Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Seasonality, littoral versus pelagic carbon sources, and stepwise N-15-enrichment of pelagic food web in a deep subalpine lake: the role of planktivorous fish |
| Abstract | While the role of littoral food sources in shallow lakes has been widely investigated, uncertainties still exist about the relevance of such sources for deep lakes. Here we report quantitative estimates for the contribution of littoral versus pelagic sources in supporting the three most important planktivorous fish of a deep, large, subalpine lake in Italy. Contributions of pelagic (p) and littoral (q) signatures of delta C-13 and delta N-15 stable isotopes were detected in fish muscular tissue by applying a dynamic baseline mixing model. This model integrates tissue-specific metabolic turnover (m) and fish growth (k) rates over baselines delta C-13 seasonality. Annual fluctuations for both pelagic and littoral baselines were not negligible (Delta C = 10% and 8%, respectively). We calculated that they could not be ignored, since contributions of pelagic and littoral signatures would be largely underestimated (up to 30% p and 13% q for whitefish (Coregonus lavaretus) and roach (Rutilus rutilus), respectively). When fish relied upon pelagic consumers, stepwise N-15-enrichment (E) of pelagic preys linearly decreased with prey-size-specific predation pressure. Therefore, longer food webs would be proportionally less stepwise N-15-enriched than shorter ones. |
| Source | Canadian journal of fisheries and aquatic sciences (Print) 71 (3), pp. 436–446 |
| Keywords | Stable isotope analysisSeasonalityPlanktivorus fish |
| Journal | Canadian journal of fisheries and aquatic sciences (Print) |
| Editor | National Research Council Canada., Ottawa, Canada |
| Year | 2014 |
| Type | Articolo in rivista |
| DOI | 10.1139/cjfas-2013-0178 |
| Authors | Anna Visconti; Pietro Volta; Amedeo Fadda; Antonio Di Guardo; Marina Manca |
| Text | 328856 2014 10.1139/cjfas 2013 0178 ISI Web of Science WOS 000332461000011 Scopus 2 s2.0 84896840408 Stable isotope analysis Seasonality Planktivorus fish Seasonality, littoral versus pelagic carbon sources, and stepwise N 15 enrichment of pelagic food web in a deep subalpine lake the role of planktivorous fish Anna Visconti; Pietro Volta; Amedeo Fadda; Antonio Di Guardo; Marina Manca CNR ISE; University of Insubria While the role of littoral food sources in shallow lakes has been widely investigated, uncertainties still exist about the relevance of such sources for deep lakes. Here we report quantitative estimates for the contribution of littoral versus pelagic sources in supporting the three most important planktivorous fish of a deep, large, subalpine lake in Italy. Contributions of pelagic p and littoral q signatures of delta C 13 and delta N 15 stable isotopes were detected in fish muscular tissue by applying a dynamic baseline mixing model. This model integrates tissue specific metabolic turnover m and fish growth k rates over baselines delta C 13 seasonality. Annual fluctuations for both pelagic and littoral baselines were not negligible Delta C = 10% and 8%, respectively . We calculated that they could not be ignored, since contributions of pelagic and littoral signatures would be largely underestimated up to 30% p and 13% q for whitefish Coregonus lavaretus and roach Rutilus rutilus , respectively . When fish relied upon pelagic consumers, stepwise N 15 enrichment E of pelagic preys linearly decreased with prey size specific predation pressure. Therefore, longer food webs would be proportionally less stepwise N 15 enriched than shorter ones. Si le role des sources de nourritures littorales dans les lacs peu profonds a fait l objet de nombreuses etudes, des incertitudes persistent quant a` la pertinence de ces sources en ce qui concerne les lacs profonds. Nous rendons compte d estimations quantitatives des contributions de sources littorales et pelagiques aux regimes alimentaires des trois plus importants poissons planctonivores d un grand lac subalpin profond en Italie. Des contributions de signatures d isotopes stables 13C et 15N pelagiques p et littorales q ont ete detectees dans les tissus musculaires des poissons en appliquant un modele demelange integrant des conditions de base dynamiques. Ce modele integre des taux de renouvellement metabolique m propres aux tissus et de croissance des poissons k a` la saisonnalite des signatures de 13C de base. Les fluctuations annuelles des conditions de base tant pelagiques que littorales n etaient pas negligeables C = 10 et 8 , respectivement . Nous avons determine que ne pas tenir compte de ces fluctuations entrainerait une forte sous estimation des contributions des signatures pelagiques et littorales jusqu a` 30 % du p et 13 % du q pour les coregones Coregonus lavaretus et les gardons Rutilus rutilus , respectivement . Dans les cas ou les poissons dependaient de consommateurs pelagiques, l enrichissement sequentiel en 15N E des proies pelagiques diminuait de maniere lineaire parallelement a` la pression de predation pour la taille de proies concernee. Les longs reseaux trophiques seraient donc proportionnellement moins enrichis sequentiellement en 15N que les reseaux plus courts. 71 Published version Articolo 2014_Can_J_Fish_Aquat_Sci_71_436_446.pdf Articolo in rivista National Research Council Canada. 0706 652X Canadian journal of fisheries and aquatic sciences Print Canadian journal of fisheries and aquatic sciences Print Can. j. fish. aquat. sci. Print Canadian journal of fisheries and aquatic sciences. Print Journal canadien des sciences halieutiques et aquatiques Print pietro.volta VOLTA PIETRO marinamarcella.manca MANCA MARINA MARCELLA TA.P04.016.004 Ecologia teorica e applicata degli ecosistemi acquatici |