadows on the Caribbean coast of Panama to explore the influences of their proximity to one another, habitat cover, and environmental characteristics in sustaining biomass, species richness and trophic structure of fish communities in a degraded tropical ecosystem. We found 94% of all fish across all habitat types were of small body size (≤10 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Total fish biomass was very low, with the trend of small fishes from low trophic levels over-represented, and top predators under-represented, relative to coral reefs elsewhere in the Caribbean. For example, herbivorous fishes comprised 27% of total fish biomass in Panama relative to 10% in the wider Caribbean, and the small parrotfish Scarus iseri comprised 72% of the parrotfish biomass. We found evidence that non-coral biogenic habitats support reef-associated fish communities. In particular, the abundance of sponges on a given reef and proximity of mangroves were found to be important positive correlates of reef fish species richness, biomass, abundance and trophic structure. Our study indicates that a diverse fish community can persist on degraded coral reefs, and that the availability and arrangement within the seascape of other habitat-forming organisms, including sponges and mangroves, is critical to the maintenance of functional processes in such ecosystems.

The importance of sponges and mangroves in supporting fish communities on degraded coral reefs in Caribbean Panama

PubMed Central

Yingst, Alexandra; Stuart-Smith, Rick D.; Edgar, Graham J.; Altieri, Andrew H.

2018-01-01

Fish communities associated with coral reefs worldwide are threatened by habitat degradation and overexploitation. We assessed coral reefs, mangrove fringes, and seagrass meadows on the Caribbean coast of Panama to explore the influences of their proximity to one another, habitat cover, and environmental characteristics in sustaining biomass, species richness and trophic structure of fish communities in a degraded tropical ecosystem. We found 94% of all fish across all habitat types were of small body size (≤10 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Total fish biomass was very low, with the trend of small fishes from low trophic levels over-represented, and top predators under-represented, relative to coral reefs elsewhere in the Caribbean. For example, herbivorous fishes comprised 27% of total fish biomass in Panama relative to 10% in the wider Caribbean, and the small parrotfish Scarus iseri comprised 72% of the parrotfish biomass. We found evidence that non-coral biogenic habitats support reef-associated fish communities. In particular, the abundance of sponges on a given reef and proximity of mangroves were found to be important positive correlates of reef fish species richness, biomass, abundance and trophic structure. Our study indicates that a diverse fish community can persist on degraded coral reefs, and that the availability and arrangement within the seascape of other habitat-forming organisms, including sponges and mangroves, is critical to the maintenance of functional processes in such ecosystems. PMID:29610704

Lag effects in the impacts of mass coral bleaching on coral reef fish, fisheries, and ecosystems.

PubMed

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

2007-10-01

Recent episodes of coral bleaching have led to wide-scale loss of reef corals and raised concerns over the effectiveness of existing conservation and management efforts. The 1998 bleaching event was most severe in the western Indian Ocean, where coral declined by up to 90% in some locations. Using fisheries-independent data, we assessed the long-term impacts of this event on fishery target species in the Seychelles, the overall size structure of the fish assemblage, and the effectiveness of two marine protected areas (MPAs) in protecting fish communities. The biomass of fished species above the size retained in fish traps changed little between 1994 and 2005, indicating no current effect on fishery yields. Biomass remained higher in MPAs, indicating they were effective in protecting fish stocks. Nevertheless, the size structure of the fish communities, as described with size-spectra analysis, changed in both fished areas and MPAs, with a decline in smaller fish (<30 cm) and an increase in larger fish (>45 cm). We believe this represents a time-lag response to a reduction in reef structural complexity brought about because fishes are being lost through natural mortality and fishing, and are not being replaced by juveniles. This effect is expected to be greater in terms of fisheries productivity and, because congruent patterns are observed for herbivores, suggests that MPAs do not offer coral reefs long-term resilience to bleaching events. Corallivores and planktivores declined strikingly in abundance, particularly in MPAs, and this decline was associated with a similar pattern of decline in their preferred corals. We suggest that climate-mediated disturbances, such as coral bleaching, be at the fore of conservation planning for coral reefs.

Florida Integrated Science Center (FISC) Coral Reef Research

USGS Publications Warehouse

Poore, D.Z.

2008-01-01

Coral reefs provide important ecosystem services such as shoreline protection and the support of lucrative industries including fisheries and tourism. Such ecosystem services are being compromised as reefs decline due to coral disease, climate change, overfishing, and pollution. There is a need for focused, integrated science to understand the complex ecological interactions and effects of these many stressors and to provide information that will effectively guide policies and best management practices to preserve and restore these important resources. The U.S. Geological Survey Florida Integrated Science Center (USGS-FISC) is conducting a coordinated Coral Reef Research Project beginning in 2009. Specific research topics are aimed at addressing priorities identified in the 'Strategic Science for Coral Ecosystems 2007-2011' document (U.S. Geological Survey, 2007). Planned research will include a blend of historical, monitoring, and process studies aimed at improving our understanding of the development, current status and function, and likely future changes in coral ecosystems. Topics such as habitat characterization and distribution, coral disease, and trends in biogenic calcification are major themes of understanding reef structure, ecological integrity, and responses to global change.

River discharge reduces reef coral diversity in Palau.

PubMed

Golbuu, Yimnang; van Woesik, Robert; Richmond, Robert H; Harrison, Peter; Fabricius, Katharina E

2011-04-01

Coral community structure is often governed by a suite of processes that are becoming increasingly influenced by land-use changes and related terrestrial discharges. We studied sites along a watershed gradient to examine both the physical environment and the associated biological communities. Transplanted corals showed no differences in growth rates and mortality along the watershed gradient. However, coral cover, coral richness, and coral colony density increased with increasing distance from the mouth of the bay. There was a negative relationship between coral cover and mean suspended solids concentration. Negative relationships were also found between terrigenous sedimentation rates and the richness of adult and juvenile corals. These results have major implications not only for Pacific islands but for all countries with reef systems downstream of rivers. Land development very often leads to increases in river runoff and suspended solids concentrations that reduce coral cover and coral diversity on adjacent reefs. Copyright © 2010 Elsevier Ltd. All rights reserved.

Coral-reef front migration in the Ryukyu Arc: responses of high latitude coral reefs to Quaternary climatic changes in North Western Pacific

NASA Astrophysics Data System (ADS)

Matsuda, H.; Iryu, Y.; Machiyama, H.

2003-04-01

Coral reefs are tropic to subtropic coastal ecosystems comprising very diverse organisms. Their community structure and geographic and local distribution are highly controlled by various environmental factors. Thus, their ancient counterparts, reef deposits, provide important, high-resolution records of geoscientific events in tropic to subtropic shallow waters, such as vertical and lateral tectonic movements, sea-level fluctuations, paleoclimatic changes, and paleoceanographic variations. In order to clarify relationships between reef formation and geoscientific events, it is necessary to investigate the reef deposits at relatively higher latitudes within reef provinces, because such reefs were considered to be more sensitive to the environmental changes than those in proximal areas. It can be, therefore, considered that the northern or southern limit of reef formation, herein termed the 'coral-reef front', may have migrated to higher and lower latitudes, respectively, responding to Pleistocene global warming and cooling associated with rapid, cyclic changes in climate and oceanographic conditions and with glacioeustatic sea-level rises and falls. Thus, this study mainly aims (1) to depict paleoeclimatic and paleoceanographic fluctuations in tropic to subtropic shallow-waters in details by reconstructing the coral-reef front migration, (2) how and to what extent the reefs responded to rapid environmental changes, and (3) to evaluate a role of coral reefs in a global carbon cycle. To resolve the problems described above, the Ryukyu Islands are one of the best fields. In this proposal, we will insist that the multiple drilling that covers submarine (IODP) and land (ICDP) areas is the only way to complete our purposes.

Small Marine Protected Areas in Fiji Provide Refuge for Reef Fish Assemblages, Feeding Groups, and Corals.

PubMed

Bonaldo, Roberta M; Pires, Mathias M; Guimarães, Paulo Roberto; Hoey, Andrew S; Hay, Mark E

2017-01-01

The establishment of no-take marine protected areas (MPAs) on coral reefs is a common management strategy for conserving the diversity, abundance, and biomass of reef organisms. Generally, well-managed and enforced MPAs can increase or maintain the diversity and function of the enclosed coral reef, with some of the benefits extending to adjacent non-protected reefs. A fundamental question in coral reef conservation is whether these benefits arise within small MPAs (<1 km2), because larval input of reef organisms is largely decoupled from local adult reproduction. We examined the structure of fish assemblages, composition of fish feeding groups, benthic cover, and key ecosystem processes (grazing, macroalgal browsing, and coral replenishment) in three small (0.5-0.8 km2) no-take MPAs and adjacent areas where fisheries are allowed (non-MPAs) on coral reefs in Fiji. The MPAs exhibited greater species richness, density, and biomass of fishes than non-MPAs. Furthermore, MPAs contained a greater abundance and biomass of grazing herbivores and piscivores as well as a greater abundance of cleaners than fished areas. We also found differences in fish associations when foraging, with feeding groups being generally more diverse and having greater biomass within MPAs than adjacent non-MPAs. Grazing by parrotfishes was 3-6 times greater, and macroalgal browsing was 3-5 times greater in MPAs than in non-MPAs. On average, MPAs had 260-280% as much coral cover and only 5-25% as much macroalgal cover as their paired non-MPA sites. Finally, two of the three MPAs had three-fold more coral recruits than adjacent non-MPAs. The results of this study indicate that small MPAs benefit not only populations of reef fishes, but also enhance ecosystem processes that are critical to reef resilience within the MPAs.

Unmixing-Based Denoising as a Pre-Processing Step for Coral Reef Analysis

NASA Astrophysics Data System (ADS)

Cerra, D.; Traganos, D.; Gege, P.; Reinartz, P.

2017-05-01

Coral reefs, among the world's most biodiverse and productive submerged habitats, have faced several mass bleaching events due to climate change during the past 35 years. In the course of this century, global warming and ocean acidification are expected to cause corals to become increasingly rare on reef systems. This will result in a sharp decrease in the biodiversity of reef communities and carbonate reef structures. Coral reefs may be mapped, characterized and monitored through remote sensing. Hyperspectral images in particular excel in being used in coral monitoring, being characterized by very rich spectral information, which results in a strong discrimination power to characterize a target of interest, and separate healthy corals from bleached ones. Being submerged habitats, coral reef systems are difficult to analyse in airborne or satellite images, as relevant information is conveyed in bands in the blue range which exhibit lower signal-to-noise ratio (SNR) with respect to other spectral ranges; furthermore, water is absorbing most of the incident solar radiation, further decreasing the SNR. Derivative features, which are important in coral analysis, result greatly affected by the resulting noise present in relevant spectral bands, justifying the need of new denoising techniques able to keep local spatial and spectral features. In this paper, Unmixing-based Denoising (UBD) is used to enable analysis of a hyperspectral image acquired over a coral reef system in the Red Sea based on derivative features. UBD reconstructs pixelwise a dataset with reduced noise effects, by forcing each spectrum to a linear combination of other reference spectra, exploiting the high dimensionality of hyperspectral datasets. Results show clear enhancements with respect to traditional denoising methods based on spatial and spectral smoothing, facilitating the coral detection task.

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.

Reef structure drives parrotfish species composition on shelf edge reefs in La Parguera, Puerto Rico

NASA Astrophysics Data System (ADS)

Tzadik, Orian E.; Appeldoorn, Richard S.

2013-02-01

Shelf edge reefs that exist in coral reef ecosystems provide essential habitats for a large variety of fish and other marine organisms. Marine herbivores act as differential algal grazers that advocate coral reef colonization. In the Caribbean basin parrotfishes make up a large contingency of such herbivores and act as important ecological ichthyofauna. By investigating parrotfish relationship with habitat, this study aims to aid in future predictive mapping techniques that will outline parrotfish distributions via benthic quantification. Parrotfish communities were evaluated on the shelf edge reef off of La Parguera, Puerto Rico. Parrotfish abundances were found to positively correlate with high values of overall reef structure. High values of coral cover and of rugosity were strong indicators of most parrotfish species. The lone exception, Scarus taeniopterus, negatively correlated with these factors and positively correlated with algal cover. Indications exist that Scarus taeniopterus and Scarus iseri are sympatric species and can be found in abundance at opposite locations.

A relic coral fauna threatened by global changes and human activities, Eastern Brazil.

PubMed

Leão, Zelinda M A N; Kikuchi, Ruy K P

2005-01-01

Coral species composition of drilled cores from emergent bank reefs, and coral cover of the surface of old and living reefs located along the coast of the state of Bahia, Eastern Brazil, revealed that there is a marked change in the occurrence of the major building coral species in different time intervals of the reef structure, as well as in the living surface of reefs located in two different geographical sites. Holocene core sections from two reef areas (12 degrees 40'S-38 degrees 00'W and 18 degrees 00'S-39 degrees 00'W) have as major reef builders, on its topmost core interval (3 to 4 ky old), the endemic coral Mussismilia braziliensis Verrill, 1868, which also dominate on the 2.5-3.5 ky old surfaces of truncated reef tops. At the base of the cores (the 2m lower interval, older than 4 ky BP), another endemic coral Mussismilia harttii Verrill, 1868 is the dominant reef component. The relative abundance of M. braziliensis on the living surfaces of shallow reefs from both areas, shows that in the southern area, it is up to 98% on reefs located 60 km off the coast, in depths between 3 and 4m, but do not exceed 1.3% on the surface of the northern reefs located 1-2 km off the coast in depths 4-5m. The Holocene falling sea level that occurred along the coast of Brazil since 5.1 ky BP, causes an increasing runoff into the area of coastal reefs. This phenomenon may have affected the nearshore reef building fauna, replacing a more susceptive coral fauna with one better adapted to low light levels and higher sediment influx. The high turbidity associated with early Holocene shelf flooding, should also be responsible for the absence of M. braziliensis during the initial stages of reef buildup in Brazil. At the present time, the rapidly increasing human pressure, due to changes in land uses of the coastal zone (increasing sedimentation rate, nutrification of coastal waters, industrial pollution) and underwater practices, such as overfishing and an intense tourism, is aggravating the recovery capacity of this already naturally threatened coral community. If this situation coupled with increasing sea surface temperature persists, modern coral reef growth, in Brazil cannot be maintained and the major reef building coral species of the reefs in Bahia, a remnant endemic coral fauna will very soon appear in the list of endangered species.

Recovery of coral cover in records spanning 44 yr for reefs in Kāne`ohe Bay, Oa`hu, Hawai`i

NASA Astrophysics Data System (ADS)

Stimson, John

2018-03-01

Published and unpublished long-term studies are assembled to examine trends in coral cover and the dependence of change in coral cover on the initial coral cover in Kāne`ohe Bay over the last 44 yr. Each study showed there had been periods of increase in coral cover in the bay and showed that the rate of change in cover has been inversely dependent on the initial cover at a site. When coral cover is high on upper reef slopes, the fragile structure of reefs in this sheltered bay often collapses, resulting in a decrease in coral cover. The rate of change in coral cover was also inversely dependent on cover in one of the two studies that included analysis of reef-flat corals; the cause of decrease in cover in this habitat is thought to be attributable to particularly low sea levels in Hawai`i in the late 1990s and 2009-2010. The inverse relationship between initial coral cover and change in cover, and the intersections of the regression lines of these variables with the x-axis at intermediate values of coral cover, is indicative of resilience in this ecosystem over the last 44 yr. In the 1970s, the invasive macroscopic green alga Dictyosphaeria cavernosa covered a high percentage of coral habitat and commonly displaced corals from the reef slope and outer reef flats; the change was cited as an example of a phase shift on a reef. This alga has virtually disappeared from the bay, thus increasing the space available to corals; its disappearance is coincident with the increase in coral cover. Other species of macroalgae, including alien species, have not replaced D. cavernosa as major space competitors. The increase in coral cover and virtual disappearance of D. cavernosa constitute an example of a phase-shift reversal.

Coral assemblages are structured along a turbidity gradient on the Southwestern Gulf of Mexico, Veracruz

NASA Astrophysics Data System (ADS)

Jordán-Garza, A. G.; González-Gándara, C.; Salas-Pérez, J. J.; Morales-Barragan, A. M.

2017-04-01

Corals on the reef corridor of the southwestern Gulf of Mexico have evolved on a terrigenous shallow continental shelf under the influence of several natural river systems. As a result, water turbidity on these reefs can be high, with visibility as low as <1 m, depending on reef location and season. Using a presence-absence species database from field surveys, literature search, and satellite data on sea surface temperature, turbidity and chlorophyll-a, the coral species composition and environmental variables were analyzed for the three main reef systems of the reef corridor of the southwestern Gulf of Mexico. Completeness of the data set was assessed using species accumulation curves and non-parametric estimators of species richness. Differences in coral assemblages' composition between the reef systems were investigated using univariate (ANOVA) and multivariate (nMDS, ANOSIM, SIMPER) analyses and the relationship between the assemblages and environmental data was assessed using a forward selection process in canonical correspondence analysis (CCA) to eliminate non-significant environmental variables. The northern and central Veracruz reef systems share a similar number of coral species (p=0.78 mult. comp.) and both showed higher species richness than the southern system (p<0.001 mult. comp.). In terms of the assemblages' structure, significant differences were found (ANOSIM R=0.3, p=0.001) with larger average dissimilitude between north-south (75.4% SIMPER) and central-south (74.2%) than north-central (27%) comparisons. Only environmental variables related to water turbidity and productivity were significant on the final CCA configuration, which showed a gradient of increasing turbidity from north to south. Reef geomorphology and the effect of turbidity help explain differences in coral assemblages' composition. More studies are necessary to establish if turbidity could function as a refuge for future environmental stress. Each Veracruz reef system is at the same time unique and shares a pool of coral species. To protect these ecosystems it is necessary to effectively manage water quality and consider coral diversity on the reef corridor of the southwestern Gulf of Mexico.

Recruitment, mortality, and resilience potential of scleractinian corals at Eilat, Red Sea

NASA Astrophysics Data System (ADS)

Shlesinger, Tom; Loya, Yossi

2016-12-01

Events of mass coral bleaching and mortality have increased in recent decades worldwide, making coral recruitment more important than ever in sustaining coral-reef ecosystems and ensuring their resilience. During the last four decades, the coral reefs of Eilat have undergone severe deterioration due to both anthropogenic and natural causes. Recruitment failure has been frequently suggested as one of the main mechanisms underlying this deterioration. Here we assess the demographic replenishment and resilience potential of the local reefs, i.e., the potential for new sexually derived corals to recruit and exceed the community's mortality rate. We present a detailed analysis of coral community demography, obtained by means of high-resolution photographic monitoring of permanently marked plots. Coral spats as small as 1 mm were documented and the detailed dynamics of coral recruitment and mortality were recorded, in addition to other common ecological measurements. The cumulative quantity of recruited individuals was twofold to fivefold higher than total mortality. The most significant predictor variable for coral recruitment among all ecological parameters measured was the available substrate for settlement, and the survival of recruited corals was correlated with reef structural complexity. Two consecutive annual reproductive seasons (June-September of each year) with high recruitment rates were monitored. Combined with the high survival of recruits and the increase in coral live cover and abundance, the findings from this study indicate an encouraging potential for recovery of these reefs.

Simple ecological trade-offs give rise to emergent cross-ecosystem distributions of a coral reef fish.

PubMed

Grol, Monique G G; Nagelkerken, Ivan; Rypel, Andrew L; Layman, Craig A

2011-01-01

Ecosystems are intricately linked by the flow of organisms across their boundaries, and such connectivity can be essential to the structure and function of the linked ecosystems. For example, many coral reef fish populations are maintained by the movement of individuals from spatially segregated juvenile habitats (i.e., nurseries, such as mangroves and seagrass beds) to areas preferred by adults. It is presumed that nursery habitats provide for faster growth (higher food availability) and/or low predation risk for juveniles, but empirical data supporting this hypothesis is surprisingly lacking for coral reef fishes. Here, we investigate potential mechanisms (growth, predation risk, and reproductive investment) that give rise to the distribution patterns of a common Caribbean reef fish species, Haemulon flavolineatum (French grunt). Adults were primarily found on coral reefs, whereas juvenile fish only occurred in non-reef habitats. Contrary to our initial expectations, analysis of length-at-age revealed that growth rates were highest on coral reefs and not within nursery habitats. Survival rates in tethering trials were 0% for small juvenile fish transplanted to coral reefs and 24-47% in the nurseries. As fish grew, survival rates on coral reefs approached those in non-reef habitats (56 vs. 77-100%, respectively). As such, predation seems to be the primary factor driving across-ecosystem distributions of this fish, and thus the primary reason why mangrove and seagrass habitats function as nursery habitat. Identifying the mechanisms that lead to such distributions is critical to develop appropriate conservation initiatives, identify essential fish habitat, and predict impacts associated with environmental change.

Simple ecological trade-offs give rise to emergent cross-ecosystem distributions of a coral reef fish

PubMed Central

Grol, Monique G. G.; Rypel, Andrew L.; Layman, Craig A.

2010-01-01

Ecosystems are intricately linked by the flow of organisms across their boundaries, and such connectivity can be essential to the structure and function of the linked ecosystems. For example, many coral reef fish populations are maintained by the movement of individuals from spatially segregated juvenile habitats (i.e., nurseries, such as mangroves and seagrass beds) to areas preferred by adults. It is presumed that nursery habitats provide for faster growth (higher food availability) and/or low predation risk for juveniles, but empirical data supporting this hypothesis is surprisingly lacking for coral reef fishes. Here, we investigate potential mechanisms (growth, predation risk, and reproductive investment) that give rise to the distribution patterns of a common Caribbean reef fish species, Haemulon flavolineatum (French grunt). Adults were primarily found on coral reefs, whereas juvenile fish only occurred in non-reef habitats. Contrary to our initial expectations, analysis of length-at-age revealed that growth rates were highest on coral reefs and not within nursery habitats. Survival rates in tethering trials were 0% for small juvenile fish transplanted to coral reefs and 24–47% in the nurseries. As fish grew, survival rates on coral reefs approached those in non-reef habitats (56 vs. 77–100%, respectively). As such, predation seems to be the primary factor driving across-ecosystem distributions of this fish, and thus the primary reason why mangrove and seagrass habitats function as nursery habitat. Identifying the mechanisms that lead to such distributions is critical to develop appropriate conservation initiatives, identify essential fish habitat, and predict impacts associated with environmental change. PMID:21072542

Baselines and Degradation of Coral Reefs in the Northern Line Islands

PubMed Central

Sandin, Stuart A.; Smith, Jennifer E.; DeMartini, Edward E.; Dinsdale, Elizabeth A.; Donner, Simon D.; Friedlander, Alan M.; Konotchick, Talina; Malay, Machel; Maragos, James E.; Obura, David; Pantos, Olga; Paulay, Gustav; Richie, Morgan; Rohwer, Forest; Schroeder, Robert E.; Walsh, Sheila; Jackson, Jeremy B. C.; Knowlton, Nancy; Sala, Enric

2008-01-01

Effective conservation requires rigorous baselines of pristine conditions to assess the impacts of human activities and to evaluate the efficacy of management. Most coral reefs are moderately to severely degraded by local human activities such as fishing and pollution as well as global change, hence it is difficult to separate local from global effects. To this end, we surveyed coral reefs on uninhabited atolls in the northern Line Islands to provide a baseline of reef community structure, and on increasingly populated atolls to document changes associated with human activities. We found that top predators and reef-building organisms dominated unpopulated Kingman and Palmyra, while small planktivorous fishes and fleshy algae dominated the populated atolls of Tabuaeran and Kiritimati. Sharks and other top predators overwhelmed the fish assemblages on Kingman and Palmyra so that the biomass pyramid was inverted (top-heavy). In contrast, the biomass pyramid at Tabuaeran and Kiritimati exhibited the typical bottom-heavy pattern. Reefs without people exhibited less coral disease and greater coral recruitment relative to more inhabited reefs. Thus, protection from overfishing and pollution appears to increase the resilience of reef ecosystems to the effects of global warming. PMID:18301734

Morphological plasticity of the depth generalist coral, Montastraea cavernosa, on mesophotic reefs in Bermuda.

PubMed

Goodbody-Gringley, Gretchen; Waletich, Justin

2018-04-02

Scleractinian corals have global ecological, structural, social, and economic importance that is disproportionately large relative to their areal extent. These reef building corals form the architectural framework for shallow water tropical reef systems, supporting the most productive and biologically diverse marine ecosystems on Earth (Veron, 1995). Reef-building scleractinian species are dependent on photosynthetic products supplied by symbiotic zooxanthellae of the genus Symbiodinium, restricting their distribution to the photic zone (Stambler, 2011). This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

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.

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

PubMed

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

2016-09-01

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

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

PubMed

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

2013-01-01

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

Sponge Communities on Caribbean Coral Reefs Are Structured by Factors That Are Top-Down, Not Bottom-Up

PubMed Central

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

2013-01-01

Caribbean coral reefs have been transformed in the past few decades with the demise of reef-building corals, and sponges are now the dominant habitat-forming organisms on most reefs. Competing hypotheses propose that sponge communities are controlled primarily by predatory fishes (top-down) or by the availability of picoplankton to suspension-feeding sponges (bottom-up). We tested these hypotheses on Conch Reef, off Key Largo, Florida, by placing sponges inside and outside predator-excluding cages at sites with less and more planktonic food availability (15 m vs. 30 m depth). There was no evidence of a bottom-up effect on the growth of any of 5 sponge species, and 2 of 5 species grew more when caged at the shallow site with lower food abundance. There was, however, a strong effect of predation by fishes on sponge species that lacked chemical defenses. Sponges with chemical defenses grew slower than undefended species, demonstrating a resource trade-off between growth and the production of secondary metabolites. Surveys of the benthic community on Conch Reef similarly did not support a bottom-up effect, with higher sponge cover at the shallower depth. We conclude that the structure of sponge communities on Caribbean coral reefs is primarily top-down, and predict that removal of sponge predators by overfishing will shift communities toward faster-growing, undefended species that better compete for space with threatened reef-building corals. PMID:23667492

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bottlenecks to coral recovery in the Seychelles

NASA Astrophysics Data System (ADS)

Chong-Seng, K. M.; Graham, N. A. J.; Pratchett, M. S.

2014-06-01

Processes that affect recovery of coral assemblages require investigation because coral reefs are experiencing a diverse array of more frequent disturbances. Potential bottlenecks to coral recovery include limited larval supply, low rates of settlement, and high mortality of new recruits or juvenile corals. We investigated spatial variation in local abundance of scleractinian corals in the Seychelles at three distinct life history stages (recruits, juveniles, and adults) on reefs with differing benthic conditions. Following widespread coral loss due to the 1998 bleaching event, some reefs are recovering (i.e., relatively high scleractinian coral cover: `coral-dominated'), some reefs have low cover of living macrobenthos and unconsolidated rubble substrates (`rubble-dominated'), and some reefs have high cover of macroalgae (`macroalgal-dominated'). Rates of coral recruitment to artificial settlement tiles were similar across all reef conditions, suggesting that larval supply does not explain differential coral recovery across the three reef types. However, acroporid recruits were absent on macroalgal-dominated reefs (0.0 ± 0.0 recruits tile-1) in comparison to coral-dominated reefs (5.2 ± 1.6 recruits tile-1). Juvenile coral colony density was significantly lower on macroalgal-dominated reefs (2.4 ± 1.1 colonies m-2), compared to coral-dominated reefs (16.8 ± 2.4 m-2) and rubble-dominated reefs (33.1 ± 7.3 m-2), suggesting that macroalgal-dominated reefs have either a bottleneck to successful settlement on the natural substrates or a high post-settlement mortality bottleneck. Rubble-dominated reefs had very low cover of adult corals (10.0 ± 1.7 %) compared to coral-dominated reefs (33.4 ± 3.6 %) despite no statistical difference in their juvenile coral densities. A bottleneck caused by low juvenile colony survivorship on unconsolidated rubble-dominated reefs is possible, or alternatively, recruitment to rubble-dominated reefs has only recently begun. This study identified bottlenecks to recovery of coral assemblages that varied depending on post-disturbance habitat condition.

Local and Regional Impacts of Pollution on Coral Reefs along the Thousand Islands North of the Megacity Jakarta, Indonesia.

PubMed

Baum, Gunilla; Januar, Hedi I; Ferse, Sebastian C A; Kunzmann, Andreas

2015-01-01

Worldwide, coral reefs are challenged by multiple stressors due to growing urbanization, industrialization and coastal development. Coral reefs along the Thousand Islands off Jakarta, one of the largest megacities worldwide, have degraded dramatically over recent decades. The shift and decline in coral cover and composition has been extensively studied with a focus on large-scale gradients (i.e. regional drivers), however special focus on local drivers in shaping spatial community composition is still lacking. Here, the spatial impact of anthropogenic stressors on local and regional scales on coral reefs north of Jakarta was investigated. Results indicate that the direct impact of Jakarta is mainly restricted to inshore reefs, separating reefs in Jakarta Bay from reefs along the Thousand Islands further north. A spatial patchwork of differentially degraded reefs is present along the islands as a result of localized anthropogenic effects rather than regional gradients. Pollution is the main anthropogenic stressor, with over 80% of variation in benthic community composition driven by sedimentation rate, NO2, PO4 and Chlorophyll a. Thus, the spatial structure of reefs is directly related to intense anthropogenic pressure from local as well as regional sources. Therefore, improved spatial management that accounts for both local and regional stressors is needed for effective marine conservation.

Local and Regional Impacts of Pollution on Coral Reefs along the Thousand Islands North of the Megacity Jakarta, Indonesia

PubMed Central

Baum, Gunilla; Januar, Hedi I.; Ferse, Sebastian C. A.; Kunzmann, Andreas

2015-01-01

Worldwide, coral reefs are challenged by multiple stressors due to growing urbanization, industrialization and coastal development. Coral reefs along the Thousand Islands off Jakarta, one of the largest megacities worldwide, have degraded dramatically over recent decades. The shift and decline in coral cover and composition has been extensively studied with a focus on large-scale gradients (i.e. regional drivers), however special focus on local drivers in shaping spatial community composition is still lacking. Here, the spatial impact of anthropogenic stressors on local and regional scales on coral reefs north of Jakarta was investigated. Results indicate that the direct impact of Jakarta is mainly restricted to inshore reefs, separating reefs in Jakarta Bay from reefs along the Thousand Islands further north. A spatial patchwork of differentially degraded reefs is present along the islands as a result of localized anthropogenic effects rather than regional gradients. Pollution is the main anthropogenic stressor, with over 80% of variation in benthic community composition driven by sedimentation rate, NO2, PO4 and Chlorophyll a. Thus, the spatial structure of reefs is directly related to intense anthropogenic pressure from local as well as regional sources. Therefore, improved spatial management that accounts for both local and regional stressors is needed for effective marine conservation. PMID:26378910

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

Tropical fishes dominate temperate reef fish communities within western Japan.

PubMed

Nakamura, Yohei; Feary, David A; Kanda, Masaru; Yamaoka, Kosaku

2013-01-01

Climate change is resulting in rapid poleward shifts in the geographical distribution of tropical and subtropical fish species. We can expect that such range shifts are likely to be limited by species-specific resource requirements, with temperate rocky reefs potentially lacking a range of settlement substrates or specific dietary components important in structuring the settlement and success of tropical and subtropical fish species. We examined the importance of resource use in structuring the distribution patterns of range shifting tropical and subtropical fishes, comparing this with resident temperate fish species within western Japan (Tosa Bay); the abundance, diversity, size class, functional structure and latitudinal range of reef fishes utilizing both coral reef and adjacent rocky reef habitat were quantified over a 2 year period (2008-2010). This region has undergone rapid poleward expansion of reef-building corals in response to increasing coastal water temperatures, and forms one of the global hotspots for rapid coastal changes. Despite the temperate latitude surveyed (33°N, 133°E) the fish assemblage was both numerically, and in terms of richness, dominated by tropical fishes. Such tropical faunal dominance was apparent within both coral, and rocky reef habitats. The size structure of the assemblage suggested that a relatively large number of tropical species are overwintering within both coral and rocky habitats, with a subset of these species being potentially reproductively active. The relatively high abundance and richness of tropical species with obligate associations with live coral resources (i.e., obligate corallivores) shows that this region holds the most well developed temperate-located tropical fish fauna globally. We argue that future tropicalisation of the fish fauna in western Japan, associated with increasing coral habitat development and reported increasing shifts in coastal water temperatures, may have considerable positive economic impacts to the local tourism industry and bring qualitative changes to both local and regional fisheries resources.

