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Thursday, May 29, 2008 - 11:15 AM
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Stream variability in retention of multiple nutrients and metabolism along an altitudinal gradient
Eugènia Martí1, Paula Fonollà1, Francesc Sabater2, Daniel von Schiller1, Alba Argerich2, Miquel Ribot1, and Joan L. Riera2. (1) Limnology Group, Centre d'Estudis Avançats de Blanes (CSIC), Accés a la Cala Sant Francesc 14, Blanes (Girona), 17300, Spain, (2) Departament d'Ecologia, Universitat de Barcelona, Av. Diagonal 645, Barcelona, 08028, Spain
Mountain regions may be particularly vulnerable to climate change, which may influence biogeochemical responses in stream ecosystems. We examined the variability in stream biogeochemical responses along an altitudinal gradient associated to differences in microclimatic conditions to elucidate the influence of changes in environmental factors along this gradient. The study was done in 14 streams located in the Central Pyrenees (NE Iberian Peninsula) draining calcareous catchments that cover an altitudinal range from 2100 to 700 m a.s.l. In these streams we measured nutrient retention metrics of multiple nutrients (phosphate, ammonium, nitrate, acetate and glycine), whole stream metabolism and several physical, chemical and ecological parameters. To address our objective we took a multiparametric approach by using a Redundancy Analysis (RDA) with variance partitioning. We found that retention of organic forms of nutrients (i.e., glycine and acetate) showed a higher variability among streams than retention of inorganic forms of nutrients. Results also indicated that among-stream variability in gross primary production was higher than variability in ecosystem respiration. Finally, RDA results indicated that overall variability in retention of multiple nutrients along the altitudinal gradient was mostly dictated by the interplay between hydromorphological and ecological factors, accounting for more than half of the total variance.
Web Page: climate change, nutrient retention, metabolism