Plankton Death To Come with Acid Oceans and Sunlight

A number of marine diatom cells (Pleurosigma), which are an important group of phytoplankton in the oceans.
Credit: Michael Stringer

Global Warming has made oceans 30% more acidic already

“It’s clear we are conducting a giant experiment on the planet and we don’t know what we are doing.”

[This is a repost from my May 8 2012 article – see here for more on acid ocean impacts — Stephen]

 By Stephen Leahy

UXBRIDGE, Canada, May 8, 2012 (IPS)

Without major reductions in the use of fossil fuels, sunlight will kill an unknown number of ocean phytoplankton, the planet’s most important organism, a new study reports this week.

Not only are phytoplankton, also known as marine algae, a vital component in the ocean’s food chain, they generate at least half of the oxygen we breathe.

In the not so distant future, sunlight, the very source of life for phytoplankton, will likely begin to kill them because of the ocean’s increasing acidity, researchers from China and Germany have learned.

“There’s a synergistic effect between increased ocean acidity and natural light,” says Ulf Riebesell of the Helmholtz Centre for Ocean Research in Kiel, Germany.

Riebesell added that it was also possible “phytoplankton could adapt”.

Researchers were surprised to discover that diatoms, one of the most important and abundant types of phytoplankton, fared very badly during shipboard experiments conducted by co-author Kunshan Gao, from the State Key Laboratory of Marine Environmental Science at Xiamen University, Xiamen China.

Previous experiments in labs like Riebesell’s found that diatoms actually did better in high-acid seawater, unlike most other shell- forming plankton. Burning fossil fuels has made the oceans about 30 percent more acidic researchers discovered less than 10 years ago. Oceans absorb one third of the carbon dioxide (CO2) emitted from using fossil fuels.

The good news is this has slowed the rate of global warming. The bad news is oceans are now more acidic and it will get worse as more CO2 is emitted. This is basic, well-understood ocean chemistry.  Continue reading

Revealed: In Acidic Oceans Sunlight Kills Planet’s Most Important Organism — Marine Algae

A number of marine diatom cells (Pleurosigma), which are an important group of phytoplankton in the oceans.
Credit: Michael Stringer

“There’s a synergistic effect between increased ocean acidity and natural light”

“It’s clear we are conducting a giant experiment on the planet and we don’t know what we are doing.”

 By Stephen Leahy

UXBRIDGE, Canada, May 8, 2012 (IPS)

Without major reductions in the use of fossil fuels, sunlight will kill an unknown number of ocean phytoplankton, the planet’s most important organism, a new study reports this week.

Not only are phytoplankton, also known as marine algae, a vital component in the ocean’s food chain, they generate at least half of the oxygen we breathe.

In the not so distant future, sunlight, the very source of life for phytoplankton, will likely begin to kill them because of the ocean’s increasing acidity, researchers from China and Germany have learned.

“There’s a synergistic effect between increased ocean acidity and natural light,” says Ulf Riebesell of the Helmholtz Centre for Ocean Research in Kiel, Germany.

Riebesell added that it was also possible “phytoplankton could adapt”.

Researchers were surprised to discover that diatoms, one of the most important and abundant types of phytoplankton, fared very badly during shipboard experiments conducted by co-author Kunshan Gao, from the State Key Laboratory of Marine Environmental Science at Xiamen University, Xiamen China.

Previous experiments in labs like Riebesell’s found that diatoms actually did better in high-acid seawater, unlike most other shell- forming plankton. Burning fossil fuels has made the oceans about 30 percent more acidic researchers discovered less than 10 years ago. Oceans absorb one third of the carbon dioxide (CO2) emitted from using fossil fuels.

The good news is this has slowed the rate of global warming. The bad news is oceans are now more acidic and it will get worse as more CO2 is emitted. This is basic, well-understood ocean chemistry.  Continue reading

Oceans Becoming Hot, Sour and Breathless

Oceans home to 80% of all life — plankton provide 50 percent of the oxygen we breathe

By Stephen Leahy

DURBAN, South Africa, Dec 3 (IPS)

The world’s oceans are becoming hot, sour and breathless – threatening a vital source of food for a billion people mainly in the developing world experts warned today at a special Oceans Day event at the UN climate negotiation.

Oceans are home 80 percent of all life on the planet and emissions from fossil fuels are turning them increasingly acidic, raising water temperatures and reducing the amount of oxygen in some regions said oceanographer Carol Turley from Plymouth Marine Laboratory in the UK.

“We don’t know what all the consequences will be. We suspect the combination of all three will be far worse than one alone,” Turley told IPS in an interview on the sidelines of climate treaty negotiations known as COP 17.

It was only a few years ago that researchers realised that human emissions of carbon dioxide (CO2) was making the surface waters of oceans more acidic. The oceans naturally absorb CO2 from the atmosphere and have now absorbed about a third of all human emissions. That has kept the climate from warming faster but the additional carbon is altering the oceans’ chemistry making them 30 percent more acidic.

One documented impact is that shell-forming creatures like plankton produce thinner shells in more acidic ocean waters. These species are often very important parts of the marine food chain. As emissions of CO2 into the atmosphere increase the more the ocean sours.

[See a powerful 11 min film on Ocean acidification]

In less than ten years at least 10 per cent of the Arctic Ocean surface waters will be too acid for shell-forming species like plankton. By 2040 most of the Arctic Ocean will be too acidic as will significant areas of the Antarctic Ocean said Turley.

Change in sea water acidity pH caused by anthr...The cold waters of the polar regions allow more CO2 to be absorbed faster. The oceans haven’t seen a rapid change like this in 60 million years, she explained.

“But there will also be strange impacts. New research is showing changes in growth, behaviour and reproduction in a variety of non-shell forming species.”

Estuaries and ocean upwelling zones that are often important fishing grounds are also regions where acidification is fastest. Those areas are also subject to low oxygen levels and increasing temperatures creating new conditions in the oceans that no marine species has ever had to cope with.

Oceans are also absorbing most of the extra heat trapped by the additional CO2 in the atmosphere. Again, without this land temperatures would far higher and extreme weather events far worse.

“There is some evidence that some crab species cannot tolerate higher temperatures when ocean is more acidic,” she said.

Continue reading