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.

Food web (delta-13C, delta-15N) along the European Atlantic coast: is there a geographic/latitudinal gradient?

The European coast is extensive and therefore contains many different ecosystems from the Baltic to the Mediterranean Sea, with different weather and current patterns, different water temperatures and salinities and different organisms, different anthropogenic impacts, and different topographies. The number of marine species known in this part of the Atlantic Ocean is ca. 30,0001. Although the species richness of coastal ecosystems of the Baltic Sea (ca. 75 plant and animal species), the North Sea (more than 1,500 species), and the Mediterranean (more than 17,000 species) is different, trophic relationships in all these systems are assumed to be similar. However, little attention has been paid in Europe to understand whether variations in the composition of OM pools and consumers exist at large spatial scales across and among different geographic regions.


No major geographic/latitudinal differences between three European main regions, the Baltic Sea, the North Sea and English Channel, and the Bay of Biscay, were found in the delta-13C and delta-15N values of organic matter pools and two dominant bivalves, Mytilus spp. and Macoma balthica.

Samples were collected at 18 sampling stations along the European continental coast, including estuarine and coastal ecosystems from the Baltic Sea (northern Sweden) to the southern coast of the Bay of Biscay, in spring and autumn 2004. Stations were grouped into three main geographic regions corresponding to latitudinal/longitudinal gradients in terms of main environmental factors, such as water salinity and temperature. Stations 1–6 were located in the BS (Baltic Sea), stations 7–12 in the NS (North Sea and English Channel), and stations 13–18 along the Bay of Biscay (BB) (Fig. 1).

The lack of geographic/latitudinal trends found in this study for Mytilus spp. and M. balthica (Fig. 2), has implications for food web studies along the Atlantic coast because most of the values are consistent over a large area and show no significant differences. Therefore, the present study can be used for the determination of trophic baselines along the European Atlantic coast.

Besides this, Mytilus spp. was more 13C-depleted than M. balthica (Fig. 3), suggesting the two bivalve species had different diets. This is consistent with differences in feeding behaviour of Mytilus spp. and M. balthica, known as obligatory suspension and facultative-deposit feeders, respectively23.


At some stations, irrespective of geographic location, both bivalves showed delta-15N values up to 18–20%, indicating local and/or episodic eutrophic conditions, probably due to waste water discharge.

High delta-15N values were found at individual stations including Lomma (Baltic Sea), Wilhelmshaven, Grevelingen and Westerschelde (North Sea), and Loire and Arcachon (Biscay Bay). The delta-15N values of bivalves at those stations were similar, indicating the same trophic level of the two bivalves within a food web. Thus, it is suggested that pathways of energy flow from OM pools to dominant bivalves is more related to local environmental conditions than to geographic regions across the European coastline. The latter results also indicate that both Mytilus spp. and M. balthica can be used as bio-indicators of anthropogenic eutrophication, as found for other bivalve species45.

Relevance for Policy:
  • Common Fisheries Policy
  • Convention on Biological Diversity
  • Directive on Maritime Spatial Planning and Integrated Coastal Management (forthcoming)
  • Environmental Impact Assessment Directive
  • EU Biodiversity Strategy
  • Integrated European Maritime Policy (IMP)
  • International Convention for the Control and Management of Ship's Ballast Water and Sediments
  • Marine Strategy Framework Directive
  • Strategic Environmental Assessment Directive
  • Water Framework Directive


Lead Author:

Paolo Magni
Institute for Coastal Marine Environment of the National Research Council (IAMC-CNR)
Date of research: December 2012

Related articles:

Food web change along a nearshore-offshore gradient

Modelling future scenarios of biogeochemistry 

Social economic impact assessment for the future 

The link between tourism and ecosystems 

Changes in the upper trophic level: impact on fish

Connectivity: plaice spawning and nursery areas 

|< <  1 2 3 4 5 6 7 8 9 10 ...  > >|

Print this page

The content of this website may be subject to copyright, if you wish to use any of the information or figures please contact the attributed author(s).
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.