2008/03/01 by Helle Ploug, Morten Hvitfeldt Iversen, Marja Koski +1 · 6 citations
Earth and Planetary Sciences · Environmental Science · #Marine and coastal ecosystems #Marine Biology and Ecology Research #Marine and fisheries research
paper · pdf · doi:10.4319/lo.2008.53.2.0469
openalex publication_date 2008/03/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/27
Production, oxygen uptake, and sinking velocity of copepod fecal pellets egested by Temora longicornis were measured using a nanoflagellate ( Rhodomonas sp.), a diatom ( Thalassiosira weissflogii ), or a coccolithophorid ( Emiliania huxleyi ) as food sources. Fecal pellet production varied between 0.8 pellets ind −1 h −1 and 3.8 pellets ind −1 h −1 and was significantly higher with T. weissflogii than with the other food sources. Average pellet size varied between 2.2 ×10 5 µm 3 and 10.0 ×10 5 µm 3 . Using an oxygen microsensor, small‐scale oxygen fluxes and microbial respiration rates were measured directly with a spatial resolution of 2 mm at the interface of copepod fecal pellets and the surrounding water. Averaged volume‐specific respiration rates were 4.12 fmol O 2 µm −3 d −1 , 2.86 fmol O 2 µm −3 d −1 , and 0.73 fmol O 2 µm −3 d −1 in pellets produced on Rhodomonas sp., T. weissflogii , and E. huxleyi , respectively. The average carbon‐specific respiration rate was 0.15 d −1 independent on diet (range: 0.08‐0.21 d −1 ). Because of ballasting of opal and calcite, sinking velocities were significantly higher for pellets produced on T. weissflogii (322 ± 169 m d −1 ) and E. huxleyi (200 ± 93 m d −1 ) than on Rhodomonas sp. (35 ± 29 m d −1 ). Preservation of carbon was estimated to be approximately 10‐fold higher in fecal pellets produced when T. longicornis was fed E. huxleyi or T. weissflogii rather than Rhodomonas sp. Our study directly demonstrates that ballast increases the sinking rate of freshly‐produced copepod fecal pellets but does not protect them from decomposition.