Archive for the 'Press releases' Category

Cold-water corals: acidification harms, warming promotes growth

Because they build their skeletons from calcium carbonate, cold-water corals such as the globally distributed species Lophelia pertusa are considered particularly threatened by ocean acidification. This change in seawater chemistry, caused by the absorption of carbon dioxide (CO2) from the atmosphere, reduces the concentration of carbonate ions. With fewer carbonate ions, calcification becomes more difficult. However, laboratory studies at GEOMAR Helmholtz Centre for Ocean Research Kiel reveal, that a simultaneous increase in water temperatures could help Lophelia pertusa to counteract negative effects of ocean acidification. The experiments that were conducted as part of the German research programme on ocean acidification BIOACID (Biological Impacts of Ocean Acidification) demonstrate how important it is to investigate Lophelia’s response to single drivers of climate change as well as their combined effects.

On an expedition with the research vessel POSEIDON and the submersible JAGO, marine biologists from GEOMAR collected corals at Trondheim Fjord (Norway) for their investigations. “During our JAGO dives, we examined the condition of the reefs. We documented their expansion and the diverse community living in the reefs and carefully chose our samples”, explains Janina Büscher. The PhD student from the department of Biological Oceanography at GEOMAR conducted the experiments and is lead author of a publication on the effects and impact of ocean acidification and warming on the growth and fitness of Lophelia pertusa in the research journal Frontiers in Marine Science. “The richness in species of these reefs that exist in almost complete darkness and at temperatures below ten degrees Celsius is very impressive.” Many of these underwater oases, grown over centuries, are protected as natural heritages. Their diversity ensures the resilience of the fjord ecosystem, and many species of fish find shelter and food in the reefs.

Continue reading ‘Cold-water corals: acidification harms, warming promotes growth’

Rising carbon dioxide levels, ocean acidity may change crucial marine process

Climate change may be putting cyanobacteria that are crucial to the functioning of the ocean at risk as the amount of carbon dioxide in the atmosphere increases and the acidity of ocean water changes.

In a paper published Thursday in Science, a team of researchers from Florida State University, Xiamen University in China and Princeton University argue that the acidification of seawater caused by rising carbon dioxide levels makes it difficult for a type of cyanobacteria to perform a process called nitrogen fixation.

Few people know much about a type of cyanobacteria called Trichodesmium, but this miniscule collection of cells is critical to the health of hundreds of species in the Earth’s oceans. Through nitrogen fixation, Trichodesmium converts nitrogen gas into ammonia and other molecules that organisms are dependent on for survival.

Trichodesmium is thought to be responsible for about 50 percent of marine nitrogen fixation, so a decline in its ability could have a major ripple effect on marine ecosystems.

“This is one of the major sources of nitrogen for other organisms in the open ocean,” said Sven Kranz, assistant professor of Earth, Ocean and Atmospheric Science at Florida State University and a co-author of this study. “If Trichodesmium responds negatively to the environmental changes forced upon the ocean by fossil fuel burning, it could have a large effect on our food web.”

Continue reading ‘Rising carbon dioxide levels, ocean acidity may change crucial marine process’

Ocean warming to cancel increased CO2-driven productivity

University of Adelaide researchers have constructed a marine food web to show how climate change could affect our future fish supplies and marine biodiversity.

Published today in Global Change Biology, the researchers found that high CO2 expected by the end of the century which causes ocean acidification will boost production at different levels of the food web, but ocean warming cancelled this benefit by causing stress to marine animals, preventing them using the increased resources efficiently for their own growth and development. The result was a collapsing food web.

“Humans rely heavily on a diversity of services that are provided by ocean ecosystems, including the food we eat and industries that arise from that,” says project leader Professor Ivan Nagelkerken, from the University’s Environment Institute.

“Our understanding of what’s likely to happen has been hampered by an over-reliance on simplified laboratory systems centred on single levels of the food web. In this study, we created a series of three-level food webs and monitored and measured the results over a number of months to provide an understanding of future food webs under climate change.”

