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An Alternative Framework to Assess Marine Ecosystem Functioning in Shelf Seas (AlterEco)

wave breaking

Completed project

Project start: May 2017  |  Project end: April 2020
Funder: NERC
Principal Investigator: Dr Tim Smyth
Other participants from PML: Andrea McEvoy, Dr Angus Atkinson

AlterEco aims to develop a new observational framework based upon the latest marine autonomous systems (MAS) to improve the spatio-temporal understanding of key shelf sea ecosystem drivers. This will be achieved through a sustained observational campaign in the North Sea, covering a 14 month period from winter-to-winter, providing repeat transects over a region sufficiently large to capture typical shelf sea mesoscale features and processes.

Continental shelf seas are typically less than 200m deep and can be described by the shallow ocean surrounding continental land masses. Due to their accessibility, shelf seas are commercially and economically important, and despite occupying only 7% of the surface ocean, shelf seas also play a major role in the global carbon cycle and marine ecosystem. Shelf seas are 3-4 times more productive than openocean, are estimated to support more than 40% of carbon sequestration and support 90% of global fish catches providing a critical food source for growing coastal populations. However, shelf seas are also exposed to climate driven and anthropogenic stress that could have a profound impact on their biological productivity, oxygen dynamics and ecosystem function.

AlterEco will address these issues by addressing four hypotheses:

  • Inter-annual variability in the seasonal cycle of shelf seas physical structure is predominantly driven by large scale boundary forcing.
  • Spatial gradients in the duration and intensity of stratification control the distribution of phytoplankton and zooplankton biomass and annually integrated productivity.
  • Spatial gradients in stratification, water depth and productivity control the development and intensity of oxygen deficiency in the North Sea.
  • Long-term variability of dominant physical and biogeochemical drivers means that static "baseline" conditions for shelf seas do not exist.


In the UK alone, marine data collection costs approximately £80 million per year, but there is increasing pressure across sectors to reduce these costs. Coupled with public demand for open access, verifiability and the need for sharing data across different stakeholders and users, has led to the creation of the UK Integrated Marine Observing Network (UKIMON). AlterEco will help achieve the aim of UK-IMON to provide the evidence base for future assessments of environmental status.