Scientists Monitor Health Of The Mersey

Ruzanna Harutyunyan's picture

Scientists at the University of Liverpool are monitoring nutrient concentrations in Liverpool Bay and the eastern Irish Sea to improve our understanding of how inputs from rivers impact the health of this important aquatic ecosystem.

Excessive amounts of nutrients can over-stimulate growth of microscopic marine plants known as phytoplankton, which are the source of energy for all living matter in the marine environment. This can lead to a process known as 'eutrophication', which is associated with the formation of toxic algal blooms, the reduction of oxygen in the sea, and in extreme cases, the death of marine life.

Dr Claire Mahaffey, from University's School of Earth and Ocean Sciences, is using a state-of-the-art nutrient analyser - funded by the Natural Environment Research Council's Proudman Oceanographic Laboratory (POL) - to understand how nutrients such as nitrate, ammonium and phosphate change over tidal cycles and longer periods of time. Consisting of detectors, a reaction chamber and built-in computer, the nutrient analyser can also be used on research ships at sea.


Dr Claire Mahaffey explains: "The three local rivers, the Dee, Mersey and Ribble deliver nutrients to Liverpool Bay. We collect samples from the sea surface and close to the sea bed in order to understand the tidal, seasonal and interannual changes in nutrient dynamics in the region.

"In Liverpool Bay, fresh water from the River Mersey floats on top of seawater from the Irish Sea, a process known as stratification. Combined with nutrients in the Mersey water this stratification can be an important trigger for biological growth. Monitoring tidal nutrient fluxes and their impact on marine life is vital in maintaining the health of the bay."

Samples for nutrient analyses are collected on a monthly basis as part of ongoing Liverpool Bay coastal research. Together with salinity and temperature, nutrient data will be used in a series of complex mathematical models that simulate the tides and river inputs in the eastern Irish Sea.

Jonathan Sharples, Head of the Coastal Observatory in Liverpool Bay, said: "This is a great opportunity for the Proudman Oceanographic Laboratory to collaborate with the university and the local community and help to keep the Mersey in good health. The nutrient analyser will be an invaluable research and teaching tool for University students and will allow them to experience equipment that is used in the marine industry."