Spatial and temporal variations of dissolved carbon at the riparian zone of a forest fragment in Rondônia, Brazil.
Leite, CENA/USP, firstname.lastname@example.org
Krusche, CENA/USP, email@example.com
Souza, UNIR, firstname.lastname@example.org
Cabianchi, UNIR, email@example.com
Nutrient dynamics in riparian zones play an important role in terrestrial and aquatic ecosystems coupling. With the expansion of deforestation in the Amazon, in the last decades several mosaics of degraded landscape have appeared, mainly in places where small segments of riparian zone used to form buffer zones between areas of varied land uses and the watercourses. Due to this new landscape framework, it’s essential to identify the main nutrient flowpaths within these systems. In this context, the main goal of this study is the quantification of carbon fluxes in a fragment of riparian zone of the Urupá River basin, Rondônia state. In order to achieve that, since December of 2005 we have been sampling biweekly the main flowpaths of this system: rain water, throughfall, litterfall, overland flow, soil solution, groundwater, and the main channel of the Urupá River. In all these samples, in addition to physical-chemical parameters (pH, temperature and electric conductivity) measured in the field, aliquots are taken for the analysis of Organic and Inorganic Dissolved Carbon (DOC and DIC) concentrations. The highest concentrations of DOC were found in overland flow (average = 555,44 mM (micromolar)) and throughfall (average = 474,86 mM (micromolar)), respectively. For DIC, the highest concentrations were observed in soil solution, mainly in the deepest lysimeter (100 cm), with an average of 430,22 mM (micromolar). These preliminary results indicate that the transport of C in solution may be an important pathway transferring this element from terrestrial to aquatic systems in this riparian fragment.
Keywords: Amazon, carbon, nutrient cycling, riparian.