Aquatic Sciences Meeting, Albuquerque 2001

CS37 Zooplankton

Date: Wednesday, February 14, 2001, Time: 11:30:00 AM

Location: Aztec

Stevens, C, J, Ocean Sciences Centre, Memorial Univ. of Newfoundland, St. John's, Canada, x79cjs@morgan.ucs.mun.ca

Deibel, D, , Ocean Sciences Centre, Memorial Univ., St. John's, Canada,

Parrish, C, C, Ocean Sciences Centre, Memorial Univ., St. John's, Canada,

DIFFERENCES IN LIPID-DERIVED INDICES OF OMNIVORY BETWEEN TWO SPECIES OF ARCTIC COPEPODS

Quantification of copepod diets is essential in understanding their role in marine food webs. We compared the lipid compositions of Calanus hyperboreus (stage V) and Metridia longa (females) sampled in fall 1999 in the North Water polynya (Northern Baffin Bay). As potential indices of herbivory, unsaturation coefficients (u.c.) were calculated as the proportion of total wax ester that was polyunsaturated. Over a broad range of conditions, u.c. estimates were higher for C. hyperboreus than for M. longa. Similarly, contributions of bacterial fatty acids (odd- numbered and branched) to total fatty acids, which may indicate ingestion of bacteria and/or bacterivorous protists, were higher in M. longa than in C. hyperboreus. Our results suggest that M. longa is more omnivorous than C. hyperboreus. Within each species, u.c. were higher in the surface layer than deeper in the water column. Spatial trends over a range of ca. 4 degrees latitude were also evident. Omnivory may thus vary locally with changing prey communities.

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Aquatic Sciences Meeting, Albuquerque 2001

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