We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
From heterotrophy to autotrophy: a freshwater estuarine ecosystem recovering from hypereutrophication.
- Authors
Cox, T. J. S.; Maris, T.; Soetaert, K.; Conley, D. J.; Van Damme, S.; Meire, P.; Middelburg, J. J.; Vos, M.; Struyf, E.
- Abstract
Increased organic matter and nutrient loads have induced major changes in aquatic systems, including hypoxia and algal blooms. In enclosed ecosystems these changes were often not gradual due to non-linear mechanisms. Here we report a 40 year record of eutrophication and hypoxia on an estuarine ecosystem and its recovery from hypereutrophication. We observe a paradoxical increase in chlorophyll a concentrations with decreasing nutrient inputs, and we hypothesise that algal growth was inhibited due to hypereutrophication, either by elevated ammonium concentrations, severe hypoxia or the production of harmful substances in such a reduced environment. We study the dynamics of a simple but realistic mathematical model, incorporating the assumption of algal growth inhibition. It shows an autotrophic equilibrium with low ammonia inputs, and a heterotrophic equilibrium with high ammonia inputs. At intermediate ammonia inputs it displays two alternative stable states. We conclude that the recovery of hypereutrophic riverine/estuarine systems can exhibit threshold-like behaviour.
- Subjects
ESTUARINE ecology; AUTOTROPHIC bacteria; HYPOXEMIA; HETEROTROPHIC bacteria; BIOTIC communities; ALGAL blooms
- Publication
Biogeosciences Discussions, 2009, Vol 6, Issue 3, p5431
- ISSN
1810-6277
- Publication type
Article
- DOI
10.5194/bgd-6-5431-2009