Tropical Fishes Dominate Temperate Reef Fish Communities within Western Japan

PubMed Central

Nakamura, Yohei; Feary, David A.; Kanda, Masaru; Yamaoka, Kosaku

2013-01-01

Climate change is resulting in rapid poleward shifts in the geographical distribution of tropical and subtropical fish species. We can expect that such range shifts are likely to be limited by species-specific resource requirements, with temperate rocky reefs potentially lacking a range of settlement substrates or specific dietary components important in structuring the settlement and success of tropical and subtropical fish species. We examined the importance of resource use in structuring the distribution patterns of range shifting tropical and subtropical fishes, comparing this with resident temperate fish species within western Japan (Tosa Bay); the abundance, diversity, size class, functional structure and latitudinal range of reef fishes utilizing both coral reef and adjacent rocky reef habitat were quantified over a 2 year period (2008–2010). This region has undergone rapid poleward expansion of reef-building corals in response to increasing coastal water temperatures, and forms one of the global hotspots for rapid coastal changes. Despite the temperate latitude surveyed (33°N, 133°E) the fish assemblage was both numerically, and in terms of richness, dominated by tropical fishes. Such tropical faunal dominance was apparent within both coral, and rocky reef habitats. The size structure of the assemblage suggested that a relatively large number of tropical species are overwintering within both coral and rocky habitats, with a subset of these species being potentially reproductively active. The relatively high abundance and richness of tropical species with obligate associations with live coral resources (i.e., obligate corallivores) shows that this region holds the most well developed temperate-located tropical fish fauna globally. We argue that future tropicalisation of the fish fauna in western Japan, associated with increasing coral habitat development and reported increasing shifts in coastal water temperatures, may have considerable positive economic impacts to the local tourism industry and bring qualitative changes to both local and regional fisheries resources. PMID:24312528

The future of coral reefs in the US Virgin Islands: is Acropora palmata more likely to recover than Montastraea annularis complex?

USGS Publications Warehouse

Rogers, Caroline S.; Muller, Erinn; Spitzack, Tony; Miller, Jeff

2008-01-01

Coral diseases have played a major role in the degradation of coral reefs in the Caribbean, including those in the US Virgin Islands (USVI). In 2005, bleaching affected reefs throughout the Caribbean, and was especially severe on USVI reefs. Some corals began to regain their color as water temperatures cooled, but an outbreak of disease (primarily white plague) led to losses of over 60% of the total live coral cover. Montastraea annularis, the most abundant coral, was disproportionately affected, and decreased in relative abundance. The threatened species Acropora palmata bleached for the first time on record in the USVI but suffered less bleaching and less mortality from disease than M. annularis. Acropora palmata and M. annularis are the two most significant species in the USVI because of their structural role in the architecture of the reefs, the large size of their colonies, and their complex morphology. The future of the USVI reefs depends largely on their fate. Acropora palmata is more likely to recover than M. annularis for many reasons, including its faster growth rate, and its lower vulnerability to bleaching and disease.

Environmental Records from Great Barrier Reef Corals: Inshore versus Offshore Drivers

PubMed Central

Walther, Benjamin D.; Kingsford, Michael J.; McCulloch, Malcolm T.

2013-01-01

The biogenic structures of stationary organisms can be effective recorders of environmental fluctuations. These proxy records of environmental change are preserved as geochemical signals in the carbonate skeletons of scleractinian corals and are useful for reconstructions of temporal and spatial fluctuations in the physical and chemical environments of coral reef ecosystems, including The Great Barrier Reef (GBR). We compared multi-year monitoring of water temperature and dissolved elements with analyses of chemical proxies recorded in Porites coral skeletons to identify the divergent mechanisms driving environmental variation at inshore versus offshore reefs. At inshore reefs, water Ba/Ca increased with the onset of monsoonal rains each year, indicating a dominant control of flooding on inshore ambient chemistry. Inshore multi-decadal records of coral Ba/Ca were also highly periodic in response to flood-driven pulses of terrigenous material. In contrast, an offshore reef at the edge of the continental shelf was subject to annual upwelling of waters that were presumed to be richer in Ba during summer months. Regular pulses of deep cold water were delivered to the reef as indicated by in situ temperature loggers and coral Ba/Ca. Our results indicate that although much of the GBR is subject to periodic environmental fluctuations, the mechanisms driving variation depend on proximity to the coast. Inshore reefs are primarily influenced by variable freshwater delivery and terrigenous erosion of catchments, while offshore reefs are dominated by seasonal and inter-annual variations in oceanographic conditions that influence the propensity for upwelling. The careful choice of sites can help distinguish between the various factors that promote Ba uptake in corals and therefore increase the utility of corals as monitors of spatial and temporal variation in environmental conditions. PMID:24204743

Conservation of coral reefs through active restoration measures: recent approaches and last decade progress.

PubMed

Rinkevich, Baruch

2005-06-15

The scientific discipline of active restoration of denuded coral reef areas has drawn much attention in the past decade as it became evident that this ecosystem does not often recover naturally from anthropogenic stress without manipulation. Essentially, the choices are eitherthe continuous degradation of the reefs or active restoration to encourage reef development. As a result, worldwide restoration operations during the past decade have been recognized as being a major tool for reef rehabilitation. This situation has also stirred discussions and debates on the various restoration measures suggested as management options, supplementary to the traditional conservation acts. The present essay reviews past decade's (1994-2004) approaches and advances in coral reef restoration. While direct coral transplantation is still the primer vehicle of operations used, the concept of in situ and ex situ coral nurseries (the gardening concept), where coral materials (nubbins, branches, spats) are maricultured to a size suitable for transplantation, has been gaining recognition. The use of nubbins (down to the size of a single or few polyps) has been suggested and employed as a unique technique for mass production of coral colonies. Restoration of ship grounding sites and the use of artificial reefs have become common tools for specific restoration needs. Substrate stabilization, 3-D structural consideration of developing colonies, and the use of molecular/biochemical tools are part of novel technology approaches developed in the past decade. Economic considerations for reef restoration have become an important avenue for evaluating success of restoration activities. It has been suggested that landscape restoration and restoration genetics are important issues to be studied. In the future, as coral reef restoration may become the dominant conservation act, there would be the need not only to develop improved protocols but also to define the conceptual bases.

Influence of Eunice norvegica on feeding and calcification in the coral Lophelia pertusa

NASA Astrophysics Data System (ADS)

Mueller, C. E.; van Oevelen, D.; Middelburg, J. J.; Lundälv, T.

2012-04-01

Lophelia pertusa is the main framework building cold-water coral in the North Atlantic. It forms complex reef structures, extending up to several km in length and several meters in hight. Many species are attracted by the coral frame work, forming a highly diverse community within the reef. Although most work has focused on the corals, the functioning of the system also depends on interactions between corals and associated species. A particular example is the Polychaete Eunice norvegica that lives in close association with the coral host. The Polychaete builds a thin texture-tube between living coral branches and stimulates the coral to calcify the tube. This process strengthens the reef framwork by thickening and connecting coral brances and thereby acts as a positive feedback on the development of large reef structures. This comes however at an metabolic cost for the coral due to the enhanced calcificationrates. Another negative feedback for cold-water coral may be food related, since aquaria observations have shown that Eunice occasionally steels food from its host coral. In this study we investigated the interactions between the coral and polychaete related to calcification and food partitioning for two food types (algae and Artemia). The uptake of 13C and 15N labeled food sources by the worm and the coral was studied in chambers with only corals, only the polychaete and both species present. After 7 days, corals and worms were analyzed for isotope incorporation in bulk tissue and skeleton samples and specific fatty acids (13C) using GC-c-IRMS (gas-chromatography-combustion-isotope ratio mass spectrometry). Corals that were kept in the presence of Eunice indeed showed a higher calcification rates of 7.4 ug C (day* g dw coral)-1, evidencing the stimulation of calcification by Eunice. Interestingly, food uptake of algae and Artemia was higher in the coral-worm treatment for both species as compared to the single species treatments. These results shed new light on trophic and non-trophic interactions in cold-water coral reefs.

Volcanic Acidification of a Coral Reef at Maug Island: Influences on Biological Processes and Ecosystem Structure

NASA Astrophysics Data System (ADS)

Enochs, I.; Manzello, D.; Donham, E. M.; Johnston, L.; Valentino, L.; Young, C.; Kolodziej, G.; Carlton, R.; Price, N.

2016-02-01

Coral reef ecosystems are expected to be strongly impacted by ocean acidification (OA) in the coming century. The influences of OA on coral reefs will be numerous, involving diverse species with different degrees of susceptibility. Naturally acidified systems provide a way to study these individual responses and a means to investigate how myriad alterations manifest at the ecosystem-scale over long periods of time. To this end, we characterized the unique coral reef ecosystem surrounding the volcanic carbon dioxide vent at Maug Island in the Commonwealth of the Northern Mariana Islands (CNMI). We present data on the spatial extent of carbonate chemistry alteration through interpolation of water bottle samples, and data on the temporal nature of this gradient through the deployment of three SeaFET pH loggers over a period of three months. We analyze trace-gas concentrations and characterize fluctuations in light, current, tides, and temperature. We tie these environmental data to high-resolution photo mosaics and in situ biodiversity surveys to examine changes in reef community structure correlated with this natural OA gradient. Finally, we investigate the influence of vent proximity on biological processes affecting reef habitat growth and erosion. Using computed tomography (CT) and analysis of coral growth bands, we analyze changes in the calcification of massive Porites coral. Using crystalline calcium carbonate (calcite) blocks, we quantify the settlement and erosion rate of microboring algae. Together these measurements underscore the strong influence that OA will have on reef persistence and highlight the value of the Maug site for future OA research.

Climate-Smart Design for Ecosystem Management: A Test Application for Coral Reefs.

PubMed

West, Jordan M; Courtney, Catherine A; Hamilton, Anna T; Parker, Britt A; Julius, Susan H; Hoffman, Jennie; Koltes, Karen H; MacGowan, Petra

2017-01-01

The interactive and cumulative impacts of climate change on natural resources such as coral reefs present numerous challenges for conservation planning and management. Climate change adaptation is complex due to climate-stressor interactions across multiple spatial and temporal scales. This leaves decision makers worldwide faced with local, regional, and global-scale threats to ecosystem processes and services, occurring over time frames that require both near-term and long-term planning. Thus there is a need for structured approaches to adaptation planning that integrate existing methods for vulnerability assessment with design and evaluation of effective adaptation responses. The Corals and Climate Adaptation Planning project of the U.S. Coral Reef Task Force seeks to develop guidance for improving coral reef management through tailored application of a climate-smart approach. This approach is based on principles from a recently-published guide which provides a framework for adopting forward-looking goals, based on assessing vulnerabilities to climate change and applying a structured process to design effective adaptation strategies. Work presented in this paper includes: (1) examination of the climate-smart management cycle as it relates to coral reefs; (2) a compilation of adaptation strategies for coral reefs drawn from a comprehensive review of the literature; (3) in-depth demonstration of climate-smart design for place-based crafting of robust adaptation actions; and (4) feedback from stakeholders on the perceived usefulness of the approach. We conclude with a discussion of lessons-learned on integrating climate-smart design into real-world management planning processes and a call from stakeholders for an "adaptation design tool" that is now under development.

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…

Trophic cascade facilitates coral recruitment in a marine reserve

PubMed Central

Mumby, Peter J.; Harborne, Alastair R.; Williams, Jodene; Kappel, Carrie V.; Brumbaugh, Daniel R.; Micheli, Fiorenza; Holmes, Katherine E.; Dahlgren, Craig P.; Paris, Claire B.; Blackwell, Paul G.

2007-01-01

Reduced fishing pressure and weak predator–prey interactions within marine reserves can create trophic cascades that increase the number of grazing fishes and reduce the coverage of macroalgae on coral reefs. Here, we show that the impacts of reserves extend beyond trophic cascades and enhance the process of coral recruitment. Increased fish grazing, primarily driven by reduced fishing, was strongly negatively correlated with macroalgal cover and resulted in a 2-fold increase in the density of coral recruits within a Bahamian reef system. Our conclusions are robust because four alternative hypotheses that may generate a spurious correlation between grazing and coral recruitment were tested and rejected. Grazing appears to influence the density and community structure of coral recruits, but no detectable influence was found on the overall size-frequency distribution, community structure, or cover of corals. We interpret this absence of pattern in the adult coral community as symptomatic of the impact of a recent disturbance event that masks the recovery trajectories of individual reefs. Marine reserves are not a panacea for conservation but can facilitate the recovery of corals from disturbance and may help sustain the biodiversity of organisms that depend on a complex three-dimensional coral habitat. PMID:17488824

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

2017-05-01

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.

Deep reefs are not universal refuges: Reseeding potential varies among coral species

PubMed Central

Bongaerts, Pim; Riginos, Cynthia; Brunner, Ramona; Englebert, Norbert; Smith, Struan R.; Hoegh-Guldberg, Ove

2017-01-01

Deep coral reefs (that is, mesophotic coral ecosystems) can act as refuges against major disturbances affecting shallow reefs. It has been proposed that, through the provision of coral propagules, such deep refuges may aid in shallow reef recovery; however, this “reseeding” hypothesis remains largely untested. We conducted a genome-wide assessment of two scleractinian coral species with contrasting reproductive modes, to assess the potential for connectivity between mesophotic (40 m) and shallow (12 m) depths on an isolated reef system in the Western Atlantic (Bermuda). To overcome the pervasive issue of endosymbiont contamination associated with de novo sequencing of corals, we used a novel subtraction reference approach. We have demonstrated that strong depth-associated selection has led to genome-wide divergence in the brooding species Agaricia fragilis (with divergence by depth exceeding divergence by location). Despite introgression from shallow into deep populations, a lack of first-generation migrants indicates that effective connectivity over ecological time scales is extremely limited for this species and thus precludes reseeding of shallow reefs from deep refuges. In contrast, no genetic structuring between depths (or locations) was observed for the broadcasting species Stephanocoenia intersepta, indicating substantial potential for vertical connectivity. Our findings demonstrate that vertical connectivity within the same reef system can differ greatly between species and that the reseeding potential of deep reefs in Bermuda may apply to only a small number of scleractinian species. Overall, we argue that the “deep reef refuge hypothesis” holds for individual coral species during episodic disturbances but should not be assumed as a broader ecosystem-wide phenomenon. PMID:28246645

Thermal Consolidation of Dredge Sand for Artificial Reef Formations

NASA Astrophysics Data System (ADS)

Trevino, Alexandro

Coral Reef ecosystems have degraded over years due to a variety of environmental issues such as ocean acidification. The continuous stress has detrimental effects on coral reef ecosystems that can possibly lead to the loss of the ecosystem. Our research aims to construct a prototype of an artificial reef by consolidating dredge sand from the ship channels of South Texas. Consolidation is achieved through an aluminum polytetrafluoroethylene self-propagating high temperature process that yields a solid formation to mimic the physical properties of coral reef structures. Using thermodynamic calculations, the variation of initial components was determined that reached an adiabatic temperature with a maximum peak of 2000 K. The self-sustaining reaction front was obtained to rigidly consolidate the dredge sand only at composition concentrations exceeding a critical value of 24 wt.% Al, and 3 wt.% PTFE. The combustion synthesis produced a consolidated formation with a hardened and porous structure.

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…

Life on the edge: corals in mangroves and climate change

USGS Publications Warehouse

Rogers, Caroline S.; Herlan, James J.

2012-01-01

Coral diseases have played a major role in the degradation of coral reefs in the Caribbean, including those in the US Virgin Islands (USVI). In 2005, bleaching affected reefs throughout the Caribbean, and was especially severe on USVI reefs. Some corals began to regain their color as water temperatures cooled, but an outbreak of disease (primarily white plague) led to losses of over 60% of the total live coral cover. Montastraea annularis, the most abundant coral, was disproportionately affected, and decreased in relative abundance. The threatened species Acropora palmata bleached for the first time on record in the USVI but suffered less bleaching and less mortality from disease than M. annularis. Acropora palmata and M. annularis are the two most significant species in the USVI because of their structural role in the architecture of the reefs, the large size of their colonies, and their complex morphology. The future of the USVI reefs depends largely on their fate. Acropora palmata is more likely to recover than M. annularis for many reasons, including its faster growth rate, and its lower vulnerability to bleaching and disease.

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

PubMed Central

Barott, Katie L.; Rodriguez-Mueller, Beltran; Youle, Merry; Marhaver, Kristen L.; Vermeij, Mark J. A.; Smith, Jennifer E.; Rohwer, Forest L.

2012-01-01

Competition between reef-building corals and benthic algae is of key importance for reef dynamics. These interactions occur on many spatial scales, ranging from chemical to regional. Using microprobes, 16S rDNA pyrosequencing and underwater surveys, we examined the interactions between the reef-building coral Montastraea annularis and four types of benthic algae. The macroalgae Dictyota bartayresiana and Halimeda opuntia, as well as a mixed consortium of turf algae, caused hypoxia on the adjacent coral tissue. Turf algae were also associated with major shifts in the bacterial communities at the interaction zones, including more pathogens and virulence genes. In contrast to turf algae, interactions with crustose coralline algae (CCA) and M. annularis did not appear to be antagonistic at any scale. These zones were not hypoxic, the microbes were not pathogen-like and the abundance of coral–CCA interactions was positively correlated with per cent coral cover. We propose a model in which fleshy algae (i.e. some species of turf and fleshy macroalgae) alter benthic competition dynamics by stimulating bacterial respiration and promoting invasion of virulent bacteria on corals. This gives fleshy algae a competitive advantage over corals when human activities, such as overfishing and eutrophication, remove controls on algal abundance. Together, these results demonstrate the intricate connections and mechanisms that structure coral reefs. PMID:22090385

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.

Tropical dead zones and mass mortalities on coral reefs

PubMed Central

Altieri, Andrew H.; Harrison, Seamus B.; Seemann, Janina; Collin, Rachel; Diaz, Robert J.; Knowlton, Nancy

2017-01-01

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. PMID:28320966

Changes in coral-reef structure through the Miocene in the Mediterranean province: Adaptive versus environmental influence

NASA Astrophysics Data System (ADS)

Pomar, Luis; Hallock, Pamela

2007-10-01

Well-documented Mediterranean examples of Miocene carbonate platforms, with complete exposures from shallow-water to basinal facies, provide evidence for temporal changes in reef-building capacity of zooxanthellate corals. In pre-late Tortonian platforms, small coralgal patches and mounds occur from platform top to the toe of slope, but they did not build to sea level. In contrast, barrier reefs with unequivocal reef-crest structures that reached sea level are documented in late Tortonian-early Messinian platforms. We suggest that a change in both calcification rates and bathymetric zonation was the result of coevolution of corals and Symbiodinium zooxanthellae, coeval to global cooling and, at least at a regional scale, a geochemical change that supported widespread aragonite precipitation through the late Miocene.

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.

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.

Two ;pillars; of cold-water coral reefs along Atlantic European margins: Prevalent association of Madrepora oculata with Lophelia pertusa, from reef to colony scale

NASA Astrophysics Data System (ADS)

Arnaud-Haond, S.; Van den Beld, I. M. J.; Becheler, R.; Orejas, C.; Menot, L.; Frank, N.; Grehan, A.; Bourillet, J. F.

2017-11-01

The scleractinian coral Lophelia pertusa has been the focus of deep-sea research since the recognition of the vast extent of coral reefs in North Atlantic waters two decades ago, long after their existence was mentioned by fishermen. These reefs where shown to provide habitat, concentrate biomass and act as feeding or nursery grounds for many species, including those targeted by commercial fisheries. Thus, the attention given to this cold-water coral (CWC) species from researchers and the wider public has increased. Consequently, new research programs triggered research to determine the full extent of the corals geographic distribution and ecological dynamics of ;Lophelia reefs;. The present study is based on a systematic standardised sampling design to analyze the distribution and coverage of CWC reefs along European margins from the Bay of Biscay to Iceland. Based on Remotely Operated Vehicle (ROV) image analysis, we report an almost systematic occurrence of Madrepora oculata in association with L. pertusa with similar abundances of both species within explored reefs, despite a tendency of increased abundance of L. pertusa compared to M. oculata toward higher latitudes. This systematic association occasionally reached the colony scale, with ;twin; colonies of both species often observed growing next to each other when isolated structures were occurring off-reefs. Finally, several ;false chimaera; were observed within reefs, confirming that colonial structures can be ;coral bushes; formed by an accumulation of multiple colonies even at the inter-specific scale, with no need for self-recognition mechanisms. Thus, we underline the importance of the hitherto underexplored M. oculata in the Eastern Atlantic, re-establishing a more balanced view that both species and their yet unknown interactions are required to better elucidate the ecology, dynamics and fate of European CWC reefs in a changing environment.

Resilience of branching and massive corals to wave loading under sea level rise--a coupled computational fluid dynamics-structural analysis.

PubMed

Baldock, Tom E; Karampour, Hassan; Sleep, Rachael; Vyltla, Anisha; Albermani, Faris; Golshani, Aliasghar; Callaghan, David P; Roff, George; Mumby, Peter J

2014-09-15

Measurements of coral structural strength are coupled with a fluid dynamics-structural analysis to investigate the resilience of coral to wave loading under sea level rise and a typical Great Barrier Reef lagoon wave climate. The measured structural properties were used to determine the wave conditions and flow velocities that lead to structural failure. Hydrodynamic modelling was subsequently used to investigate the type of the bathymetry where coral is most vulnerable to breakage under cyclonic wave conditions, and how sea level rise (SLR) changes this vulnerability. Massive corals are determined not to be vulnerable to wave induced structural damage, whereas branching corals are susceptible at wave induced orbital velocities exceeding 0.5m/s. Model results from a large suite of idealised bathymetry suggest that SLR of 1m or a loss of skeleton strength of order 25% significantly increases the area of reef flat where branching corals are exposed to damaging wave induced flows. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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 help identify reef ecosystems most exposed to environmental stress as well as systems that may be more resistant or resilient to future climate change. PMID:23637939

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 identify reef ecosystems most exposed to environmental stress as well as systems that may be more resistant or resilient to future climate change.

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

PubMed Central

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

2012-01-01

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

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

PubMed

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

2012-01-01

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

Long-lived groupers require structurally stable reefs in the face of repeated climate change disturbances

NASA Astrophysics Data System (ADS)

Karkarey, R.; Kelkar, N.; Lobo, A. Savio; Alcoverro, T.; Arthur, R.

2014-06-01

Benthic recovery from climate-related disturbances does not always warrant a commensurate functional recovery for reef-associated fish communities. Here, we examine the distribution of benthic groupers (family Serranidae) in coral reef communities from the Lakshadweep archipelago (Arabian Sea) in response to structural complexity and long-term habitat stability. These coral reefs that have been subject to two major El Niño Southern Oscillation-related coral bleaching events in the last decades (1998 and 2010). First, we employ a long-term (12-yr) benthic-monitoring dataset to track habitat structural stability at twelve reef sites in the archipelago. Structural stability of reefs was strongly driven by exposure to monsoon storms and depth, which made deeper and more sheltered reefs on the eastern aspect more stable than the more exposed (western) and shallower reefs. We surveyed groupers (species richness, abundance, biomass) in 60 sites across the entire archipelago, representing both exposures and depths. Sites were selected along a gradient of structural complexity from very low to high. Grouper biomass appeared to vary with habitat stability with significant differences between depth and exposure; sheltered deep reefs had a higher grouper biomass than either sheltered shallow or exposed (deep and shallow) reefs. Species richness and abundance showed similar (though not significant) trends. More interestingly, average grouper biomass increased exponentially with structural complexity, but only at the sheltered deep (high stability) sites, despite the availability of recovered structure at exposed deep and shallow sites (lower-stability sites). This trend was especially pronounced for long-lived groupers (life span >10 yrs). These results suggest that long-lived groupers may prefer temporally stable reefs, independent of the local availability of habitat structure. In reefs subject to repeated disturbances, the presence of structurally stable reefs may be critical as refuges for functionally important, long-lived species like groupers.

75 FR 48934 - Coral Reef Conservation Program Implementation Guidelines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-12

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

Habitat dynamics, marine reserve status, and the decline and recovery of coral reef fish communities.

PubMed

Williamson, David H; Ceccarelli, Daniela M; Evans, Richard D; Jones, Geoffrey P; Russ, Garry R

2014-02-01

Severe climatic disturbance events often have major impacts on coral reef communities, generating cycles of decline and recovery, and in some extreme cases, community-level phase shifts from coral-to algal-dominated states. Benthic habitat changes directly affect reef fish communities, with low coral cover usually associated with low fish diversity and abundance. No-take marine reserves (NTRs) are widely advocated for conserving biodiversity and enhancing the sustainability of exploited fish populations. Numerous studies have documented positive ecological and socio-economic benefits of NTRs; however, the ability of NTRs to ameliorate the effects of acute disturbances on coral reefs has seldom been investigated. Here, we test these factors by tracking the dynamics of benthic and fish communities, including the important fishery species, coral trout (Plectropomus spp.), over 8 years in both NTRs and fished areas in the Keppel Island group, Great Barrier Reef, Australia. Two major disturbances impacted the reefs during the monitoring period, a coral bleaching event in 2006 and a freshwater flood plume in 2011. Both disturbances generated significant declines in coral cover and habitat complexity, with subsequent declines in fish abundance and diversity, and pronounced shifts in fish assemblage structure. Coral trout density also declined in response to the loss of live coral, however, the approximately 2:1 density ratio between NTRs and fished zones was maintained over time. The only post-disturbance refuges for coral trout spawning stocks were within the NTRs that escaped the worst effects of the disturbances. Although NTRs had little discernible effect on the temporal dynamics of benthic or fish communities, it was evident that the post-disturbance refuges for coral trout spawning stocks within some NTRs may be critically important to regional-scale population persistence and recovery.

Habitat dynamics, marine reserve status, and the decline and recovery of coral reef fish communities

PubMed Central

Williamson, David H; Ceccarelli, Daniela M; Evans, Richard D; Jones, Geoffrey P; Russ, Garry R

2014-01-01

Severe climatic disturbance events often have major impacts on coral reef communities, generating cycles of decline and recovery, and in some extreme cases, community-level phase shifts from coral-to algal-dominated states. Benthic habitat changes directly affect reef fish communities, with low coral cover usually associated with low fish diversity and abundance. No-take marine reserves (NTRs) are widely advocated for conserving biodiversity and enhancing the sustainability of exploited fish populations. Numerous studies have documented positive ecological and socio-economic benefits of NTRs; however, the ability of NTRs to ameliorate the effects of acute disturbances on coral reefs has seldom been investigated. Here, we test these factors by tracking the dynamics of benthic and fish communities, including the important fishery species, coral trout (Plectropomus spp.), over 8 years in both NTRs and fished areas in the Keppel Island group, Great Barrier Reef, Australia. Two major disturbances impacted the reefs during the monitoring period, a coral bleaching event in 2006 and a freshwater flood plume in 2011. Both disturbances generated significant declines in coral cover and habitat complexity, with subsequent declines in fish abundance and diversity, and pronounced shifts in fish assemblage structure. Coral trout density also declined in response to the loss of live coral, however, the approximately 2:1 density ratio between NTRs and fished zones was maintained over time. The only post-disturbance refuges for coral trout spawning stocks were within the NTRs that escaped the worst effects of the disturbances. Although NTRs had little discernible effect on the temporal dynamics of benthic or fish communities, it was evident that the post-disturbance refuges for coral trout spawning stocks within some NTRs may be critically important to regional-scale population persistence and recovery. PMID:24634720

Mortality, recovery, and community shifts of scleractinian corals in Puerto Rico one decade after the 2005 regional bleaching event

PubMed Central

Amirrezvani, Ali

2017-01-01

This work analyzes the mortality, recovery, and shifts in the composition of scleractinian corals from Puerto Rico one decade after the 2005 regional coral bleaching event. Temporal and spatial patterns of coral community structure were examined using a stratified, non-random sampling approach based on five permanent transects per reef at 16 reef stations. A negative correlation between percent coral cover loss and light attenuation coefficient (Kd490) was observed, suggesting that light attenuation, as influenced by water turbidity and depth, played a major role in coral protection during the bleaching event (“sunblock effect”). Responses of coral assemblages varied after the bleaching event, including shifts of cover from massive corals (Orbicella spp.) to opportunistic (Porites astreoides) and branching corals (Madracis auretenra, P. porites) and/or turf algae; partial recovery of reef substrate cover by O. annularis complex; and no measurable changes in coral assemblages before and after the event. PMID:28761791

Mortality, recovery, and community shifts of scleractinian corals in Puerto Rico one decade after the 2005 regional bleaching event.

PubMed

García-Sais, Jorge R; Williams, Stacey M; Amirrezvani, Ali

2017-01-01

This work analyzes the mortality, recovery, and shifts in the composition of scleractinian corals from Puerto Rico one decade after the 2005 regional coral bleaching event. Temporal and spatial patterns of coral community structure were examined using a stratified, non-random sampling approach based on five permanent transects per reef at 16 reef stations. A negative correlation between percent coral cover loss and light attenuation coefficient (Kd 490 ) was observed, suggesting that light attenuation, as influenced by water turbidity and depth, played a major role in coral protection during the bleaching event ("sunblock effect"). Responses of coral assemblages varied after the bleaching event, including shifts of cover from massive corals ( Orbicella spp.) to opportunistic ( Porites astreoides ) and branching corals ( Madracis auretenra , P. porites ) and/or turf algae; partial recovery of reef substrate cover by O. annularis complex; and no measurable changes in coral assemblages before and after the event.

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

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

USGS Publications Warehouse

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

2016-07-21

The Florida Keys reef tract (FKRT) is the largest coral-reef ecosystem in the continental United States. The modern FKRT extends for 362 kilometers along the coast of South Florida from Dry Tortugas National Park in the southwest, through the Florida Keys National Marine Sanctuary (FKNMS), to Fowey Rocks reef in Biscayne National Park in the northeast. Most reefs along the FKRT are sheltered by the exposed islands of the Florida Keys; however, large channels are located between the islands of the Middle Keys. These openings allow for tidal transport of water from Florida Bay onto reefs in the area. The characteristics of the water masses coming from Florida Bay, which can experience broad swings in temperature, salinity, nutrients, and turbidity over short periods of time, are generally unfavorable or “inimical” to coral growth and reef development.Although reef habitats are ubiquitous throughout most of the Upper and Lower Keys, relatively few modern reefs exist in the Middle Keys most likely because of the impacts of inimical waters from Florida Bay. The reefs that are present in the Middle Keys generally are poorly developed compared with reefs elsewhere in the region. For example, Acropora palmata has been the dominant coral on shallow-water reefs in the Caribbean over the last 1.5 million years until populations of the coral declined throughout the region in recent decades. Although A. palmata was historically abundant in the Florida Keys, it was conspicuously absent from reefs in the Middle Keys. Instead, contemporary reefs in the Middle Keys have been dominated by occasional massive (that is, boulder or head) corals and, more often, small, non-reef-building corals.Holocene reef cores have been collected from many locations along the FKRT; however, despite the potential importance of the history of reefs in the Middle Florida Keys to our understanding of the environmental controls on reef development throughout the FKRT, there are currently no published records of the Holocene history of reefs in the region. The objectives of the present study were to (1) provide general descriptions of unpublished core records from Alligator Reef and (2) collect and describe new Holocene reef cores from two additional locations in the Middle Keys: Sombrero and Tennessee Reefs.

Retention of Habitat Complexity Minimizes Disassembly of Reef Fish Communities following Disturbance: A Large-Scale Natural Experiment

PubMed Central

Emslie, Michael J.; Cheal, Alistair J.; Johns, Kerryn A.

2014-01-01

High biodiversity ecosystems are commonly associated with complex habitats. Coral reefs are highly diverse ecosystems, but are under increasing pressure from numerous stressors, many of which reduce live coral cover and habitat complexity with concomitant effects on other organisms such as reef fishes. While previous studies have highlighted the importance of habitat complexity in structuring reef fish communities, they employed gradient or meta-analyses which lacked a controlled experimental design over broad spatial scales to explicitly separate the influence of live coral cover from overall habitat complexity. Here a natural experiment using a long term (20 year), spatially extensive (∼115,000 kms2) dataset from the Great Barrier Reef revealed the fundamental importance of overall habitat complexity for reef fishes. Reductions of both live coral cover and habitat complexity had substantial impacts on fish communities compared to relatively minor impacts after major reductions in coral cover but not habitat complexity. Where habitat complexity was substantially reduced, species abundances broadly declined and a far greater number of fish species were locally extirpated, including economically important fishes. This resulted in decreased species richness and a loss of diversity within functional groups. Our results suggest that the retention of habitat complexity following disturbances can ameliorate the impacts of coral declines on reef fishes, so preserving their capacity to perform important functional roles essential to reef resilience. These results add to a growing body of evidence about the importance of habitat complexity for reef fishes, and represent the first large-scale examination of this question on the Great Barrier Reef. PMID:25140801

Retention of habitat complexity minimizes disassembly of reef fish communities following disturbance: a large-scale natural experiment.

PubMed

Emslie, Michael J; Cheal, Alistair J; Johns, Kerryn A

2014-01-01

High biodiversity ecosystems are commonly associated with complex habitats. Coral reefs are highly diverse ecosystems, but are under increasing pressure from numerous stressors, many of which reduce live coral cover and habitat complexity with concomitant effects on other organisms such as reef fishes. While previous studies have highlighted the importance of habitat complexity in structuring reef fish communities, they employed gradient or meta-analyses which lacked a controlled experimental design over broad spatial scales to explicitly separate the influence of live coral cover from overall habitat complexity. Here a natural experiment using a long term (20 year), spatially extensive (∼ 115,000 kms(2)) dataset from the Great Barrier Reef revealed the fundamental importance of overall habitat complexity for reef fishes. Reductions of both live coral cover and habitat complexity had substantial impacts on fish communities compared to relatively minor impacts after major reductions in coral cover but not habitat complexity. Where habitat complexity was substantially reduced, species abundances broadly declined and a far greater number of fish species were locally extirpated, including economically important fishes. This resulted in decreased species richness and a loss of diversity within functional groups. Our results suggest that the retention of habitat complexity following disturbances can ameliorate the impacts of coral declines on reef fishes, so preserving their capacity to perform important functional roles essential to reef resilience. These results add to a growing body of evidence about the importance of habitat complexity for reef fishes, and represent the first large-scale examination of this question on the Great Barrier Reef.

