Trophic Relationships within Intertidal Communities of the Brittany Coasts: A Stable Carbon Isotope Analysis

• Published in: Journal of coastal research 1998-09, Vol.14 (4), p.1202-1212
• Main Authors: DAUBY, P, KHOMSI, A, BOUQUEGNEAU, J.-M
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Coastal ecology; Coasts; Diet; Ecological zones; Food webs; Fundamental and applied biological sciences. Psychology; Littoral ecosystems; Marine ecology; Marine ecosystems; Sea water ecosystems; Synecology; Wetland ecology
• ISSN: 0749-0208; 1551-5036

More than 100 species belonging to plant and animal taxa that are commonly observed in the intertidal zone were collected on both rocky and soft bottom shores of Brittany, France, to be analysed for their13C/12C ratio. Plant material displayed a wide range of δ13C values (from -12 to$-34\textperthousand$), with relatively distinct values among producer groups ($Chlorophyce\ae$, Fucales, Laminariales,$Rhodophyce\ae$, seagrasses, plankton), and among strata of intertidal zonation. Animal δ13C range was narrower (-15 to$-22\textperthousand$), and in general, values differed more between than within phyla or classes, according to the staple diet of organisms. A good correlation between the δ13C values of food and consumers was noted, together with a slight13C-enrichment ($\approx 1 \textperthousand$) with increasing trophic levels from suspension-feeders to predators. /// Plus de 100$esp\grave{e}ces$, appartenant aux embranchements$commun\acute{e}ment$ $rencontr\acute{e}s$dans la zone intertidale, ont$\acute{e}t\acute{e}$ $r\acute{e}colt\acute{e}s$sur les$c\hat{o}tes$tant rocheuses que sablonneuses de Bretagne, France, en vue de l analyse de leur rapport isotopique13C/12C. Le$mat\acute{e}riel$ $v\acute{e}g\acute{e}tal$montre une large gamme de δ13C (de$-12\grave{a}$ $-34\textperthousand$), avec, toutefois, des valeurs relativement bien distinctes pour les différents groupes de producteurs ($Chlorophyce\ae$, Fucales, Laminariales,$Rhodophyce\ae$,$phan\acute{e}rogames$, plancton), et, par là, pour les différentes strates de la zonation intertidale. La plage de δ13C des animaux est plus$\acute{e}troite$(de$-15 \grave{a}$ $-22\textperthousand$), et, de$fa\c{c}on$ $g\acute{e}n\acute{e}rale$, les valeurs different plus entre unites$syst\acute{e}matiques$qu au sein du même embranchement ou de la même classe, en relation avec le$r\acute{e}gime$de base des organismes. Une bonne correlation est$observ\acute{e}e$entre le δ13C de la nourriture et des consommateurs, ainsi qu un$l\acute{e}ger$bioenrichissement en$^{13}C\approx 1\textperthousand$) avec l accroissement du niveau trophique, des suspensivores aux$pr\acute{e}dateurs$.