940 resultados para Modern coral reefs


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ReefBase a global database of coral reefs systems and their resources was initiated at International Center for Living Aquatic Resources Management (ICLARM), Philippines in November 1993. The CEC has provided funding for the first two years and the database was developed in collaboration with the World Conservation Monitoring Centre in Cambridge, UK, as well as other national, regional, and international institutions. The ReefBase project activities and what ICLARM will do to accomplish the project objectives are briefly discussed.

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Coral bleaching and subsequent mortality represent a major threat to the future health and productivity of coral reefs. However a lack of reliable data on occurrence, severity and other characteristics of bleaching events hampers research on the causes and consequences of this important phenomenon. This article describes a global protocol for monitoring coral bleaching events, which addresses this problem and can be used by people with different levels of expertise and resources.

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The Global Coral Reef Monitoring Network (GCRMN) is an operational unit of the International Coral Reef Initiative (ICRI), established in 1995 and maintained by the Australian Institute of Marine Science (AIMS). The main responsibilities are to provide data and information on the global status of coral reefs, assess how people use and interact with reefs, assist coral reef management, and raise awareness among all stakeholders of the status of reefs and the need for urgent action. It is represented by 17 regional nodes, with overall coordination by a global coordinator based at AIMS.

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This Freely Associated States Shallow-water Coral Ecosystem Mapping Implementation Plan (FAS MIP) presents a framework for the development of shallow-water (~0–40 m; 0–22 fm) benthic habitat and possibly bathymetric maps of critical areas of the Freely Associated States (FAS). The FAS is made up of three self-governing groups of islands and atolls—the Republic of Palau (Palau), the Federated States of Micronesia (FSM), and the Republic of the Marshall Islands (RMI)—that are affiliated with the United States through Compacts of Free Association. This MIP was developed with extensive input from colleges, national and state regulatory and management agencies, federal agencies, non-governmental organizations, and individuals involved in or supporting the conservation and management of the FAS’s coral ecosystems. A list of organizations and individuals that provided input to the development of this MIP is provided in Appendix 1. This MIP has been developed to complement the Coral Reef Mapping Implementation Plan (2nd Draft) released in 1999 by the U.S. Coral Reef Task Force’s Mapping and Information Synthesis Working Group. That plan focused on mapping United States and FAS shallow-water (then defined as <30 m) coral reefs by 2009, based on available funding and geographic priorities, using primarily visual interpretation of aerial photography and satellite imagery. This MIP focuses on mapping the shallow-water (now defined as 0–40 m, rather than 0–30 m) coral ecosystems of the FAS using a suite of technologies and map development procedures. Both this FAS MIP and the 1999 Coral Reef Mapping Implementation Plan (2nd Draft) support to goals of the National Action Plan to Conserve Coral Reefs (U.S. Coral Reef Task Force, 2000). This FAS MIP presents a framework for mapping the coral ecosystems of the FAS and should be considered an evolving document. As priorities change, funding opportunities arise, new data are collected, and new technologies become available, the information presented herein will change.

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Coral bleaching is a significant contributor to the worldwide degradation of coral reefs and is indicative of the termination of symbiosis between the coral host and its symbiotic algae (dinoflagellate; Symbiodinium sp. complex), usually by expulsion or xenophagy (symbiophagy) of its dinoflagellates. Herein, we provide evidence that during the earliest stages of environmentally induced bleaching, heat stress and light stress generate distinctly different pathomorphological changes in the chloroplasts, while a combined heat- and light-stress exposure induces both pathomorphologies; suggesting that these stressors act on the dinoflagellate by different mechanisms. Within the first 48 hours of a heat stress (32°C) under low-light conditions, heat stress induced decomposition of thylakoid structures before observation of extensive oxidative damage; thus it is the disorganization of the thylakoids that creates the conditions allowing photo-oxidative-stress. Conversely, during the first 48 hours of a light stress (2007 µmoles m−2 s−1 PAR) at 25°C, condensation or fusion of multiple thylakoid lamellae occurred coincidently with levels of oxidative damage products, implying that photo-oxidative stress causes the structural membrane damage within the chloroplasts. Exposure to combined heat- and light-stresses induced both pathomorphologies, confirming that these stressors acted on the dinoflagellate via different mechanisms. Within 72 hours of exposure to heat and/or light stresses, homeostatic processes (e.g., heat-shock protein and anti-oxidant enzyme response) were evident in the remaining intact dinoflagellates, regardless of the initiating stressor. Understanding the sequence of events during bleaching when triggered by different environmental stressors is important for predicting both severity and consequences of coral bleaching

