Spatial distribution of Oreoleuciscus potanini in evenings in the Bayan Nur lake, Мohgolia

Вивчено розподіл алтайського османа в одному з озер Монголії улітку. Показники ехолота GPSMAP 178 фіксували цифровим фотоапаратом. Аналіз горизонтального розподілу риб показав, що максимальна концентрація та мінімальна варіабельність густоти ехомішеней відмічена на ділянках із глибинами 6–15 м. Аналіз вертикального розподілу розрідженого скупчення риб у пелагіалі виявив дві зони концентрації риб (2–4 м і від 10 м та глибше), між якими риби відмічаються поодиноко. Щільні скупчення риб, навпаки, локалізовані в основному у середніх шарах. Изучено распределение алтайского османа в одном из озер Монголии в летнее время. Показания эхолота GPSMAP 178 фиксировали цифровым фотоаппаратом. Анализ горизонтального распределения рыб показал, что максимальная концентрация и минимальная вариабельность плотности эхомишеней отмечались на участках глубиной 6–15 м. Анализ вертикального распределения разреженного скопления рыб в пелагиали выявил две зоны концентрации рыб (2–4 м и от 10 м и глубже), между которыми рыбы отмечаются одиночно. Плотные скопления рыб, напротив, локализованы в основном в средних слоях.Distribution of the altay osman in one of the lakes of Mongolia was studied in summer. Indications of the sonar GPSMAP 178 were fixed withdigital camera. Analysis of fish horizontal distribution had shown that the maximal concentrations and minimal variability of fish density were registered in the areas with depths of 6–15 m. Analysis of vertical distribution of pelagic rarefied fish aggregationshas revealed two fish concentration zones (2–4 m and from 10 m to deeper). Between those zones the fish scores were sparse. On the contrary, dense aggregationsof fishes locate at the middle water strata in the core.

New Sets of Primers for DNA Identification of Non-Indigenous Fish Species in the Volga-Kama Basin (European Russia)

Adequate species’ identification is critical for the detection and monitoring of biological invasions. In this study, we proposed and assessed the efficiency of newly created primer sets for the genetic identification of non-indigenous species (NIS) of fishes in the Volga basin based on: (a) a “long” fragment of cytochrome c oxidase subunit one of the mitochondrial gene (COI) (0.7 kb), used in “classical” DNA barcoding; (b) a short 3’-fragment (0.3 kb) of COI, suitable for use in high-throughput sequencing systems (i.e., for dietary analysis); (c) fragment of 16S mitochondrial rRNA, including those designed to fill the library of reference sequences for work on the metabarcoding of communities and eDNA studies; (d) a fragment of 18S nuclear rRNA, including two hypervariable regions V1-V2, valuable for animal phylogeny. All four sets of primers demonstrated a high amplification efficiency and high specificity for freshwater fish. Also, we proposed the protocols for the cost-effective isolation of total DNA and purification of the PCR product without the use of commercial kits. We propose an algorithm to carry out extremely cheap studies on the assessment of biological diversity without expensive equipment. We also present original data on the genetic polymorphism of all mass NIS fish species in the Volga-Kama region. The high efficiency of DNA identification based on our primers is shown relative to the traditional monitoring of biological invasions

Continental climate response to orbital forcing from biogenic silica records in lake baikal

CHANGES in insolation caused by periodic changes in the Earth\u27s orbital parameters provide the primary forcing for global ice ages1–6. But it is not clear to what extent the climates in continental interiors are controlled directly by regional variations in insolation and to what extent they are driven instead by the highly nonlinear response of the oceans and ice sheets. Here we investigate this question using the record of biogenic silica in Lake Baikal as a proxy for climate change in this high-latitude mid-continental region. We find a good correlation between this record and that of marine oxygen isotopes4. Over the past 250 kyr the Baikal record exhibits both a strongly nonlinear component (manifested in a 100-kyr periodicity) and weaker direct-insolation components (manifested in the 41-kyr (obliquity) and 23- and 19-kyr (precession) orbital cycles). These results show that even though extreme continental climates such as this are influenced directly by insolation variations, they are dominated by the nonlinear rhythm of the oceans and ice sheets. © 1995 Nature Publishing Group

Mesodictyopsis Khursevich, Iwashita, Kociolek and Fedenya

Volume: 55Start Page: 338End Page: 35