At the SR-XRF stations (X-ray fluorescence analysis using synchrotron radiation) of the VEPP-3 and VEPP-4M storage rings of the Budker Institute of Nuclear Physics (BINP), Siberian Branch, Russian Academy of Sciences, a test quantitative analysis of chemical elements in the soft tissues of fish is carried out and one-coordinate scanning of fish scales is performed. In the studied samples, the concentrations of 20 chemical elements are determined and differences are identified depending on the type of tissue analyzed, the growth conditions (natural/aquaculture), gender, and taxonomic affiliation of the analyzed individuals. The analysis of biological tissue with minimal sample preparation and the ability to study large samples is an undeniable advantage of the SR-XRF method and can be an effective tool for the environmental monitoring and control of growing process of aquaculture fish products.

The high-resolution biochemical records (SRXRF, ICP-MS and FTIR analyses) of bottom sediments were used for the reconstruction of clastic flux into Lake Baikal via the Barguzin River as moisture and glacier indexes from 1631 ka BP. According to the obtained data, proxies of a high supply of clastic flux by the river are high: the content of feldspar and LREE/HREE, Rb/Sr and Th/Mo ratios. We sampled a sediment core extremely close to the estuary of the Barguzin River. It seems that the water budget of the Baikal tributaries dramatically reduced ca. 34-30 ka BP, and the lake water level was minimum (less than 35-40 m compared to the present) for the last 34 ka. The lake water level has gradually increased from ca. 30 to 25-23 ka BP, and it was likely linked with the activity of the East Asia Monsoon. The very contrasting changes in chemical and mineralogical records were ca. 29.5 ka BP, and these changes were very likely associated with the Heinrich-3; however, there were no significant changes in the records around the Heinrich-2. Our records revealed some intensification of the clastic flux of the Barguzin River into the Barguzin Bay ca. 25-23 ka BP. The Baikal event ca. 21.5-22.5 ka BP was characterized by a sharp reduction of the influx of clastic material into the Barguzin Bay. The time span of 19.5-18 ka BP was the last time that the Barguzin River inflow increased during the Late Pleistocene. This increase in the water budget was at arid regional conditions, and we assumed it could occur due to the contribution of meltwater from glaciers of the Barguzin Ridge. It is most likely that at the regional Late Pleistocene/Holocene transition (around 12-13 ka BP), a rapid rise of the water budget of the Barguzin River occurred, while the lake level was not high, and the sediments deposited from 12(13)-16.5 ka BP could be directly eroded by a kill of the Barguzin River. In general, the obtained records show that an increase in the water budget of the Barguzin River was gradual. The duration of high inflow into the Barguzin Bay was ca. 1.5 ka, while the reductions of this inflow were dramatic.

Here we report new data describing the biodiversity of phytobenthic communities based on DNA-metabarcoding using the 18S rDNA marker and the Illumina MiSeq system. The study was initiated due to the blooming of f ilamentous algae (mainly of the genus Spirogyra) and cyanobacteria in the coastal zone of Lake Baikal under climate change and anthropogenic impact. The composition and taxonomic diversity of algae and other organisms associated with them on different sites of Lake Baikal (near Bolshoi Ushkaniy Island, in Listvennichny Bay) and in the Kaya (within the city of Irkutsk, located in the same drainage basin as Lake Baikal) were determined using DNAmetabarcoding. About 15 thousand reads of the 18S rRNA marker were obtained by applying NGS (next-generation sequencing). The species of algae dominating in the number of reads, as well as the diff icult-to-identify taxa (Stramenopiles, Alveolata, Euglenozoa, Chromista, Rhizaria, Amoebozoa, etc.), which play an important role in the functioning and formation of the structure of algal communities, were revealed. The Shannon index of the communities studied ranges from 1.56 to 2.72. The advantages and weaknesses of using DNA-metabarcoding based on the 18S rRNA gene fragment for studying the structure of algal communities are shown. The advantage of this method is the possibility to more fully determine the diversity of eukaryotes taxa, which are diff icult to identify by morphology, without involving a large number of specialists, while the disadvantage of the method is the distortion that may occur during the PCR. Here, ways of solving this problem are proposed. The results of the study show that the analysis of the minor component of the eukaryotic community in samples (organisms with low biomass) consisting of a mixture of multicellular and unicellular organisms requires a read-depths of at least 100,000 sequences per sample. In general, the DNA-metabarcoding method is recommended for studying the structure of algal communities and eukaryotes associated with them.

Abstract. High-resolution seismic data (65 km profiles) have been used to study the sedimentary infill of Ivan-Arakhley lake system (Lakes Arakhley, Ivan and Shakshinskoe). It found that full limnological cycle bears only sediment cover of Lake Arakhley. Total sediment infill of Lake Arakhley is 6-7 m, and it was be divided into three sequences. The uppermost ~2.5 m of sediment cover was presented by a normal lacustrine filling. Lacustrine sediments began to form ca. 21 cal. ka BP. The lake was almost dried during the regression occurred between ca. 3 and 2.6 cal. ka BP.

