Expedition Search

The carbon cycle is the means by which carbon is moved between the world's soils, oceans, atmosphere, and living organisms. Northern tundra 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. Now warming in the Arctic is slowly 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. Because carbon dioxide is a greenhouse gas, this additional carbon dioxide creates a positive feedback that leads to even further warming.

Little is known about respiration in the arctic winter. The team used five different methods in hopes of finding the best way to measure how much carbon is being released from northern ecosystems in the winter. Measuring winter respiration directly from experimentally warmed plots and understanding the drivers of wintertime tundra respiration will have the added benefit of being able to improve global arctic carbon models. More information about the project can be found here.

A large international team of scientists and drilling technicians worked throughout the austral summer to continue testing with the world's largest scientific instrument, the in-ice IceCube Neutrino Detector. Neutrinos are incredibly common (about 10 million pass through your body as you read this) subatomic particles that have no electric charge and almost no mass. They are created by radioactive decay and nuclear reactions, such as those on the Sun and other stars. Neutrinos rarely react with other particles or forces; in fact, most of them pass through objects (like the earth) without any interaction. This makes them ideal for carrying information from distant parts of the universe, but it also makes them very hard to detect. All neutrino detectors rely on observing the extremely rare instances when a neutrino does collide with a proton. This collision transforms the neutrino into a muon, a charged particle that can travel for 5-10 miles and generate detectable light.

IceCube is located in Antarctica because the huge amount of dense ice under the South Pole contains many protons that can be hit by passing neutrinos, and the ice is transparent, so the resulting light can be detected by sensors. IceCube is made up of 4200 sensitive light detectors embedded in the ice at depths between 1450 and 2450 meters (4700-8000 feet). The sensors are deployed on "strings" of 60 modules each, into holes 60 cm in diameter in the ice melted using a hot-water drill. Encompassing a cubic kilometer of ice, IceCube expands on an existing experiment that started detecting neutrinos at the South Pole in 1997. When IceCube is complete, it may detect up to 300,000 neutrinos a year for up to 20 years.

The data collected will be used to make a "neutrino map" of the universe and to learn more about astronomical phenomena, like gamma-ray bursts, black holes, exploding stars, and other aspects of nuclear and particle physics. However, the true potential of IceCube is discovery; the opening of each new astronomical window has led to unexpected discoveries.

A small team of earth scientists and engineers used a specialized drill to reach buried ice deposits in the Dry Valleys region of Antarctica. Stagnant and/or slow-moving debris-covered glaciers may contain ice several million years in age. By comparison, the oldest ice yet cored from the East Antarctic Ice Sheet is approximately 1 million years old. As a result, these buried ice deposits hold an ancient archive of Earth's past atmospheric conditions. Each ice core enabled the research team to gain access to a reliable record of atmospheric and climatic change extending back for many millions of years, making it by far the oldest ice yet known on this planet.

In addition to drilling for ancient ice, the team worked in the Dry Valleys to seek a better understanding of surface processes that play a critical role in maintaining and/or modifying buried glacier ice. Despite their age and potential to register long-term climate change, there has been surprisingly little research on the geologic and geomorphologic processes that both preserve and modify debris-covered glaciers in Antarctica. In addition, the cold polar desert of the Dry Valleys is one of the most Mars-like climatic environments and landscapes on Earth, serving as a proxy for very ancient ice buried on Mars and providing insight into Martian history and the potential for life on Mars.

The purpose of the project was to monitor "space weather." Space weather encompasses phenomena that take place a few hundred miles above the surface of the Earth. This includes the ionosphere, the magnetic fields of the Earth and Sun, the northern and southern lights, and the solar wind. A high-latitude location (either north or south polar regions) is ideal for such monitoring because in these regions the field lines of the Earth's magnetic field become almost perpendicular to the Earth.

To do this, scientists created Automatic Geophysical Observatories (AGOs) that are active at five locations established across the Antarctic Plateau that house nearly identical instruments measuring atmospheric weather conditions. During their stay, the team made sure all of the different instruments were working properly and collecting reliable data. Supporting these observatories is crucial to the study of interactions between the magnetic fields of the Sun and of the Earth. Learning more can help us understand the potential disturbances in these fields that can disrupt radio communications or our power systems, and even take out satellites that orbit close to Earth.

This is the first of two research seasons in Antarctica for the WISSARD (Whillans Ice Stream Subglacial Access Research Drilling) project. The goal of the WISSARD Project was to learn more about the physical, chemical, and biological aspects of the unique environments under glaciers in West Antarctica. In addition to understanding the geology and hydrology, the team studied life in extreme subglacial environments. By investigating this interrelated system, they got a better understanding of the influence of climate change on the melting of ice sheets and their contributions to sea level rise.

The WISSARD Project had three inter-related components:

• RAGES (Robotic Access to Grounding zones for Exploration and Science)
• LISSARD (Lake and Ice Stream Subglacial Access Research Drilling)
• GBASE (GeomicroBiology of Antarctic Subglacial Environments)

The primary goal of the first field season was to test and explore the zone (grounding zone) just before the grounded ice of the Whillans Ice Stream went afloat into the Ross Ice Shelf, which is thought to be a very sensitive area in terms of ice sheet dynamics and its response to global warming. During their deployment, the team used a hot water drill to melt boreholes deep into the ice stream. After the holes were melted, they tested and deployed complex new monitoring and sampling equipment under the ice.

Learn more about the project at the official project website.

