On 7 April 2010 R/V Polarstern will depart form Punta Arenas for its Atlantic transfer to Bremerhaven. The cruise will be utilized for continuous investigations of atmospheric and marine properties as well as for energy and material fluxes between ocean and atmosphere. The following projects will be carried out:

Autonomous measurement platforms for energy and material exchange between ocean and atmosphere (OCEANET - Atmosphere & Ocean)

In order to provide a solid basis for the observational monitoring of energy and material exchange between ocean and atmosphere it is planned to develop an autonomous observation system for operational use onboard available cargo- and research vessels. The project is based on a network of expertise from IFM-GEOMAR, Kiel (CO₂-/O₂-fluxes, photosynthetic status, energy budget, remote sensing), Leibniz Institute for Tropospheric Research, Leipzig (active remote sensing), GKSS Institute for Coastal Research, Geesthacht (ferry box, remote sensing of marine biology with ENVISAT/MERIS) and AWI Bremerhaven (CO₂-system, marine infrastructure of Polarstern).

Chemical measurements: Operation of autonomous systems as well as new instruments for measurement of parameters of the marine CO₂ system (pCO₂, pH, δ¹³C-DIC) as well as of ancillary parameters.

Biological measurements: Phylogenetic diversity and metabolic activity of nitrogen-fixing microorganisms will be determined along the meridional transects by molecular biological methods as well as with on board microcosm experiments.

Atmospheric measurements: The scientific focus of atmospheric measurements to be carried out during this cruise will be placed on radiation & microwave remote sensing (multi-channel microwave radiometer), air-sea interaction and fluxes (turbulent fluxes of momentum, sensible heat, latent heat, and CO₂ by the inertial dissipation method), and Lidar observations (multi-channel Raman-Lidar Polly for aerosols).

Bio-optical measurements for satellite ground truthing and ocean optical modelling

Use of remote sensing data in combination with in-situ measurements of ocean optics, phytoplankton productivity and composition of particulate organic carbon with the aim to improve estimates of global marine primary production and the distribution of major phytoplankton functional groups.

Atmospheric Dust and Irradiation effects on Ocean surface processes – Biogeochemistry in the Atlantic Ocean (ADIOS-BAO)

The aim of the project is to produce comprehensive data on crustally derived trace metals (Al, Fe and Ti) and phosphate in the surface ocean over contrasting regions of the Atlantic Ocean. In addition simultaneous measurements of photochemical influenced parameters (hydrogen peroxide, nitrite and CDOM) will allow the examination the influence of irradiation on dust dissolution via redox processes.

Analysis of the chemical composition of marine organic aerosol along a meridional transect of the Atlantic Ocean

Innovative methods for aerosol analysis employing high-mass resolution proton-transfer-reaction mass-spectrometer (hi-res-PTR-MS) and stable isotope ratio mass spectrometry (IRMS) will allow characterizing the chemical composition of organic aerosols over different regions of the Atlantic Ocean.

Measurement of concentration and isotopic signature of hydrogen in surface ocean and atmosphere

This project aims to measure the concentration and isotopic signature of hydrogen in the atmosphere and surface ocean. The ultimate goal is to quantify oceanic hydrogen emissions and their role in the global atmospheric hydrogen cycle. The latitudinal distribution of atmospheric hydrogen will be used to improve atmospheric models.

Abyssal temperature fluctuations in the Vema Channel

Revisit to the Vema Sill and Extension sites for continuation of a time series of high precision CTD observations of the coldest AABW in the Vema channel.

Cruise ANT XXVI/4 will be based primarily on continuous measurements in surface ocean and atmosphere. In addition a daily hydrographic station including CTD-rosette sampling and radiation measurements will be performed.

Polarstern will arrive in Bremerhaven on May 17, 2010.