(BioMed Central press release, 29 January 2012) -- Killer whales (Orcinus orca) are the top marine predator, wherever they are found, and seem to eat everything from schools of small fish to large baleen whales, over twice their own size. The increase in hunting territories available to killer whales in the Arctic due to climate change and melting sea ice could seriously affect the marine ecosystem balance. New research published in BioMed Central's re-launched open access journal Aquatic Biosystems has combined scientific observations with Canadian Inuit traditional knowledge to determine killer whale behaviour and diet in the Arctic. Orca have been studied extensively in the northeast Pacific ocean, where resident killer whales eat fish, but migrating whales eat marine mammals. Five separate ecotypes in the Antarctic have been identified, each preferring a different type of food, and similar patterns have been found in the Atlantic, tropical Pacific, and Indian oceans. However, little is known about Arctic killer whale prey preference or behaviour.

Traditional Ecological Knowledge (TEK) is increasingly being used to supplement scientific observations. Researchers from Manitoba visited 11 Canadian Nunavut Inuit communities and collated information from over 100 interviews with hunters and elders. The Inuit reported that killer whales would 'eat whatever they can catch', mainly other marine mammals including seals (ringed, harp, bearded, and hooded) and whales (narwhal, beluga and bowhead). However there was no indication that Arctic killer whales ate fish. Only seven of the interviewees suggested that killer whales ate fish, but none of them had ever seen it themselves.

Tagged: Arctic, News, Polar research: Reports and findings

(U.S. Department of the Interior, U.S. Geological Survey press release, 23 January 2012) -- Denver, CO - A pioneering airborne electromagnetic survey in the Yukon Flats near Fort Yukon, Alaska, by the U.S. Geological Survey has yielded unprecedented images of the presence and absence of permafrost to depths of roughly 328 feet. The airborne survey captured images of permafrost over a substantially larger area, and with greater data density, than has been previously achieved using sparse boreholes and ground-based geophysics.

"Liquid water conducts electricity better than ice," explained USGS director Marcia McNutt. "We can detect from the air the weak magnetic fields generated by those electric currents, thus distinguishing quickly and easily melted from frozen ground. This new technology, and the maps of changing permafrost, will be valuable for both climate change research and engineering in the challenging Alaskan environment." Because the Yukon Flats is near the boundary between continuous permafrost to the north and discontinuous permafrost to the south, it is an important place to study permafrost dynamics.

Dr. Burke Minsley, geophysicist in the USGS’ Crustal Geophysics and Geochemistry Science Center in Denver and lead author of the study in Geophysical Research Letters, and his team surveyed more than 116 square miles centered 140 miles northeast of Fairbanks. Their data not only capture in detail the distribution of permafrost and its relation to surface- and groundwater features, but also the legacy of the Yukon River lateral migration over a period of roughly 1,000 years as manifested as a thawed region of permafrost.

Knowledge of the current permafrost distribution is critical for analyses designed to evaluate hydrologic and ecologic consequences of climate warming. It also provides a baseline for future investigation of the dynamic evolution of permafrost systems. In addition, the study is important because it presents a methodology for assessing permafrost not only in Alaska but throughout sub-Arctic and Arctic regions.

Tagged: Arctic, News, Polar research: Reports and findings