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Studies were carried out in 2000–2007 near Medusa Bay (73°21′N, 80°32′ E) and along the Agapa River (from 70°11′N, 86°15′ E. down to the mouth 71°26′ N, 89°13′ E), in the northwestern and central parts of the Taimyr Peninsula. White-fronted goose nests are usually spread in the tundra or placed in 1–3 nest colonies near nests or staging points of snowy owls, peregrine falcons, or rough-legged buzzards. The intent of white-fronted geese to breed near birds of prey or owls increases sharply when arctic fox numbers are high. In the area near Medusa Bay, white-fronted geese nest much closer to peregrine falcon nests than in the area along the Agra River. At the latter location, white-fronted geese lose the competition to red-breasted geese, which are more numerous here. Bean geese, in spite of their greater size and ability to protect their nests against arctic foxes, really tend to breed near peregrine falcons or buzzards, where they manage to compete with red-breasted geese. [ABSTRACT FROM AUTHOR]

Red-breasted goose colonies have been studied near Medusa Bay (73°21′N, 80°32′E), on the northwestern Taimyr Peninsula, and along the Agapa River (70°11′N, 86°15′E) down to its mouth (71°26′N, 89° 13′E), in the central Taimyr Peninsula. Red-breasted geese nesting near peregrine falcons are protected by the falcons from arctic foxes; however, they are sometimes attacked by the falcons themselves. In the colonies near peregrine falcon nests, the vast majority of goose nests were situated no farther than 100 m from the falcon nest. When food is abundant, falcons protect a larger area around their nest. The distance between the falcon nest and the surrounding goose nests is inversely related to the falcon’s activity. In years of higher falcon activity, falcons prevent red-breasted geese from nesting as close to their nest as in years of lower falcon activity. Additional stimuli are required for red-breasted geese to form colonies near rough-legged buzzard nests. The distance between snowy owl nests and red-breasted goose nests was smaller when arctic foxes were abundant than when they were scarce. [ABSTRACT FROM AUTHOR]

Waterborne radioactive releases into the Techa River from the Mayak Production Association in Russia during 1949-1956 resulted in downstream contamination of the river ecosystem. The discharged liquid waste contained both short-lived isotopes ( 95 Zr, 95 Nb, 103,106 Ru, 141,144 Ce, 91 Y, 89 Sr and 140 Ba with half-life from 3 days to 1.02 years) and the long-lived 90 Sr and 137 Cs (half-life - 28.79 y and 30.07 y, respectively). Even now, when two half-lives of 90 Sr and 137 Cs have passed, the contamination in the upper river region (about 70 km from the source of releases) is still relatively high. Current anthropogenic dose rates calculated for the fish of the Techa River depend on the distance along the stream and decrease from 150 to 3 μGy day -1 . Radiation exposure of fish is expected to have been much higher at the time of the releases. The aim of the study was to evaluate the dose rates for the most common fish species of the river, viz., roach (Rutilus rutilus), perch (Perca fluviatilis) and pike (Esox lucius), in the period of peak contamination of the upper reaches of the Techa River from 1950 to 1951. To achieve this objective, calculation of both internal and external dose rates was performed. For dose rate calculation, the contamination of the river compartments was modeled, body-size dependent dose coefficients were evaluated, morphometric data were analyzed. Maximum dose rates were obtained for roach; minimum - for pike, it depends on fish lifestyle (time spent at the bottom). In the period before September 1950, fish of the upper reaches are assessed to have been exposed to dose rates exceeding the screening level equal to 240 μGy day -1 . From September 1950 up to the end of 1952 the fish dose rates along the Techa River were found to be close to the UNSCEAR threshold equal to 9.6 × 10 3  μGy day -1 or even much more higher (up to 1.9 × 10 5  μGy day -1 ). Extremely high historical dose rates did not lead to the difference in fish size and fish growth rate currently observed in the Techa River and in the comparison waterbody (the Miass River). Discussion includes the description of radiation effects observed currently in the river fish. Today the effects observed in hematopoietic system may be the consequence of radiation exposure of fish over several generations. For example, long term dwelling of fish in the radioactively contaminated environment leads to their adaptation to chronic radiation exposure. At the same time, an increase their sensitivity and decrease their adaptive capacity to respond to other stress factors can be observed., (Copyright © 2019. Published by Elsevier Ltd.)

