Processes Influencing Carbon Cycling: Observations of the Lower limb of the Antarctic Overturning (PICCOLO)

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


The vast, remote seas which surround the continent of Antarctica are collectively known as the Southern Ocean. This region with its severe environment of mountainous seas, winter darkness, strong winds, freezing temperatures and ice is unsurprisingly one of the least explored and under-observed parts of the global ocean. However, because of these extremes, it plays a large and still unquantified role in Earth's climate system. In this region, large amounts of heat and carbon dioxide are exchanged between the atmosphere and the ocean.

The physical mechanisms controlling these atmosphere-ocean exchanges are the subject of the NERC ORCHESTRA programme. We propose within PICCOLO to concentrate on the role that chemistry and biology play within those exchanges. In particular, PICCOLO will focus on understanding the mechanisms that transform the carbon contained in the seawater as it rises to the surface near Antarctica, interacts with the atmosphere, ice, phytoplankton and zooplankton inhabiting the near surface, before descending to the ocean depths.

PICCOLO will undertake an ocean research expedition to the region close to Antarctica, as computer models and satellite images show that these are areas crucial for carbon processes. Freezing seawater in these regions releases salt into the water below, making it denser and therefore causing it to sink. Strong winds cause the sea ice to be pushed away from the Antarctic coastline, leaving areas of open water called polynyas. Within the polynyas the water has enough light during the summer to allow phytoplankton to grow, as well as providing dense waters which sink to the deep, driving a giant ocean conveyor belt which has a large impact upon Earth's climate system.

The PICCOLO team will measure the key variables that control the biological and chemical processes in this region including iron, nutrients, phytoplankton and zooplankton. Crucially the team will study the controlling rate terms between different parts of this biological and chemical system. The PICCOLO team will make use of the latest technologies, including autonomous submarines, gliders and floats, to observe these processes in otherwise inaccessible and previously unstudied areas such as under the sea ice. Most ambitiously we will anchor a submarine to the seabed within a polynya and leave it over a winter season to collect data, recovering it the following spring. The PICCOLO team will put instruments on seals which will continuously take data as they dive up and down through the water, sending it back to scientists in real-time via satellite communication links.

This wealth of novel data will be analysed by the PICCOLO team, using state of the art computer models, to test our ideas about how the whole complex set of physical, chemical and biological processes affects carbon. Conceptually we will follow an imaginary parcel of water through the system looking at processes between the atmosphere and ocean, biological processes in the surface layer, exchanges between the upper and lower ocean and the final fate of the carbon.

The PICCOLO hypotheses address the following:

(i) Factors controlling the exchange of carbon dioxide between the ocean and atmosphere and the role of ultra-violet light in controlling the concentration of carbon dioxide in seawater;
(ii) The role of light, iron and nutrients in how carbon is processed by the plankton in the water;
(iii) The mediating processes governing the export of carbon from the upper ocean to depth;
(iv) The processes that take the carbon into the deep ocean on the next stage of its global journey.

Planned Impact

Here we summarise the non-academic communities who will benefit from this research project and how they will benefit. Please see the Pathways to Impact attachment for the activities we plan in PICCOLO in order to achieve this impact.

The main beneficiaries of data and knowledge from PICCOLO are:

i) Stakeholders and high level users of the Global Carbon Budget analysis will benefit through an improved product with PICCOLO biogeochemical observations being available for model evaluation and quantification of the ocean carbon sink via high-profile data synthesis products, such as the Global Ocean Data Analysis Project (GLODAP) and the Surface Ocean CO2 Atlas (

ii) The global earth system modelling community, and the users of such models such as governments, non-governmental organisations (NGOs), and the Intergovernmental Panel for Climate Change (IPCC), will benefit from the mechanistic understanding of carbon uptake processes in the Southern Ocean that PICCOLO will deliver, together with the roadmap for representing such processes in Earth system models. This will deliver a step-change in the quality of the projections undertaken by such models. The Hadley Centre at the UK Met Office will gain insight from PICCOLO, and we will work with them to assess the various NEMO-based models. The results of the project will aid the eventual parameterisation of carbon cycling processes for use in earth system models. The major results of PICCOLO will inform government policy with regard to the uncertainties in sea level rise predictions.

iii) Operational forecasters at global weather/climate services (such as the UK Met Office) and global navies will have free access to the near-real time (within hours of surfacing) temperature and salinity profiles from the Argo floats, gliders and seal tags, for assimilation into their operational forecast models. This will also benefit users of ocean reanalysis products that assimilate the PICCOLO profiles, since our targeted observational campaign location is a data desert.

