Windermere’s secrets revealed by 65 years of lake monitoring

The Bowness meeting was hosted by the UK Centre for Ecology & Hydrology (CEH). Speakers from CEH, Universities, the Freshwater Biological Association and the Environment Agency covered topics including the history of the Windermere catchment, changes in water quality and ecology including the impact of invasive species, the bacterial health of the lake and future responses of Windermere to environmental change. Papers from the meeting will be published in a special issue of the scientific journal Freshwater Biology.

Dr Stephen Maberly from the Centre for Ecology & Hydrology, who leads the Windermere monitoring programme, said, "Windermere is probably the best studied lake in the world. The unique dataset collected over the last 65 years has been crucial in understanding a wide range of different issues, including the effect of nutrient enrichment on lake ecology, the impacts of invasive species, and the consequences of global climate change."

The English Lakes are among the best studied of any in the world with unrivalled detailed weekly or fortnightly records from 1945 onwards available. The Windermere data-series was begun by the Freshwater Biological Association but has been collected by scientists at the Centre for Ecology & Hydrology for the last two decades. Recent developments have included the installation of automatic water quality monitoring buoys.

The long-term records show that concentrations of phosphate have increased, that the amount of phytoplankton (the microscopic algae at the base of the food chain) has increased, and that the concentration of oxygen at the bottom of the lake in summer has become more depleted. Despite upgraded wastewater treatment works that remove some of the excess phosphorus, phytoplankton density has increased recently, possibly as a result of climate change and altered trophic-interactions.

Dr Maberly added, "Long-term monitoring is vital for understanding how lakes respond to environmental impacts and allow us to forecast how they may respond in future. The lessons learnt from Windermere have been vital in allowing the lakes' managers to improve the area and deal with specific issues, such as the conservation of rare species."