As a result of operation of the Mayak Production Association (Mayak PA), Chelyabinsk Oblast, Russia, an enterprise for production and separation of weapon-grade plutonium in the Soviet Union, ecosystems of a number of water bodies have been radioactively contaminated. The article presents information about the current state of ecosystems of 6 special industrial storage reservoirs of liquid radioactive waste from Mayak PA: reservoirs R-3, R-4, R-9, R-10, R-11 and R-17. At present the excess of the radionuclide content in the water of the studied reservoirs and comparison reservoirs (Shershnyovskoye and Beloyarskoye reservoirs) is 9 orders of magnitude for (90)Sr and (137)Cs, and 6 orders of magnitude for alpha-emitting radionuclides. According to the level of radioactive contamination, the reservoirs of the Mayak PA could be arranged in the ascending order as follows: R-11, R-10, R-4, R-3, R-17 and R-9. In 2007-2012 research of the status of the biocenoses of these reservoirs in terms of phytoplankton, zooplankton, bacterioplankton, zoobenthos, aquatic plants, ichthyofauna, avifauna parameters was performed. The conducted studies revealed decrease in species diversity in reservoirs with the highest levels of radioactive and chemical contamination. This article is an initial descriptive report on the status of the biocenoses of radioactively contaminated reservoirs of the Mayak PA, and is the first article in a series of publications devoted to the studies of the reaction of biocenoses of the fresh-water reservoirs of the Mayak PA to a combination of natural and man-made factors, including chronic radiation exposure., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A number of aquatic ecosystems were exposed to ionizing radiation as a result of the activities of the Mayak Production Association in the Southern Urals, former Soviet Union, in the 1950s. Currently, fishes inhabiting contaminated lakes are being actively studied. These investigations need dosimetric support. In the present paper the results of a pilot study for elaborating an EPR dosimeter which can be used for internal dosimetry in vitro are described. Biological hydroxyapatite is proposed here to be used as a detecting substance. More specifically, small hydroxyapatite grains are proposed for use as point detectors fixed in a solid matrix. After having been pelletized, the detectors were covered by Mylar and placed in the body of a fish to be stored in the fridge for several months. Application of the detectors for internal fish dosimetry demonstrated that the enamel sensitivity is sufficient for passive detection of ionizing radiation in fishes inhabiting contaminated lakes in the Southern Urals.

Planktonic communities of the Reservoir-9 (Lake Karachay, storage reservoir of liquid medium-level radioactive waste of the Mayak Production Association) are exposed to the severe radioactive forcing (in 2010 the total beta-activity of the water was 1.8 x 10(7) Bq/L, total alpha-activity was 1.1 x 10(4) Bq/L), aswell as to the chemical contamination (level of nitrates in water 4.1 g/L). The calculated values of the absorbed dose rate were 130 Gy/day for phytoplankton and 4.0 Gy/day for zooplankton. Extremely low species diversity, the overwhelming dominance of one species (phytoplankton is close to a monoculture of ubiquitous cyanobacteria Geitlerinema amphibium, zooplankton--to a monoculture of rotifers Hexarthrafennica), wide fluctuations in numbers of algae, a low number of zooplankton were the most substantial characteristics of the plankton communities in Lake Karachay. So, plankton communities status is a sign of environmental retrogress in this ecosystem.

Red-breasted goose colonies have been studied near Medusa Bay (73 degrees 21' N, 80 degrees 32' E), on the northwestern Taimyr Peninsula, and along the Agapa River (70 degrees 11' N, 86 degrees 15' E) down to its mouth (70 degrees 26' N, 89 degrees 13' E), in the central Taimyr Peninsula. Red-breasted geese nesting near peregrine falcons are protected by the falcons from arctic foxes; however, they are sometimes attacked by the falcons themselves. In the colonies near peregrine falcon nests, the vast majority of goose nests were situated no farther than 100 m from the falcon nest. When food is abundant, falcons protect a larger area around their nest. The distance between the falcon nest and the surrounding goose nests is inversely related to the falcon's activity. In years of higher falcon activity, falcons prevent red-breasted geese from nesting as close to their nest as in years of lower falcon activity. Additional stimuli are required for red-breasted geese to form colonies near rough-legged buzzard nests. The distance between snowy owl nests and red-breasted goose nests was smaller when arctic foxes were abundant than when they were scarce.