Abstract—

For the first time, the species composition of heterotrophic nanoflagellates, their quantitative characteristics, and abundance and biomass of their main food objects—bacteria and picophytoplankton, were determined in the water column and sediments of the Laptev Sea. In early autumn, an increase in the number and biomass of planktonic flagellates was recorded on a meridional transect from the Lena River delta to the deep-sea zone in the area of the internal shelf impacted by freshwater input from the Lena River. The pattern of the vertical distribution of planktonic flagellates differed in different parts of the sea, but everywhere their largest number was confined to either the surface or near-bottom layers. The quantitative parameters of planktonic flagellates correlated positively with the temperature, bacterial abundance, and biomass, and negatively correlated with water salinity. The abundance and biomass of heterotrophic flagellates in surface sediments was three to four orders of magnitude higher than in the water column and exceeded those of planktonic flagellates at shallow sites under 1 m². A total of 28 species and forms of heterotrophic flagellates have been identified. Representatives of two taxonomic groups—Kinetoplastea and Stramenopiles, the most tolerant to the salinity—dominated in the community. The species richness of the flagellates decreased with water depth, it was minimum in less saline coastal waters, and it increased in the deep-sea area.

中文翻译：

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拉普捷夫海中上层带和沉积物中的异养纳米鞭毛

摘要—

在拉普捷夫海的水柱和沉积物中，首次确定了异养纳米鞭毛的物种组成，数量特征以及主要食物（细菌和浮游浮游生物）的丰度和生物量。在秋初，受莉娜河输入的淡水影响，从里娜河三角洲到内陆架深海区的子午断面上的浮游鞭毛虫数量和生物量都有所增加。浮游鞭毛虫的垂直分布模式在海洋的不同部分有所不同，但是到处都有最大数量的局限在表层或近底层。浮游鞭毛虫的定量参数与温度，细菌丰度和生物量呈正相关，与水盐度呈负相关。表层沉积物中异养鞭毛虫的丰度和生物量比水柱高3到4个数量级，并且在1 m以下的浅层场所超过了浮游鞭毛虫的丰度和生物量。²。总共鉴定了28种异养鞭毛虫。两种生物分类群的代表-原生质体和对盐碱度最耐受的Stramenopiles-在社区中占主导地位。鞭毛的物种丰富度随水深而降低，在盐碱度较低的沿海水域中最低，而在深海地区则增加。