The Marine Carbon Cycle from North to South along the Galathea route

Summary of the project

Aim

To collect a multidisciplinary dataset describing the upper ocean processes controlling ocean-atmosphere carbon exchange on a global scale.

Objectives
  • To quantify the marine carbon cycle in the upper ocean together with the airsea exchange of CO2, trace gasses and particle deposition from Greenland to Antarctica.
  • To compare the roles and contributions of different ocean regions in/to physical, chemical and biological processes in the global carbon and nutrient cycles.
  • To take advantage of new technology and remote sensing to quantify the role of ocean mesoscale activity – “ocean weather” – on the spatial variability of air-sea gas exchange of CO2 on the global scale.
Sampling strategy

Over the entire cruise track (see map below), continuous measurements of hydrographic, chemical (including pCO2) and biological (including chlorophyll a and fast repetition rate fluorescence (for determination of photosynthetic capacity)) will be carried out on surface water. In collaboration with another project, flow cytometric analysis of the composition of the microplankton community will be carried out. In addition, point measurements of nutrients, primary production and plankton composition will be made and analyzed in the laboratories. Samples for stable isotope (13C and 15N) distributions at various trophic levels of the food web will be periodically carried out. On deck, air- and optical measurements will be carried out. At selected intervals, CTD-casts with concurrent collection of water chemistry and plankton sampling will be taken. Those will provide information on the hydrographic conditions and the biological activity deeper in the water column. Net and pump collection of zooplankton as well as trawl fishing for after zooplanktivore fish will also be carried out at selected intervals. On some transects, an undulating platform carrying different instruments will be towed after the ship collecting measurements from 0-400 m. Each of the activities in the project involve the expertise from different research teams and the results from each of the activities are expected to provide new and important information related to processes influencing the cycling of carbon and the climate on Earth. However, the ambition of this project is to combine and coordinate all these activities from different scientific disciplines to develop a comprehensive description of the interaction between the processes involved in the carbon cycle.

Area of study

The cruise track is shown below: Sampling will be carried out over the entire route.