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Abstracts: 2008 International Coral Reef Symposium
- A Strategic Approach For Developing A National Baseline Coral Reef Condition
- Solar Radiation Dosimetry in Florida Coral Reefs Determined from Remote Sensed, Modeled, and In Situ Data
- Development and Implementation of Coral Reef Biocriteria in U.S. Jurisdictions
- Estimating Three-Dimensional Coral Colony Surface Area from Simple Field Measurements
- Water Quality Standards For Coral Reef Protection
- Patterns of Coral Diseases in the Florida Keys from 1998 – 2005
- Responses Of Coral Communities in The Florida Keys Following Multiple Stressor Events in 1997-1998
- Species Specific Responses To Experimental Bleaching Of Corals
A Strategic Approach For Developing A National Baseline Coral Reef Condition
Patricia BRADLEY1, Wayne DAVIS*2, William FISHER3, Michael MCDONALD4 1Office of Research and Development (ORD)/NHEERL/AED, U.S. EPA, Key West, FL, 2Office of Environmental Information, U.S. EPA, Ft. Meade, MD, 3Office of Research and Development/NHEERL/GED, U.S. EPA, Gulf Breeze, FL, 4Office of Research and Development/NHEERL, U.S. EPA, Research Triangle Park, NC
The U.S. Congress, American public, and other interested parties want to know the condition of U.S. and territorial coral reef ecosystems. They want to know whether the reefs’ conditions are getting better or worse, and whether our programs and policies are making a difference. Many organizations monitor coral reefs, but these efforts generally operate independently of one another, have many different missions and mandates, and are fairly localized. There is a critical need for nationally-consistent, comprehensive, and scientifically-defensible monitoring to detect environmental status and trends for coral reef ecosystems.
We propose to apply the approach developed by the U.S. Environmental Protection Agency’s Environmental Monitoring and Assessment Program (EMAP): development of unbiased statistical design frameworks, and sensitive ecological indicators that are responsive to a gradient of stressors. This approach has been successfully applied for freshwater, estuarine and forest ecosystems and is transferable to assess coral reef ecosystems at state, regional, and national scales. Developing and maintaining such a coral reef monitoring program requires a partnership among the various federal, state and territorial agencies with responsibilities for coral reefs.
Our first application of this approach is in the U.S. Virgin Islands (USVI). In 2006, indicators were evaluated across stressor gradients using EPA’s recently published Stony Coral Rapid Bioassessment Protocol. In 2007, a probabilistic sample design was used to monitor the coral reefs around St. Croix, USVI and a similar design will be used for St. John and St. Thomas, USVI in 2008. These results, coupled with those of other agencies and organizations will provide valid indicators and data for EPA’s “Report on the Environment” and begin to address the current condition of the Nation’s coral reef ecosystems and the impacts of human activities upon them.
Solar Radiation Dosimetry in Florida Coral Reefs Determined from Remote Sensed, Modeled, and In Situ Data
Mace BARRON*1, Deborah VIVIAN1, Susan YEE1, Debbie SANTAVY1 1U.S. Environmental Protection Agency, Gulf Ecology Division, Gulf Breeze, FL
Solar irradiance has been increasingly recognized as an important determinant of bleaching in coral reefs, but measurements of solar radiation exposure within coral reefs have been relatively limited. Solar radiation dosimetry within multiple coral reef areas of South Florida was assessed using remote sensed, modeled, and measured values during a minor bleaching event (August 2005).
Coral reefs in the Dry Tortugas and Upper Keys had similar diffuse down welling attenuation coefficients (Kd, m-1), but Kd values were significantly greater in the Middle and Lower Keys. Mean one percent attenuation depths varied by reef region for ultraviolet B (UVB; 9.7 to 20 m), ultraviolet A (UVA; 22 to 40 m) and visible (27 to 43 m) solar radiation. Solar irradiances determined from remote sensed surface intensity and Kd were significantly correlated with measured values, but were generally over estimated at the depth of corals. Solar irradiances modeled using an atmospheric radiative transfer model parameterized with site specific approximations of cloud cover showed close agreement with measured values.
Estimated daily doses (W*hr/m2) of UVB (0.01-19), UVA (2- 360) and visible (29-1653) solar radiation varied with coral depth (2 to 24 m) and meteorological conditions. These results indicate large variation in solar radiation dosimetry within coral reefs that may be estimated with reasonable accuracy using regional Kd measurements and radiative transfer modeling.
