Sunday, October 26, 2014

Ocean acidification worries noted, yet again

This BBC report paints a worrying picture of some recent research on ocean acidification.  First the UK's chief scientist:

“If we carry on emitting CO2 at the same rate, ocean acidification will create substantial risks to complex marine food webs and ecosystems.”
He said the current rate of acidification is believed to be unprecedented within the last 65 million years – and may threaten fisheries in future.

The consequences of acidification are likely to be made worse by the warming of the ocean expected with climate change, a process which is also driven by CO2.

Sir Mark’s comments come as recent British research suggests the effects of acidification may be even more pervasive than previously estimated.

Until now studies have identified species with calcium-based shells as most in danger from changing chemistry.

But researchers in Exeter have found that other creatures will also be affected because as acidity increases it creates conditions for animals to take up more coastal pollutants like copper.
The angler’s favourite bait – the humble lugworm – suffers DNA damage as a result of the extra copper. The pollutant harms their sperm, and their offspring don’t develop properly.

“It’s a bit of a shock, frankly,” said biologist Ceri Lewis from Exeter University, one of the report’s authors. “It means the effects of ocean acidification may be even more serious than we previously thought. We need to look with new eyes at things which we thought were not vulnerable.”

The lugworm study was published in Environmental Science and Technology. Another study from Dr Lewis not yet peer-reviewed suggests that sea urchins are also harmed by uptake of copper. This adds to the damage they will suffer from increasing acidity as it takes them more and more energy to calcify their shells and spines.

This is significant because sea urchins, which can live up to 100 years, are a keystone species - grazing algae off rocks that would otherwise be covered in green slime.
The article does go on to make this comment, too, but I think it is actually too optimistic a take on some recent, but still very limited, studies:
At the bottom end of the marine animal chain, tiny creatures like plankton and coccolithophores reproduce so fast that their future offspring are likely to evolve to cope with lower pH.

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