Document: STE-3-59-112

Net carbon exchange from a tropical wet forest.

OBERBAUER, S.F.* ¹, H.W.LOESCHER ², D.B.CLARK ³ and D.A.CLARK ³

Florida International University, Miami, FL 33199 USA ¹
University of Florida, Gainesville, FL 32611 USA ²
University of Missouri, St. Louis, MO 63121 USA ³

Abstract:
Eddy covariance (EC) measurements of CO₂ were conducted in tropical lowland wet forest at the La Selva Biological Station in Costa Rica. The system was based on a closed-path infrared gas analyzer and sonic anemometer mounted on a 42 m tower. Prevailing winds at the site are easterly from the Caribbean with little anthropogenic influence. The tower footprint is primary upland forest. We estimated the annual net ecosystem exchange for 1999 based on EC and relationships between respiration and uptake rates. E.C. data were filtered for U* 0.15 m s^-1 and no rain events, so estimates are likely conservative for both uptake and respiration. Ecosystem-level respiration was found to have a Q-1 y^-1. The pattern of carbon uptake was strongly seasonal. Approximately 66% of the carbon was sequestered during the dry season. The results suggest that contrasting climatic factors control net carbon exchange during wet and dry seasons.

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This abstract is being presented at: 1:45 PM in session:
Oral Session #64: Remote Sensing.