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首页> 外文期刊>Lakes & Reservoirs >Long-term changes in the aquatic biota of Lake Abashiri, a meromictic lake in northeastern Hokkaido, Japan
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Long-term changes in the aquatic biota of Lake Abashiri, a meromictic lake in northeastern Hokkaido, Japan

机译：日本北海道东北部的淡水湖网走湖的水生生物的长期变化

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Lake Abashiri is an example of a meromictic lake under the stability of upper oligohaline water and lower polyhaline water, but a brackish lake on the whole. Nevertheless, boundary depth of the hypolimnetic layer has gradually decreased with time. At the same time, this has led to an increase in salinity and eutrophication in the epilimnion and to an acceleration of deoxygenation of the hypolimnion, attributed to the upwelling of bluish water. In order to investigate succession of the aquatic biota linked to these hydrological changes, results of occasional long-term studies on the distribution of plankton and benthos were summarized, mostly from Japanese publications of lake surveys. In each result, the boundary of the polyhaline hypolimnetic layer has gradually risen from 13 to 7 m depth between 1932 and 1955, and has been determined, in recent years, to be 5.5 m. Salinity of the epilimnion was lower than 0.1‰ in 1930s, and 0.5–0.6‰ in the 1940s before 1949. Thereafter, salinity increased to 1.8–2.3‰ until recently, with levels now often over 3‰. Following these hydrological changes, the succession of planktonic fauna and flora, particularly of the dominant species, has exhibited a gradual change from freshwater to brackish or salinity tolerant species during the 72 year period from 1926 to 1997, including a period of variable species composition in 1975–1980 and a period of degradation after that. In contrast, according to available data, the benthic community has remained unchanged in terms of the composition of dominant species in all habitats during the same 72 year period. The dominance of some plankton and benthos species has been maintained over several decades, although the community structures have displayed a few phases of abundance and regression during these 72 years.
机译：网走湖是上高盐度水和下多盐度水的稳定状态下的淡红湖的一个例子，但总体上是咸淡的湖。然而，低磁层的边界深度随着时间逐渐减小。同时，这导致由于上蓝水的上升，上生石灰中的盐度和富营养化增加，并使下生石灰的脱氧加速。为了调查与这些水文变化有关的水生生物的演替，对浮游生物和底栖生物的分布进行了不定期的长期研究的结果总结了下来，大部分来自日本的湖泊调查出版物。在每个结果中，多盐水低铁层的边界在1932年至1955年之间已从13 m的深度逐渐增加，并且近年来已确定为5.5 m。上世纪的盐度在1930年代低于0.1‰，在1949年之前的1940年代低于0.5-0.6‰。此后，直到最近，盐度一直提高到1.8-2.3‰，现在经常超过3‰。在经历了这些水文变化之后，从1926年至1997年的72年间，一系列浮游动植物，特别是优势物种的浮游动物已呈现出从淡水到耐咸或耐盐的物种的逐渐变化。 1975-1980年，此后经历了一段退化。相反，根据现有数据，在相同的72年期间，底栖动物群落在所有生境中的优势物种组成方面均保持不变。尽管在这72年中，群落结构已显示出一些丰度和退化阶段，但某些浮游生物和底栖生物仍保持着主导地位。

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