Microbial communities in the reef water at Kham Island, lower Gulf of Thailand.

PubMed

Somboonna, Naraporn; Wilantho, Alisa; Monanunsap, Somchai; Chavanich, Suchana; Tangphatsornruang, Sithichoke; Tongsima, Sissades

2017-01-01

Coral reefs are among the most biodiverse habitats on Earth, but knowledge of their associated marinemicrobiome remains limited. To increase the understanding of the coral reef ecosystem in the lower Gulf of Thailand, this study utilized 16S and 18S rRNA gene-based pyrosequencing to identify the prokaryotic and eukaryotic microbiota present in the reef water at Kham Island, Trat province, Thailand (N6.97 E100.86). The obtained result was then compared with the published microbiota from different coral reef water and marine sites. The coral reefs at Kham Island are of the fringe type. The reefs remain preserved and abundant. The community similarity indices (i.e., Lennon similarity index, Yue & Clayton similarity index) indicated that the prokaryotic composition of Kham was closely related to that of Kra, another fringing reef site in the lower Gulf of Thailand, followed by coral reef water microbiota at GS048b (Cooks Bay, Fr. Polynesia), Palmyra (Northern Line Islands, United States) and GS108b (Coccos Keeling, Australia), respectively. Additionally, the microbial eukaryotic populations at Kham was analyzed and compared with the available database at Kra. Both eukaryotic microbiota, in summer and winter seasons, were correlated. An abundance of Dinophysis acuminata was noted in the summer season, in accordance with its reported cause of diarrhoeatic shellfish outbreak in the summer season elsewhere. The slightly lower biodiversity in Kham than at Kra might reflect the partly habitat difference due to coastal anthropogenic activities and minor water circulation, as Kham locates close to the mainland and is surrounded by islands (e.g., Chang and Kut islands). The global marine microbiota comparison suggested relatively similar microbial structures among coral sites irrespective of geographical location, supporting the importance of coral-associated marine microbiomes, and Spearman's correlation analysis between community membership and factors of shore distance and seawater temperature indicated potential correlation of these factors ( p -values < 0.05) with Kham, Kra, and some other coral and coastal sites. Together, this study provided the second marine microbial database for the coral reef of the lower Gulf of Thailand, and a comparison of the coral-associated marine microbial diversity among global ocean sites.

78 FR 66683 - Fisheries in the Western Pacific; Special Coral Reef Ecosystem Fishing Permit

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-06

... the Western Pacific; Special Coral Reef Ecosystem Fishing Permit AGENCY: National Marine Fisheries... special coral reef ecosystem fishing permit. SUMMARY: NMFS issued a Special Coral Reef Ecosystem Fishing Permit that authorizes Kampachi Farms, LLC, to culture and harvest a coral reef ecosystem management unit...

76 FR 63904 - Proposed Information Collection; Comment Request; Coral Reef Conservation Program Administration

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-14

... Collection; Comment Request; Coral Reef Conservation Program Administration AGENCY: National Oceanic and... The Coral Reef Conservation Act of 2000 (Act) was enacted to provide a framework for conserving coral reefs. The Coral Reef Conservation Grant Program, under the Act, provides funds to broad- based...

Global coral disease prevalence associated with sea temperature anomalies and local factors.

PubMed

Ruiz-Moreno, Diego; Willis, Bette L; Page, A Cathie; Weil, Ernesto; Cróquer, Aldo; Vargas-Angel, Bernardo; Jordan-Garza, Adán Guillermo; Jordán-Dahlgren, Eric; Raymundo, Laurie; Harvell, C Drew

2012-09-12

Coral diseases are taking an increasing toll on coral reef structure and biodiversity and are important indicators of declining health in the oceans. We implemented standardized coral disease surveys to pinpoint hotspots of coral disease, reveal vulnerable coral families and test hypotheses about climate drivers from 39 locations worldwide. We analyzed a 3 yr study of coral disease prevalence to identify links between disease and a range of covariates, including thermal anomalies (from satellite data), location and coral cover, using a Generalized Linear Mixed Model. Prevalence of unhealthy corals, i.e. those with signs of known diseases or with other signs of compromised health, exceeded 10% on many reefs and ranged to over 50% on some. Disease prevalence exceeded 10% on 20% of Caribbean reefs and 2.7% of Pacific reefs surveyed. Within the same coral families across oceans, prevalence of unhealthy colonies was higher and some diseases were more common at sites in the Caribbean than those in the Pacific. The effects of high disease prevalence are potentially extensive given that the most affected coral families, the acroporids, faviids and siderastreids, are among the major reef-builders at these sites. The poritids and agaricids stood out in the Caribbean as being the most resistant to disease, even though these families were abundant in our surveys. Regional warm temperature anomalies were strongly correlated with high disease prevalence. The levels of disease reported here will provide a much-needed local reference point against which to compare future change.

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.

Tracing Carbon Flow Through Food Webs on Isolated Coral Reefs in the Central Pacific Ocean Using a Compound-Specific Stable Isotope Approach

NASA Astrophysics Data System (ADS)

Thorrold, S.; McMahon, K.; Braun, C.; Berumen, M. L.; Houghton, L. A.

2016-02-01

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 or benthic primary production and recycled detrital carbon. We coupled analyses of stable carbon isotopes in essential amino acids with Bayesian mixing models to quantify carbon flow from pelagic primary producers, benthic macroalgae and autotrophic symbionts in corals, along with detrital carbon, to coral reef fishes across several feeding guilds and trophic positions, including apex predators (gray reef and black tip reef sharks), on reefs in the Phoenix Islands Protected Area. Excellent separation in multivariate isotope space among end-members at the base of the food web allowed us to quantify the relative proportion of carbon produced by each of the end-members that is assimilated by focal reef fish species. Low local human impacts on the study reefs provided the opportunity to examine carbon fluxs in fully functioning reef food webs, thereby providing an important baseline for examingn human impacts in food webs on stressed reefs in more populated regions in the tropics. Moreover the study reefs are located along a significant gradient in dissolved N concentrations, allowing us to test if end-member proportions vary as a function of pelagic primary productivity levels. Our work provides insights into the roles that diverse carbon sources may play in the structure, function and resilience of coral reef ecosystems.

Phase shift from a coral to a corallimorph-dominated reef associated with a shipwreck on Palmyra atoll

USGS Publications Warehouse

Work, Thierry M.; Aeby, G.S.; Maragos, J.E.

2008-01-01

Coral reefs can undergo relatively rapid changes in the dominant biota, a phenomenon referred to as phase shift. Various reasons have been proposed to explain this phenomenon including increased human disturbance, pollution, or changes in coral reef biota that serve a major ecological function such as depletion of grazers. However, pinpointing the actual factors potentially responsible can be problematic. Here we show a phase shift from coral to the corallimorpharian Rhodactis howesii associated with a long line vessel that wrecked in 1991 on an isolated atoll (Palmyra) in the central Pacific Ocean. We documented high densities of R. howesii near the ship that progressively decreased with distance from the ship whereas R. howesii were rare to absent in other parts of the atoll. We also confirmed high densities of R. howesii around several buoys recently installed on the atoll in 2001. This is the first time that a phase shift on a coral leef has been unambiguously associated with man-made structures. This association was made, in part, because of the remoteness of Palmyra and its recent history of minimal human habitation or impact. Phase shifts can have long-term negative ramification for coral reefs, and eradication of organisms responsible for phase shifts in marine ecosystems can be difficult, particularly if such organisms cover a large area. The extensive R. howesii invasion and subsequent loss of coral reef habitat at Palmyra also highlights the importance of rapid removal of shipwrecks on corals reefs to mitigate the potential of reef overgrowth by invasives.

Small Marine Protected Areas in Fiji Provide Refuge for Reef Fish Assemblages, Feeding Groups, and Corals

PubMed Central

Pires, Mathias M.; Guimarães, Paulo Roberto; Hoey, Andrew S.; Hay, Mark E.

2017-01-01

The establishment of no-take marine protected areas (MPAs) on coral reefs is a common management strategy for conserving the diversity, abundance, and biomass of reef organisms. Generally, well-managed and enforced MPAs can increase or maintain the diversity and function of the enclosed coral reef, with some of the benefits extending to adjacent non-protected reefs. A fundamental question in coral reef conservation is whether these benefits arise within small MPAs (<1 km2), because larval input of reef organisms is largely decoupled from local adult reproduction. We examined the structure of fish assemblages, composition of fish feeding groups, benthic cover, and key ecosystem processes (grazing, macroalgal browsing, and coral replenishment) in three small (0.5–0.8 km2) no-take MPAs and adjacent areas where fisheries are allowed (non-MPAs) on coral reefs in Fiji. The MPAs exhibited greater species richness, density, and biomass of fishes than non-MPAs. Furthermore, MPAs contained a greater abundance and biomass of grazing herbivores and piscivores as well as a greater abundance of cleaners than fished areas. We also found differences in fish associations when foraging, with feeding groups being generally more diverse and having greater biomass within MPAs than adjacent non-MPAs. Grazing by parrotfishes was 3–6 times greater, and macroalgal browsing was 3–5 times greater in MPAs than in non-MPAs. On average, MPAs had 260–280% as much coral cover and only 5–25% as much macroalgal cover as their paired non-MPA sites. Finally, two of the three MPAs had three-fold more coral recruits than adjacent non-MPAs. The results of this study indicate that small MPAs benefit not only populations of reef fishes, but also enhance ecosystem processes that are critical to reef resilience within the MPAs. PMID:28122006

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. Copyright © 2014, American Association for the Advancement of Science.

Quaternary onset and evolution of Kimberley coral reefs (Northwest Australia) revealed by high-resolution seismic imaging

NASA Astrophysics Data System (ADS)

Bufarale, Giada; Collins, Lindsay B.; O'Leary, Michael J.; Stevens, Alexandra; Kordi, Moataz; Solihuddin, Tubagus

2016-07-01

The inner shelf Kimberley Bioregion of Northwest Australia is characterised by a macrotidal setting where prolific coral reefs growth as developed around a complex drowned landscape and is considered a biodiversity "hotspot". High-resolution shallow seismic studies were conducted across various reef settings in the Kimberley (Buccaneer Archipelago, north of Dampier Peninsula, latitude: between 16°40‧S and 16°00‧S) to evaluate stratigraphic evolution, interaction with different substrates, morphological patterns and distribution. Reef sites were chosen to assess most of the reef types present, particularly high intertidal planar reefs and fringing reefs. Reef internal acoustic reflectors were identified according to their shape, stratigraphic position and characteristics. Two main seismic horizons were identified marking the boundaries between Holocene reef (Marine Isotope Stage 1, MIS 1, last 12 ky), commonly 10-20 m thick, and MIS 5 (Last Interglacial, LIG, ~120 ky, up to 12 m thick) and Proterozoic rock foundation over which Quaternary reef growth occurred. Within the Holocene Reef unit, at least three minor internal reflectors, generally discontinuous, subparallel to the reef flat were recognised and interpreted as either growth hiatuses or a change of the coral framework or sediment matrix. The LIG reefs represent a new northernmost occurrence along the Western Australian coast. The research presented here achieved the first regional geophysical study of the Kimberley reefs. Subbottom profiles demonstrated that the surveyed reefs are characterised by a multi-stage reef buildup, indicating that coral growth occurred in the Kimberley during previous sea level highstands. The data show also that antecedent substrate and regional subsidence have contributed, too, in determining the amount of accommodation available for reef growth and controlling the morphology of the successive reef building stages. Moreover, the study showed that in spite of macrotidal conditions, high-turbidity and frequent high-energy cyclonic events, corals have exhibited prolific reef growth during the Holocene developing significant reef accretionary structures. As a result coral reefs have generating habitat complexity and species diversity in what is a biodiversity hotspot.

Larval retention and connectivity among populations of corals and reef fishes: history, advances and challenges

NASA Astrophysics Data System (ADS)

Jones, G. P.; Almany, G. R.; Russ, G. R.; Sale, P. F.; Steneck, R. S.; van Oppen, M. J. H.; Willis, B. L.

2009-06-01

The extent of larval dispersal on coral reefs has important implications for the persistence of coral reef metapopulations, their resilience and recovery from an increasing array of threats, and the success of protective measures. This article highlights a recent dramatic increase in research effort and a growing diversity of approaches to the study of larval retention within (self-recruitment) and dispersal among (connectivity) isolated coral reef populations. Historically, researchers were motivated by alternative hypotheses concerning the processes limiting populations and structuring coral reef assemblages, whereas the recent impetus has come largely from the need to incorporate dispersal information into the design of no-take marine protected area (MPA) networks. Although the majority of studies continue to rely on population genetic approaches to make inferences about dispersal, a wide range of techniques are now being employed, from small-scale larval tagging and paternity analyses, to large-scale biophysical circulation models. Multiple approaches are increasingly being applied to cross-validate and provide more realistic estimates of larval dispersal. The vast majority of empirical studies have focused on corals and fishes, where evidence for both extremely local scale patterns of self-recruitment and ecologically significant connectivity among reefs at scales of tens of kilometers (and in some cases hundreds of kilometers) is accumulating. Levels of larval retention and the spatial extent of connectivity in both corals and fishes appear to be largely independent of larval duration or reef size, but may be strongly influenced by geographic setting. It is argued that high levels of both self-recruitment and larval import can contribute to the resilience of reef populations and MPA networks, but these benefits will erode in degrading reef environments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goreau, T.J.; Hilbertz, W.

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 reefsmore » 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.« less

Habitat degradation and fishing effects on the size structure of coral reef fish communities.

PubMed

Wilson, S K; Fisher, R; Pratchett, M S; Graham, N A J; Dulvy, N K; Turner, R A; Cakacaka, A; Polunin, N V C

2010-03-01

Overfishing and habitat degradation through climate change pose the greatest threats to sustainability of marine resources on coral reefs. We examined how changes in fishing pressure and benthic habitat composition influenced the size spectra of island-scale reef fish communities in Lau, Fiji. Between 2000 and 2006 fishing pressure declined in the Lau Islands due to declining human populations and reduced demand for fresh fish. At the same time, coral cover declined and fine-scale architectural complexity eroded due to coral bleaching and outbreaks of crown-of-thorns starfish, Acanthaster planci. We examined the size distribution of reef fish communities using size spectra analysis, the linearized relationship between abundance and body size class. Spatial variation in fishing pressure accounted for 31% of the variation in the slope of the size spectra in 2000, higher fishing pressure being associated with a steeper slope, which is indicative of fewer large-bodied fish and/or more small-bodied fish. Conversely, in 2006 spatial variation in habitat explained 53% of the variation in the size spectra slopes, and the relationship with fishing pressure was much weaker (approximately 12% of variation) than in 2000. Reduced cover of corals and lower structural complexity was associated with less steep size spectra slopes, primarily due to reduced abundance of fish < 20 cm. Habitat degradation will compound effects of fishing on coral reefs as increased fishing reduces large-bodied target species, while habitat loss results in fewer small-bodied juveniles and prey that replenish stocks and provide dietary resources for predatory target species. Effective management of reef resources therefore depends on both reducing fishing pressure and maintaining processes that encourage rapid recovery of coral habitat.

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spatial variation in abundance, size and orientation of juvenile corals related to the biomass of parrotfishes on the Great Barrier Reef, Australia.

PubMed

Trapon, Melanie L; Pratchett, Morgan S; Hoey, Andrew S

2013-01-01

For species with complex life histories such as scleractinian corals, processes occurring early in life can greatly influence the number of individuals entering the adult population. A plethora of studies have examined settlement patterns of coral larvae, mostly on artificial substrata, and the composition of adult corals across multiple spatial and temporal scales. However, relatively few studies have examined the spatial distribution of small (≤50 mm diameter) sexually immature corals on natural reef substrata. We, therefore, quantified the variation in the abundance, composition and size of juvenile corals (≤50 mm diameter) among 27 sites, nine reefs, and three latitudes spanning over 1000 km on Australia's Great Barrier Reef. Overall, 2801 juveniles were recorded with a mean density of 6.9 (±0.3 SE) ind.m(-2), with Acropora, Pocillopora, and Porites accounting for 84.1% of all juvenile corals surveyed. Size-class structure, orientation on the substrate and taxonomic composition of juvenile corals varied significantly among latitudinal sectors. The abundance of juvenile corals varied both within (6-13 ind.m(-2)) and among reefs (2.8-11.1 ind.m(-2)) but was fairly similar among latitudes (6.1-8.2 ind.m(-2)), despite marked latitudinal variation in larval supply and settlement rates previously found at this scale. Furthermore, the density of juvenile corals was negatively correlated with the biomass of scraping and excavating parrotfishes across all sites, revealing a potentially important role of parrotfishes in determining distribution patterns of juvenile corals on the Great Barrier Reef. While numerous studies have advocated the importance of parrotfishes for clearing space on the substrate to facilitate coral settlement, our results suggest that at high biomass they may have a detrimental effect on juvenile coral assemblages. There is, however, a clear need to directly quantify rates of mortality and growth of juvenile corals to understand the relative importance of these mechanisms in shaping juvenile, and consequently adult, coral assemblages.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyazaki, Tadakuni; Harashima, Akira; Nakatani, Yukihiro

Coral reefs are the major sites for photo-synthesis and calcification in the present ocean. Estimating the production rate of calcification by the coral reefs or investigating the sink/source mechanism of CO{sub 2} by the coral reefs in the ocean, the distribution of the coral reefs in the world wide must be identified. Measuring the spectral signatures of underwater coral reefs and mapping of coral reefs by satellite remote sensing are described. The spectral signatures of different species of the coral reefs were measured using a spectroradiometer at off Kuroshima Island, Okinawa, Japan and investigated spectral difference between different species ofmore » the coral reefs. As well as the field experiments, laboratory experiments for measuring the spectral signatures of 9 different species of coral reefs were carried out with the same spectroradiometer. The spectral reflectance of each coral reef showed a significant result that a narrow absorption band exists in the spectral region between 660 and 680 nm, and very strong spectral reflectance from about 700 nm towards the longer wavelength range. On the other hand, absorption and the high reflectance region were not observed from the bottom sands or bare rocks underwater. These experiments suggested that there is a significant spectral difference between coral reefs and bottom sands or bare rocks and so the best spectral range for separating the coral reefs from other underwater objects in the ocean would be between 700 and 800 nm. As well as the basic spectral measurement either in the field or at the laboratory, SPOT satellite imageries were used to classify the underwater coral reefs. Classification methods used here were the principal component analysis, and the maximum likelihood. Finally, the evaluation of classification method for extracting the coral reefs was introduced.« less

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.

Historical baselines of coral cover on tropical reefs as estimated by expert opinion

PubMed Central

Cheung, William W.L.; Bruno, John F.

2018-01-01

Coral reefs are important habitats that represent global marine biodiversity hotspots and provide important benefits to people in many tropical regions. However, coral reefs are becoming increasingly threatened by climate change, overfishing, habitat destruction, and pollution. Historical baselines of coral cover are important to understand how much coral cover has been lost, e.g., to avoid the ‘shifting baseline syndrome’. There are few quantitative observations of coral reef cover prior to the industrial revolution, and therefore baselines of coral reef cover are difficult to estimate. Here, we use expert and ocean-user opinion surveys to estimate baselines of global coral reef cover. The overall mean estimated baseline coral cover was 59% (±19% standard deviation), compared to an average of 58% (±18% standard deviation) estimated by professional scientists. We did not find evidence of the shifting baseline syndrome, whereby respondents who first observed coral reefs more recently report lower estimates of baseline coral cover. These estimates of historical coral reef baseline cover are important for scientists, policy makers, and managers to understand the extent to which coral reefs have become depleted and to set appropriate recovery targets. PMID:29379692

Historical baselines of coral cover on tropical reefs as estimated by expert opinion.

PubMed

Eddy, Tyler D; Cheung, William W L; Bruno, John F

2018-01-01

Coral reefs are important habitats that represent global marine biodiversity hotspots and provide important benefits to people in many tropical regions. However, coral reefs are becoming increasingly threatened by climate change, overfishing, habitat destruction, and pollution. Historical baselines of coral cover are important to understand how much coral cover has been lost, e.g., to avoid the 'shifting baseline syndrome'. There are few quantitative observations of coral reef cover prior to the industrial revolution, and therefore baselines of coral reef cover are difficult to estimate. Here, we use expert and ocean-user opinion surveys to estimate baselines of global coral reef cover. The overall mean estimated baseline coral cover was 59% (±19% standard deviation), compared to an average of 58% (±18% standard deviation) estimated by professional scientists. We did not find evidence of the shifting baseline syndrome, whereby respondents who first observed coral reefs more recently report lower estimates of baseline coral cover. These estimates of historical coral reef baseline cover are important for scientists, policy makers, and managers to understand the extent to which coral reefs have become depleted and to set appropriate recovery targets.

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...

A Biophysical Model for Hawaiian Coral Reefs: Coupling Local Ecology, Larval Transport and Climate Change

NASA Astrophysics Data System (ADS)

Kapur, M. R.

2016-02-01

Simulative models of reef ecosystems have been used to evaluate ecological responses to a myriad of disturbance events, including fishing pressure, coral bleaching, invasion by alien species, and nutrient loading. The Coral Reef Scenario Evaluation Tool (CORSET), has been developed and instantiated for both the Meso-American Reef (MAR) and South China Sea (SCS) regions. This model is novel in that it accounts for the many scales at which reef ecosystem processes take place; is comprised of a "bottom-up" structure wherein complex behaviors are not pre-programmed, but emergent and highly portable to new systems. Local-scale dynamics are coupled across regions through larval connectivity matrices, derived sophisticated particle transport simulations that include key elements of larval behavior. By this approach, we are able to directly evaluate some of the potential consequences of larval connectivity patterns across a range of spatial scales and under multiple climate scenarios. This work develops and applies the CORSET (Coral Reef Scenario Evaluation Tool) to the Main Hawaiian Islands under a suite of climate and ecological scenarios. We introduce an adaptation constant into reef-building coral dynamics to simulate observed resiliencies to bleaching events. This presentation will share results from the model's instantiation under two Resource Concentration Pathway climate scenarios, with emphasis upon larval connectivity dynamics, emergent coral tolerance to increasing thermal anomalies, and patterns of spatial fishing closures. Results suggest that under a business-as-usual scenario, thermal tolerance and herbivore removal will have synergistic effects on reef resilience.

Patterns in reef fish assemblages: Insights from the Chagos Archipelago.

PubMed

Samoilys, Melita; Roche, Ronan; Koldewey, Heather; Turner, John

2018-01-01

Understanding the drivers of variability in the composition of fish assemblages across the Indo-Pacific region is crucial to support coral reef ecosystem resilience. Whilst numerous relationships and feedback mechanisms between the functional roles of coral reef fishes and reef benthic composition have been investigated, certain key groups, such as the herbivores, are widely suggested to maintain reefs in a coral-dominated state. Examining links between fishes and reef benthos is complicated by the interactions between natural processes, disturbance events and anthropogenic impacts, particularly fishing pressure. This study examined fish assemblages and associated benthic variables across five atolls within the Chagos Archipelago, where fishing pressure is largely absent, to better understand these relationships. We found high variability in fish assemblages among atolls and sites across the archipelago, especially for key groups such as a suite of grazer-detritivore surgeonfish, and the parrotfishes which varied in density over 40-fold between sites. Differences in fish assemblages were significantly associated with variable levels of both live and recently dead coral cover and rugosity. We suggest these results reflect differing coral recovery trajectories following coral bleaching events and a strong influence of 'bottom-up' control mechanisms on fish assemblages. Species level analyses revealed that Scarus niger, Acanthurus nigrofuscus and Chlorurus strongylocephalos were key species driving differences in fish assemblage structure. Clarifying the trophic roles of herbivorous and detritivorous reef fishes will require species-level studies, which also examine feeding behaviour, to fully understand their contribution in maintaining reef resilience to climate change and fishing impacts.

Shifts in coral-assemblage composition do not ensure persistence of reef functionality.

PubMed

Alvarez-Filip, Lorenzo; Carricart-Ganivet, Juan P; Horta-Puga, Guillermo; Iglesias-Prieto, Roberto

2013-12-12

Coral communities are changing rapidly worldwide through loss of coral cover and shifts in species composition. Although many reef-building corals are likely to decline, some weedy opportunistic species might increase in abundance. Here we explore whether the reshuffling of species can maintain ecosystem integrity and functioning. Using four common Caribbean reef-building coral genera we modeled rates of reef construction and complexity. We show that shifting coral assemblages result in rapid losses in coral-community calcification and reef rugosity that are independent of changes in the total abundance of reef corals. These losses are considerably higher than those recently attributed to climate change. Dominance patterns of coral assemblages seem to be the most important driver of the functioning of coral reefs and thus, the future of these ecosystems might depend not only on reductions of local and global stressors, but also on the maintenance of keystone coral species.

Variation in size frequency distribution of coral populations under different fishing pressures in two contrasting locations in the Indian Ocean.

PubMed

Grimsditch, G; Pisapia, C; Huck, M; Karisa, J; Obura, D; Sweet, M

2017-10-01

This study aimed to assess how the size-frequency distributions of coral genera varied between reefs under different fishing pressures in two contrasting Indian Ocean locations (the Maldives and East Africa). Using generalized linear mixed models, we were able to demonstrate that complex interactions occurred between coral genera, coral size class and fishing pressure. In both locations, we found Acropora coral species to be more abundant in non-fished compared to fished sites (a pattern which was consistent for nearly all the assessed size classes). Coral genera classified as 'stress tolerant' showed a contrasting pattern i.e. were higher in abundance in fished compared to non-fished sites. Site specific variations were also observed. For example, Maldivian reefs exhibited a significantly higher abundance in all size classes of 'competitive' corals compared to East Africa. This possibly indicates that East African reefs have already been subjected to higher levels of stress and are therefore less suitable environments for 'competitive' corals. This study also highlights the potential structure and composition of reefs under future degradation scenarios, for example with a loss of Acropora corals and an increase in dominance of 'stress tolerant' and 'generalist' coral genera. Copyright © 2017. Published by Elsevier Ltd.

Resilience potential of an Indian Ocean reef: an assessment through coral recruitment pattern and survivability of juvenile corals to recurrent stress events.

PubMed

Manikandan, Balakrishnan; Ravindran, Jeyaraman; Vidya, Pottekkatt Jayabalan; Shrinivasu, Selvaraju; Manimurali, Rajagopal; Paramasivam, Kaliyaperumal

2017-05-01

Coral reefs are degraded by the synergistic action of climate and anthropogenic stressors. Coral cover in the Palk Bay reef at the northern Indian Ocean largely declined in the past decade due to frequent bleaching events, tsunami and increased fishing activities. In this study, we carried out a comparative assessment to assess the differences in the recovery and resilience of three spatially distant reefs viz. Vedhalai, Mandapam and Pamban along Palk Bay affected by moderate, severe and low fishing pressure respectively. The assessment was based on the juvenile coral recruitment pattern and its survivability combined with availability of hard substratum, live coral cover and herbivore reef fish stock. The Vedhalai reef has the highest coral cover (14.6 ± 6.3%), and ≥90% of the live corals in Vedhalai and Mandapam were affected by turf algal overgrowth. The density of herbivore reef fish was low in Vedhalai and Mandapam reefs compared to the Pamban reef with relatively few grazing species. The juvenile coral diversity and density were high in the Pamban reef and low in Vedhalai and Mandapam reefs despite high hard substratum cover. In total, 22 species of juvenile corals of 10 genera were recorded in Palk Bay. Comparison of the species diversity of juvenile corals with adult ones suggested that the Pamban reef is connected with other distant reefs whereas Vedhalai and Mandapam reefs were self-seeded. There was no statistically significant difference in the survivability of juvenile corals between the study sites, and in total, ≥90% of the juvenile corals survived the high sedimentation stress triggered by the northeast monsoon and bleaching stress that occurred recurrently. Our results indicated that the human activities indirectly affected the juvenile coral recruitment by degrading the live coral cover and contributed to the spatial variation in the recovery and resilience of the Palk Bay reef. Low species diversity of the juvenile corals will increase the vulnerability of the Palk Bay reef to species-specific endemic threats.

Spatial Patterns in Herbivory on a Coral Reef Are Influenced by Structural Complexity but Not by Algal Traits

PubMed Central

Vergés, Adriana; Vanderklift, Mathew A.; Doropoulos, Christopher; Hyndes, Glenn A.

2011-01-01

Background Patterns of herbivory can alter the spatial structure of ecosystems, with important consequences for ecosystem functions and biodiversity. While the factors that drive spatial patterns in herbivory in terrestrial systems are well established, comparatively less is known about what influences the distribution of herbivory in coral reefs. Methodology and Principal Findings We quantified spatial patterns of macroalgal consumption in a cross-section of Ningaloo Reef (Western Australia). We used a combination of descriptive and experimental approaches to assess the influence of multiple macroalgal traits and structural complexity in establishing the observed spatial patterns in macroalgal herbivory, and to identify potential feedback mechanisms between herbivory and macroalgal nutritional quality. Spatial patterns in macroalgal consumption were best explained by differences in structural complexity among habitats. The biomass of herbivorous fish, and rates of herbivory were always greater in the structurally-complex coral-dominated outer reef and reef flat habitats, which were also characterised by high biomass of herbivorous fish, low cover and biomass of macroalgae and the presence of unpalatable algae species. Macroalgal consumption decreased to undetectable levels within 75 m of structurally-complex reef habitat, and algae were most abundant in the structurally-simple lagoon habitats, which were also characterised by the presence of the most palatable algae species. In contrast to terrestrial ecosystems, herbivory patterns were not influenced by the distribution, productivity or nutritional quality of resources (macroalgae), and we found no evidence of a positive feedback between macroalgal consumption and the nitrogen content of algae. Significance This study highlights the importance of seascape-scale patterns in structural complexity in determining spatial patterns of macroalgal consumption by fish. Given the importance of herbivory in maintaining the ability of coral reefs to reorganise and retain ecosystem functions following disturbance, structural complexity emerges as a critical feature that is essential for the healthy functioning of these ecosystems. PMID:21347254

Cryptic Coral Reef Diversity Across the Pacific Assessed using Autonomous Reef Monitoring Structures and Multi-omic Methods

NASA Astrophysics Data System (ADS)

Ransome, E. J.; Timmers, M.; Hartmann, A.; Collins, A.; Meyer, C.

2016-02-01

Coral reefs harbor diverse and distinct eukaryotic, bacterial and viral communities, which are critically important for their success. The lack of standardized measures for comprehensively assessing reef diversity has been a major obstacle in understanding the complexity of eukaryotic and microbial associations, and the processes that drive ecosystem shifts on reefs. ARMS, which mimic the structural complexity of the reef using artificial settlement plates, were used to systematically measure reef biodiversity across the Indo-Pacific. This device allows for standardized sampling of reef microbes to metazoans, providing the opportunity to investigate the fundamental links between these groups at an ecosystem level. We integrate the use of traditional ecology methods with metagenomics and metabolomics (metabolic predictors) to quantify the taxonomic composition of one of the planet's most diverse ecosystems and to assess the fundamental links between these cryptic communities and ecosystem function along geographical and anthropogenic stress gradients.

Using coral disease prevalence to assess the effects of concentrating tourism activities on offshore reefs in a tropical marine park.

PubMed

Lamb, Joleah B; Willis, Bette L

2011-10-01

Concentrating tourism activities can be an effective way to closely manage high-use parks and minimize the extent of the effects of visitors on plants and animals, although considerable investment in permanent tourism facilities may be required. On coral reefs, a variety of human-related disturbances have been associated with elevated levels of coral disease, but the effects of reef-based tourist facilities (e.g., permanent offshore visitor platforms) on coral health have not been assessed. In partnership with reef managers and the tourism industry, we tested the effectiveness of concentrating tourism activities as a strategy for managing tourism on coral reefs. We compared prevalence of brown band disease, white syndromes, black band disease, skeletal eroding band, and growth anomalies among reefs with and without permanent tourism platforms within the Great Barrier Reef Marine Park. Coral diseases were 15 times more prevalent at reefs with offshore tourism platforms than at nearby reefs without platforms. The maximum prevalence and maximum number of cases of each disease type were recorded at reefs with permanently moored tourism platforms. Diseases affected 10 coral genera from 7 families at reefs with platforms and 4 coral genera from 3 families at reefs without platforms. The greatest number of disease cases occurred within the spatially dominant acroporid corals, which exhibited 18-fold greater disease prevalence at reefs with platforms than at reefs without platforms. Neither the percent cover of acroporids nor overall coral cover differed significantly between reefs with and without platforms, which suggests that neither factor was responsible for the elevated levels of disease. Identifying how tourism activities and platforms facilitate coral disease in marine parks will help ensure ongoing conservation of coral assemblages and tourism. ©2011 Society for Conservation Biology.

