ICYCLE: In situ ice-water ChemistrY investigation of Carbon and Life in Extreme environments.

Experiment description: Life on Earth can often be found at the boundary
between two physical layers, as energy exchange often occurs at these
boundaries. One of the least studied interface is the ice-water boundary.
On Earth, the dynamic freezing environment of the ice-water interface leads
to an exchange of gases, ions, and other compounds that modulate the
habitability of both lake and marine environments. We proposed a study to
investigate the ice-water interface in a methane-enriched lake on the North
Slope of Alaska (Sukok lake). We plan to map and study the sources,
abundance, and transformation of methane up from lake sediments, into the
water column, into the ice, and ultimately its release to the atmosphere.
We plan to use a DTS system to measure the freeze-down of the lake with the
onset of Arctic winter. This will allow direct calibration of data
collected by the under-ice rover so that we can model the timing and
process of freeze down at high resolution. We’ll use a 1km cable wrapped
around a non-compressible composite pipe to deploy in the shallow, 2m lake.
The data collected at 1-2 mm-level resolution will be used to follow the
freezing front of the lake, in addition to recording ice vs. underlying
water temperatures throughout the winter. In addition the timing of spring
melt processes will also be recorded. This data will be combined with the
buoyant rover-collected data to derive freezing rate. The larger project is
studying the incorporation of solutes and microorganisms into the freezing
front, and the ice as a habitat.

实验说明：地球上的生命常栖息于两种物理界面之间，因为能量交换往往发生在这类界面处。研究程度最低的界面之一便是冰水界面。在地球环境中，冰水界面的动态冻结环境会引发气体、离子及其他化合物的交换过程，进而调控湖泊与海洋环境的宜居性。我们提出一项研究，旨在探究阿拉斯加北坡一处富甲烷湖泊——苏科克湖（Sukok Lake）的冰水界面。我们计划绘制并研究甲烷的来源、丰度与转化过程：甲烷从湖泊沉积物向上迁移，进入水体层，再进入冰层，最终释放至大气中。我们计划采用DTS系统，在北极冬季来临之际监测湖泊的冻结过程。这将实现对冰下漫游车采集数据的直接校准，以便我们以高分辨率构建冻结过程的时间与机制模型。我们将使用缠绕于不可压缩复合管道上的1千米线缆，在这片2米深的浅湖中进行部署。该系统将以1-2毫米的分辨率采集数据，用于追踪湖泊的冻结锋面，并全程记录冬季冰层与下层水体的温度差异。此外，春季融冰过程的时间节点也将被同步记录。该数据集将与漂浮式漫游车采集的数据相结合，以计算冻结速率。本大型研究项目还将探究溶质与微生物在冻结锋面的嵌入过程，以及冰层作为栖息地的相关特性。