Long-term dynamics of biota in the Bering Sea macroecosystems and its determinant factors. Communication 1. Retrospective analysis and review of conceptions for patters in dynamics of the Bering Sea populations and communities
Conceptions for patterns and reasons of dynamics in biota of the Bering Sea macroecosystems in the last decades of 20th century and beginning of 21st century are reviewed and critically analyzed. In retrospective analysis, transformations of pelagic and benthic communities are explained within two principally different conceptions: i) onward global warming, and ii) cyclic decadal-scale fluctuations of the climate and oceanographic regime. Both conceptions agree with a strong dependence of marine populations, biocenoses and ecosystems dynamics on decadal changes in climate and oceanographic regime. Contrasting with the former conception, prevailing recently, the second one is supported on contemporary warming as the result of natural 5-decadal cyclicity, without significant impact of the greenhouse effect. This warming tendency supposedly would be changed to cooling phase in the beginning of the second decade of 21 century. There is not conclusive to regard all recent dramatic events in the Bering Sea ecosystems to an onward global warming which will continue to the middle or end of 21st century. However, since biological phenomena are complex and caused by many factors, they do not reoccur exactly in the same phases of cyclic fluctuations, even in similar environmental conditions. These cause-effect mechanisms of populations and communities dynamics are still poorly understood. Among the possible mechanisms, the hypothesis of cascading shifts in ecosystems is considered critically on the example of consequences of whales overharvesting in 1950-1960s. There is concluded that traditional research methods are not sufficient to elucidate the mechanisms of marine populations' fluctuation, with their high abundance from time to time. A new conception operating with quanta of cosmic and biospheric energy is proposed.