Posted on July 26, 2017

Man-made structures in the North Sea - Do they matter?

The question founding the INSITE Joint Industry Program is whether the myriad of fixed man-made structures (MMS) placed in the North Sea (NS) over the past 50 years have any impact on the marine ecosystem.

When looking at maps showing the 1,300 offshore petroleum installations, 1,800 turbines at wind farms and not least the 25,000 ship wrecks one gets the impression that the originally soft bottom of the NS is littered with artificial hard bottom substrates, some of which extend from the bottom to the sea surface. Yet when flying across the NS the visible ones seem only like pinpricks in a vast ocean.

So do they matter? Have the physical presence of the MMS or the specialised ecological communities that they support, had a detectable impact on the overall ecosystem structure and function in the NS? What is the nature of this effect? Could it be that a change in the distribution and behaviour of top predators have a cascading effect down the food web? Could it be that the introduction of eggs and larvae of new hard bottom species have changed the plankton community? Do hard bottom species use the MMS as stepping stones for migration and recruitment to new areas? These and similar questions form the basis for INSITE, the overall aim of which is “to provide stakeholders with the independent scientific evidence-base needed to better understand the influence of man-made structures on the ecosystem of the North Sea”.

INSITE Phase 1, the Foundation Phase, started in 2014 and terminates at the end of 2017. It supports eight international research projects that aim to provide ecological data and research tools for further studies on the impact of MMS:

Development, implementation and testing of numerical models to study the ecosystem structure in space and time.

Generate an inventory of available data on the NS ecosystem and facilitate their use in INSITE.

Development of means to assess ecological connectivity of MMS and means to track dispersion and migration patterns of selected species.

Mapping the hard bottom community structure on selected MMS in various regions of the NS. 

Measuring ecological properties around MMS in shallow and deep water.

The projects have come a long way to fulfil their objectives, but have also revealed challenges. There is e.g. limited data available to allow validation of the developed models and test their sensitivity, especially for the Central and Northern NS. And there is a serious lack of data on the biology of keystone hard bottom species used as model organisms in dispersal studies. These and other issues such as how to monitor the possible effects of MMS cost-effectively, and how will such effects impact MMS management will be dealt with in INSITE Phase 2, the Data Acquisition and Enhancement Phase, starting in 2018.

Associate Professor Torgeir Bakke is Chairman of the INSITE Independent Scientific Advisory Board