HR: 09:00h
AN: NB41C-03    [Abstracts]
TI: A Stoichiometric Approach to Nutrient Retention in Stream Ecosystems
AU: * Marti, E
EM: eugenia@ceab.csic.es
AF: Centre d'Estudis Avancats d Blanes (CSIC), Acces a la Cala St. Francesc, 14, Blanes, 17300 Spain
AU: Sabater, F
EM: fsabater@ub.edu
AF: Departament d'Ecologia, Univ de Barcelona, Av. Diagonal, 645, Barcelona, 08028 Spain
AU: Battin, T J
EM: tomba@pflaphy.pph.univie.ac.at
AF: Dept.of Freshwater Ecology, Univ. of Vienna, Althanstrasse 14,, Vienna, 1090 Austria
AU: Gafny, S
EM: gafny@post.tau.ac.il
AF: Institute for Nature Conservation Research, Ramat Aviv, Tel Aviv, 69978 Israel
AU: Guilherme, P
EM: png@uevora.pt
AF: Centro de Ecologia Aplicada, Universidade de Evora, Largo dos Colegiais 2,, Evora, 7002-554 Portugal
AU: Pusch, M
EM: pusch@igb-berlin.de
AF: Institut f�r Gew„sser”kologie und Binnenfischerei, M�ggelseedamm 310, Berlin, 12587 Germany
AU: Sanchez-Perez, J M
EM: sanchez@ecolog.cnrs.fr
AF: Centre d'Ecologie des SystŠmes Aquatiques Continentaux - UMR C5576 - CNRS - Universit‚ Paul Sabatier, Rue Jeanne Marvig 29, Toulouse, 31055 France
AU: Solimini, A
EM: angelo.solimini@jrc.it
AF: Dipartamento di Biologia, Universit  di Roma "Tor Vergata", Via della Ricerca Scientifica, Roma, 00133 Italy
AU: Voreadou, C
EM: voreadou@nhmc.uoc.gr
AF: Natural History Museum of Crete, University of Crete, Knossou Avenue, Heraklion, 714 09 Greece
AU: Riera, J L
EM: jlriera@ub.edu
AF: Departament d'Ecologia, Univ de Barcelona, Av. Diagonal, 645, Barcelona, 08028 Spain
AB: We examined patterns of variability in stream retention response among nutrients based on results from multiple nutrient additions conducted in 11 European streams covering a wide range of environmental conditions. Based on previous observations, we argued that streams were not equally efficient at retaining different nutrients (i.e., N and P) or different ionic forms of the same element (i.e., NO3 and NH4) and generally exhibited higher efficiency for the nutrient or ion that was available in lower proportion. In this study we focussed on mass transfer coefficients for NH4, NO3, and PO4 (i.e., stream nutrient demand, Vf in m/s) as the most appropriate stream retention metric for comparing among and within streams, and among different nutrient forms. Stream nutrient demand was significantly different depending on the nutrient under consideration. Ammonium demand was the largest, followed by phosphate demand, and nitrate was the lowest. Using ratios between stream demand for pairs of nutrients (VfNO3:VfNH4, VfNH4:VfPO4, and VFNO3:VFPO4), we found consistent patterns with chemical parameters as well as with parameters of ecosystem metabolism which supported our hypothesis. Consideration of different nutrients and their relative proportions proved useful to expand our understanding of stream ecosystems in terms of nutrient dynamics.
UR: http://www.ceab.csic.es
DE: 0400 Biogeosciences
DE: 1030 Geochemical cycles (0330)
DE: 1803 Anthropogenic effects
DE: 1845 Limnology
DE: 4805 Biogeochemical cycles (1615)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly