Abstract

The research is based on the materials collected during cruise 66 of R/V Akademik Mstislav Keldysh in the Yenisei estuary and over the adjacent Kara Sea shelf in the latitudinal range from 71°50.5′ to 75°55.0′ N. The studies were performed from July 25 to 27, 2016, three weeks after the end of the flood period. Two hundred fifty species of plankton algae were recorded. Well-pronounced latitudinal zoning in phytoplankton communities structure associated with changes in the hydrophysical and hydochemical conditions of the pelagic environmental was determined. The maximum species diversity was formed by diatoms, green and blue-green algae in the southern desalinated part of the estuary (<1 PSU) and by diatoms and dinoflagellates in the offshore areas. The highest algae abundance and biomass, 2.7–2.9 × 10⁶ cell/L and 1.1–1.5 g/m³, respectively, were recorded in the inner desalinated part of the estuary, where freshwater diatoms of the genus Aulacoseira dominated. The distribution of freshwater algae northwards was bounded by the 12–15 PSU surface isohaline (74°20′ N). The most pronounced decline in phytoplankton abundance and biomass was found in the outer part of the estuary north of ~73° N. In the middle shelf to the north of the Yenisei estuary, the maximum abundance (up to 740 × 10³ cell/L) and biomass (up to 240 mg/m³) of phytoplankton were recorded at the depths of 30–40 m with low illumination and high nutrient concentration, which was also typical of the Ob region in spring–summer.

中文翻译：

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晚春叶尼塞河口和邻近的卡拉海架植物群落的结构

摘要

该研究基于叶尼塞河口的R / V Akademik Mstislav Keldysh 66号巡洋舰在北纬71°50.5'至75°55.0'范围内相邻卡拉海陆架上的航行中收集的材料。 2016年7月25日至27日，即洪水期结束后的三周。记录了250种浮游生物藻类。确定了浮游植物群落结构中与远洋环境的水物理和水化学条件变化相关的明显的纬度分区。最大的物种多样性是由河口南部淡化部分（<1 PSU）的硅藻，绿藻和蓝藻以及近海地区的硅藻和鞭毛藻形成的。最高的藻类丰度和生物量，2.7–2.9×10在河口的内部淡化部分记录到分别为⁶细胞/ L和1.1–1.5 g / m ³，其中Aulacoseira属的淡水硅藻占主导地位。淡水藻类向北的分布以12-15 PSU表面等盐度（74°20'N）为边界。在〜73°N以北的河口外部发现了最明显的浮游植物丰度和生物量下降。在叶尼塞河口以北的中层架子，最大丰度（高达740×10 ^3个细胞/升）在低照度和高养分浓度的30–40 m深度记录了浮游植物的）和生物量（高达240 mg / m ³），这也是春夏季Ob地区的典型特征。