Rising Acid In Oceans Is Worsening Industry Toxins



Rising Acid In Oceans Is Worsening Industry Toxins

12 February 2013, by Harriet Jarlett

Acidification of UK waters may make industrially-contaminated sediments more toxic over time, say scientists.

Marine animals may be harmed by several stress factors

The study looked at crustaceans that feed on the surface of sediments from dredged ports and estuaries.

It found that ocean acidification, caused by climate change, causes sediments contaminated with metal to become more toxic. This can result in significant DNA damage for the animals that graze on these sediments.

'The combined effect on these animals, of coping with adapting to climate change as well as increased toxin levels, could prove to be fatal,' says Dave Sheahan, from the Centre for Environment, Fisheries and Aquaculture Science (Cefas), senior researcher on the study.

Cefas already monitors the sediments from industrialised estuaries, such as the Tees in northeast England, for poisonous metal particles. These areas must be regularly dredged to maintain harbour entrances, and the excess material has to be tested for its toxicity.

'Some organisms, may be able to move more or less to regulate for these changes. So there will be some trade off in behaviour.'

Dr Silvana Birchenough - Cefas

The scientists placed dredged material from one of these sites into laboratory tanks, then introduced burrowing crustaceans which normally graze on the sediment surface. Next, they exposed the creatures to water with levels of acid found in seawater today, as well as acid levels predicted for the next 50 and 100 years. Animals that survived ten days in these tanks were then tested to see if they incurred DNA damage.

The animals experienced significant DNA damage, which rose with acidification levels, suggesting that when acidification is combined with metal in sediments it can be more harmful.

But the study also showed that as toxicity of ingested metals rises, animals are sometimes able to adapt their behaviour to cope.

Dr Silvana Birchenough, senior benthic ecologist and co-author of the study, describes how 'initially you can see the distinct burrows they made, but after treatment there was less activity, some species were just sat on top without moving much. This shows us how some organisms, may be able to move more or less to regulate for these changes. So there will be some trade off in behaviour.'

Sheahan explained that scientists may now find a certain species tolerance is worse, and over time that species would be outcompeted by other groups. Although they expect some species to be able to survive better, or some genotypes within species better able to tolerate changes.

At the moment dredged sediments are monitored and if toxicity falls below a predetermined threshold they are considered safe to deposit in the sea. However, rising ocean acid levels may put more stress on the animals, on top of the metal toxicity, meaning current threshold values will need to be changed to make sure all marine animals, including crustaceans, are protected.

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Ocean acidification is a topic so very important to the web of life and to the biodiversity of our planet. Yet, it is hardly if ever discussed nor is it readily seen as part of the climate crisis when it is a primary part of it. Even as a climate presenter I have to admit that much more time is concentrated on the affects of CO2 on our atmosphere and not nearly enough time on our oceans. Since we already know that oceans cover nearly three quarters of our planet and all life eminates from them it would seem logical that the effects of climate change and pollution would be paramount in discussions of our continued existence as a species and others. This article and study make it clear that we are not only changing the chemical makeup of our oceans but affecting the species that live there to the point of actually interfering in the evolution of them.

This is the conundrum we face with our environment as a whole. Our inability to see the rhythm of life we are changing to the detriment of outselves thinking that the "progress" we are creating will somehow work to overcome the longlasting damage we are doing to all around us. The main tenet of our existence as humans should be do no harm. For in that tenet lies the secret to our own happiness and oneness with nature that brings us knowledge of the true riches of this world.

I am heartbroken to see what we are doing to the oceans of our world. Industrial pollution, waste, toxins, poisons, oil, nitrogen fertilizers, pharmaceuticals, all working against the very rhythm of life we need to keep ourselves thriving. All life thrives because of our oceans and now the CO2 we are also saturating them with in conjuction with our waste and pollution is working to change the chemical makeup and biodiversity of them. Some species may be able to adapt, yet others that would otherwise thrive without man's harmful intervention will not. How can we in good conscience sit by and watch while a biocide occurs at our hands? Our march to progress in human terms is not what the world as a whole is measured by. Therein lies the disconnect between us and the symbiosis we need in order to finally see the light to a better future. Our oceans are our lifeline as are all the species in it that serve a distinct and beautiful purpose. The sooner we realize we are one as a species with them and work in tandem to protect our environment as a whole the sooner we may be able to heal.

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