Archive for December, 2013

The state of the art in marine science raises many fascinating questions – the Society for Environmental Toxicology and Chemistry’s (SETAC’s) symposium highlights just how much we still have to learn about our planet’s oceans. What are human pressures – like the cocaine detected in Oslo’s fjord originating from the city’s waste water, or the billions of tonnes of microscopic plastic fragments accumulating in the world’s oceans – doing to marine life?

The emerging evidence on Ocean acidification is particularly striking, and a threat whichever greenhouse gas emissions path the world ends up on. I’ve always heard targets for emissions reductions described in terms of avoiding the risk of ‘dangerous climate change’ (limiting global warming to 2 degrees, although you suspect it’s not that simple). But these scenarios still involve massively higher anthropocentric emissions of carbon dioxide, which will be absorbed into the ocean.

So ocean acidification is ongoing and unavoidable – reductions in emissions can reduce its speed but more acidic oceans are inevitable. Some organisms will grow more quickly, others more slowly. For many species, acidification will mean they require more energy to survive, to regulate their internal chemistry. This means they have less energy available for growth. Overall, biological productivity is expected to reduce so ocean biomass will fall, affecting the entire food chain.

We are not going to mitigate all of humanity’s effects on the planet, so it’s a question of priorities for actions: I hope the fish are only exposed to doses of cocaine at weekends, rather than being permanently on acid.

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