The ocean stores huge amounts of carbon dioxide (CO2) that would otherwise be in the atmosphere.
Marine organisms play a critical role in this process, but emerging evidence indicates that climate models are not fully accounting for their impact.
This undermines carbon policies, such as national net zero targets.
This biological influence on future ocean storage of carbon (BIO-Carbon) research programme is carefully designed to produce new understanding of biological processes. It will provide robust predictions of future ocean carbon storage in a changing climate.
The World Climate Research Programme (WCRP), which coordinates climate research internationally and is sponsored by UN organisations, has expressed its greatest priorities as three questions.
This programme will address two of those questions:
- what biological and abiological processes drive and control ocean carbon storage?
- can and will climate-carbon feedbacks amplify climate changes over the 21st century?
There are three interlinked programme challenges, which will address three aspects of biological influence:
Challenge one: how does marine life affect the potential for seawater to absorb CO2, and how will this change?
The ability of the ocean to absorb CO2 is influenced by its alkalinity. Reducing alkalinity pushes more of the dissolved carbon in seawater into the form of CO2.
This reduces the capacity of the ocean to take up further CO2 from the atmosphere.
Seawater alkalinity is influenced by a range of natural processes. The most important of these is the biological production of calcium carbonate (for example, by molluscs and fish), which removes alkalinity from seawater.
As the calcium carbonate sinks, it dissolves and the alkalinity is returned to the seawater.
Maintaining the vertical distribution of alkalinity fundamentally sets the capacity of our oceans to take up CO2. However, estimates of global ocean calcium carbonate production, vertical transport and dissolution vary by up to a factor of five.
This uncertainty is important because failure to reproduce alkalinity accurately in a climate model significantly impacts future projections of ocean CO2 uptake and storage.
Examples of significant knowledge gaps relating to key processes include:
- what organisms are producing highly soluble carbonates in the surface ocean, and where?
- which forms of calcium carbonate are dissolving where in the ocean?
- what are the factors involved in the dissolution of different forms of carbonate, and what is their sensitivity to the anticipated impacts of climate change?
Challenge two: how will the rate at which marine life converts dissolved CO2 into organic carbon change?
Primary production by marine phytoplankton converts a similar amount of CO2 into organic material each year as do all land plants combined.
Climate models cannot constrain this crucial global flux to within a factor of three for the contemporary climate, which points to major gaps in understanding.
Furthermore, uncertainty about our estimates for how oceanic primary production will change under climate warming has increased, rather than lessened, this decade. Whether global primary production will increase or decrease is unknown.
Primary production is strongly influenced by ocean warming and the availability of light and nutrients. However, the contributions of changes in these drivers to trends across climate models are poorly constrained.
The importance of organism interactions and metabolism, and their associated demands for carbon and other resources, is neglected by climate models. This is despite emerging observational indications of their significance.
Examples of knowledge gaps relating to key processes, operating across different scales, include:
- what controls the efficiency of primary production?
- what are the contributions of nutrient recycling and the consumption of phytoplankton by zooplankton to this efficiency?
- how do these processes vary across different ocean environments, and how might future change, such as warming and acidification, affect them?
Challenge three: how will climate change-induced shifts in respiration by the marine ecosystem affect the future ocean storage of carbon?
Organic carbon produced in the upper ocean cannot be returned to the atmosphere until it is converted back into CO2 by the respiration of marine organisms.
Deeper ocean respiration supports longer carbon storage as it takes longer to return to the ocean surface and make contact with the atmosphere.
We still have poor understanding of how respiration varies with depth, location or season.
We know it reflects the diversity of the organisms, from bacteria attached to sinking dead material to fish migrating daily between the surface and the ocean interior.
We also know that these organisms are responding to anthropogenic changes, such as changes in temperature that affect the metabolism of organisms.
In addition, existing models only reproduce a limited selection of relevant processes, with no consistency in that selection across models.
Examples of significant knowledge gaps relating to key processes include:
- what is the relative influence of size, shape and composition of non-living organic material in determining the rate at which it is converted back to CO2?
- what are the relative magnitudes of the CO2 generated by bacterial degradation of non-living organic matter and that respired directly by other organisms?
