The coastal ocean is a highly dynamic and vital biogeochemical mediator between land and sea. Coastal waters frequently experience poor water quality: this is partly due to submarine groundwater discharges, in which polluted water is released at the bottom of the ocean. These discharges are relatively poorly understood, and research is ongoing to characterise them.
Today, Dr Tristan McKenzie from the University of Gothenburg, Sweden, presented the results of a study across the Baltic Sea, in which the concentration of Radium isotopes in ocean water was measured and used to quantify vertical mixing across the water column.
During this study, radium and silicate concentration profiles were collected from 50 stations along a ~ 5000 km cruise track in the Baltic Sea. This enabled estimating the vertical mixing rate of ocean water using a diffusion-advection model. Dr McKenzie’s research group estimated the diffusion coefficient in the Baltic Sea to be of order 10-4 m2/s, consistent with the literature. Dr McKenzie will soon take up a new role at Imperial College London, and we look forward to collaborating with him and his team in the future.