ECOSMO II(CHL): a marine biogeochemical model for the North Atlantic and the Arctic

Abstract

Abstract. ECOSMO II is a fully coupled bio-physical model of 3d-hydrodynamics with an intermediate complexity N(utrient) P(hytoplankton) Z(ooplankton) D(etritus) type biology including sediment-water column exchange processes originally formulated for the North Sea and Baltic Sea. Here we present an updated version of the model incorporating chlorophyll a as a prognostic state variable: ECOSMO II(CHL). The version presented here is online coupled to the HYCOM ocean model. The model is intended to be used for regional configurations for the North Atlantic and the Arctic incorporating coarse to high spatial resolutions for hind-casting and operational purposes. We provide the full descriptions of the changes in ECOSMO II(CHL) from ECOSMO II and provide the evaluation for the inorganic nutrients and chlorophyll variables, present the modeled biogeochemistry of the Nordic Seas and the Artic and experiments on various parameterization sets as use cases targeting chlorophyll a dynamics. The model evaluations demonstrated that the simulations are consistent with the large-scale climatological nutrient settings, and are capable of representing regional and seasonal changes. The Norwegian and Barents Seas primary production show distinct seasonal patterns with a pronounced spring bloom dominated by diatoms and low biomass during winter months. The Norwegian Sea annual primary production is around double that of the Barents Sea while also having an earlier spring bloom. The parameterization experiments showed that the representation of open ocean chlorophyll a benefits from using higher phytoplankton growth and zooplankton grazing rates with less photosynthesis efficiency compared to the original implementation of ECOSMO II, which was valid for the North Sea and the Baltic Sea representing coastal domains. Thus, for open ocean modeling studies, we suggest the use of the parameterization sets presented in this study.

Environmental Change at Deep-Sea Sponge Habitats Over the Last Half Century: A Model Hindcast Study for the Age of Anthropogenic Climate Change

“…The hybrid coordinates of the physical model, HYCOM (Bleck, 2002), allow for good vertical resolution in the upper layer for adequately representing the surface mixed layer as well as resolving the vertical structure of light-dependent biogeochemical processes in the photic zone, and densityfollowing coordinates provide good water mass conservation in the deep sea (Ross et al, 2016). The biogeochemical model, ECOSMO (Daewel and Schrum, 2013;Yumruktepe et al, 2021), includes the main phytoplankton functional types for the North Atlantic Ocean, nutrients, and a single layer of sediments with parameterizations for settling, resuspension and burial (when sediment can no longer be resuspended). The coupled model therefore lends itself to investigating interactions between physical and biogeochemical variables and to simulating the deep-sea environment, and it can be applied in studies of relevance to deep-sea organisms, including sponges (as in the present work).…”

“…ECOSMO, is a medium complexity biogeochemical model (Figure 1). The version used here, ECOSMO II(CHL) (Yumruktepe et al, 2021), resolves four nutrients (nitrate, phosphate, silicate and ammonium), two types of phytoplankton functional groups (diatoms and flagellates) as well as two classes of zooplankton functional groups (herbi-and omnivorous). In addition, state variables for both particulate and dissolved organic material, and oxygen are included.…”

“…The biogeochemical model has been described in detail in Daewel and Schrum (2013), hereafter referred to as DS2013. In the present study, the model is coupled to a different physical model and additional modification of the model configuration and parameterization are applied to make the model suitable for the area and the research question (Yumruktepe et al, 2021). The changes are further explained in the following.…”

An along-track biogeochemical Argo modelling framework, a case study of model improvements for the Nordic Seas

“…The input files that were used for the discussed experiment in the study are archived on Zenodo at Yumruktepe et al (2022a) 'experiments/example' folder. This folder includes the necessary files to reproduce the experiment.…”

“…This folder includes the necessary files to reproduce the experiment. The following web links are the sources of these input files and 'build_experiment.sh' included at Yumruktepe et al (2022a) is configured to connect to Author contributions. VÇY built the framework and together with EAM, JT and AS, they designed the experiments and VÇY carried them out.…”