Expedition Search

NASA's P-3 Orion aircraft. Photo by Mark Buesing.

IceBridge, a six-year NASA mission, is the largest airborne survey of Earth's polar ice ever conducted. IceBridge uses a highly specialized fleet of research aircraft and the most sophisticated science instruments ever assembled to characterize yearly changes in thickness of sea ice, glaciers, and ice sheets in the Arctic and Antarctic. The research team will experience first-hand the excitement of flying a large research aircraft over the Greenland Ice Sheet. While in the air they will record data on the thickness, depth, and movement of ice features, resulting in an unprecedented three-dimensional view of ice sheets, ice shelves, and sea ice. Operation IceBridge began in 2009 to bridge the gap in data collection after NASA's ICESat satellite stopped functioning and when the ICESat-2 satellite becomes operational in 2016, making IceBridge critical for ensuring a continuous series of observations of polar ice. IceBridge flies over the Arctic and Antarctic every year — in the Arctic from March to May and the Antarctic in October and November. By comparing the year-to-year readings of ice thickness and movement both on land and on the sea, scientists can look at the behavior of the rapidly changing features of the polar ice and learn more about the trends that could affect sea-level rise and climate around the globe. More information about IceBridge can be found at the NASA project website. http://www.nasa.gov/icebridge

A Weddell seal meets a cameraman under the sea ice near McMurdo Station, Antarctica. Photo by Steve Rupp, Courtesy of Michael League.

Since the first expeditions to the poles, scientists have compiled a long list of polar taxa that have unusually large body sizes. This phenomenon is known as polar gigantism, and biologists have proposed many hypotheses to explain it. The most broadly-accepted idea is the ‘oxygen hypothesis,’ which states that polar gigantism stems from a combination of high oxygen availability in the ocean and low metabolic rates because of the extreme cold temperatures. In combination, these two factors are thought to allow animals to be giants by making it comparatively easy to get enough oxygen from the environment to support large bodies. The links between body size, environmental oxygen availability, and performance have been used to argue that as marine and aquatic environments warm, giants will be among the first to disappear. We are looking at these tradeoffs and the validity of the size-vulnerability hypothesis using Antarctic pycnogonids (sea spiders), which contain spectacular examples of polar gigantism. Visit the researcher's working group website to learn more information on this topic.

Pressure ridges form ice formations on the Ross Ice Shelf, Antarctica. Photo by Gary Wesche.

The objective of our project is to understand the behavior of the McMurdo Shear Zone (SZ) in Antarctica through a four year integrated study involving field observation, satellite remote sensing, and numerical modeling. The SZ is a section of heavily crevassed ice that separates the slow-moving McMurdo Ice Shelf (MIS) from the larger fast-flowing Ross Ice Shelf (RIS). Previous mapping of crevasses in the SZ indicates the potential for unstable behavior. Our project will carry out GPS surveys to study the surface deformation across the SZ and Ground Penetrating Radar surveys (GPR) to obtain detailed maps of crevasse extent and orientation. Because the shear zone is intensely crevassed, and hence dangerous for surface travel, we will perform the GPR surveys using an autonomous robot. The field observations will be used to develop a numerical model of the shear zone’s behavior and simulate future scenarios of its influence on ice shelf stability.

The SZ provides a critical amount of lateral support for the RIS. A potential weakening of this area could reduce the amount of backstress provided by the RIS on inland ice which would increase the flux of ice across the grounding line and thereby accelerate the ice sheet’s contribution to sea level rise. Logistic support of the US Antarctic Program’s South Pole station also relies on an overland traverse from McMurdo which must cross the SZ. Our work will provide a means of predicting future SZ behavior and provide a timeframe to plan alternative routes if necessary.

Sunrise over the Southern Ocean. Photo by Jillian Worssam.

This project focuses on an important group of photosynthetic algae in the Southern Ocean (SO), diatoms, and the roles associated bacterial communities play in modulating their growth. Diatom growth fuels the food web in the SO and balances atmospheric carbon dioxide by sequestering the carbon used for growth to the deep ocean on long time scales as cells sink below the surface. The diatom growth is limited by the available iron in the seawater, most of which is not freely available to the diatoms but instead is tightly bound to other compounds. The nature of these compounds and how phytoplankton acquire iron from them is critical to understanding productivity in this region and globally. The investigators will conduct experiments to characterize the relationship between diatoms, their associated bacteria, and iron in open ocean and inshore waters. Experiments will involve supplying nutrients at varying nutrient ratios to natural phytoplankton assemblages to determine how diatoms and their associated bacteria respond to different conditions. This will provide valuable data that can be used by climate and food web modelers and it will help us better understand the relationship between iron, a key nutrient in the ocean, and the organisms at the base of the food web that use iron for photosynthetic growth and carbon uptake.

A crack in the soil amid tundra plants near a thermokarst. Photo by Regina Brinker.

Below the surface of arctic tundra is a matrix of soil, roots, and fungal hyphae that may play a critical role in the trajectory of future climate change. For millennia arctic plants have persisted in cold, wet, and shallow soils underlain with permafrost, permanently frozen ground, in many regions of the Arctic. However, with unprecedented warming in the last century, these plants may see the amelioration of their harsh, belowground environment. With a warming climate, the depths to which permafrost soils thaw each summer increase, potentially providing greater access to drier and more nutrient rich soil resources. Yet, whether arctic plants and their obligate, fungal root-symbionts have the capacity to respond rapidly and exploit soil resources as frozen, high-latitude soils thaw is unknown. Our research investigates the opportunistic capacity of arctic plants and their fungal symbionts to explore a newly available soil environment. Our goal is to uncover the role that the belowground response to a warming world may play in mitigating feedbacks between thawing permafrost and the atmosphere.

