Dissolved organic matter (DOM) variations assessed in contrasting streams in the Pampas and Patagonian regions (Argentina)

GARCÍA, R. D.; MESSETTA, M. L; FEIJOO, C.; GARCÍA P.E.

MARINE AND FRESHWATER RESEARCH

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2018

1323-1650

Dissolved organic matter (DOM) is the major source of carbon (C) in aquatic environments and may be derived from allochthonous and/or autochthonous sources. This study presents the first DOM characterization in streams from two contrasting Argentinean regions (the Pampas and Patagonia). We found that dissolved organic carbon (DOC) concentrations and absorption coefficients (a254 and a350) were higher in Pampean than in Patagonian streams. DOM from streams in both regions contained compounds with high molecular weight and highly variable a350 DOC-1, this has been suggested that could be an indicator of lignin content. The characterization of DOM reflects the agricultural signal and the influence of autochthonous source in Pampean streams, while a more pristine condition with high input from terrestrial environments was recorded in Patagonian streams. No sign of DOM photodegradation was observed in either region. Fluorescence-based indexes suggest a more recent input of DOM in Pampean streams, while a highly humified component was recorded in Patagonian streams. The combined use of absorbance and fluorescent-based techniques was useful for understanding the DOM quantity and quality in these contrasting regions in Argentina.