Abstract

Communities of macrozoobenthos in the White Sea coastal water bodies that have partially or completely lost connection with the sea as a result of postglacial land uplift, are studied. As the degree of isolation from the sea increases, stable vertical stratification with a tendency to meromixis and gradual dilution of seawater provide the conditions for the formation of an unusual composition of macrofauna and succession, from a normal or slightly depleted marine biome to a completely freshwater ecosystem. Data collected in the years 2012–2017 present the macrozoobenthos community of five marine lagoons and four meromictic lakes in comparison with the marine communities of Kislaya Inlet, which connects the two water bodies studied, and with the freshwater lakes of the Kindo Peninsula. The typology of the water bodies was carried out according to the degree of isolation, taking into account the hydrological regime and differences in fauna lists. A naturally determined change in bottom communities occurs as the degree of isolation of the water body from the sea increases. In marine lagoons, regularly flooded by tides, there is a community of Macoma balthica (L. 1758)–Pontonema vulgare (Bastian 1865) Filipjev 1916, widespread in the marine littoral. In more isolated lagoon-type water bodies with a similar set of species, Mytilus edulis L. 1758 and Mya arenaria L. 1758 make up a significant share in biomass in addition to M. balthica. The populations of the gastropod mollusk Hydrobia ulvae (Pennant 1777) are much developed here. Even at this stage, the fauna comprises more littoral eurybionts (H. ulvae, M. balthica, M. arenaria, M. edulis, Arenicola marina (L. 1758), Tubificoides benedeni (d’Udekem 1855), chironomids, etc.) and less sublittoral stenohaline forms. At the next stage, H. ulvae dominates by biomass, and the share of the chironomid Chironomus gr. salinarius and oligochaete T. benedeni increases as well. Insects and their larvae (beetles, chironomids, and other dipterans) settle in shallow areas. In meromictic lakes, where a salt aerobic layer is preserved under the pycnocline, the fauna of the mixolimnion mainly comprises insect larvae, while only a few euryhaline forms remain from the marine fauna, namely, the amphipod Gammarus duebeni Lilljeborg 1852 and the chironomid Ch. gr. salinarius. At the stage of complete isolation from the sea, conditions are anaerobic below the pycnocline and, despite the suitable salinity, there is no marine fauna. In such water bodies, the benthos is represented exclusively by freshwater forms, mainly insects and mollusks. In completely freshwater bodies, chironomids make up the majority of the biomass; each lake has its own set of species, which changes from year to year. In the fresh water of Nizhnee Ershovskoe Lake, the population of G. duebeni remains in the part of the lake closest to the sea. The species diversity decreases as the water body is isolated from the sea; the maximum number of species was found in marine lagoons near Sonostrov Island (23–34 species); in Kislo-Sladkoe Lake, 10–15 species are found per survey. In Bol’shie Khruslomeny Lake, the aerobic part of the monimolimnion has a critical salinity and the species diversity is minimal (6–10 species). The number of species increases again after a stable fresh layer appears in the water body. The quantitative characteristics of the macrobenthos change in a similar way. The maximum abundance were noted in marine lagoons; in Kislo-Sladkoe Lake, the average abundance is significantly lower. In the meromictic water bodies with a fresh mixolimnion, the maxima of abundance and biomass are observed in the upper 0.5-m water layer, while in marine lagoons the maxima are located in the depth range of 1.0–2.5 m; in addition, in less isolated water bodies, the maximum biodiversity is observed in deeper layers than in more isolated ones. This layer is characterized by the highest content of dissolved oxygen, and often by supersaturation. The benthos abundance varies greatly in freshwater bodies.

中文翻译：

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莫斯科国立大学，白海坎达拉克夏湾，白海生物站附近白海隔离阶段不同阶段的沿海水体底栖动物群落

摘要

研究了白海沿岸水体中的大型动物群，这些区域由于冰川后的陆地隆升而与海洋部分或完全失去了联系。随着与海洋的隔离程度的增加，从垂直或分层的趋势到混合混杂的趋势，海水逐渐稀释，为从正常的或略微枯竭的海洋生物群落到完全淡水的大型动物群和演替的形成提供了条件。生态系统。与连接两个研究水体的Kislaya Inlet的海洋群落以及Kindo半岛的淡水湖泊相比，2012-2017年收集的数据显示了五个海洋泻湖和四个meromictic湖的大型动物群落。水体的分类根据隔离程度进行，并考虑了水文状况和动物群清单的差异。当水体与海洋的隔离度增加时，底部群落的自然变化就会发生。在经常被潮水淹没的海洋泻湖中，有一个Macoma balthica（L. 1758）– Pontonema vulgare（Bastian 1865）Filipjev 1916，广泛分布于海洋沿岸。在用一组类似的物种，更孤立泻湖型水体贻贝L. 1758和妙蒿属1758弥补除了生物量显著份额M. balthica。腹足纲软体动物水bia（Pennant 1777）的种群在这里得到很大发展。即使在这个阶段，该动物区系也包含更多的沿海真核生物（H. ulvae，M。balthica，M。arenaria，M。edulis，Arenicola marina（L. 1758），Tubificoides benedeni（d'Udekem 1855），chironomids等）。和较少的近滨性盐卤形式。在下一阶段，ul。ulvae以生物量和chironomid Chironomus gr的份额为主。salinarius和oligochaete T. benedeni也增加。昆虫及其幼虫（甲虫，尺虫和其他双壳类动物）定居在浅水区。在茂盛的湖泊中，在比浓可可林下保留了盐的需氧层，混合类动物的动物群主要包括昆虫幼虫，而海洋动物群中仅存有少量的卵形，即两栖类的Gammarus Duebeni Lilljeborg 1852和Chironomid Ch。gr 。盐沼。在与海完全隔离的阶段，比多菌灵以下的条件是厌氧的，尽管盐度合适，但没有海洋动物。在这种水体中，底栖动物仅以淡水形式（主要是昆虫和软体动物）为代表。在完全淡水的水体中，鸟足类动物占生物量的大部分。每个湖泊都有其自己的种类，每年都会变化。在Nizhnee Ershovskoe湖，人口的淡水G. duebeni仍然保留在最靠近大海的湖中。随着水体与海洋隔离，物种多样性降低；在Sonostrov岛附近的海洋泻湖中发现的物种数量最多（23–34种）；根据调查，在Kislo-Sladkoe湖中发现了10–15种。在Bol'shie Khruslomeny湖中，单imolimnion的好氧部分具有临界盐度，物种多样性极低（6-10种）。在水体中出现稳定的新鲜层后，物种数再次增加。大底栖动物的数量特征以类似的方式变化。在海洋泻湖中注意到最大的丰度。在Kislo-Sladkoe湖，平均丰度明显降低。在具有新鲜混合岩浆的铁质水体中，在上部0.5米水层中观察到了丰度和生物量的最大值，在海洋泻湖中，最大值位于1.0–2.5 m的深度范围内；此外，在较少的孤立水体中，与较孤立的水体相比，深层的生物多样性最大。该层的特征在于溶解氧的含量最高，并且通常以过饱和为特征。在淡水体中，底栖动物的丰度变化很大。