http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0009264

1 School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand, 2 Hawaii Institute of Marine Biology, Kaneohe, Hawaii, United States of America

Abstract 

Diseases often display complex and distinct associations with their environment due to differences in etiology, modes of transmission between hosts, and the shifting balance between pathogen virulence and host resistance. Statistical modeling has been underutilized in coral disease research to explore the spatial patterns that result from this triad of interactions. We tested the hypotheses that: 1) coral diseases show distinct associations with multiple environmental factors, 2) incorporating interactions (synergistic collinearities) among environmental variables is important when predicting coral disease spatial patterns, and 3) modeling overall coral disease prevalence (the prevalence of multiple diseases as a single proportion value) will increase predictive error relative to modeling the same diseases independently. Four coral diseases: Porites growth anomalies (PorGA), Porites tissue loss (PorTL), Porites trematodiasis (PorTrem), and Montipora white syndrome (MWS), and their interactions with 17 predictor variables were modeled using boosted regression trees (BRT) within a reef system in Hawaii. Each disease showed distinct associations with the predictors. Environmental predictors showing the strongest overall associations with the coral diseases were both biotic and abiotic. PorGA was optimally predicted by a negative association with turbidity, PorTL and MWS by declines in butterflyfish and juvenile parrotfish abundance respectively, and PorTrem by a modal relationship with Porites host cover. Incorporating interactions among predictor variables contributed to the predictive power of our models, particularly for PorTrem. Combining diseases (using overall disease prevalence as the model response), led to an average six-fold increase in cross-validation predictive deviance over modeling the diseases individually. We therefore recommend coral diseases to be modeled separately, unless known to have etiologies that respond in a similar manner to particular environmental conditions. Predictive statistical modeling can help to increase our understanding of coral disease ecology worldwide.

http://www.biologicaldiversity.org/news/press_releases/2009/ocean-acidification-04-14-2009.html

For Immediate Release, April 14, 2009

Contact: Miyoko Sakashita, Center for Biological Diversity, (415) 436-9682 x 308 or (510) 845-6703 (cell)

EPA Evaluates Ocean Acidification as a Threat to
Water Quality Under Clean Water Act;

Action Marks First Step Toward Regulation of
Carbon Dioxide Emissions Under the Clean Water Act

SAN FRANCISCO— The United States Environmental Protection Agency announced steps to protect U.S. waters from the threat of ocean acidification under the Clean Water Act. Today, EPA issued a notice of data availability to be published in the Federal Register that calls for information and data on ocean acidification that the agency will use to evaluate water-quality criteria under the Clean Water Act.

The notice responded to a formal petition and threatened litigation from the Center for Biological Diversity that sought to compel the agency to impose stricter pH criteria for ocean water quality and publish guidance to help states protect American waters from ocean acidification. EPA’s notice marks the first time that the Clean Water Act will be invoked by the agency to address ocean acidification.

“Ocean acidification is likely the greatest threat to the health of our oceans and is occurring at a frightening rate,” said Miyoko Sakashita, an attorney with the Center for Biological Diversity’s oceans program. “The federal government has finally acknowledged that ocean acidification is a threat; now it must take the next step and fully implement the Clean Water Act to protect our nation’s waters from ‘the other CO2 problem.’ ”

EPA’s water-quality criteria are relevant to preventing ocean acidification because they are the measure against which many states gauge the need to impose regulations on pollution. The notice states that EPA’s “recommended criteria provide guidance to States and authorized Tribes in adopting water quality standards that ultimately provide a basis for controlling discharges or releases of pollutants.” Here, that could eventually translate into controls on CO2.

The oceans absorb CO2 to the tune of 22 million tons each day, and this changes seawater chemistry, causing it to become more acidic. Ocean acidification is emerging as a primary threat to our oceans. To prevent the worst impacts of ocean acidification, CO2 emissions will need to be reduced from current levels, requiring immediate regulatory action.

Ocean acidification is degrading seawater quality, with adverse impacts on marine ecosystems. The primary known consequence of ocean acidification is that it impairs the ability of marine animals to build and maintain their protective shells and skeletons. For example, ocean acidification threatens to erode away coral reefs within our lifetime. Nearly every marine animal with a shell is vulnerable to the impacts of ocean acidification. According to the notice, “[i]mpacts to shellfish and other calcifying organisms that represent the base of the food web may have implications for larger organisms that depend on shellfish and other calcifying organisms for prey.”

In 2007, the Center filed a formal petition asking EPA to impose stricter pH criteria for ocean water quality and publish guidance to help states protect U.S. waters from ocean acidification. The federal Clean Water Act requires the EPA to update water-quality criteria to reflect the latest scientific knowledge. Since the agency developed the pH standard back in 1976, an extensive body of research has developed on the impacts of carbon dioxide on the oceans. Now, EPA has agreed to evaluate this pH criterion in light of the new information on ocean acidification.

“We must take immediate action to address ocean acidification or the impacts will be catastrophic,” said Sakashita. “Fortunately, we need not wait for new legislation addressing CO2 emissions, as the Clean Water Act already provides us with important tools to confront this problem.”

EPA is accepting data and information on ocean acidification for 60 days. If the EPA strengthens the pH water-quality criterion for oceans, then the Clean Water Act requires states to adopt a water-quality standard at least as protective as the one established by the EPA. Here, stronger water-quality standards for pH could translate into measures that regulate CO2, which is causing ocean acidification.

More information is available from the Center for Biological Diversity at http://www.biologicaldiversity.org/campaigns/ocean_acidification/index.html.

The Center for Biological Diversity is a nonprofit conservation organization with 200,000 members and online activists dedicated to protecting endangered species and wild places. www.biologicaldiversity.org

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Wednesday, Apr 8, 2009 6:43AM / Standard Entry
FEWER FISH IN CARIBBEAN REEFS
Nils Bruzelius- The Washington Post

Populations of both large and small fish have been declining sharply across the Caribbean in the past 10 years, say researchers, who combined data from 48 studies of 318 coral reefs conducted over more than 50 years.

The data show that fish “densities” that had held steady for decades began to drop significantly around 1995, a trend not reported previously. Although overfishing has long taken a toll on larger species, the drop in smaller species that are not fished indicates that other forces are at work, said author Michelle Paddack of Simon Fraser University in Canada.

Drastic losses in coral cover and changes in coral reef habitats, driven by warming water temperatures and coral diseases, as well as sediment and pollution from coastal development could be among the factors. Overfishing may also have secondary effects by removing species that help keep reefs free of harmful algae.

“All these factors are stressing the reefs and making them less able to recover from disturbances such as hurricanes, which also seem to be occurring more frequently,” Paddack said in a statement.

Paddack and her colleagues reported last week in the journal Current Biology that fish densities have been declining by 2.7 percent to 6 percent every year all across the Caribbean.

“If we want to have coral reefs in our future,” the researcher said, “we must ensure that we reduce damage to these ecosystems,” by such personal measures as not eating species that are in decline and by pushing lawmakers and resource managers for changes in how coral habitats are sustained and protected.