Continue reading ‘Ocean warming to cancel increased CO2-driven productivity’

Collaboration with new scholar and NOAA Ocean Acidification Program Show Potenital

This past month, NCCOS welcomed a new Hollings Scholar, Madison Uetrecht, who will study the effects of ocean acidification on oyster growth under Dr. Beth Turner over the summer months. They visited Mook Sea Farm, where Uetrecht will conduct out-planting experiments with juvenile oysters to assess whether shell growth and calcification changes during different field ocean acidification (OA) conditions.

Dr. Turner is the NOAA lead on a recently funded mini-grant from the NOAA Ocean Acidification Program for citizen science workshops through the Northeast Coastal Acidification Network. Monitoring guidance for coastal acidification developed by EPA will guide workshop participants in demonstrations and hands-on activities to monitor conditions in local estuaries.

Continue reading ‘Collaboration with new scholar and NOAA Ocean Acidification Program Show Potenital’

Canary in the kelp forest

The one-two punch of warming waters and ocean acidification is predisposing some marine animals to dissolving quickly under conditions already occurring off the Northern California coast, according to a study from the University of California, Davis.

In the study, published in the journal Proceedings of the Royal Society B: Biological Sciences, researchers at the UC Davis Bodega Marine Laboratory raised bryozoans, also known as “moss animals,” in seawater tanks and exposed them to various levels of water temperature, food and acidity.

The scientists found that when grown in warmer waters and then exposed to acidity, the bryozoans quickly began to dissolve. Large portions of their skeletons disappeared in as little as two months.

“We thought there would be some thinning or reduced mass,” said lead author Dan Swezey, a recent Ph.D. graduate in professor Eric Sanford’s lab at the UC Davis Bodega Marine Laboratory. “But whole features just dissolved practically before our eyes.”

Continue reading ‘Canary in the kelp forest’

Understanding how coralline algae responds to climate change

A study carried out by The University of Western Australia at the Indian Ocean Marine Research Centre in Watermans Bay has revealed for the first time that coralline algae is able to adjust its internal chemistry to respond to rising pH levels in the ocean.

Coralline algae are ecologically important algae, critical for the formation and maintenance of reefs.

They form a calcified skeleton through producing calcium carbonate which acts as a glue vital in binding reefs together, however rising pH levels in the ocean are threatening this process.

UWA researchers Dr Christopher Cornwall, Dr Steeve Comeau and Professor Malcolm McCulloch discovered that although coralline algae can be badly impacted by rising CO2 levels, some species shows greater tolerance than previously thought.

“Ocean acidification is a major threat to coralline algal dominated reefs in both temperate and tropical ecosystems,” Dr Cornwall said.

Continue reading ‘Understanding how coralline algae responds to climate change’

Deep oceans face starvation by end of century

The deep ocean floor, earth’s largest habitat, will be starved of food by the end of this century, scientists have warned.

New research published on open-access journal Elementa today shows that food supply to some areas of the Earth’s deep oceans will decline by up to half by 2100.

Dr Andrew Sweetman, based at the Lyell Centre for Earth and Marine Science and Technology at Heriot-Watt University in Edinburgh, and colleagues from 20 of the world’s leading oceanographic research centres have used earth system models and projected climate change scenarios, developed for the Intergovernmental Panel on Climate Change (IPCC), to quantify impending changes to deep oceans.

The team looked at a number of sea and ocean beds, from the Arctic to Antarctic Oceans, focusing on bathyal (200-3000m) and abyssal (3000-6000m) depths. As well as measuring how the deep oceans’ food sources will decline, the team examined the impact that increased seabed temperatures, declining oxygen levels and increasingly acidic seawater will have, under the sea and across the planet.

Sweetman, associate professor at Heriot-Watt’s Lyell Centre for Earth and Marine Science and Technology, said: “The rate of change underway in our oceans is faster than at any point we know of in geological history.

Continue reading ‘Deep oceans face starvation by end of century’


Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,001,025 hits

OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book