TY - JOUR
T1 - Copepod guts as biogeochemical hotspots in the sea
T2 - Evidence from microelectrode profiling of Calanus spp
AU - Tang, Kam W.
AU - Glud, Ronnie N.
AU - Glud, Anni
AU - Rysgaard, Søren
AU - Nielsen, Torkel Gissel
PY - 2011/3
Y1 - 2011/3
N2 - The environmental conditions inside the gut of Calanus hyperboreus and C. glacialis were measured with microelectrodes. An acidic potential hydrogen (pH) gradient was present in the gut of C. hyperboreus, and the lowest pH recorded was 5.40. The gut pH of a starved copepod decreased by 0.53 after the copepod resumed feeding for a few hours, indicating the secretion of acidic digestive fluid. A copepod feeding on Thalassiosira weissflogii (diatom) had slightly lower pH than that feeding on Rhodomonas salina (cryptophyte). Oxygen was undersaturated in the gut of both C. hyperboreus and C. glacialis, with a steep gradient from the anal opening to the metasome region. The central metasome region was completely anoxic. Food remains in the gut led to a lower oxygen level, and a diatom diet induced a stronger oxygen gradient than a cryptophyte diet. The acidic and suboxic–anoxic environments of the copepod gut may support iron dissolution and anaerobic microbial activities that otherwise are not favored in the well-buffered and oxygenated ambient ocean.
AB - The environmental conditions inside the gut of Calanus hyperboreus and C. glacialis were measured with microelectrodes. An acidic potential hydrogen (pH) gradient was present in the gut of C. hyperboreus, and the lowest pH recorded was 5.40. The gut pH of a starved copepod decreased by 0.53 after the copepod resumed feeding for a few hours, indicating the secretion of acidic digestive fluid. A copepod feeding on Thalassiosira weissflogii (diatom) had slightly lower pH than that feeding on Rhodomonas salina (cryptophyte). Oxygen was undersaturated in the gut of both C. hyperboreus and C. glacialis, with a steep gradient from the anal opening to the metasome region. The central metasome region was completely anoxic. Food remains in the gut led to a lower oxygen level, and a diatom diet induced a stronger oxygen gradient than a cryptophyte diet. The acidic and suboxic–anoxic environments of the copepod gut may support iron dissolution and anaerobic microbial activities that otherwise are not favored in the well-buffered and oxygenated ambient ocean.
U2 - 10.4319/lo.2011.56.2.0666
DO - 10.4319/lo.2011.56.2.0666
M3 - Journal article
SN - 0024-3590
VL - 56
SP - 666
EP - 672
JO - Limnology and Oceanography
JF - Limnology and Oceanography
IS - 2
ER -