WP 3

Observation of inorganic carbon & nutrient dynamics

 

Work Package Leaders

 

Description

The research focus of WP3 is on investigating marine inorganic carbon and nutrient dynamics within individual oceanic eddies. These will be investigated by measuring  the distribution of different marine CO2 parameters, CO2 partial pressure (pCO2), dissolved inorganic carbon (DIC) and total alkalinity (TA) in the context of specific meso- and submesoscale feature and transport processes in and around eddies. Furthermore, the concentration of various nutrients (nitrate, phosphate, silicate) as well as the distribution of dissolved oxygen will be determined with high resolution within individual eddies.

An intensive sampling program during the planned field campaigns including underway pCO2 measurements including a wide range of autonomous high-tech devices equipped with biogeochemical sensors (see figure 1 A, B) will help to achieve the research objectives within work package 3. This high-resolution, multi-parameter study will gain new insight into the dynamics and functioning of the marine inorganic carbon and nutrient system within oceanic eddies and thus improve the qualitative and quantitative understanding of the role of eddies for the biological pump off West Africa.  

 

General Questions and Research topics

  • Investigate (sub-) mesoscale distributions of inorganic carbon parameters (e.g. DIC and TA) and nutrients within individual ocean eddies.
  • Determine the temporal and spatial variability of net carbon uptake (net community production, NCP) as well as oxygen consumption rates within and below the mixed layer inside ocean eddies.
  • Quantify air-sea gas exchange rates of CO2 and O2 and the relation with top layer dynamics and sub-mesoscale transport processes.
  • Estimate the carbon budget of different ocean eddy types and their regional importance (in cooperation with the other work packages).

The above mentioned objectives will be answered by means of an ambitious observation concept consisting of (i) regular biogeochemical time series observations (using the Cape Verde Ocean Observatory (CVOO), (ii) pre-cruise campaigns with a small Cape Verdean vessel (Islandia, see figure 2 A, B) and autonomous platform surveys as well as (iii) a comprehensive field studies with R/V Meteor in order to investigate and characterise the biogeochemical and sub-mesoscale transport processes within different ocean eddies.

 

Figure 1 A, B. A wave glider and B sail drone are autonomous operating plattforms equipped with different biogeochemical sensor measuring, depending on the platform, the following parameters: pCO2, O2, temperature, salinity, chl a, turbidity, gas tension (N2), meteorological dat as well as radiation during open ocean surveys. Picture credit: A saildrones.com, B  liquid-robotics.com  

 

 

 

Arne Körtzinger Björn Fiedler

 

Melf Paulsen

 

 

 

Figure 2 A. Research vessel Islandia off the coast of the island São Vicente (Cape Verde). Picture credit: GEOMAR

 

Figure 2 B. Seawater sampling with a CTD rosette on board of the research vessel Islandia. Picture credit: GEOMAR