Arctic Algae

In light of the next few posts, I wanted to share some new research investigating the response of the diatom, Discostella stelligera, to climate change. Diatoms are single-celled algae, with silica cell walls, frequently used as proxies of environmental change due to their sensitivity to geochemical variables and high preservation rate. Palaeolimnological research has often attributed the changing abundance of D. stelligera over the last century in Northern Hemisphere lakes to climate change, however the exact mechanisms were poorly understood.

Saros et al. (2016) investigated the abundance of D. stelligera in two lakes in southwest Greenland in the summers of 2013-14. During the second summer, the thermal structure of one of the lakes was mechanically manipulated. It was found that despite a high natural abundance of D. stelligera in both lakes, the population dramatically declined in the lake subject to thermal manipulation. This research has been fundamental in supporting the use of D. stelligera as a proxy for climate-driven changes in lakes.

Response of the Greenland lakes in the summers of 2013 and 2014 (only the Experimental Lake was manipulated in the summer of 2014) (a and b) thickness of epilimnion (c and d) temperature of epilimnion averaged (e and f) mixed layer average light intensity (g and h) D. stelligera cell densities (Saros et al., 2016)