ピンク色の氷河、正体は藻　伊アルプスで調査進む

【ガヴィア峠ＡＦＰ＝時事】イタリアの科学者らが、アルプスのプレゼナ氷河で見られる謎めいたピンク色の氷河について、調査を進めている。色は藻によるもので、気候変動を加速させるという。（写真はプレゼナ氷河で見られるピンク色の雪）
　藻の出どころについては議論があるが、イタリア学術会議のビアージョ・ディマウロ氏は、グリーンランドで見られるのと同種のものである可能性が高いと語る。同氏はスイスのモルテラッチ氷河で藻類の研究をしていた。
　アンチロニーマ・ノルデンスキオエルディーとして知られる藻は、グリーンランドのいわゆる暗色域に生育する。暗色域でも氷の融解が進んでいる。
　ディマウロ氏は「藻は危険ではない。中緯度の春夏に見られる自然現象だが、極地でも発生する」と説明する。
　通常、氷は太陽光の８０％以上を大気中に反射する。しかし藻が現れることで氷の色が暗くなり、熱を吸収して氷の融解が加速する。
　氷の融解が進むと藻の生育に不可欠な水と空気が供給され、さらに藻が繁殖し、氷をピンク色に染める。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2020/07/07-13:11）

Scientists in Italy are investigating the mysterious appearance of pink glacial ice in the Alps, caused by algae that accelerate the effects of climate change.
There is debate about where the algae come from, but Biagio Di Mauro of Italy's National Research Council said the pink snow observed on parts of the Presena glacier is likely caused by the same plant found in Greenland.
The alga is not dangerous, it is a natural phenomenon that occurs during the spring and summer periods in the middle latitudes but also at the Poles, said Di Mauro, who had previously studied the algae at the Morteratsch glacier in Switzerland.
The plant, known as Ancylonema nordenskioeldii, is present in Greenland's so-called Dark Zone, where the ice is also melting.
Normally ice reflects more than 80 percent of the sun's radiation back into the atmosphere, but as algae appear, they darken the ice so that it absorbs the heat and melts more quickly.
More algae appear as the ice melts more rapidly, giving them vital water and air and adding red hues to the white ice at the Passo Gavia, altitude 2,618 metres (8,590 feet).
Everything that darkens the snow causes it to melt because it accelerates the absorption of radiation, said Di Mauro.
We are trying to quantify the effect of other phenomena besides the human one on the overheating of the Earth, said Di Mauro, noting that the presence of hikers and ski lifts could also have an impact on the algae.
Tourists at the glacier lament the impact of climate change.
Overheating of the planet is a problem, the last thing we needed was algae, said tourist Marta Durante.
Unfortunately we are doing irreversible damage. We are already at the point of no return, I think.
Elisa Pongini from Florence said she felt the Earth was giving us back everything we have done to it.
2020 is a special year: terrible things have happened, she said. In my opinion, atmospheric phenomena are worsening. Climate change is increasingly evident.