Development and Implementation of Coral Reef Biocriteria in U.S. Jurisdictions
Patricia BRADLEY*1, Wayne DAVIS2, William FISHER3, Bell HEIDI4, Valerie CHAN5, Buddy LOBUE6, Wendy WILTSE7 1Office of Research and Development/NHEERL/AED, U.S. EPA, Key West, FL, 2Office of Environmental Information, U.S. EPA, Ft. Meade, MD, 3Office of Research and Development/NHEERL/GED, U.S. EPA, Gulf Breeze, FL, 4Office of Water, U.S. EPA, Washington, DC, 5Office of Research and Development/OSP, U.S. EPA, Washington, DC, 6Region 2, U.S. EPA, New York, NY, 7Region 9, U.S. EPA, Honolulu, HI
U.S. coral reef ecosystems are threatened by a variety of anthropogenic activities (e.g., pollution, over fishing, vessel groundings, excess nutrients, coastal development, etc.), natural stressors (e.g., tropical storms), and natural stressors that have been exacerbated by anthropogenic activities (e.g., climate change).
Biological communities are dependable indicators of the health of aquatic ecosystems because they are responsive to effects of low-level, chronic, and non-point source pollution, and to interactive stressors not captured by physical and chemical water quality standards. Under the Clean Water Act, states may adopt water quality criteria based on biological, physical, and chemical criteria.
The President’s Ocean Action Plan directs the U.S. Environmental Protection Agency (EPA) to develop biological assessment methods and biological criteria for evaluating the health of coral reefs and associated water quality. Biocriteria are narrative descriptions or numeric values representing the biological condition of biological communities. Rigorous biological assessments are needed to identify metrics for a monitoring program and to set expectations for the water body. These are used to develop a scoring system to indicate the health of the water body and to develop biocriteria for each class or designated use.
EPA is fostering development of coral reef biocriteria through focused research, evaluation, and collaboration with U.S. states and territories. To date, EPA has produced and validated a Stony Coral Rapid Bioassessment Protocol for application on EPA’s biocriteria and a coral reef bioindicators web site (72 pp, 4.9 MB, About PDF) for dissemination of information.
EPA and the collaborating states and territories have a wide variety of ongoing activities to conduct systematic coral bioassessments, develop metrics, design monitoring programs, and work toward adoption of protective and defensible biocriteria.
Estimating Three-Dimensional Coral Colony Surface Area from Simple Field Measurements
Lee COURTNEY1, William FISHER*1, Sandy RAIMONDO1, Leah OLIVER1, William DAVIS1 1National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, US Environmental Protection Agency, Gulf Breeze, FL
Topographic surface area (SA) of coral colonies is a critical descriptor for biological and physical attributes of reef-building (scleractinian) corals. SA is directly related to coral sustainability (e.g., living tissue) and anthropocentric values (e.g., fish habitat, shoreline protection). Most existing methods to estimate colony SA are destructive and limited to laboratory settings. However, a recently-described photographic method was tested and found applicable to field colonies. A highly accurate 3- dimensional digital reconstruction is generated using specialized computer software and multiple images of a coral colony. SA determined from the reconstructed colony is within 2-5% of SA determined by laser-scanning. The method was used to evaluate three approaches, or models, for calculating SA of coral colonies from simple morphological measurements made in the field. The models included a volumetric size-class (SA = 5 sides of a cube), a hemispheric surrogate (SA = 2πr2, where r is determined from height, diameter and width), and a suite of log-linear formulae generated from stepwise multiple regression of reconstructed colony SA against colony height, diameter and width. When SA determined using field collected data were compared to SA of reconstructed images, the log-linear model was most accurate (12% difference from reconstruction values), followed by the hemispheric surrogate (17% difference) and size-classes (40% difference). While only four species were included in these analyses (Montastraea faveolata, M. cavernosa, Diploria strigosa and D. clivosa), SA of specimens from seven additional species were credibly estimated (<20% difference) using the log-linear and hemispheric models. Greater differences were observed with more complex colonies which may require different models. Results from this study have been used in the Environmental Protection Agency’s Stony Coral Rapid Bioassessment Protocol to support indicators of coral reef value and sustainability.
Water Quality Standards For Coral Reef Protection
William FISHER*1, Aaron HUTCHINS2, Leska FORE3, Wayne DAVIS4, Charles LOBUE5, Heidi BELL6 1Office of Research and Development, U.S. Environmental Protection Agency, Gulf Breeze, FL, 2Department of Planning and Natural Resources, U.S. Virgin Islands, Frederiksted, United States Minor Outlying Islands, 3Statistical Design, Seattle, WA, 4Office of Environmental Information, U.S. Environmental Protection Agency, Ft. Meade, MD, 5Region 2, U.S. Environmental Protection Agency, New York, NY, 6Office of Water, Office of Science and Technology, U.S. Environmental Protection Agency, Washington, D.C., DC
Resource managers have few tools to counteract the growing impacts of human coastal and watershed activities on coral reefs. Water quality standards for coral reef protection—including biological criteria (biocriteria)—have enormous potential but are not currently used by any U.S. jurisdiction.
