HR: 1330h
AN: NB33L-04    [Abstracts]
TI: SRP Transport in the Salto River, Costa Rica: Long-term Monitoring and Short-term Experimental Approaches
AU: * Triska, F J
EM: fjtriska@usgs.gov
AF: US Geological Survey WRD, 345 Middlefield Rd., Menlo Park, CA 94025 United States
AU: Pringle, C M
EM: cpringle@uga.edu
AF: University of Georgia, Institute of Ecology, Athens, GA 30602 United States
AU: Duff, J H
EM: jhduff@usgs.gov
AF: US Geological Survey WRD, 345 Middlefield Rd., Menlo Park, CA 94025 United States
AU: Avanzino, R J
EM: avanzino@usgs.gov
AF: US Geological Survey WRD, 345 Middlefield Rd., Menlo Park, CA 94025 United States
AU: Ardon, M
EM: mardon@uga.edu
AF: University of Georgia, Institute of Ecology, Athens, GA 30602 United States
AB: Soluble reactive phosphorus (SRP) transport retention was determined since 1988 at 4 sites in three rain forest streams draining La Selva Biological Station, Costa Rica. SRP levels can be naturally high there due to regional geothermal groundwater discharge at ambient temperature. Mean SRP was 89±53ug/L for the Salto (1988-1996) compared to 21±39ug/L for a tributary Pantano (1988-1998) and 26±35ug/L in the nearby Sabalo. After 1997 Salto SRP was determined separately in upland (Upper Salto) and lowland forest (Lower Salto) reaches. Upper Salto SRP is low until enriched at the slope transition. There high SRP springs contribute approximately 36% of long term discharge and 85% of SRP load leaving the watershed. TP is negatively correlated to discharge in all streams. SRP is not correlated to discharge at low SRP sites, but negatively correlated to discharge in Lower Salto when data from 2 ENSO events (EL Nino Southern Oscillation) are removed. Short-term SPR conservative tracer addition experiments indicate high retention at all sites. Retention is dominated by sediment, as indicated by subsequent adsorption-desorption studies. Enhanced input to high SRP streams can affect biotic metabolism, litter decomposition and secondary production in these tropical environments.
DE: 1871 Surface water quality
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly