An analysis of 1000 individuals of roach has revealed 40 morphological modifications in the intermediate region of vertebral column. The following types are described: L is the first vertebra with the single parapophysis on the left side, R is the first vertebra with the single parapophysis on the right side, Tw is the first vertebra with the right parapophysis and the second with the left one, and Cn is the vertebra with the single parapophysis in the central part of the region. Throughout the sample, the number of phenes of symmetric type S with Λ and/or A parapophyses is almost 1.5 times higher than L and R types, but their incidence is 75
A comprehensive study of the charophyte flora of Lake Sevan, Gegharkunik province, Armenia, was conducted through 2023 fieldwork and examination of herbarium collections. Eight species were identified: Chara aspera and Tolypella glomerata (new national records, the former also new to the Caucasus), C. canescens, C. contraria, C. globata, C. globularis, C. papillosa, and C. uzbekistanica. Lake Sevan currently supports 8 of the 10 species known from Armenia, indicating its role as a regional biodiversity hotspot and refuge for charophytes. These new data provide an updated baseline for future monitoring of Lake Sevan’s biodiversity during the ongoing rise in water level.
The effects of the heavy metals cadmium (Cd2+), copper (Cu2+), and zinc (Zn2+) on the intensity of aerobic metabolism (respiration) in the bivalve mollusk Dreissena polymorpha (Pallas, 1771), quantitatively assessed by the oxygen consumption rate, were studied experimentally. Short-term toxic exposure to heavy metals was found to reduce the oxygen consumption rate in mollusks, whereas prolonged exposure led to shell-valve closure and complete suppression of aerobic respiration. Cd2+ is the most toxic to the mollusks; a concentration-dependent effect has been shown for this ion. Changes in the oxygen consumption rate in mollusks are proposed for use as a biomarker of their functional state and for ecotoxicological assessment of habitat quality.
The present endeavour revealed the discernible phytoplanktonic heterogeneity in relation to the water quality changes in jute retting ponds of Brahmaputra-Beki doab both before and after retting. A total of 111 microalgal species belonging to 6 classes, 21 orders, 36 families and 58 genera were recorded among which, 85 algal taxa showed occurrence in pre-retting while only 64 in post-retting water. The current study also enumerated a total of 38 ecologically indifferent microalgal species in both the pre and post retting conditions. The class Zygnematophyceae (27) and Chlorophyceae (20) dominated in pre-retting water, in contrast Bacillariophyceae (22) and Cyanophyceae (15) showed dominance in post-retting water. A significant variation in water physicochemistry was also noticed in both the phases, where BOD, TDS, Free CO2, Potassium, Total Nitrogen, COD, Turbidity, Phosphate, Chloride, Total Alkalinity increase up to 92.84, 78.30, 75.47, 70.81, 70.61, 61.42, 54.29, 50.08, 32.05 and 24.57
The first synchronous data on content of chlorophyll a in the pelagic and benthic zones of small lakes in Western Siberia (Tyumen Oblast, Russian Federation) are presented. The water bodies differed in the trophic state index and water pH. The average chlorophyll concentrations in plankton of mesotrophic and eutrophic lakes are 5.5 ± 0.8 and 33.5 ± 3.8 μg/L, respectively, and the concentrations of chlorophyll a with pheopigments in bottom sediments are 185 ± 59 and 202 ± 113 μg/g dry sediment, respectively. According to the pigment content in bottom sediments, the trophic states of the benthal and pelagial are not similar. According to the chlorophyll content in plankton, the number of mesotrophic and eutrophic lakes in the studied sample is similar. The trophic diversity of small lake benthal formed by sapropel and sandy and clayey silts includes all categories of trophy (from oligotrophic to hypertrophic) with a predominance of hypertrophic biotopes.
