Controls over Ocean Mesopelagic Interior Carbon Storage (COMICS)

Lead Research Organisation: University of Southampton
Department Name: Sch of Ocean and Earth Science

Abstract

The surface ocean is home to billions of microscopic plants called phytoplankton which produce organic matter in the surface ocean using sunlight and carbon dioxide. When they die they sink, taking this carbon into the deep ocean, where it is stored on timescales of hundreds to thousands of years, which helps keep our climate the way it is today. The size of the effect they have on our climate is linked to how deep they sink before they dissolve - the deeper they sink, the more carbon is stored. This sinking carbon also provides food to the animals living in the ocean's deep, dark 'twilight zone'. Computer models can help us predict how future changes in greenhouse gas emissions might change this ocean carbon store. Current models however struggle with making these predictions. This is partly because until recently we haven't even been
able to answer the basic question 'Is there enough food for all the animals living in the twilight zone?'. But in a breakthrough this year we used new technology and new theory to show that there is indeed enough food. So now we can move on to asking what controls how deep the carbon sinks. There are lots of factors which might affect how deep the material sinks but at the moment we can't be sure which ones are important. In this project we will make oceanographic expeditions to two different places to test how these different factors affect carbon storage in the deep ocean. We will measure the carbon sinking into the twilight zone and the biological processes going on within it. Then we will determine if the systems are balanced - in other words, what goes in, should come out again. We will then write equations linking all the parts of the system together and analyse them to make them more simple. At the same time we will test whether the simple equations are still useful by seeing if they produce good global maps of ocean properties for which we have lots of data. Finally, when we are happy that our new equations are doing a good job we will use them in a computer model to predict the future store of carbon in the ocean.

Planned Impact

COMICS will ultimately result in improved predictions of future ocean carbon storage, hence contributing essential knowledge for evidence based policy-making. This project has been designed to provide an immediate and direct benefit to the ongoing development of the NERC-Met Office UK Earth System Model (ESM) which is the UK's platform for future IPCC assessments. COMICS will establish a pipeline for new insights from our in situ work to be translated through into recommendations for novel model parameterisations for a key component of the global carbon cycle, which will then be incorporated in the UK-ESM. This will build on work currently funded under the NERC Process Based Model Evaluation programme, which is part of the UKESM development strategy. To ensure that the results from our observational programme are translated into practical parameterisations for climate models, Prof Colin Jones (Head of the UKESM project) will sit on our project advisory board.

In addition to the Met Office, we have engaged stakeholders in Cefas (an executive Defra agency) which is responsible for delivering evidence-based advice on marine management issues. Our proposed work on marine environment modelling and predicting the marine impacts of climate change are directly relevant to Cefas. COMICS will ensure a direct link to Cefas/Defra through the inclusion on our programme advisory board of Dr Robert Thorpe (Fisheries Scientist) who will also provide a route to policy makers via the Marine Climate Change Centre.

COMICS will contribute to the UK's international standing, and capacity building in developing nations. One output of this project will be computationally efficient new parameterisations for carbon remineralisation which can be incorporated into any suitable global biogeochemical climate model. COMICS thus has the potential to influence future climate models at the international level. We will also contribute to capacity building in developing nations by proposing researcher exchange programmes and mentoring development of early career researchers.

COMICS also includes a programme of public engagement activities, targeting both the general public and the next generation of marine scientists. These activities aim to increase awareness of the importance of ocean carbon uptake for regulating Earth's climate in an era of increasing greenhouse gas emissions.

These goals will be achieved through a dedicated impact effort, through dedicated staff time from NOC's communications office and the COMICS programme manager, with input from all members of the COMICS team.

Our impact programme includes funds for: a targeted stakeholder event that will be held at the end of year 3 in London to present our results from the specific standpoint of policy makers; design and distribution of glossy literature aimed at stakeholders and the general public; development of a programme website including professional graphic design; development of display materials for public events, such as science fairs.

