Sediment-water nutrient fluxes: preliminary results of in situ measurements in Alfaques Bay, Ebro River Delta
Vidal, M.; Romero, J.; Camp, J. (1989). Sediment-water nutrient fluxes: preliminary results of in situ measurements in Alfaques Bay, Ebro River Delta, in: Ros, J.D. (Ed.) Topics in Marine Biology: Proceedings of the 22nd European Marine Biology Symposium, Barcelona, Spain, August 1987. Scientia Marina (Barcelona), 53(2-3): pp. 505-511
In: Ros, J.D. (Ed.) (1989). Topics in marine biology: Proceedings of the 22nd European Marine Biology Symposium, Barcelona, Spain, August 1987. European Marine Biology Symposia, 22. Scientia Marina (Barcelona), 53(2-3). 145-754 pp., meer
In: European Marine Biology Symposia., meer
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Documenttype: Congresbijdrage
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| Auteurs | | Top |
- Vidal, M.
- Romero, J.
- Camp, J.
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| Abstract |
Sediment-water exchanges of oxygen, ammonium, nitrate, total dissolved nitrogen, phosphate and total dissolved phosphorus were measured by means of an in situ incubator of 7 l volume and 700 cm² base area. The incubations lasted for three hours and were done over a whole season on different kinds of sediments in Alfaques Bay. We present some preliminary results on: i) methodological aspects, ii) spatial and temporal variability of fluxes, and iii) estimates of contribution of benthic nutrient regeneration relative to total nutrient loading of the Bay. Oxygen uptake averaged 1700 µmol m-2 h-1 (range 200-3500); no differences were found between sandy and muddy sediments. The release of ammonia from the sediment averaged 70 µmol m-2 h-1 and was higher in muddy sediments than in sandy ones. Very low to null nitrate and nitrite fluxes and only small fluxes of organic nitrogen were detected. We conclude that ammonium release from sediment is the major path of nitrogen regeneration. Some sediments removed dissolved reactive phosphorus (DRP) from the water and released dissolved organic phosphorus (DOP). Additional manipulative experiments revealed DRP release under particular conditions (turbulence, anoxia). From these data, we estimate that at least 50 % of the nitrogen requirements of phytoplankton in the area may be supplied by benthic remineralization. |
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