Earlier winter/spring runoff and snowmelt during warmer winters lead to lower summer chlorophyll‐ a in north temperate lakes
Earlier winter/spring runoff and snowmelt during warmer winters lead to lower summer chlorophyll‐ a in north temperate lakes
复制标题
冬季/春季径流提前和暖冬期间的融雪导致北温带湖泊夏季叶绿素含量降低
DOI：
10.1111/gcb.15797
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发表时间：
2021
影响因子：
11.6
通讯作者：
Hetherington, Amy Lee
中科院分区：
文献类型：
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作者：
Hrycik, Allison R.;Isles, Peter D.;Adrian, Rita;Albright, Matthew;Bacon, Linda C.;Berger, Stella A.;Bhattacharya, Ruchi;Grossart, Hans‐Peter;Hejzlar, Josef;Hetherington, Amy Lee
冬季条件，如冰盖和积雪，在北方纬度迅速变化，可能对湖泊过程产生重要影响。例如，流域的融雪-湖泊水文学的一个定义性特征，因为它提供了很大一部分的年度养分输入-正在变得更早。因此，较早和较短的融雪期预计会影响每年的浮游植物生物量。为了检验这一假设，我们开发了一个指标的径流时间的基础上，1月1日至5月31日之间发生的50%的累积径流的日期。径流指数的计算使用流入，流出，或从附近的河流在欧洲和北美的41个湖泊流量流量。然后将径流指数与每个湖泊5-53年的夏季叶绿素a（Chl‐a）浓度（浮游植物生物量的代理）进行比较。较早的径流通常对应于较低的夏季叶绿素a。此外，径流较早的年份也有较低的冬/春季径流量，更长的径流，和更早的结冰。我们研究了几个湖泊特征，这些特征可能会调节径流时间和夏季叶绿素浓度之间关系的强度;然而，我们测试的协变量对这种关系几乎没有影响。冰出日期与夏季叶绿素浓度无明显相关性。我们的研究结果表明，冬季条件的持续变化可能对夏季浮游植物生物量和生产产生重要影响。
Winter conditions, such as ice cover and snow accumulation, are changing rapidly at northern latitudes and can have important implications for lake processes. For example, snowmelt in the watershed—a defining feature of lake hydrology because it delivers a large portion of annual nutrient inputs—is becoming earlier. Consequently, earlier and a shorter duration of snowmelt are expected to affect annual phytoplankton biomass. To test this hypothesis, we developed an index of runoff timing based on the date when 50% of cumulative runoff between January 1 and May 31 had occurred. The runoff index was computed using stream discharge for inflows, outflows, or for flows from nearby streams for 41 lakes in Europe and North America. The runoff index was then compared with summer chlorophyll‐a(Chl‐a) concentration (a proxy for phytoplankton biomass) across 5–53 years for each lake. Earlier runoff generally corresponded to lower summer Chl‐a. Furthermore, years with earlier runoff also had lower winter/spring runoff magnitude, more protracted runoff, and earlier ice‐out. We examined several lake characteristics that may regulate the strength of the relationship between runoff timing and summer Chl‐aconcentrations; however, our tested covariates had little effect on the relationship. Date of ice‐out was not clearly related to summer Chl‐aconcentrations. Our results indicate that ongoing changes in winter conditions may have important consequences for summer phytoplankton biomass and production.