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 (Articolo in rivista)

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Label
  • 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 (Articolo in rivista) (literal)
Anno
  • 2014-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1139/cjfas-2013-0178 (literal)
Alternative label
  • Anna Visconti; Pietro Volta; Amedeo Fadda; Antonio Di Guardo; Marina Manca (2014)
    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
    in Canadian journal of fisheries and aquatic sciences (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Anna Visconti; Pietro Volta; Amedeo Fadda; Antonio Di Guardo; Marina Manca (literal)
Pagina inizio
  • 436 (literal)
Pagina fine
  • 446 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 71 (literal)
Rivista
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali
  • 11 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo
  • 3 (literal)
Note
  • ISI Web of Science (WOS) (literal)
  • Scopu (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • CNR ISE; University of Insubria (literal)
Titolo
  • 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 (literal)
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. (literal)
  • Si le rôle des sources de nourritures littorales dans les lacs peu profonds a fait l'objet de nombreuses études, 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 pélagiques aux régimes 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) pélagiques (p) et littorales (q) ont été détectées dans les tissus musculaires des poissons en appliquant un modèle demélange intégrant des conditions de base dynamiques. Ce modèle intègre des taux de renouvellement métabolique (m) propres aux tissus et de croissance des poissons (k) a` la saisonnalité des signatures de ?13C de base. Les fluctuations annuelles des conditions de base tant pélagiques que littorales n'étaient pas négligeables (?C = 10 ? et 8 ?, respectivement). Nous avons déterminé que ne pas tenir compte de ces fluctuations entraînerait une forte sous-estimation des contributions des signatures pélagiques et littorales (jusqu'a` 30 % du p et 13 % du q pour les corégones (Coregonus lavaretus) et les gardons (Rutilus rutilus), respectivement). Dans les cas où les poissons dépendaient de consommateurs pélagiques, l'enrichissement séquentiel en 15N (E) des proies pélagiques diminuait de manière linéaire parallèlement a` la pression de prédation pour la taille de proies concernée. Les longs réseaux trophiques seraient donc proportionnellement moins enrichis séquentiellement en 15N que les réseaux plus courts. (literal)
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