Biogeochemical Output and Typology of Rivers Draining Patagonia's Atlantic Seaboard

Abstract

Abstract Between June 1995 and November 1998, eight Patagonian rivers were sampled for the suspended and dissolved loads delivered to the SW Atlantic. The most important rivers (Negro and Santa Cruz) jointly deliver ∼90% of the total Patagonian freshwater budget (∼60 km3 y−1). Of the total sediment load (∼1.7 1012 g y−1), 2.8% was accounted for by particulate organic carbon (POC), 0.9% by inorganic particulate carbon (PC), 0.7% by particulate nitrogen (PN), and 0.7% by particulate phosphorus (PP). The mean dissolved organic carbon (DOC) yield was ∼0.50 g m−2y−1, and POC ∼0.3 g m−2y−1. Nitrogen is the limiting nutrient in all rivers; the mean molecular C:N:P ratio is 37:1:1. POC:PN ratios (4.4–10) indicate an autochthonous origin for the organic matter in suspended particulate matter (TSS). Many factors, such as proglacial oligotrophic lakes, coal-bearing strata, wetlands, aridity, as well as various human impacts, suggest a complex typology. The analysis (Euclidean distance cluster analysis) of biogeochem...