The Environmental Protection Agency is promoting coral reef biocriteria through collaborative development of bioassessment procedures and monitoring strategies suitable for regulatory activities. A rapid bioassessment protocol (RBP) for reefbuilding stony corals (Scleractinia) was developed and tested as an initial step. Scleractinia were selected because much of the ecological and economic value of coral reefs is directly attributable to the physical structure of stony corals. The RBP requires only three underwater observations but provides both colony and surface area characteristics and incorporates a three-dimensional approach to document colony size (indicator of ecosystem services) and the amount of live tissue (coral capacity for growth and reproduction). Preliminary testing in the Florida Keys showed that information gained through the RBP had relevance to coral reef management and sufficient precision to distinguish spatial and temporal differences. Further validation was completed in the U.S. Virgin Islands, where corals were sampled across human disturbance gradients to determine which indicators were responsive to anthropogenic stress, a requirement for regulatory enforcement. Several RBP indicators, including taxa richness, colony size, total and live surface area were found to be positively correlated with distance from human activity. These indicators also had sufficient precision to be effective in most monitoring programs, and are now considered strong candidates for application in a regulatory context. Implementation of enforceable biocriteria will depend on the application of responsive metrics in a defensible long-term monitoring program. Once established, such a program will provide valuable, long-term records of coral condition and regulatory compliance.
Patterns of Coral Diseases in the Florida Keys from 1998 – 2005
Deborah SANTAVY*1, Susan YEE1, Mace BARRON1 1Gulf Ecology Division, US EPA, NHEERL, Gulf Breeze, FL
Diseases have been identified as a major threat to reef-building corals causing morbidity and mortality. Increased mortality has lead to degradation, especially those reefs dominated by several susceptible species. Increased morbidity has reduced the health of reef-building corals making them more vulnerable to other environmental stressors. Reported incidence, prevalence, and distribution of coral diseases have been greatest from the tropical Western Atlantic, with emergent coral diseases, such as aspergillosis and serratiosis originating from terrestrial sources. Epizootiological studies assessed the prevalence of dominant coral diseases in the Florida Keys reef tract from 1998-2005, from the Dry Tortugas to the Upper Keys. Annual assessments were repeated at permanent sites in mid-summer throughout the area. Data were adjusted so coral community composition, specifically the absence of susceptible species, did not bias the results. Canonical correspondence analyses revealed coral diseases patterns related to spatial and temporal parameters. Reef depth was the most discriminating parameter for all coral diseases surveyed. White plague and white-band disease had the highest prevalence on deeper reefs, whereas black-band disease was most prevalent on mid-depth reefs, and red-band disease and white pox were most prevalent on shallow reefs. White-band disease had the highest prevalence in the early years, whereas dark-spots disease had increased incidence in the later years of the study. Dark-spots and yellow-blotch diseases were more common in the Dry Tortugas, whereas black-band disease had the highest prevalence in the Middle Keys. One of the first steps in identifying and managing health threats of reefs is to establish disease prevalence and incidence to understand patterns and associate them with other variables to determine causative factors. In tropical marine systems prevention or control of coral disease can assist in precluding the collapse of important ecological functions and ecosystem services.
Responses Of Coral Communities in The Florida Keys Following Multiple Stressor Events in 1997-1998
Deborah SANTAVY*1, Erich MUELLER2, Lauri MACLAUGHLIN3, Esther PETERS4, Robert QUARLES1, Mace BARRON1 1US EPA, NHEERL, Gulf Ecology Division, Gulf Breeze, FL, 2Perry Institute for Marine Science, Jupiter, FL, 3NOAA, Florida Keys National Marine Sanctuary, Key Largo, FL, 4Tetra Tech. Inc., Fairfax, VA Coral reefs in South Florida have declined over the past 40 years and are projected to continue to deteriorate due to persistent and intermittent exposure to multiple chronic stressors. This study compared changes in the condition of mature colonies (≥ 10 cm) in two regions of South Florida from 1998-2002, following exposure to several large scale disturbances including Hurricane Georges and massive coral bleaching. Coral abundance, diversity measures, disease, and bleaching prevalence on reefs near the remote off-shore islands of the Dry Tortugas were compared to reefs near Key West characterized by higher population density and greater anthropogenic influences. Initially in the spring of 1998, Key West and Dry Tortugas reefs were similar in abundance, species richness, evenness, diversity, dominance, and prevalence of disease at the locations sampled. Prevalence of coral bleaching and disease significantly increased on reefs in both regions during the 1998 summer El Niño event, with Key West reefs exhibiting the greatest prevalence and severity of coral bleaching and disease. Coral abundance significantly decreased in 1998 in both regions, but remained lower only at Key West reefs during the study. The greatest reef degradation occurred after increased sea temperatures led to elevated coral bleaching and disease prior to Hurricane Georges. Acroporids declined near Key West from 45 colonies/site (spring 1998) to ≤4 colonies (2002), whereas Dry Tortugas acroporids initially declined but recovered within 5 years. Key West reefs presumptively lost critical community properties such as regenerative capacity provided by the affected species, as indicated by their inability to recover or return to original conditions. In contrast, Dry Tortugas reefs resisted major changes and maintained coral community properties necessary to persist and regenerate in the presence of similar disturbances.