Pattern and intensity of human impact on coral reefs depend on depth along the reef profile and on the descriptor adopted

NASA Astrophysics Data System (ADS)

Nepote, Ettore; Bianchi, Carlo Nike; Chiantore, Mariachiara; Morri, Carla; Montefalcone, Monica

2016-09-01

Coral reefs are threatened by multiple global and local disturbances. The Maldives, already heavily hit by the 1998 mass bleaching event, are currently affected also by growing tourism and coastal development that may add to global impacts. Most of the studies investigating effects of local disturbances on coral reefs assessed the response of communities along a horizontal distance from the impact source. This study investigated the status of a Maldivian coral reef around an island where an international touristic airport has been recently (2009-2011) built, at different depths along the reef profile (5-20 m depth) and considering the change in the percentage of cover of five different non-taxonomic descriptors assessed through underwater visual surveys: hard corals, soft corals, other invertebrates, macroalgae and abiotic attributes. Eight reefs in areas not affected by any coastal development were used as controls and showed a reduction of hard coral cover and an increase of abiotic attributes (i.e. sand, rock, coral rubble) at the impacted reef. However, hard coral cover, the most widely used descriptor of coral reef health, was not sufficient on its own to detect subtle indirect effects that occurred down the reef profile. Selecting an array of descriptors and considering different depths, where corals may find a refuge from climate impacts, could guide the efforts of minimising local human pressures on coral reefs.

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 to increase resilience and guarantee the adaptation of this ecosystem to climate change. Thus, considering that the majority of the marine ecosystem services we benefit from are provided from coastal habitats, of which coral reefs play an important role, the challenge at hand is in fact the interaction between local factors and climate change

Maternal effects and Symbiodinium community composition drive differential patterns in juvenile survival in the coral Acropora tenuis

PubMed Central

Willis, Bette L.; Bay, Line K.

2016-01-01

Coral endosymbionts in the dinoflagellate genus Symbiodinium are known to impact host physiology and have led to the evolution of reef-building, but less is known about how symbiotic communities in early life-history stages and their interactions with host parental identity shape the structure of coral communities on reefs. Differentiating the roles of environmental and biological factors driving variation in population demographic processes, particularly larval settlement, early juvenile survival and the onset of symbiosis is key to understanding how coral communities are structured and to predicting how they are likely to respond to climate change. We show that maternal effects (that here include genetic and/or effects related to the maternal environment) can explain nearly 24% of variation in larval settlement success and 5–17% of variation in juvenile survival in an experimental study of the reef-building scleractinian coral, Acropora tenuis. After 25 days on the reef, Symbiodinium communities associated with juvenile corals differed significantly between high mortality and low mortality families based on estimates of taxonomic richness, composition and relative abundance of taxa. Our results highlight that maternal and familial effects significantly explain variation in juvenile survival and symbiont communities in a broadcast-spawning coral, with Symbiodinium type A3 possibly a critical symbiotic partner during this early life stage. PMID:27853562

First description of the neuro-anatomy of a larval coral reef fish Amphiprion ocellaris.

PubMed

Jacob, H; Metian, M; Brooker, R M; Duran, E; Nakamura, N; Roux, N; Masanet, P; Soulat, O; Lecchini, D

2016-09-01

The present study described the neuro-anatomy of a larval coral reef fish Amphiprion ocellaris and hypothesized that morphological changes during the transition from the oceanic environment to a reef environment (i.e. recruitment) have the potential to be driven by changes to environmental conditions and associated changes to cognitive requirements. Quantitative comparisons were made of the relative development of three specific brain areas (telencephalon, mesencephalon and cerebellum) between 6 days post-hatch (dph) larvae (oceanic phase) and 11 dph (at reef recruitment). The results showed that 6 dph larvae had at least two larger structures (telencephalon and mesencephalon) than 11 dph larvae, while the size of cerebellum remained identical. These results suggest that the structure and organization of the brain may reflect the cognitive demands at every stage of development. This study initiates analysis of the relationship between behavioural ecology and neuroscience in coral reef fishes. © 2016 The Fisheries Society of the British Isles.

The role of vision for navigation in the crown-of-thorns seastar, Acanthaster planci

PubMed Central

Sigl, Robert; Steibl, Sebastian; Laforsch, Christian

2016-01-01

Coral reefs all over the Indo-Pacific suffer from substantial damage caused by the crown-of-thorns seastar Acanthaster planci, a voracious predator that moves on and between reefs to seek out its coral prey. Chemoreception is thought to guide A. planci. As vision was recently introduced as another sense involved in seastar navigation, we investigated the potential role of vision for navigation in A. planci. We estimated the spatial resolution and visual field of the compound eye using histological sections and morphometric measurements. Field experiments in a semi-controlled environment revealed that vision in A. planci aids in finding reef structures at a distance of at least 5 m, whereas chemoreception seems to be effective only at very short distances. Hence, vision outweighs chemoreception at intermediate distances. A. planci might use vision to navigate between reef structures and to locate coral prey, therefore improving foraging efficiency, especially when multidirectional currents and omnipresent chemical cues on the reef hamper chemoreception. PMID:27476750

A Synthesis and Comparison of Approaches for Quantifying Coral Reef Structure

NASA Astrophysics Data System (ADS)

Duvall, M. S.; Hench, J. L.

2016-02-01

The complex physical structures of coral reefs provide substrate for benthic organisms, surface area for material fluxes, and have been used as a predictor of reef-fish biomass and biodiversity. Coral reef topography has a first order effect on reef hydrodynamics by imposing drag forces and increasing momentum and scalar dispersion. Despite its importance, quantifying reef topography remains a challenge, as it is patchy and discontinuous while also varying over orders of magnitude in spatial scale. Previous studies have quantified reef structure using a range of 1D and 2D metrics that estimate vertical roughness, which is the departure from a flat geometric profile or surface. However, there is no general mathematical or conceptual framework by which to apply or compare these roughness metrics. While the specific calculations of different metrics vary, we propose that they can be classified into four categories based on: 1) vertical relief relative to a reference height; 2) gradients in vertical relief; 3) surface contour distance; or 4) variations in roughness with scale. We apply metrics from these four classes to idealized reef topography as well as natural reef topography data from Moorea, French Polynesia. Through the use of idealized profiles, we demonstrate the potential for reefs with different morphologies to possess the same value for some scale-dependent metrics (i.e. classes 1-3). Due to the superposition of variable-scale roughness elements in reef topography, we find that multi-scale metrics (i.e. class 4) can better characterize structural complexity by capturing surface roughness across a range of spatial scales. In particular, we provide evidence of the ability of 1D continuous wavelet transforms to detect changes in dominant roughness scales on idealized topography as well as within real reef systems.

Chemically mediated behavior of recruiting corals and fishes: A tipping point that may limit reef recovery

PubMed Central

Dixson, Danielle L; Abrego, David; Hay, Mark E

2015-01-01

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. PMID:25146281

Artificial Reefs Created by Electrolysis and Coral Transplantation: An Approach Ensuring the Compatibility of Environmental Protection and Diving Tourism

NASA Astrophysics Data System (ADS)

van Treeck, P.; Schuhmacher, H.

1999-08-01

Coral reefs are currently being subjected to increasing pressure caused by water sports, especially scuba diving. Highly complex reef coenoses are affected by mechanical breakage and the coverage of corals by resuspended sediments. As the ecological capacity of the biocoenosis is exceeded, sensitive species are suppressed and the community is impoverished. The conflict between the needs of nature conservation and the economic interests of diving tourism can be mitigated by the creation of artificial underwater attractions as reef substitutes. Specially designed underwater structures are ideal for many diving activities, which can be diverted from sensitive natural habitats in that way. It is also possible to develop model reef communities for training and environmental education purposes. Our new concept is based on the elegant solution, proposed by Hilbertz et al. (1977), of depositing calcium minerals from the seawater in situ by electrolysis. We report on experiments conducted near Aqaba (Red Sea) showing that it is feasible to transplant living coral fragments on to the substrate being developed by electrochemical processes. In this way, the formation of a diverse community on any structure desired can be considerably enhanced.

Localised hydrodynamics influence vulnerability of coral communities to environmental disturbances

NASA Astrophysics Data System (ADS)

Shedrawi, George; Falter, James L.; Friedman, Kim J.; Lowe, Ryan J.; Pratchett, Morgan S.; Simpson, Christopher J.; Speed, Conrad W.; Wilson, Shaun K.; Zhang, Zhenlin

2017-09-01

The movement of water can have a significant influence on the vulnerability of hermatypic corals to environmental disturbances such as cyclone damage, heat stress and anoxia. Here, we explore the relationship between small reef-scale water circulation patterns and measured differences in the abundance, composition and vulnerability of coral assemblages over decades. Changes in coral cover and community structure within Bill's Bay (Ningaloo Reef, Western Australia) over a 22-yr period, during which multiple disturbance events (including mass bleaching, anoxia, and tropical cyclones) have impacted the area, were compared with spatial variation in water residence times (WRT). We found that reef sites associated with longer water residence times (WRT >15 h) experienced higher rates of coral mortality during acute environmental disturbances compared to reef sites with shorter WRT. Shifts in coral community composition from acroporid to faviid-dominated assemblages were also more prominent at sites with long WRT compared to reef sites with shorter WRT, although shifts in community composition were also observed at sites close to shore. Interestingly, these same long-WRT sites also tended to have the fastest recovery rates so that coral cover was returned to original levels of approximately 20% over two decades. This study provides empirical evidence that spatial patterns in water circulation and flushing can influence the resilience of coral communities, thus identifying areas sensitive to emerging threats associated with global climate change.

Phase shifts and the role of herbivory in the resilience of coral reefs

NASA Astrophysics Data System (ADS)

Ledlie, M. H.; Graham, N. A. J.; Bythell, J. C.; Wilson, S. K.; Jennings, S.; Polunin, N. V. C.; Hardcastle, J.

2007-09-01

Cousin Island marine reserve (Seychelles) has been an effectively protected no-take marine protected area (MPA) since 1968 and was shown in 1994 to support a healthy herbivorous fish assemblage. In 1998 Cousin Island reefs suffered extensive coral mortality following a coral bleaching event, and a phase shift from coral to algal dominance ensued. By 2005 mean coral cover was <1%, structural complexity had fallen and there had been a substantial increase in macroalgal cover, up to 40% in some areas. No clear trends were apparent in the overall numerical abundance and biomass of herbivorous fishes between 1994 and 2005, although smaller individuals became relatively scarce, most likely due to the loss of reef structure. Analysis of the feeding habits of six abundant and representative herbivorous fish species around Cousin Island in 2006 demonstrated that epilithic algae were the preferred food resource of all species and that macroalgae were avoided. Given the current dominance of macroalgae and the apparent absence of macroalgal consumers, it is suggested that the increasing abundance of macroalgae is reducing the probability of the system reverting to a coral dominated state.

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

PubMed

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

2011-01-01

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

High Macroalgal Cover and Low Coral Recruitment Undermines the Potential Resilience of the World's Southernmost Coral Reef Assemblages

PubMed Central

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

2011-01-01

Coral reefs are under increasing pressure from anthropogenic and climate-induced stressors. The ability of reefs to reassemble and regenerate after disturbances (i.e., resilience) is largely dependent on the capacity of herbivores to prevent macroalgal expansion, and the replenishment of coral populations through larval recruitment. Currently there is a paucity of this information for higher latitude, subtropical reefs. To assess the potential resilience of the benthic reef assemblages of Lord Howe Island (31°32′S, 159°04′E), the worlds' southernmost coral reef, we quantified the benthic composition, densities of juvenile corals (as a proxy for coral recruitment), and herbivorous fish communities. Despite some variation among habitats and sites, benthic communities were dominated by live scleractinian corals (mean cover 37.4%) and fleshy macroalgae (20.9%). Live coral cover was higher than in most other subtropical reefs and directly comparable to lower latitude tropical reefs. Juvenile coral densities (0.8 ind.m−2), however, were 5–200 times lower than those reported for tropical reefs. Overall, macroalgal cover was negatively related to the cover of live coral and the density of juvenile corals, but displayed no relationship with herbivorous fish biomass. The biomass of herbivorous fishes was relatively low (204 kg.ha−1), and in marked contrast to tropical reefs was dominated by macroalgal browsing species (84.1%) with relatively few grazing species. Despite their extremely low biomass, grazing fishes were positively related to both the density of juvenile corals and the cover of bare substrata, suggesting that they may enhance the recruitment of corals through the provision of suitable settlement sites. Although Lord Howe Islands' reefs are currently coral-dominated, the high macroalgal cover, coupled with limited coral recruitment and low coral growth rates suggest these reefs may be extremely susceptible to future disturbances. PMID:21991366

Farming behaviour of reef fishes increases the prevalence of coral disease associated microbes and black band disease

PubMed Central

Casey, Jordan M.; Ainsworth, Tracy D.; Choat, J. Howard; Connolly, Sean R.

2014-01-01

Microbial community structure on coral reefs is strongly influenced by coral–algae interactions; however, the extent to which this influence is mediated by fishes is unknown. By excluding fleshy macroalgae, cultivating palatable filamentous algae and engaging in frequent aggression to protect resources, territorial damselfish (f. Pomacentridae), such as Stegastes, mediate macro-benthic dynamics on coral reefs and may significantly influence microbial communities. To elucidate how Stegastes apicalis and Stegastes nigricans may alter benthic microbial assemblages and coral health, we determined the benthic community composition (epilithic algal matrix and prokaryotes) and coral disease prevalence inside and outside of damselfish territories in the Great Barrier Reef, Australia. 16S rDNA sequencing revealed distinct bacterial communities associated with turf algae and a two to three times greater relative abundance of phylotypes with high sequence similarity to potential coral pathogens inside Stegastes's territories. These potentially pathogenic phylotypes (totalling 30.04% of the community) were found to have high sequence similarity to those amplified from black band disease (BBD) and disease affected corals worldwide. Disease surveys further revealed a significantly higher occurrence of BBD inside S. nigricans's territories. These findings demonstrate the first link between fish behaviour, reservoirs of potential coral disease pathogens and the prevalence of coral disease. PMID:24966320

Unraveling the structure and composition of Varadero Reef, an improbable and imperiled coral reef in the Colombian Caribbean

PubMed Central

Rodríguez, Sara C.; López-Victoria, Mateo; Zapata, Fernando A.; Zea, Sven; Galindo-Martínez, Claudia T.; Iglesias-Prieto, Roberto; Pollock, Joseph; Medina, Mónica

2017-01-01

Coral reefs are commonly associated with oligotrophic, well-illuminated waters. In 2013, a healthy coral reef was discovered in one of the least expected places within the Colombian Caribbean: at the entrance of Cartagena Bay, a highly-polluted system that receives industrial and sewage waste, as well as high sediment and freshwater loads from an outlet of the Magdalena River (the longest and most populated river basin in Colombia). Here we provide the first characterization of Varadero Reef’s geomorphology and biological diversity. We also compare these characteristics with those of a nearby reference reef, Barú Reef, located in an area much less influenced by the described polluted system. Below the murky waters, we found high coral cover of 45.1% (±3.9; up to 80% in some sectors), high species diversity, including 42 species of scleractinian coral, 38 of sponge, three of lobster, and eight of sea urchin; a fish community composed of 61 species belonging to 24 families, and the typical zonation of a Caribbean fringing reef. All attributes found correspond to a reef that, according to current standards should be considered in “good condition”. Current plans to dredge part of Varadero threaten the survival of this reef. There is, therefore, an urgent need to describe the location and characteristics of Varadero as a first step towards gaining acknowledgement of its existence and garnering inherent legal and environmental protections. PMID:29259841

76 FR 20957 - Gulf of Mexico Fishery Management Council; Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-14

... Mexico Fishery Management Council's Red Drum, Reef Fish, Shrimp, Coral and Coral Reefs, and Stony Crab... Mexico Fishery Management Council's Red Drum, Reef Fish, Shrimp, Coral and Coral Reefs, and Stone Crab... to protect threatened staghorn and elkhorn corals, and requirements for gear marking of all spiny...

Expansion of corals on temperate reefs: direct and indirect effects of marine heatwaves

NASA Astrophysics Data System (ADS)

Tuckett, C. A.; de Bettignies, T.; Fromont, J.; Wernberg, T.

2017-09-01

Globally, many temperate marine communities have experienced significant temperature increases over recent decades in the form of gradual warming and heatwaves. As a result, these communities are shifting towards increasingly subtropical and tropical species compositions. Expanding coral populations have been reported from several temperate reef ecosystems along warming coastlines; these changes have been attributed to direct effects of gradual warming over decades. In contrast, increases in coral populations following shorter-term extreme warming events have rarely been documented. In this study, we compared coral populations on 17 temperate reefs in Western Australia before (2005/06) and after (2013) multiple marine heatwaves (2010-2012) affected the entire coastline. We hypothesised that coral communities would expand and change as a consequence of increasing local populations and recruitment of warm-affinity species. We found differences in coral community structure over time, driven primarily by a fourfold increase of one local species, Plesiastrea versipora, rather than recruitment of warm-affinity species. Coral populations became strongly dominated by small size classes, indicative of recent increased recruitment or recruit survival. These changes were likely facilitated by competitive release of corals from dominant temperate seaweeds, which perished during the heatwaves, rather than driven by direct temperature effects. Overall, as corals are inherently warm-water taxa not commonly associated with seaweed-dominated temperate reefs, these findings are consistent with a net tropicalisation. Our study draws attention to processes other than gradual warming that also influence the trajectory of temperate reefs in a changing ocean.

The impact of exploiting grazers (Scaridae) on the dynamics of Caribbean coral reefs.

PubMed

Mumby, Peter J

2006-04-01

Coral reefs provide a number of ecosystem services including coastal defense from storms, the generation of building materials, and fisheries. It is increasingly clear that the management of reef resources requires an ecosystem approach in which extractive activities are weighed against the needs of the ecosystem and its functions rather than solely those of the fishery. Here, I use a spatially explicit simulation model of a Caribbean coral reef to examine the ecosystem requirements for grazing which is primarily conducted by parrotfishes (Scaridae). The model allows the impact of fishing grazers to be assessed in the wider context of other ecosystem processes including coral-algal competition, hurricanes, and mass extinction of the herbivorous urchin Diadema antillarum. Using a new analytical model of scarid grazing, it is estimated that parrotfishes can only maintain between 10% and 30% of a structurally complex forereef in a grazed state. Predictions from this grazing model were then incorporated into a broader simulation model of the ecosystem. Simulations predict that scarid grazing is unable to maintain high levels of coral cover (> or = 30%) when severe hurricanes occur on a decadal basis, such as occurs in parts of the northern Caribbean. However, reefs can withstand such intense disturbance when grazing is undertaken by both scarids and the urchin Diadema. Scarid grazing is predicted to allow recovery from hurricanes when their incidence falls to 20 years or less (e.g., most of Central and South America). Sensitivity analyses revealed that scarid grazing had the most acute impact on model behavior, and depletion led to the emergence of a stable, algal-dominated community state. Under conditions of heavy grazer depletion, coral cover was predicted to decline rapidly from an initial level of 30% to less than 1% within 40 years, even when hurricane frequency was low at 60 years. Depleted grazers caused a population bottleneck in juvenile corals in which algal overgrowth caused elevated levels of postsettlement mortality and resulted in a bimodal distribution of coral sizes. Several new hypotheses were generated including a region-wide change in the spatial heterogeneity of coral reefs following extinction of Diadema. The management of parrotfishes on Caribbean reefs is usually approached implicitly through no-take marine reserves. The model predicts that depletion of grazers in nonreserve areas can severely limit coral accretion. Other studies have shown that low coral accretion can reduce the structural complexity and therefore quality of the reef habitat for many organisms. A speculative yet rational inference from the model is that failure to manage scarid populations outside reserves will have a profoundly negative impact on the functioning of the reserve system and status of non-reserve reefs.

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. © 2016 John Wiley & Sons Ltd.

A study on the recovery of Tobago's coral reefs following the 2010 mass bleaching event.

PubMed

Buglass, Salome; Donner, Simon D; Alemu I, Jahson B

2016-03-15

In 2010, severe coral bleaching was observed across the southeastern Caribbean, including the island of Tobago, where coral reefs are subject to sedimentation and high nutrient levels from terrestrial runoff. Here we examine changes in corals' colony size distributions over time (2010-2013), juvenile abundances and sedimentation rates for sites across Tobago following the 2010 bleaching event. The results indicated that since pre-bleaching coral cover was already low due to local factors and past disturbance, the 2010 event affected only particular susceptible species' population size structure and increased the proportion of small sized colonies. The low density of juveniles (mean of 5.4±6.3 juveniles/m(-2)) suggests that Tobago's reefs already experienced limited recruitment, especially of large broadcasting species. The juvenile distribution and the response of individual species to the bleaching event support the notion that Caribbean reefs are becoming dominated by weedy non-framework building taxa which are more resilient to disturbances. Copyright © 2016 Elsevier Ltd. All rights reserved.

Atoll-scale patterns in coral reef community structure: Human signatures on Ulithi Atoll, Micronesia.

PubMed

Crane, Nicole L; Nelson, Peter; Abelson, Avigdor; Precoda, Kristin; Rulmal, John; Bernardi, Giacomo; Paddack, Michelle

2017-01-01

The dynamic relationship between reefs and the people who utilize them at a subsistence level is poorly understood. This paper characterizes atoll-scale patterns in shallow coral reef habitat and fish community structure, and correlates these with environmental characteristics and anthropogenic factors, critical to conservation efforts for the reefs and the people who depend on them. Hierarchical clustering analyses by site for benthic composition and fish community resulted in the same 3 major clusters: cluster 1-oceanic (close proximity to deep water) and uninhabited (low human impact); cluster 2-oceanic and inhabited (high human impact); and cluster 3-lagoonal (facing the inside of the lagoon) and inhabited (highest human impact). Distance from village, reef exposure to deep water and human population size had the greatest effect in predicting the fish and benthic community structure. Our study demonstrates a strong association between benthic and fish community structure and human use across the Ulithi Atoll (Yap State, Federated States of Micronesia) and confirms a pattern observed by local people that an 'opportunistic' scleractinian coral (Montipora sp.) is associated with more highly impacted reefs. Our findings suggest that small human populations (subsistence fishing) can nevertheless have considerable ecological impacts on reefs due, in part, to changes in fishing practices rather than overfishing per se, as well as larger global trends. Findings from this work can assist in building local capacity to manage reef resources across an atoll-wide scale, and illustrates the importance of anthropogenic impact even in small communities.

Suitable Environmental Ranges for Potential Coral Reef Habitats in the Tropical Ocean

PubMed Central

Guan, Yi; Hohn, Sönke; Merico, Agostino

2015-01-01

Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7—29.6 °C for temperature, 28.7—40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed. PMID:26030287

Suitable environmental ranges for potential coral reef habitats in the tropical ocean.

PubMed

Guan, Yi; Hohn, Sönke; Merico, Agostino

2015-01-01

Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7-29.6 °C for temperature, 28.7-40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed.

Framework of barrier reefs threatened by ocean acidification.

PubMed

Comeau, Steeve; Lantz, Coulson A; Edmunds, Peter J; Carpenter, Robert C

2016-03-01

To date, studies of ocean acidification (OA) on coral reefs have focused on organisms rather than communities, and the few community effects that have been addressed have focused on shallow back reef habitats. The effects of OA on outer barrier reefs, which are the most striking of coral reef habitats and are functionally and physically different from back reefs, are unknown. Using 5-m long outdoor flumes to create treatment conditions, we constructed coral reef communities comprised of calcified algae, corals, and reef pavement that were assembled to match the community structure at 17 m depth on the outer barrier reef of Moorea, French Polynesia. Communities were maintained under ambient and 1200 μatm pCO2 for 7 weeks, and net calcification rates were measured at different flow speeds. Community net calcification was significantly affected by OA, especially at night when net calcification was depressed ~78% compared to ambient pCO2 . Flow speed (2-14 cm s(-1) ) enhanced net calcification only at night under elevated pCO2 . Reef pavement also was affected by OA, with dissolution ~86% higher under elevated pCO2 compared to ambient pCO2 . These results suggest that net accretion of outer barrier reef communities will decline under OA conditions predicted within the next 100 years, largely because of increased dissolution of reef pavement. Such extensive dissolution poses a threat to the carbonate foundation of barrier reef communities. © 2015 John Wiley & Sons Ltd.

Doom and boom on a resilient reef: climate change, algal overgrowth and coral recovery.

PubMed

Diaz-Pulido, Guillermo; McCook, Laurence J; Dove, Sophie; Berkelmans, Ray; Roff, George; Kline, David I; Weeks, Scarla; Evans, Richard D; Williamson, David H; Hoegh-Guldberg, Ove

2009-01-01

Coral reefs around the world are experiencing large-scale degradation, largely due to global climate change, overfishing, diseases and eutrophication. Climate change models suggest increasing frequency and severity of warming-induced coral bleaching events, with consequent increases in coral mortality and algal overgrowth. Critically, the recovery of damaged reefs will depend on the reversibility of seaweed blooms, generally considered to depend on grazing of the seaweed, and replenishment of corals by larvae that successfully recruit to damaged reefs. These processes usually take years to decades to bring a reef back to coral dominance. In 2006, mass bleaching of corals on inshore reefs of the Great Barrier Reef caused high coral mortality. Here we show that this coral mortality was followed by an unprecedented bloom of a single species of unpalatable seaweed (Lobophora variegata), colonizing dead coral skeletons, but that corals on these reefs recovered dramatically, in less than a year. Unexpectedly, this rapid reversal did not involve reestablishment of corals by recruitment of coral larvae, as often assumed, but depended on several ecological mechanisms previously underestimated. These mechanisms of ecological recovery included rapid regeneration rates of remnant coral tissue, very high competitive ability of the corals allowing them to out-compete the seaweed, a natural seasonal decline in the particular species of dominant seaweed, and an effective marine protected area system. Our study provides a key example of the doom and boom of a highly resilient reef, and new insights into the variability and mechanisms of reef resilience under rapid climate change.

Application of Landscape Mosaic Technology to Complement Coral Reef Resource Mapping and Monitoring

DTIC Science & Technology

2010-10-01

irregular shapes pose a challenge for divers trying to delimit live tissue boundaries. Future improvements in the 3D representation of benthic mosaics...benthic habitats can be especially challenging when the spatial extent of injuries exceeds tens of square meters. These large injuries are often too...the impacts of severe physical disturbance on coral reefs can be especially challenging when large-scale modifications to the reef structure takes

Genetic structure of coral-Symbiodinium symbioses on the world's warmest reefs.

PubMed

Smith, Edward G; Hume, Benjamin C C; Delaney, Patrice; Wiedenmann, Jörg; Burt, John A

2017-01-01

Corals in the Arabian/Persian Gulf (PAG) survive extreme sea temperatures (summer mean: >34°C), and it is unclear whether these corals have genetically adapted or physiologically acclimated to these conditions. In order to elucidate the processes involved in the thermal tolerance of PAG corals, it is essential to understand the connectivity between reefs within and outside of the PAG. To this end, this study set out to investigate the genetic structure of the coral, Platygyra daedalea, and its symbiotic algae in the PAG and neighbouring Gulf of Oman. Using nuclear markers (the ITS region and an intron of the Pax-C gene), this study demonstrates genetic divergence of P. daedalea on reefs within the thermally extreme PAG compared with those in the neighbouring Gulf of Oman. Isolation by distance of P. daedalea was supported by the ITS dataset but not the Pax-C intron. In addition, the symbiont community within the PAG was dominated by C3 symbionts, while the purportedly thermotolerant clade D was extremely rare and was common only at sites outside of the PAG. Analysis of the psbAncr indicates that the C3 variant hosted by P. daedalea in the PAG belongs to the newly described species, Symbiodinium thermophilum. The structuring of the coral and symbiont populations suggests that both partners of the symbiosis may contribute to the high bleaching thresholds of PAG corals. While limited gene flow has likely played a role in local adaptation within the PAG, it also indicates limited potential for natural export of thermal tolerance traits to reefs elsewhere in the Indian Ocean threatened by climate change.

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 the future. PMID:24983747

Patterns in reef fish assemblages: Insights from the Chagos Archipelago

PubMed Central

Roche, Ronan; Koldewey, Heather; Turner, John

2018-01-01

Understanding the drivers of variability in the composition of fish assemblages across the Indo-Pacific region is crucial to support coral reef ecosystem resilience. Whilst numerous relationships and feedback mechanisms between the functional roles of coral reef fishes and reef benthic composition have been investigated, certain key groups, such as the herbivores, are widely suggested to maintain reefs in a coral-dominated state. Examining links between fishes and reef benthos is complicated by the interactions between natural processes, disturbance events and anthropogenic impacts, particularly fishing pressure. This study examined fish assemblages and associated benthic variables across five atolls within the Chagos Archipelago, where fishing pressure is largely absent, to better understand these relationships. We found high variability in fish assemblages among atolls and sites across the archipelago, especially for key groups such as a suite of grazer-detritivore surgeonfish, and the parrotfishes which varied in density over 40-fold between sites. Differences in fish assemblages were significantly associated with variable levels of both live and recently dead coral cover and rugosity. We suggest these results reflect differing coral recovery trajectories following coral bleaching events and a strong influence of ‘bottom-up’ control mechanisms on fish assemblages. Species level analyses revealed that Scarus niger, Acanthurus nigrofuscus and Chlorurus strongylocephalos were key species driving differences in fish assemblage structure. Clarifying the trophic roles of herbivorous and detritivorous reef fishes will require species-level studies, which also examine feeding behaviour, to fully understand their contribution in maintaining reef resilience to climate change and fishing impacts. PMID:29351566

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

76 FR 66021 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Generic Annual Catch Limits...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-25

..., Shrimp, and Coral and Coral Reefs Fishery Management Plans for the Gulf of Mexico (FMPs) as prepared and... fisheries for reef fish, red drum, shrimp, and coral and coral reefs of the Gulf of Mexico (Gulf) are... remove octocorals from the Coral and Coral Reefs FMP. Most octocorals are harvested in waters under the...

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

...-Grouper Fishery Off the Southern Atlantic States and Coral and Coral Reefs Fishery in the South Atlantic... the South Atlantic Region and the FMP for Coral, Coral Reefs, and Live/Hard Bottom Habitats of the... Aquariums to collect, with certain conditions, various species of reef fish and live rock in Federal waters...

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

2017-09-01

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. © 2017 John Wiley & Sons Ltd.

Clypeotheca, a new skeletal structure in scleractinian corals: a potential stress indicator

NASA Astrophysics Data System (ADS)

Nothdurft, L. D.; Webb, G. E.

2009-03-01

Physiological responses to environmental stress are increasingly well studied in scleractinian corals. This work reports a new stress-related skeletal structure we term clypeotheca. Clypeotheca was observed in several live-collected common reef-building coral genera and a two to three kya subfossil specimen from Heron Reef, Great Barrier Reef and consists of an epitheca-like skeletal wall that seals over the surface of parts of the corallum in areas of stress or damage. It appears to form from a coordinated process wherein neighboring polyps and adjoining coenosarc seal themselves off from the surrounding environment as they contract and die. Clypeotheca forms from inward skeletal centripetal growth at the edges of corallites and by the merging of flange-like outgrowths that surround individual spines over the surface of the coenosteum. Microstructurally, the merged flanges are similar to upside-down dissepiments and true epitheca. Clypeotheca is interpreted primarily as a response to stress that may help protect the colony from invasion of unhealthy tissues by parasites or disease by retracting tissues in areas that have become unhealthy for the polyps. Identification of skeletal responses of corals to environmental stress may enable the frequency of certain types of environmental stress to be documented in past environments. Such data may be important for understanding the nature of reef dynamics through intervals of climate change and for monitoring the effects of possible anthropogenic stress in modern coral reef habitats.

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

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.

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.

A Global Estimate of the Number of Coral Reef Fishers

PubMed Central

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. PMID:23840327

Snapping shrimp sound production patterns on Caribbean coral reefs: relationships with celestial cycles and environmental variables

NASA Astrophysics Data System (ADS)

Lillis, Ashlee; Mooney, T. Aran

2018-06-01

The rich acoustic environment of coral reefs, including the sounds of a variety of fish and invertebrates, is a reflection of the structural complexity and biological diversity of these habitats. Emerging interest in applying passive acoustic monitoring and soundscape analysis to measure coral reef habitat characteristics and track ecological patterns is hindered by a poor understanding of the most common and abundant sound producers on reefs—the snapping shrimp. Here, we sought to address several basic biophysical drivers of reef sound by investigating acoustic activity patterns of snapping shrimp populations on two adjacent coral reefs using a detailed snap detection analysis routine to a high-resolution 2.5-month acoustic dataset from the US Virgin Islands. The reefs exhibited strong diel and lunar periodicity in snap rates and clear spatial differences in snapping levels. Snap rates peaked at dawn and dusk and were higher overall during daytime versus nighttime, a seldom-reported pattern in earlier descriptions of diel snapping shrimp acoustic activity. Small differences between the sites in snap rate rhythms were detected and illustrate how analyses of specific soundscape elements might reveal subtle between-reef variation. Snap rates were highly correlated with environmental variables, including water temperature and light, and were found to be sensitive to changes in oceanographic forcing. This study further establishes snapping shrimp as key players in the coral reef chorus and provides evidence that their acoustic output reflects a combination of environmental conditions, celestial influences, and spatial habitat variation. Effective application of passive acoustic monitoring in coral reef habitats using snap rates or snapping-influenced acoustic metrics will require a mechanistic understanding of the underlying spatial and temporal variation in snapping shrimp sound production across multiple scales.

Identifying multiple coral reef regimes and their drivers across the Hawaiian archipelago

PubMed Central

Jouffray, Jean-Baptiste; Nyström, Magnus; Norström, Albert V.; Williams, Ivor D.; Wedding, Lisa M.; Kittinger, John N.; Williams, Gareth J.

