Abstract ID: 431

DEFORESTATION IMPACT ON DOC FLUXES IN CENTRAL AMAZONIA

Carbon transport in small streams is being considered and important source of carbon loss in terra firme environments, and plays an important role on the Amazon carbon cycle. The objective of this study was to analyze the influence of forest conversion to pasture on organic carbon fluxes. Continuous measurements of rainfall, discharge and DOC (S::can,Scan::lyser, Messetechnik GmbH, Austria) in a paired experimental micro-catchments, with forest and pasture vegetation, were used. For selected events, the fluxes of Dissolved Organic Carbon - DOC were analysed using two different time parameters: time to the peak of DOC and time of recession, defined as the time when the DOC fluxes return to values close to the beginning of the event. Results showed that land use changes modified DOC fluxes, both in terms of the response time in their magnitude. In forested environments, time to the peak of DOC is dampened (4.9 ± 3.1 hs) compared to old pastures(2.6 ± 0.9 hs). The time of recession of carbon fluxes is also larger in Forest environments (33 ± 13.9 hs) compared to pasture micro-catchments. (16.8 ± 7.2 hs). Both the peak time of DOC (F = 7,996; p = 0,00770; N = 35) and the recession time (F = 19,538; p = 0,00009; N = 35) are statistically different for both land uses. As expected, land cover plays a fundamental role in small streams carbon transport. Carbon transport depend not only in the amount of carbon store in each environment, but also in the differences in water pathways which modify the response time and attenuation of carbon fluxes.

Session:  Carbon - Effects of land-cover/land-use change in carbon stocks.

Presentation Type:  Poster