Published 21 April 2017
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’
Published 4 April 2017
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’
Published 23 February 2017
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’
Published 16 February 2017
As the world continually emits carbon dioxide into the atmosphere, the oceans are taking a hit, absorbing some of it and growing more acidic. Among other effects, scientists have found that coral reefs and oyster hatcheries are deteriorating as a result. However, scientists studying a type of sea snail report a bit of bright news in the ACS journal Environmental Science & Technology: The animal can adapt by rejiggering its shell-making process and other functions.
A lower pH in ocean waters means fewer carbonate ions are available to calcifying organisms, such as coral reefs and oysters, which need the ions to produce shells and skeletons. While ocean acidification appears to cause damage to many calcifying organisms, recent studies have suggested that some of those organisms may be more resistant to acidification than previously thought. Sean D. Connell and colleagues wanted to find out how this might be possible.
Continue reading ‘Some marine creatures may be more resilient to harsher ocean conditions than expected’
Published 3 February 2017
Climate-driven disturbances are having profound impacts on coastal ecosystems, with many crucial habitat-forming species in sharp decline. However, among these degraded biomes, examples of resilience are emerging. Writing in BioScience, Jennifer O’Leary, a California Sea Grant Marine Biologist based at Polytechnic State University, and her colleagues describe these recoveries and highlight the possible implications for ecosystem-sparing management.
To gain insight into disturbed coastal habitats, the authors surveyed 97 marine experts about their observations of climate-induced perturbations, including extreme storms, temperature changes, and ocean acidification. Eighty percent of those who had witnessed climate extremes also identified evidence of habitat resistance or rapid recovery. According to O’Leary and her colleagues, the survey results indicated that “bright spots of ecosystem resilience are surprisingly common across six major coastal marine ecosystems.” In some cases, resilience was marked by striking recoveries. In one bleaching event in Western Australia, up to 90% of live coral was lost as a result of severe bleaching. Despite reaching a low of 9% unbleached area, the healthy reef surface recovered to 44% within 12 years.
Continue reading ‘Marine ecosystems show resilience to climate disturbance’
Published 30 January 2017
Fact: More carbon dioxide (CO2) in the air also acidifies the oceans. It seemed to be the logical conclusion that shellfish and corals will suffer, because chalk formation becomes more difficult in more acidic seawater. But now a group of Dutch and Japanese scientists discovered to their own surprise that some tiny unicellular shellfish make better shells in an acidic environment. This is a completely new insight.
Researchers from the NIOZ (Royal Dutch Institute for Sea Research) and JAMSTEC (Japanese Agency for Marine-Earth Science and Technology) found in their experiments that so-called foraminifera might even make their shells better in more acidic water. These single-celled foraminifera shellfish occur in huge numbers in the oceans. The results of the study are published in the leading scientific journal Nature Communications.
Since 1750 the acidity of the ocean has increased by 30%. According to the prevailing theory and related experiments with calcareous algae and shellfish, limestone (calcium carbonate) dissolves more easily in acidic water. The formation of lime by shellfish and corals is more difficult because less carbonate is available under acidic conditions. The carbonate-ion relates directly to dissolved carbon dioxide via two chemical equilibrium reactions.
Continue reading ‘Unexpected result: Ocean acidification can also promote shell formation’
Published 27 January 2017
For Bill Mook, coastal acidification is one thing his oyster hatchery cannot afford to ignore.
Mook Sea Farm depends on seawater from the Gulf of Maine pumped into a Quonset hut-style building where tiny oysters are grown in tanks. Mook sells these tiny oysters to other oyster farmers or transfers them to his oyster farm on the Damariscotta River where they grow large enough to sell to restaurants and markets on the East Coast.
The global ocean has soaked up one third of human-caused carbon dioxide (CO2) emissions since the start of the Industrial Era, increasing the CO2 and acidity of seawater. Increased seawater acidity reduces available carbonate, the building blocks used by shellfish to grow their shells. Rain washing fertilizer and other nutrients into nearshore waters can also increase ocean acidity.
Back in 2013, Mook teamed up with fisherman-turned-oceanographer Joe Salisbury of the University of New Hampshire to understand how changing seawater chemistry may hamper the growth and survival of oysters in his hatchery and oyster farm.
Continue reading ‘New tool helps oyster growers prepare for changing ocean chemistry’