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Depth-dependence in stable isotope ratio δ15N of benthic POM consumers: The role of particle dynamics and organism trophic guild
- Source :
-
Deep-Sea Research Part I, Oceanographic Research Papers . Jun2007, Vol. 54 Issue 6, p1015-1023. 9p. - Publication Year :
- 2007
-
Abstract
- Abstract: The stable nitrogen isotope ratio (δ15N) is an established indicator of trophic hierarchy in marine food-web studies. Most of these studies presume that spatial variation in the primary food source is negligible, although a water-depth-related increase in δ15N of particulate organic matter (POM) has been found in many systems. We used the high-Antarctic Weddell Sea shelf and slope ecosystem to test whether such a depth-related change in δ15N is reflected at higher trophic levels, i.e., benthic consumers of POM. In suspension feeders (SF) we found a significant increase in δ15N with water depth of up to 9.8‰, whereas in deposit feeders (DF) a depth effect was barely detectable. Particle-size preferences of the two feeding guilds combined with particle-size-dependent sinking velocities and biogeochemical reworking of POM are discussed as the major causes of these differences. It is essential to marine food-web studies to take into account the general depth effect on POM δ15N as well as potential feeding-guild-specific differences in the response of POM consumer tissue δ15N to avoid serious bias and misinterpretation of stable-isotope-based trophic information. [Copyright &y& Elsevier]
- Subjects :
- *STABLE isotopes
*NITROGEN
*FOOD chains
*BIOTIC communities
Subjects
Details
- Language :
- English
- ISSN :
- 09670637
- Volume :
- 54
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- Deep-Sea Research Part I, Oceanographic Research Papers
- Publication Type :
- Academic Journal
- Accession number :
- 25185322
- Full Text :
- https://doi.org/10.1016/j.dsr.2007.03.005