Phytoplankton Ecosystem; Southern Ocean Biogeochemical Gate; Coccolithophores; Ocean Stratification; Diatoms; Southern Ocean; Climate Change; Ocean Biogeochemistry; Ocean Acidification; CO2
Bracher Astrid, Bouman Heather A., Brewin Robert J. W., Bricaud Annick, Brotas Vanda, Ciotti Aurea M., Clementson Lesley, Devred Emmanuel, Di Cicco Annalisa, Dutkiewicz Stephanie, Hardman-Mountford Nick J., Hickman Anna E., Hieronymi Martin, Hirata Takafumi, Losa Svetlana N., Mouw Colleen B., Organelli Emanuele, Raitsos Dionysios E., Uitz Julia, Vogt Meike, Wolanin Aleksandra (2017), Obtaining Phytoplankton Diversity from Ocean Color: A Scientific Roadmap for Future Development, in Frontiers in Marine Science
, 4, 1-15.
Vichi Marcello, Sathyendranath Shubha, Vogt Meike, et al. (2017), Colour and Light in the Ocean (CLEO) 2016: A Scientific Roadmap from the CLEO Workshop Organised by ESA and PML
Ferrari Gianna (2017), Phaeocystis in the Southern Ocean
Swan Chantal M., Vogt Meike, Gruber Nicolas, Laufkoetter Charlotte (2016), A global seasonal surface ocean climatology of phytoplankton types based on CHEMTAX analysis of HPLC pigments, in Deep Sea Research Part I: Oceanographic Research Papers
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Brandenberg Julia (2015), Statistical Analysis of Global Phytoplankton Biogeography in Mechanistic Models and Observations
, Master Thesis, D-USYS, ETH Zürich, Zürich.
Swan C. Vogt M. Gruber N. Laufkoetter C. (2015), Supplement to: 'A global seasonal surface ocean climatology of phytoplankton types based on CHEMTAX analysis of HPLC pigments', Dataset #855412
Aschwanden Mathias (2015), Variability in the elemental stoichiometry of marine phytoplankton in relation to community structure
The Southern Ocean acts as a biogeochemical gatekeeper that governs the exchange of carbon and other biogeochemically important elements such as nitrogen and silicon between the “cold” (mostly deep) and the “warm” (mostly upper) parts of the ocean. It thereby controls not only the large-scale oceanic distribution of these elements and hence ocean productivity, but also the ocean-atmosphere partition of CO2 and hence climate. The phytoplankton community in this nexus is key in determining the operation of this biogeochemical gate. Of particular relevance is the diatom dominated belt of biogenic silica (opal) production in the Subantarctic to Antarctic zone, where iron limited growth leads to a rapid exhaustion of silicic acid, causing this nutrient to be “trapped” in the cold ocean. This is not the case for nitrate, which leaks out into the warm ocean to fuel primary production at low latitudes. North of this silica belt, a large pan-Southern Ocean belt of calcite production is presumed to exist, likely dominated by coccolithophores. It is neither well known nor understood what controls these belts and their distinct phytoplankton ecosystems, and what the biogeochemical consequences are in terms of export of carbon and ballasting materials (opal and calcite). Furthermore, current global coupled physical-ecological models fail to represent these distinct zonal differences in ecosystem structure. This poses a particularly severe shortcoming when considering that these phytoplankton groups are susceptible to future global change (warming, changing circulation, ocean acidification). This strongly limits our ability to predict how the Southern Ocean biogeochemical gate will operate in the future, with important repercussions on global biogeochemical cycles and climate. Herein, we propose to investigate the structure and activity of the marine phytoplankton ecosystem in the Southern Ocean with a particular emphasis on developing a quantitative understanding of its role in controlling the Southern Ocean biogeochemical gate at present and in the future. To this end, we combine empirical analyses of existing phytoplankton community observations based on direct enumeration, pigment analyses, and biogeochemical properties with simulation results from an eddy-resolving regional coupled ocean physical, biogeochemical, ecological model for the Southern Ocean. More specifically, we plan to use the recently completed MAREDAT data compilation together with other data to establish a robust observationally based synthesis of the phytoplankton ecosystem structure in the Southern Ocean. We will further exploit a large suite of ancillary and co-located data to uncover the relationships between nutrient supply, phytoplankton community composition, and export. We will subsequently explore the potential mechanistic drivers of the discovered linkages using a newly developed Southern Ocean setup of the Regional Oceanic Modeling system (ROMS) to which we have coupled the Biogeochemical Elemental Cycling Model (BEC) and which we will extend by including an explicit representation of coccolithophores.The use of a regional model permits us to employ a higher resolution compared to a global model, which is needed in order to fully resolve the mesoscale eddies that are so critical in this region. Through a series of perturbation simulations for the present-day, as well as time-window simulations for the future under a high CO2 scenario, we will explore the sensitivity of the plankton ecosystems to these perturbations, testing our hypothesis of strong floral shifts.