Marine Research Findings of the VECTORS Project

This website provides access to the research results of the VECTORS project, which can be used to support marine management decisions, policies and governance as well as future research and investment. VECTORS was a large scale project that brought together more than 200 expert researchers from 16 different countries. It examined the significant changes taking place in European seas, their causes, and the impacts they will have on society.

Modelling future scenarios of the biogeochemistry of the three regional seas

The impact of climate change and river management on the three regional seas has been investigated using a coupled biogeochemical-hydrodynamic model under two contrasting climate change and mitigation policy scenarios. The model includes key ecosystem processes such as trophic energy flows and nutrient cycling and gives estimates of net primary production, chlorophyll concentration and other indicators. Simulations cover present-day conditions and two alternatives for the 2040s, representing high and low carbon emissions and river pollution. The same modelling framework was used for the three regional seas, enabling inter-comparison. The projections provide a sensitivity analysis of the susceptibility of the system to the pressures of change and mitigation strategies. They also provide inputs to higher trophic level and socio-economic models within VECTORS.


The models project increasing production in the Mediterranean under both scenarios, with a smaller increase under the lower emission global community scenario. The NW European Shelf shows decreasing production under both scenarios; Baltic production increases for higher emissions and reduces for lower emissions, in line with levels of riverine input.

The modelling system combines the hydrodynamic model POLCOMS1 with the lower trophic level model ERSEM2. It was run with the same model set-up and parameterisation for all three seas.

The model resolution is 0.1 degrees horizontally, with 40 vertical levels distributed according to depth. ERSEM traces the flow of nitrate, phosphate, silicate and carbon through the planktonic food-web and the related organic and inorganic matter. It includes four functional types of phytoplankton, three of zooplankton and one bacterial group. Future forcing data was applied using a ‘national responsibility’ scenario using SRES A2 and ‘global responsibility’ using SRES B1 climate model data345. River nitrate and phosphate for each scenario were based on results of the ELME project5. The national responsibility scenario represents higher carbon emissions and river pollution than global community.

The model results were used to map future primary and community production under the two scenarios, where community production is the difference between gross primary production and the total respiration of phytoplankton, zooplankton and bacteria. The same trend was found for both measures in all three seas.

In most areas of the western Mediterranean, differences between the two future scenarios are not significant. In the North Sea the difference is most significant in the north, with a greater decrease for the national responsibility scenario. In the Baltic the difference between scenarios was most significant for southern and coastal areas.


Mediterranean and Baltic nutrient levels are projected to change in line with riverine inputs, but the NW European Shelf is influenced by nutrient input from the Atlantic. High nutrient levels can be associated with eutrophication so these projections of where the greatest change in nutrient levels may occur are valuable.

Present day riverine inputs were set using data from the GlobalNEWS dataset ( Inputs in the future scenarios were set by modifying the present-day values using the predicted trends from the ELME dataset6. A strong or weak increase/decrease was translated to a 60% or 30% change respectively.

In the Mediterranean the difference between the two future scenarios was significant everywhere except in the far east of the basin and the Morocco coast. For surface nitrate the difference was significant in most areas of the north west shelf, but for phosphate it was only significant in the southern and western area. For the Baltic the difference between scenarios was significant everywhere.


Levels of dissolved inorganic carbon increase for all seas, implying rising acidity. For the Mediterranean and North Sea the increase is greater for the national responsibility scenario, but for the Baltic the increase is greater for the global community scenario because of the reduction in community production.

These changes are largely driven by the increase in atmospheric CO2 levels according to the IPCC scenarios A2 and B1, partly converted by the marine environment into biomass and potentially exported to the deep ocean and the sediments in relation to the levels of community production, which is the main indicator for the ecosystem’s capacity to absorb the atmospheric CO2 pressure. The atmospheric carbon concentration was taken to be 385 ppm for the present day, 505 ppm for the national responsibility scenario and 475 ppm for global responsibility.

The difference in DIC levels between the two scenarios was significant everywhere in the three regional seas, except for the southern Adriatic.

Relevance for Policy:
  • Common Fisheries Policy
  • Marine Strategy Framework Directive
  • Water Framework Directive
Data availability:

Availability:  Ecological Indicators derived from the product have been made available through the MEDINA project’s GEOSS portal

The data is published under the Creative Commons Attribute licence version 4.0, and is openly available. Due to the data volume data access is currently granted by contacting one of the authors ( or


Lead Author:

Momme Butenschön & Susan Kay
Plymouth Marine Laboratory (PML)
Date of research: January 2013

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This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 266445
© Vectors 2015. Coordinated by Plymouth Marine Laboratory.