The Ross Sea, a globally important ecological hotspot, hosts 25-45% of the world populations of Adélie and emperor penguins, South Polar skuas, Antarctic petrels, and Weddell seals. It is also one of the few marine protected areas designated within the Southern Ocean, designed to protect the workings of its ecosystem. To achieve that goal requires participation in an international research and monitoring program, and more importantly integration of what is known about these mesopredators, which is a lot, and the biological oceanography of their habitat, parts of which are also well known. The project will acquire data on these species' food web dynamics through assessing of Adélie penguin foraging behavior, an indicator species, while multi-sensor ocean gliders autonomously quantify prey abundance and distribution as well as ocean properties, including phytoplankton, at the base of the food web. Additionally, satellite imagery will quantify sea ice and whales (competitors) within the penguins' foraging area. Seasoned researchers and students will be involved, as will a public outreach program that reaches >200 school groups per field season, and >1M visits to the website of an ongoing, related project. Lessons about ecosystem change, and how it is measured, i.e. the STEM fields, will be emphasized. Results will be distributed to the world science and management communities.

We all love the idea of having a robot to do our bidding. Scientists are realising that robot technology now offers exciting possibilities to observe our environment in ways we have only dreamt of. We will use a fleet of three robots roaming the ocean near Antarctica to answer science questions that are critical to our ability to predict and manage the ocean and its living resources in an era of unprecedented change. The robots we will use are called ocean gliders. Much like the familiar airborne gliders, they do not have a propeller. Batteries drive a pump to move fluid between one area within the glider and another outside its hull, thus changing whether the glider is denser than seawater, so it sinks, or less dense than seawater, so it rises to the sea surface. It glides up and down, communicating via mobile phone with the scientists controlling it each time it comes to the surface. Oil prices have risen sharply in recent years, and ships use a great deal of oil. Using gliders as part of our future ocean and climate observing systems will save tax-payers' money since some ocean observations can be done much more efficiently by remotely controlled gliders. Gliders can also observe the ocean when we'd really rather not be there with ships, such as in winter or in strong winds and heavy seas. This project plans to show that these possibilities are within our grasp. We have assembled a multidisciplinary team of scientists who together are grappling with puzzles about how the ocean system works around Antarctica. Dense cold water sinks around the continent of Antarctica when cold wind blows over the water and helps sea ice to form. We've known for nearly 100 years that this happens in the southern Weddell Sea. We think that this might now be happening in a new region, because of the recent collapse of the Larsen Ice Shelf. Our gliders will measure the amount of dense water spilling off the continental shelf. This is important because climate models suggest that the amount and properties of this dense water are likely to impact on the global ocean overturning circulation that controls our climate; we need to know if these are changing. This dense water spilling over the continental slope probably also affects where the ocean currents are. So these currents might be moving further onshore or offshore, as the dense water changes. We'll try to measure and understand this. These changes in the ocean currents also affect the animals living in the waters near Antarctica. Krill are shrimp-like creatures that form the prey for animals such as whales, seals and penguins, not to mention underpinning a multi-million pound krill fishing industry (ever had a krill pizza?). Krill lay their eggs around the Antarctic Peninsula, and are then carried across the Scotia Sea to South Georgia by the ocean currents. Whilst the west Antarctic Peninsula is well surveyed, we don't know how many krill are in the Weddell Sea, on the eastern side of the Peninsula, possibly spending the winter under sea ice. Might the changes in ocean current affect whether these krill reach South Georgia? If we can establish that the krill are surviving under the ice and could travel to South Georgia, it may be that marine mammals and the krill fishing industry will be less vulnerable to climate change than we have feared. In which case, krill may become a more important food resource for us humans too in an uncertain future; you never know, the krill pizza may find its way to your local supermarket before long!

