Zoologičeskij žurnal

Polychaete annelids are one of the main components of oceanic benthos, but little is known about their microbial symbionts. The purpose of this work is to study the microbiome associated with representatives of Terebellides cf. stroemii and to describe their lifestyle in the White Sea. To do this, the worms and their tubes were examined using light and electron microscopy, and the composition of the microbiome was studied by sequencing the hypervariable V4 regions of the 16S rRNA gene. The tubes of Terebellides cf. stroemii are shown to be loose and, most likely, temporary, whereas the worms dig actively into the ground, yet spending part of their time collecting food from the ground surface with the help of tentacles. Bacteria were found neither in integument cells nor in the intestinal epithelium. Phylogenetic and cluster analyses revealed significant differences in the taxonomic composition of the microbiomes of T. cf. stroemii worms from the soil microbiome and allowed us to determine specific components of the microbiomes of intestines and tentacles, whereas the microbiomes of bottom sediments and worm tubes appeared to be similar. The microbiomes of the tubes are dominated by Pseudomonadota, Desulfobacterota and Bacteroidota. While the intestines are home to Pseudomonadota, Actinomycetota, Bacillota, Cyanobacteriota, Chloroflexota and Planctomycetota, this bacterial community is very different from the microbiomes both of the surrounding sediment and the tentacles. The microbiome of the tentacles of T. cf. stroemii differs significantly from that of the surrounding soil, tube and intestine, as it contains Pseudomonadota, Bacillota and Bacteroidota, in addition to a significant number of representatives of the archaeal superfilium DPANN observed in two samples. Modern technologies for studying microbiomes demonstrate the presence of specific communities of microorganisms associated with the study species, with a combination of morphological and molecular methods being promising for studying the microbiomes associated with marine annelids and their functional relationships with the animals.

The genus Fenichelia (Oribatida, Micreremidae) is recorded from the Oriental Region for the first time. A new species – Fenichelia arborea sp. n. – is described, based on adults collected from tree branches of Dipterocarpus alatus in the Cat Tien National Park, Vietnam. The morphology of the gnathosoma and the identification of leg setae and solenidia are presented for the first time for a representative of this genus. A revised generic diagnosis of, an identification key to, as well as distribution and habitat data for the known species of Fenichelia are provided.

Successional changes in springtail communities were studied along a retreating Tsey Glacier at 2336 to 2071 m a.s.l. Springtails were collected from 10 sites of different ages ranging from 1 to 170 years. The sites covered the main stages of surface overgrowth, from a bare ground through a grassy-shrub stage to mixed and then mature pine forests. Springtails appeared already during the first year after the glacier’s retreat and were represented by a species of the genus Desoria, a peculiar inhabitant of bare rocky-sandy soils. During the first 7–14 years of succession, rapid changes in population and species composition repeatedly occurred. Both abundance and species diversity of springtails sharply increased at the grassy-shrub stage (14 years) and reached their maximum at later ones. Starting with this intermediate stage, springtail assemblages were primarily composed of widespread generalists belonging to euedaphic and hemiedaphic life forms. Beginning from this point, the pace of succession gradually slowed down. Approximately 100 years since, springtail communities reached a level of diversity similar to that found in mature mountain forest communities in the region. However, their species composition and structure remained quite distinctive. A comparison with similar foreign studies showed the composition of periglacial springtail communities to exhibit high-level regional specificity.

The numbers of waterfowl and shorebirds declining on a global scale is largely due to the reduction in wetland areas in the era of climate warming. Long-term monitoring data obtained in 1995–2020 in two Key Bird Areas of Russia of international importance, i.e. the Sulakskaya and Turalinskaya lagoons, the Republic of Dagestan, are presented, the transboundary populations of Anseriformes (Anatidae) taken as examples, Both model lagoons are located in one of Russia’s largest bottleneck places of the western Caspian flyways, where the fly routes of European and Asian migrants intersect. The Anseriformes model group, which includes 18 predominantly background species, was chosen based on their regular encounters during migration. According to the information on the ring returns obtained from the Research and Information Center for Bird Ringing at the Institute of Ecology and Evolution, Russian Academy of Sciences, a conditional outline of the generalized distribution range of Anseriformes was revealed, the faunogenetic basis of which is composed of widespread representatives of Arctic or Siberian fauna types. Based on all available data, including the information derived from literature sources, the geographic location both of populations and their regular migration areas was determined. The rating of 12 of all 18 study species was found to have significantly decreased, vs 2 that increased, and further 4 that remained stable. The resulting trends were synchronized with data available from literary sources on the same species of Anseriformes in their nesting areas. The coincidence of the corresponding trends with the distribution trends of the same anatid species in their nesting areas ensured the distance of distant populations of Anseriformes obtained along their flyways in the model lagoons to be correctly measured. This was found to correlate with the average monthly air temperatures in the autumn-winter period in the Primorskaya Lowland of Dagestan, 12 model species being associated with temperature fluctuations. The numbers of migratory populations of anatids in cold years are shown to lead to their increased migration in the study area, as a result the migration of migrants along the flight routes slowing down and their wintering places being changed. Correlation analysis showed a significant relation between the increased areas of Anseriformes wintering in the Caspian Sea with sea-level regression, in which the shallowing areas of marine waters limited the access of anatids to food resources (benthos). Three key factors determining the dynamics of a group of Anseriformes populations are discussed: hydroclimatic cycles, anthropogenic influence and foraging. A temporary ban on the hunting removal of 8 vulnerable species of anatids (the Greylag Goose, the Common Teal, the Garganey, the Gadwall, the Eurasian Wigeon, the Northern Pintail, the Northern Shoveler, and the Common Pochard) is proposed to be imposed in Siberia, Kazakhstan, the Urals Federal District, the Cis-Urals, the Volga region, and the Southern and North Caucasus federal districts until their populations become sufficiently restored.