Logo Universitat Bremen
Page path:

Research goals

The main objective of SeaPump is to quantify the processes (biological, chemical, and physical) shaping the vertical flux of organic carbon at the base of the euphotic zone, in the twilight zone (100 to 1000 m), and in the deep ocean. This will be done by detailed investigations of the turnover of sinking marine particles within distinct depth-layers though the water column; with emphasis on the importance of microbial degradation, zooplankton flux feeding, and ballasting effects on the vertical export.
To accomplish the overall research goal of SeaPump, three intertwined research hypotheses are planned:
  • Hypothesis 1 (H1): Changes in food web structure and function determine the particle flux and flux attenuation.
  • Hypothesis 2 (H2): Delivery of organic matter to the deep ocean and sea floor occur as pulse fluxes.
  • Hypothesis 3 (H3): Definition of distinct water depth layers according to degradation rates and sinking velocities of particles will improve predictions of particulate organic matter export.
Hypothesis 1 investigates the processes controlling export flux and attenuation at different depths in the three research areas seasonally (see Research areas). This work will be a combination of in situ observations during ship cruises and laboratory work.
Hypothesis 2 investigates long-term changes in export flux to identify the triggering mechanisms for pulse fluxes. This work will involve collection of data using newly developed ship board measurements as well as data analysis from combinations of long-term moorings, satellite observations, and already existing data sets from the three research regions and other studies.
The combination of Hypothesis 1 and Hypothesis 2 will illuminate the controlling factors on the biological pump (organic carbon pump).
Hypothesis 3 combines the results from Hypothesis 1 and Hypothesis 2 into a model to identify the most important parameters for export flux and attenuation. Hypothesis 1 will provide information on food web interactions and Hypothesis 2 information on temporal and spatial changes in the efficiency of the organic carbon pump. The goal of the modelling is to identify the controlling parameters from the food web structure and composition on export fluxes to construct a forward model which can forecast the Seasonal and regional food web interactions with the biological pump (see figure above).