(Canada) Photo-oxidation of Dissolved Organic Carbon: Studies from the Rio Negro

Abstract

Palestrante: Prof. Dra. Ora Johannsson.

Instituição: University of British Columbia (Vancouver, Canada).

Resumo da palestra: Dissolved organic compounds play important roles both in the ecology of aquatic systems and in the physiology of organisms at low pH. Studies on the Rio Negro have been important in exploring these roles. Pysiological/toxicological experiments in fish have revealed the protective nature of DOC at low pH, first, against certain toxic metals, and secondly, for iono-regulation. Studies on the degradation of DOC, have revealed how patterns of degradation are maintained in the changing light field through the upper portion of the water column, the importance of oxygen and quality of light, and the significance of photo-oxidation in black tropical rivers to the return of carbon dioxide to the atmosphere.