Tag Archives: ecosystems

The desperate race to cool the ocean before it’s too late

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Technologyreview.com, By Holly Jean Buck, April 23rd

Holly Jean Buck is a fellow at UCLA’s Institute of the Environment and Sustainability. This is an adapted excerpt from her upcoming book After Geoengineering: Climate Tragedy, Repair, and Restoration (September 2019, Verso Books).

Coral reefs smell of rotting flesh as they bleach. The riot of colors—yellow, violet, cerulean—fades to ghostly white as the corals’ flesh goes translucent and falls off, leaving their skeletons underneath fuzzy with cobweb-like algae.

Corals live in symbiosis with a type of algae. During the day, the algae photosynthesize and pass food to the coral host. During the night, the coral polyps extend their tentacles and catch passing food. Just 1 °C of ocean warming can break down this coral-algae relationship. The stressed corals expel the algae, and after repeated or prolonged episodes of such bleaching, they can die from heat stress, starve without the algae feeding them, or become more susceptible to disease.

Australia’s Great Barrier Reef—actually a 2,300-kilometer (1,400-mile) system made up of nearly 3,000 separate reefs—has suffered severe bleaching in the past few years. Daniel Harrison, an Australian oceanographer looking at what might be done to buy more time for the Great Barrier Reef, says the situation is getting dire. “There might be as little as 25% of shallow-water coral cover left from pre-anthropogenic times. We don’t really know, because nobody started surveying before 1985,” he tells me. “You’ve got less than 1% of the ocean in coral reefs, and 25% of all marine life. We’re looking at losing all of that really quite quickly, in evolutionary terms. In human-lifetime terms.”

Coral reefs are not just about colorful fish and exotic species. Reefs protect coasts from storms; without them, waves reaching some Pacific islands would be twice as tall. Over 500 million people depend on reef ecosystems for food and livelihoods. Even if the temperature increase eventually stabilizes at 1.5 °C a century or two from now, it’s not known how well coral reef ecosystems will survive a temporary overshoot to higher temperatures.

The corals are like the canary in the coal mine.

The corals are like the canary in the coal mine, Harrison says: “They’re very temperature-sensitive. I really do think it’s just a harbinger of things to come. You know, the coral ecosystem might collapse first, but I think there might be quite a few more ecosystems that’ll follow it. Life is very resilient, but ecosystems as we know them aren’t.”

Read more about corals, cooling the ocean, and climate change

New Challenges for Ocean Acidification Research

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SpaceDaily.com January 2nd, 2015
Kiel, Germany

To continue its striking development, ocean acidification research needs to bridge ocean acidification between its diverging branches towards an integrated assessment. This is the conclusion drawn by Prof. Ulf Riebesell from GEOMAR Helmholtz Centre for Ocean Research Kiel and Dr. Jean-Pierre Gattuso from the French Centre National de la Recherche Scientifique (CNRS) and Universite Pierre et Marie Curie.

In a commentary in the journal “Nature Climate Change”, the two internationally renowned experts reflect on the lessons learned from ocean acidification research and highlight future challenges.

Over the past decade, ocean acidification has received growing recognition not only in the scientific area. Decision-makers, stakeholders, and the general public are becoming increasingly aware of “the other carbon dioxide problem”. It is time to reflect on the successes and deficiencies of ocean acidification research and to take a look forward at the challenges the fastest growing field of marine science is facing.

In the January issue of the journal “Nature Climate Change” Ulf Riebesell, professor for Biological Oceanography at GEOMAR Helmholtz Centre for Ocean Research Kiel, and Jean-Pierre Gattuso from the French Centre National de la Recherche Scientifique (CNRS) urge the international scientific community to undertake a concerted interdisciplinary effort.

According to the two experts, future ocean acidification research will have to deal with three major challenges: It needs to expand from single to multiple drivers, from single species to communities and ecosystems, and from evaluating acclimation to understanding adaptation. “The growing knowledge in each of the diverging research branches needs to be assimilated into an integrated assessment”, Prof. Riebesell points out.

For the scientific community, it is obvious that ocean acidification does not occur in isolation. Rising temperatures, loss of oxygen, eutrophication, pollution and other drivers happen simultaneously and interact to influence the development of marine organisms and communities.

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Study Committee Calls for Maine to Act on Ocean Acidification

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Portland Press Herald, Dec 2nd, 2014 By Kevin Miller

A report to legislators says more research and local efforts are needed to deal with the threat to shellfish, including lobsters and clams.

AUGUSTA — Maine should increase research and monitoring into how rising acidity levels in oceans could harm the state’s valuable commercial fisheries while taking additional steps to reduce local pollution that can affect water chemistry.

Those are two major recommendations of a state commission charged with assessing the potential effects of ocean acidification on lobster, clams and other shellfish. The Legislature created the commission this year in response to concerns that, as atmospheric carbon dioxide levels have risen, the oceans have become 30 percent more acidic because oceans absorb the gas.

Researchers are concerned that organisms that form shells – everything from Maine’s iconic lobster to shrimp and the tiny plankton that are key links in the food chain – could find it more difficult to produce calcium carbonate for shells in more acidic seawater. They worry that the acidification could intensify as carbon levels rise and the climate warms.

Although research on Maine-specific species is limited, the commission of scientists, fishermen, lawmakers and LePage administration officials said the findings are “already compelling” enough to warrant action at the state and local level.

“While scientific research on the effects of ocean acidification on marine ecosystems and individual organisms is still in its infancy, Maine’s coastal communities need not wait for a global solution to address a locally exacerbated problem that is compromising their marine environment,” according to an unofficial version of the report unanimously endorsed by commission members Monday.

The panel’s report will be presented to the Legislature after Monday’s final edits are incorporated. Those recommendations include:

• Work with the federal government, fishermen, environmental groups and trained citizens to actively monitor acidity changes in the water or sediments, and organisms’ response to those changes.

• Conduct more research across various species and age groups to get a better sense of how acidification is affecting the ecosystem.

• Identify ways to further reduce local and regional emissions of carbon dioxide – a greenhouse gas produced by the combustion of fossil fuels – and to reduce runoff of nitrogen, phosphorus and other nutrients that can contribute to acidification.

• Reduce the impact of acidification through natural methods, such as increasing the amount of photosynthesizing marine vegetation like eelgrass and kelp, promoting production of filter-feeding shellfish operations, and spreading pulverized shells in mudflats with high acidity.

• Create an ongoing ocean acidification council to monitor the situation, recommend additional steps and educate the public. This recommendation is the only concrete legislative proposal contained within the report.

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