Environmental impact of removal of a large-scale sluice gate on Nakaumi Lagoon and adjacent coastal waters, southwest Japan: Evidence from long-term foraminiferal monitoring
Environmental impact of removal of a large-scale sluice gate on Nakaumi Lagoon and adjacent coastal waters, southwest Japan: Evidence from long-term foraminiferal monitoring
复制标题
拆除大型水闸对日本西南部中海泻湖及邻近沿海水域的环境影响：长期有孔虫监测的证据
DOI：
10.1016/j.marenvres.2022.105767
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发表时间：
2022
影响因子：
3.3
通讯作者：
Takata Hiroyuki
中科院分区：
文献类型：
--
作者：
Nomura Ritsuo;Tsujimoto Akira;Takata Hiroyuki
一座大型水闸于2005年至2009年间被拆除，该水闸于1974年在日本西南部修建，是一项回收和淡化泻湖水的国家项目。为了考察这种清除对Nakaumi泻湖和附近沿海水域的影响，我们分析了沿海沉积物岩芯的有孔虫组合和在泻湖监测的10年(2001-2010年)期间获得的样本。沉积物岩芯的~(210)Pb(EX)测年表明，近岸水域的沉积物积累速率增加，这意味着拆除闸门有利于包括有机物在内的细粒物质的排放。观察到的凝集性有孔虫的增加和钙质物种的减少与泥沙堆积速率有关，这些变化发生在2005年水闸开始拆除的时候。在Nakaumi泻湖，自2005年以来，在6米长的水柱中零星地出现了沿海物种--半球藻，而适应于泻湖的Ammonia“beccarii”也在减少。闸门的拆除，加上海平面的上升，允许更多的海水流入，并稳定了Nakaumi泻湖每月的深水盐度波动。
A large-scale sluice gate, which was built in southwest Japan as a national project to reclaim and desalinate lagoon water in 1974, was removed between 2005 and 2009. To examine the impact of this removal on both Nakaumi Lagoon and the nearby coastal waters, we analyzed the foraminiferal assemblages of a coastal sediment core and of samples obtained during 10 years of lagoon monitoring (2001–2010). Detailed210Pb(ex)dating of the sediment core revealed an increased sediment accumulation rate in the coastal waters, implying that discharge of fine-grained materials, including organic matter, was facilitated by removal of the sluice gate. The observed increase in agglutinated foraminifera and decrease in calcareous species was related to the sediment accumulation rate, and these changes occurred close to 2005, when sluice-gate removal began. In Nakaumi Lagoon, the sporadic presence of the coastal speciesQuinqueloculina seminulawithin the 6-m water column and the decline in the lagoon-adaptedAmmonia “beccarii”have occurred since 2005. The removal of the sluice gate, plus the sea-level rise, allowed greater seawater inflow and stabilized the monthly deep-water salinity fluctuations in Nakaumi Lagoon.