Microbial dynamics at the air-sea interface and their impact on cycling of climate-active gases
Results from the METEOR cruise (M91) to the upwelling region off Peru showed that SML formation, composition and stability are related to biological productivity (Engel and Galgani 2016). Increasing wind speed disrupts the SML biofilm as indicated by lower accumulation of gel particles such as transparent exopolymer particles (TEP). At high wind speed a depletion of TEP in the SML was often observed, indicating TEP export from the SML, either by sea spray or by aggregation with sinking particles.
- The surface ocean under high CO2 conditions
The results of a large-scale mesocosm study indicate that ocean acidification can affect the abundance and activity of microorganisms during phytoplankton blooms, resulting in changes in the composition and dynamics of organic matter in the SML (Galgani et al. 2014). Phytoneuston and bacterial abundances in the SML were positively affected by CO2. Proteinaceous gels in the SML seemed to respond differently to acidification compared to polysaccharidic gels.
- Bacterial cycling of climate-active trace gases
Oceanic bromocarbons are highly reactive volatile organic compounds and may contribute up to 40% of stratospheric ozone depletion in mid latitudes. High sea-air fluxes of bromocarbons in the tropical ocean have been related to microbial cycling in the surface ocean, mainly due to phytoplankton and bacteria, but the underlying processes and magnitude of the biogenic sources in the diverse marine environments are poorly known.
Besides that, it is also unclear how environmental parameters such as light, temperature and pH may influence bromocarbon cycling rates in the ocean. In order to understand seasonal and spatial fluctuations of oceanic bromocarbon emissions and to project their future development, we study microbial production and removal processes in the surface ocean during cruises to low and high latitudes and combines them with observational data of bromocarbon and organic matter concentrations in the water and atmosphere.
See also Halocarbon-Group (http://www.geomar.de/en/research/fb2/fb2-ch/workgroups/team-halocarbon/#c25614)
- Biological Impact of Ocean Acidification (BIOACID II), PI: Prof. Anja Engel, PhD candidate Birthe Zäncker
- Surface Ocean Processes in the Anthropocene (SOPRAN II + III), PI: Prof. Anja Engel, Dr. Luisa Galgani
- Biological cycling of climate-active trace gases in the surface ocean (Kiel Excellence Cluster “The Future Ocean”; CP1405), PI: Dr. Sonja Endres
- The sea surface microlayer (Kiel Excellence Cluster “The Future Ocean”; CP1146); PhD candidate Alexander Dreshchinskii, PI: Prof. Anja Engel
- Surface Ocean Lower Atmosphere Study (SOLAS)
- SCOR Sea Surface Microlayer Working Group (WG141)