HR: 0800h
AN: B31A-0975    [Abstracts]
TI: An Attempt to Carry out an Ecological Indication of the Plankton Ecosystem Based on Microbiological Indices.
AU: Yakushin, V
EM: mommy@i.com.ua
AF: Institute of hydrobiology, Geroyev Stalingrada, 12, Kiev, 04212 Ukraine
AU: * Golovko, T
EM: mommy@i.com.ua
AF: Institute of hydrobiology, Geroyev Stalingrada, 12, Kiev, 04212 Ukraine
AB: Ecological indication of a water reservoir under the influence of anthropogenic factors includes structural and functional analyses of different biota components among which bacteria is one of the most important especially in ecosystem's bioenergy and control of artificial pollution. The main goal of the present study was to investigate the structure and functioning of bacterial population in ecologically different waters of Kanev reservoir to choose the most adequate parameters for evaluation of water ecosystem. The study was carried out on 10 sites of upper Kanev reservoir during summer 2004. The basic factors that influenced its hydrobiology were water flow from Kiev reservoir and discharge of industrial and household sewage from nearby cities. Such structural indices as bacteroplankton's total number and biomass, as well as the number of bacteria that metabolize easy degradable organic compounds did not show clear spatial conformity to natural laws. However, the evaluation of functional status of plankton bacteria happened to be more significant for ecological analysis of water ecosystem. Despite relatively low bacterioplankton content during the study term, its reproductive activity was very high which is typical for ecologic productivity: the speed of growth reaches maximum when nutrients are abundant while population density is low. A very characteristic feature of spatial changes of the functional indices of bacterioplankton was the increase of production intensity after water discharge from Kiev hydroelectric station's dam, terrigenic sewage inflow at recreational sites and inflow of Kiev's industrial and household sewage from river Lybid. Another important ecological characteristic of bacterioplankton was evaluation of matter and energy flow based on productivity and trophologic studies. Consumption of bacteria by zooplankton was seen at all sites and increased significantly with the presence of disturbing factors as a response to quantitative and qualitative changes of feed. Consumption of bacterioplankton significantly influenced its production volume and intensity. At high significance, correlation coefficients between the values of bacterial consumption, growth speed constant and daily production were 0.79 and 0.89 respectively. It is, in fact, a manifestation of the well-known ecological provision: On one hand, the consumption of a certain link decreases its quantity; on the other hand it stimulates its reproduction and not only it does not decrease but it may actually increase its role in biotic rotation. The energy assimilated by bacteria was distributed as follows: 53% was used on constructive metabolism (P), 47% - on transpiration (R), 34% went to the next trophic level (G) and 19% accumulated with the dead organic matter. The P/R ratio was close to 1 except for the sites under the influence of disturbing factors where P was higher than R. It is known that maintaining the ecosystem at this state requires external energy inflow which, in our case, occurred from terrigenic sewage, tributaries and Kiev reservoir. Therefore, the indices of abundance are not enough to characterize the ecological state of bacterioplankton because they do not reflect the essence and the scale of bacterial community change under the influence of antropogenic factors. The use of functional and energy approaches is more informative for both evaluation of bacterioplankton's qualitative changes and ecological indication of water ecosystem in general.
DE: 0419 Biomineralization
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0465 Microbiology: ecology, physiology and genomics (4840)
DE: 0496 Water quality
SC: Biogeosciences [B]
MN: Fall Meeting 2005