Back to Search Start Over

Salps in the Lazarev Sea, Southern Ocean: I. Feeding dynamics

Authors :
Brian P. V. Hunt
Ulrich Bathmann
Evgeny A. Pakhomov
Wilhelm Hagen
Lena von Harbou
Corinna Dubischar
Source :
Marine Biology. 158:2009-2026
Publication Year :
2011
Publisher :
Springer Science and Business Media LLC, 2011.

Abstract

Feeding dynamics of the Antarctic salps Ihlea racovitzai and Salpa thompsoni were studied in the Lazarev Sea in fall 2004, summer 2005–2006 and winter 2006. Pigment concentrations in the guts of both species were positively correlated with ambient surface chlorophyll a (chl a). No evidence was found for salp clogging even at dense surface concentrations of up to 7 μg chl a L−1. However, gut pigment concentrations had a lower range than ambient pigment concentrations, suggesting that salps increased retention times of ingested material in low-food environments. For medium-sized I. racovitzai and S. thompsoni, estimated individual daily rations reached 7–10 and >100% of body carbon in winter and summer, respectively. Daily respiratory needs of I. racovitzai and S. thompsoni accounted for 28 and 22% of daily carbon assimilation based on pigment ingestion rates in winter, and for 2 and 1% in summer, respectively. The grazing impact of the salp populations on the phytoplankton standing stock was negligible during all seasons due to generally low salp densities. Fatty acid trophic biomarkers in the salps suggest high year-round contributions of flagellates and modest contributions of diatoms to the salp’s diet. These markers showed low seasonal variability for I. racovitzai. The more pronounced seasonality of trophic markers in S. thompsoni were likely related to their generally deeper residence depth in winter linked to a seasonal alternation of sexual and asexual generations.

Details

ISSN :
14321793 and 00253162
Volume :
158
Database :
OpenAIRE
Journal :
Marine Biology
Accession number :
edsair.doi...........f4eeff9724b708d48e9ec9542a477f82
Full Text :
https://doi.org/10.1007/s00227-011-1709-4