排序方式: 共有6条查询结果,搜索用时 15 毫秒
1
1.
This paper investigates the dependence of phytoplankton production upon rhythm and rate of zooplankton grazing and presents a mathematical model for calculating the most important parameters. Both uniform and non-uniform grazing are described mathematically. Non-uniform grazing, expressed by a sinusoidal curve, is usually found in bathyplanktonic ecosystems with migratory consumers. Phytoplankton production depends on the time of grazing; the nearer grazing occurs toward nightfall, the higher is the phytoplankton production. In order to calculate phytoplankton productivity and the amount of food consumed by the zooplankton, experimental data on generation time of phytoplankters, their mortality rates, initial and final standing stocks, and information on diurnal grazing rhythms must be available. If the distribution of grazing rates is sinusoidal and mortality rate constant, the equations presented allow the calculation of phytoplankton productivity with an error of about 6%. 相似文献
2.
The systematic composition of the diatom flora of the Caspian Sea is original, but poor, especially in marine species. At present, 286 species, varieties and forms, belonging to 46 genera and 4 orders are known to exist in the Caspian Sea. Of this number, 77 species and varieties (27%) are planktonic and 209 (63%) benthonic. The phytoplankton of the Caspian Sea is wholly neritic. In regard to salinity, a characteristic of the Caspian diatom flora is that it is composed of three different groups: marine, brackish, and fresh-water species. The brackish water group is of great interest, as it includes many diatoms which are known only from this water body (endemisms). The poor species-composition of the diatom flora is accounted for by variations in the hydrogical conditions of the Caspian Sea in the geological past. The formation of the flora is based on such sources as the ancient flora remains of the Upper-Tertiary Caspian-Black Sea, the younger elements of the Pliocene Sea during its isolation period, and the immigrants entering the Caspian Sea during the short period of its communication with the Black Sea. 相似文献
3.
Anna Makarova Andrey Fedoseev Eugenia Vasilyeva 《Journal of Material Cycles and Waste Management》2022,24(3):1134-1139
Journal of Material Cycles and Waste Management - The work is devoted to the study of a possible technology for the immobilization of mercury in waste, based on the principles of converting mercury... 相似文献
4.
P. S. Venediktov Yu. V. Kazimirko T. V. Krendeleva G. P. Kukarskikh V. V. Makarova S. I. Pogosyan O. V. Yakovleva A. B. Rubin 《Russian Journal of Ecology》2000,31(5):308-312
The relative yield of variable chlorophyll fluorescence in the bark of annual shoots of woody plants was measured with a portable
pulse-modulated fluorometer designed for this purpose at the Department of Biophysics (Biological Faculty, Moscow State University).
Experiments were performed to study the response of this parameter to external influences (treatment with an herbicide, water
loss, etc.). The results demonstrated the possibility of reliably recording the parameters of fluorescence in the annual shoots
of various woody plants without damaging these shoots. It is concluded that measurements of chlorophyll fluorescence in the
bark of woody plants can be used for analyzing changes in the physiological state of tree stands under the effects of natural
and anthropogenic factors. 相似文献
5.
Berezina N. A. Tiunov A. V. Tsurikov S. M. Kurbatova S. A. Korneva L. G. Makarova O. S. Bykova S. N. 《Russian Journal of Ecology》2021,52(3):247-252
Russian Journal of Ecology - Cyanobacterial blooms are regarded as a global environmental problem. The role of cyanobacteria in the food web of water bodies is still unclear. We have carried out an... 相似文献
6.
1