MEASUREMENT OF NUTRIENT SPIRALING DURING A PERIOD OF CONTINUOUS SURFACE FLOW IN A MEDITERRANEAN TEMPORARY STREAM (ARROYO DE LA MONTESINA, SPAIN)

Uptake rate of calcium, potassium, nitrate-N and phosphorus were measu red in a second order Mediterranean temporary stream, in February and March 1992. This study analysed a period of continuous surface flow be tween two hydrologic disturbance events(flood and drought) of an annua l hydrological cycle (1991-92). The lowest values of uptake length wer e recorded for nitrate-N in February 92 and calcium in March 92. Nitra te had the highest uptake rate in both release performances, and potas sium showed the lowest uptake rate values. The increase of calcium and nitrate uptake rate between February 92 and March 92 suggested a high er ecosystem efficiency in nutrient retention with a higher temperatur e and light intensity and slower water velocity, discharge and water d epth. These results obtained were similar to those reported in permane nt streams, indicating that in periods of continuous surface flow (wit hout extreme hydrologic disturbance), abiotic factors can influence nu trient retention in temporary streams.