Implementation of Antarctic Krill into the Ocean-Ecosystem Model FESOM-REcoM-2 and its Effects on Southern Ocean Biogeochemistry.

Karakus, Onur
Hauck, Judith
Völker, Christoph
Fach Salihoğlu, Bettina Andrea
Hagen, Wilhelm
In this study, a three-dimensional, coupled ocean ecosystem model (FESOM- REcoM2) is used to investigate the effect of krill on the biogeochemistry of the Southern Ocean. The implementation of Antarctic krill in the model was done in three steps. 1) A second zooplankton group was implemented, which grazes on diatoms, mesozooplankton and nanophytoplankton (in order of descending preference). 2) A new detritus group was added to the model, which represents faster-sinking krill faecal pellets. 3) The grazing impact of both zooplankton groups on detritus was described. Afterwards, four different simulations (control and three krill simulations for previously described steps) were conducted to evaluate, how the implementation of the new zooplankton group and additional features affected biogeochemical processes in the Southern Ocean. In our krill simulation, the spatial distribution of krill biomass in the Southern Ocean was reasonably reproduced. Preliminary results showed that the proportion of living compartments (phytoplankton and zooplankton groups) in the model changed, which led to different POC (particulate organic carbon) flux pathways to the deep ocean. Zooplankton biomass contribution to total carbon biomass increased from 2.4% to 10% in our model in Southern Ocean. The contribution of zooplankton to POC production doubled. The implementation of krill in the ecosystem model enhanced nutrient recycling in the upper ocean layer. Therefore, our novel krill implementation improved the bias between model and observations in surface spatial distributions of the macronutrients silicic acid and nitrate.
Ocean Sciences Meeting 2020, (16 - 21 February 2020)


Simulation of annual plankton productivity cycle in the Black Sea by a one-dimensional physical-biological model
Oğuz, Temel; Ducklow, H; MalanotteRizzoli, P; Tuğrul, Süleyman; Nezlin, NP; Ünlüata, Ü (American Geophysical Union (AGU), 1996-07-15)
The annual cycle of the plankton dynamics in the central Black Sea is studied by a one-dimensional vertically resolved physical-biological upper ocean model, coupled with the Mellor-Yamada level 2.5 turbulence closure scheme. The biological model involves interactions between the inorganic nitrogen (nitrate, ammonium), phytoplankton and herbivorous zooplankton biomasses, and detritus. Given a knowledge of physical forcing, the model simulates main observed seasonal and vertical characteristic features, in p...
Transport of Antarctic krill (Euphausia superba) across the Scotia Sea. Part II. Krill growth and survival
Fach Salihoğlu, Bettina Andrea; Murphy, Eugene J. (2006-06-01)
A time-dependent, size-structured, physiologically based krill growth model was used in conjunction with a circulation model to test the hypothesis that Antarctic krill (Euphausia superba) populations at South Georgia are sustained by import of individuals from upstream regions. Surface phytoplankton concentrations along the simulated drifter trajectories were extracted from historical Coastal Zone Color Scanner (CZCS) measurements and sea ice biota concentrations were calculated from sea ice concentration ...
Modeling the impact of tidal flows on the biological productivity of the Alboran Sea
Sanchez-Garrido, Jose C.; Naranjo, C.; Macias, D.; Garcia-Lafuente, J.; Oguz, T. (2015-11-01)
The control of phytoplankton production by tidal forcing in the Alboran Sea is investigated with a high-resolution ocean circulation model coupled to an ecosystem model. The aim of the modeling efforts was to elucidate the role of tides in sustaining the high biological productivity of the Alboran Sea, as compared with the rest of the Mediterranean subbasins. It is shown that tidal forcing accounts for an increase of phytoplankton biomass and primary productivity in the basin of about 40% with respect to a ...
Modeling the Impact of Macrozooplankton on Carbon Export Production in the Southern Ocean
Karakus, Onur; Voelker, Christoph; Iversen, Morten; Hagen, Wilhelm; Wolf-Gladrow, Dieter; Fach Salihoğlu, Bettina Andrea; Hauck, Judith (2021-12-01)
Macrozooplankton and its grazing pressure shape ecosystem structures and carbon pathways in the Southern Ocean. Here, we present the implementation of "polar macrozooplankton" as a plankton functional type and a related fast-sinking detritus class (fecal pellets) into the biogeochemical model REcoM-2. We use the model to assess major carbon pathways and ecosystem structure in the Southern Ocean south of 50 degrees S. The model represents zooplankton biomass and its spatial distribution in the Southern Ocean...
Comparative analyses and modelling for regional ecosystems of the Black Sea
Cokacar, T; Ozsoy, E (1997-06-19)
A zero dimensional ecosystem model is applied to the Black Sea to simulate the behaviour of its regional ecosystems. The modelling is guided by the analyses of the seasonal changes of mixed layer depth, nutrients and chlorophyll-a in the model regions, based on the available data in these areas of the Black Sea. Nutrients are continuously supplied to the adjacent coastal area by rivers, and in the other regions, mixed layer nutrient concentrations generally increase by mixing in winter. Despite the scarcity...
Citation Formats
O. Karakus, J. Hauck, C. Völker, B. A. Fach Salihoğlu, and W. Hagen, “Implementation of Antarctic Krill into the Ocean-Ecosystem Model FESOM-REcoM-2 and its Effects on Southern Ocean Biogeochemistry.,” presented at the Ocean Sciences Meeting 2020, (16 - 21 February 2020), San Diego, United States Of America, 2020, Accessed: 00, 2021. [Online]. Available: