| back to students |
| First name: || Morten |
| Last name: || Iversen |
| Country: || Denmark |
|Carbon Turnover in Sinking Particles in the Marine Environment
|2000 – 2003
||Biology study, Roskilde University, DK
Bachelor in environmental biology:
|2003 – 2004
||Master in Biological Oceanography, Leibniz-Institut für Meereswissenschaften
Kiel (D) & Southern University of Denmark Odense (DK)
|2003 – 2004
||Performing experiments and writing a scientific paper: Drillet G, Iversen MH et
al. (2006)“Effect of cold storage upon eggs of the Calaniod copepod Acartia
tonsa (Dana) and their offspring” Aquaculture, Vol. 254, issues 1-4, p. 714-729
||Job description and location: Writing teaching material, Southern University of
Subjects; coral biology, ecosystems, temperate waters, tropical waters, marine
animal biology, ocean currents, and basic food webs.
|2004 – 2005
||Master thesis on degradation processes of fecal pellets, Danish Institute for
Fisheries Research Charlottenlund (DK) & Southern University of Denmark Odense
|2006 – 2009
||Ph.D. thesis at Max Planck Institute in Bremen, Alfred-Wegener-Institut für
Polar- und Meeresforschung in Bremerhaven and at MARUM - RCOM (Research Center
Working title: Carbon turnover in sinking particle in the marine environment.
|Scientific Interests and Goals:
|The main objective of this study is to investigate the carbon turnover in
sinking particles in the epi- and mesopelagic zones of the oceans, i.e. down to
a depth of 1000 meter. Not only organic carbon (POC) is important in this
perspective, but also inorganic carbon (PIC) since high CaCO3 production
potentially lead to large net burial of carbon. Therefore accurate measurements
of POC and PIC fluxes are needed to address the remineralization pathways of
marine particles. 90% of the vertical export from the epipelagic zone is
remineralized in the mesopelagic, still the remineralization mechanisms are
partly a mystery. The purpose of this study is to investigate the importance of
fluxes from the particles in the carbon cycle. These investigations will both be
performed in laboratory to understand the general governing mechanisms and in
situ (in the upwelling zone vest of Cape Blanc, Africa) to obtain actual natural
estimates of remineralization prosesses. The investigations consist of:
Experimental investigations of fecal pellet:
1. Measurements of carbon remineralization in copepod fecal pellets
2. Sinking rates of fecal pellets; comparing of measurements versus
estimations via model calculations.
3. Measurements of carbonate dissolution in copepod fecal pellets
4. The role of zooplankters in particle remineralization. (e.g.
fragmentation (coprorhexy) or ingestion (coprophagy) of particles).
Experimental investigations of marine snow aggregates:
5. Organic carbon degradation in marine snow aggregates (using microsensors
and Winkler titration).
6. The importance of scavenging of ballast material for sinking velocities.
7. Carbonate dissolution in marine snow aggregates (using microsensors).
8. Observations of coccolithophore aggregation to estimate the importance
of formations of micro environments in marine snow (potentially leading
to carbonate dissolution).
9. Estimates of field abundance, content, and activity of marine snow
|Iversen MH, Poulsen LK (2007) "Fecal pellet grazing behaviour of three species
of copepods: Calanus helgolandicus, Pseudocalanus elongatus, and Oithona
similis" MEPS 350: 79-89
Ploug H, Iversen MH, Koski M, Buitenhuis ET (2008) "Production, oxygen
respiration rates, and sinking velocity of copepod fecal pellets" Limnol.
Oceanogr. 53(2): 469-476
Poulsen LK, Iversen MH (2008) "Degradation of copepod fecal pellets by the
plankton community of Øresund (Denmark) during a year´s succession" MEPS 367:
Ploug H, Iversen MH, Fischer G (2008) "Ballast, sinking velocity, and apparent
diffusivity within marine snow and zooplankton fecal pellets: Implications for
substrate turnover by attached bacteria" Limnol. Oceanogr. 53(5): 1878-1886