The first paper from the European Research Council project Isotope Cycling in the Labrador Sea (ICY-LAB) has been published in Progress in Oceanography.
The aims of the ambitious ICY-LAB project were to investigate the influence of meltwater, coming from the Greenland Ice Sheet, on the supply of nutrients to the oceans and how this, in turn, impacts marine biology. Dr Kate Hendry and her international and multi-discipline team have published a new paper showing how they used geochemistry, together with physical, biological, and geological data, to gain a holistic insight into the cycling of these important nutrients.
The scientific crew spent about five weeks at sea in 2017, mostly near the western coast of Greenland, sampling waters, sediments and marine life using a range of cutting-edge technologies.
For example, a Remotely Operated Vehicle (ROV) took high-definition, real time videos of the seafloor and samples of marine life, water and sediments.
Their paper highlights the importance of glacial meltwaters, combined with shelf currents and biological production, on biogeochemical cycling in these high-latitude regions over a range of timescales.
Vigorous biological uptake in the glacial fjords keeps the surface concentration of key dissolved nutrients needed for algae, such as nitrate, phosphate and silicon, very low. However, sediment particles from the glaciers reach the shelf waters, albeit in a patchy way, and are then rapidly transported away from the shore.
These particles, together with the remains of algal shells and biological material, are rapidly dissolved and cycled through shallow marine sediments. This means that the seafloor is a very important source of nutrients – especially silicon – to the overlying waters.
Future changes in the supply of these reactive, glacial sediments, as well as changes in the shelf currents that transport them, will have a profound impact on the nutrient balance and ecosystem structure in the fjords and coastal waters, and potentially even further afield.
This study shows how geochemical and oceanographic analyses can be used together to probe not only modern nutrient cycling in this region, but also changes in glacial meltwater discharge through time.
Hendry, K.R. et al. (2019) The biogeochemical impact of glacial meltwater from Southwest Greenland. Progress in Oceanography.
Accessible version can be found on Zenodo, or here.