TY - JOUR
T1 - Production, oxygen respiration rates, and sinking velocity of copepod fecal pellets: Direct measurements of ballasting by opal and calcite
AU - Ploug, Helle
AU - Iverson, Morten Hvitfeldt
AU - Koski, Marja
AU - Buitenhuis, Erik Theodoor
PY - 2008
Y1 - 2008
N2 - 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 ind21 h21 and 3.8 pellets
ind21 h21 and was significantly higher with T. weissflogii than with the other food sources. Average pellet size
varied between 2.2 3105 mm3 and 10.0 3105 mm3. 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 O2 mm23 d21,
2.86 fmol O2 mm23 d21, and 0.73 fmol O2 mm23 d21 in pellets produced on Rhodomonas sp., T. weissflogii, and E.
huxleyi, respectively. The average carbon-specific respiration rate was 0.15 d21 independent on diet (range: 0.08–
0.21 d21). Because of ballasting of opal and calcite, sinking velocities were significantly higher for pellets
produced on T. weissflogii (322 6 169 m d21) and E. huxleyi (200 6 93 m d21) than on Rhodomonas sp. (35 6
29 m d21). 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.
AB - 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 ind21 h21 and 3.8 pellets
ind21 h21 and was significantly higher with T. weissflogii than with the other food sources. Average pellet size
varied between 2.2 3105 mm3 and 10.0 3105 mm3. 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 O2 mm23 d21,
2.86 fmol O2 mm23 d21, and 0.73 fmol O2 mm23 d21 in pellets produced on Rhodomonas sp., T. weissflogii, and E.
huxleyi, respectively. The average carbon-specific respiration rate was 0.15 d21 independent on diet (range: 0.08–
0.21 d21). Because of ballasting of opal and calcite, sinking velocities were significantly higher for pellets
produced on T. weissflogii (322 6 169 m d21) and E. huxleyi (200 6 93 m d21) than on Rhodomonas sp. (35 6
29 m d21). 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.
U2 - 10.4319/lo.2008.53.2.0469
DO - 10.4319/lo.2008.53.2.0469
M3 - Article
SN - 1939-5590
VL - 53
SP - 469
EP - 476
JO - Limnology and Oceanography
JF - Limnology and Oceanography
IS - 2
ER -