The CiPEHR study site in early summer. Photo by John Wood.

The carbon cycle is the means by which carbon is moved between the world's soils, oceans, atmosphere, and living organisms. Northern tundra, permafrost, ecosystems play a key role in the carbon cycle because the cold, moist, and frozen soils trap organic material and slow their decomposition. This very slowly decaying organic material has caused carbon to build up in the Arctic during the past thousands of years. Historically, the tundra has stored large amounts of carbon because soil decomposition in permafrost was very slow. Now, warming in the Arctic is causing the permafrost to thaw and the tundra to become warmer and dryer. As the earth warms and permafrost thaws, this previously frozen carbon is released as carbon dioxide and goes into the atmosphere, turning the tundra into a source of carbon, rather than a sink. We are using carbon isotope techniques to measure how much carbon comes directly from soil decomposition and how much comes from plant respiration. This will help us understand more about the source/sink dynamics of the tundra. Little is known about respiration in the arctic winter, but our winter sampling is improving. With more data we will have a better idea of how much carbon is lost during the long, dark winter. Together our summer and winter data will help improve global carbon models by adding a more realistic representation of the Arctic. Because carbon dioxide is a greenhouse gas, any additional carbon dioxide lost from permafrost ecosystems creates a positive feedback that leads to even further warming.

More information about the project can be found here: https://www2.nau.edu/schuurlab-p/index.html

A thermokarst at Wolverine Lake, near Toolik Lake, Alaska. Photo by Lauren Watel.

Team Announcement: Due to unexpected circumstances, Ivy McDaniel will not be going to the field this season with the research team.

Tremendous stores of organic carbon frozen in permafrost soils have the potential to greatly increase the amount of carbon in the atmosphere. Permafrost soils may thaw sporadically and melting ground ice can cause land-surface sinking called "thermokarst failures". These failures change the rate and amount of carbon released with the unanticipated outcome being that soil carbon can be mixed-up from a depth and exposed to sunlight as the land surface is altered. Sunlight can photo-degrade or break-down organic carbon and alter the carbon's ability to support bacterial respiration to produce carbon dioxide. Whether sunlight and UV exposure will enhance or retard the conversion of newly exposed carbon to carbon dioxide is currently unknown—this study is providing the first evidence that this alteration will be amplified by photochemical processes and their effects on microbes.

The research team is trying to understand exactly how sunlight and bacteria degrade dissolved organic matter by determining how fast these processes convert newly released dissolved organic matter to carbon dioxide, compared to dissolved organic matter already in surface waters. The team is accomplishing their research objectives with a series of laboratory experiments to determine rates of photodegradation and microbial processing of dissolved organic matter from different sources, and a series of landscape comparisons and sampling transects to characterize dissolved organic matter degradation in small basins and large rivers extending from the headwaters to the Arctic Ocean. Ultimately, this research will attempt to answer questions such as whether carbon export from tundra to oceans will rise or fall and how reactive the exported carbon will be. The team hopes to be able to measure the ultimate impact of impending disturbances, including climate change, on the net carbon balance of the Arctic and its interaction with the global carbon cycle.

A ribbon seal on the Chukchi Sea. Photo by Andrea Skloss.

The Arctic Ocean is one of the most remote locations on Earth and the area where the impact of climate change may be most strongly expressed. In the Chukchi Borderlands (CBL) area, water masses from the Arctic, Pacific and Atlantic oceans meet and interact over tremendously complex bottom topography, creating intricate currents and sea ice drifts. It is also the region of the most dramatic summer sea ice meltdown in the last decades. This project is a multi-disciplinary group effort to explore marine communities from microbes to mammals and from sea ice to seafloor in this poorly known, bathymetrically and hydrographically complex Arctic region. We will use a combination of photographic mapping using ROV, physical sampling, and state-of-the-art metagenomics to assess the diversity of this region. Field work involves a ~30-day icebreaker cruise in the summer of 2016, with use of the ROV Global Explorer that provides unique opportunities to capture fragile pelagic organisms and observe benthic fauna in relation to the bathymetric and geomorphological features of the seafloor.

Peter Ganzlin and Bradi Jo Petronio at one of their moss plots. Photo by Mark Paricio.

The goal of our project is to understand how terrestrial ecosystems influence permafrost temperatures. There are places in the Arctic where climate is warming but permafrost temperatures are stable, while at other places permafrost temperatures are rising rapidly with climate. Soil and vegetation that sit on top of permafrost can either promote heat transfer or act as insulators. Our project will use field measurements at research sites throughout Alaska and Siberia to identify broad trends in relationships between ecosystems and permafrost temperature dynamics. At research sites in Siberia we will make detailed measurements to identify the processes responsible for these trends. This work will help to understand the effects of Arctic vegetation change on permafrost temperatures.

Samples are gathered to test the microbial community composition at Toolik Lake, Alaska. Photo by Lauren Watel.

Microbial diversity has recently been found to show a pattern of organization at various scales. The research team attempts to answer three basic questions about microbial diversity and dispersal, focused on the long-term aspects of dispersal events and climate change: 1) How does environment influence microbial community composition and rate of function? For example, how quickly they convert organic material to carbon dioxide. 2) How are distribution patterns of microbial communities in lakes, streams, and soils influenced by the dispersal from local water flow? 3) How are the shifts in microbial community composition related to shifts in environmental conditions over time such as those caused by climate change?