We studied distribution and growth of Serripes groenlandicus and Macoma calcarea in the southeastern part of the Pechora Sea. The hypothesis was tested that trends in the site-to-site variability of population characteristics of these two bivalve species were driven by their feeding types (suspension-feeder and deposit-feeder, respectively). However, such a trend was found only in the abundance distribution of these species and site-to-site variability in growth rates of S. groenlandicus. M. calcarea density on silty sediments was almost twice as high as on sandy sediments, while Serripes biomass was almost 1.5 times higher on sandy sediments than on silty sediments. The slowest-growing Serripes were found at the deepest stations and in habitats with the largest content of fine fractions (silt) in sediments. Differences in the growth of S. groenlandicus could reflect variability of feeding conditions of this suspension-feeder (e.g., hydrodynamic conditions). Thus, the growth rate of S. groenlandicus was sensitive to environmental conditions, which means it can be used as an indicator of their changes. In general, S. groenlandicus in the Pechora Sea is very slow-growing compared to other areas (maximum life span and shell length are 28 years and 70 mm, respectively). Their growth rate was closest to that in Arctic-influenced locations. On the contrary, the maximum life span and shell length of M. calcarea in the Pechora Sea (15 years and 30 mm, respectively) were similar to those in other parts of the distribution area. No significant differences were found in the group growth of M. calcarea from different studied localities.
The structure dynamics of Mya arenaria beds in the Kandalaksha Bay of the White Sea was observed for 7-35 years. We aimed to identify the patterns of the spatial-temporal organization of the clam beds by studying recruitment, growth, and mortality. Gaps between successful bed recruitment could exceed 10 years. The results of our investigations mostly support the hypothesis that the fluctuations in the recruitment level were determined both by the intensity of intraspecific relations and by the spat survival during the first year of life. Group growth rate and average annual mortality rate of soft-shell clams were sensitive to environmental conditions, which means they can be used as an indicator of their changes. M. arenaria in the most silted biotopes was characterized by the slowest growth and the highest mortality. However, the internal heterogeneity of the beds in terms of the ecological properties of individuals was high. The variation of the individual growth rate within the beds was comparable with that of the group growth rate between the studied locations. M. arenaria mortality rate varied with age. It is assumed the clam survival depends mostly on the degree of protection, intraspecific relationships, and aging.
Аннотация. Предмет. Оценка уровня экологической опасности автотранспорта на участке урбанизированной территории. Цели. Теоретическое и практическое обоснование использования комплексного подхода к оценке параметров системы «Автотранспортный поток-урбанизированная территория». Методология. Моделирование процесса функционирования автотранспортных потоков в условиях урбанизированной территории за счёт более полного учёта отрицательного экологического эффекта совокупно действующих загрязнений химического и энергетического характера. Результаты. Сравнительный анализ организации движения автотранспорта в условиях урбанизированной территории по экологическим критериям с использованием классического и комплексного подходов. Выводы. Выявленные противоречия позволили доказать адекватность предлагаемых положений, касающихся разработки и применения нового критерия-комплексного индекса экологической нагрузки, который дополняет модельные представления о системе «Автотранспортный поток-урбанизированная территория».
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