Research press release


Nature Communications

Geoscience: What L-ice beneath...



今回、Jill Mikuckiたちは、ヘリコプターに搭載した電磁センサーを用いて、マクマードドライバレーの地下に存在する物質の温度と水分含量のマップを作成した。その結果、マクマードドライバレーは氷で固められているのではなく、氷点よりかなり低いが、微生物の生息に適した温度の塩水による地下水網を有していることが明らかになった。


Large bodies of salty water potentially capable of hosting microbial life, exist beneath the McMurdo Dry Valleys of Antarctica, according to a study published in Nature Communications. The study shows for the first time that the frozen lakes populating the Dry Valleys’ surface are connected by an expansive subterranean groundwater network.

The McMurdo Dry Valleys - the largest ice-free region in Antarctica - are a rather alien landscape, populated by glaciers, isolated lakes and frozen soils. One particularly strange feature is Blood Falls, a salty, slushy, red ooze that emerges from the boundary between Taylor Glacier and Lake Bonney. This ooze has been shown to contain a diverse microbial community and is thought to indicate the existence of a deeper brine ecosystem. However, much of the knowledge of this region is limited to the surface, with the prevailing theory suggesting that, beneath a thin layer of permafrost, much of the Dry Valleys are ice cemented earth.

To test this theory, Jill Mikucki and colleagues use an electromagnetic sensor mounted on a helicopter to map the temperature and moisture content of materials beneath the McMurdo Dry Valleys’ surface. The authors show that the Dry Valleys are not ice cemented, but instead host a subterranean network of salty liquid at temperatures well below freezing and within the range suitable for microbial life.

While the authors’ findings indicate that this deep briny groundwater system provides a conduit between the Dry Valleys’ lakes and a likely source for the crimson ooze pouring from the snout of Taylor Glacier, additional evidence is required to determine whether a deep brine ecosystem exists.

doi: 10.1038/ncomms7831

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