Researchers from eight institutions and organisations have worked together to examine areas of sea or ocean located on the UK continental shelf to understand the sensitivity of these systems to human activities. The societal importance of these ecosystems extends beyond food production to include biodiversity, carbon cycling and storage, waste disposal, nutrient cycling, recreation, and renewable energy.
Martin Solan, lead principal investigator and professor in marine ecology at the University of Southampton, comments: “Our seafloors are teeming with life, from microscopic organisms to larger creatures such as fish and crabs. All interact as part of a complex system which plays a vital role in maintaining the health of the seabed and the rest of food web.
“Human intervention, such as fishing, pollution and activities causing climate change are all affecting these finely balanced ecosystems. Collectively, our research provides us with a new perspective on how the seafloor is being modified, for better or for worse—but more research is now needed to understand the longer-term consequences of such change for the wider environment and for society at large.”
The research team has analyzed the biodiversity, nutrient, metal, and carbon cycling in areas of the seafloor around the UK subject to different environmental conditions and human use. University of Southampton scientists focused on four main areas: the effects of climate change1, assessing the impact of bottom fishing2, understanding the importance of iron cycling across the seafloor4, and optimizing areas for study3. In relation to climate and fishing, the researchers conducted two experiments. One took sediment communities from different areas in the Irish Sea experiencing low, medium, and high levels of trawling activity and compared each sample. Another took different types of sediment (mud, sand, sandy mud, etc.) from the Celtic Sea and simulated, in a laboratory, how future climatic conditions will affect important seabed processes.
The researchers found that, in a variety of complex ways, communities adjusted to their new environments, with some species thriving and some taking up new roles. However, some species failed to adjust to the new conditions and could not survive. In particular, the scientists found that some species were able to withstand fishing pressure, but struggled with warmer climate conditions and raised CO2 levels.
Dr. Phil Williamson, from the University of East Anglia, who helped coordinate this research program, commented: “Much of what happens in the sea is out of sight and out of mind. This study has provided a wealth of insights into the natural recycling processes that are literally at the base of marine ecosystems, underpinning the many benefits that we obtain from the sea.”
The research is part of a special issue of the scientific journal Biogeochemistry and includes contributions from the University of Southampton, the Centre for Environment, Fisheries and Aquaculture Science (CEFAS), the National Oceanography Centre (NOC), University of Portsmouth, University of Oxford, Bangor University, Plymouth Marine Laboratory, and The Scottish Association for Marine Science (SAMS). The variety of projects which the Biogeochemistry special issue brings together, were conducted on three dedicated research cruises and other expeditions around the UK.
The research was part of the Shelf Sea Biogeochemistry program, investigating how natural and human processes interact in the seas around the UK.
Papers forming the Biochemistry Special Issue are:
1Vulnerability of macronutirents to the concurrent effects of enhanced temperature and atmospheric pCO2 in representative shelf sea sediment habitats
Lead author and institute: Jasmin Godbold, University of Southampton
2Mediation of macronutrients and carbon by post-disturbance shelf sea sediment communities
Lead author: Rachel Hale, University of Southampton
3An approach for the identification of exemplar sites for scaling up targeted field observations of benthic biogeochemistry in heterogeneous environments
Lead author and institute: Charlotte Thompson, University of Southampton
4Stability of dissolved and soluble Fe(II) in shelf sediment pore waters and release to an oxic water column
Lead author and institute: Jessica Klar, University of Southampton
5Community mediation on shelf-sea benthic nitrogen cycling following bottom trawling and organic enrichment
Lead author and institute: Marija Sciberras, Bangor University
6Benthic pH gradients across a range of shelf sea sediment types linked to sediment characteristics and seasonal variability
Lead author and institute: Briony Silburn, Centre for Environment, Fisheries and Aquaculture Science (CEFAS)
7Comparison of the ERSEM model with benthic biogeochemical measurements at two sites in the Celtic Sea and including a representation of advective pore water flow
Lead Author and institute: John Aldridge CEFAS
8Predicting the standing stock of organic carbon in surface sediments of the North-West European continental shelf
Lead author and institute: Markus Diesing, CEFAS
9Seasonal benthic nitrogen cycling in a temperate shelf sea; the Celtic Sea
Lead author and institution: Vas Kitidis, Plymouth Marine Laboratory (PML)
10Oxygen dynamics in shelf seas sediments incorporating seasonal variability
Lead author and institute: Natalie Hicks, Scottish Association for Marine Science (SAMS)