Antarctica plays a central role in global tectonic evolution. Competing theories have been put forward to explain the formation of the Transantarctic Mountains (TAMs) and the Wilkes Subglacial Basin (WSB), primarily due to a lack of information on the crustal thickness and seismic velocity of the areas. The research team attempts to resolve how the TAMs and WSB originated and how their formation relates to Antarctica’s geologic history. Since most of Antarctica is covered by large ice sheets, direct geologic observations cannot be made; therefore, “remote sensing” methods like seismology must be used to determine details about the earth structure.

The goal of this project, funded by the National Science Foundation, was to broaden our knowledge of geology in this region with a new seismic project; the Transantarctic Mountains Northern Network (TAMNNET), a 15-station array across the northern TAMs and the WSB that will fill a major gap in seismic coverage. Data from TAMNNET was combined with that from previous and ongoing seismic initiatives and was analyzed to generate an image of the seismic structure beneath the TAMs and the WSB.

While in the field, the team spent most of their time deploying seismic stations that compose the new TAMNNET array. This included loading equipment onto small airplanes, flying to remote field locations, digging large holes in the snow/ice to shelter the equipment, and assembling and testing the seismic hardware.

The Russian-American Long-term Census of the Arctic (RUSALCA) is a joint NOAA/Russian Academy of Sciences sponsored program whose mission is to document the long-term ecosystem health of the Pacific Arctic Ecosystem. Research cruises through the Bering Strait and Chukchi Sea in both U.S. and Russian waters provide the ability for sampling irrespective of political or exclusive economic zone boundaries.

These seas and the life within them are biologically rich and are thought to be particularly sensitive to global climate change because they are in areas where steep thermohaline and nutrient gradients in the ocean coincide with steep thermal gradients in the atmosphere. The Bering Strait acts as the only Pacific gateway into and out of the Arctic Ocean and as such is critical for the flux of heat between the Arctic and the rest of the world. One of the overall goals of the entire project was to monitor the flux of fresh and salt water in the region and to establish benchmark information about the distribution and migration patterns of the biologically rich life in these seas. Dr. Grebmeier's research on this final cruise of the project was particularly focused on benthic biological communities and their associated sediment chemistry.

The research team worked out of Barrow, Alaska at the juxtaposition of two Arctic seas; the Chukchi and Beaufort Seas. It is a region frequently traveled by the endangered bowhead whale. This project had its genesis in understanding why the region near Barrow, Alaska is a feeding hotspot for migrating bowhead whales. The whales and their prey will continue to be a focus of the team's interpretations. The research team conducted oceanographic sampling of the physical and biological marine environment in the region over the period 2005-2011 and observed significant inter-annual variability. Long-term studies of the ocean conditions in the Arctic are needed in order to understand how these environments vary inter-annually. The research team will continue to document conditions in the biological-physical ocean ecosystem, through annual boat-based surveys, in order to predict and understand the potential impacts of climate change on the Arctic ecosystem.

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Titulo financiado: Observación anual del medio ambiente marino biológico y físico en los mares Chukchi y Beauford en las cercanías de Barrow, AK.

El equipo de investigación viajará por avión a Barrow, una comunidad pequeña de aproximadamente 4,500 habitantes en la costa norte de Alaska. Como permitan las condiciones del tiempo, el equipo se embarcara para la colección de muestras oceanográficas a bordo del buque de investigación Annika Marie de 43 pies. Las actividades de a bordo incluirán colección de agua y plancton y mediciones de conductividad, temperatura, y profundidad. A bordo también tomarán nota sobre las ocurrencias de mamíferos marinos y realizarán el procesamiento preliminar de muestras. Si el clima es malo para navegar en el océano ellos pasarán el tiempo en Barrow catalogando muestras y organizándose para los días que pasaran sobre el agua.

The northern Chukchi Shelf receives large inputs of organic matter from the highly productive shelf regions of the North Pacific and from local sources of primary production, including algae in the ice and sediment and phytoplankton in the water column. As a result, highly productive biological "hotspots" have been documented in the vicinity of Hanna Shoal. Because of the biological significance of this region and its importance for oil and gas exploration and development, the team planned a multi-disciplinary investigation to examine the biological, chemical, and physical properties that define this ecosystem.

Previous work in the area has profiled the biogeochemistry of the northern Chuckhi Sea, but this study focused more particularly on the Hanna Shoal region, looking at phytoplankton and zooplankton in the open ocean as well as the physical oceanography through direct measurement of circulation, density fields, and ice conditions.

The team excavated portions of the Raven Bluff archaeological site, the remains of a prehistoric camp that date to the very end of the last ice age, about 10,000 years ago. The site in Northwestern Alaska is important because it contains the oldest well-preserved collection of archaeological animal bone in the American Arctic. The goal of this research was to gather information at the site that can teach us about what the people who occupied the Raven Bluff site ate; how they obtained, processed and stored their food; and how they manufactured their tools, clothing, and housing.

The site also contains fluted projectile points – a type of stone spear tip that is associated with many of the earliest archaeological sites in the continental United States. Fluted projectile points have been found throughout the Americas, but have never been reliably dated in Alaska. Because people migrated from north-to-south after entering the Americas from Asia across the Bering Land Bridge, fluted points in the far north are expected to be older than the fluted projectile points found in the continental United States. However, initial findings from Raven Bluff indicate that the fluted projectile points at this site are actually younger than the oldest fluted projectile points in the continental United States. By dating these artifacts, the research team is studying the nature and timing of early human population movements in the Americas.

In addition to providing information on early human settlement patterns, the animal remains from this site may shed light on the long term history of caribou populations in what is now the home of the western arctic caribou herd, a resource of critical importance to local residents and a key issue of concern for biologists and wildlife managers.