Meeting Abstract
Stable isotopes have proven useful in demonstrating trophic relationships within food webs, including marine planktonic systems. The isotopic profiles of jellyfish in general are not well studied in the waters of Massachusetts. We determined the δ13C, δ15N and some δ34S values of Aurelia aurita collected from Salem Harbor, Massachusetts. Individuals were sectioned into the bell, oral arms, and tentacles to determine if fractionation of isotopes varies within the body. Subsamples had lipids extracted and were run in parallel with non-extracted samples from the same individuals and tissues. Stable isotope values for lipid-extracted samples did not differ from unextracted, so further analyses were performed on unextracted samples. δ13C values for oral arms and bell were -20.8‰ and -21.2‰, respectively. δ15N values were 9.9‰ and 11.6‰ for the same tissues. Values for all except bell δ15N differ significantly from those found for Aurelia sp. in the Gulf of Mexico (D’Ambra et al., 2014; δ13C: -18.8 and -18.3‰; δ15N: 12.0 and 11.5‰). These differences may reflect a more inshore site of collection for our samples, latitudinal or seasonal differences, or differences in trophic position. δ34S values are very enriched (20.7-28.9‰) suggesting a low trophic position for A. aurita in Massachusetts.
