Reference : Field measurements of inorganic nitrogen uptake by epiflora components of the seagrass P...
Scientific journals : Article
Life sciences : Aquatic sciences & oceanology
Life sciences : Phytobiology (plant sciences, forestry, mycology...)
http://hdl.handle.net/2268/2484
Field measurements of inorganic nitrogen uptake by epiflora components of the seagrass Posidonia oceanica (Monocotyledons, Posidoniaceae)
English
Lepoint, Gilles mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Océanologie >]
Jacquemart, Julien [Université de Liège - ULG > Sciences de la Vie > Algologie, mycologie et systématique expérimentale > > >]
Bouquegneau, Jean-Marie mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Océanologie >]
Demoulin, Vincent mailto [Université de Liège - ULg > Département des sciences de la vie > Algologie, mycologie et systématique expérimentale >]
Gobert, Sylvie mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Océanologie >]
Apr-2007
Journal of Phycology
Blackwell Publishing
43
2
208-218
Yes (verified by ORBi)
International
0022-3646
Oxford
[en] N-15 tracer ; corallines ; eutrophication ; Mediterranean sea ; nitrogen ; seagrass ; stable isotopes
[en] Crustose corallines, crustose and erect brown algae, and sessile animals are major components of the epiphytic community of the Mediterranean seagrass Posidonia oceanica (L.) Delile. Production, biomass, and specific composition of this epiphyte-seagrass association are impacted by anthropogenic increase of nutrient load in this oligotrophic area. In this context, nitrogen uptake by P. oceanica and its epiflora was measured using the isotope N-15 at a 10 m depth in the Revellata Bay (Corsica, Mediterranean Sea). Epiflora components showed various seasonal patterns of biomass and abundance. The epiphytic brown algae appeared at the end of spring, later than the crustose corallines, and after the nitrate peak in the bay. Because of their later development in the season, epiphytic brown algae mostly rely on ammonium for their N needs. We hypothesize that the temporal succession of epiphytic organisms plays a crucial role in the N dynamics of this community under natural conditions. The epiphytic brown algae, which have a growth rate one order of magnitude greater than that of crustose corallines, showed lower N-uptake rates. The greater N-uptake rates of crustose corallines probably reflect the greater N requirements (i.e., lower C/N ratios) of red algae. We determined that the epiflora incorporated ammonium and nitrate more rapidly than their host. Nevertheless, when biomass was taken into account, P. oceanica was the most important contributor to N uptake from the water column by benthic macrophytes in this seagrass bed.
Centre Interfacultaire de Recherches en Océanologie - MARE
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS
Researchers
http://hdl.handle.net/2268/2484
http://www3.interscience.wiley.com/journal/118502442/abstract?CRETRY=1&SRETRY=0
The definitive version is available at www.blackwell-synergy.com

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