Biogeochemistry, macronutrient and carbon cycling in the benthic layer

Lead Research Organisation: Bangor University
Department Name: Sch of Ocean Sciences

Abstract

The coasts and shelf seas that surround us have been the focal point of human prosperity and well-being throughout our history and, consequently, have had a disproportionate effect on our culture. The societal importance of the shelf seas extends beyond food production to include biodiversity, carbon cycling and storage, waste disposal, nutrient cycling, recreation and renewable energy. Yet, as increasing proportions of the global population move closer to the coast, our seas have become progressively eroded by human activities, including overfishing, pollution, habitat disturbance and climate change. This is worrying because the condition of the seabed, biodiversity and human society are inextricably linked. Hence, there is an urgent need to understand the relative sensitivities of a range of shelf habitats so that human pressures can be managed more effectively to ensure the long-term sustainability of our seas and provision of societal benefits. Achieving these aims is not straightforward, as the capacity of the seabed to provide the goods and services we rely upon depends on the type of substrate (rock, gravel, sand, mud) and local conditions; some habitats are naturally dynamic and relatively insensitive to disturbance, while others are comparatively stable and vulnerable to change. This makes it very difficult to assess habitat sensitivities or make general statements about what benefits we can expect from our seas in the future.

Recently, NERC and DEFRA have initiated a major new research programme on Shelf Sea Biogeochemistry that will improve knowledge about these issues. In response to this call, we have assembled a consortium of leading scientists that includes microbiologists, ecologists, physical oceanographers, biogeochemists, mathematical modellers and policy advisors. With assistance from organisations like CEFAS, Marine Scotland and AFBI, they will carry out a series of research cruises around the UK that will map the sensitivity and status of seabed habitats based on their physical condition, the microbial and faunal communities that inhabit them, and the size and dynamics of the nitrogen and carbon pools found there. The latest marine technologies will measure the amount of mixing and flow rates just above the seabed, as well as detailed seabed topography. These measurements will allow better understanding of the physical processes responsible for movement and mixing of sediment, nutrient, and carbon. At the same time, cores will be retrieved containing the microbial and faunal communities and their activity and behaviour will be linked to specific biogeochemical responses. Highly specialised autonomous vehicles, called landers, will also measure nutrient concentrations and fluxes at the seabed. Components of the system can then be experimentally manipulated to mimic scenarios of change, such as changing hydrodynamics, disturbance or components of climate change. This will be achieved in the field by generating different flow regimes using a submerged flume or, in the laboratory, using intact sediment communities exposed to different levels of CO2, temperature and oxygen. By measuring the biogeochemical response and behaviour of the microbial and faunal communities to these changes, we will generate an understanding of what may happen if such changes did occur across our shelf seas.

We will use all of this information to 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 will 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

Planned Impact

Commercial private sector and the knowledge economy: new and innovative methodologies, equipment and techniques, and combined state-of-the-art technologies (>£2.3 million in-kind, see JeS) will assess what the primary physical and biogeochemical controls of shelf productivity are up to shelf sea scales. Since many interests rely on the marine environment, beneficiaries will be varied. By sharing expertise and knowledge, a world-leading manufacturer of microsensors and microscale instrumentation and an internationally recognized marine environmental data acquisition company will benefit from exploitable opportunities, e.g. new visualisation tools that enable holistic understanding of large-scale ecosystem processes.

Policy professionals, governmental and devolved governmental organisations: The importance of shelf seas to society extends beyond fisheries to wider issues, such as biodiversity, carbon cycling and storage, waste disposal, nutrient cycling, and renewable energy resources. Consortium expertise will contribute to these UK priority challenges. The UK Marine & Coastal Access Act (MCAA), UK Climate Change Act, EU Habitats Directive and EU Marine Strategy Framework Directive (MSFD) support sustainable use of the marine environment. They also support the UK vision for achieving 'clean, healthy, safe productive and biologically diverse ocean and seas' (UK Marine Science Strategy). We will provide a coherent framework for sound evidence based-science in support of these policy instruments and statutory requirements. For example, the MSFD aims to achieve Good Environmental Status in EU marine waters by 2020, but we lack understanding of the magnitude and synchronicity of change in SSEs. Our research will directly inform Descriptor 1 (biological diversity) and 6 (seabed integrity) for a wide range of sediment habitats over time, which is important because the determination of good environmental status may have to be adapted over time (addressed in Task 2) "in view of the dynamic nature of marine ecosystems and their natural variability, and given that the pressures and impacts on them may vary with the evolvement of different patterns of human activity and the impact of climate change" (MSFD). Our work will also inform environmental monitoring programmes: OSPARs Joint Assessment and Monitoring programme, the Eutrophication Monitoring Programme and The Clean Seas Environment Monitoring Programme (CSEMP, led by consortium member CEFAS). Task 1-3 complement the outcomes of CESEMP and provide scientific evidence to OSPAR. Similarly, experimental scenarios and modelling approaches will provide needed information for (i) the EU Water Framework Directive (the requirement for 'good chemical and ecological status' by 2015 does not account for climate change) and, (ii) the UK White Paper for MCAA (it is unclear how commitments to "look ahead at the predicted impacts of climate change on the marine environment, how marine activities will contribute towards it, and how they are affected by it" will be achieved). Finally, other EU instruments, such as the Habitats Directive (introduced in 1992), the EU Common Fisheries Policy (revised in 2002) and national legislation such as the UK MCAA and Scottish Marine Act, assume that removal (or control) of direct pressures will result in ecosystem recovery and/or species persistence. Our programme includes experimental scenarios and modelling approaches to provide further information on the vulnerability of SSEs in environmental futures under multiple pressures (Task 3). Our outputs will also help NERC meet its science theme challenges.