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Since 1999, NOAA’s Center for Coastal Monitoring and Assessment, Biogeography Branch (CCMA-BB) has been working with federal and territorial partners to characterize monitor and assess the status of the marine environment in southwestern Puerto Rico. This effort is part of the broader NOAA Coral Reef Conservation Program’s (CRCP) National Coral Reef Ecosystem Monitoring Program (NCREMP). With support from CRCP’s NCREMP, CCMA conducts the “Caribbean Coral Reef Ecosystem Monitoring project” (CREM) with goals to: (1) spatially characterize and monitor the distribution, abundance and size of marine fauna associated with shallow water coral reef seascapes (mosaics of coral reefs, seagrasses, sand and mangroves); (2) relate this information to in situ fine-scale habitat data and the spatial distribution and diversity of habitat types using benthic habitat maps; (3) use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting; (4) establish the efficacy of those management decisions; and (5) develop data collection and data management protocols. The monitoring effort of the La Parguera region in southwestern Puerto Rico was conducted through partnerships with the University of Puerto Rico (UPR) and the Puerto Rico Department of Natural and Environmental Resources (DNER). Project funding was primarily provided by NOAA CRCP and CCMA. In recent decades, scientific and non-scientific observations have indicated that the structure and function of the coral reef ecosystem in the La Parguera region have been adversely impacted by a wide range of environmental stressors. The major stressors have included the mass Diadema die off in the early 1980s, a suite of hurricanes, overfishing, mass mortality of Acropora corals due to disease and several coral bleaching events, with the most severe mass bleaching episode in 2005. The area is also an important recreational resource supporting boating, snorkeling, diving and other water based activities. With so many potential threats to the marine ecosystem several activities are underway or have been implemented to manage the marine resources. These efforts have been supported by the CREM project by identifying marine fauna and their spatial distributions and temporal dynamics. This provides ecologically meaningful data to assess ecosystem condition, support decision making in spatial planning (including the evaluation of efficacy of current management strategies) and determine future information needs. The ultimate goal of the work is to better understand the coral reef ecosystems and to provide information toward protecting and enhancing coral reef ecosystems for the benefit of the system itself and to sustain the many goods and services that it offers society. This Technical Memorandum contains analysis of the first seven years of fish survey data (2001-2007) and associated characterization of the benthos. The primary objectives were to quantify changes in fish species and assemblage diversity, abundance, biomass and size structure and to provide spatially explicit information on the distribution of key species or groups of species and to compare community structure across the seascape including fringing mangroves, inner, middle, and outer reef areas, and open ocean shelf bank areas.

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The United States Coral Reef Task Force (USCRTF) was established in 1998 by Presidential Executive Order 13089 to lead U.S. efforts to preserve and protect coral reef ecosystems. Current, accurate, and consistent maps greatly enhance efforts to preserve and manage coral reef ecosystems. With comprehensive maps and habitat assessments, coral reef managers can be more effective in designing and implementing a variety of conservation measures, including: • Long-term monitoring programs with accurate baselines from which to track changes; • Place-based conservation measures such as marine protected areas (MPAs); and • Targeted research to better understand the oceanographic and ecological processes affecting coral reef ecosystem health. The National Oceanic and Atmospheric Administration’s (NOAA) National Ocean Service (NOS) is tasked with leading the coral ecosystem mapping element of the U.S. Coral Reef Task Force (CRTF) under the authority of the Presidential Executive Order 13089 to map and manage the coral reefs of the United States.