The Amundsen Sea hosts the most productive polynya in coastal Antarctica, with its vibrant green waters visible from space, and an atmospheric CO2 uptake flux density 10x higher than average for the Southern Ocean. The region is vulnerable to climate change, with rapid losses in sea ice, episodic shifts in the coastal icescape, and the fastest melting glaciers in the adjacent West Antarctic Ice Sheet (WAIS). In an ecosystem experiencing such dramatic change, it is critical to resolve the climate-sensitive drivers and feedbacks of the meltwater-associated iron (Fe) delivery, which underpins productivity in this otherwise high-nutrient, low chlorophyll region. Our previous field research (ASPIRE) identified a clear link between the melting WAIS and the delivery of micronutrient Fe to the polynya ecosystem, and its role in rapid CO2 drawdown. Our recent numerical modeling effort (INSPIRE) suggests several pathways for Fe delivery, ways to optimize fieldwork, and guidance for improving mechanistic understanding of Fe supply and cycling. An ongoing physical oceanographic field program (TARSAN, part of the International Thwaites Glacier Collaboration, ITGC) offers an ideal physical framework for our next research effort. We propose here to collaborate with TARSAN-supported UK scientists, providing significant value added to both teams. TARSAN explored the eastern Amundsen Sea by ship in Feb-Mar 2019 and expects to operate in the Thwaites region again in Feb-Mar 2021. They will use a full suite of physical oceanographic techniques, including 2 under-ice-shelf AUVs, gliders, surface vehicles, a microstructure profiler, shipboard CTD, seal tags, noble gases, and underway sensors to characterize the ice-ocean interactions responsible for rapid glacial melting. During 2019, TARSAN and THOR (also ITGC) collected detailed bathymetric, sedimentary, and ice-shelf cavity information (available Sept 2019) that will immediately improve and update the INSPIRE model to present-day boundary conditions. Our combined NSFGEO-NERC project (ARTEMIS) will facilitate collaboration between ASPIRE/INSPIRE team members and TARSAN/ITGC, add biogeochemical measurements to the funded 2021 expedition, and build on existing glider infrastructure and seal tag expertise (adding biogeochemical sensors to autonomous vehicles) at modest additional logistical cost. Numerical runs with ARTEMIS's updated model will inform TARZAN's 2021 field effort. Observations made will improve our understanding and our model, allowing a more sophisticated assessment of the role of Fe in present and future scenarios. Our team (ARTEMIS) would add shipboard biogeochemical observations (trace metals, carbonate system, nutrients, organic matter, microorganisms) and autonomous vehicle biogeochemical observations (nitrate, Chl a, optical backscatter) to gather knowledge critical to understanding the impact of WAIS melting on both the polynya ecosystem and the regional carbon (C) cycle. ARTEMIS combines the expertise of a US component comprising a carbonate system and microbial ecologist (Yager), a trace metal biogeochemist (Sherrell), a trace metal isotope geochemist (Fitzsimmons), an organic geochemist (Medeiros), an ice-ocean-atmosphere interactions expert (Stammerjohn), and a numerical ocean modeler (St-Laurent), with a UK component comprising 3 physical oceanographers: TARSAN lead PI (Heywood), a biogeochemically savvy autonomous vehicle expert (Queste), and an oceanographer whose vehicles are marine mammals (Boehme). This international team will work together at sea and with shore-based analyses to address a set of interconnected questions arising from the findings of ASPIRE/ INSPIRE.

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.

The balance between the production of organic carbon during phytoplankton photosynthesis and its consumption by bacterial, zooplankton and phytoplankton respiration determines how much carbon can be stored in the ocean and how much remains in the atmosphere as carbon dioxide. The amount of organic carbon stored in the ocean is as large as the amount of carbon dioxide in the atmosphere, and so is a key component in two global carbon cycle calculations needed to avoid a global temperature rise of more than 1.5 degrees C: the calculation of the technological and societal efforts required to achieve net zero carbon emissions and the calculation of the efficiency of ocean-based engineering approaches to directly remove carbon dioxide from the atmosphere. Yet, despite its vital role, our ability to predict how ocean carbon storage will change in the future is severely limited by our lack of understanding of how plankton respiration varies in time and space, how it is apportioned between bacteria and zooplankton and how sensitive it is to climate change-induced shifts in environmental conditions such as increasing temperature and decreasing oxygen. This woeful situation is due to the significant challenge of measuring respiration in the deep-sea and the uncoordinated way in which these respiration data are archived. This project will directly address these two problems. We will take advantage of our leadership and participation in an international programme which deploys thousands of oceanic floats measuring temperature, oxygen and organic carbon in the global ocean, in an international team of experts focused on quantifying deep-sea microbial respiration, and our experience of collating international datasets, to produce an unprecedented dataset of bacterial and zooplankton respiration. We will derive estimates of respiration based on data from floats, so that together with estimates derived from recently developed methods including underwater gliders, the new database will include respiration measurements calculated over a range of time and space scales. Crucially, respiration rates will be coupled with concurrent environmental data such as temperature, oxygen and organic carbon. This dataset will enable us to quantify the seasonal and spatial variability of respiration and derive equations describing how respiration changes with the proportion of bacteria and zooplankton present and with the chemical and physical properties of the water. These equations can then be used in climate models to better predict how respiration and therefore ocean carbon storage will change in the future with climate-change induced shifts in temperature, oxygen, organic carbon and plankton community. We will take part in a hybrid hands-on and online international training course on observations and models of deep-water respiration targeted to early career researchers from developing and developed countries to showcase the useability of the respiration database and the global array of oceanic floats. We will also prepare Science Festival exhibits on observing life in the deep ocean for schoolchildren. The deliverables of the project - a unique global open-access database of respiration measurements, new equations describing the sensitivity of respiration to changing temperature and oxygen suitable for climate models and online training materials for early career researchers - are of benefit to scientists who aim to predict how a changing climate will affect the storage of carbon in the ocean, educators who train the next generation of ocean scientists and practitioners, policy makers who need to quantify nationally determined contributions to actions limiting global warming, and scientists, engineers, lawyers, governing bodies and commercial companies designing, evaluating and implementing ocean-based carbon dioxide removal technologies.