English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/64054
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Influence of nutrients in the feeding ecology of seagrass (Posidonia oceanica L.) consumers: a stable isotopes approach

AuthorsPrado, Patricia ; Alcoverro, Teresa ; Romero, Javier
Issue DateApr-2010
CitationMarine Biology 157(4) : 715-724 (2010)
AbstractNitrogen inputs to coastal environments can considerably alter the abundance of primary producers. However, how herbivores modify their trophic signatures and adjust to changes in food resource conditions remains controversial. Here, we assess the effect of nutrient availability on the diet shifts of the two main Mediterranean herbivores, the Sparid fish Sarpa salpa L. and the sea urchin Paracentrotus lividus (Lmk.) that feed mostly on the seagrass Posidonia oceanica L. (Delile), epiphytes and benthic macroalgae. To do this, we (1) investigate the patterns of isotopic composition (d 13 C and d 15 N signatures) of the two herbivores and their potential food sources in three areas of contrasting nutrient conditions and, (2) we assess the diet shift along this nutrient gradient by estimating the isotopic nutrient enrichment (i.e., the contribution of d 13 C and d 15 N signatures in consumers’ tissues relative to potential food sources). Food web signatures of d 13 C were similar among the three study sites, and no patterns of d 13 C shift were observed in their diets. In contrast, there was a consistent increase in N contents and d 15 N along the nutrient gradient for all primary producers and their consumers. The rate of d 15 N enrichment was also clearly distinctive between the two herbivores: in P. lividus it increased by 61% along the nutrient gradient, while in S. salpa it remained constant. Our results suggest that sea urchins behave as facultative omnivores and feed on vegetable or mixed diets depending on the trophic status of the system. It is unclear, however, if this modification is behavioral or the consequence of mere changes in the availability of food items, as animal epiphytes (e.g., hydrozoans, bryozoans and ascidians) can also became more abundant on seagrass leaves under increased nutrient conditions. In contrast, adult fish appear to feed on vegetal material independent of nutrient availability in the ecosystem.
Description10 páginas,5 figuras, 3 tablas.
Publisher version (URL)http://dx.doi.org/10.1007/s00227-009-1355-2
Appears in Collections:(CEAB) Artículos
Files in This Item:
There are no files associated with this item.
Show full item record

Related articles:

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.