%0 Journal Article %T Extrapolative Estimation of Benthic Diatoms (Bacillariophyta) Species Diversity in Different Marine Habitats of the Crimea (Black Sea) %A A. N. Petrov %A E. L. Nevrova %J International Journal of Biodiversity %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/975459 %X Benthic diatoms species richness was analyzed based on 93 samples collected at 8 areas of Crimea (Black Sea) on sandy/muddy bottoms within depth range 6每48ˋm. Totally 433 species were found. Expected species richness was estimated by application of Jack-knife -1 and -2, Chao-2, and Karakassis- estimators. Magnitude of , resulted from , displayed the most similar values to the observed species number ( ). Overestimation of (10每13%) occurred for small number of samples (<12), and slight underestimation (3每5%) occurred when sample numbers exceeded 40每43. The other estimators gave large overestimated results (Chao〞from 21 to 70% higher than , Jack-knife〞23每58%). The relationship between number of samples (X) and number of observed species (Y) was calculated considering all 93 samples: . Accordingly, not less than 10 samples are required for disclosing about 50% of the total species richness (433); to detect 80% (347 species) not less than 46 samples should be considered. Different configurations of method were applied to optimize its performance. The most precise results can be achieved when the calculation of the is based on sequences of randomized samples with sampling lags of 10 to 15. 1. Introduction Species richness is an essential attribute of a biological community and a widely used surrogate for the more complex concept of biological diversity. Quantitative change in species richness is an important characteristic underlying many biotic indices and integral assessment of community structure and condition in relation to habitat [1每4]. In the ecological study of benthic diatoms (Bacillariophyta), effective comparative assessment of the species structure of taxocene in various habitats, including protected marine areas, is a key problem that is important also to the establishment of conservation priorities. Therefore, the reliability and deviation of species richness measurements is one of the essential methodical tasks of diatomology that has been insufficiently studied as yet. The diatoms species richness may differ considerably even in adjacent sea bottom areas because of diverse environmental conditions and spatial microdistribution pattern of microalgae. In prognostic assessment of species richness and diversity of taxocene in heterogeneous biotopes, it is methodologically important to determine the relationship between sampling effort and the number of species found in these samples. Hypothetically, the larger is the number of samples, the larger is the number of detected species. In practice, however, only a reasonable minimum of samples, %U http://www.hindawi.com/journals/ijbd/2013/975459/