Proposed additional impact activities for which we do not request NERC funds include: a Royal Society scientific programme meeting to which both stakeholders and the broader academic community will be invited (to take place in year 4); a collaborative researcher exchange programme with South African colleagues via the Newton Fund; supporting development of early career researchers from developing countries through the POGO fellowship scheme; daily cruise blog from on board the ship; Twitter feed (#comicscarbon), including two live Twitter Q&A events during the cruises; articles aimed at the interested public in Planet Earth; editorial feature in a popular science magazine; regular media
releases associated with cruises, journal articles, events etc.

Publications

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Ainsworth J (2023) Iron cycling during the decline of a South Georgia diatom bloom in Deep Sea Research Part II: Topical Studies in Oceanography

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Duret MT (2019) Prokaryotic niche partitioning between suspended and sinking marine particles. in Environmental microbiology reports

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Hemsley V (2023) Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone in Deep Sea Research Part II: Topical Studies in Oceanography

Studentship Projects

Project Reference Relationship Related To Start End Student Name
NE/M02072X/1 02/04/2017 30/03/2023
2383361 Studentship NE/M02072X/1 27/09/2017 29/09/2021 Joanna Ainsworth
 
Description In the classic paradigm of marine nitrogen cycling, particulate organic matter sinks out of the sunlit surface ocean, then the organically bound nitrogen is remineralised and released as ammonium - ammonification - to fuel nitrification in the twilight to dark ocean, and replenish the immense deep-sea nitrate reservoir. In other words, sinking particles are considered as the major input of nitrogen into the deep ocean, and ammonification rates should follow the same exponenential decay trend as particle fluxes; while nitrification rates should be enhanced in sinking particles, especially in the upper twilight ocean. However, few attempts have been made to actually measure these processes. Missing also in these considerations are the non-sinking suspended particles. Recent work has revealed distinct microbial communities residing in suspended and sinking particles, thus suggesting different biogeochemical functions they confer[1]. Using marine snow catchers to distinguish particle phases into fast-, slow- and non- sinking, we measured ammonification and nitrification rates at mesopelagic depths in the Southern Ocean and the Benguela Upwelling system. We found that non-sinking fractions often gave comparable to even greater ammonification rates than sinking particles, and ammonification rate decay into the mesopelagic is far slower than expected from the classic Martin curve. This is further supported by parallel microrespiration rate measurements. Meanwhile, nitrification enhancment in sinking particles was generally insignificant. Parallel metatranscriptomic analyses further reveal stronger ammonium uptakes and assimilation, as well as protein degradation activities particularly in the suspended rather than sinking fractions. These results together indicate a much more important role in both carbon and nitrogen cycling played by suspended particles than previously recognised.
Exploitation Route The relationships between carbon and nitrogen cycling assocated with sinking and suspended particles can be used to inform and to some extent help parameterise more realistic biogeochemical models that evaluate the efficiency of the ocean's biological carbon pump, and hence the ability to sequester atmospheric CO2 into the deep ocean. Molecular biology data generated further support observations on the activity distribution of these microbial processes and metabolic pathways, and potentials to yield novel bioproducts. Manuscripts synthesising these findings are under preparation.
Sectors Environment

Pharmaceuticals and Medical Biotechnology

 
Description BSc thesis research
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
Impact Trainings include the use of stable isotopic analyses and integration with other biogeochemical data for microbial and biogeochemical rate measurements. Skills acquired include gas chromatography and mass spectrometry, and other chemical analytical techniques.
 
Description Development of course materials for undergraduate and postgraduate courses - Oceanic biological carbon pump and particle fluxes in the oceans
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
 
Description Integrated Masters (MSci) and BSc Research Training
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Influenced training of practitioners or researchers
Impact First-class MSci and upper second class BSc theses.
 
Description Integrated Masters Research (MSci) Training
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
Impact Research trainings in molecular biology, especially metatranscriptomics, involving both wet laboratory practical work and subsequent bioinformatic analyses of large datasets - the latter also provide valuable transferrable skills in big data analyses. These trainings have directly resulted in the completion of 3 integrated Masters degrees - Isobel Turnbull (2019 - first class), Hannah Flintham (2020 - first class & prize for best thesis), Elizabeth Newham (2020, upper second class)
 
Description Masters thesis research training
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Influenced training of practitioners or researchers
Impact MSc student (Mikaela Moore) acquired research training, and valuable transferable skills in data handling, big data analyses, critical thinking and sicietific writing.
 
