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January 26, 2010, Vol. 15, No. 2
In This Issue
Science in the NewsCarbon Emissions Increasing Acidity of Ocean, Threatening Marine LifeIndustrial nations that attended the Climate Change Conference in Copenhagen this past December have until the end of this month to submit their plans for reducing carbon emissions to the secretariat of the United Nations Framework Convention on Climate Change (UNFCCC)—although the UNFCCC head, Yvo de Boer, stated in a webcast on January 20 that the targets are not legally binding and the deadline is flexible.
The decisions these nations make now could have lasting impacts on marine life, as increasing levels of carbon dioxide in the ocean are making seawater increasingly acidic and, potentially, impeding the survival of many marine organisms. The ocean absorbs approximately one-third of the carbon dioxide that is emitted by the burning of fossil fuels, which mitigates the impacts of climate change but results in the ocean becoming increasingly acidic. Already, as a recent report from Oceana points out, the ocean is one-third more acidic than it was prior to the Industrial Revolution. According to a new study in the journal Science, this change in the ocean's chemistry may reduce populations of phytoplankton that form the base of marine food webs. Dalin Shi and colleagues from the Department of Geosciences at Princeton University found that increased seawater acidity decreases the iron intake of phytoplankton. Such a decrease in iron appears to impair phytoplankton's ability to photosynthesize, potentially reducing their populations and hence affecting other ocean life throughout the marine food web. However, the authors note some of this process could be countered by climate change, which could increase storms that blow iron-rich dust—from, for example, the deserts of Australia and Africa—onto the ocean, where it may eventually settle into surface waters. Additionally, other non–iron-dependent species may fill the void left by declining phytoplankton numbers. "We're just at the beginning of research on ocean acidification," said study co-author Francois Morel in a press release to announce the findings. "This is the first study published of its kind that looks at uptake of a critical nutrient." Many previous studies of the impacts of ocean acidification have focused on a decrease in the availability in seawater of carbonate ions, a vital component of the calcium carbonate shells and skeletons of a variety of marine species, including corals, urchins, oysters, clams and mussels. In a low-carbonate ocean, such animals experience greater difficulty in forming their skeletons and shells, and those structures are likely also to prove thinner, less robust and ultimately vulnerable to dissolution. Such species are at particular risk in the polar regions, largely because calcium carbonate dissolves more readily in lower temperatures. A recent study in the journal Antarctic Science examined what happened when shells from several calcifying Antarctic marine organisms were placed in seawater with a pH of 7.4, a level of acidity that, given present rates of carbon dioxide emissions, researchers predict could occur in coastal waters by the year 2300. Within 35 days of immersion in the water, shells of all four species showed significant signs of deterioration. Another study, in the journal Biogeosciences, found that shell growth rates of the pteropod (pelagic shelled mollusk) Limacina helicina, a key component of Arctic marine ecosystems, declined by 28 percent in seawater with a pH of 7.78. This is a level of acidity some scientists predict the ocean will reach by 2100. The study's authors conclude that their research supports the "concern for the future of pteropods in a high-CO2 world, as well as of those species dependent upon them as a food resource," noting that a decline in these species' populations "would likely cause dramatic changes to the structure, function and services of polar ecosystems." If nations do not reduce their emissions dramatically, the Oceana report warns, "scientists project a massive extinction of corals worldwide by the end of this century. As reefs disappear, many commercially important fish species that depend upon reef services will also be in danger." Sources: Comeau, S., et al. 2009. Impact of ocean acidification on a key Arctic pelagic mollusc (Limacina helicina) Biogeosciences 6:1877-1882; Harrould-Kolieb, E., et al, 2009. Major Emitters Among Hardest Hit by Ocean Acidification. Washington, D.C.: Oceana, 12 pp.; McClintock, J.B., et al., 2009. Rapid dissolution of shells of weakly calcified Antarctic benthic macroorganisms indicates high vulnerability to ocean acidification. Antarctic Science 21(5): 449-456; Shi, D., et al. 2010. Effect of ocean acidification on iron availability to marine phytoplankton. Science Express 10.1126/science.1183517. Science BriefsTwo Skate Species, Not One, At Danger of Extinction