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Shallow coral reefs in the IndoPacific contain the highest diversity of marine organisms in the world, with approximately 1500 described species of fish, over 500 species of scleractinian corals, and an estimated 1-10 million organisms yet to be characterized (Reaka-Kudla et al. 1994). These centers of marine biodiversity are facing significant, multiple threats to reef community and habitat structure and function, resulting in local to wide-scale regional damage. Wilkinson (2004) characterized the major pressures as including (1) global climate change, (2) diseases, plagues and invasive species, (3) direct human pressures, (4) poor governance and lack of political will, and (5) international action or inaction. Signs that the natural plasticity of reef ecosystems has been exceeded in many areas from the effects of environmental (e.g., global climate change) and anthropogenic (e.g., land use, pollution) stressors is evidenced by the loss of 20% of the world’s coral reefs (Wilkinson 2004). Predictions are that another 24% (Wilkinson 2006) are under imminent risk of collapse and an additional 26% are under a longer term threat from reduced fitness, disease outbreaks, and increased mortality. These predictions indicate that the current list of approximately 30-40 fatal diseases impacting corals will expand as will the frequency and extent of “coral bleaching” (Waddell 2005; Wilkinson 2004). Disease and corallivore outbreaks, in combination with multiple, concomitant human disturbances are compromising corals and coral reef communities to the point where their ability to rebound from natural disturbances is being lost.

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The Flower Garden Banks National Marine Sanctuary (FGBNMS) is located in the northwestern Gulf of Mexico approximately 180 km south of Galveston, Texas. The sanctuary’s distance from shore combined with its depth (the coral caps reach to within approximately 17 m of the surface) result in limited exposure of this coral reef ecosystem to natural and human-induced impacts compared to other coral reefs of the western Atlantic. In spite of this, the sanctuary still confronts serious impacts including hurricanes events, recent outbreaks of coral disease, an increase in the frequency of coral bleaching and the massive Diadema antillarum die-off during the mid-1980s. Anthropogenic impacts include large vessel anchoring, commercial and recreational fishing, recreational scuba diving, and oil and gas related activities. The FGBNMS was designated in 1992 to help protect against some of these impacts. Basic monitoring and research efforts have been conducted on the banks since the 1970s. Early on, these efforts focused primarily on describing the benthic communities (corals, sponges) and providing qualitative characterizations of the fish community. Subsequently, more quantitative work has been conducted; however, it has been limited in spatial scope. To complement these efforts, the current study addresses the following two goals put forth by sanctuary management: 1) to develop a sampling design for monitoring benthic fish communities across the coral caps; and 2) to obtain a spatial and quantitative characterization of those communities and their associated habitats.

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Few studies have quantified the extent of nocturnal cross-habitat movements for fish, or the influence of habitat adjacencies on nutrient flows and trophodynamics. To investigate the patterns of nocturnal cross-boundary movements of fish and quantify trophic connectivity, fish were sampled at night with gillnets set along the boundaries between dominant habitat types (coral reef/seagrass and mangrove/seagrass) in southwestern Puerto Rico. Fish movement across adjacent boundary patches were equivalent at both coral reefs and mangroves. Prey biomass transfer was greater from seagrass to coral reefs (0.016 kg/km) and from mangroves to seagrass (0.006 kg/km) but not statistically significant, indicating a balance of flow between adjacent habitats. Pelagic species (jacks, sharks, rays) accounted for 37% of prey biomass transport at coral reef/seagrass and 46% at mangrove/seagrass while grunts and snappers accounted for 7% and 15%, respectively. This study indicated that coral reefs and mangroves serve as a feeding area for a wide range of multi-habitat fish species. Crabs were the most frequent prey item in fish leaving coral reefs while molluscs were observed slightly more frequently than crabs in fish entering coral reefs. For most prey types, biomass exported from mangroves was greater than biomass imported. The information on direction of fish movement together with analysis of prey data provided strong evidence of ecological linkages between distinct adjacent habitat types and highlighted the need for greater inclusion of a mosaic of multiple habitats when attempting to understand ecosystem function including the spatial transfer of energy across the seascape.

