Prevalence of heterotrophy and atmospheric CO₂ emissions from aquatic ecosystems

• Published in: Ecosystems (New York) 2005-11, Vol.8 (7), p.862-870
• Main Authors: Duarte, C.M, Prairie, Y.T
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Aquatic ecosystems; aquatic habitat; Atmosphere; biodegradation; biogeochemical cycles; Biological and medical sciences; Biosphere; carbon dioxide; Carbon dioxide emissions; ecosystems; Freshwater ecosystems; Fundamental and applied biological sciences. Psychology; gas emissions; General aspects; heterotrophs; literature reviews; Marine ecosystems; Mesotrophic lakes; metabolism; Organic carbon; Organic matter; primary productivity; Synecology
• ISSN: 1432-9840; 1435-0629
• DOI: 10.1007/s10021-005-0177-4

Recent, parallel developments in the study of freshwater and marine ecosystems have provided evidence that net heterotrophic systems (those in which respiratory organic matter destruction exeeds photosynthetic production) are more prevalent than hitherto believed, including most rivers, oligo- to mesotrophic lakes and some oligotrophic regions of the ocean. In parallel, these aquatic ecosystems have been shown to act as CO^sub 2^ sources to the atmosphere, as expected from the heterotrophic nature of the communities they contain. The prevalence of net heterotrophic aquatic ecosystems indicates that they must receive significant inputs of organic carbon from adjacent ecosystems, assigning an important role to the lateral exchanges of carbon between land and aquatic ecosystems, between coastal and open ocean ecosystems, as well as internal redistribution within large or complex aquatic ecosystems in determining their metabolic status and the gaseous exchange with the atmosphere. The examination of the carbon budget of ecosystems requires, therefore, an integrative approach that accounts for exchanges between compartments often studied in isolation. These recent findings conform a new paradigm of the functioning of aquatic ecosystems, and the metabolic connectivity between ecosystems in the biosphere.[PUBLICATION ABSTRACT]