Are climate scientists doom-mongering? Bulk of research on impacts of ocean acidification is FLAWED, new study finds
- Scientists have warned growing carbon emissions are leading to the oceans getting more acidic as carbon dioxide gas dissolves in sea water
- A review of 465 studies found just 27 used appropriate experimental design
- They say the flaws ‘undermine’ confidence in the impacts of acidic oceans
- It comes a month after figures revealed the Arctic ice cap regrew in 2013
For years scientists have warned that the oceans are becoming more acidic – and this spells disaster for marine life.
But a review of the bulk of laboratory studies into the phenomenon have been flawed and unreliable, experts say.
The research is the latest study to highlight difficulties with doom-mongering scientific predictions.
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A review of 465 studies on the impacts of rising ocean acidity has suggested many of them used flaw experimental techniques which ‘undermine’ their findings. Scientists and campaigners, like in the image above have been warning that ocean acidification due to rising emissions could devastate fish populations
Last month research from University College London highlighted how the ice-cap in the Arctic regrew by 40 per cent in 2013 – surprising scientists.
The United Nations has also warned the effects of acidity in the oceans could cost the world economy $1 trillion (£644 billion) by the end of the century.
Carbon dioxide – is blamed for global warming when it ends up in the air – as it helps to trap heat, preventing it from escaping into space.
However, when the gas is absorbed by the sea, as a large proportion of it is, it makes seawater more acidic.
Forecasters warn acidification will have numerous effects including wiping out valuable fisheries such as oyster beds and killing off coral reefs.
Shellfish in particular have been found to struggle to make their shells when water gets too acidic.
The earth’s seas are not yet acidic – but the opposite – slightly alkaline.
But forecasters believe it is slowly edging towards an acidic level – above the neutral midpoint of pH 7 – by 2100.
The latest review of 465 scientific studies into the effects of ocean acidification on sea life said only 27 used an ‘appropriate experimental design’.
And 278 studies were ‘clearly inappropriate’, which means a huge amount of research is not fit for purpose.
The authors say that some of the research, if ‘reanalysed’ might yield useful data, but not in its current form.
Christopher Cornwall, who studies ocean acidification at the University of Western Australia, and ecologist Catriona Hurd of the University of Tasmania wrote in the ICES Journal of Marine Science: ‘This analysis identified that the most laboratory manipulation experiments in ocean acidification research used either an inappropriate experimental design and/or data analysis, or did not report these details effectively.’
Carbon dioxide emitted into the atmopshere by burning of fossil fuels, like at the power station above, is known to act like a greenhouse gas and contribute to global warming. It can also dissolve in sea water, causing the acidity of the oceans to rise, which has led to concerns about the impact this could have on marine life
Shell fish like this marine snail have been found in laboratory experiments to suffer problems forming their shells as the water they were kept in became more acidic. Similar impacts have been seen in tests in other shellfish, raising concerns for many important fisheries
They added: ‘The tendency for the use of inappropriate experimental design also undermines our confidence in accurately predicting the effects of ocean acidification on the biological responses of marine organisms.’
To test the effect on ocean creatures – whether lobsters, plankton, mussels, or fish is a complex business.
It requires getting big tanks of seawater containing sealife to slosh around on moving tables that simulate the effect of the tides for days on end.
Seawater is made more acidic by adding chemicals – but this too is far from straightforward.
Errors made in the studies include increasing acidity without increasing temperature, not looking at other effects such as an increase of chemicals called carbonates in the water and failing to eliminate the risk of observer bias.
The authors commenting in the journal Nature, say the ‘overwhelming evidence’ of ocean acidification still stands.
But it is hard to assess the impact of ocean life from most of the experiments that have been carried out.
CLIMATE CHANGE WILL LEAVE A SOUR TASTE IN OUR MOUTHS
Marine biologists have found that shellfish take on a sour flavour if they are reared in slightly acidified sea water.
They warn that as the planet’s oceans grow more acidic, due to rising carbon dioxide levels, many of our favourite seafoods could become less appetising.
Climate change experts predict that over the next century, the levels of the world’s oceans could drop from pH8 to pH7.5.
Many have warned this could lead to shrimps and prawns struggling to build the shells and skeletons they need to survive.
Now, in the first study to test how ocean acidification could impact the taste of seafood, researchers at the University of Gothenberg and Plymouth University found it will make them sour.
During tests, shrimp raised in water with a lower pH were 2.6 times more likely to be rated as the worst tasting.
While those reared in the less acidic water were 3.4 times more likely to be judged the tastiest.
Also the 63 per cent of the shrimp from the acidic water died during the three weeks.
The results could have profound implications for the seafood industry as it suggests shellfish will become harder as their numbers dwindle, but also demand could decrease as people lose their taste for them.
ARE HERRING ALREADY FEELING THE STING OF OCEAN ACIDIFICATION
A recent study funded by the European Union found that ocean acidification is already having a profound impact on herring in the Baltic Sea.
This heavily fished area has already seen pH values of 7.2 being recorded, so scientists wanted to see what impact it was having.
They hatched eggs taken from herring caught off the coast of Norway and reared them in outdoor tanks with different levels of aciditiy.
Those reared in tanks with pH values of 7.45 and 7.07 showed more signs of organ damage than those in low acidity water.
They had more damage in the liver, kidneys and their find were often abnormally shaped while they tended to develop more slowly.
After 39 days, the fish larvae in the medium acidity tank weighed 30 per cent less than those in normal waters while those in the high acidity tank weighted 40 per cent less.
The researchers said that these smaller fish would be more at risk of being preyed upon and are less able to survive.