Scientists call for more research on how human activities affect the seabed

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 teaming 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 analysed 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 optimising 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 programme, 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.