Species Specific Responses To Experimental Bleaching Of Corals
Deborah VIVIAN*1, Susan YEE1, Sarah KELL1, Cheryl MCGILL1, Mace BARRON1 1Gulf Ecology Division, US EPA, Gulf Breeze, FL The combined effects of temperature and solar radiation on six species of reef-building corals were examined using a laboratory coral exposure system. Diploria clivosa, Montastraea faveolata, Siderastrea siderea, Siderastrea radians, Stephanocoenia intersepts, and Porites astreoides were first exposed for 10 days to two temperatures (26 or 31oC) and three solar radiation doses (ultraviolet radiation (UVA) at 13.7, 68, and 84 W•d/m2). Corals were then monitored for a 40 day recovery period. A pulse amplitude modulation (PAM) fluorometer was used to monitor changes in photosystem II efficiency (ΔFv/Fm) during the exposure period. Weekly observations and PAM measurements were conducted during the recovery period to assess changes in bleaching and health. After recovery, pigment, zooxanthellae, and protein concentrations were analyzed to determine recovery rates of corals. During initial exposure, species responded differently to the combined effects of temperature and solar radiation with P. astreoides showing the greatest decline in Fv/Fm over time and S. siderea showing the least change in Fv/Fm. Most species responded similarly to temperature showing a decrease in Fv/Fm in the 31oC treatments. However, species response to light was significantly different (p = 0.038), with S. intersepts showing the greatest response to high radiation and S. siderea the weakest. Highest mortalities were observed in S. intersepts and M. faveolata (22%) exposed to the highest solar radiation at the end of exposure. Changes in Fv/Fm showed poor recovery for only S. intersepts and M. faveolata exposed to high solar radiation. Recovery rates based on pigment, zooxanthellae, and protein concentrations were variable among species and treatments. Responses to combined effects of solar radiation and temperature are species specific for both experimental bleaching and recovery.
Quantifying Environmental Influences On Coral Bleaching in The Florida Keys Using Multi-Species Models Susan YEE*1, Deborah SANTAVY1, Mace BARRON1 1ORD/NHEERL/Gulf Ecology Division, U.S. E.P.A., Gulf Breeze, FL Differential susceptibility among reef-building coral species to temperature-induced mass bleaching events can lead to community shifts and loss of diversity. We evaluated environmental influences on coral colony bleaching from 1998-2005 in the Florida Keys, USA. We used clustered binomial regression to develop models incorporating species-specific responses to the environment in order to identify conditions and species for which bleaching is likely to be severe. We evaluated three separate models incorporating environment, species composition, and species-specific responses to environment, and showed observed prevalence of bleaching reflects an interaction between species composition and local environmental conditions. Environmental variables, including elevated sea temperature (Degree Heating Weeks), solar radiation, and reef depth, explained much of the variability in colony bleaching across space and time. The effects of environmental variables could only partially be explained by corresponding differences in species composition. Species-specific models indicated individual coral species responded differently to local environmental conditions and had different sensitivities to temperature-induced bleaching. Acropora palmata experienced the severest response to temperature, whereas for other taxa the response was fairly weak. For many coral species, including Colpophyllia natans, Dichocoenia stokesii, Diploria strigosa, Montastraea annularis, M. cavernosa, and Siderastrea siderea, bleaching was exacerbated by high solar radiation. A reduced probability of bleaching in shallow locations for S. siderea may reflect an ability to acclimatize to local conditions. Model development provides a useful tool for quantifying the influence of the local environment on species-specific bleaching sensitivities, identifying susceptible species, and predicting the likelihood of mass bleaching events with changing environmental conditions.