ChAOS will quantify the effect of changing sea ice cover on organic matter quality, benthic biodiversity, biological transformations of carbon and nutrient pools, and resulting ecosystem function at the Arctic Ocean seafloor. We will achieve this by determining the amount, source, and bioavailability of organic matter (OM) and associated nutrients exported to the Arctic seafloor; its consumption, transformation, and cycling through the benthic food chain; and its eventual burial or recycling back into the water column. We will study these coupled biological and biogeochemical processes by combining (i) a detailed study of representative Arctic shelf sea habitats that intersect the ice edge, with (ii) broad-scale in situ validation studies and shipboard experiments, (iii) manipulative laboratory experiments that will identify causal relationships and mechanisms, (iv) analyses of highly spatially and temporally resolved data obtained by the Canadian, Norwegian and German Arctic programmes to establish generality, and (v) we will integrate new understanding of controls and effects on biodiversity, biogeochemical pathways and nutrient cycles into modelling approaches to explore how changes in Arctic sea ice alter ecosystems at regional scales. We will focus on parts of the Arctic Ocean where drastic changes in sea ice cover are the main environmental control, e.g., the Barents Sea. Common fieldwork campaigns will form the core of our research activity. Although our preferred focal region is a N-S transect along 30 degree East in the Barents Sea where ice expansion and retreat are well known and safely accessible, we will also use additional cruises to locations that share similar sediment and water conditions in Norway, retrieving key species for extended laboratory experiments that consider future environmental forcing. Importantly, the design of our campaign is not site specific, allowing our approach to be applied in other areas that share similar regional characteristics. This flexibility maximizes the scope for coordinated activities between all programme consortia (pelagic or benthic) should other areas of the Arctic shelf be preferable once all responses to the Announcement of Opportunity have been evaluated. In support of our field campaign, and informed by the analysis of field samples and data obtained by our international partners (in Norway, Canada, USA, Italy, Poland and Germany), we will conduct a range of well-constrained laboratory experiments, exposing incubated natural sediment to environmental conditions that are most likely to vary in response to the changing sea ice cover, and analysing the response of biology and biogeochemistry to these induced changes in present versus future environments (e.g., ocean acidification, warming). We will use existing complementary data sets provided by international project partners to achieve a wider spatial and temporal coverage of different parts of the Arctic Ocean. The unique combination of expertise (microbiologists, geochemists, ecologists, modellers) and facilities across eight leading UK research institutions will allow us to make new links between the quantity and quality of exported OM as a food source for benthic ecosystems, the response of the biodiversity and ecosystem functioning across the full spectrum of benthic organisms, and the effects on the partitioning of carbon and nutrients between recycled and buried pools. To link the benthic sub-system to the Arctic Ocean as a whole, we will establish close links with complementary projects studying biogeochemical processes in the water column, benthic environment (and their interactions) and across the land-ocean transition. This will provide the combined data sets and process understanding, as well as novel, numerically efficient upscaling tools, required to develop predictive models (e.g., MEDUSA) that allow for a quantitative inclusion seafloor into environmental predictions of the changing Arctic Ocean.

Antarctic Bottom Water (AABW) is an important water mass in the cooling and ventilation of the World's deep ocean. One of the principal sources of AABW has its roots in the production of cold, dense water that results from wintertime sea-ice production over the continental shelf of the southwestern Weddell Sea. However, there remains great uncertainty about the processes controlling the initial import of the source waters onto the continental shelf, and the export of the dense waters from the shelf regime. The uncertainty results from the extremely challenging sea ice conditions existing in the southern Weddell Sea, especially during winter. Conditions in the area of interest during winter are exceptionally difficult for any ship-based work, and instruments deployed in the ocean during the rather less difficult summer months, and which are left to monitor the water properties over the Winter period, are vulnerable to dredging by passing icebergs. We will tackle the problem using a technology that has recently come of age. We propose to attach conductivity-temperature-deph (CTD) tags, miniaturised oceanographic instruments, to Weddell seals (Leptonychotes weddellii). The tags have a satellite transmitter that relays the oceanographic data collected during the seals' dives, together with the dive location. The tag is glued harmlessly to the animal's fur using standard marine two-component epoxy and comes off again during the annual moult about eleven months later. A pilot study undertaken by the British Antarctic Survey involved the tagging of four seals, three of which supplied over-winter datasets. Although the coverage was impressive from only three tags, emphatically confirming the practicality of the technique, the region of interest is nearly 500,000 km^2 in area and a comprehensive dataset requires substantially more