methodological approach to characterize the resilience of aquatic ecosystems with application to Lake Annecy, France

• Published in: Water resources research Vol. 43; no. 1
• Main Authors: Pinault, J.L, Berthier, F
• Format: Journal Article
• Language: English
• Published: 01.01.2007
• Subjects: autumn; benthic organisms; biodiversity; dissolved oxygen; dynamic models; ecosystems; energy transfer; evolution; hydrogeology; hydrologic models; lakes; methodology; minerals; organic matter; physicochemical properties; prediction; rivers; springs (water); stochastic processes; surface water; temperature; water flow; water quality; winter; France
• ISSN: 0043-1397; 1944-7973
• DOI: 10.1029/2006WR005125

1 We propose a methodological approach to characterize the resilience of aquatic ecosystems with respect to the evolution of environmental parameters as well as their aptitude to adapt to forcings. This method that is applied to Lake Annecy, France, proceeds in three stages. First, according to the depth, variations of physicochemical parameters versus time are separated into three components related to (1) energy transfer through the surface of the lake, (2) the flow of rivers and springs that feed the lake, and (3) long-term evolution of the benthic zone as a consequence of mineral and organic matter loads. Second, dynamics of the lake are deduced by analyzing the physicochemical parameter components related to the three boundary conditions. Third, a stochastic process associated with the transfer models aims to characterize the resilience of the lakes according to forcings. For Lake Annecy, whose dynamics are representative of oligotrophic stratified lakes controlled by decarbonation processes where turnover and mixing occurring once a year in winter, the major consequence is the impoverishment of dissolved oxygen in deep water in autumn due to a temperature increase of the surface water in summer. The simulation raises relevant questions about whether a connection exists between physicochemical parameters and global warming, which should not induce harmful consequences on water quality and biodiversity in deep water. This methodological approach is general since it does not use any physical conceptual model to predict the hydrosystem behavior but uses directly observed data.