Effects of Consecutive Extreme Weather Events on a Temperate Dystrophic Lake: A Detailed Insight into Physical, Chemical and Biological Responses
Effects of Consecutive Extreme Weather Events on a Temperate Dystrophic Lake: A Detailed Insight into Physical, Chemical and Biological Responses
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DOI：
10.3390/w12051411
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发表时间：
2020-05-01
期刊：
影响因子：
3.4
通讯作者：
McCarthy, Valerie
中科院分区：
文献类型：
--
作者：
Caldero-Pascual, Maria;de Eyto, Elvira;McCarthy, Valerie
2018年5月至7月，爱尔兰经历了一场异常的热浪，打破了长期的温度和干旱记录。这些平静、稳定的条件突然被6月下旬的第二次极端天气事件--大西洋风暴赫克托--打断。使用高频率的监测数据，再加上每两周的生物采样，我们表明，风暴直接影响的分层模式的湖Feeagh，导致强烈的混合事件。风暴过后，随着热浪的持续，湖水很快恢复了稳定。在风暴期间，施密特稳定性减少了三倍，混合层加深了9.5米，同时叶绿素a减少了两倍，但浮游动物总生物量增加了三倍。表生呼吸增加，生态系统净生产力下降。入湖河流与入湖河流的总氮：总磷的比例是解耦的，导致更高的营养水平的级联效应。氮磷失衡的阶跃变化表明浮游动物群落由磷营养约束向氮营养约束转变。湖泊的热力和生态对极端天气事件的反应的这种特征是相对罕见的，但对于我们了解湖泊如何随着全球气候变化的影响加速而变化至关重要。
Between May and July 2018, Ireland experienced an exceptional heat wave, which broke long-term temperature and drought records. These calm, stable conditions were abruptly interrupted by a second extreme weather event, Atlantic Storm Hector, in late June. Using high-frequency monitoring data, coupled with fortnightly biological sampling, we show that the storm directly affected the stratification pattern of Lough Feeagh, resulting in an intense mixing event. The lake restabilised quickly after the storm as the heatwave continued. During the storm there was a three-fold reduction in Schmidt stability, with a mixed layer deepening of 9.5 m coinciding with a two-fold reduction in chlorophyll a but a three-fold increase in total zooplankton biomass. Epilimnetic respiration increased and net ecosystem productivity decreased. The ratio of total nitrogen:total phosphorus from in-lake versus inflow rivers was decoupled, leading to a cascade effect on higher trophic levels. A step change in nitrogen:phosphorus imbalances suggested that the zooplankton community shifted from phosphorus to nitrogen nutrient constraints. Such characterisations of both lake thermal and ecological responses to extreme weather events are relatively rare but are crucial to our understanding of how lakes are changing as the impacts of global climate change accelerate.