Geographical and seasonal variations in mesozooplankton abundance and biomass in relation to environmental parameters in Lake Shinji-Ohashi River-Lake Nakaumi brackish-water system, Japan
Geographical and seasonal variations in mesozooplankton abundance and biomass in relation to environmental parameters in Lake Shinji-Ohashi River-Lake Nakaumi brackish-water system, Japan
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DOI：
10.1016/s0924-7963(00)00054-3
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发表时间：
2000-10-01
影响因子：
2.8
通讯作者：
Kamiya, H
中科院分区：
文献类型：
--
作者：
Uye, S;Shimazu, T;Kamiya, H
1995 - 1997年，除一个站（1年9个月）外，我们连续3年（1995-1997年）每月对日本新寺湖-大桥河-中海湖咸水系统6个站的中型浮游动物主要分类类群的丰度和生物量进行了测定。在整个区域，桡足类占绝对优势的浮游动物群落的丰度（平均值：87.9%）和生物量（83.4%）。其余的类群是枝角类（即短尾双体虫、Evadone tergestina、Penilia avirostris、Podon leuckarti和Podon palyphemoides），（Oikopleura dioica和Oikopleura longicauda），毛颚类（粗箭虫）和底栖生物的幼虫（例如多毛类、双壳类、腹足类和软甲类），浮游动物群落的地理和季节变化主要是由桡足类群落的变化来解释的。桡足类物种组成的地理差异与各物种的盐度偏好或耐受性有关。在信治湖，那里的盐度最低（平均值：4.0），Sinocalanus tenellus是单特异性丰富的零星发生的Pseudodiaptomus inopinus。在大桥河（平均盐度9.9），群落中出现了哈氏纺锤水蚤、新集纺锤水蚤、太平洋宽腹蛛和台湾长管蜂。在平均盐度为16.4 - 21.7的中海湖中部和东南部以及本庄地区，这四种鱼类比S. tenellus和P. inopinus。在盐度最高（平均24.0）的坂井海峡入口处，拟哲水蚤（Paracalanus spp.）构成了一个重要的组成部分。由于温度的季节变化较大，桡足类的丰度和生物量均表现出明显的季节性变化，在冬春季节出现巨大的年高峰。这些年度高峰可能归因于捕食者的稀缺性。(C)2000 Elsevier Science B. V.保留所有权利。
We measured the abundance and biomass of the major taxonomic groups of mesozooplankton at six stations in Lake Shinji-Ohashi River-Lake Nakaumi brackish-water system, Japan, monthly for three full years (1995-1997), except for one station (for 1 year and 9 months). Over the entire area, copepods overwhelmingly dominated the zooplankton community both in terms of abundance (mean: 87.9%) and biomass (83.4%). The remaining taxa were cladocerans (i.e. Diphanosoma brachyurum, Evadone tergestina, Penilia avirostris, Podon leuckarti and Podon palyphemoides), appendicularians (Oikopleura dioica and Oikopleura longicauda), chaetognaths (Sagitta crassa) and the larvae of benthos (e.g. polychaetes, bivalves, gastropods and malacostracans), The geographical and seasonal variations of the mesozooplankton community were therefore principally explained by the variations of the copepod community. The geographical difference in copepod species composition was associated with salinity preference or tolerance of respective species. In Lake Shinji, where the salinity was lowest (mean: 4.0), Sinocalanus tenellus was monospecifically abundant with sporadic occurrence of Pseudodiaptomus inopinus. In Ohashi River (mean salinity: 9.9), Acartia hudsonica, Acartia sinjiensis, Eurytemora pacifica and Oithona davisae added to the community. At central and southeast Lake Nakaumi and in Honjo District, where mean salinity ranged from 16.4 to 21.7, these four species became more important than S. tenellus and P. inopinus. At the entrance of Sakai Strait, where the salinity was highest (mean: 24.0), Paracalanus spp. constituted a significant component. Due to large temperature fluctuation with season, the copepods showed remarkable seasonal variations in abundance and biomass, with enormous annual peaks in winter-spring. These annual peaks might be attributed to scarce occurrence of predators. (C) 2000 Elsevier Science B.V. All rights reserved.