tagged animals. We will tag 20 Weddell seals at the eastern end of the shelfbreak north of the Filchner-Ronne Ice Shelf during the late Austral summer of 2010/2011. The resulting dataset resulting from the animals' dives during the winter will give the most comprehensive picture to date of the ocean conditions over the southern Weddell Sea continental shelf. By mapping the temperature of the water near the sea floor we will determine the locations where dense waters leave the shelf, and the processes involved: either a direct flow down the slope under gravity, or initially mixing at the shelf edge with waters from off the shelf before descending down the slope. We will also be able to determine where the source waters come on to the shelf. Weddell seals are very accomplished divers, diving repeatedly for long periods and to depths regularly reaching the on-shelf seafloor. Among Antarctic seals, Weddell seals also inhabit the southernmost waters, and remain within the pack-ice in winter when the ice expands northward. These characteristics make Weddell seals ideally suited for the proposed study. Although primarily an oceanographic project, the movements and diving behaviour of Weddell seals is of great interest to seal biologists who wish to understand differing behaviours in different parts of Antarctica. These variations were ably demonstrated by the extraordinarily diverse behaviour of the animals tagged during the pilot, and by comparisons with previous tracking of this species in other parts of the Antarctic. The long-ranging movements displayed by some of the seals tracked during the pilot study are untypical for the species, at least at other Antarctic locations, and may be related to the local oceanographic conditions. It is widely recognised that multidisciplinary studies such as proposed here will provide us with the tools to better predict how the distribution, behaviour and ultimately population status may be affected by changing ocean and climate conditions.

Non-technical summary Calanoid copepods are key players in World's oceans. They are the largest constituent of oceanic zooplankton biomass and are a major link within global carbon cycles. In the North Atlantic and Arctic, calanoid copepods are a vital food for commercially important fish species such as cod, mackerel and herring. A key feature of many calanoid copepod life-cycles is a phase of overwintering at great depth, in a state analogous to hibernation. This increases their chances of surviving to the next season through avoiding predation at times when there is little else to be gained by remaining within the surface layers. A notable feature of calanoid copepods is that they contain exceptionally high amounts of fat (or lipid). The large lipid store is both a valuable energy reserve and a major determinant of buoyancy. The attainment of neutral buoyancy is important to copepods over winter since they must minimise swimming effort in order to save energy. A balance must be sought between provisioning for the winter without disturbing the ability of the copepod to achieve neutral buoyancy. The best scientific efforts at trying to simulate this balance have so far proved to be unsatisfactory. Recently, two potential additional mechanisms of buoyancy control have been identified. In one study, Sartoris and colleagues found that diapausing copepods contained a different balance of ions in their bodily fluids (haemolymph) compared to active, surface dwelling copepods. In a second study, scientists involved in the present proposal showed that lipids rich in omega-3 polyunsaturated fatty acids (PUFAs) changed from liquid to solid state when under pressures typical of the deep sea. The effect only happened when PUFAs comprised more than 50% of the lipid store which, coincidentally, was commonly found in deep diapausing copepods, but not in those still active at the surface. At present, both of the mechanisms have only been identified in Southern Ocean copepods, although previously 'misinterpreted' evidence in the scientific literature also suggests that northern hemisphere species employ similar techniques. We will carry out surveys across a number of locations in the North Atlantic, Arctic and adjacent sea-lochs to determine lipid composition and haemolymph-ion concentrations in three calanoid copepod species. The surveys take into account environmental influences, particularly the type and availability of the microplanktonic food of copepods. This will determine whether there is any active regulation of the levels of omega-3 fatty acids in the lipid stores. Such active regulation may be of particular importance towards the end of winter as a means of controlling the timing and rate of ascent back into the surface layers. Our sampling strategy, application of novel analytical techniques and datasets generated during the research will allow these questions to be addressed. Secondly, using statistical techniques we will reconsider efforts made so far to simulate overwintering depth and seek improvements through including additional data and mechanisms. For instance, in changing from a liquid to solid state, the volume occupied by a lipid will be decreased and its response to increasing pressure will change. The effects of ionic balance will also be considered, mainly in how it may assist copepods maintain their theoretical neutral buoyancy depth in the face of any physical disturbance. This research proposal is based on our recent discovery, that the biophysical properties of lipids are a major factor controlling the distribution of life in the oceans. This finding gives an exciting new perspective on the role of lipids in marine organisms, opening up a fundamentally new direction for research, with profound implications for our understanding of the entire ocean food web.