The European common skate has previously been described as the first clear case of a fish species brought to the brink of extinction by commercial fishing. But a recent study in the journal Aquatic Conservation has shown that the situation is even more dire than had previously been supposed, and that what had been assumed to be one species is in fact two, both of which are now at imminent risk of extinction. Nineteenth-century researchers initially described two species of European skate, the flapper skate Dipturus intermedia and blue skate D. flossada. However, a 1926 study argued that the two should be combined as one species, D. batis, which is how the species has subsequently been classified. DNA studies of skate caught by French fishing fleets have confirmed that the original analysis was correct, and that there are indeed two species of European skate. According to the studies, which were led by Samuel Iglesias of France's Museum of Natural History, the flapper skate is the larger of the two species and reaches sexual maturity at a later age, meaning the likelihood of individuals being caught in nets before sexual maturity is that much greater. However, Iglesias and colleagues recommend that both species retain the Critically Endangered listing on the IUCN Red List currently held by D. batis. They conclude that "the risk of extinction of these depleted species is higher than previously assessed and appears unavoidable without immediate and incisive conservation action." Source: Iglesias, S., et al. In press. Taxonomic confusion and market mislabelling of threatened skates: important consequences for their conservation status. Aquatic Conservation: Marine and Freshwater Ecosystems. DOI: 10.1002/aqc.1083 Contact: Samuel Iglesias, Station de Biologie Marine de Concarneau, France. E-mail: iglesias@mnhn.fr Governments, as Well as Consumers, Vital to Sustainable Seafood Efforts
Although consumer-focused seafood campaigns have proven successful in alerting the public to overfishing and have helped provide protection for some species, their ongoing usefulness is challenged by, among other things, unclear and unreliable sourcing. According to a new overview in the journal Oryx, "There is simply too much cheating in the marketplace (e.g., mislabelling), too much misleading information, too many inconsistencies and, so far, too few results," argue Jennifer Jacquet of the University of British Columbia and colleagues. Jacquet and co-authors propose that future and ongoing market-based efforts should be goal-oriented—for example, setting specific national and international consumption targets—and could be more effective in reaching those goals by focusing on large retailers rather than individual consumers. Additionally, they argue it is important that consumer campaigns not be conducted in isolation from policy measures: "Even within a market-based approach there is a need to ensure that information is correct and that conservation efforts are not obstructed by harmful subsidies," they write. "In other words, working with consumers and retailers also brings the imperative of working with governments." Source: Jacquet, J., et al. 2010. Conserving wild fish in a sea of market-based efforts. Oryx 44(1):45-56. Contact: Jennifer Jacquet, Sea Around Us Project, University of British Columbia Fisheries Centre. E-mail: jjacquet@fisheries.ubc.ca. Daniel Pauly, a co-author on this paper and principal investigator of the Sea Around Us Project, is the keynote speaker at this year's Seafood Summit, which begins January 31, 2010. See www.seafoodchoices.org/seafoodsummit.php#keynote for more information. Research, Protection from Fisheries Help Wildlife on Great Barrier Reef
Coral trout have undergone a "spectacular recovery" in areas of the Great Barrier Reef in Australia where they have been protected from commercial fishing, say researchers. According to David Wachenfeld, chief scientist at the Great Barrier Reef Marine Park Authority, on a majority of reefs that were closed to fishing, coral trout numbers rebounded by between 31 and 75 percent after as little as 18 months to two years. Wachenfeld said that such zoning measures, and the research that informed them, have been crucial in protecting and building the resilience of the Great Barrier Reef system, even at a time when the hottest decade on record accentuated the growing pressures reef systems face. "The key role of research in ensuring the Great Barrier Reef remained one of the healthiest reef ecosystems in the world during the last decade cannot be overstated," he said. Contact: Communications Unit, Great Barrier Reef Marine Park Authority. E-mail: media@gbrmpa.gov.au For Further Information: The Great Barrier Reef Marine Park Authority has produced The Great Barrier Reef Outlook Report 2009, a summary of the past and present condition of the environmental, economic and social values of the Great Barrier Reef and a presentation of its possible future. It may be downloaded in PDF form at: www.gbrmpa.gov.au/corp_site/about_us/great_barrier_reef_outlook_report |
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