2015-01-01

Loss of coral reef resilience can lead to dramatic changes in benthic structure, often called regime shifts, which significantly alter ecosystem processes and functioning. In the face of global change and increasing direct human impacts, there is an urgent need to anticipate and prevent undesirable regime shifts and, conversely, to reverse shifts in already degraded reef systems. Such challenges require a better understanding of the human and natural drivers that support or undermine different reef regimes. The Hawaiian archipelago extends across a wide gradient of natural and anthropogenic conditions and provides us a unique opportunity to investigate the relationships between multiple reef regimes, their dynamics and potential drivers. We applied a combination of exploratory ordination methods and inferential statistics to one of the most comprehensive coral reef datasets available in order to detect, visualize and define potential multiple ecosystem regimes. This study demonstrates the existence of three distinct reef regimes dominated by hard corals, turf algae or macroalgae. Results from boosted regression trees show nonlinear patterns among predictors that help to explain the occurrence of these regimes, and highlight herbivore biomass as the key driver in addition to effluent, latitude and depth.

Mangroves enhance the biomass of coral reef fish communities in the Caribbean.

PubMed

Mumby, Peter J; Edwards, Alasdair J; Arias-González, J Ernesto; Lindeman, Kenyon C; Blackwell, Paul G; Gall, Angela; Gorczynska, Malgosia I; Harborne, Alastair R; Pescod, Claire L; Renken, Henk; Wabnitz, Colette C C; Llewellyn, Ghislane

2004-02-05

Mangrove forests are one of the world's most threatened tropical ecosystems with global loss exceeding 35% (ref. 1). Juvenile coral reef fish often inhabit mangroves, but the importance of these nurseries to reef fish population dynamics has not been quantified. Indeed, mangroves might be expected to have negligible influence on reef fish communities: juvenile fish can inhabit alternative habitats and fish populations may be regulated by other limiting factors such as larval supply or fishing. Here we show that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish. Mangroves in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs. In addition, the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves. The largest herbivorous fish in the Atlantic, Scarus guacamaia, has a functional dependency on mangroves and has suffered local extinction after mangrove removal. Current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function, fisheries productivity and resilience of reefs. Conservation efforts should protect connected corridors of mangroves, seagrass beds and coral reefs.

Mangroves enhance the biomass of coral reef fish communities in the Caribbean

NASA Astrophysics Data System (ADS)

Mumby, Peter J.; Edwards, Alasdair J.; Ernesto Arias-González, J.; Lindeman, Kenyon C.; Blackwell, Paul G.; Gall, Angela; Gorczynska, Malgosia I.; Harborne, Alastair R.; Pescod, Claire L.; Renken, Henk; C. C. Wabnitz, Colette; Llewellyn, Ghislane

2004-02-01

Mangrove forests are one of the world's most threatened tropical ecosystems with global loss exceeding 35% (ref. 1). Juvenile coral reef fish often inhabit mangroves, but the importance of these nurseries to reef fish population dynamics has not been quantified. Indeed, mangroves might be expected to have negligible influence on reef fish communities: juvenile fish can inhabit alternative habitats and fish populations may be regulated by other limiting factors such as larval supply or fishing. Here we show that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish. Mangroves in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs. In addition, the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves. The largest herbivorous fish in the Atlantic, Scarus guacamaia, has a functional dependency on mangroves and has suffered local extinction after mangrove removal. Current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function, fisheries productivity and resilience of reefs. Conservation efforts should protect connected corridors of mangroves, seagrass beds and coral reefs.

Predator-prey interactions between the corallivorous snail Coralliophila abbreviata and the carnivorous deltoid rock snail Thais deltoidea.

PubMed

Sharp, William C; Delgado, Gabriel A

2015-10-01

Coral reefs in the Florida Keys have become highly degraded in recent decades, prompting efforts to reestablish populations of vital reef-accreting corals to restore reef structure and ecological function. However, predation on these corals by the corallivorous gastropod Coralliophila abbreviata has been a substantial and chronic impediment to these restoration efforts. We conducted laboratory experiments to determine whether Thais deltoidea, a carnivorous gastropod that commonly occurs with C. abbreviata, is a predator of C. abbreviata. We demonstrated that T. deltoidea readily preys upon C. abbreviata and preferentially targets smaller individuals, a foraging behavior that may optimize the energy gained due to reduced handling and consumption times. If this trophic relationship proves ecologically relevant, understanding the predator-prey dynamics between these species could ultimately aid in the development of a comprehensive coral reef restoration strategy for Florida.

Hysteresis in coral reefs under macroalgal toxicity and overfishing.

PubMed

Bhattacharyya, Joydeb; Pal, Samares

2015-03-01

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

Virus-host interactions and their roles in coral reef health and disease.

PubMed

Thurber, Rebecca Vega; Payet, Jérôme P; Thurber, Andrew R; Correa, Adrienne M S

2017-04-01

Coral reefs occur in nutrient-poor shallow waters, constitute biodiversity and productivity hotspots, and are threatened by anthropogenic disturbance. This Review provides an introduction to coral reef virology and emphasizes the links between viruses, coral mortality and reef ecosystem decline. We describe the distinctive benthic-associated and water-column- associated viromes that are unique to coral reefs, which have received less attention than viruses in open-ocean systems. We hypothesize that viruses of bacteria and eukaryotes dynamically interact with their hosts in the water column and with scleractinian (stony) corals to influence microbial community dynamics, coral bleaching and disease, and reef biogeochemical cycling. Last, we outline how marine viruses are an integral part of the reef system and suggest that the influence of viruses on reef function is an essential component of these globally important environments.

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 or...

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 or...

40 CFR 230.44 - Coral reefs.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Coral reefs. 230.44 Section 230.44... Aquatic Sites § 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually of calcareous... organisms present in growing portions of the reef. (b) Possible loss of values: The discharge of dredged or...

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 or...

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 or...

76 FR 18775 - Pacific Remote Islands Marine National Monument; Monument Management Plan, Comprehensive...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-05

... equator. These areas have deep-water corals, coral reefs, corals in near-pristine condition, and predator... will be revised as needed. Kingman Reef and Palmyra Atoll have relatively undisturbed coral reefs, with the highest levels of coral diversity in the central Pacific Ocean. Kingman Reef has the greatest...

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

PubMed

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

2014-05-05

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

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

PubMed Central

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

2016-01-01

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. PMID:26740019

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cross, S.L.; Lighty, R.G.

Coral-rudist reefs of the Lower Cretaceous Mural limestone, southeastern Arizona, show a pronounced relationship between specific reef facies, primary porosity, and early submarine diagenesis. These large open-shelf reefs differ from the well-studied low-relief rudist buildups, and provide an alternate analog for many Cretaceous reef reservoirs. Arizona buildups have diverse corals, high depositional relief, and a well-developed facies zonation from fore reef to back reef: skeletal grainstone talus, muddy fore reef with branching and lamellar corals, massive reef crest with abundant lamellar corals and sandy matrix, protected thickets of delicate branching corals and large rudist mounds, and a wide sediment apronmore » of well-washed coral, rudist, and benthic foraminiferal sands. These well-exposed outcrops permit a detailed facies comparison of primary interparticle porosity. Porosity as high as 40% in grainstones was occluded by later subsurface cements. Reef-framework interparticle porosity was negligible because fore-reef coral and back-reef rudist facies were infilled by muds, and high-energy reef-crest frameworks were filled by peloidal submarine cement crusts and muddy skeletal sands. These thick crusts coated lamellar corals in cryptic and open reef-crest areas, and are laminated with ripple and draped bed forms that suggest current influence. Similar peloidal crusts and laminated textures are common magnesium-calcite submarine cement features in modern reefs. By documenting specific facies control on early cementation and textural variability, patterns of late-stage subsurface diagenesis and secondary porosity may be more easily explained for Cretaceous reef reservoirs. Significant primary porosity might be retained between sands in back-reef facies and within coral skeletons.« less

Farming behaviour of reef fishes increases the prevalence of coral disease associated microbes and black band disease.

PubMed

Casey, Jordan M; Ainsworth, Tracy D; Choat, J Howard; Connolly, Sean R

2014-08-07

Microbial community structure on coral reefs is strongly influenced by coral-algae interactions; however, the extent to which this influence is mediated by fishes is unknown. By excluding fleshy macroalgae, cultivating palatable filamentous algae and engaging in frequent aggression to protect resources, territorial damselfish (f. Pomacentridae), such as Stegastes, mediate macro-benthic dynamics on coral reefs and may significantly influence microbial communities. To elucidate how Stegastes apicalis and Stegastes nigricans may alter benthic microbial assemblages and coral health, we determined the benthic community composition (epilithic algal matrix and prokaryotes) and coral disease prevalence inside and outside of damselfish territories in the Great Barrier Reef, Australia. 16S rDNA sequencing revealed distinct bacterial communities associated with turf algae and a two to three times greater relative abundance of phylotypes with high sequence similarity to potential coral pathogens inside Stegastes's territories. These potentially pathogenic phylotypes (totalling 30.04% of the community) were found to have high sequence similarity to those amplified from black band disease (BBD) and disease affected corals worldwide. Disease surveys further revealed a significantly higher occurrence of BBD inside S. nigricans's territories. These findings demonstrate the first link between fish behaviour, reservoirs of potential coral disease pathogens and the prevalence of coral disease. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

The Coral Reef pH-stat: An Important Defense Against Ocean Acidification? (Invited)

NASA Astrophysics Data System (ADS)

Andersson, A. J.; Yeakel, K.; Bates, N.; de Putron, S.; Collins, A.

2013-12-01

Concerns have been raised on how coral reefs will be affected by ocean acidification (OA), but there are currently no direct predictions on how seawater CO2 chemistry and pH within coral reefs might change in response to OA. Projections of future changes in seawater pH and aragonite saturation state have only been applied to open ocean conditions surrounding coral reef environments rather than the reef systems themselves. The seawater CO2 chemistry within heterogenous coral reef systems can be significantly different from that of the open ocean depending on the residence time, community composition and the major biogeochemical processes occurring on the reef, i.e., net ecosystem organic carbon production and calcification, which combined act to modify the seawater chemistry. We argue that these processes and coral reefs in general could as a pH-stat, partly regulating seawater pH on the reef and offsetting changes in seawater chemistry imposed by ocean acidification. Based on observations from the Bermuda coral reef, we show that a range of anticipated biogeochemical responses of coral reef communities to OA by the end of this century could partially offset changes in seawater pH by an average of 12% to 24%.

The Role of Turtles as Coral Reef Macroherbivores

PubMed Central

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. PMID:22768189

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.

Coral recovery in the central Maldives archipelago since the last major mass-bleaching, in 1998

NASA Astrophysics Data System (ADS)

Pisapia, C.; Burn, D.; Yoosuf, R.; Najeeb, A.; Anderson, K. D.; Pratchett, M. S.

2016-10-01

Increasing frequency and severity of disturbances is causing global degradation of coral reef ecosystems. This study examined temporal changes in live coral cover and coral composition in the central Maldives from 1997 to 2016, encompassing two bleaching events, a tsunami, and an outbreak of Acanthaster planci. We also examined the contemporary size structure for five dominant coral taxa (tabular Acropora, Acropora muricata, Acropora humilis, Pocillopora spp, and massive Porites). Total coral cover increased throughout the study period, with marked increases following the 1998 mass-bleaching. The relative abundance of key genera has changed through time, where Acropora and Pocillopora (which are highly susceptible to bleaching) were under-represented following 1998 mass-bleaching but increased until outbreaks of A. planci in 2015. The contemporary size-structure for all coral taxa was dominated by larger colonies with peaked distributions suggesting that recent disturbances had a disproportionate impact on smaller colonies, or that recruitment is currently limited. This may suggest that coral resilience has been compromised by recent disturbances, and further bleaching (expected in 2016) could lead to highly protracted recovery times. We showed that Maldivian reefs recovered following the 1998 mass-bleaching event, but it took up to a decade, and ongoing disturbances may be eroding reef resilience.

Coral recovery in the central Maldives archipelago since the last major mass-bleaching, in 1998.

PubMed

Pisapia, C; Burn, D; Yoosuf, R; Najeeb, A; Anderson, K D; Pratchett, M S

2016-10-03

Increasing frequency and severity of disturbances is causing global degradation of coral reef ecosystems. This study examined temporal changes in live coral cover and coral composition in the central Maldives from 1997 to 2016, encompassing two bleaching events, a tsunami, and an outbreak of Acanthaster planci. We also examined the contemporary size structure for five dominant coral taxa (tabular Acropora, Acropora muricata, Acropora humilis, Pocillopora spp, and massive Porites). Total coral cover increased throughout the study period, with marked increases following the 1998 mass-bleaching. The relative abundance of key genera has changed through time, where Acropora and Pocillopora (which are highly susceptible to bleaching) were under-represented following 1998 mass-bleaching but increased until outbreaks of A. planci in 2015. The contemporary size-structure for all coral taxa was dominated by larger colonies with peaked distributions suggesting that recent disturbances had a disproportionate impact on smaller colonies, or that recruitment is currently limited. This may suggest that coral resilience has been compromised by recent disturbances, and further bleaching (expected in 2016) could lead to highly protracted recovery times. We showed that Maldivian reefs recovered following the 1998 mass-bleaching event, but it took up to a decade, and ongoing disturbances may be eroding reef resilience.

Coral recovery in the central Maldives archipelago since the last major mass-bleaching, in 1998

PubMed Central

Pisapia, C.; Burn, D.; Yoosuf, R.; Najeeb, A.; Anderson, K. D.; Pratchett, M. S.

2016-01-01

Increasing frequency and severity of disturbances is causing global degradation of coral reef ecosystems. This study examined temporal changes in live coral cover and coral composition in the central Maldives from 1997 to 2016, encompassing two bleaching events, a tsunami, and an outbreak of Acanthaster planci. We also examined the contemporary size structure for five dominant coral taxa (tabular Acropora, Acropora muricata, Acropora humilis, Pocillopora spp, and massive Porites). Total coral cover increased throughout the study period, with marked increases following the 1998 mass-bleaching. The relative abundance of key genera has changed through time, where Acropora and Pocillopora (which are highly susceptible to bleaching) were under-represented following 1998 mass-bleaching but increased until outbreaks of A. planci in 2015. The contemporary size-structure for all coral taxa was dominated by larger colonies with peaked distributions suggesting that recent disturbances had a disproportionate impact on smaller colonies, or that recruitment is currently limited. This may suggest that coral resilience has been compromised by recent disturbances, and further bleaching (expected in 2016) could lead to highly protracted recovery times. We showed that Maldivian reefs recovered following the 1998 mass-bleaching event, but it took up to a decade, and ongoing disturbances may be eroding reef resilience. PMID:27694823

Primary production of coral ecosystems in the Vietnamese coastal and adjacent marine waters

NASA Astrophysics Data System (ADS)

Tac-An, Nguyen; Minh-Thu, Phan; Cherbadji, I. I.; Propp, M. V.; Odintsov, V. S.; Propp, L. H.

2013-11-01

Coral reef ecosystems in coastal waters and islands of Vietnam have high primary production. Average gross primary production (GPP) in coral reef waters was 0.39 g C m-2 day-1. GPP of corals ranged from 3.12 to 4.37 g C m-2 day-1. GPP of benthic microalgae in coral reefs ranged from 2 to 10 g C m-2 day-1. GPP of macro-algae was 2.34 g C m-2 day-1. Therefore, the total of GPP of whole coral reef ecosystems could reach 7.85 to 17.10 g C m-2 day-1. Almost all values of the ratio of photosynthesis to respiration in the water bodies are higher than 1, which means these regions are autotrophic systems. Wire variation of GPP in coral reefs was contributed by species abundance of coral and organisms, nutrient supports and environmental characteristics of coral ecosystems. Coral reefs play an important ecological role of biogeochemical cycling of nutrients in waters around the reefs. These results contribute valuable information for the protection, conservation and sustainable exploitation of the natural resources in coral reef ecosystems in Vietnam.

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...

Species-area relationships in coral communities: evaluating mechanisms for a commonly observed pattern

NASA Astrophysics Data System (ADS)

Huntington, B. E.; Lirman, D.

2012-12-01

Landscape-scale attributes of patch size, spatial isolation, and topographic complexity are known to influence diversity and abundance in terrestrial and marine systems, but remain collectively untested for reef-building corals. To investigate the relationship between the coral assemblage and seascape variation in reef habitats, we took advantage of the distinct boundaries, spatial configurations, and topographic complexities among artificial reef patches to overcome the difficulties of manipulating natural reefs. Reef size (m2) was found to be the foremost predictor of coral richness in accordance with species-area relationship predictions. Larger reefs were also found to support significantly higher colony densities, enabling us to reject the null hypothesis of random placement (a sampling artifact) in favor of target area predictions that suggest greater rates of immigration on larger reefs. Unlike the pattern previously documented for reef fishes, topographic complexity was not a significant predictor of any coral assemblage response variable, despite the range of complexity values sampled. Lastly, coral colony density was best explained by both increasing reef size and decreasing reef spatial isolation, a pattern found exclusively among brooding species with shorter larval dispersal distances. We conclude that seascape attributes of reef size and spatial configuration within the seascape can influence the species richness and abundance of the coral community at relatively small spatial scales (<1 km). Specifically, we demonstrate how patterns in the coral communities that have naturally established on these manipulated reefs agree with the target area and island biogeography mechanisms to drive species-area relationships in reef-building corals. Based on the patterns documented in artificial reefs, habitat degradation that results in smaller, more isolated natural reefs may compromise coral diversity.

Stable isotopes reveal spatial variability in the trophic structure of a macro-benthic invertebrate community in a tropical coral reef.

PubMed

Kolasinski, Joanna; Nahon, Sarah; Rogers, Karyne; Chauvin, Anne; Bigot, Lionel; Frouin, Patrick

2016-02-15

Studies of organic matter fluxes in coral reefs are historically based on physical and biogeochemical approaches. It is important to link these approaches to community analysis as the abundance and behaviour of species, populations or trophic groups can have a profound effect on nutrient budgets. We determined the carbon and nitrogen isotopic compositions of coral reef organic matter sources and macro-benthic invertebrate communities using a Europa Geo 20/20 isotope ratio mass spectrometer interfaced to an ANCA-SL elemental analyzer in continuous flow mode. Isotopic ecology metrics and a mixing model were used to analyze and interpret the data. The coral reef macro-invertebrate community principally relies on detrital or recycled food sources. An increased reliance on reef nitrogen-derived sources was observed in the cold-dry season. The community food-web lengths differ noticeably across the coral reef and reflect the characteristics and origin of organic matter reservoirs. Anthropogenic and terrestrial inputs lead to a loss of biological diversity. Exclusive dominance of suspension-feeding species is observed in areas receiving direct surface riverine particulate organic matter. The accumulation of sediment organic matter in eutrophic areas leads to dominance of deposit-feeding species. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

[Structure of reef fish communities in Catalinas Islands and Ocotal beach, North Pacific of Costa Rica].

PubMed

Espinoza, Mario; Salas, Eva

2005-01-01

The reefs are heterogeneous systems that maintain a high diversity of organisms. Fish community structure varies within and among reefs, so it would be expected that reef structure and heterogeneity should affect fish communities inhabiting reefs. Four reef patches at Catalinas Islands (Sur, La Pared, Roca Sucia and Sombrero) and one in Ocotal beach (10 degrees 28'45" N; 85 degrees 52'35" W) were studied with visual censuses (July-December 2003). The structure and composition of fishes between Catalinas islands and Ocotal beach were different, and habitat structure and composition explain most of the variance founded. The presence of the fleshy algae Caulerpa sertularioides in Ocotal, and the corals Tubastrea coccinea and Pocillopora spp. at Catalinas Island explained the variability among sites and how it affected fish community structure and composition. The butterfly fish Johnrandallia nigrirostris, damselfish Microspathodon dorsalis, and surgeon fish Prionurus punctatus were directly correlated with the ahermatipic coral Tubastrea coccinea in Roca Sucia reef, while the angel fish Holacanthus passer was associated to reefs with a major percentage of rocky substrate. Other species such as the damselfish Abudefduf troschelli and Halichoeres dispilus were more abundant at Ocotal, where the algae C sertularioides dominated. The number and abundance of reef fishes was directly correlated with the rugosity index at the reefs of Roca Sucia and Ocotal, but not at reefs of La Pared and Sombrero.

Restricted gene flow and local adaptation highlight the vulnerability of high-latitude reefs to rapid environmental change.

PubMed

Thomas, Luke; Kennington, W Jason; Evans, Richard D; Kendrick, Gary A; Stat, Michael

2017-06-01

Global climate change poses a serious threat to the future health of coral reef ecosystems. This calls for management strategies that are focused on maximizing the evolutionary potential of coral reefs. Fundamental to this is an accurate understanding of the spatial genetic structure in dominant reef-building coral species. In this study, we apply a genotyping-by-sequencing approach to investigate genome-wide patterns of genetic diversity, gene flow, and local adaptation in a reef-building coral, Pocillopora damicornis, across 10 degrees of latitude and a transition from temperate to tropical waters. We identified strong patterns of differentiation and reduced genetic diversity in high-latitude populations. In addition, genome-wide scans for selection identified a number of outlier loci putatively under directional selection with homology to proteins previously known to be involved in heat tolerance in corals and associated with processes such as photoprotection, protein degradation, and immunity. This study provides genomic evidence for both restricted gene flow and local adaptation in a widely distributed coral species, and highlights the potential vulnerability of leading-edge populations to rapid environmental change as they are locally adapted, reproductively isolated, and have reduced levels of genetic diversity. © 2017 John Wiley & Sons Ltd.

Fine-scale environmental specialization of reef-building corals might be limiting reef recovery in the Florida Keys.

PubMed

Kenkel, Carly D; Almanza, Albert T; Matz, Mikhail V

2015-12-01

Despite decades of monitoring global reef decline, we are still largely unable to explain patterns of reef deterioration at local scales, which precludes the development of effective management strategies. Offshore reefs of the Florida Keys, USA, experience milder temperatures and lower nutrient loads in comparison to inshore reefs yet remain considerably more degraded than nearshore patch reefs. A year-long reciprocal transplant experiment of the mustard hill coral (Porites astreoides) involving four source and eight transplant locations reveals that corals adapt and/or acclimatize to their local habitat on a < 10-km scale. Surprisingly, transplantation to putatively similar environmental types (e.g., offshore corals moved to a novel offshore site, or along-shore transplantation) resulted in greater reductions in fitness proxies, such as coral growth, than cross-channel transplantation between inshore and offshore reefs. The only abiotic factor showing significantly greater differences between along-shore sites was daily temperature range extremes (rather than the absolute high or low temperatures reached), providing a possible explanation for this pattern. Offshore-origin corals exhibited significant growth reductions at sites with greater daily temperature ranges, which explained up to 39% of the variation in their mass gain. In contrast, daily temperature range explained at most 9% of growth variation in inshore-origin corals, suggesting that inshore corals are more tolerant of high-frequency temperature fluctuations. Finally, corals incur trade-offs when specializing to their native reef. Across reef locations the coefficient of selection against coral transplants was 0.07 ± 0.02 (mean ± SE). This selection against immigrants could hinder the ability of corals to recolonize devastated reefs, whether through assisted migration efforts or natural recruitment events, providing a unifying explanation for observed patterns of coral decline in this reef system.

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

USGS Publications Warehouse

Rogers, C.S.; Miller, J.

2006-01-01

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

50 CFR 622.1 - Purpose and scope.

Code of Federal Regulations, 2014 CFR

2014-10-01

... for Coral, Coral Reefs, and Live/Hard Bottom Habitats of the South Atlantic Region SAFMC South Atlantic.5 FMP for Coral and Coral reefs of the Gulf of Mexico GMFMC Gulf. FMP for Corals and Reef... CFMC Caribbean. FMP for the Red Drum Fishery of the Gulf of Mexico GMFMC Gulf.1 FMP for the Reef Fish...

50 CFR 622.1 - Purpose and scope.

Code of Federal Regulations, 2013 CFR

2013-10-01

... for Coral, Coral Reefs, and Live/Hard Bottom Habitats of the South Atlantic Region SAFMC South Atlantic.5 FMP for Coral and Coral reefs of the Gulf of Mexico GMFMC Gulf. FMP for Corals and Reef... CFMC Caribbean. FMP for the Red Drum Fishery of the Gulf of Mexico GMFMC Gulf.1 FMP for the Reef Fish...

Geomorphological diversity of Dong-Sha Atoll based on spectrum and texture analysis in high resolution remote sensing imagery

NASA Astrophysics Data System (ADS)

Chen, Jianyu; Mao, Zhihua; He, Xianqiang

2009-01-01

Coral reefs are complex marine ecosystems that are constructed and maintained by biological communities that thrive in tropical oceans. The Dong-Sha Atoll is located at the northern continental margin of the South China Sea. It has being abused by destructive activity of human being and natural event during recent decades. Remote sensing offers a powerful tool for studying coral reef geomorphology and is the most cost-effective approach for large-scale reef survey. In this paper, the high-resolution Quickbird2 imageries which covered the full atoll are used to categorize the current distribution of coral reefs geomorphological structure therein with the auxiliary SPOT5 and ASTER imageries. Spectral and texture analysis are used to distinguish the geomorphological diversity during data processing. The Gray Level Co-occurrence Matrices is adopted for texture feature extraction and atoll geomorphology mapping in the high-resolution pan-color image of Quickbird2. Quickbird2 is considered as the most appropriate image source for coral reefs studies. In the Dong-Sha Atoll, various dynamical geomorphologic units are developed according to wave energy zones. There the reef frame types are classified to 3 different types according as its diversity at the image. The radial structure system is the most characteristic and from high resolution imagery we can distinguish the discrepancy between them.

Persistence and Change in Community Composition of Reef Corals through Present, Past, and Future Climates

PubMed Central

Edmunds, Peter J.; Adjeroud, Mehdi; Baskett, Marissa L.; Baums, Iliana B.; Budd, Ann F.; Carpenter, Robert C.; Fabina, Nicholas S.; Fan, Tung-Yung; Franklin, Erik C.; Gross, Kevin; Han, Xueying; Jacobson, Lianne; Klaus, James S.; McClanahan, Tim R.; O'Leary, Jennifer K.; van Oppen, Madeleine J. H.; Pochon, Xavier; Putnam, Hollie M.; Smith, Tyler B.; Stat, Michael; Sweatman, Hugh; van Woesik, Robert; Gates, Ruth D.

2014-01-01

The reduction in coral cover on many contemporary tropical reefs suggests a different set of coral community assemblages will dominate future reefs. To evaluate the capacity of reef corals to persist over various time scales, we examined coral community dynamics in contemporary, fossil, and simulated future coral reef ecosystems. Based on studies between 1987 and 2012 at two locations in the Caribbean, and between 1981 and 2013 at five locations in the Indo-Pacific, we show that many coral genera declined in abundance, some showed no change in abundance, and a few coral genera increased in abundance. Whether the abundance of a genus declined, increased, or was conserved, was independent of coral family. An analysis of fossil-reef communities in the Caribbean revealed changes in numerical dominance and relative abundances of coral genera, and demonstrated that neither dominance nor taxon was associated with persistence. As coral family was a poor predictor of performance on contemporary reefs, a trait-based, dynamic, multi-patch model was developed to explore the phenotypic basis of ecological performance in a warmer future. Sensitivity analyses revealed that upon exposure to thermal stress, thermal tolerance, growth rate, and longevity were the most important predictors of coral persistence. Together, our results underscore the high variation in the rates and direction of change in coral abundances on contemporary and fossil reefs. Given this variation, it remains possible that coral reefs will be populated by a subset of the present coral fauna in a future that is warmer than the recent past. PMID:25272143

77 FR 46682 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-06

...: National Oceanic and Atmospheric Administration (NOAA). Title: Pacific Islands Region Coral Reef Ecosystems.... Average Hours per Response: Coral Reef Ecosystem permits, 2 hours; appeals, 3 hours; transshipment permits..., taking, or retaining any Potentially Harvested Coral Reef Taxa (PHCRT) in the coral reef ecosystem...

78 FR 67128 - Coral Reef Conservation Program; Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-08

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Coral Reef Conservation Program; Meeting AGENCY: Coral Reef Conservation Program, Office of Ocean and Coastal Resource Management... meeting of the U.S. Coral Reef Task Force (USCRTF). The meeting will be held in Christiansted, U.S. Virgin...

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.

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.

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 Singapore’s reefs appears relatively constrained, which could lead to less resilient reefs. PMID:25992562

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's reefs appears relatively constrained, which could lead to less resilient reefs.

A modeling tool to evaluate regional coral reef responses to changes in climate and ocean chemistry

USGS Publications Warehouse

Buddemeier, R.W.; Jokiel, P.L.; Zimmerman, K.M.; Lane, D.R.; Carey, J.M.; Bohling, Geoffrey C.; Martinich, J.A.

2008-01-01

We developed a spreadsheet-based model for the use of managers, conservationists, and biologists for projecting the effects of climate change on coral reefs at local-to-regional scales. The COMBO (Coral Mortality and Bleaching Output) model calculates the impacts to coral reefs from changes in average SST and CO2 concentrations, and from high temperature mortality (bleaching) events. The model uses a probabilistic assessment of the frequency of high temperature events under a future climate to address scientific uncertainties about potential adverse effects. COMBO offers data libraries and default factors for three selected regions (Hawai'i, Great Barrier Reef, and Caribbean), but it is structured with user-selectable parameter values and data input options, making possible modifications to reflect local conditions or to incorporate local expertise. Preliminary results from sensitivity analyses and simulation examples for Hawai'i demonstrate the relative importance of high temperature events, increased average temperature, and increased CO2 concentration on the future status of coral reefs; Illustrate significant interactions among variables; and allow comparisons of past environmental history with future predictions. ?? 2008, by the American Society of Limnology and Oceanugraphy, Inc.

Simplification of Caribbean reef-fish assemblages over decades of coral reef degradation.

PubMed

Alvarez-Filip, Lorenzo; Paddack, Michelle J; Collen, Ben; Robertson, D Ross; Côté, Isabelle M

2015-01-01

Caribbean coral reefs are becoming structurally simpler, largely due to human impacts. The consequences of this trend for reef-associated communities are currently unclear, but expected to be profound. Here, we assess whether changes in fish assemblages have been non-random over several decades of declining reef structure. More specifically, we predicted that species that depend exclusively on coral reef habitat (i.e., habitat specialists) should be at a disadvantage compared to those that use a broader array of habitats (i.e., habitat generalists). Analysing 3727 abundance trends of 161 Caribbean reef-fishes, surveyed between 1980 and 2006, we found that the trends of habitat-generalists and habitat-specialists differed markedly. The abundance of specialists started to decline in the mid-1980s, reaching a low of ~60% of the 1980 baseline by the mid-1990s. Both the average and the variation in abundance of specialists have increased since the early 2000s, although the average is still well below the baseline level of 1980. This modest recovery occurred despite no clear evidence of a regional recovery in coral reef habitat quality in the Caribbean during the 2000s. In contrast, the abundance of generalist fishes remained relatively stable over the same three decades. Few specialist species are fished, thus their population declines are most likely linked to habitat degradation. These results mirror the observed trends of replacement of specialists by generalists, observed in terrestrial taxa across the globe. A significant challenge that arises from our findings is now to investigate if, and how, such community-level changes in fish populations affect ecosystem function.

Tropical cyclones cause CaCO3 undersaturation of coral reef seawater in a high-CO2 world

NASA Astrophysics Data System (ADS)

Manzello, Derek; Enochs, Ian; Musielewicz, Sylvia; Carlton, Renée.; Gledhill, Dwight

2013-10-01

Ocean acidification is the global decline in seawater pH and calcium carbonate (CaCO3) saturation state (Ω) due to the uptake of anthropogenic CO2 by the world's oceans. Acidification impairs CaCO3 shell and skeleton construction by marine organisms. Coral reefs are particularly vulnerable, as they are constructed by the CaCO3 skeletons of corals and other calcifiers. We understand relatively little about how coral reefs will respond to ocean acidification in combination with other disturbances, such as tropical cyclones. Seawater carbonate chemistry data collected from two reefs in the Florida Keys before, during, and after Tropical Storm Isaac provide the most thorough data to-date on how tropical cyclones affect the seawater CO2 system of coral reefs. Tropical Storm Isaac caused both an immediate and prolonged decline in seawater pH. Aragonite saturation state was depressed by 1.0 for a full week after the storm impact. Based on current "business-as-usual" CO2 emissions scenarios, we show that tropical cyclones with high rainfall and runoff can cause periods of undersaturation (Ω < 1.0) for high-Mg calcite and aragonite mineral phases at acidification levels before the end of this century. Week-long periods of undersaturation occur for 18 mol % high-Mg calcite after storms by the end of the century. In a high-CO2 world, CaCO3 undersaturation of coral reef seawater will occur as a result of even modest tropical cyclones. The expected increase in the strength, frequency, and rainfall of the most severe tropical cyclones with climate change in combination with ocean acidification will negatively impact the structural persistence of coral reefs.

Tropical Cyclones Cause CaCO3 Undersaturation of Coral Reef Seawater in a High-CO2 World

NASA Astrophysics Data System (ADS)

Manzello, D.; Enochs, I.; Carlton, R.; Musielewicz, S.; Gledhill, D. K.

