Science in Progress
Ross Ice Shelf Programme
Surprisingly little is known about the Ross Ice Shelf despite it being the largest ice shelf on the continent. An improved understanding of ice shelf dynamics and likely response to a warming climate is critical to forecasting the future of the planet. The Ross Ice Shelf is a floating extension of the Antarctic Ice Sheet, and a large programme of work initiated in 2014 is seeking to understand its many complexities.
Dr Wolfgang Rack from the University of Canterbury and colleagues have been investigating the influence of the tide in causing the ice sheet to flex and bend. His team have developed improved technology for measuring the position of the grounding zone – the transition between the grounded ice sheet and the floating ice shelf - and discovered that this area is highly dynamic due to the influence of tides.
An NZARI-funded programme led by Dr Christina Hulbe (University of Otago) is proposing to drill through the ice shelf and into the sediment below, in order to determine how stable the Ross Ice Shelf has been over geological time. This programme involves a number of international collaborators and involves significant development of technology to enable the drilling to be successful. The field programme began in 2015/16 with the identification of suitable sites for future drilling, some 300km south of Scott Base.
A research team led by Dr Huw Horgan (Victoria University of Wellington) travelled to the Siple Coast, 1000 km from Scott Base, to examine the transition between the Kamb Ice Stream and the Ross Ice Shelf. This team is particularly interested in the role that sediment build up at the grounding zone and subglacial water flow plays in ice sheet stability. A range of seismic, radar and global positioning system (GPS) surveys were conducted to understand processes on the underside of this thick extent of ice.
Cape Adare, the northernmost land in the Ross Sea region, is expected to be one of first places to feel and respond to the effects of a changing environment. NZARI, in collaboration with researchers from the universities of Otago, Canterbury and Waikato, NIWA and the Korean Polar Research Institute, has been investigating the feasibility of conducting a long term ecological research and monitoring programme at this site. Cape Adare stretches some 40km beyond the Antarctic Continent across the continental shelf. It is flanked to the east by the northern Ross Sea and to the west by Robertson Bay. Cape Adare is an ideal monitoring and observation point to understand the impact of warm ocean and climate propagating into Antarctica from the Southern Ocean.
The first stage of the Cape Adare Pilot Study was completed early in the 2015/16 season. The team, led by Professor Gary Wilson, tested the feasibility and potential environmental impact of establishing a field camp at the site, which is home to one of the largest Adélie penguin colonies on the continent. Despite extreme weather conditions, the team collected marine environmental data, samples and underwater photos, serviced the weather station, conducted surveys on land and water and surveyed the penguin colony. Early indications are that Cape Adare and nearby Robertson Bay have strong connections to the Southern Ocean and will provide an unparalleled opportunity to measure the changing impacts on Antarctica from the ocean and climate systems to the north. Work will continue in the coming year, focussed on retrieval of scientific monitoring equipment and downloading of weather stations.
Past Antarctic Climate - Future Implications Programme
Scientists from GNS Science, Victoria University of Wellington, the University of Otago, NIWA and the University of Canterbury are examining the effect of climate warming on Antarctica’s ice sheets, led by Dr Richard Levy. A state-of-the-art drill system is being used to core frozen sediments that were originally deposited in front of and beneath land-based glaciers in the Friis Hills, Transantarctic Mountains. These sediments contain climate clues from a period in Earth’s past when atmospheric carbon dioxide concentrations were similar to those predicted for the coming decades and average surface temperature was 3-4 degrees warmer than today. These geological records provide insight into possible future response of Antarctica’s ice sheets and glaciers to current climate change. New findings will be fed into computer models that allow the team to simulate ice sheet response to a range of future climate scenarios. The approach will allow the rate and magnitude of sea level rise to be better predicted, which has direct implications for New Zealand.
Evidence-Based Risk Assessment & Human Impacts of the McMurdo Dry Valley Ecosystem
The McMurdo Dry Valleys have been a focus of research since the early explorers, and there are ongoing concerns about the impact of human activity on the fragile landscapes and ecosystems. This programme aims to deliver objective, evidence-based planning and management tools for the region to ensure that New Zealand remains an international leader in environmental management. A diverse range of scientific approaches are employed including field and laboratory-based analyses, experimentation, remote sensing and climate and ecological modelling. The programme is led by Professor Craig Cary, involves researchers from the University of Waikato, University of Canterbury and a number of international collaborators, and is funded primarily by the Ministry for Business, Innovation and Employment and the National Science Foundation (USA).
Marine Ecosystem Research
Understanding the life history of Antarctic toothfish is a critical as a basis for managing the fishery for this species in the Ross Sea. A team of fisheries scientists , led by Dr Steve Parker (NIWA) is using ship- and ice-based methods to improve knowledge of their movement, growth, breeding and feeding, and also to better understand how this large fish fits into the Ross Sea food web.
Scientists are working to determine how resilient Antarctic marine species and ecosystems will be to future changes such as warming and acidifying water. Associate Professor Miles Lamare (University of Otago) and colleagues is working with a common starfish to see whether the ability to cope with changing environmental conditions can be inherited from one’s parents. A team of scientists led by Dr Drew Lohrer (NIWA) will be taking a more holistic view to resilience by looking at the ability of coastal marine ecosystems to withstand or adapt to environmental change.
Despite Antarctica being a long way from sources of anthropogenic emissions, airborne contaminants such as methyl-mercury find their way to the poles, and are incorporated into the food chain. Dr Phil Lyver (Landcare Research) and his collaborators seek to understand the risk of mercury exposure for top predators in the Ross Sea. They are investigating the uptake of mercury by penguins, and whether this differs among species, with age or among colonies. At Cape Adare, the feeding behaviour of Adelie penguins is being uncovered with the aid of “splash tags” that record the diving profiles and range of individual penguins.
Sea Ice Programme
Antarctic sea ice is a key element in the global climate system. Its presence maintains cold conditions that help sustain Antarctica’s ice sheets, it modifies storms in the Southern Hemisphere, and it affects the rate of global warming by influencing ocean heat uptake in the Southern Ocean. Yet some of the observed behaviour of sea ice around Antarctica is not captured by existing Earth System Models. Using an airborne electromagnetic device (the EMBird) slung below a DC3 aircraft this team, will map the influence of ice shelf-affected waters on coastal sea ice by measuring snow and sea ice thickness in the western Ross Sea. The team, led by Professor Pat Langhorne and Dr Natalie Robinson will also be on the ice, linking these measurements to the snow and sea ice properties and the near-surface oceanography. In collaboration with a 2017 US icebreaker cruise, these targeted observations will contribute to a new sea ice module within the New Zealand Earth System Model. The programme is part of the Deep South National Science Challenge and has also attracted support from the Marsden Fund.