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Impact of climate change on carbon flux in freshwater ecosystems


The overall aim is to understand the impact of rising CO2 and temperature on the structure and dynamics of lake ecosystems.

This project will be the first undertaken where a rigorous understanding of the response of freshwater ecosystems to climate change is addressed in a holistic way, including response patterns at different functional levels integrated up to a manipulated ecosystem study. A model will be produced to improve generality and prediction capability of the effects of climatic change and for use as a tool for water managers Freshwaters are very comlex systems, whose functioning is controlled by feedback processes between physics, chemistry and biology. In order to assess the impact of climate change on freshwaters it is therefore necessary to understand the mechanisms of response at a physiological level and scale this up through community structure to an ecosystem level. In order to achieve this we have chosen a hierarchical approach culminating in ecosystem manipulation experiments to test the predictions gained at lover levels of study.

- Laboratory studies to determine the response of individual organisms or functional groups to changes in environmental variables. The responses measured will include photosynthesis, growth rate, metabolic rate, chemical composition and extent of acclimation.

- Field studies to assess the sensitivity of the different groups of primary producers, phytoplankton, submerged and emergent macrophytes, to increases in CO2 concentrations in lakes from a range of trophic types and varying in thei water hardness and hence background concentrations of inorganic carbon.
- Ecosystem manipulations to assess interactions between subprocesses and their effect on community structure and organic carbon flow and whole-system response to increased concentrations of CO2 and temperature. This will be performed at an artificial lake ecosystem where key environmental parameters can be manipulated.

- Modelling to incorporate the data obtained in a mathematical model. This will improve generality and provide a tool for prediction of effects of climatic changes and be of use to managers of water resources.
The expected achievements are to:

- Quantify the short- and long-term responses of primary-producers and decomposers to gain a better understanding of carbon-cycling and accumulation in response to climate change.

- Identify the main direction and underlying mechanisms driving changes in community structure and biodiversity.

- Identify the relationships and reciprocal interactions between the trophic levels and the pattern of lake ecosystem response.

- Increase knowledge of ecosystem stability and sensitivity to environmental change.

Funding Scheme

CSC - Cost-sharing contracts


51,Helsingoersgade 15
3400 Hilleroed

Participants (3)

International Institute for Infrastructural, Hydraulic and Environmental Engineering
75,Westvest 75
2601 Delft
United Kingdom
Far Sawrey The Ferry House
LA22 OLP Ambleside
73,Niemenkatu 73
15140 Lahti