Mass extinctions in the geological record have shaped the course of evolution and life on Earth, and without them, humans would not exist. Understanding what causes mass extinctions is therefore one of the most fascinating topics for scientific research. We are still a long way from solving these ancient murder mysteries. By studying the cause and consequence of major changes in deep time, we can gain a unique perspective on current-day climate change and the issues affecting life on Earth. Two of the biggest extinctions ever to affect the Earth occurred within 10 million-years of each other, in the Middle Permian and at the Permian-Triassic (PT) boundary. The latter event killed up to 95% of marine species and is the greatest crisis of life in the geological record. Both extinctions are well-known from Permian equatorial regions, where their probable causes include volcanism, sea-level change, and oceanic oxygen depletion. However, little is known of the record of environmental or faunal change in mid-high latitudes, and it is not clear whether the causes of low-latitude losses were operating elsewhere. This project will test this by examining superb Permian sequences from the Arctic island of Spitsbergen, where marine rocks are exposed in cliffs that contain a record of faunal and environmental change. During the study interval, Spitsbergen was located at 40-60 degrees north, far removed from equatorial settings, in the Boreal seas. Study in the region has been hampered by an inability to accurately date the rocks. Thus, the relative age of events in the Boreal realm is unclear. The rocks are known to contain abundant fossils but their response to the two extinction events is unknown. Volcanism is thought to have caused the Middle Permian extinction in South China, but it is not clear if its effects reached beyond that continent. Warming and lack of oxygen in the oceans are factors in the PT event, but the cool waters of the Boreal seas ought to have been less susceptible (because oxygen is more readily dissolved at lower temperatures). Little is known of the recovery of the Boreal ecosystem between the two extinctions: did life recovery fully before being devastated at the PT boundary, or was that crisis so severe because the ecosystem was already stressed by the earlier event? An improved understanding of faunal loss and recovery in the region will help us to evaluate the competing extinction mechanisms. The correlation of the Boreal record with other parts of the world is integral to the success of the project, and will be achieved using chemostratigraphy. Thus, we will produce a carbon isotope curve - which has recently been established for other regions but not yet for Spitsbergen. The project will therefore: a) develop a Permian age model, allowing Spitsbergen sections to be correlated globally; and b) examine the record of environmental and faunal change within that time framework. To achieve the second objective, we will employ a variety of techniques: field- and microscope examination of fossils to pinpoint the timing of extinction and recovery; sequence stratigraphy (changes in rock type that reflect changing sea-levels); and analysis of pyrite in the rocks (to assess changes in oceanic oxygen levels). All of these methods have been used successfully before, but have never been applied to studies of the Boreal realm. Ultimately this project aims to identify two mass extinction events in the Boreal realm, and to ascertain their timing and causes. This will test whether the drivers of equatorial extinctions during the Permian can truly be considered global. The results will be publicised to a scientific audience through the academic press, and to a wider audience via the project website, school outreach activities, and the mass media.

Tracking wild animals, such as seabirds, poses substantial logistical difficulties as they often cannot be observed directly, meaning remote tracking technology is integral to the study of natural behaviour. GPS loggers, which store animals' position at fixed time intervals, are one of the most commonly used remote tracking devices. However, they present a significant cost-to-output trade-off. Affordable GPS tags collect data archivally, and so the animal must be recaptured to retrieve the tag its data. They are also limited in memory capacity and battery life, limiting study durations to 2-3 weeks maximum, and their consequentially large size can have significant impacts on normal behaviour for many species. More expensive devices overcome these problems by remotely communicating with satellites to download data to a server, but can cost hundreds or thousands of pounds per tag, limiting the number of individuals that can be tracked at once. Reverse GPS technology overcomes many of these limitations. Under this system, small, radio frequency-emitting tags are attached to animals, which communicate with nearby receiver stations to estimate and download the location of the tagged animal. These tags are very lightweight, not limited by memory, and have very low power consumption, and so can be used to tag many individuals at once, for long durations, and at a low cost. The ATLAS Wildlife Tracking System is a revolutionary reverse GPS system that has been used on a variety of study systems across the globe to remotely track many individuals simultaneously. We propose to install the first ATLAS system in the Arctic, and conduct a proof-of-concept test of its operationality. During this project, we will establish an ATLAS network of 6 base stations, giving coverage of a 26km2 area, encapsulating a kittiwake study colony and a large fraction of the Bijleveld fjord, at the base of which lies the Nordenskjöld Glacier. This glacier is an important foraging site, but is vulnerable to many of the effects of climate change in the Arctic, including sea surface temperature rises and Atlantification (whereby warmer and saltier water extends into the Arctic ocean, altering prey availability). We will fit 200 kittiwakes with tags, a substantial fraction of the colony, to examine to what extent environmental conditions reduce or exacerbate competition in the area, and how individuals respond. Once optimised, this system could be rolled out to multiple other species, giving a wholistic overview of movement and interactions in this ecosystem.