Ph.D. project by Louise Kjeldgaard Poulsen (DIFRES)
Supervisors: Thomas Kjørboe (DIFRES) and Benni Winding Hansen (Roskilde University)
The vertical flux of material in the oceans has important implications: It influences the global climate by removing CO2 from the atmosphere and it impacts pelagic food web structure and biomass, including the biomass of fish stocks. A mechanistic and detailed understanding of vertical flux processes is needed to understand and model these fundamental functions.
Marine snow aggregates and copepod fecal pellets are believed to be the main sources of vertical flux in the ocean. Copepods are important because they occur ubiquitously and are present year-round in the oceans. They therefore have the potential to contribute substantially to the total production of sinking vehicles and hence to the downward flux of organic matter.
The overall aim of this project is to examine the role of copepods in regulating vertical material flux in the ocean by both producing and degrading fecal pellets.
The vertical flux of copepod fecal pellets is governed by 3 component processes: (i) the rate at which fecal pellets are produced; (ii) the rate at which they sink; and (iii) the rate at which they are being degraded. Each of these individual processes will be studied in laboratory and field experiments at the level of the individual copepod. Further more the integrated result of the component processes by will be examined by quantifying bulk fecal pellet fluxes in the sea.