2013-12-01

Ocean acidification is the global decline in seawater pH and calcium carbonate (CaCO3) saturation state (Ω) due to the uptake of anthropogenic CO2 by the world's oceans. Acidification impairs CaCO3 shell and skeleton construction by marine organisms. Coral reefs are particularly vulnerable, as they are constructed by the CaCO3 skeletons of corals and other calcifiers. We understand relatively little about how coral reefs will respond to ocean acidification in combination with other disturbances, such as tropical cyclones. Seawater carbonate chemistry data collected from two reefs in the Florida Keys before, during, and after Tropical Storm Isaac provide the most thorough data to-date on how tropical cyclones affect the seawater CO2-system of coral reefs. Tropical Storm Isaac caused both an immediate and prolonged decline in seawater pH. Aragonite saturation state was depressed by 1.0 for a full week after the storm impact. Based on current 'business-as-usual' CO2 emissions scenarios, we show that tropical cyclones with high rainfall and runoff can cause periods of undersaturation (Ω < 1.0) for high-Mg calcite and aragonite mineral phases at acidification levels before the end of this century. Week-long periods of undersaturation occur for 18 mol% high-Mg calcite after storms by the end of the century. In a high-CO2 world, CaCO3 undersaturation of coral reef seawater can occur as a result of even modest tropical cyclones. The expected increase in the strength, frequency, and rainfall of the most severe tropical cyclones with climate change in combination with ocean acidification will negatively impact the structural persistence of coral reefs over this century.

Observations of turbulent mixing in a shallow coral reef

NASA Astrophysics Data System (ADS)

Huang, Z. C.

2016-02-01

In situ measurements of waves, currents, and turbulence are presented to study turbulence properties within a depression that is surrounded by multiple coral-reef colonies in a fringing reef in Hobihu, Nan-Wan Bay, southern Taiwan. Turbulence was measured using a dual velocimetry technique, and wave bias contamination in the turbulence is controlled using ogive curve testing of the turbulent shear stress. The observed turbulent dissipation rate is approximately five times greater than simultaneous observations over the nearby sandy bottom site, which indicates stronger mixing within the coral reef than on sandy bottoms. Energetic downward momentum flux exists due to sweeping process; the turbulent kinetic energy is transported downward into the depression through the mechanisms of vertical turbulent transport and advection. The observed turbulent dissipation rate exceeds the shear production rate, which suggests that transport terms or other source terms might be important. The wake flow caused by the resistance force of coral colonies is examined. The form drag coefficient was estimated from the time-averaged alongshore linear momentum between two sites upstream and within the coral reef. The work done due to the form drag, which is termed the wake production, is found to strongly correlate and approximate well to the observed turbulent dissipation rate. The effects of waves and currents on the wake production are discussed. The observed TSS can be described well by classic turbulence closure model when the empirical stability function is adjusted. This study suggests that the complex canopy structure of multiple colonies and the coexistence of the wave-induced and current flows are significant factors for energetic turbulence in the coral reef, which could have positive effects to the health of the coral reefs.

Low coral cover in a high-CO2 world

NASA Astrophysics Data System (ADS)

Hoegh-Guldberg, Ove

2005-09-01

Coral reefs generally exist within a relatively narrow band of temperatures, light, and seawater aragonite saturation states. The growth of coral reefs is minimal or nonexistent outside this envelope. Climate change, through its effect on ocean temperature, has already had an impact on the world's coral reefs, with almost 30% of corals having disappeared since the beginning of the 1980s. Abnormally warm temperatures cause corals to bleach (lose their brown dinoflagellate symbionts) and, if elevated for long enough, to die. Increasing atmospheric CO2 is also potentially affecting coral reefs by lowering the aragonite saturation state of seawater, making carbonate ions less available for calcification. The synergistic interaction of elevated temperature and CO2 is likely to produce major changes to coral reefs over the next few decades and centuries. Known tolerances of corals to projected changes to sea temperatures indicate that corals are unlikely to remain abundant on reefs and could be rare by the middle of this century if the atmospheric CO2 concentration doubles or triples. The combination of changes to sea temperature and carbonate ion availability could trigger large-scale changes in the biodiversity and function of coral reefs. The ramifications of these changes for the hundred of millions of coral reef-dependent people and industries living in a high-CO2 world have yet to be properly defined. The weight of evidence suggests, however, that projected changes will cause major shifts in the prospects for industries and societies that depend on having healthy coral reefs along their coastlines.

In situ observations of coral bleaching in the central Saudi Arabian Red Sea during the 2015/2016 global coral bleaching event.

PubMed

Monroe, Alison A; Ziegler, Maren; Roik, Anna; Röthig, Till; Hardenstine, Royale S; Emms, Madeleine A; Jensen, Thor; Voolstra, Christian R; Berumen, Michael L

2018-01-01

Coral bleaching continues to be one of the most devastating and immediate impacts of climate change on coral reef ecosystems worldwide. In 2015, a major bleaching event was declared as the "3rd global coral bleaching event" by the United States National Oceanic and Atmospheric Administration, impacting a large number of reefs in every major ocean. The Red Sea was no exception, and we present herein in situ observations of the status of coral reefs in the central Saudi Arabian Red Sea from September 2015, following extended periods of high temperatures reaching upwards of 32.5°C in our study area. We examined eleven reefs using line-intercept transects at three different depths, including all reefs that were surveyed during a previous bleaching event in 2010. Bleaching was most prevalent on inshore reefs (55.6% ± 14.6% of live coral cover exhibited bleaching) and on shallower transects (41% ± 10.2% of live corals surveyed at 5m depth) within reefs. Similar taxonomic groups (e.g., Agariciidae) were affected in 2015 and in 2010. Most interestingly, Acropora and Porites had similar bleaching rates (~30% each) and similar relative coral cover (~7% each) across all reefs in 2015. Coral genera with the highest levels of bleaching (>60%) were also among the rarest (<1% of coral cover) in 2015. While this bodes well for the relative retention of coral cover, it may ultimately lead to decreased species richness, often considered an important component of a healthy coral reef. The resultant long-term changes in these coral reef communities remain to be seen.

In situ observations of coral bleaching in the central Saudi Arabian Red Sea during the 2015/2016 global coral bleaching event

PubMed Central

Ziegler, Maren; Roik, Anna; Röthig, Till; Hardenstine, Royale S.; Emms, Madeleine A.; Jensen, Thor; Voolstra, Christian R.; Berumen, Michael L.

2018-01-01

Coral bleaching continues to be one of the most devastating and immediate impacts of climate change on coral reef ecosystems worldwide. In 2015, a major bleaching event was declared as the “3rd global coral bleaching event” by the United States National Oceanic and Atmospheric Administration, impacting a large number of reefs in every major ocean. The Red Sea was no exception, and we present herein in situ observations of the status of coral reefs in the central Saudi Arabian Red Sea from September 2015, following extended periods of high temperatures reaching upwards of 32.5°C in our study area. We examined eleven reefs using line-intercept transects at three different depths, including all reefs that were surveyed during a previous bleaching event in 2010. Bleaching was most prevalent on inshore reefs (55.6% ± 14.6% of live coral cover exhibited bleaching) and on shallower transects (41% ± 10.2% of live corals surveyed at 5m depth) within reefs. Similar taxonomic groups (e.g., Agariciidae) were affected in 2015 and in 2010. Most interestingly, Acropora and Porites had similar bleaching rates (~30% each) and similar relative coral cover (~7% each) across all reefs in 2015. Coral genera with the highest levels of bleaching (>60%) were also among the rarest (<1% of coral cover) in 2015. While this bodes well for the relative retention of coral cover, it may ultimately lead to decreased species richness, often considered an important component of a healthy coral reef. The resultant long-term changes in these coral reef communities remain to be seen. PMID:29672556

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

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-26

... DEPARTMENT OF THE INTERIOR National Park Service Coral Reef Restoration Plan, Draft Programmatic... Coral Reef Restoration Plan, Biscayne National Park. SUMMARY: Pursuant to the National Environmental... availability of a Draft Programmatic Environmental Impact Statement (DEIS) for the Coral Reef Restoration Plan...

Experimental Bleaching of a Reef-Building Coral Using a Simplified Recirculating Laboratory Exposure System

EPA Science Inventory

Determining stressor-response relationships in reef building corals is a critical need for researchers because of global declines in coral reef ecosystems. A simplified recirculating coral exposure system for laboratory testing of a diversity of species and morphologies of reef b...

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.

Coral reefs in an urban embayment in Hawaii: a complex case history controlled by natural and anthropogenic stress

NASA Astrophysics Data System (ADS)

Grigg, R. W.

1995-11-01

The effects of natural and anthropogenic stress need to be separated before coral reef ecosystems can be effectively managed. In this paper, a 25 year case history of coral reefs in an urban embayment (Mamala Bay) off Honolulu, Hawaii is described and differences between natural and man-induced stress are distinguished. Mamala Bay is a 30 km long shallow coastal bay bordering the southern (leeward) shore of Oahu and the city of Honolulu in the Hawaiian Islands. During the last 25 years, this area has been hit by two magnitude 5 hurricane events (winds > 240 km/h) generating waves in excess of 7.5 m. Also during this period, two large sewer outfalls have discharged up to 90 million gallons per day (mgd) or (360 × 106 L/day) of point source pollution into the bay. Initially the discharge was raw sewage, but since 1977 it has received advanced primary treatment. Non-point source run-off from the Honolulu watershed also enters the bay on a daily basis. The results of the study show that discharge of raw sewage had a serious but highly localized impact on shallow (˜10 m) reef corals in the bay prior to 1977. After 1977, when treatment was upgraded to the advanced primary level and outfalls were extended to deep water (> 65 m), impacts to reef corals were no longer significant. No measurable effects of either point or non-point source pollution on coral calcification, growth, species composition, diversity or community structure related to pollution can now be detected. Conversely the effects of hurricane waves in 1982 and 1992 together caused major physical destruction to the reefs. In 1982, average coral cover of well-developed offshore reefs dropped from 60-75% to 5-15%. Only massive species in high relief areas survived. Today, recovery is occurring, and notwithstanding major future disturbance events, long-term biological processes should eventually return the coral ecosystems to a more mature successional stage. This case history illustrates the complex nature of the cumulative effects of natural and anthropogenic stress on coral reefs and the need for a long-term data base before the status of a coral reef can be properly interpreted.

Satellite Remote Sensing of Coral Reefs: By Learning about Coral Reefs, Students Gain an Understanding of Ecosystems and How Cutting-Edge Technology Can Be Used to Study Ecological Change

ERIC Educational Resources Information Center

Palandro, David; Thoms, Kristin; Kusek, Kristen; Muller-Karger, Frank; Greely, Teresa

2005-01-01

Coral reefs are one of the most important ecosystems on the planet, providing sustenance to both marine organisms and humans. Yet they are also one of the most endangered ecosystems as coral reef coverage has declined dramatically in the past three decades. Researchers continually seek better ways to map coral reef coverage and monitor changes…

77 FR 66 - Western Pacific Fisheries; 2012 Annual Catch Limits and Accountability Measures

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-03

... proposes annual catch limits for western Pacific bottomfish, crustacean, precious coral, and coral reef... specify ACLs for bottomfish, crustacean, precious coral, and coral reef ecosystem fishery MUS in American... bottomfish, crustacean, precious coral, or coral reef ecosystem MUS in the PRIA because commercial fishing is...

78 FR 6798 - Western Pacific Fisheries; 2013 Annual Catch Limits and Accountability Measures

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-31

... proposes annual catch limits for western Pacific bottomfish, crustacean, precious coral, and coral reef... ACLs for bottomfish, crustacean, precious coral, and coral reef ecosystem fishery MUS in American Samoa... to 2012. NMFS is not proposing ACLs for bottomfish, crustacean, precious coral, or coral reef...

Influence of landscape structure on reef fish assemblages

USGS Publications Warehouse

Grober-Dunsmore, R.; Frazer, T.K.; Beets, J.P.; Lindberg, W.J.; Zwick, P.; Funicelli, N.A.

2008-01-01

Management of tropical marine environments calls for interdisciplinary studies and innovative methodologies that consider processes occurring over broad spatial scales. We investigated relationships between landscape structure and reef fish assemblage structure in the US Virgin Islands. Measures of landscape structure were transformed into a reduced set of composite indices using principal component analyses (PCA) to synthesize data on the spatial patterning of the landscape structure of the study reefs. However, composite indices (e.g., habitat diversity) were not particularly informative for predicting reef fish assemblage structure. Rather, relationships were interpreted more easily when functional groups of fishes were related to individual habitat features. In particular, multiple reef fish parameters were strongly associated with reef context. Fishes responded to benthic habitat structure at multiple spatial scales, with various groups of fishes each correlated to a unique suite of variables. Accordingly, future experiments should be designed to test functional relationships based on the ecology of the organisms of interest. Our study demonstrates that landscape-scale habitat features influence reef fish communities, illustrating promise in applying a landscape ecology approach to better understand factors that structure coral reef ecosystems. Furthermore, our findings may prove useful in design of spatially-based conservation approaches such as marine protected areas (MPAs), because landscape-scale metrics may serve as proxies for areas with high species diversity and abundance within the coral reef landscape. ?? 2007 Springer Science+Business Media B.V.

Chemically rich seaweeds poison corals when not controlled by herbivores

PubMed Central

Rasher, Douglas B.; Hay, Mark E.

2010-01-01

Coral reefs are in dramatic global decline, with seaweeds commonly replacing corals. It is unclear, however, whether seaweeds harm corals directly or colonize opportunistically following their decline and then suppress coral recruitment. In the Caribbean and tropical Pacific, we show that, when protected from herbivores, ~40 to 70% of common seaweeds cause bleaching and death of coral tissue when in direct contact. For seaweeds that harmed coral tissues, their lipid-soluble extracts also produced rapid bleaching. Coral bleaching and mortality was limited to areas of direct contact with seaweeds or their extracts. These patterns suggest that allelopathic seaweed-coral interactions can be important on reefs lacking herbivore control of seaweeds, and that these interactions involve lipid-soluble metabolites transferred via direct contact. Seaweeds were rapidly consumed when placed on a Pacific reef protected from fishing but were left intact or consumed at slower rates on an adjacent fished reef, indicating that herbivory will suppress seaweeds and lower frequency of allelopathic damage to corals if reefs retain intact food webs. With continued removal of herbivores from coral reefs, seaweeds are becoming more common. This occurrence will lead to increasing frequency of seaweed-coral contacts, increasing allelopathic suppression of remaining corals, and continuing decline of reef corals. PMID:20457927

Chemically rich seaweeds poison corals when not controlled by herbivores.

PubMed

Rasher, Douglas B; Hay, Mark E

2010-05-25

Coral reefs are in dramatic global decline, with seaweeds commonly replacing corals. It is unclear, however, whether seaweeds harm corals directly or colonize opportunistically following their decline and then suppress coral recruitment. In the Caribbean and tropical Pacific, we show that, when protected from herbivores, approximately 40 to 70% of common seaweeds cause bleaching and death of coral tissue when in direct contact. For seaweeds that harmed coral tissues, their lipid-soluble extracts also produced rapid bleaching. Coral bleaching and mortality was limited to areas of direct contact with seaweeds or their extracts. These patterns suggest that allelopathic seaweed-coral interactions can be important on reefs lacking herbivore control of seaweeds, and that these interactions involve lipid-soluble metabolites transferred via direct contact. Seaweeds were rapidly consumed when placed on a Pacific reef protected from fishing but were left intact or consumed at slower rates on an adjacent fished reef, indicating that herbivory will suppress seaweeds and lower frequency of allelopathic damage to corals if reefs retain intact food webs. With continued removal of herbivores from coral reefs, seaweeds are becoming more common. This occurrence will lead to increasing frequency of seaweed-coral contacts, increasing allelopathic suppression of remaining corals, and continuing decline of reef corals.

Catastrophic impact of typhoon waves on coral communities in the Ryukyu Islands under global warming

NASA Astrophysics Data System (ADS)

Hongo, Chuki; Kawamata, Hideki; Goto, Kazuhisa

2012-06-01

Typhoon-generated storm waves generally cause mechanical damage to coral communities on present-day reefs, and the magnitude and extent of damage is predicted to increase in the near future as a result of global warming. Therefore, a comprehensive understanding of potential future scenarios of reef ecosystems is of prime interest. This study assesses the current status of coral communities on Ibaruma reef, Ryukyu Islands, on the basis of field observations, engineering and fluid dynamic models, and calculations of wave motion, and predicts the potential effects of a super-extreme typhoon (incident wave height,H = 20 m; wave period, T = 20 s) on the reef. On the present-day reef, massive corals occur in shallow lagoons and tabular corals occur from the reef crest to the reef slope. The observed distribution of corals, which is frequently attacked by moderate (H = 10 m, T = 10 s) and extreme (H = 10 m, T = 15 s) typhoons, is consistent with the predictions of engineering models. Moreover, this study indicates that if a super-extreme typhoon attacks the reef in the near future, massive corals will survive in the shallow lagoons but tabular corals on the reef crest and reef slope will be severely impacted. The findings imply that super-extreme typhoons will cause a loss of species diversity, as the tabular corals are important reef builders and are critical to the maintenance of reef ecosystems. Consequently, reef restoration is a key approach to maintaining reef ecosystems in the wake of super-extreme typhoons.

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

PubMed

Burt, John A

2013-07-30

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

Genome-Based Analyses of Six Hexacorallian Species Reject the "Naked Coral" Hypothesis.

PubMed

Wang, Xin; Drillon, Guénola; Ryu, Taewoo; Voolstra, Christian R; Aranda, Manuel

2017-10-01

Scleractinian corals are the foundation species of the coral-reef ecosystem. Their calcium carbonate skeletons form extensive structures that are home to millions of species, making coral reefs one of the most diverse ecosystems of our planet. However, our understanding of how reef-building corals have evolved the ability to calcify and become the ecosystem builders they are today is hampered by uncertain relationships within their subclass Hexacorallia. Corallimorpharians have been proposed to originate from a complex scleractinian ancestor that lost the ability to calcify in response to increasing ocean acidification, suggesting the possibility for corals to lose and gain the ability to calcify in response to increasing ocean acidification. Here, we employed a phylogenomic approach using whole-genome data from six hexacorallian species to resolve the evolutionary relationship between reef-building corals and their noncalcifying relatives. Phylogenetic analysis based on 1,421 single-copy orthologs, as well as gene presence/absence and synteny information, converged on the same topologies, showing strong support for scleractinian monophyly and a corallimorpharian sister clade. Our broad phylogenomic approach using sequence-based and sequence-independent analyses provides unambiguous evidence for the monophyly of scleractinian corals and the rejection of corallimorpharians as descendants of a complex coral ancestor. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Conservation status and spatial patterns of AGRRA vitality indices in Southwestern Atlantic reefs.

PubMed

Kikuchi, Ruy K P; Leão, Zelinda M A N; Oliveira, Marília D M

2010-05-01

Coral reefs along the Eastern Brazilian coast extend for a distance of 800 km from 12 degrees to 18 degrees S. They are the largest and the richest reefs of Brazil coasts, and represent the Southernmost coral reefs of the Southwestern Atlantic Ocean. Few reef surveys were performed in the 90's in reef areas of Bahia State, particularly in the Abrolhos reef complex, in the Southernmost side of the state. A monitoring program applying the Atlantic and Gulf Rapid Reef Assessment (AGRRA) protocol was initiated in 2000, in the Abrolhos National Marine Park, after the creation of the South Tropical America (STA) Regional Node of the Global Coral Reef Monitoring Network (GCRMN) by the end of 1999. From that time up to 2005, nine reef surveys were conducted along the coast of the State of Bahia, including 26 reefs, with 95 benthic sites, 280 benthic transects, 2025 quadrats and 3537 stony corals. Eighteen of the 26 investigated reefs were assessed once and eight reefs of Abrolhos were surveyed twice to four times. The MDS ordination, analysis of similarity (ANOSIM, one way and two-way nested layouts) and similarity percentages (SIMPER) tests were applied to investigate the spatial and temporal patterns of reef vitality. Four indicators of the coral vitality: live coral cover, the density of the larger corals (colonics > 20cm per reef site) and of the coral recruits (colonies < 2cm per square meter), and the percentage of macroalgae indicate that the nearshore reefs, which are located less than 5 km from the coast, are in poorer condition than the reefs located more than 5 km off the coast. A higher density of coral colonies, lower macroalgal index, higher relative percent of turf algae and higher density of coral recruits in offshore reefs compared to the nearshore reefs are the conditions that contribute more than 80% to the dissimilarity between them. The offshore reefs are in better vital condition than the nearshore reefs and have a set of vitality indices more closely related to the Northwestern Atlantic reefs than the nearshore reef. These have been most severely impacted by the effects of direct human activities such as cuthrophic waters associated with sewage pollution, higher sedimentation rates and water turbidity, inadequate use of the reefs and over exploitation of their resources. The implementation of a more effective coral reef monitoring program in Bahia is mandatory, in order to improve the strategies for protection and management efforts of the reefs.

Where's the reef: the role of framework in the Holocene

USGS Publications Warehouse

Hubbard, D.K.; Burke, R.B.; Gill, I.P.

1998-01-01

Holocene reef models generally emphasize the role of in-place and interlocking framework in the creation of a rigid structure that rises above its surroundings. By extension, a number of ancient biohermal deposits have been disqualified as 'true reefs' owing to their lack of recognizable framework. Fifty-four cores from several eastern Caribbean sites clearly demonstrate that in-place and interlocking framework is not common in these reefs that are comprised of varying mixtures of recognizable coral (primary framework), loose sediment/rubble and secondary framework made up mostly of coralgal fragments bound together by submarine cementation and biological encrustation. Recvovery of primary and secondary framework ranged from 22% (avg.) in branching-coral facies to 33% in intervals dominated by head corals. Accretion rate decreases as expected with water depth. However, the recovery of recognizable coral generally increased with water depth, inversely to presumed coral-growth rates. This pattern reflects a spectrum in the relative importance of coral growth (primary construction), bioerosion, hydromechanical breakdown and the transport of sediment and detritus. The relative importance of each is controlled by the physical-oceanographic conditions at the stie of reef development and will dictate both the architecture and the character of its internal fabric. We do not propose that framework reeds do not exist, as they most assuredly do. However, the fact that so many modern reefs are not dominated by in-place and interlocking framework suggests that its use as the primary determinant of ancient reefs may be unreasonable. We, therefore, propose the abandonment of framework-based models in favor of those that treat framework generation, physical/biological degradation, sedimentation, and encrustation as equal partners in the development of modern and ancient reefs alike.

Improved water quality can ameliorate effects of climate change on corals.

PubMed

Wooldridge, Scott A; Done, Terence J

2009-09-01

The threats of wide-scale coral bleaching and reef demise associated with anthropogenic climate change are widely known. Moreover, rates of genetic adaptation and/or changes in the coral-zooxanthella partnerships are considered unlikely to be sufficiently fast for corals to acquire increased physiological resistance to increasing sea temperatures and declining pH. However, it has been suggested that coral reef resilience to climate change may be improved by good local management of coral reefs, including management of water quality. Here, using major data sets from the Great Barrier Reef (GBR), Australia, we investigate geographic patterns of coral bleaching in 1998 and 2002 and outline a synergism between heat stress and nutrient flux as a major causative mechanism for those patterns. The study provides the first concrete evidence for the oft-expressed belief that improved coral reef management will increase the regional-scale survival prospects of coral reefs to global climate change.

Neogene reef coral assemblages of the Bocas del Toro region, Panama: the rise of Acropora palmata

NASA Astrophysics Data System (ADS)

Klaus, J. S.; McNeill, D. F.; Budd, A. F.; Coates, A. G.

2012-03-01

Temporal patterns are evaluated in Neogene reef coral assemblages from the Bocas del Toro Basin of Panama in order to understand how reef ecosystems respond to long-term environmental change. Analyses are based on a total of 1,702 zooxanthellate coral specimens collected from six coral-bearing units ranging in age from the earliest Late Miocene to the Early Pleistocene: (1) Valiente Formation (12-11 Ma), (2) Fish Hole Member of the Old Bank Formation (5.8-5.6 Ma), (3) La Gruta Member of the Isla Colon Formation (2.2-1.4 Ma), (4) Ground Creek Member of the Isla Colon Formation (2.2-1.4 Ma), (5) Mimitimbi Member of the Urracá Formation (1.2-0.8 Ma), and (6) Hill Point Member of the Urracá Formation (1.2-0.8 Ma). Over 100 coral species occur in the six units, with faunal assemblages ranging from less than 10% extant taxa (Valiente Formation) to over 85% extant taxa (Ground Creek Member). The collections provide new temporal constraints on the emergence of modern Caribbean reefs, with the La Gruta Member containing the earliest occurrence of large monospecific stands of the dominant Caribbean reef coral Acropora palmata, and the Urracá Formation containing the last fossil occurrences of 15 regionally extinct taxa. Canonical correspondence analysis of 41 Late Miocene to Recent reef coral assemblages from the Caribbean region suggests changes in community structure coincident with effective oceanic closure of the Central American Seaway (~3.5 Ma). These changes, including increased Acropora dominance, may have contributed to a protracted period of elevated extinction debt prior to the major peak in regional coral extinctions (~2-1 Ma).

Assessing the spatial distribution of coral bleaching using small unmanned aerial systems

NASA Astrophysics Data System (ADS)

Levy, Joshua; Hunter, Cynthia; Lukacazyk, Trent; Franklin, Erik C.

2018-06-01

Small unmanned aerial systems (sUAS) are an affordable, effective complement to existing coral reef monitoring and assessment tools. sUAS provide repeatable low-altitude, high-resolution photogrammetry to address fundamental questions of spatial ecology and community dynamics for shallow coral reef ecosystems. Here, we qualitatively describe the use of sUAS to survey the spatial characteristics of coral cover and the distribution of coral bleaching across patch reefs in Kānéohe Bay, Hawaii, and address limitations and anticipated technology advancements within the field of UAS. Overlapping sub-decimeter low-altitude aerial reef imagery collected during the 2015 coral bleaching event was used to construct high-resolution reef image mosaics of coral bleaching responses on four Kānéohe Bay patch reefs, totaling 60,000 m2. Using sUAS imagery, we determined that paled, bleached and healthy corals on all four reefs were spatially clustered. Comparative analyses of data from sUAS imagery and in situ diver surveys found as much as 14% difference in coral cover values between survey methods, depending on the size of the reef and area surveyed. When comparing the abundance of unhealthy coral (paled and bleached) between sUAS and in situ diver surveys, we found differences in cover from 1 to 49%, depending on the depth of in situ surveys, the percent of reef area covered with sUAS surveys and patchiness of the bleaching response. This study demonstrates the effective use of sUAS surveys for assessing the spatial dynamics of coral bleaching at colony-scale resolutions across entire patch reefs and evaluates the complementarity of data from both sUAS and in situ diver surveys to more accurately characterize the spatial ecology of coral communities on reef flats and slopes.

50 CFR 665.421 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Definitions. As used in §§ 665.420 through 665.439: Mariana coral reef ecosystem management unit species (Mariana coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.621 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... § 665.621 Definitions. As used in §§ 665.620 through 665.639: PRIA coral reef ecosystem management unit species (PRIA coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic...

50 CFR 665.221 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

.... As used in §§ 665.220 through 665.239: Hawaii coral reef ecosystem management unit species (Hawaii coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.621 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... § 665.621 Definitions. As used in §§ 665.620 through 665.639: PRIA coral reef ecosystem management unit species (PRIA coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic...

50 CFR 665.221 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

.... As used in §§ 665.220 through 665.239: Hawaii coral reef ecosystem management unit species (Hawaii coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.221 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

.... As used in §§ 665.220 through 665.239: Hawaii coral reef ecosystem management unit species (Hawaii coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.421 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Definitions. As used in §§ 665.420 through 665.439: Mariana coral reef ecosystem management unit species (Mariana coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.621 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... § 665.621 Definitions. As used in §§ 665.620 through 665.639: PRIA coral reef ecosystem management unit species (PRIA coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic...

50 CFR 665.421 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Definitions. As used in §§ 665.420 through 665.439: Mariana coral reef ecosystem management unit species (Mariana coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

Assessing the sensitivity of coral reef condition indicators to local and global stressors with Bayesian networks

EPA Science Inventory

Coral reefs are highly valued ecosystems that are currently imperiled. Although the value of coral reefs to human societies is only just being investigated and better understood, for many local and global economies coral reefs are important providers of ecosystem services that su...

77 FR 12243 - Proposed Information Collection; Comment Request; Pacific Islands Region Coral Reef Ecosystems...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-29

... Collection; Comment Request; Pacific Islands Region Coral Reef Ecosystems Permit Form AGENCY: National... using a vessel to fish for Western Pacific coral reef ecosystem management unit species in the... allowed in the regulations; or (3) fishing for, taking, or retaining any Potentially Harvested Coral Reef...

50 CFR 665.121 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Definitions. As used in §§ 665.120 through 665.139: American Samoa coral reef ecosystem management unit species (American Samoa coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic...

50 CFR 665.421 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Definitions. As used in §§ 665.420 through 665.439: Mariana coral reef ecosystem management unit species (Mariana coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.221 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

.... As used in §§ 665.220 through 665.239: Hawaii coral reef ecosystem management unit species (Hawaii coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.121 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Definitions. As used in §§ 665.120 through 665.139: American Samoa coral reef ecosystem management unit species (American Samoa coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic...

50 CFR 665.421 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Definitions. As used in §§ 665.420 through 665.439: Mariana coral reef ecosystem management unit species (Mariana coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.621 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... § 665.621 Definitions. As used in §§ 665.620 through 665.639: PRIA coral reef ecosystem management unit species (PRIA coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic...

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

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-01

... Collection; Comment Request; Pacific Islands Region Coral Reef Ecosystems Logbook and Reporting AGENCY... with, or any U.S. citizen issued with, a Special Coral Reef Ecosystem Fishing Permit (authorized under the Fishery Management Plan for Coral Reef Ecosystems of the Western Pacific Region), to complete...

78 FR 49258 - Fisheries in the Western Pacific; Special Coral Reef Ecosystem Fishing Permit

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-13

... the Western Pacific; Special Coral Reef Ecosystem Fishing Permit AGENCY: National Marine Fisheries... Reef Ecosystem Fishing Permit that would authorize Kampachi Farms, LLC, to culture and harvest a coral...: NMFS proposes to issue a Special Coral Reef Ecosystem Fishing Permit to Kampachi Farms, LLC, consistent...

76 FR 24050 - Coral Reef Restoration Plan, Final Programmatic Environmental Impact Statement, Biscayne National...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-29

... DEPARTMENT OF THE INTERIOR National Park Service [2310-0003-422] Coral Reef Restoration Plan... for the Coral Reef Restoration Plan, Biscayne National Park. SUMMARY: Pursuant to the National... availability of a Final Programmatic Environmental Impact Statement for the Coral Reef Restoration Plan (Plan...

50 CFR 665.221 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

.... As used in §§ 665.220 through 665.239: Hawaii coral reef ecosystem management unit species (Hawaii coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic (post...

50 CFR 665.621 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... § 665.621 Definitions. As used in §§ 665.620 through 665.639: PRIA coral reef ecosystem management unit species (PRIA coral reef ecosystem MUS) means all of the Currently Harvested Coral Reef Taxa and Potentially Harvested Coral Reef Taxa listed in this section and which spend the majority of their non-pelagic...

Webinar on PTM with CMS

DTIC Science & Technology

2013-12-04

Coral Reef Dredging Project SAV Migrating Fish Coral Reef Dredging Project SAV Migrating Fish... Coral Reef Dredging Project SAV Migrating Fish Coral Reef Dredging Project Coastal and Hydraulics Laboratory 22 Dredging Materials and...Introduction to CMS Coastal and Hydraulics Laboratory Integrated waves , current, and sediment transport model in the Surface-water Modeling

Developing the Biological Condition Gradient (BCG), as a Tool for Describing the Condition of US Coral Reefs

EPA Science Inventory

Understanding effects of human activity on coral reefs requires knowing what characteristics constitute a high quality coral reef and identifying measurable criteria. The BCG is a conceptual model that describes how biological attributes of coral reefs change along a gradient of ...

Taphonomy of coral reefs from Southern Lagoon of Belize

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westphall, M.J.; Ginsburg, R.N.

1985-02-01

The Southern Lagoon of the Belize barrier complex, an area of some 600 km/sup 2/, contains a tremendous number of lagoon reefs, which range in size from patches several meters across to rhomboidal-shaped structures several kilometers in their long dimension. These lagoon reefs are remarkable because they have Holocene sediment accumulations in excess of 13 m consisting almost entirely of coral debris and lime mud and sand, and rise up to 30 m above the surrounding lagoon floor with steeply sloping sides (50-80/sup 0/), yet are totally uncemented. The reef-building biota and their corresponding deposits were studied at a representativemore » reef, the rhomboidal complex of Channel Cay. As with many of the reefs in this area, the steeply sloping flanks of Channel Cay are covered mainly by the branched staghorn coral Acropora cervicornis and ribbonlike and platy growth of Agaricia spp. The living corals are not cemented to the substrate, but are merely intergrown. Fragmented pieces of corals accumulate with an open framework below the living community; this open framework is subsequently infilled by lime muds and sands produced mainly from bioerosion. Results from probing and coring suggest that the bafflestone fabric of coral debris and sediment extends at least 13 m into the subsurface. Radiocarbon-age estimates indicate these impressive piles of coral rubble and sediment have accumulated in the past 9000 yr (giving a minimum accumulation rate of 1.4 m/1000 yr) and illustrate the potential for significant carbonate buildups without the need for early lithification.« less

Atoll-scale patterns in coral reef community structure: Human signatures on Ulithi Atoll, Micronesia

PubMed Central

Nelson, Peter; Abelson, Avigdor; Precoda, Kristin; Rulmal, John; Bernardi, Giacomo; Paddack, Michelle

2017-01-01

The dynamic relationship between reefs and the people who utilize them at a subsistence level is poorly understood. This paper characterizes atoll-scale patterns in shallow coral reef habitat and fish community structure, and correlates these with environmental characteristics and anthropogenic factors, critical to conservation efforts for the reefs and the people who depend on them. Hierarchical clustering analyses by site for benthic composition and fish community resulted in the same 3 major clusters: cluster 1–oceanic (close proximity to deep water) and uninhabited (low human impact); cluster 2–oceanic and inhabited (high human impact); and cluster 3–lagoonal (facing the inside of the lagoon) and inhabited (highest human impact). Distance from village, reef exposure to deep water and human population size had the greatest effect in predicting the fish and benthic community structure. Our study demonstrates a strong association between benthic and fish community structure and human use across the Ulithi Atoll (Yap State, Federated States of Micronesia) and confirms a pattern observed by local people that an ‘opportunistic’ scleractinian coral (Montipora sp.) is associated with more highly impacted reefs. Our findings suggest that small human populations (subsistence fishing) can nevertheless have considerable ecological impacts on reefs due, in part, to changes in fishing practices rather than overfishing per se, as well as larger global trends. Findings from this work can assist in building local capacity to manage reef resources across an atoll-wide scale, and illustrates the importance of anthropogenic impact even in small communities. PMID:28489903

Status and progress in coral reef disease research.