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Coral reefs throughout their circumtropical range are declining at an accelerating rate. Recent predictions indicate that 20% of the world’s reefs have been degraded, another 24% are under imminent risk of collapse, and if current estimates hold, by 2030, 26% of the world’s reefs will be lost (Wilkinson 2004). Recent changes to these ecosystems have included losses of apex predators, reductions of important herbivorous fishes and invertebrates, and precipitous declines in living coral cover, with many reefs now dominated by macroalgae. Causes have been described in broad sweeping terms: global climate change, over-fishing and destructive fishing, land-based sources of pollution, sedimentation, hurricanes, mass bleaching events and disease. Recognition that corals can succumb to disease was first reported in the early 1970’s. Then it was a unique observation, with relatively few isolated reports until the mid 1990’s. Today disease has spread to over 150 species of coral, reported from 65 countries throughout all of the world’s tropical oceans (WCMC Global Coral Disease Database). While disease continues to increase in frequency and distribution throughout the world, definitive causes of coral diseases have remained elusive for the most part, with reef managers not sufficiently armed to combat it.

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In the past decade, increased awareness regarding the declining condition of U.S. coral reefs has prompted various actions by governmental and non-governmental organizations. Presidential Executive Order 13089 created the U.S. Coral Reef Task Force (USCRTF) in 1998 to coordinate federal and state/territorial activities (Clinton, 1998), and the Coral Reef Conservation Act of 2000 provided Congressional funding for activities to conserve these important ecosystems, including mapping, monitoring and assessment projects carried out through the support of NOAA’s CRCP. Numerous collaborations forged among federal agencies and state, local, non-governmental, academic and private partners now support a variety of monitoring activities. This report shares the results of many of these monitoring activities, relying heavily on quantitative, spatially-explicit data that has been collected in the recent past and comparisons with historical data where possible. The success of this effort can be attributed to the dedication of over 270 report contributors who comprised the expert writing teams in the jurisdictions and contributed to the National Level Activities and National Summary chapters. The scope and content of this report are the result of their dedication to this considerable collaborative effort. Ultimately, the goal of this report is to answer the difficult but vital question: what is the condition of U.S. coral reef ecosystems? The report attempts to base a response on the best available science emerging from coral reef ecosystem monitoring programs in 15 jurisdictions across the country. However, few monitoring programs have been in place for longer than a decade, and many have been initiated only within the past two to five years. A few jurisdictions are just beginning to implement monitoring programs and face challenges stemming from a lack of basic habitat maps and other ecosystem data in addition to adequate training, capacity building, and technical support. There is also a general paucity of historical data describing the condition of ecosystem resources before major human impacts occurred, which limits any attempt to present the current conditions within an historical context and contributes to the phenomenon of shifting baselines (Jackson, 1997; Jackson et al., 2001; Pandolfi et al., 2005).

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This chapter covers coral reef areas under the jurisdiction of the USA in the Wider Caribbean: Florida; Flower Garden Banks; Puerto Rico; U.S. Virgin Islands; and Navassa. The following information is condensed from six chapters of The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States: 2008. Access to the full text of this comprehensive report is available at: http://ccma.nos.noaa.gov/stateofthereefs.

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Spatial variation in demographic parameters of the red throat emperor (Lethrinus miniatus) was examined among 12 coral reefs in three geographic regions (Townsville, Mackay, and Storm Cay) spanning over 3° of latitude of the Great Barrier Reef, Australia. Estimates of demographic parameters were based on age estimates from counts of annuli in whole otoliths because there was no significant difference in age estimates between whole and sectioned otoliths. There were significant regional differences in age structures, rates of somatic and otolith growth, and total mortality. The Townsville region was characterized by the greatest proportion of older fish, the smallest maximum size, and the lowest rates of otolith growth and total mortality. In contrast the Mackay region was characterized by the highest proportion of younger fish, the largest maximum size, and the highest rates of otolith growth and total mortality. Demographic parameters for the Storm Cay region were intermediate between the other two regions. Historic differences in fishing pressure and regional differences in productivity are two alternative hypotheses given to explain the regional patterns in demographic parameters. All demographic parameters were similar among the four reefs within each region. Thus, subpopulations with relatively homogeneous demographic parameters occurred on scales of reef clusters. Previous studies, by contrast, have found substantial between-reef variation in demographic parameters within regions. Thus spatial variation in demographic parameters for L. miniatus may differ from what is assumed typical for a coral-reef fish metapopulation.