Differential element assimilation by sea urchins Paracentrotus lividus in seagrass beds: implications for trophic interactions
2006; Inter-Research; Volume: 306; Linguagem: Inglês
10.3354/meps306125
ISSN1616-1599
AutoresFiona Tomàs, D Álvarez-Cascos, Xavier Turón, Javier Romero,
Tópico(s)Marine Biology and Ecology Research
ResumoMEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 306:125-131 (2006) - doi:10.3354/meps306125 Differential element assimilation by sea urchins Paracentrotus lividus in seagrass beds: implications for trophic interactions F. Tomas1,3,*, D. Álvarez-Cascos1, X. Turon2, J. Romero1 1Departament d'Ecologia, and 2Departament de Biologia Animal (Invertebrats), Universitat de Barcelona, Avenida Diagonal 645, 08028 Barcelona, Spain3Present address: Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, California 92093-0202, USA *Email: ftomasnash@ucsd.edu ABSTRACT: Despite increasing evidence that herbivory in seagrass systems is more important than previously considered, many factors regulating seagrass herbivory still need to be elucidated. In this study we evaluate the importance of epiphytes and seagrass blades in sea urchin nutrition using a multiple stable-isotope approach. Our aim is to contribute to the understanding of plant–herbivore interactions in seagrass beds. Stable-isotope ratios of carbon, nitrogen and sulphur of the sea urchin Paracentrotus lividus (Lamarck) were measured and compared to those of the potential food sources (i.e. the seagrass Posidonia oceanica [L.] Delile and its epiphytes) in a temperate seagrass meadow. Epiphytes and seagrass leaves had distinct δ13C (–18.7 vs. –12.8‰, respectively) and δ15N values (+6.4 vs. +3.6‰, respectively), while values for δ34S were closer (+19.4 vs. +17.0‰, respectively). Data from δ13C and δ34S indicated that both food sources contributed in approximately equal proportions (50%) to the bulk organic matter assimilated by Paracentrotus lividus, whereas δ15N measurements showed that approximately 90% of the nitrogen assimilated by the sea urchin is provided by epiphytes. Given the generally low nutritional quality of P. oceanica leaves, the data obtained suggest that epiphyte nitrogen is crucial in regulating the trophic relationships between the herbivore and the seagrass. Thus in P. oceanica meadows, epiphytes, particularly through nitrogen contribution, appear to be an essential component of the diet of important herbivores such as sea urchins. KEY WORDS: Plant–herbivore interactions · Epiphytes · Stable isotopes · Nitrogen · Food quality · Mediterranean · Posidonia oceanica Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 306. Online publication date: January 11, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.
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