PubMed

Weil, Ernesto; Smith, Garriet; Gil-Agudelo, Diego L

2006-03-23

Recent findings on the ecology, etiology and pathology of coral pathogens, host resistance mechanisms, previously unknown disease/syndromes and the global nature of coral reef diseases have increased our concern about the health and future of coral reef communities. Much of what has been discovered in the past 4 years is presented in this special issue. Among the significant findings, the role that various Vibrio species play in coral disease and health, the composition of the 'normal microbiota' of corals, and the possible role of viruses in the disease process are important additions to our knowledge. New information concerning disease resistance and vectors, variation in pathogen composition for both fungal diseases of gorgonians and black band disease across oceans, environmental effects on disease susceptibility and resistance, and temporal and spatial disease variations among different coral species is presented in a number of papers. While the Caribbean may still be the 'disease hot spot' for coral reefs, it is now clear that diseases of coral reef organisms have become a global threat to coral reefs and a major cause of reef deterioration.

The dynamics of architectural complexity on coral reefs under climate change.

PubMed

Bozec, Yves-Marie; Alvarez-Filip, Lorenzo; Mumby, Peter J

2015-01-01

One striking feature of coral reef ecosystems is the complex benthic architecture which supports diverse and abundant fauna, particularly of reef fish. Reef-building corals are in decline worldwide, with a corresponding loss of live coral cover resulting in a loss of architectural complexity. Understanding the dynamics of the reef architecture is therefore important to envision the ability of corals to maintain functional habitats in an era of climate change. Here, we develop a mechanistic model of reef topographical complexity for contemporary Caribbean reefs. The model describes the dynamics of corals and other benthic taxa under climate-driven disturbances (hurricanes and coral bleaching). Corals have a simplified shape with explicit diameter and height, allowing species-specific calculation of their colony surface and volume. Growth and the mechanical (hurricanes) and biological erosion (parrotfish) of carbonate skeletons are important in driving the pace of extension/reduction in the upper reef surface, the net outcome being quantified by a simple surface roughness index (reef rugosity). The model accurately simulated the decadal changes of coral cover observed in Cozumel (Mexico) between 1984 and 2008, and provided a realistic hindcast of coral colony-scale (1-10 m) changing rugosity over the same period. We then projected future changes of Caribbean reef rugosity in response to global warming. Under severe and frequent thermal stress, the model predicted a dramatic loss of rugosity over the next two or three decades. Critically, reefs with managed parrotfish populations were able to delay the general loss of architectural complexity, as the benefits of grazing in maintaining living coral outweighed the bioerosion of dead coral skeletons. Overall, this model provides the first explicit projections of reef rugosity in a warming climate, and highlights the need of combining local (protecting and restoring high grazing) to global (mitigation of greenhouse gas emissions) interventions for the persistence of functional reef habitats. © 2014 John Wiley & Sons Ltd.

Population Genetics of an Ecosystem-Defining Reef Coral Pocillopora damicornis in the Tropical Eastern Pacific

PubMed Central

Combosch, David J.; Vollmer, Steven V.

2011-01-01

Background Coral reefs in the Tropical Eastern Pacific (TEP) are amongst the most peripheral and geographically isolated in the world. This isolation has shaped the biology of TEP organisms and lead to the formation of numerous endemic species. For example, the coral Pocillopora damicornis is a minor reef-builder elsewhere in the Indo-West Pacific, but is the dominant reef-building coral in the TEP, where it forms large, mono-specific stands, covering many hectares of reef. Moreover, TEP P. damicornis reproduces by broadcast spawning, while it broods mostly parthenogenetic larvae throughout the rest of the Indo-West Pacific. Population genetic surveys for P. damicornis from across its Indo-Pacific range indicate that gene flow (i.e. larval dispersal) is generally limited over hundreds of kilometers or less. Little is known about the population genetic structure and the dispersal potential of P. damicornis in the TEP. Methodology Using multilocus microsatellite data, we analyzed the population structure of TEP P. damicornis among and within nine reefs and test for significant genetic structure across three geographically and ecologically distinct regions in Panama. Principal Findings/Conclusions We detected significant levels of population genetic structure (global RST = 0.162), indicating restricted gene flow (i.e. larvae dispersal), both among the three regions (RRT = 0.081) as well as within regions (RSR = 0.089). Limited gene flow across a distinct environmental cline, like the regional upwelling gradient in Panama, indicates a significant potential for differential adaptation and population differentiation. Individual reefs were characterized by unexpectedly high genet diversity (avg. 94%), relatively high inbreeding coefficients (global FIS = 0.183), and localized spatial genetic structure among individuals (i.e. unique genets) over 10 m intervals. These findings suggest that gene flow is limited in TEP P. damicornis populations, particularly among regions, but even over meter scales within populations. PMID:21857900

A linked land-sea modeling framework to inform ridge-to-reef management in high oceanic islands.

PubMed

Delevaux, Jade M S; Whittier, Robert; Stamoulis, Kostantinos A; Bremer, Leah L; Jupiter, Stacy; Friedlander, Alan M; Poti, Matthew; Guannel, Greg; Kurashima, Natalie; Winter, Kawika B; Toonen, Robert; Conklin, Eric; Wiggins, Chad; Knudby, Anders; Goodell, Whitney; Burnett, Kimberly; Yee, Susan; Htun, Hla; Oleson, Kirsten L L; Wiegner, Tracy; Ticktin, Tamara

2018-01-01

Declining natural resources have led to a cultural renaissance across the Pacific that seeks to revive customary ridge-to-reef management approaches to protect freshwater and restore abundant coral reef fisheries. Effective ridge-to-reef management requires improved understanding of land-sea linkages and decision-support tools to simultaneously evaluate the effects of terrestrial and marine drivers on coral reefs, mediated by anthropogenic activities. Although a few applications have linked the effects of land cover to coral reefs, these are too coarse in resolution to inform watershed-scale management for Pacific Islands. To address this gap, we developed a novel linked land-sea modeling framework based on local data, which coupled groundwater and coral reef models at fine spatial resolution, to determine the effects of terrestrial drivers (groundwater and nutrients), mediated by human activities (land cover/use), and marine drivers (waves, geography, and habitat) on coral reefs. We applied this framework in two 'ridge-to-reef' systems (Hā'ena and Ka'ūpūlehu) subject to different natural disturbance regimes, located in the Hawaiian Archipelago. Our results indicated that coral reefs in Ka'ūpūlehu are coral-dominated with many grazers and scrapers due to low rainfall and wave power. While coral reefs in Hā'ena are dominated by crustose coralline algae with many grazers and less scrapers due to high rainfall and wave power. In general, Ka'ūpūlehu is more vulnerable to land-based nutrients and coral bleaching than Hā'ena due to high coral cover and limited dilution and mixing from low rainfall and wave power. However, the shallow and wave sheltered back-reef areas of Hā'ena, which support high coral cover and act as nursery habitat for fishes, are also vulnerable to land-based nutrients and coral bleaching. Anthropogenic sources of nutrients located upstream from these vulnerable areas are relevant locations for nutrient mitigation, such as cesspool upgrades. In this study, we located coral reefs vulnerable to land-based nutrients and linked them to priority areas to manage sources of human-derived nutrients, thereby demonstrating how this framework can inform place-based ridge-to-reef management.

Multiscale change in reef coral species diversity and composition in the Tropical Eastern Pacific

NASA Astrophysics Data System (ADS)

Gomez, Catalina G.; Gonzalez, Andrew; Guzman, Hector M.

2018-03-01

Both natural and anthropogenic factors are changing coral-reef structure and function worldwide. Long-term monitoring has revealed declines in the local composition and species diversity of reefs. Here we report changes in coral-reef community structure over 12 yr (2000-2012) at 17 sites and three spatial scales (reef, gulf and country) in the Tropical Eastern Pacific (Panama). We found a significant 4% annual decline in species population sizes at the country and gulf scales, with significant declines ranging from 3 to 32% at all but one reef. No significant temporal change in expected richness was found at the country scale or in the Gulf of Chiriquí, but a 7% annual decline in expected species richness was found in the Gulf of Panama. There was a 2% increase in community evenness in the Gulf of Chiriquí, but no change in the Gulf of Panama. Significant temporal turnover was found at the country and gulf scales and at 29% of the reefs, a finding mostly explained by changes in species abundance, and losses and gains of rare species. Temporal trends in alpha and beta diversity metrics were explained by water temperature maxima, anomalies and variation that occurred even in the absence of a strong El Niño warming event.

The modern deep water coral reefs off NW-Europe: the largest reef province in the world

NASA Astrophysics Data System (ADS)

Dullo, W. C.; Freiwald, A.

2003-04-01

Recently discovered deep-water coral reefs and coral mounds in the Procupine Seabight and in the Rockall Trough are part of a North Atlantic coral reef province, stretching from the Iberian Peninsula up to northern Norway within the intermediate water-mass. Current research activities underline the significance of these coral eco-systems as a centre of extreme high biodiversity and biomass indicated by numerous economically important nurtrients for humans as well as resources for marine biochemical products. This unexpected high biological activity along continental margins, which is responsible for the formation of 100 m high biogenic mounds, creating impressive geological reliefs, portrays the complex coupling between hydrosphere and geosphere. The geological importance of these recent and living carbonate structures is underlined by the fact that this "reef type" or mud mound is a very prominent carbon hydrogen reservoir throughout earth history. Such mud mound structures cannot be compared with any other present-day shallow water reef. Our present knowledge about reefs and carbonate production is limited to the areas of the shallow shelves mainly within the tropical region. Only few studies exist from high latitudes and from the continental margin of NW Europe. Further occurences of these deep-water mounds have recently been discovered off West Africa and off SE Brasilia within the frame of exploration activities. The portion of the climate-forcing greenhouse gas CO_2, stored in these mounds during glacial and interglacial times has not been introduced into model runs and prediction scenarios so far. These mounds do not depend on glacial/interglacial sea-level changes in the same way as their shallow-water counterparts do. Deep-water coral mounds react and respond to changes in the oceanographic regime and are triggered by abrupt changes within the sedimentary environment (increased erosion of shelf sediments during low stands of sea level as well as slope instabilities). These properties of modern aphotic coral mounds provide the ideal potential for the interpretation of fossil deep-water mounds in order to study their control mechanisms and their oceanographic environment.

Effects of seawater acidification on a coral reef meiofauna community

NASA Astrophysics Data System (ADS)

Sarmento, V. C.; Souza, T. P.; Esteves, A. M.; Santos, P. J. P.

2015-09-01

Despite the increasing risk that ocean acidification will modify benthic communities, great uncertainty remains about how this impact will affect the lower trophic levels, such as members of the meiofauna. A mesocosm experiment was conducted to investigate the effects of water acidification on a phytal meiofauna community from a coral reef. Community samples collected from the coral reef subtidal zone (Recife de Fora Municipal Marine Park, Porto Seguro, Bahia, Brazil), using artificial substrate units, were exposed to a control pH (ambient seawater) and to three levels of seawater acidification (pH reductions of 0.3, 0.6, and 0.9 units below ambient) and collected after 15 and 30 d. After 30 d of exposure, major changes in the structure of the meiofauna community were observed in response to reduced pH. The major meiofauna groups showed divergent responses to acidification. Harpacticoida and Polychaeta densities did not show significant differences due to pH. Nematoda, Ostracoda, Turbellaria, and Tardigrada exhibited their highest densities in low-pH treatments (especially at the pH reduction of 0.6 units, pH 7.5), while harpacticoid nauplii were strongly negatively affected by low pH. This community-based mesocosm study supports previous suggestions that ocean acidification induces important changes in the structure of marine benthic communities. Considering the importance of meiofauna in the food web of coral reef ecosystems, the results presented here demonstrate that the trophic functioning of coral reefs is seriously threatened by ocean acidification.

77 FR 19230 - Western Pacific Fishery Management Council; Public Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-30

.... Precious corals fishery and coral reef habitat status. iv. Update on Bio-Sampling Program data summary. v... precious coral fisheries. iv. Coral reef habitat status. v. Update on Bio-Sampling Program and Spearfishing... fisheries. iv. Precious corals fishery and coral reef habitat status. v. Update on Bio-Sampling Program Data...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saller, A.H.; Schlanger, S.O.

Two wells drilled along the margin of Enewetak Atoll penetrated approximately 1,000 m of upper eocene, Oligocene, and lower Miocene carbonates. STrontium isotope stratigraphy indicates relatively continuous deposition of carbonate from 40 Ma to 20 Ma. Depositional environments show a gradual basinward progradation of facies with slope carbonates passing upward into fore-reef, reef, back-reef, and lagoonal carbonates. Slope strata contain wackestones and packstones with submarine-cemented lithoclasts, coral, coralline algae fragments, benthic rotaline forams, planktonic forams, and echinoderm fragments. Fore-reef strata are dominantly packstones and boundstones containing large pieces of coral, abundant benthic forams, coralline algae fragments, stromatoporoids(.), and minor planktonicmore » forams. Reef and near-reef sediments include coralgal boundstones and grainstones with abundant benthic forams. Halimeda and miliolid forams are common in lagoonward parts of the back reef. Sponge borings, geopetal structures, and fractures are common in reef and fore-reef strata. Lagoonal strata are wackestones and packstones with common mollusks, coral, coralline algae, and benthic forams (rotaline and miliolid). Diagenesis has extensively altered strata near the atoll margin. Aragonite dissolution and calcite cements (radiaxial and cloudy prismatic are abundant in fore-reef, reef, and some back-reef strata). Petrographic and geochemical data indicate arogonite dissolution and calcite cementation in seawater at burial depths of 100 to 300 m. Dolomite occurs in slope and deeply buried reefal carbonates.« less

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

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. © 2017 The Authors.

Assessing the Effects of Disease and Bleaching on Florida Keys Corals by Fitting Population Models to Data

EPA Science Inventory

Coral diseases have increased in frequency over the past few decades and have important influences on the structure and composition of coral reef communities. However, there is limited information on the etiologies of many coral diseases, and pathways via which coral diseases ar...

75 FR 14571 - Western Pacific Fishery Management Council; Public Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-26

... for bottomfish, coral reef, precious coral and crustacean fisheries. Reports will be provided on... Archipelago Fishery Ecosystem Plan Annual Report Modules for bottomfish, coral reef, precious coral and..., sea turtle interaction mitigation in the American Samoa longline Fishery, DMWR coral reef ecosystem...

A deep reef in deep trouble

USGS Publications Warehouse

Menza, Charles; Kendall, M.; Rogers, C.; Miller, J.

2007-01-01

The well-documented degradation of shallower reefs which are often closer to land and more vulnerable to pollution, sewage and other human-related stressors has led to the suggestion that deeper, more remote offshore reefs could possibly serve as sources of coral and fish larvae to replenish the shallower reefs. Yet, the distribution, status, and ecological roles of deep (>30 m) Caribbean reefs are not well known. In this report, an observation of a deep reef which has undergone a recent extensive loss of coral cover is presented. In stark contrast to the typical pattern of coral loss in shallow reefs, the deeper corals were most affected. This report is the first description of such a pattern of coral loss on a deep reef.

The Ecological Role of Sharks on Coral Reefs.

PubMed

Roff, George; Doropoulos, Christopher; Rogers, Alice; Bozec, Yves-Marie; Krueck, Nils C; Aurellado, Eleanor; Priest, Mark; Birrell, Chico; Mumby, Peter J

2016-05-01

Sharks are considered the apex predator of coral reefs, but the consequences of their global depletion are uncertain. Here we explore the ecological roles of sharks on coral reefs and, conversely, the importance of reefs for sharks. We find that most reef-associated shark species do not act as apex predators but instead function as mesopredators along with a diverse group of reef fish. While sharks perform important direct and indirect ecological roles, the evidence to support hypothesised shark-driven trophic cascades that benefit corals is weak and equivocal. Coral reefs provide some functional benefits to sharks, but sharks do not appear to favour healthier reef environments. Restoring populations of sharks is important and can yet deliver ecological surprise. Copyright © 2016 Elsevier Ltd. All rights reserved.

Benthic status of near-shore fishing grounds in the central Philippines and associated seahorse densities.

PubMed

Marcus, J E; Samoilys, M A; Meeuwig, J J; Villongco, Z A D; Vincent, A C J

2007-09-01

Benthic status of 28 near-shore, artisanal, coral reef fishing grounds in the central Philippines was assessed (2000-2002) together with surveys of the seahorse, Hippocampus comes. Our measures of benthic quality and seahorse densities reveal some of the most degraded coral reefs in the world. Abiotic structure dominated the fishing grounds: 69% of the benthos comprised rubble (32%), sand/silt (28%) and dead coral (9%). Predominant biotic structure included live coral (12%) and Sargassum (11%). Rubble cover increased with increasing distance from municipal enforcement centers and coincided with substantial blast fishing in this region of the Philippines. Over 2 years, we measured a significant decrease in benthic 'heterogeneity' and a 16% increase in rubble cover. Poor benthic quality was concomitant with extremely low seahorse densities (524 fish per km(2)). Spatial management, such as marine reserves, may help to minimize habitat damage and to rebuild depleted populations of seahorses and other reef fauna.

50 CFR 665.124 - Permits and fees.

Code of Federal Regulations, 2014 CFR

2014-10-01

... retaining American Samoa coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) American Samoa coral reef ecosystem MUS in low-use MPAs as defined in § 665.99; (ii) American Samoa Potentially Harvested Coral Reef Taxa in the coral reef ecosystem...

50 CFR 665.124 - Permits and fees.

Code of Federal Regulations, 2013 CFR

2013-10-01

... retaining American Samoa coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) American Samoa coral reef ecosystem MUS in low-use MPAs as defined in § 665.99; (ii) American Samoa Potentially Harvested Coral Reef Taxa in the coral reef ecosystem...

50 CFR 665.424 - Permits and fees.

Code of Federal Regulations, 2012 CFR

2012-10-01

... retaining Mariana coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Mariana coral reef ecosystem MUS in low-use MPAs as defined in § 665.399; (ii) Mariana Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area...

50 CFR 665.124 - Permits and fees.

Code of Federal Regulations, 2012 CFR

2012-10-01

... retaining American Samoa coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) American Samoa coral reef ecosystem MUS in low-use MPAs as defined in § 665.99; (ii) American Samoa Potentially Harvested Coral Reef Taxa in the coral reef ecosystem...

50 CFR 665.424 - Permits and fees.

Code of Federal Regulations, 2014 CFR

2014-10-01

... retaining Mariana coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Mariana coral reef ecosystem MUS in low-use MPAs as defined in § 665.399; (ii) Mariana Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area...

50 CFR 665.424 - Permits and fees.

Code of Federal Regulations, 2013 CFR

2013-10-01

... retaining Mariana coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Mariana coral reef ecosystem MUS in low-use MPAs as defined in § 665.399; (ii) Mariana Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area...

50 CFR 665.124 - Permits and fees.

Code of Federal Regulations, 2011 CFR

2011-10-01

... retaining American Samoa coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) American Samoa coral reef ecosystem MUS in low-use MPAs as defined in § 665.99; (ii) American Samoa Potentially Harvested Coral Reef Taxa in the coral reef ecosystem...

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…

50 CFR 665.424 - Permits and fees.

Code of Federal Regulations, 2010 CFR

2010-10-01

... retaining Mariana coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Mariana coral reef ecosystem MUS in low-use MPAs as defined in § 665.399; (ii) Mariana Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area...

50 CFR 665.424 - Permits and fees.

Code of Federal Regulations, 2011 CFR

2011-10-01

... retaining Mariana coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Mariana coral reef ecosystem MUS in low-use MPAs as defined in § 665.399; (ii) Mariana Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area...

78 FR 16296 - Record of Decision for the Coral Reef Restoration Plan, Biscayne National Park, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-14

...] Record of Decision for the Coral Reef Restoration Plan, Biscayne National Park, FL AGENCY: National Park... Record of Decision (ROD) for the Coral Reef Restoration Plan (Plan) for Biscayne National Park, Florida... Biscayne National Park, causing injuries to submerged resources. The goal of coral reef restoration actions...

50 CFR 665.124 - Permits and fees.

Code of Federal Regulations, 2010 CFR

2010-10-01

... retaining American Samoa coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) American Samoa coral reef ecosystem MUS in low-use MPAs as defined in § 665.99; (ii) American Samoa Potentially Harvested Coral Reef Taxa in the coral reef ecosystem...

Mass coral bleaching in 2010 in the southern Caribbean.

PubMed

Alemu I, Jahson Berhane; Clement, Ysharda

2014-01-01

Ocean temperatures are increasing globally and the Caribbean is no exception. An extreme ocean warming event in 2010 placed Tobago's coral reefs under severe stress resulting in widespread coral bleaching and threatening the livelihoods that rely on them. The bleaching response of four reef building taxa was monitored over a six month period across three major reefs systems in Tobago. By identifying taxa resilient to bleaching we propose to assist local coral reef managers in the decision making process to cope with mass bleaching events. The bleaching signal (length of exposure to high ocean temperatures) varied widely between the Atlantic and Caribbean reefs, but regardless of this variation most taxa bleached. Colpophyllia natans, Montastraea faveolata and Siderastrea siderea were considered the most bleaching vulnerable taxa. Interestingly, reefs with the highest coral cover showed the greatest decline reef building taxa, and conversely, reefs with the lowest coral cover showed the most bleaching but lowest change in coral cover with little algal overgrowth post-bleaching.

Mass Coral Bleaching in 2010 in the Southern Caribbean

PubMed Central

Alemu I, Jahson Berhane; Clement, Ysharda

2014-01-01

Ocean temperatures are increasing globally and the Caribbean is no exception. An extreme ocean warming event in 2010 placed Tobago's coral reefs under severe stress resulting in widespread coral bleaching and threatening the livelihoods that rely on them. The bleaching response of four reef building taxa was monitored over a six month period across three major reefs systems in Tobago. By identifying taxa resilient to bleaching we propose to assist local coral reef managers in the decision making process to cope with mass bleaching events. The bleaching signal (length of exposure to high ocean temperatures) varied widely between the Atlantic and Caribbean reefs, but regardless of this variation most taxa bleached. Colpophyllia natans, Montastraea faveolata and Siderastrea siderea were considered the most bleaching vulnerable taxa. Interestingly, reefs with the highest coral cover showed the greatest decline reef building taxa, and conversely, reefs with the lowest coral cover showed the most bleaching but lowest change in coral cover with little algal overgrowth post-bleaching. PMID:24400078

U-Th dating reveals regional-scale decline of branching Acropora corals on the Great Barrier Reef over the past century

PubMed Central

Clark, Tara R.; Roff, George; Zhao, Jian-xin; Feng, Yue-xing; Done, Terence J.; McCook, Laurence J.; Pandolfi, John M.

2017-01-01

Hard coral cover on the Great Barrier Reef (GBR) is on a trajectory of decline. However, little is known about past coral mortality before the advent of long-term monitoring (circa 1980s). Using paleoecological analysis and high-precision uranium-thorium (U-Th) dating, we reveal an extensive loss of branching Acropora corals and changes in coral community structure in the Palm Islands region of the central GBR over the past century. In 2008, dead coral assemblages were dominated by large, branching Acropora and living coral assemblages by genera typically found in turbid inshore environments. The timing of Acropora mortality was found to be occasionally synchronous among reefs and frequently linked to discrete disturbance events, occurring in the 1920s to 1960s and again in the 1980s to 1990s. Surveys conducted in 2014 revealed low Acropora cover (<5%) across all sites, with very little evidence of change for up to 60 y at some sites. Collectively, our results suggest a loss of resilience of this formerly dominant key framework builder at a regional scale, with recovery severely lagging behind predictions. Our study implies that the management of these reefs may be predicated on a shifted baseline. PMID:28893981

U-Th dating reveals regional-scale decline of branching Acropora corals on the Great Barrier Reef over the past century.

PubMed

Clark, Tara R; Roff, George; Zhao, Jian-Xin; Feng, Yue-Xing; Done, Terence J; McCook, Laurence J; Pandolfi, John M

2017-09-26

Hard coral cover on the Great Barrier Reef (GBR) is on a trajectory of decline. However, little is known about past coral mortality before the advent of long-term monitoring (circa 1980s). Using paleoecological analysis and high-precision uranium-thorium (U-Th) dating, we reveal an extensive loss of branching Acropora corals and changes in coral community structure in the Palm Islands region of the central GBR over the past century. In 2008, dead coral assemblages were dominated by large, branching Acropora and living coral assemblages by genera typically found in turbid inshore environments. The timing of Acropora mortality was found to be occasionally synchronous among reefs and frequently linked to discrete disturbance events, occurring in the 1920s to 1960s and again in the 1980s to 1990s. Surveys conducted in 2014 revealed low Acropora cover (<5%) across all sites, with very little evidence of change for up to 60 y at some sites. Collectively, our results suggest a loss of resilience of this formerly dominant key framework builder at a regional scale, with recovery severely lagging behind predictions. Our study implies that the management of these reefs may be predicated on a shifted baseline.

U-Th dating reveals regional-scale decline of branching Acropora corals on the Great Barrier Reef over the past century

NASA Astrophysics Data System (ADS)

Clark, Tara R.; Roff, George; Zhao, Jian-xin; Feng, Yue-xing; Done, Terence J.; McCook, Laurence J.; Pandolfi, John M.

2017-09-01

Hard coral cover on the Great Barrier Reef (GBR) is on a trajectory of decline. However, little is known about past coral mortality before the advent of long-term monitoring (circa 1980s). Using paleoecological analysis and high-precision uranium-thorium (U-Th) dating, we reveal an extensive loss of branching Acropora corals and changes in coral community structure in the Palm Islands region of the central GBR over the past century. In 2008, dead coral assemblages were dominated by large, branching Acropora and living coral assemblages by genera typically found in turbid inshore environments. The timing of Acropora mortality was found to be occasionally synchronous among reefs and frequently linked to discrete disturbance events, occurring in the 1920s to 1960s and again in the 1980s to 1990s. Surveys conducted in 2014 revealed low Acropora cover (<5%) across all sites, with very little evidence of change for up to 60 y at some sites. Collectively, our results suggest a loss of resilience of this formerly dominant key framework builder at a regional scale, with recovery severely lagging behind predictions. Our study implies that the management of these reefs may be predicated on a shifted baseline.

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.

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.

Coral mucus functions as an energy carrier and particle trap in the reef ecosystem.

PubMed

Wild, Christian; Huettel, Markus; Klueter, Anke; Kremb, Stephan G; Rasheed, Mohammed Y M; Jørgensen, Bo B

2004-03-04

Zooxanthellae, endosymbiotic algae of reef-building corals, substantially contribute to the high gross primary production of coral reefs, but corals exude up to half of the carbon assimilated by their zooxanthellae as mucus. Here we show that released coral mucus efficiently traps organic matter from the water column and rapidly carries energy and nutrients to the reef lagoon sediment, which acts as a biocatalytic mineralizing filter. In the Great Barrier Reef, the dominant genus of hard corals, Acropora, exudes up to 4.8 litres of mucus per square metre of reef area per day. Between 56% and 80% of this mucus dissolves in the reef water, which is filtered through the lagoon sands. Here, coral mucus is degraded at a turnover rate of at least 7% per hour. Detached undissolved mucus traps suspended particles, increasing its initial organic carbon and nitrogen content by three orders of magnitude within 2 h. Tidal currents concentrate these mucus aggregates into the lagoon, where they rapidly settle. Coral mucus provides light energy harvested by the zooxanthellae and trapped particles to the heterotrophic reef community, thereby establishing a recycling loop that supports benthic life, while reducing loss of energy and nutrients from the reef ecosystem.

Coral reef monitoring in the Iles Eparses, Mozambique Channel (2011-2013)

NASA Astrophysics Data System (ADS)

Chabanet, P.; Bigot, L.; Nicet, J.-B.; Durville, P.; Massé, L.; Mulochau, T.; Russo, C.; Tessier, E.; Obura, D.

2016-04-01

Monitoring of coral reefs has become a major tool for understanding how they are changing, and for managing them in a context of increasing degradation of coastal ecosystems. The Global Coral Reef Monitoring Network (GCRMN) has near-global coverage, but there are few remote sites free of direct human impact that can serve as reference sites. This study provides baseline data for the French Iles Eparses in the Mozambique Channel, Western Indian Ocean (WIO), whose coral reefs are little known owing to their limited accessibility, and have been free from fishing pressure for over 20 years. Surveys of coral reef health and fish community structure were undertaken at four of the islands (Europa, Bassas da India, Juan de Nova and Glorieuses) in 2011-2013. Monitoring was conducted using standardized GCRMN methods for benthos and fish communities, at the highest taxonomic level. Benthic cover showed a latitudinal gradient, with higher coral cover and conversely lower algae cover (60% and 14% respectively) in the south of the Mozambique Channel. This could be due to the geomorphology of the islands, the latitudinal temperature gradient, and/or the history of chronic stress and bleaching events during the last decades. Fish also showed a latitudinal gradient with higher diversity in the north, in a center of diversity for the western Indian Ocean already recognized for corals. An exceptional biomass fish was recorded (approximately 3500 kg/ha excluding sharks, compared to a maximum of 1400 kg/ha elsewhere in the WIO). The presence of large predators and sharks in all the islands as well as the absence of fleshy benthic algae were indicators of the good health of the reef systems. Nevertheless, these islands are beginning to experience illegal fishing, particularly in the north of the Mozambique Channel, demonstrating their vulnerability to exploitation and the need to protect them as reference sites for coral reef studies, including of climate change impacts, for the region and globally.

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.

Coral reefs promote the evolution of morphological diversity and ecological novelty in labrid fishes.

PubMed

Price, S A; Holzman, R; Near, T J; Wainwright, P C

2011-05-01

Although coral reefs are renowned biodiversity hotspots it is not known whether they also promote the evolution of exceptional ecomorphological diversity. We investigated this question by analysing a large functional morphological dataset of trophic characters within Labridae, a highly diverse group of fishes. Using an analysis that accounts for species relationships, the time available for diversification and model uncertainty we show that coral reef species have evolved functional morphological diversity twice as fast as non-reef species. In addition, coral reef species occupy 68.6% more trophic morphospace than non-reef species. Our results suggest that coral reef habitats promote the evolution of both trophic novelty and morphological diversity within fishes. Thus, the preservation of coral reefs is necessary, not only to safeguard current biological diversity but also to conserve the underlying mechanisms that can produce functional diversity in future. © 2011 Blackwell Publishing Ltd/CNRS.

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

EPA Pesticide Factsheets

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

Variability in the phytoplankton community of Kavaratti reef ecosystem (northern Indian Ocean) during peak and waning periods of El Niño 2016.

PubMed

Karati, Kusum Komal; Vineetha, G; Madhu, N V; Anil, P; Dayana, M; Shihab, B K; Muhsin, A I; Riyas, C; Raveendran, T V

2017-11-29

El Niño, an interannual climate event characterized by elevated oceanic temperature, is a prime threat for coral reef ecosystems worldwide, owing to their thermal threshold sensitivity. Phytoplankton plays a crucial role in the sustenance of reef trophodynamics. The cell size of the phytoplankton forms the "master morphological trait" with implications for growth, resource acquisition, and adaptability to nutrients. In the context of a strong El Niño prediction for 2015-2016, the present study was undertaken to evaluate the variations in the size-structured phytoplankton of Kavaratti reef waters, a major coral atoll along the southeast coast of India. The present study witnessed a remarkable change in the physicochemical environment of the reef water and massive coral bleaching with the progression of El Niño 2015-2016 from its peak to waning phase. The fluctuations observed in sea surface temperature, pH, and nutrient concentration of the reef water with the El Niño progression resulted in a remarkable shift in phytoplankton size structure, abundance, and community composition of the reef waters. Though low nutrient concentration of the waning phase resulted in lower phytoplankton biomass and abundance, the diazotroph Trichodesmium erythraeum predominated the reef waters, owing to its capability of the atmospheric nitrogen fixation and dissolved organic phosphate utilization.

Secondary calcification and dissolution respond differently to future ocean conditions

NASA Astrophysics Data System (ADS)

Silbiger, N. J.; Donahue, M. J.

