Еколого-морфологічна структура мікрофітобентосу озера Тельбін

Abstract

У мікрофітобентосі оз. Тельбін встановлено основні еколого-морфологічні групи водоростей. Виявлено, що до їхнього складу входять не тільки бентонти, а й планктонти, що осідають на дно з товщі води, та перифітонти, принесені токами води з вищої водяної рослинності або твердих субстратів. З’ясовано, що в літній період планктонти та перифітонти відіграють основну роль у формуванні видового багатства мікрофітобентосу, через що альгоугруповання представлено альгоагрегацією – нестійкою сукупністю водоростей у біотопі, що вказує на несприятливі умови існування на дні для представників резидентної альгофлори.

The paper considers the findings of studies on ecological-morphological structure of microphytobenthos in Telbin Lake located in the residential community of Kyiv city. The research study aimed to distinguish ecological-morphological groups of algae in microphytobenthos of the human-impacted waterbody within the urban area and to evaluate the role of microphytobenthos structural components in forming a certain type of algal community. Microphytobenthos was sampled with the MB-TE microbenthometer within the littoral area at aquatic-vegetation-free sites and within the deep-water area of the lake. Algae sampling and laboratory processing of samples were performed in accordance with the methods generally accepted in hydrobiology. For diatoms identification permanent slides were made with special high-resolution mounting media. Ecological-morphological groups of benthic algae were distinguished considering the habitats of algae. The relative share in the microphytobenthos species richness was calculated for each group. The degree of human impact on the lake ecosystem was evaluated according to the proven method, consisting in distinguishing the total number of factors, which most frequently affect the lake ecosystem. The findings of studies on the ecological-morphological structure of microphytobenthos in Telbin Lake have made it possible to distinguish 7 ecological-morphological groups of algae. The species richness is mainly formed by periphytont and plankton, and benthonts are for the most part represented by the ecological-morphological group of eurytopic littoral diatoms. In the high-degree human impact waterbody (8 points) the share of benthonts’ major ecological-morphological groups in the species richness decreases in 1.6–2 times, and the shares of periphyton and plankton increase 1.3– 2-fold respectively, as compared with low-degree human impact waterbody (3 points). The resulting unstable algal community consisting mainly of species getting to the lake bottom from other habitats is defined as algal aggregation, which is indicative of unfavorable conditions for residential algal flora development. Various waterbodies of Ukraine can differ significantly in the environmental variables playing a determining role in microphytobenthos structure and abundance. Microphytobenthos may act as a reliable biological indicator of aquatic ecosystem’s disturbance caused by human pressure upon waterbodies, responding to such pressure with the transformation of its structural elements. For several waterbodies of Ukraine detailed analysis of microphytobenthos ecologicalmorphological structure made it possible to characterize bottom algal communities and to distinguish algal cenoses, which allowed to assess ecological state deterioration in different areas of the waterbodies under study. The information on the microphytobenthos structural components of urban lakes is scarce. Therefore, studying the ecological-morphological structure of microphytobenthos in various waterbodies within Kyiv city is of high importance.