Sediment-water nutrient fluxes: preliminary results of in situ measurements in Alfaques Bay, Ebro River Delta

摘要: Sediment-water exchanges of oxygen, ammonium, nitrate, total dissolved nitrogen, phosphate and phosphorus were measured by means an in situ incubator 7 1 volume 700 cm2 base area. The incubations lasted for three hours done over a whole season on different kinds sediments Alfaques Bay. We present some preliminary results on: i) methodological aspects, ii) spatial temporal variability fluxes, iii) estimates contribution benthic nutrient regeneration relative to loading the Oxygen uptake averaged 1700 mmo1 m-2 h-1 (range 200-3500); no differences found between sandy muddy sediments. release ammonia from sediment 70 was higher than ones. Very low null nitrate nitrite fluxes only small organic nitrogen detected. conclude that ammonium is major path regeneration. Some removed reactive (DRP) water released (DOP). Additional manipulative experiments revealed DRP under particular conditions (turbulence, anoxia). From these data, we estimate at least 50% requirements phytoplankton area may be supplied remineralization.