iv) Those designing the global ocean (and climate) observing systems will benefit from PICCOLO. Our novel observational techniques will allow us to feed into the Southern Ocean Observing System (SOOS) design in order to design effective long-term measuring systems in the most useful locations. We will engage with the SOOS community through the Scientific Committee for Antarctic Research (SCAR).

v) The western and central Weddell Sea is very poorly sampled compared with the rest of this sector and the size of the krill stocks within it will be of interest to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). The krill fishery in the Southwest Atlantic sector has expanded and there is a clear need for better understanding of the spatial scale of the exploited stocks. ICED (Integrating Climate and Ecosystem Dynamics) is an international multidisciplinary regional programme within the SCOR/Future Earth sponsored IMBER (Integrated Marine Biogeochemistry and Ecosystem Research) project, launched to develop integrated circumpolar analyses of Southern Ocean climate and ecosystem dynamics.

vi) PICCOLO will nurture and train early career scientists, giving them skills to equip them for a productive independent career and to meet national skills shortages.

vii) The general public and young people in particular will gain from PICCOLO outreach. We aim to interest more young people in science and in higher education, raise awareness of global change and polar processes, and attract more people to careers in scientific research. We will target deprived areas such as Great Yarmouth in Norfolk and Plymouth in Devon, where young people's aspirations and achievements are below the national average and where inspiration into education may make a difference.


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Title OPIC, Oceanogaphic Plastic Incubator Chamber 
Description We designed and customized a in situ plastic incubator to to investigate plastic degradation in the southern ocean and Mediterranean Sea. OPIC consists of a frame containing a motorised rotating stage with transparent tubes sub-assemblies where reference plastic materials are incubated and exposed to natural weathering conditions for defined time periods up to 3 years. OPIC has been designed, tested and adapted for deployment with mooring line platforms in the open ocean and remote environments at different depths. This equipment will allow us to examine and measure different markers of plastic aging in situ for the first time, with high temporal and spatial resolution. 
Type Of Material Improvements to research infrastructure 
Year Produced 2022 
Provided To Others? No  
Impact Data collected through OPIC will provide new insights into the multiple and locally driven dynamics regulating plastic transformations and fate at sea. This is the first instrument able to investigate in situ degradation of mesoplastic in deep oceanic environment. 
Description investigation of biosilica flux 
Organisation Italian National Research Council
Country Italy 
Sector Public 
PI Contribution Increase of networking, access to the data from the mooring platform to compare with other region in the southern Ocean where the partner have mooring deployed
Collaborator Contribution Italian Polar Institute, Bologna, Italy. The Institute will provide Kind in contribution of Silica particulate analysis of the samples collected from the sediment and floating traps
Impact Access to the Italian research cruise in the Ross sea (2025-2026) Analyses of sample for biosilicate
Start Year 2024
Description COP26 activity on the SDA research vessell 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact During the COP26 event a member of BAS PICCOLO team spoke to people on the Sir David Attenborough about carbon flux and importance of biology for climate.
Year(s) Of Engagement Activity 2021
Description Member of Joint Exploration of the Twilight Zone Ocean Network (JETZON) Working Group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact JETZON focuses on the ocean region spanning globally from 200m to 1000m depth. This contains the largest and least exploited fish stocks of the world's oceans. The Twilight Zone also plays a major role in global chemical cycles and the storage of carbon dioxide. However, it is poorly understood. The Twilight Zone is under multiple stresses, including fishing, deep-sea mining, climate change and proposed carbon dioxide mitigation methods. With the majority of the Twilight Zone outside national boundaries, its size and inaccessibility means that its study is only possible through coordinated international action. Out of sight but not out of mind, JETZON will provide the knowledge necessary for s sustainable approach to the vast realm of the ocean's Twilight Zone.
Year(s) Of Engagement Activity 2021
Description Partecipation to OCEAN DECADE WG " A Helthy and Resilient Ocean" 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact The working group meet together to focus on the research/logistical and communication priority challenges in the frame of the Southern Ocean task force Action plan development
Year(s) Of Engagement Activity 2021
Description Partecipation to the Ocean Decade WG A productive Ocean" 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact The working group meet to agree on priority action to include int he future Southern ocean Action plan in order to achieve a Productive Ocean in the frame of the Southern Ocean decade vision
Year(s) Of Engagement Activity 2021
Description School Visit (Wales) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Talk provide at the following schools:
May 2021 - marine park first school - year 1 (5 year olds)
March 2022 - Llantwit Major School - sixth form
on how develop a careers as polar scientist
During the talk the kids were involved in an interactive discussion on the topic of Carbon export and climate change in the Southern Ocean
Year(s) Of Engagement Activity 2021,2022