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Shelf Seas Biogeochemistry research programme: biogeochemistry, macronutrient and carbon cycling in the benthic layer

Chlorophyl, May 2014. Courtesy of PML remote sensing group

Completed project

Project start: September 2013  |  Project end: April 2018
Funder: Natural Environment Research Council (NERC)
Principal Investigator: Professor Steve Widdicombe
Other participants from PML: Amanda Beesley, Louise McNeill, Carolyn Harris, Dr Helen Findlay, Dr Karen Tait, E. Malcolm S. Woodward, Joana Nunes

The shelf seas are of major importance to society, providing a diverse range of goods, such as fisheries, renewable energy, transport and services like carbon and nutrient cycling. This project aimed to provide a better understanding of the functioning of the shelf seas and how they respond to global change and human pressures.

The shelf seas are hugely valuable to life on Earth, but they are under considerable stress as a result of overfishing, habitat disturbance, climate change and other impacts. However, even within the relatively well-studied European shelf seas, fundamental biogeochemical processes are poorly understood.

Three dedicated research cruises and multiple supplemental research cruises in the Celtic, Irish and North seas, directly quantified the pools and exchanges of macronutrients and carbon across a range of sediment habitats using an extensive range of physical, biological, chemical, acoustic and optical techniques in order to generate a holistic understanding of the biogeochemistry of shelf sea systems.

Combining these observations with laboratory and field experiments the specific aims of the project were to:

  • quantify the short term stocks and flows of N, P, Si and C in both cohesive and non-cohesive sediments,
  • assess the potential role of shelf sea sediments in long term carbon storage,
  • evaluate the role of macrofaunal invertebrates in mediating sediment biogeochemistry,
  • determine the influence of natural & anthropogenic sediment disturbance on process rates, including the role of diffusive and pumped sediment water exchange and resuspension.



All of this information to was then used assess the relative vulnerability of areas of the UK seabed by overlaying the observation and experimental results over maps of various human pressures, which will be of value to planners and policymakers. Mathematical models were used to test future scenarios of change, such as opening or closing vulnerable areas to fishing or anticipated changes in the factors that control nutrient and carbon stocks. This will be valuable in exploring different responses to external pressures and for deciding which management measures should be put in place to preserve our shelf seas for future generations.