Controls over Ocean Mesopelagic Interior Carbon Storage (COMICS)

Lead Research Organisation: British Antarctic Survey
Department Name: Science Programmes


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.
Description Regional and inter-specific differences in the respiration rates of mesopelagic fish was found when comparing ETS derived respiration rates from the Scotia Sea and Benguela Current region. We find high variability between individuals of a given species, even for those of a similar size found at the same environmental temperature. This is likely related to differences in lifestyle, e.g. activity, feeding mode and body composition.

Further details: Allometric methods underestimate the respiration rates of mesopelagic fish in the Southern Ocean compared to estimates from electron transport system (ETS) activity measurements. This can result in large underestimations of the fish-driven respiratory flux, and thus the contribution of this to the mesopelagic carbon budget. Conversely, allometric methods performed more adequately when compared to measurements made in the Benguela Current region. Cold water regions (<5 °C) are poorly represented in the data used to define current empirically defined allometric equations, and may explain the poor fit of these equations to our cold water data.
Exploitation Route These results will allow better parameterisations of the flux of particulate organic matter to the ocean interior in Earth System Models. They also highlight the many functions of krill as (i) a major dietary item of Southern Ocean predators (ii) a harvested resource and now (iii) an important contributor to global biogeochemical cycles
Sectors Agriculture

Food and Drink


Description Science from COMICS has been conveyed to a young audience via a Frontiers for Young Minds paper. The paper describes how krill are responsible for large amounts of carbon being transported to the ocean interior, so mitigating the potential further build up of carbon dioxide in the atmosphere. The paper is accompanied by reviews from young readers.
First Year Of Impact 2020
Sector Environment
Impact Types Societal

Title Macrozooplankton and nekton vertical distribution and abundance at the sustained observation location P3 in the northern Scotia Sea (Southern Ocean) during November and December 2017 
Description Macrozooplankton and nekton were collected with a Rectangular Midwater Trawl 25 (RMT25) over several visits to the sustained observation location P3 (52.70 S, 40.26 W) in the northern Scotia Sea during November and December 2017. The work was carried out as part of the NERC Large Grant, COMICS (Controls on Mesopelagic Interior Carbon) on board the RRS Discovery (cruise DY086). The RMT25 net hauls sampled between 10 and 500 m depth, with the water column divided into 2 depth intervals (10-250 m and 250-500 m). A total of 6 hauls were obtained during 3 separate visits to station P3, each visit comprising a pair of hauls, of which one was carried out in nominal daytime and the other in nominal nighttime. Catches were immediately sorted on board and identified to the lowest taxonomic level feasible. Subsamples of the catches were retained, principally for subsequent biochemical and physiological analyses. In total, 777 fish were caught, belonging to at least 23 species, with catches dominated by the myctophids Krefftichthys anderssoni, Gymnoscopelus braueri, Electrona antarctica and Protomyctophum tenesoni. The water column below 250m was dominated by Bathylagus spp. Temperate myctophid species, such as Protomyctophum parallelum and Protomyctophum andreyeshevi were also caught in small numbers. With regards macrozooplankton, the 250m-500m depth interval was dominated by the jellyfish, Atolla and Periphylla. The tunicate Salpa thompsoni and the euphausiids Euphausia triacantha and Thysanoessa spp. were also relatively abundant. Jellyfish still dominated catches in shallower waters (250m-10m), closely followed by euphausiids and Salpa thompsoni and chaetognaths. Themisto gaudichaudii and Parandania boecki were the most numerous amphipod species caught. Decapods were only caught in the deeper depth interval, both day and night. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Title Macrozooplankton and nekton vertical distribution and abundance in the Benguela Current region, May-June 2018 
Description Macrozooplankton and nekton were collected with a Rectangular Midwater Trawl 25 (RMT25) at locations within the Benguela Current region in May and June 2018. The work was carried out as part of the NERC Large Grant, COMICS (Controls on Mesopelagic Interior Carbon) on board the RRS Discovery (cruise DY090). Depth-discrete samples were collected across four time stations (BS1, BN1-3) between 0-750 m at intervals of 750-500m, 500-250m, 250-125m and 125-10 m. At each time station, two RMT25 hauls were deployed in the hours of darkness and two in daylight, with 16 deployments being undertaken overall. The RMT25 was operated via a downwire net monitor and was equipped with a flow meter, and temperature and salinity sensors. Nets in the deep strata (750-500m and 500-250m) were sampled for approximately 40 mins. and nets in the shallow strata (250-125m, 125-10m) for approximately 20mins. Catches were immediately sorted on board and identified to the lowest taxonomic level feasible. All fishes and subsamples of the other parts of the catch were retained (frozen), principally for subsequent biochemical and physiological analyses. In total, 1917 fish were caught and preserved (not including Cyclothone spp.). Catches were dominated by the myctophids and various other mesopelagic fish species. The water column below 250m was dominated by Bathylagus spp. and genus Melamphidae spp. The most numerous fish overall were the Cyclothone spp. which occurred in large numbers below 500m. In deeper depth intervals (250m-750m), the macrozooplankton component of the RMT25 net catches was mostly dominated by Decapoda and hydromedusae of the genus Atolla spp.. Salps, smaller hydromedusa species and small euphausiids Euphausia hanseni and Nematocelis megalops dominated the shallower depths (10-250m). 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes