Ocean Acidification: Dipping a toe in changing waters.

The chief UK scientist was reported, this week, expressing serious concern about the the impacts of climate change and carbon emissions on the state of the planet's oceans. Whilst increased air temperatures have generated most discussion, there are significant changes occurring in the seas which, covering 70% of the planet, could be having a widespread impact on complex marine ecosystems that we're only just starting to explore.

The oceans are changing, and changing pretty fast. Increased atmospheric temperatures impact upon surface waters of the seas causing them to be warmer. We know this can lead to more rapid melting of Arctic ice but what is less widely known is that warmer oceans absorb more carbon dioxide. And there's more of the gas in the atmosphere to be absorbed. Put the two together and the result is the oceans are becoming more acidic. Water and carbon dioxide form carbonic acid. In the atmosphere this displays as Acid Rain, in sea water it results in Ocean Acidification. The variation in pH may not seem a lot - but it's enough for life to become harder for some marine organisms. Whilst vegetation such as seaweed may benefit from warmer, more acidic oceans, creatures that produce calcite to build a shell or protective body find it harder to generate the material under more acidic conditions. As many of these smaller crustaceans form the basis of food chains for the feeding habits of larger marine creatures the impacts upon ocean life are considerable.

One of the more immediate impacts is the bleaching of coral. There are now real concerns that the Great Barrier Reef off the NE coast of Australia is already suffering coral die-back over 40% of its extent as a result of increased ocean acidity and there are fears the world's warm-water corals will face a tougher future unless carbon emissions are significantly reduced. Some reports suggest they could be destroyed as early as 2050.

Environmental impacts are just one of the implications; there are economic effects too. Oyster farmers and fish farms are being affected with smaller yields and reduced disease-resistance. With a growing world population needing increased food supplies, this could be an issue with reduced production falling further from the needs of increased demand.

The more we study it, the more integrated the planet's system are seen to be. Burn the stored carbon from millions of years' accumulation in just a few centuries - as we do with coal, oil and gas supplies - and we impact upon not just the atmosphere, but the oceans too. Understanding the connections, systems, cycles and interactions is key if we are to check our impacts and make wise decisions for a sustainable future.