WP 5 leader: Anja Engel   anja.engel (at) awi.de   (AWI)

Objectives:

• Quantify effects of ocean acidification on photosynthetic carbon metabolism & nitrogen fixation
• Assess the consequences for elemental stoichiometry, partitioning of organic matter into dissolved and particulate phases, and vertical transport
• Search for changes in gene expression for selected genes relevant for nutrients and carbon metabolism
• Determine effects on the production of climate relevant biogases
• Assess effects on the speciation and bioavailability of major and trace nutrients (Fe, Zn)

Description of work and role of participants:

T5.1: Determine community level responses to ocean acidification of photosynthetic carbon and nitrogen fixation, exudation, partitioning into dissolved and particulate organic matter, stoichiometry, and production of climate relevant biogases in off-shore mesocosm CO2 perturbation experiments (IFM-GEOMAR, UiB, UCAM, AWI, PML, NIOZ, NOC)

T5.2: Assess combined effects of acidification and changes in temperature, light, and nutrients on carbon and energy fluxes in key phytoplankton taxa (AWI, IFM-GEOMAR, PML, NIOZ)

T5.3: Determine expression of selected genes for nutrients and carbon uptake, exudation, and carbonic anhydrase and the influence on gene diversity in (meta)genomic databases in laboratory and mesocosm experiments (IFM-GEOMAR, NIOZ)

T5.4: Model carbon fluxes and energy allocation at the cellular level based on results obtained in T5.3 (AWI)

T5.5: Determine changes in the speciation and bioavailability of major and trace nutrients (Fe, Zn) and related effects on photosynthesis and carbon metabolism (NIOZ, NOC)