Electronic Precinct - January 1998

Global climate change and the restoration of shallow lakes

The School of Biological Sciences, at The University of Liverpool is centrally involved in two major projects concerned with the effects of global climate change on shallow freshwater systems.

Shallow lakes, dominated by water plants such as lilies and pondweeds are richly diverse habitats, valuable for fisheries in wetland and bird conservation. Unfortunately many have been damaged, especially by impacts such as nutrient pollution and stocking with exotic fish, like common carp. Many no w have algal-dominated waters of low diversity, amenity and conservation value. Research over the past two decades has led to understanding of the mechanics now affecting how plant communities might be resorted to such lakes. However many of these mechanisms are influenced by temperature. As a resu lt of human activities changing the composition of the atmosphere, the temperature in Europe is predicted to rise by 2-3°C by early next century. To cope with this we need to know how important ecological systems, like freshwaters, will react.

The first of the projects, funded by the Natural Environment Research Council, tackles the problem of how increased temperature will affect shallow lake ecosystem functioning by a direct experiment. The School of Biological Sciences has fifty large tanks, at the University's Botanic Gardens at Ness . In these tanks an aquatic ecosystem will be established. The tanks will be provided with insulation and heaters so that one group can be kept at ambient temperature, another heated to 3°C above ambient year round, and a third heated in summer only to 3°C above ambient. A set of nutrient addition (eutrophication) treatments will be superimposed and the combined effects of nutrient addition and heating followed continuously over two years. All aspects of the system from water chemistry to fish population dynamics will be followed and considerable insight into the likely future effects of glo bal warming on an important ecosystem type will by gleaned. Collaborating on this project will be Drs David Atkinson, Ian Harvey, John Eaton and Professor Brian Moss.

The second, funded through the European Community Environment and Climate Programme, involves research groups in Finland, Sweden, and Spain, as well as the School of Biological Sciences, through which Professor Brian Moss co-ordinates the whole project. The project will conduct the same experiment along a climate gradient represented by the participating countries. The experiment will use thirty-six mesocosms, containers which isolate a part of the lake littoral community, in each country to investigate the effects of adding combinations of nutrients and a fish, roach, to a submerged plant c ommunity, producing a unique data set with a rare degree of international co-operation. The project will also allow continuation of long-term monitoring of whole-lake restoration experiments in each country and detailed studies on processes important in the stabilisation and functioning of shallow lake ecosystems. In the UK, work will be concentrated on a group of lakes linked with Rostherne Mere in North Cheshire.