Description PhD Studentship - Joanna Ainsworth
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Influenced training of practitioners or researchers
 
Title 15N-experiments from COMICS 1+2 
Description Incubation experiments with 15N-labelled tracers were performed onboard the COMICS-1/2 cruises. GC-IRMS measurements performed in a shorebased laboratory (at QMUL) to obtain nitrogen cycling rates - ongoing. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? No  
Impact GC-IRMS measurements ongoing to obtain rates data from these experiments. 
 
Title Ammonium data from COMICS 1+2 
Description Ammonium data from ambient seawater and experiments with different particle fractions during COMICS 1/2 cruises 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? No  
Impact These data are used as first estimates of nitrogen remineralisation activity, and will be further used for detailed nitrification and ammonification rate calculations when GC-IRMS measurements have been performed on the parallel incubation experiments 
 
Title Molecular biological analyses for COMICS 1+2 
Description Metatranscriptomics and fluorescent in situ hybridisation analyses on samples collected from both COMICS cruises 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? No  
Impact COMICS-1 samples and subsequent analyses contribute to ongoing MSci thesis (Isobel Turnbull) 
 
Title Remineralisation experiments from COMICS 1+2 cruises 
Description Various incubation experiments with radioactive-labels were performed onboard the COMICS1/2 cruises. Data analyses ongoing. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? No  
Impact Results from these experiments contribute to a PhD research project (studentship tied to this project) - Joanna Ainsworth Additional contribution to an integrated Masters project - Isobel Turnbull 
 
Description BAS 
Organisation British Antarctic Survey
Country United Kingdom 
Sector Academic/University 
PI Contribution (1) Microbial community structure and activity measurements of various particle fractions, including metatranscriptomics and anaerobic respiration of particle-associated communities. (2) Impacts of differential nutrient remineralisation rates on the efficiency of the Biological Carbon Pump
Collaborator Contribution Zooplankton ecology
Impact Not yet
Start Year 2017
 
Description GC-IRMS analyses 
Organisation Queen Mary University of London
Country United Kingdom 
Sector Academic/University 
PI Contribution 15N-labelling experiments to decipher complex nitrogen cycling processes
Collaborator Contribution Expertise and access to GC-IRMS measurements
Impact 15N-rates data.
Start Year 2017
 
Description Heriot-Watt 
Organisation Heriot-Watt University
Country United Kingdom 
Sector Academic/University 
PI Contribution (1) Microbial community structure and activity measurements of various particle fractions, including metatranscriptomics and anaerobic respiration of particle-associated communities. (2) Impacts of differential nutrient remineralisation rates on the efficiency of the Biological Carbon Pump
Collaborator Contribution Collaborator on large grant project, particularly on primary production and on the nutrinent remineralisation experiments
Impact Not yet
Start Year 2017
 
Description NOC 
Organisation National Oceanography Centre
Country United Kingdom 
Sector Academic/University 
PI Contribution The NOC team is the leading research team of this large grant project. They contribute various aspects of the overall project - including the overall project coordination, organisation and logistics of cruises, and are responsible of various components of the project including particle fluxes, nutrient distribution, glider deployments and related measurements, overall data syntheses, as well as modelling at different scales.
Collaborator Contribution (1) Microbial community structure and activity measurements of various particle fractions, including metatranscriptomics and anaerobic respiration of particle-associated communities. (2) Impacts of differential nutrient remineralisation rates on the efficiency of the Biological Carbon Pump
Impact The first sampling cruise took place in November to December 2017.
Start Year 2017
 
Description cruise blog 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Blog posts during our first research expedition in November-December 2017
Year(s) Of Engagement Activity 2018
URL http://www.comics.ac.uk/blog