Monitoring the health of the River Mersey

POL's state-of-the-art nutrient analyser is being used by scientists from the University of Liverpool 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 the nutrient analyser 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 the 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.

POL's Dr 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."

The Proudman Oceanographic (POL) scientific research focuses on oceanography encompassing global sea-levels and geodesy, numerical modelling of continental shelf seas and coastal sediment processes. This research alongside activities of surveying, monitoring, data management and forecasting provides strategic support for the wider mission of the Natural Environment Research Council.

As a public funded body it is part of our remit to inform the public of the science and research undertaken at the laboratory. Attending events like the 'Ocean Awareness Weekend' at the Blue Planet Aquarium offers the opportunity for our scientists to meet members of the public and present the laboratory's work.

The Natural Environment Research Council is one of the UK's eight Research Councils. It uses a budget of about £ 350m a year to fund and carry out impartial scientific research in the sciences of the environment. NERC trains the next generation of independent environmental scientists. It is addressing some of the key questions facing mankind, such as global warming, renewable energy and sustainable economic development.