Climate Change, Acidification, & the Oceans

Loss of polar sea ice could cause an ecological tipping point

Lying underneath the polar sea-ice exists a wealth of critters who have adapted to life in these cold, dark regions.  As climate change increases the temperature at the poles, we have seen an increase in the loss of sea-ice in both the Arctic and the Antarctic.  And for the guys living underneath this means more light.

Light isn’t normally something we consider to be an issue, but for these ecosystems it could be.  Dr Graeme Clark of the University of New South Wales in Australia and colleagues have just published a piece of research that points to a light tipping point – a point at which the light levels become great enough to allow rapid ecological change in the form of algae.  Algae is super fast growing, and it can rapidly take over if conditions – especially light – are suitable… meaning it will likely out-compete the existing invertebrate community.

This isn’t something that will might happen at some point in the future – its already starting to happen.  More recent declines in sea ice already increasing the amount of light reaching these historically darker depths.

The original paper is available from the Journal Global Change Biology – here’s the link http://dx.doi.org/10.1111/gcb.12337.  Unfortunately it’s not open access.

Image:  Even where a comparably rich life was found near Seymour/Paulet fast growing life forms such as sea squirts (white globes with net-like structure), the bushy sea fans, and the branched sponges were most abundant. The red organism is also a sponge. The yellow sphere is a snail. These fast growing and mobile animals indicate that the sea-floor is regularly disturbed and recolonized.  Image and caption from the Alfred Wegener Institute for Polar and Marine Research

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