2015-01-01

Climate change threatens both the accretion and erosion processes that sustain coral reefs. Secondary calcification, bioerosion, and reef dissolution are integral to the structural complexity and long-term persistence of coral reefs, yet these processes have received less research attention than reef accretion by corals. In this study, we use climate scenarios from RCP 8.5 to examine the combined effects of rising ocean acidity and sea surface temperature (SST) on both secondary calcification and dissolution rates of a natural coral rubble community using a flow-through aquarium system. We found that secondary reef calcification and dissolution responded differently to the combined effect of pCO2 and temperature. Calcification had a non-linear response to the combined effect of pCO2 and temperature: the highest calcification rate occurred slightly above ambient conditions and the lowest calcification rate was in the highest temperature-pCO2 condition. In contrast, dissolution increased linearly with temperature-pCO2 . The rubble community switched from net calcification to net dissolution at +271 μatm pCO2 and 0.75 °C above ambient conditions, suggesting that rubble reefs may shift from net calcification to net dissolution before the end of the century. Our results indicate that (i) dissolution may be more sensitive to climate change than calcification and (ii) that calcification and dissolution have different functional responses to climate stressors; this highlights the need to study the effects of climate stressors on both calcification and dissolution to predict future changes in coral reefs.

Secondary calcification and dissolution respond differently to future ocean conditions

NASA Astrophysics Data System (ADS)

Silbiger, N. J.; Donahue, M. J.

2014-09-01

Climate change threatens both the accretion and erosion processes that sustain coral reefs. Secondary calcification, bioerosion, and reef dissolution are integral to the structural complexity and long-term persistence of coral reefs, yet these processes have received less research attention than reef accretion by corals. In this study, we use climate scenarios from RCP8.5 to examine the combined effects of rising ocean acidity and SST on both secondary calcification and dissolution rates of a natural coral rubble community using a flow-through aquarium system. We found that secondary reef calcification and dissolution responded differently to the combined effect of pCO2 and temperature. Calcification had a non-linear response to the combined effect of pCO2-temperature: the highest calcification rate occurred slightly above ambient conditions and the lowest calcification rate was in the highest pCO2-temperature condition. In contrast, dissolution increased linearly with pCO2-temperature. The rubble community switched from net calcification to net dissolution at +272 μatm pCO2 and 0.84 °C above ambient conditions, suggesting that rubble reefs may shift from net calcification to net dissolution before the end of the century. Our results indicate that dissolution may be more sensitive to climate change than calcification, and that calcification and dissolution have different functional responses to climate stressors, highlighting the need to study the effects of climate stressors on both calcification and dissolution to predict future changes in coral reefs.

Coexistence of low coral cover and high fish biomass at Farquhar Atoll, Seychelles.

PubMed

Friedlander, Alan M; Obura, David; Aumeeruddy, Riaz; Ballesteros, Enric; Church, Julie; Cebrian, Emma; Sala, Enric

2014-01-01

We report a reef ecosystem where corals may have lost their role as major reef engineering species but fish biomass and assemblage structure is comparable to unfished reefs elsewhere around the world. This scenario is based on an extensive assessment of the coral reefs of Farquhar Atoll, the most southern of the Seychelles Islands. Coral cover and overall benthic community condition at Farquhar was poor, likely due to a combination of limited habitat, localized upwelling, past coral bleaching, and cyclones. Farquhar Atoll harbors a relatively intact reef fish assemblage with very large biomass (3.2 t ha(-1)) reflecting natural ecological processes that are not influenced by fishing or other local anthropogenic factors. The most striking feature of the reef fish assemblage is the dominance by large groupers, snappers, and jacks with large (>1 m) potato cod (Epinephelus tukula) and marbled grouper (E. polyphekadion), commonly observed at many locations. Napoleon wrasse (Cheilinus undulatus) and bumphead parrotfish (Bolbometopon muricatum) are listed as endangered and vulnerable, respectively, but were frequently encountered at Farquhar. The high abundance and large sizes of parrotfishes at Farquhar also appears to regulate macroalgal abundance and enhance the dominance of crustose corallines, which are a necessary condition for maintenance of healthy reef communities. Overall fish biomass and biomass of large predators at Farquhar are substantially higher than other areas within the Seychelles, and are some of the highest recorded in the Indian Ocean. Remote islands like Farquhar Atoll with low human populations and limited fishing pressure offer ideal opportunities for understanding whether reefs can be resilient from global threats if local threats are minimized.

The non-linear relationship between body size and function in parrotfishes

NASA Astrophysics Data System (ADS)

Lokrantz, J.; Nyström, M.; Thyresson, M.; Johansson, C.

2008-12-01

Parrotfishes are a group of herbivores that play an important functional role in structuring benthic communities on coral reefs. Increasingly, these fish are being targeted by fishermen, and resultant declines in biomass and abundance may have severe consequences for the dynamics and regeneration of coral reefs. However, the impact of overfishing extends beyond declining fish stocks. It can also lead to demographic changes within species populations where mean body size is reduced. The effect of reduced mean body size on population dynamics is well described in literature but virtually no information exists on how this may influence important ecological functions. The study investigated how one important function, scraping (i.e., the capacity to remove algae and open up bare substratum for coral larval settlement), by three common species of parrotfishes ( Scarus niger, Chlorurus sordidus, and Chlorurus strongylocephalus) on coral reefs at Zanzibar (Tanzania) was influenced by the size of individual fishes. There was a non-linear relationship between body size and scraping function for all species examined, and impact through scraping was also found to increase markedly when fish reached a size of 15 20 cm. Thus, coral reefs which have a high abundance and biomass of parrotfish may nonetheless be functionally impaired if dominated by small-sized individuals. Reductions in mean body size within parrotfish populations could, therefore, have functional impacts on coral reefs that previously have been overlooked.

76 FR 16618 - Western Pacific Fishery Management Council; Public Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-24

... Programs and Research Projects A. Coral Reef Fisheries B. Crustacean Fisheries C. Precious Coral Fisheries... Offshore Aquaculture 7. Coral Reef Funded Projects A. Kona Crab Stock Assessment B. Black Coral Mapping C. Deepwater Chorusing Phenomenon D. Report on Tournament Sampling E. Upcoming Coral Reef Projects Schedule and...

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. © 2015 John Wiley & Sons Ltd.

Closing the circle: is it feasible to rehabilitate reefs with sexually propagated corals?

NASA Astrophysics Data System (ADS)

Guest, J. R.; Baria, M. V.; Gomez, E. D.; Heyward, A. J.; Edwards, A. J.

2014-03-01

Sexual propagation of corals specifically for reef rehabilitation remains largely experimental. In this study, we refined low technology culture and transplantation approaches and assessed the role of colony size and age, at time of transfer from nursery to reef, on subsequent survival. Larvae from Acropora millepora were reared from gametes and settled on engineered substrates, called coral plug-ins, that were designed to simplify transplantation to areas of degraded reef. Plug-ins, with laboratory spawned and settled coral recruits attached, were maintained in nurseries until they were at least 7 months old before being transplanted to replicate coral limestone outcrops within a marine protected area until they were 31 months old. Survival rates of transplanted corals that remained at the protected in situ nursery the longest were 3.9-5.6 times higher than corals transplanted to the reef earlier, demonstrating that an intermediate ocean nursery stage is critical in the sexual propagation of corals for reef rehabilitation. 3 years post-settlement, colonies were reproductively mature, making this one of few published studies to date to rear a broadcasting scleractinian from eggs to spawning adults. While our data show that it is technically feasible to transplant sexually propagated corals and rear them until maturity, producing a single 2.5-year-old coral on the reef cost at least US60. `What if' scenarios indicate that the cost per transplantable coral could be reduced by almost 80 %, nevertheless, it is likely that the high cost per coral using sexual propagation methods would constrain delivery of new corals to relatively small scales in many countries with coral reefs.

50 CFR 665.224 - Permits and fees.

Code of Federal Regulations, 2012 CFR

2012-10-01

... retaining Hawaii coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Hawaii coral reef ecosystem MUS in low-use MPAs as defined in § 665.199; (ii) Hawaii Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area; or (iii...

50 CFR 665.224 - Permits and fees.

Code of Federal Regulations, 2014 CFR

2014-10-01

... retaining Hawaii coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Hawaii coral reef ecosystem MUS in low-use MPAs as defined in § 665.199; (ii) Hawaii Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area; or (iii...

50 CFR 665.224 - Permits and fees.

Code of Federal Regulations, 2013 CFR

2013-10-01

... retaining Hawaii coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Hawaii coral reef ecosystem MUS in low-use MPAs as defined in § 665.199; (ii) Hawaii Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area; or (iii...

76 FR 52318 - U.S. Coral Reef Task Force Public Meeting and Public Comment

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-22

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration U.S. Coral Reef Task Force... of the U.S. Coral Reef Task Force. The meeting will be held in Ft. Lauderdale, Florida. This meeting, the 26th bi-annual meeting of the U.S. Coral Reef Task Force, provides a forum for coordinated...

76 FR 59373 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Generic Annual Catch Limits...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-26

... Fishery Management Plans (FMPs) for Reef Fish Resources, Red Drum, Shrimp, and Coral and Coral Reefs for... Coral and Coral Reefs FMP. The majority of harvest of octocorals occurs in waters under the jurisdiction... commercial and recreational sectors within the reef fish fishery in the Gulf. Finally, the Generic ACL...

77 FR 39724 - U.S. Coral Reef Task Force Public Meeting and Public Comment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-05

...-DS61200000] U.S. Coral Reef Task Force Public Meeting and Public Comment AGENCY: Fish and Wildlife Service... Wildlife Service (Service), announce a public meeting of the U.S. Coral Reef Task Force (USCRTF) and a... strengthen U.S. government actions to better preserve and protect coral reef ecosystems. The Departments of...

76 FR 7579 - U.S. Coral Reef Task Force Public Meeting and Public Comment

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-10

.... Coral Reef Task Force Public Meeting and Public Comment AGENCY: Fish and Wildlife Service, Interior... Service (Service), announce a public business meeting of the U.S. Coral Reef Task Force (USCRTF) [email protected] ); or Liza Johnson, U.S. Coral Reef Task Force Department of the Interior Liaison, U.S...

50 CFR 665.224 - Permits and fees.

Code of Federal Regulations, 2010 CFR

2010-10-01

... retaining Hawaii coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Hawaii coral reef ecosystem MUS in low-use MPAs as defined in § 665.199; (ii) Hawaii Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area; or (iii...

50 CFR 665.224 - Permits and fees.

Code of Federal Regulations, 2011 CFR

2011-10-01

... retaining Hawaii coral reef ecosystem MUS must have a special permit if they, or a vessel which they operate, is used to fish for any: (i) Hawaii coral reef ecosystem MUS in low-use MPAs as defined in § 665.199; (ii) Hawaii Potentially Harvested Coral Reef Taxa in the coral reef ecosystem management area; or (iii...

Workshop on Biological Integrity of Coral Reefs August 21-22, 2012, Caribbean Coral Reef Institute, Isla Magueyes, La Parguera, Puerto Rico.

EPA Science Inventory

This report summarizes an EPA-sponsored workshop on coral reef biological integrity held at the Caribbean Coral Reef Institute in La Parguera, Puerto Rico on August 21-22, 2012. The goals of this workshop were to:• Identify key qualitative and quantitative ecological characterist...

Evidence of photosymbiosis in Palaeozoic tabulate corals.

PubMed

Zapalski, Mikolaj K

2014-01-22

Coral reefs form the most diverse of all marine ecosystems on the Earth. Corals are among their main components and owe their bioconstructing abilities to a symbiosis with algae (Symbiodinium). The coral-algae symbiosis had been traced back to the Triassic (ca 240 Ma). Modern reef-building corals (Scleractinia) appeared after the Permian-Triassic crisis; in the Palaeozoic, some of the main reef constructors were extinct tabulate corals. The calcium carbonate secreted by extant photosymbiotic corals bears characteristic isotope (C and O) signatures. The analysis of tabulate corals belonging to four orders (Favositida, Heliolitida, Syringoporida and Auloporida) from Silurian to Permian strata of Europe and Africa shows these characteristic carbon and oxygen stable isotope signatures. The δ(18)O to δ(13)C ratios in recent photosymbiotic scleractinians are very similar to those of Palaeozoic tabulates, thus providing strong evidence of such symbioses as early as the Middle Silurian (ca 430 Ma). Corals in Palaeozoic reefs used the same cellular mechanisms for carbonate secretion as recent reefs, and thus contributed to reef formation.

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

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.

Consistent nutrient storage and supply mediated by diverse fish communities in coral reef ecosystems.

PubMed

Allgeier, Jacob E; Layman, Craig A; Mumby, Peter J; Rosemond, Amy D

2014-08-01

Corals thrive in low nutrient environments and the conservation of these globally imperiled ecosystems is largely dependent on mitigating the effects of anthropogenic nutrient enrichment. However, to better understand the implications of anthropogenic nutrients requires a heightened understanding of baseline nutrient dynamics within these ecosystems. Here, we provide a novel perspective on coral reef nutrient dynamics by examining the role of fish communities in the supply and storage of nitrogen (N) and phosphorus (P). We quantified fish-mediated nutrient storage and supply for 144 species and modeled these data onto 172 fish communities (71 729 individual fish), in four types of coral reefs, as well as seagrass and mangrove ecosystems, throughout the Northern Antilles. Fish communities supplied and stored large quantities of nutrients, with rates varying among ecosystem types. The size structure and diversity of the fish communities best predicted N and P supply and storage and N : P supply, suggesting that alterations to fish communities (e.g., overfishing) will have important implications for nutrient dynamics in these systems. The stoichiometric ratio (N : P) for storage in fish mass (~8 : 1) and supply (~20 : 1) was notably consistent across the four coral reef types (but not seagrass or mangrove ecosystems). Published nutrient enrichment studies on corals show that deviations from this N : P supply ratio may be associated with poor coral fitness, providing qualitative support for the hypothesis that corals and their symbionts may be adapted to specific ratios of nutrient supply. Consumer nutrient stoichiometry provides a baseline from which to better understand nutrient dynamics in coral reef and other coastal ecosystems, information that is greatly needed if we are to implement more effective measures to ensure the future health of the world's oceans. © 2014 John Wiley & Sons Ltd.

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.

Polymorphic Microsatellite Loci for Endemic Mussismilia Corals (Anthozoa: Scleractinia) of the Southwest Atlantic Ocean.

PubMed

Zilberberg, Carla; Peluso, Lívia; Marques, Jessica A; Cunha, Haydée

2014-01-01

In the Southwest Atlantic, coral reefs are unique due to their growth form, low species richness, and a high level of endemic coral species, which include the most important reef builders. Although these reefs are the only true biogenic reefs in the South Atlantic Ocean, population genetic studies are still lacking. The purpose of this study was to develop a suite of microsatellite loci to help gain insights into the population diversity and connectivity of the endemic scleractinian coral with the largest distributional range along the Southwest Atlantic coast, Mussismilia hispida Fourteen microsatellite loci were characterized, and their degree of polymorphism was analyzed in 33 individuals. The number of alleles varied between 4 and 17 per loci, and H o varied between 0.156 and 0.928, with 2 loci showing significant heterozygote deficiency. Cross-amplification tests on the other 2 species of the genus (Mussismilia braziliensis and Mussismilia harttii) demonstrated that these markers are suitable for studies of population diversity and structure of all 3 species of Mussismilia Because they are the most important reef builders in the Southwest Atlantic, the developed microsatellite loci may be important tools for connectivity and conservation studies of these endemic corals. © The American Genetic Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effect of Phase Shift from Corals to Zoantharia on Reef Fish Assemblages

PubMed Central

Cruz, Igor C. S.; Loiola, Miguel; Albuquerque, Tiago; Reis, Rodrigo; de Anchieta C. C. Nunes, José; Reimer, James D.; Mizuyama, Masaru; Kikuchi, Ruy K. P.; Creed, Joel C.

2015-01-01

Consequences of reef phase shifts on fish communities remain poorly understood. Studies on the causes, effects and consequences of phase shifts on reef fish communities have only been considered for coral-to-macroalgae shifts. Therefore, there is a large information gap regarding the consequences of novel phase shifts and how these kinds of phase shifts impact on fish assemblages. This study aimed to compare the fish assemblages on reefs under normal conditions (relatively high cover of corals) to those which have shifted to a dominance of the zoantharian Palythoa cf. variabilis on coral reefs in Todos os Santos Bay (TSB), Brazilian eastern coast. We examined eight reefs, where we estimated cover of corals and P. cf. variabilis and coral reef fish richness, abundance and body size. Fish richness differed significantly between normal reefs (48 species) and phase-shift reefs (38 species), a 20% reduction in species. However there was no difference in fish abundance between normal and phase shift reefs. One fish species, Chaetodon striatus, was significantly less abundant on normal reefs. The differences in fish assemblages between different reef phases was due to differences in trophic groups of fish; on normal reefs carnivorous fishes were more abundant, while on phase shift reefs mobile invertivores dominated. PMID:25629532

Archaeal and Bacterial Communities Associated with the Surface Mucus of Caribbean Corals Differ in Their Degree of Host Specificity and Community Turnover Over Reefs.

PubMed

Frade, Pedro R; Roll, Katharina; Bergauer, Kristin; Herndl, Gerhard J

2016-01-01

Comparative studies on the distribution of archaeal versus bacterial communities associated with the surface mucus layer of corals have rarely taken place. It has therefore remained enigmatic whether mucus-associated archaeal and bacterial communities exhibit a similar specificity towards coral hosts and whether they vary in the same fashion over spatial gradients and between reef locations. We used microbial community profiling (terminal-restriction fragment length polymorphism, T-RFLP) and clone library sequencing of the 16S rRNA gene to compare the diversity and community structure of dominant archaeal and bacterial communities associating with the mucus of three common reef-building coral species (Porites astreoides, Siderastrea siderea and Orbicella annularis) over different spatial scales on a Caribbean fringing reef. Sampling locations included three reef sites, three reef patches within each site and two depths. Reference sediment samples and ambient water were also taken for each of the 18 sampling locations resulting in a total of 239 samples. While only 41% of the bacterial operational taxonomic units (OTUs) characterized by T-RFLP were shared between mucus and the ambient water or sediment, for archaeal OTUs this percentage was 2-fold higher (78%). About half of the mucus-associated OTUs (44% and 58% of bacterial and archaeal OTUs, respectively) were shared between the three coral species. Our multivariate statistical analysis (ANOSIM, PERMANOVA and CCA) showed that while the bacterial community composition was determined by habitat (mucus, sediment or seawater), host coral species, location and spatial distance, the archaeal community composition was solely determined by the habitat. This study highlights that mucus-associated archaeal and bacterial communities differ in their degree of community turnover over reefs and in their host-specificity.

Impact of warming events on reef-scale temperature variability as captured in two Little Cayman coral Sr/Ca records

NASA Astrophysics Data System (ADS)

von Reumont, J.; Hetzinger, S.; Garbe-Schönberg, D.; Manfrino, C.; Dullo, W.-Chr.

2016-03-01

The rising temperature of the world's oceans is affecting coral reef ecosystems by increasing the frequency and severity of bleaching and mortality events. The susceptibility of corals to temperature stress varies on local and regional scales. Insights into potential controlling parameters are hampered by a lack of long term in situ data in most coral reef environments and sea surface temperature (SST) products often do not resolve reef-scale variations. Here we use 42 years (1970-2012) of coral Sr/Ca data to reconstruct seasonal- to decadal-scale SST variations in two adjacent but distinct reef environments at Little Cayman, Cayman Islands. Our results indicate that two massive Diploria strigosa corals growing in the lagoon and in the fore reef responded differently to past warming events. Coral Sr/Ca data from the shallow lagoon successfully record high summer temperatures confirmed by in situ observations (>33°C). Surprisingly, coral Sr/Ca from the deeper fore reef is strongly affected by thermal stress events, although seasonal temperature extremes and mean SSTs at this site are reduced compared to the lagoon. The shallow lagoon coral showed decadal variations in Sr/Ca, supposedly related to the modulation of lagoonal temperature through varying tidal water exchange, influenced by the 18.6 year lunar nodal cycle. Our results show that reef-scale SST variability can be much larger than suggested by satellite SST measurements. Thus, using coral SST proxy records from different reef zones combined with in situ observations will improve conservation programs that are developed to monitor and predict potential thermal stress on coral reefs.

Coral Calcification Across a Natural Gradient in Ocean Acidification

NASA Astrophysics Data System (ADS)

Cohen, A. L.; Brainard, R. E.; Young, C.; Shamberger, K. E.; McCorkle, D. C.; Feely, R. A.; Mcleod, E.; Cantin, N.; Rose, K.; Lohmann, G. P.

2011-12-01

Much of our understanding of the impact of ocean acidification on coral calcification comes from laboratory manipulation experiments in which corals are reared under a range of seawater pH and aragonite saturation states (μar) equivalent to those projected for the next hundred years. In general, experiments show a consistently negative impact of acidification on coral calcification, leading to predictions of mass coral reef extinctions by dissolution as natural rates of carbonate erosion exceed the rates at which corals and other reef calcifiers can replace it. The tropical oceans provide a natural laboratory within which to test hypotheses about the longer term impact and adaptive potential of corals to acidification of the reef environment. Here we report results of a study in which 3-D CT scan and imaging techniques were used to quantify annual rates of calcification by conspecifics at 12 reefs sites spanning a natural gradient in ocean acidification. In situ μar calculated from alkalinity and DIC measurements of reef seawater ranged from less than 2.7 on an eastern Pacific Reef to greater than 4.0 in the central Red Sea. No correlation between μar and calcification was observed across this range. Corals living on low μar reefs appear to be calcifying as fast, sometimes faster than conspecifics living on high μar reefs. We used total lipid and tissue thickness to index the energetic status of colonies collected at each of our study sites. Our results support the hypothesis that energetics plays a key role in the coral calcification response to ocean acidification. Indeed, the true impact of acidification on coral reefs will likely be felt as temperatures rise and the ocean becomes more stratified, depleting coral energetic reserves through bleaching and reduced nutrient delivery to oceanic reefs.

No Reef Is an Island: Integrating Coral Reef Connectivity Data into the Design of Regional-Scale Marine Protected Area Networks.

PubMed

Schill, Steven R; Raber, George T; Roberts, Jason J; Treml, Eric A; Brenner, Jorge; Halpin, Patrick N

2015-01-01

We integrated coral reef connectivity data for the Caribbean and Gulf of Mexico into a conservation decision-making framework for designing a regional scale marine protected area (MPA) network that provides insight into ecological and political contexts. We used an ocean circulation model and regional coral reef data to simulate eight spawning events from 2008-2011, applying a maximum 30-day pelagic larval duration and 20% mortality rate. Coral larval dispersal patterns were analyzed between coral reefs across jurisdictional marine zones to identify spatial relationships between larval sources and destinations within countries and territories across the region. We applied our results in Marxan, a conservation planning software tool, to identify a regional coral reef MPA network design that meets conservation goals, minimizes underlying threats, and maintains coral reef connectivity. Our results suggest that approximately 77% of coral reefs identified as having a high regional connectivity value are not included in the existing MPA network. This research is unique because we quantify and report coral larval connectivity data by marine ecoregions and Exclusive Economic Zones (EZZ) and use this information to identify gaps in the current Caribbean-wide MPA network by integrating asymmetric connectivity information in Marxan to design a regional MPA network that includes important reef network connections. The identification of important reef connectivity metrics guides the selection of priority conservation areas and supports resilience at the whole system level into the future.

No Reef Is an Island: Integrating Coral Reef Connectivity Data into the Design of Regional-Scale Marine Protected Area Networks

PubMed Central

Schill, Steven R.; Raber, George T.; Roberts, Jason J.; Treml, Eric A.; Brenner, Jorge; Halpin, Patrick N.

2015-01-01

We integrated coral reef connectivity data for the Caribbean and Gulf of Mexico into a conservation decision-making framework for designing a regional scale marine protected area (MPA) network that provides insight into ecological and political contexts. We used an ocean circulation model and regional coral reef data to simulate eight spawning events from 2008–2011, applying a maximum 30-day pelagic larval duration and 20% mortality rate. Coral larval dispersal patterns were analyzed between coral reefs across jurisdictional marine zones to identify spatial relationships between larval sources and destinations within countries and territories across the region. We applied our results in Marxan, a conservation planning software tool, to identify a regional coral reef MPA network design that meets conservation goals, minimizes underlying threats, and maintains coral reef connectivity. Our results suggest that approximately 77% of coral reefs identified as having a high regional connectivity value are not included in the existing MPA network. This research is unique because we quantify and report coral larval connectivity data by marine ecoregions and Exclusive Economic Zones (EZZ) and use this information to identify gaps in the current Caribbean-wide MPA network by integrating asymmetric connectivity information in Marxan to design a regional MPA network that includes important reef network connections. The identification of important reef connectivity metrics guides the selection of priority conservation areas and supports resilience at the whole system level into the future. PMID:26641083

75 FR 47624 - U.S. Coral Reef Task Force Public Meeting and Public Comment

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-06

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service U.S. Coral Reef Task Force Public Meeting and... (Service), announce a public meeting of the U.S. Coral Reef Task Force (USCRTF) and a request for written.... Coral Reef Task Force Department of the Interior Liaison, U.S. Department of the Interior, MS-3530-MIB...

Ocean acidification accelerates dissolution of experimental coral reef communities

NASA Astrophysics Data System (ADS)

Comeau, S.; Carpenter, R. C.; Lantz, C. A.; Edmunds, P. J.

2015-01-01

Ocean acidification (OA) poses a severe threat to tropical coral reefs, yet much of what is know about these effects comes from individual corals and algae incubated in isolation under high pCO2. Studies of similar effects on coral reef communities are scarce. To investigate the response of coral reef communities to OA, we used large outdoor flumes in which communities composed of calcified algae, corals, and sediment were combined to match the percentage cover of benthic communities in the shallow back reef of Moorea, French Polynesia. Reef communities in the flumes were exposed to ambient (~ 400 μatm) and high pCO2 (~ 1300 μatm) for 8 weeks, and calcification rates measured for the constructed communities including the sediments. Community calcification was reduced by 59% under high pCO2, with sediment dissolution explaining ~ 50% of this decrease; net calcification of corals and calcified algae remained positive but was reduced by 29% under elevated pCO2. These results show that, despite the capacity of coral reef calcifiers to maintain positive net accretion of calcium carbonate under OA conditions, reef communities might transition to net dissolution as pCO2 increases, particularly at night, due to enhanced sediment dissolution.

Ocean acidification accelerates dissolution of experimental coral reef communities

NASA Astrophysics Data System (ADS)

Comeau, S.; Carpenter, R. C.; Lantz, C. A.; Edmunds, P. J.

2014-08-01

Ocean acidification (OA) poses a severe threat to tropical coral reefs, yet much of what is know about these effects comes from individual corals and algae incubated in isolation under high pCO2. Studies of similar effects on coral reef communities are scarce. To investigate the response of coral reef communities to OA, we used large outdoor flumes in which communities composed of calcified algae, corals, and sediment were combined to match the percentage cover of benthic communities in the shallow back reef of Moorea, French Polynesia. Reef communities in the flumes were exposed to ambient (~400 μatm) and high pCO2 (~1300 μatm) for 8 weeks, and calcification rates measured for the constructed communities including the sediments. Community calcification was depressed 59% under high pCO2, with sediment dissolution explaining ~50% of this decrease; net calcification of corals and calcified algae remained positive, but was reduced 29% under elevated pCO2. These results show that despite the capacity of coral reef calcifiers to maintain positive net accretion of calcium carbonate under OA conditions, reef communities might switch to net dissolution as pCO2 increases, particularly at night, due to enhanced sediment dissolution.

Synergistic impacts of global warming on the resilience of coral reefs

PubMed Central

Bozec, Yves-Marie; Mumby, Peter J.

2015-01-01

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

Enhanced macroboring and depressed calcification drive net dissolution at high-CO2 coral reefs.

PubMed

Enochs, Ian C; Manzello, Derek P; Kolodziej, Graham; Noonan, Sam H C; Valentino, Lauren; Fabricius, Katharina E

2016-11-16

Ocean acidification (OA) impacts the physiology of diverse marine taxa; among them corals that create complex reef framework structures. Biological processes operating on coral reef frameworks remain largely unknown from naturally high-carbon-dioxide (CO 2 ) ecosystems. For the first time, we independently quantified the response of multiple functional groups instrumental in the construction and erosion of these frameworks (accretion, macroboring, microboring, and grazing) along natural OA gradients. We deployed blocks of dead coral skeleton for roughly 2 years at two reefs in Papua New Guinea, each experiencing volcanically enriched CO 2 , and employed high-resolution micro-computed tomography (micro-CT) to create three-dimensional models of changing skeletal structure. OA conditions were correlated with decreased calcification and increased macroboring, primarily by annelids, representing a group of bioeroders not previously known to respond to OA. Incubation of these blocks, using the alkalinity anomaly methodology, revealed a switch from net calcification to net dissolution at a pH of roughly 7.8, within Intergovernmental Panel on Climate Change's (IPCC) predictions for global ocean waters by the end of the century. Together these data represent the first comprehensive experimental study of bioerosion and calcification from a naturally high-CO 2 reef ecosystem, where the processes of accelerated erosion and depressed calcification have combined to alter the permanence of this essential framework habitat. © 2016 The Authors.

Enhanced macroboring and depressed calcification drive net dissolution at high-CO2 coral reefs

PubMed Central

Manzello, Derek P.; Kolodziej, Graham; Noonan, Sam H. C.; Valentino, Lauren; Fabricius, Katharina E.

2016-01-01

Ocean acidification (OA) impacts the physiology of diverse marine taxa; among them corals that create complex reef framework structures. Biological processes operating on coral reef frameworks remain largely unknown from naturally high-carbon-dioxide (CO2) ecosystems. For the first time, we independently quantified the response of multiple functional groups instrumental in the construction and erosion of these frameworks (accretion, macroboring, microboring, and grazing) along natural OA gradients. We deployed blocks of dead coral skeleton for roughly 2 years at two reefs in Papua New Guinea, each experiencing volcanically enriched CO2, and employed high-resolution micro-computed tomography (micro-CT) to create three-dimensional models of changing skeletal structure. OA conditions were correlated with decreased calcification and increased macroboring, primarily by annelids, representing a group of bioeroders not previously known to respond to OA. Incubation of these blocks, using the alkalinity anomaly methodology, revealed a switch from net calcification to net dissolution at a pH of roughly 7.8, within Intergovernmental Panel on Climate Change's (IPCC) predictions for global ocean waters by the end of the century. Together these data represent the first comprehensive experimental study of bioerosion and calcification from a naturally high-CO2 reef ecosystem, where the processes of accelerated erosion and depressed calcification have combined to alter the permanence of this essential framework habitat. PMID:27852802

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

Benthic habitat map of U.S. Coral Reef Task Force Faga‘alu Bay priority study area, Tutuila, American Samoa

USGS Publications Warehouse

Cochran, Susan A.; Gibbs, Ann E.; D'Antonio, Nicole L.; Storlazzi, Curt D.

2016-05-18

The coral reef in Faga‘alu Bay, Tutuila, American Samoa, has suffered numerous natural and anthropogenic stresses. Areas once dominated by live coral are now mostly rubble surfaces covered with turf or macroalgae. In an effort to improve the health and resilience of the coral reef system, the U.S. Coral Reef Task Force selected Faga‘alu Bay as a priority study area. To support these efforts, the U.S. Geological Survey mapped nearly 1 km2 of seafloor to depths of about 60 m. Unconsolidated sediment (predominantly sand) constitutes slightly greater than 50 percent of the seafloor in the mapped area; reef and other hardbottom potentially available for coral recruitment constitute nearly 50 percent of the mapped area. Of this potentially available hardbottom, only slightly greater than 37 percent is covered with at least 10 percent coral, which is fairly evenly distributed between the reef flat, fore reef, and offshore bank/shelf. 

Vulnerability of Coral Reefs to Bioerosion From Land-Based Sources of Pollution

NASA Astrophysics Data System (ADS)

Prouty, Nancy G.; Cohen, Anne; Yates, Kimberly K.; Storlazzi, Curt D.; Swarzenski, Peter W.; White, Darla

2017-12-01

Ocean acidification (OA), the gradual decline in ocean pH and [CO32-] caused by rising levels of atmospheric CO2, poses a significant threat to coral reef ecosystems, depressing rates of calcium carbonate (CaCO3) production, and enhancing rates of bioerosion and dissolution. As ocean pH and [CO32-] decline globally, there is increasing emphasis on managing local stressors that can exacerbate the vulnerability of coral reefs to the effects of OA. We show that sustained, nutrient rich, lower pH submarine groundwater discharging onto nearshore coral reefs off west Maui lowers the pH of seawater and exposes corals to nitrate concentrations 50 times higher than ambient. Rates of coral calcification are substantially decreased, and rates of bioerosion are orders of magnitude higher than those observed in coral cores collected in the Pacific under equivalent low pH conditions but living in oligotrophic waters. Heavier coral nitrogen isotope (δ15N) values pinpoint not only site-specific eutrophication, but also a sewage nitrogen source enriched in 15N. Our results show that eutrophication of reef seawater by land-based sources of pollution can magnify the effects of OA through nutrient driven-bioerosion. These conditions could contribute to the collapse of coastal coral reef ecosystems sooner than current projections predict based only on ocean acidification.