A Relict Lagoon in the Porya Bay (White Sea, Kandalaksha Bay): What Has Changed over the Past 90 Years?
In the 1930s, a scientific group from the White Sea Methodological Station of the State Hydrological Institute studied in detail a relict reservoir in the eastern part of the Porya Bay under the local name “Ozerki.” It consists of three reaches, one is connected to the sea at high tide, the next is...
Main Authors: | , , , , , , , , , , , , , , , , , |
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Other Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | Russian |
Published: |
Izvestiya Rossiiskoi Akademii Nauk. Seriya Geograficheskaya
2023
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Subjects: | |
Online Access: | https://izvestia.igras.ru/jour/article/view/1671 https://doi.org/10.31857/S2587556622060061 |
Summary: | In the 1930s, a scientific group from the White Sea Methodological Station of the State Hydrological Institute studied in detail a relict reservoir in the eastern part of the Porya Bay under the local name “Ozerki.” It consists of three reaches, one is connected to the sea at high tide, the next is connected with the first through a narrow shallow strait, and the last, apex reach communicates with the middle one. A re-examination almost 90 years later showed that due to the ongoing post-glacial uplift of the coast, the thresholds separating the “Ozerki” from the sea became shallower. With the help of pressure loggers, it has been established that the tide in the lagoon now begins at a sea level 20–30 cm higher than in the 1930s. As a result of progressive isolation, a stable vertical stratification has developed in the apex reach indicating possible meromoxis, and an anoxic zone with a high hydrogen sulfide concentration has appeared, which occupies a third of the depth of the reservoir; the concentration of mineral phosphorus increased by two orders of magnitude. In the reaches, an increase in the total abundance of zooplankton is traced with distance from the sea, an additional ecological niche appears—a chemocline, in which marine rotifers dominate in the early stages of isolation, and polychaete larvae from the order Spionidae dominate after the formation of a permanent hydrogen sulfide zone. При регрессии моря прибрежные морские участки могут оказываться в изоляции от моря, в результате чего их водная экосистема полностью трансформируется. Изучение последствий естественной изоляции важно для прогнозирования состояния водоемов в будущем, а также при проектировании искусственных сооружений, отчленяющих части морских акваторий. В 1930-х годах научной группой с Беломорской методической станции Государственного гидрологического института (ГГИ) был подробно изучен реликтовый водоем в восточной части Порьей губы под местным названием “Озерки”. Это лагуна, состоящая из трех ковшей, один из которых сообщается с ... |
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