Ecological conditions

It is very fortunate for the rice producers of the United States that rice, as compared to most crops, is relatively free from insect pests. Metcalf and Flint (2b) list 30 species of insects as being injurious to corn, 20 to wheat, rye, and barley, 31 to leguminous crops, and 23 to cotton, as compared to but 4 for rice. The fact that rice fields are flooded a large portion of the growing season results in ecological conditions unfavorable to numerous insects that otherwise would probably attack this crop. 

Bacteria can be classified according to several characteristics, including their mode of nutrition, type of electron acceptor, ecological conditions, and dominance [41-43,45,47,49-53]. The following is abrief summary. 

For the inhabitants of the exclusion zone, situated in a forested region without well-developed economic and social infrastructures, it is of interest to estimate the relative contributions to internal exposure of forest food (berries and mushrooms) and conventional agricultural food (potatoes and milk). Some specialist studies have assumed that forest food represents only a small part of the diet of inhabitants of the exclusion zone, but we would suggest that in fact, it plays a major role. Typically, the consumption of forest food contributes 50% of the internal exposure dose, while for some critical population groups, it can exceed 80%. The definition of the spatial variation in pollution, the prevailing ecological conditions, and the diet should allow a scientifically-based prediction to be made of the internal exposure dose to the local population, and will help to identify the major risk factors within a certain time period following the Chernobyl catastrophe. 

Krejcl Z, Hanus L, YoshidaT, Braenden OJ, The effect of cHmatic and ecologic conditions upon the formation and the amount of cannabinoid substances in the cannabis of various provenance, Acta Univ Olomuc, Fac Med 74 147—160, 1975. 

Aquatic ecotoxicology evaluates the probability of an adverse impact of a substance on the aquatic environment at the present as well as in the future, considering the total flow into the system (Klein, 1999). It encompasses laboratory ecotoxicity tests on appropriate test organisms to explore relationships between exposure and effect under controlled conditions as well as studies of the effects of substances or effluents under a variety of ecological conditions in complex field ecosystems (Chapman, 1995). 

Zaitsev, Yu. P. (1992). Ecological condition of the Black Sea shelf near Ukraine s coast (In Russian). Gydrobiologicheskii Zhumal 28,3-18. 

Local variations in the vertical distribution of radionuclides are determined by both hydrological and ecological conditions. The correlation between these conditions is a function of the season. Table 6.12 gives estimates of the role of ecological processes in the formation of the vertical distribution of the radionuclear pollution of Arctic seas. These estimates show that the biological community plays a minor role in radionuclide transport from upper layers to the deep ocean. 

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