- how might ongoing changes in the environment (for example, to oxygen or temperature) affect respiration?
In addressing challenges one, two and three, research will provide a fundamental understanding of key biological processes that are globally relevant.
By encapsulating this new knowledge in a robust modelling framework, it will examine the resulting feedback on future predictions for how global ocean carbon storage may change.
Additionally, it will provide new parameterisations of key processes for inclusion in the next generation of climate models, and ‘emergent constraints’ to identify clearly erroneous forecasts.
The use of emergent constraints has been successfully applied to other areas of climate science, such as a constraint on climate sensitivity provided by air temperature variability or cloud feedbacks. However, it is yet to be adopted widely in marine science.
The BIO-Carbon programme aims to highlight the importance of international waters to discussions on carbon policy.
All BIO-Carbon projects are therefore required to focus research on processes that are globally relevant, in waters:
- within the open ocean water column that regulates carbon storage
- beyond the continental shelf break
- where the seafloor is typically at a depth greater than 1,000m.
BIO-Carbon fieldwork projects, which will be funded through a future opportunity, will be focused in the North Atlantic.
This is where the programme’s resources can be most effectively mobilised, and is a region where the relevant processes can be studied.
The outcomes of this research programme will:
- enhance our understanding of key biological processes that affect how carbon storage by the global ocean will change in the future
- significantly improve global ocean carbon budget projections, to better inform policy development and decision making in support of net zero ambitions
- provide new parameterisations of key processes and emergent constraints on global model behaviour for use in simulations feeding into the Intergovernmental Panel on Climate Change’s (IPCC) seventh assessment report
- implement new parameterisations and constraints in a suite of global models in order to provide a robust assessment to 2100 of the biologically associated changes in global ocean carbon storage, and their sensitivity to key processes identified by this programme. This assessment should be suitable for inclusion in IPCC’s seventh assessment report
- provide a significant UK contribution to the UN Ocean Decade outcome for ‘a predicted ocean’ by improving our ability to model oceanic responses under anthropogenic influence
- address two priorities of the WCRP’s grand challenge on carbon feedbacks in the climate system.
Apply for funding to analyse existing global models and observations, potentially informed by laboratory data. Identify major knowledge gaps and rank them by their impact on carbon storage.
Your research outputs are expected to inform the development of future fieldwork and modelling proposals, as part of further BIO-Carbon programme funding opportunities (see the ‘additional information’ section).
For example, you should identify significant knowledge gaps likely to be tractable by the fieldwork programme, and fundamental limitations in how current models represent the carbon system.
The outputs from your project must reflect a broad perspective. For example, you might take into account the range of model outputs from the Coupled Model Intercomparison Projects 6 (CMIP6) initiative.
You must include a statement about how your proposal will contribute towards the wider aims of the programme.
You should also have a strategy to gather input from a wide range of experts. You must provide a clear plan for how you will engage with the national and international community to achieve this.
No fieldwork or associated studentships will be funded.
A community workshop will be held as a hybrid event in early March 2023. You must provide evidence at this workshop to inform the geographic and seasonal focus of the programme’s North Atlantic cruise plan.
The workshop will be part of a cruise plan development process overseen by the programme champion.
This process will inform the BIO-Carbon Programme Advisory Group’s (PAG) recommendation to NERC on the cruise plan, which is part of a future fieldwork funding opportunity.
See the ‘delivery and coordination’ section for more information about the PAG.
Following the workshop, you should engage with applicants to help them develop their proposals for the fieldwork funding opportunity.
Please include funding in your budget to travel to the workshop. However, where possible you should hold project meetings virtually as a more sustainable and cost-efficient alternative to in-person meetings.
You will be required to submit a mid-term report to the PAG in January 2023.
You can request funding for up to 12 months. Your project must start no later than 3 July 2022.
The full economic cost of your project can be up to £250,000. NERC will fund 80% of the full economic cost.
We will fund one project.
For NERC-relevant data, you must adhere to the NERC data policy. You should produce an outline data management plan as part of your proposal.
NERC will pay the data centre directly on behalf of your programme for archival and curation services. However, you should ensure that you request sufficient resources to cover preparation of data for archiving by the research team.
Read the NERC data policy.