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首页> 外文期刊>Limnology >Fluctuation of the zooplankton community in Lake Biwa during the 20th century: a paleolimnological analysis
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Fluctuation of the zooplankton community in Lake Biwa during the 20th century: a paleolimnological analysis

机译：20世纪琵琶湖浮游动物群落的波动：古湖泊学分析

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Detailed zooplankton records from a 26-cm sediment core with a time resolution of approximately 3-10 years were obtained from Lake Biwa, Japan, to examine the historical variations in the zooplankton community during the 20th century. In the sediments, selected zooplankton remains have fluctuated over the years. Daphnia - large zooplankton herbivores - did not occur from 1900 to 1920, and formed a very minor component of the zooplankton community in the following 30 years, while Bosmina - small zooplankton herbivores - were common during this period. In the mid-1960s, however, when eutrophication was noticeable in this lake, Daphnia numbers increased dramatically and became the dominant zooplankton thereafter. In contrast, Difflugia brevicolla and D. biwae, two amoeboid protozoans that live in connection with the lake bottom environment, occurred abundantly until the late 1950s. but gradually decreased after the mid-1960s. In particular, D. biwae, a species peculiar to this lake, was not found in sediment dated after 1980, suggesting its extinction. These results indicate that the zooplankton community structure changed greatly in the 1960s, and suggest that the eutrophication occurring at this time altered the relative strength of top-down and bottom-up forces on the zooplankton community in Lake Biwa. [References: 47]
机译：来自日本琵琶湖的26厘米沉积岩心的浮游动物详细记录，时间分辨率约为3-10年，用于研究20世纪浮游动物群落的历史变化。这些沉积物中，浮游动物的残留物多年来一直在波动。水蚤-大型浮游植物食草动物-在1900至1920年间没有发生，在随后的30年中仅占浮游动物群落的很小一部分，而波斯尼亚-小型浮游动物食草动物在此期间很常见。然而，在1960年代中期，当该湖出现富营养化时，水蚤数量急剧增加，并成为此后的主要浮游动物。相反，Difflugia brevicolla和D. biwae是生活在湖底环境中的两种变形虫原虫，大量繁殖到1950年代后期。但在1960年代中期以后逐渐减少。特别是在该湖特有的物种D. biwae，在1980年以后的沉积物中未发现，表明该物种已灭绝。这些结果表明，在1960年代浮游动物群落结构发生了很大变化，并表明此时发生的富营养化改变了琵琶湖浮游动物群落的自上而下和自下而上的力量的相对强度。 [参考：47]

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