The Relationships Among Man's Activities in Watersheds and Estuaries: A Model of Runoff Effects on Patterns of Estuarine Community Metabolism

摘要: Activities of man in rivers and their watersheds have altered enormously the timing, magnitude, nature inputs materials to estuaries. Despite an awareness large-scale, long-term changes river-estuarine watersheds, we do not fully understand consequences estuarine ecosystems these activities. Deforestation, urbanization, agriculturalization changed timing material Conversion land from forest almost any other use promotes overland flow storm runoff; increases rate magnitude sediment, organic matter, inorganic nutrient export. It has been estimated that total carbon levels increased by a factor 3–5 over natural levels. Man’s activities also particulate relative dissolved export lability matter. Historically, streams had different features than they today. Two man’s pronounced effects on quality river water are channelization damming. Agricultural drainage systems, channelized deepened streams, leveeing prevention overbank flooding combined effect increasing amplitude runoff, sediment load, delivery downstream, decreasing riparian wetland productivity. Dams hand discharge patterns downstream transfer sediments, nutrients. Patterns community metabolism sensitive variations, watersheds. The autotrophic-heterotrophic estuary is determined three primary factors: ratio matter inputs, residence time, overall allochthonous inputs. A simulation model used explore spatial production respiration generalized system. Examined variations ratios nitrogen loading, time estuary, degradability Simulations suggest balance estuaries more loading loading. Water flocculation-sedimentation two physical factors most simulated