IMIS | Vlaams Instituut voor de Zee
 

Vlaams Instituut voor de Zee

Platform voor marien onderzoek

IMIS

Publicaties | Instituten | Personen | Datasets | Projecten | Kaarten
[ meld een fout in dit record ]mandje (0): toevoegen | toon Print deze pagina

A regime shift in a freshwater estuarine ecosystem recovering from hypereutrophication?
Cox, T.; Maris, T.; Soetaert, K.; Conley, D.; Van Damme, S.; Meire, P.; Struyf, E. (2009). A regime shift in a freshwater estuarine ecosystem recovering from hypereutrophication?, in: ASLO Aquatic Sciences Meeting 2009: A Cruise Through Nice Waters, 25-30 January 2009, Nice, France. pp. 56
In: (2009). ASLO Aquatic Sciences Meeting 2009: A Cruise Through Nice Waters, 25-30 January 2009, Nice, France. ASLO: Texas. 320 pp., meer

Beschikbaar in  Auteurs 
Documenttype: Samenvatting

Auteurs  Top 
  • Cox, T., meer
  • Maris, T., meer
  • Soetaert, K., meer
  • Conley, D.

Abstract
    After decades of hypereutrophication, with strong hypoxia and elevated ammonia concentrations, water quality in the freshwater part of the Schelde estuary changed rapidly. Average May-Sep oxygen concentrations more than quintupled, from 8% of saturation (1996) to 51% (2007). Ammonium concentrations decreased from a 296 µM May to Sep average (1996) to 16 µM (2007). Average May-Sep chlorophyll a concentrations increased from 15 µg/l (1996) to 178 µg/l (2007). From 2006 oversaturated oxygen concentrations are occasionally observed, caused by algal primary production. We hypothesise that inhibition of primary production and algal growth due to anoxia and/or ammonia toxicity prevented the build-up of algal biomass until a decade ago. We study the steady states and dynamics of a simple mathematical model, including this algal growth inhibition. It displays a regime shift from a heterotroph state to an autotroph state, when ammonia load is reduced below a threshold. At intermediate loads it predicts fluctuations in oxygen concentration in response to discharge peaks. Data and model results are consistent, and thus indicate a possible regime shift from heterotrophy to autotrophy in this ecosystem.

Alle informatie in het Integrated Marine Information System (IMIS) valt onder het VLIZ Privacy beleid Top | Auteurs