Workshops

Clisap B3 and adjoined scientists meet on a regularly basis. Aim of the meetings is to discuss the results achieved and focus on the common tasks in the next years.

On October 28, 2016 the B3 group and adjoined scientists had a meeting with a talk given by Kay Emeis and a talk by Johannes Pätsch.

Kay Emeis presented in his talk the status of the Habitat Atlas of the North Sea (http://www.noah-project.de). One key point of this Atlas is to demonstrate the impact of global climate change and direct anthropogenic disturbances on German coastal habitats.

Johannes Pätsch showed in his presentation results of the early diagenesis model for the shelf sea system implemented into ECOHAM. The original sediment model for the global ocean developed at the MPI-Hamburg has been adapted to shelf sea dynamics which act rather on the annual-  than on century scale.

On May 24, 2016 the B3 group and adjoined scientists had a follow-up meeting with three talks, two concerning upwelling and one from the IHF – group about zooplankton and other activities.


Katharina Six provided an overview of the modelling activities at the MPI - Hamburg concerning upwelling. She introduced the new BUS (Benguela Upwelling System) which is able to reproduce observed features using advanced nitrogen cycling processes and a mesh refinement around  Benguela upwelling.


Edurado Zorita showed an overview of upwelling dynamics at the Eastern Boundary Upwelling (EBU) – systems and the Arabian Sea. He discussed whether or not the Bakun – hypothesis could be confirmed. Bakun hypothesized that the global upwelling will be intensified with global warming.

Tim Dudeck focused in his talk on zooplankton size spectra and diversity, which can be used to identify biodiversity. Additionally, he gave an overview of other activities at the IHF: A zooplankton - herring larvae dataset and trophic interaction analysis in the English Channel (Tim Dudeck), a North Sea transect and LOPC zooplankton identification (Marc Hufnagl), offshore windfarm research on zooplankton distribution (Dominik Auch, Tim Dudeck, Jens Floeter, et al.), herring survival and climate response in the Baltic Sea (Björn Illing), and the new CERES project (Myron Peck). Due to unpublished data his talk is available by request.

On February 5, 2016 the B3 group and adjoined scientists had meeting with a talk given by Iris Hinrichs.

Iris Hinrichs presented in her talk the status of the biogeochemical North Sea Climatology. She showed data products of nitrate, phosphate and silicate. Next steps will be to integrate  also ammonium, oxygen and chlorophyll.

On June 1, 2015 the B3 group and adjoined scientists had a follow-up meeting with three talks given by Inga Hense’s group.

Inga Hense provided an overview of ACCOEM (Advancement of Coupled Climate Ocean Ecosystem Models) activities. She highlighted the biological-physical feedback mechanisms in the upper ocean and suggested to consider this bidirectional coupling in future climate projection runs.

Richard Hofmeister introduced the modeling tool “Framework of Aquatic Biogeochemical Models” (FABM) that allows a flexible combination of biogeochemical and hydrodynamical models. As an example, he had shown projection scenarios highlighting the effect of ocean acidification on cyanobacteria bloom formation and nitrogen fixation.

Jana Hinners’ talk on consequences of alterable phytoplankton traits for ecosystem dynamics in a changing environment was about her PhD-project in which she aims to combine experimental and modeling work on evolutionary adaptation of dinoflagellates.

On February 18 the B3 group and adjoined scientists continued the discussion from December 2014 and had two talks which were given by members of the IHF, Tim Dudeck and Marc Hufnagl.

Tim’s talk contained two parts: The first one was on long-term (1987-2013) dynamics in winter zooplankton size distribution, abundance and species composition from the southern North Sea (English Channel). Strong interannual variations and additionally a decrease in mean size with time was shown. Further analysis concerning the reasons are in progress.  The potential implications for higher trophic level species, in particular prey availability for herring larvae, were also presented and discussed. The second presentation was on results from the North Sea Triaxus Transect in summer 2014. Highly resolved data on Temperature, Salinity (CTD), Chlorophyll, Oxygen (sensors), Zooplankton size (LOPC), Fish distribution (hydroaccoustics) and currents (ADCP) are available and soon ready for comparison with model runs. Marc and Tim highlighted the opportunity for collaboration and data sharing on this extensive new ecosystem dataset.

