Iversen, MH; Poulsen, LK (2009): Fecal pellet ingestion rate and feeding behavior of Oithona similis, Calanus helgolandicus and Pseudocalanus elongatus from the North Sea. doi:10.1594/PANGAEA.730043, Supplement to:Iversen, Morten Hvitfeldt; Poulsen, Louise K (2007): Coprorhexy, coprophagy, and coprochaly in the copepods Calanus helgolandicus, Pseudocalanus elongatus, and Oithona similis. Marine Ecology Progress Series, 350, 79-89, doi:10.3354/meps07095
Studies of fecal pellet flux show that a large percentage of pellets produced in the upper ocean is degraded within the surface waters. It is therefore important to investigate these degradation mechanisms to understand the role of fecal pellets in the oceanic carbon cycle. Degradation of pellets is mainly thought to be caused by coprophagy (ingestion of fecal pellets) by copepods, and especially by the ubiquitous copepods Oithona spp. We examined fecal pellet ingestion rate and feeding behavior of O. similis and 2 other dominant copepod species from the North Sea (Calanus helgolandicus and Pseudocalanus elongatus). All investigations were done with fecal pellets as the sole food source and with fecal pellets offered together with an alternative suitable food source. The ingestion of fecal pellets by all 3 copepod species was highest when offered together with an alternative food source. No feeding behavior was determined for O. similis due to the lack of pellet capture in those experiments. Fecal pellets offered together with an alternative food source increased the filtration activity by C. helgolandicus and P. elongatus and thereby the number of pellets caught in their feeding current. However, most pellets were rejected immediately after capture and were often fragmented during rejection. Actual ingestion of captured pellets was rare (<37% for C. helgolandicus and <24% for P. elongatus), and only small pellet fragments were ingested unintentionally along with alternative food. We therefore suggest coprorhexy (fragmentation of pellets) to be the main effect of copepods on the vertical flux of fecal pellets. Coprorhexy turns the pellets into smaller, slower-sinking particles that can then be degraded by other organisms such as bacteria and protozooplankton.
Iversen, Morten Hvitfeldt (2009): Carbon turnover in sinking particles in the marine environment. PhD Thesis, Elektronische Dissertationen an der Staats- und Universitätsbibliothek Bremen, Germany, urn:nbn:de:gbv:46-diss000114915
NE_North_Sea_2004-2005 * Latitude: 54.815000 * Longitude: 3.321700 * Location: north-eastern North Sea * Device: Vertical plankton net (VPN) * Comment: Calanus helgolandicus females were collected in October 2004 and August 2005
North_Sea_2003 * Latitude: 54.815000 * Longitude: 3.321700 * Location: North Sea * Device: Vertical plankton net (VPN) * Comment: Pseudocalanus elongatus was collected in August 2003
Sound_2004 * Latitude: 56.024500 * Longitude: 12.641700 * Location: Strait of Øresund * Device: Vertical plankton net (VPN) * Comment: Oithona similis was collected in November 2004 in The Sound (Øresund, Denmark)