CHARACTERIZATION OF DISSOLVED ORGANIC MATTER FROM LEACHATES OF AQUATIC MACROPHYTES AND DETRITUS OF THE SURROUNDING VEGETATION OF A COASTAL LAGOON

摘要

Coastal lagoons are characterized by large coastal regions widely colonized by aquatic macrophytes(Esteves,1998).Aquatic macrophytes play a key role in the metabolism of these ecosystems in regard to the stock and cycling of nutrients.The surrounding terrestrial vegetation(restinga)also represents a major detritus source for these lagoons.Decomposition transforms particulate organic matter into smaller molecules,through processes like leaching.The leaching process is more intense in the beginning of decomposition,releasing dissolved organic matter(DOM)and nutrients.The leached compounds can be classified as labile-e.g.carbohydrates,proteins,aminoacids and other low molecular weight compounds-or refractory-mainly humic substances(HS).HS are a major source of DOM in aquatic ecosystems,configuring a yellow to brown color to the water.