Ménard Frédéric, Benivary H. D., Bodin Nathalie, Coffineau N., Le Loc'h François, Mison T., Richard P., Potier Michel. (2014). Stable isotope patterns in micronekton from the Mozambique Channel. In :
Barlow R. (ed.), Marsac Francis (ed.), Ternon Jean-Francois (ed.), Roberts M. (ed.). The Mozambique channel : mesoscale dynamics and ecosystem responses. Deep-Sea Research Part II.Topical Studies in Oceanography, 100 (No spécial), p. 153-163. ISSN 0967-0645.
Titre du document
Stable isotope patterns in micronekton from the Mozambique Channel
Année de publication
2014
Auteurs
Ménard Frédéric, Benivary H. D., Bodin Nathalie, Coffineau N., Le Loc'h François, Mison T., Richard P., Potier Michel
In
Barlow R. (ed.), Marsac Francis (ed.), Ternon Jean-Francois (ed.), Roberts M. (ed.), The Mozambique channel : mesoscale dynamics and ecosystem responses
Source
Deep-Sea Research Part II.Topical Studies in Oceanography, 2014,
100 (No spécial), p. 153-163 ISSN 0967-0645
We measured the stable carbon (delta C-13) and nitrogen (delta N-15) isotopic composition of tissues of micronektonic organisms (fishes, squids, crustaceans and gelatinous organisms) collected in the Mozambique Channel during two scientific cruises in 2008 and 2009. The oceanic circulation in the Mozambique Channel is dominated by mesoscale cyclonic and anticyclonic eddies which play a key role in biological processes of less-productive deep-sea ecosystems. We investigated the potential impact of mesoscale features on the delta C-13 and delta N-15 values of 32 taxa of micronekton. Fishes, squids, crustaceans and gelatinous organisms encompassed a wide range of isotopic niches, with large overlaps among species. Our results showed that mesoscale features did not really influence the isotopic signatures of the sampled organisms, although cyclonic eddies can occasionally impact the nitrogen signatures of micronekton. We show that delta C-13 values were intermediate between standard offshore and nearshore signatures, suggesting that pelagic production in the Mozambique Channel could be partly supported by the transport and export of inorganic and organic particles from the Mozambican coast toward the offshore area. Trophic levels calculated from delta N-15 values ranged from 2.6 to 4.2, showing that micronekton taxa can be tertiary consumers in the Mozambique Channel. Our findings evidenced clusters of micronektonic organisms according to their delta N-15 or delta C-13 isotopic signatures, but variations in stable isotope values reflect a complex set of embedded processes linked to physical mesoscale dynamics (rotational dynamics of eddies) and basic biology and ecology of micronektonic organisms (vertical habitat, migration pattern, dietary habits, body length) that are discussed with regard to the stable isotope method based on time-integrated assimilated food.
Plan de classement
Ecologie, systèmes aquatiques [036]
Description Géographique
MOZAMBIQUE CANAL ; OCEAN INDIEN
Localisation
Fonds IRD [F B010061903]
Identifiant IRD
fdi:010061903
