Assessment of variations in dissolved organic matter in contrasting streams in the Pampas and Patagonian regions (Argentina)

GARCIA, R. D.; MESSETA, M. L. ; FEIJOÓ, C. ; GARCIA, PATRICIA ELIZABETH

MARINE AND FRESHWATER RESEARCH

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2019 vol. 70 p. 698 - 707

1323-1650

Dissolved organic matter (DOM) is the major source ofcarbon (C) in aquatic environments and may be derived from allochthonous and/orautochthonous sources. This study presents the first DOM characterization instreams from two contrasting Argentinean regions (the Pampas and Patagonia). Wefound that dissolved organic carbon (DOC) concentrations and absorptioncoefficients (a254 and a350) were higher in Pampean thanin Patagonian streams. DOM from streams in both regions contained compounds withhigh molecular weight and highly variable a350 DOC-1, thishas been suggested that could be an indicator of lignin content. Thecharacterization of DOM reflects the agricultural signal and the influence ofautochthonous source in Pampean streams, while a more pristine condition withhigh input from terrestrial environments was recorded in Patagonian streams. Nosign of DOM photodegradation was observed in either region. Fluorescence-basedindexes suggest a more recent input of DOM in Pampean streams, while a highlyhumified component was recorded in Patagonian streams. The combined use ofabsorbance and fluorescent-based techniques was useful for understanding theDOM quantity and quality in these contrasting regions in Argentina.