Ocean acidification rates pose disaster for marine life, major study shows

Report launched from leading marine scientists at Copenhagen summit shows seas absorbing dangerous levels of CO2

Severin Carrell guardian.co.uk 10 Dec 09;

The world's oceans are becoming acidic at a faster rate than at any time in the last 55m years, threatening disaster for marine life and food supplies across the globe, delegates at the UN climate conference in Copenhagen have been warned.

A report by more than 100 of Europe's leading marine scientists, released at the climate talks this morning, states that the seas are absorbing dangerous levels of carbon dioxide as a direct result of human activity. This is already affecting marine species, for example by interfering with whale navigation and depleting planktonic species at the base of the food chain.

Ocean acidification – the facts says that acidity in the seas has increased 30% since the start of the industrial revolution. Many of the effects of this acidification are already irreversible and are expected to accelerate, according to the scientists.

The study, which is a massive review of existing scientific studies, warns that if CO2 emissions continue unchecked many key parts of the marine environment – particularly coral reefs and the algae and plankton which are essential for fish such as herring and salmon – will be "severely affected" by 2050, leading to the extinction of some species.

Dr Helen Phillips, chief executive of Natural England, which co-sponsored the report, said: "The threat to the delicate balance of the marine environment cannot be overstated - this is a conservation challenge of unprecedented scale and highlights the urgent need for effective marine management and protection."

Although oceans have acidified naturally in the past, the current rate of acidification is so fast that it is becoming extremely difficult for species and habitats to adapt. "We're counting it in decades, and that's the real take-home message," said Dr John Baxter a senior scientist with Scottish Natural Heritage, and the report's co-author. "This is happening fast."

The report, published by the EU-funded European Project on Ocean Acidification, a consortium of 27 research institutes and environment agencies, states that the survival of a number of marine species is affected or threatened, in ways not recognised and understood until now. These species include:

• whales and dolphins, who will find it harder to navigate and communicate as the seas become "noisier". Sound travels further as acidity increases. Noise from drilling, naval sonar and boat engines is already travelling up to 10% further under water and could travel up to 70% further by 2050.

• brittle stars (Ophiothrix fragilis) produce fewer larvae because they need to expend more energy maintaining their skeletons in more acid seas. These larvae are a key food source for herring.

• tiny algae such as Calcidiscus leptoporus which form the basis of the marine food chain for fish such as salmon may be unable to survive.

• young clownfish will lose their ability to "smell" the anemone species that they shelter in. Experiments show that acidification interferes with the species' ability to detect the chemicals that give "olfactory cues".

The report predicts that the north Atlantic, north Pacific and Arctic seas – a crucial summer feeding ground for whales - will see the greatest degree of acidification. It says that levels of aragonite, the type of calcium carbonate which is essential for marine organisms to make their skeletons and shells, will fall worldwide. But because cold water absorbs CO2 more quickly, the study predicts that levels of aragonite will fall by 60% to 80% by 2095 across the northern hemisphere.

"The bottom line is the only way to slow this down or reverse it is aggressive and immediate cuts in CO2," said Baxter. "This is a very dangerous global experiment we're undertaking here."

Written for policy makers and political leaders, the document is being distributed worldwide, with 32,000 copies printed in five major languages including English, Chinese and Arabic. Every member of the US congress, now struggling to agree a binding policy on CO2 emissions, will be sent a copy.

Congressman Brian Baird, a Democrat representative from Washington state, who championed a bill in Congress promoting US research on ocean acidification, said these findings would help counter climate change sceptics, since acidification was easily and immediately measurable.

"The consequences of ocean acidification may be every bit as grave as the consequences of temperature increases," he said. "It's one thing to question a computer extrapolation, or say it snowed in Las Vegas last year, but to say basic chemistry doesn't apply is a real problem [for the sceptics]. I think the evidence is really quite striking."

Oceans absorb a quarter of annual emissions: report
Reuters 11 Dec 09;

COPENHAGEN (Reuters) - The world's oceans absorb about a quarter of all carbon dioxide emitted by humans each year and it is making the water so acidic it could start dissolving some cold water corals, scientists said on Thursday.

The oceans are acting as a giant storage locker for the main gas causing global warming, but at a cost to all marine life, said a report from the European Project on Ocean Acidification.

More acidic seas could weaken shells and damage creatures that build them, block chemicals that fish use to find their homes and make life noisier for dolphins as some sounds travel better in water that has soaked up carbon -- among other effects researched by scientists in recent years.

"It is a global phenomenon that will be felt hardest and first in the polar regions but this doesn't mean that warm water (regions) will not be affected," Carol Turley from the Plymouth Marine Laboratory told a news conference on the sidelines of climate talks in Copenhagen.

Small island nations that rely on tourism for much of their income fear reefs that draw divers and snorkelers will deteriorate or die as oceans become too acidic for corals, already suffering from warmer water temperatures.

Seas are already about one third more acidic than they were at the start of the Industrial Revolution and will become more so as emissions increase. The changes are believed to be the fastest for 55 million years, the report said.

Turley said world leaders should keep carbon dioxide concentrations in the atmosphere at no more than 450 parts per million to ward off the most dramatic changes.

"A substantial and urgent reduction in carbon dioxide emissions is the only solution. There is no geo-engineering that will help," she said, referring to large-scale projects proposed to limit warming without capping carbon dioxide emissions.

Oceans are often left out of climate talks, or have a lower profile, because the science is less well-known and perhaps because humans live on land and focus on their immediate surroundings, said Carl Gustaf Lundin, head of the marine programme at the International Union for Conservation of Nature.

But changes now cannot be undone for generations.

"It will take tens of thousands of years for the carbon dioxide to disappear, essentially to be buffered by the ocean chemistry and sediments. So it is not a short-term problem," Turley said.

Scientists say increasingly acidic oceans are disrupting the process of calcification used by sea creatures to build shells as well as coral reefs.

For example, tiny amoeba-like animals called foraminifera, which live on the ocean's surface, play a major role in trapping CO2 and transporting it to the ocean depths where it can be locked away for decades or centuries.

The Southern Ocean between Australia and Antarctica is the largest of the ocean carbon sinks and disruption of the shell-building process could have a major impact on the ability of oceans to soak up CO2, scientists say.

(Reporting by Emma Graham-Harrison; Editing by Janet Lawrence)