研究：阿拉斯加河流变色或由气候变化导致

近些年来，美国阿拉斯加州有数十条河流的河水颜色由清澈透明变成铁锈色。研究表明，这可能是气候变化令永久冻土解冻所致。相关研究报告由英国《通讯-地球与环境》杂志刊载。

卫报截图

Dozens of rivers and streams in Alaska are turning rusty orange, a likely consequence of thawing permafrost, a new study finds.

一项新的研究发现，阿拉斯加的数十条河流和溪流正在变成锈橙色，这可能是冻土融化的导致的。

The Arctic is the fastest-warming region in the globe, and as the frozen ground below the surface melts, minerals once locked away in that soil are now seeping into waterways.

北极是全球变暖最快的地区，随着地表下冻土的融化，曾经被锁住在土壤中的矿物质现在正在渗入水道。

"It’s an unforeseen impact of climate change that we’re seeing in some of the most pristine rivers in our country,” said Brett Poulin, study author and assistant professor of environmental toxicology at university of California Davis.

研究作者、加州大学戴维斯分校环境毒理学助理教授布雷特·普林说：“这是美国最原始的一些河流中看到的气候变化的不可预见影响。”

The permafrost thaw is exposing minerals to oxygen in a process known as weathering, which increases the acidity of the water and dissolves metals like zinc, copper, cadmium and iron – the most apparent metal that gives the rivers a rusty color visible even from satellite images. The study highlights the potential degradation of drinking water and risk to fisheries in the Arctic.

冻土的融化使矿物质暴露在氧气中，这个过程被称为风化，它增加了水的酸度并溶解了像锌、铜、镉和铁这样的金属——显然铁是赋予了河流即使从卫星图像中也可见的锈色的主要金属。这项研究指出了饮用水可能被污染的现状和北极渔业面临的风险。

"When mixed with another river, it can actually make the metals even more potent [in its] impact to aquatic health,” Poulin said.

普林说：“当这些河流与另一条河流汇合时，实际上会让金属对水生生物的健康产生更大的危害。”

The phenomenon was first observed in 2018, when researchers noticed the milky orange appearance of the rivers across northern Alaska’s Brooks Range, a stark contrast to the crystal clear waters seen the year prior.

这一现象最初是在2018年观察到的，当时研究人员注意到流经阿拉斯加北部布鲁克斯山脉的河流的乳橙色外观，与前一年看到的清澈水质形成了鲜明对比。

Within the year, a tributary of the Akillik river in Kobuk Valley national park saw the complete loss of two local fish species: the dolly varden and the slimy sculpin.

同年，科伯克谷国家公园内阿基利克河一条支流中的两种当地鱼类——花羔红点斑鲑和粘杜父鱼完全绝迹。

"Our data suggests that when the river turned orange, we saw a significant decrease in macroinvertebrates and biofilm on the bottom of the stream, which is essentially the base of the food web,” Poulin said of the rusting phenomenon. “It could be changing where fish are going to be able to live.”

普林在谈到锈色现象时说：“我们的数据表明，当河流变为橙色时，我们发现大型无脊椎动物和溪流底部的生物膜显著减少，而生物膜本质上是食物链的基础。这可能会让鱼类能够生存的地方发生变化。”

The rusting is a seasonal phenomenon, occurring in the summer typically during July and August, when the soil is thawed the deepest. The researchers at the National Park Service, US Geological survey and University of California Davis now want to better understand the long-term implications of the changing water chemistry in places with continuous permafrost, which includes Arctic regions such as Alaska, Canada, Russia and parts of Scandinavia.

锈蚀是一种季节性现象，发生在夏季，通常发生在7月和8月，此时土壤解冻最深。美国国家公园管理局、美国地质调查局和加州大学戴维斯分校的研究人员现在希望更好地了解永久冻土连续地区（包括阿拉斯加、加拿大、俄罗斯和斯堪的纳维亚半岛部分地区）水化学变化的长期影响。