Organic matter dynamics in headwater forest streams of Northern Patagonia, Argentina

ALBARIÑO, R.J.; BURIA, L.M.; DÍAZ VILLANUEVA, V.

Valdivia, Chile

Workshop; Final international workshop in the framework of 10 years bilateral cooperation between Ghent University (Belgium) and Universidad Austral de Chile (Chile); 2008

Universidad Austral, Valdivia Chile

Streams are open and unidirectional systems where matter exchange with the surrounding landscape and exportation processes are important. Therefore, any mechanism delaying transportation rates will enhance biotic processes increasing in situ matter mineralization. Organic matter (OM) balances are defined by matter inputs and outputs within a system reach. Additionally, biotic components of the system are responsible for a major fraction of OM breakdown and nutrient cycling determining the transference of matter and energy up in the food web. The headwaters of large Patagonian rivers in Argentina discharge chemically diluted waters from forested Nothofagus catchments (pH circumneutral, conductivity ~50 µS cm-1, SRP ~2 µg L-1, NO3 ~15 µg L-1). Those small streams run through deciduous or mixed primary forests. The bulk of leaf litter enters in late summer-autumn (60-120 g m-2 mo-1) and is highly characterized by species with intermediate to slow decaying rates (k