Public, wider community: active engagement with a variety of organisations is detailed in Pathways to Impact (PtI).

Skills & training: In addition to academic progression, early career researchers will gain experience and receive mentoring in running a large interdisciplinary programme, as well as training in communication skills and scientific methodology
 
Description In the presence of physical disturbance, irrespective of sediment type, the mediation of macronutrient and carbon cycling increasingly reflects the decoupling of organism-sediment relations. Indeed, it is the traits of the benthic species that reside at the sediment-water interface, or that occupy deeper parts of the sediment profile, that are disproportionately expressed post-disturbance, that are most important for sustaining biogeochemical functioning.

Nitrogen transformation in shelf sandy sediments is dependent on the stimulation of specific nitrogen cycling pathways that are associated with differences in the composition and context-dependent expression of the functional traits that belong to the resident bioturbating macrofauna community.

Otter trawling may be affecting organic-matter remineralization and nutrient cycling through sediment resuspension and burial of organic matter to depth rather than through the loss of bioturbation potential of the benthic community. The effects of fauna and bioturbation potential on biogeochemistry were very limited in both mud and sand habitats.

In conclusion, our hypothesis that the effects of trawling on biogeochemistry are larger in mud is supported, but the hypothesis that these effects are mediated by changes in the infauna is not supported.
Exploitation Route The management of trawling impacts when assessing the integrity needs to understand how trawling disturbance affects biogeochemistry. These results imply that management of trawling on muddy sediments should have higher priority.
Sectors Agriculture

Food and Drink

Environment

 
Description They have being used to prepare a summary document for policy makers. https://www.uk-ssb.org/shelf_seas_report.html
First Year Of Impact 2018
Sector Agriculture, Food and Drink,Environment,Government, Democracy and Justice
Impact Types Policy & public services

 
Description Seafish
Amount £69,569 (GBP)
Organisation Seafish 
Sector Public
Country United Kingdom
Start 11/2016 
End 11/2017
 
Title Submission to BODC 
Description Our datasets from the cruise were submitted to BODC, https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/46ecc183-c08d-2211-e053-6c86abc0d02c/ 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact Fully documents and makes available data as required by NERC 
URL https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/46ecc183-c08d-2211-e053-6c86abc...
 
Description BENTHIS 
Organisation European Commission
Department Seventh Framework Programme (FP7)
Country European Union (EU) 
Sector Public 
PI Contribution This project runs in parallel and has similar aims. Pooling resources has meant we can achieve more. The EU grant that we hold is worth Euro 230k
Collaborator Contribution This project runs in parallel and has similar aims. Pooling resources has meant we can achieve more.
Impact Ongoing
Start Year 2012
 
Description BENTHIS Final symposium 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Jan Geert Hiddink, Rijnsdorp, Jennings, Kaiser, Hilborn, Bolam, Van Denderen, Ivanovic, O'Neill et al. How does trawling affect benthic ecosystems? BENTHIS Final Symposium: Benthic Ecosystem Fisheries Impact Studies. 14 June 2017, Brussels.
Year(s) Of Engagement Activity 2017
 
Description SHELF SEAS THE ENGINE OF PRODUCTIVITY UNDERPINNING SCIENCE FOR POLICY AND MANAGEMENT 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact A report was produced for policymakers and managers to communicate the programme outcomes.
Year(s) Of Engagement Activity 2018
URL https://www.uk-ssb.org/shelf_seas_report.pdf