Isotopic evidence of increasing water abundance and lake hydrological change in Old Crow Flats, Yukon, Canada
Isotopic evidence of increasing water abundance and lake hydrological change in Old Crow Flats, Yukon, Canada
复制标题
DOI：
10.1088/1748-9326/ac3533
复制
发表时间：
2021-12-01
影响因子：
6.7
通讯作者：
Wolfe, Brent B.
中科院分区：
文献类型：
--
作者：
MacDonald, Lauren A.;Turner, Kevin W.;Wolfe, Brent B.
富含湖泊的北部永久冻土地貌对变化的气候条件很敏感，但由于这些偏远地区缺乏长期、可持续的监测计划，跟踪实时和潜在的多种水文响应(例如湖泊扩张、水位下降、排水)的能力是具有挑战性的。育空的老乌鸦平原(OCF)是具有国际重要性的拉姆萨尔湿地，由于担心低水位及其对野生动物栖息地和传统生活方式的影响，在国际极地年(2007-2008)期间进行了多学科研究，并导致建立了水生生态系统监测计划。在这里，我们报告了OCF的14个典型热岩溶湖泊的水同位素数据，以及13年(2007-2019年)期间(2007-2019年)的时间序列，其中包括输入水的同位素组成和蒸发-流入比。尽管根据最初的调查，湖泊跨越多种水文类别(即降雨为主、融雪为主和蒸发为主)，但应用广义相加模型和气象记录得出的明确趋势表明，湖泊越来越多地受到降雨的影响，而且可能受到永久冻土融化的水的影响。这些投入来源导致了更积极的湖泊水量平衡。鉴于降雨在OCF和其他地方引起热岩溶湖泊排水事件中的记录作用，我们预计OCF的横向水输出的脆弱性增加。这项研究证明了基于同位素的长期监测方案在确定富含湖泊的永久冻土景观中气候变化的水文后果方面的价值。
Lake-rich northern permafrost landscapes are sensitive to changing climate conditions, but ability to track real-time and potentially multiple hydrological responses (e.g. lake expansion, drawdown, drainage) is challenging due to absence of long-term, sustainable monitoring programs in these remote locations. Old Crow Flats (OCF), Yukon, is a Ramsar Wetland of International Importance where concerns about low water levels and their consequences for wildlife habitat and traditional ways of life prompted multidisciplinary studies during the International Polar Year (2007-2008) and led to the establishment of an aquatic ecosystem monitoring program. Here, we report water isotope data from 14 representative thermokarst lakes in OCF, the foundation of the monitoring program, and time-series of derived metrics including the isotope composition of input waters and evaporation-to-inflow ratios for a 13 year period (2007-2019). Although the lakes spanned multiple hydrological categories (i.e. rainfall-, snowmelt- and evaporation-dominated) based on initial surveys, well-defined trends from application of generalized additive models and meteorological records reveal that lakes have become increasingly influenced by rainfall, and potentially waters from thawing permafrost. These sources of input have led to more positive lake water balances. Given the documented role of rainfall in causing thermokarst lake drainage events in OCF and elsewhere, we anticipate increased vulnerability of lateral water export from OCF. This study demonstrates the value of long-term isotope-based monitoring programs for identifying hydrological consequences of climate change in lake-rich permafrost landscapes.