Tim also reported on coupling the ecosystem model ECOHAM (Pätsch & Kühn, 2008) with the normalized size-spectrum model by Zhou et al. (2010) based on his analysed datasets. This idea was intensively discussed by the group and further strategies to get feedback from the size-spectrum model into the ecosystem model were developed.

Marc’s talk on the North Sea application of the end-to-end model Atlantis showed first results of inter annual variability of top predators, upper trophics and intermediate levels. The model is based on hydrodynamic simulations by HAMSOM (Pohlmann, 1996), initial conditions for the year 1991 were among others obtained from ecosystem model ECOHAM (Lorkowski et al., 2012) as well as North Sea fish and Benthos surveys (IBTS).  A large number of parameter adaptions was required to represent the North Sea system which is now in a state to be used for analyzing different large scale scenarios. One tested  scenario was based on large closures of fishing areas due to the installation of marine protected areas and wind parks. The results showed an increase of cod standing stock mainly due to an increased population density as a result of decreased fishing pressure which outweighed the decrease in available fishing grounds.

References

  • Lorkowski, I. Pätsch, J., Moll, A. and Kühn, W., 2012. Interannual variability of carbon fluxes in the North Sea from 1970 to 2006 – Competing effects of abiotic and biotic drivers on the gas exchange of CO2 . Estuarine, Coastal and Shelf Science, 100, 38-57, doi: 10.1016/j.ecss.2011.11.037.
  • Pohlmann, T., 1996. Predicting the thermocline in a circulation model of the North Sea .1.Model description, calibration and verification. Cont. Shelf Res. 16(2): 131-146.
  • Pätsch, J. and Kühn, W., 2008. Nitrogen and carbon cycling in the North Sea and exchange with the North Atlantic - a model study, Part I. Nitrogen budget and fluxes. Continental Shelf Research,  28: 767-787.
  • Zhou M., Carlotti F., Zhi Y., 2010 A size-spectrum zooplankton closure model for ecosystem modelling. Journal of Plankton Research 32 (8) 1147-1165

Clisap B3 and adjoined scientists met on 9 December 2014. Aim of the meeting was to discuss the results achieved and focus on the common tasks in the next years. We had four short talks which were discussed intensively.

The first talk was given by Iris Hinrichs who is the leading person to build the biogeochemical climatology for the Greater North Sea. The following discussion was pertained to the expected high variability and sparsity of the data. We confirmed Iris’ suggestion to treat in this first step only data from 1960 on.

The second talk was held by Johannes Pätsch. He is the first author of the manuscript “Are global models able to simulate regional shelf dynamics? A comparison of a global model with regional models and observations for the North Sea region” which has been developed by different scientists of German partner institutes and colleagues who built the Hydrographic climatology ICDC for the North Sea. Johannes reported on the different hydrodynamic features which are important also for ecosystem modeling.

Thomas Pohlmann gave the next lecture on hindcasts and projections. One of the findings was that in the future winter temperatures are increasing stronger than summer temperatures with the consequence of an ongoing destabilization of the water column. In the following discussion it was emphasized to coordinate the different model applications and runs within the different institutes. In this way ensemble runs for climate scenarios could serve for common publications.

The fourth lecture was given by Katharina Six. She demonstrated the MPI model application for the upwelling region off the Namibia coast. A comparison of observations and model results showed that the horizontal resolution of the meteorological forcing was crucial for the improvement of the model outcome. It was suggested to compare or use also REMO runs for this region.

Eduardo Zorita was the last speaker of the day. He presented the hypothesis of a future intensification of global upwelling due to stronger heating of land than of sea. This hypothesis could not be stated for the upwelling regions he investigated. In the Arabian Sea even a decrease could be seen.

We decided to have a next meeting in February. Then we can hear about activities of the colleagues at the IHF.