The paper discusses the use of catamaran-type ultra-small unmanned vessels for studying lakes, rivers and different offshore areas. The key features of a surface vessel designed in Irkutsk Technical University are presented. The article describes major systems of the vessel and concepts of autonomous functioning and remote control. The apparatus can fulfil automatically mapping, searching of sunken objects, hydroacoustic scanning of bottom relief and underwater video recording without the use of additional boats. It is capable to inspect 100 linear kilometers (∼15 km 2 ) of the water area per one day. The use of solar panels and Li-ion batteries charged during a single sunny day allows it to work for several days without use of any external sources of energy for recharging. All systems have been checked and debugged in the laboratory and the designed vessel was tested in Irkutsk reservoir. The field testing showed that the error of coordinates determining was within 2 meters. The planned and actual routes almost coincided with an accuracy better than 3 meters.

Lake Baikal is the largest fresh water reservoir of our planet and a unique natural site included in the UNESCO World Heritage List. Meanwhile, Baikal is not only Russia’s largest freshwater fishing reservoir. Large-scale commercial fishing started here at the beginning of the 19th century and, with small breaks caused by bans imposed on industrial fishing due to depletion of valuable commercial fishery species stock, continued until October 2017, when once again restrictions in the fishing industry were imposed. One of the reasons for this was the increasing of the illegal unreported and unregulated fishing which led to depletion of harvestable stock of omul. However, these restrictions neither eliminated extensive unreported fishing, nor solved the problem of rapid fish stock rebuilding in the unique lake. Using methods of mathematical analysis and modeling this article examines factors facilitating breach of law in the fishing industry and unreported fishing for Baikal omul. The article provides a brief characteristic of the Baikal oldest Malomorsky fishing area as well as an eco-economic assessment of the possibility to rebuild the fishing stock within this water zone taking into account the increasing tourist flow in the Baikal region.

In the present study, we have reconstructed glacier dynamics based on the high (1-0.5 mm) resolution X-ray fluorescence spectrometry scanning, the Fourier-transform infrared technique and C-14-dating used in the analyses of the lake bottom sediments, fluvioglacial deposits and a peat bog situated on East Siberian Mountains (East Sayan, Baikal, Barguzin and Kodar Ridges) between 51.723 degrees N, 100.601 degrees E and 56.885 degrees N, 117.580 degrees E. We have found what the largest glacier deposits on the Baikal shoreline, so-called Tompuda end moraine, formed in two stages. The first stage occurred until ca. 12 cal ka BP; then, there was a short pause. The second stage ended by 9.5 cal ka BP. Azarova glacier (Kodar Ridge) retreated upwards the Kodar Ridge by ca. 11 cal ka BP. It may indicate that the Bolling-Allerod warming was very evident, and it was a trigger for these deglacial events in East Siberia. It is most likely that "remains" of the Late Pleistocene glaciers were cardinally shrunk or fully disappeared during the Holocene Thermal Optimum in the southern part of East Siberia. Climate conditions were suitable for glacier formation after 3 cal ka BP. However, if there were new glaciers in the Middle Holocene, their sizes were likely to be less than 1 km(2). For this reason, these glaciers should have completely melted during the Roman and Medieval Warm Periods. It is most likely, small glaciers observed at present in the south of East Siberia were mainly formed during the Little Ice Age.

In this paper, we carry out an isotopic study to learn about the diet and mobility patterns of the human groups that inhabited different areas and environments of western Catamarca, Argentina, over almost 2500 years. We present and discuss the results of the isotopic composition of 26 bioarchaeological remains (δ13C and δ15N on bone collagen, and δ13C and δ18O on bone apatite) with their respective calibrated absolute dates, from different settings and elevations of the province of Catamarca. They account for the sociocultural development of both the first agropastoral village societies and the Inca society. We also present the regional isotopic context of autochthonous animal and plant food resources. The isotopic composition (δ13C and δ15N on bone collagen) of 47 samples of pre-Hispanic camelids recovered from archaeological sites located at different altitudes of the Fiambalá and Chaschuil regions are studied and discussed. In addition, the δ13C values of 52 native modern and archaeological plant samples are compiled, including samples from the region as well as information from the bibliography. Finally, isotopic analyses of water samples (δ18O) recovered from different environments in the study region are also shown. The data from δ13C and δ15N on bone collagen and δ13C on bone apatite show a high variability of the human diet of the populations of western Catamarca, and suggest that the societies that inhabited the region during the first millennium AD had a balanced diet that combined proteins and carbohydrates, while those dated after the thirteenth century AD reduced their protein intake, which would have significantly affected their health status. The first trends in the δ18O values indicate that individuals had low mobility patterns during their lives, except for some unusual cases of possible non-local individuals.

In this study, we analysed a 64 cm long sediment record from Lake Aunakit located on the Kropotkin Range (East Siberia, Russia) for subfossil diatoms and chironomids to provide an improved reconstruction of the environmental changes in the area for the past 4.2 ka. Diatom record is divided into four zones (0-0.84, 0.95-1.25, 1.3-2.0 and 2.0-4.2 ka BP). Duration of chironomid record is 1.8 ka, and this record is divided into five zones 1.8-1.5, 1.5-1.4, 1.4-1.25, 1.25-0.6, and 0.6-0 ka BP.

The chemical composition and current state water quality of the Selenga River and its tributaries in Mongolia are considered in this article based on the hydrochemical studies carried out in July, 2013-2014. The observed changes in the chemical composition of the water resulted from natural and anthropogenic factors are analyzed. It is shown that water quality of the Selenga River and its tributaries worsened because of the entering of polluting components from the catchment area of Ulaanbaatar city and its wastewater. No influence of the wastewater from the Erdenet Ore-Dressing Plant (EODP) on the content of the trace elements in the water of the Orkhon and Selenga Rivers is revealed.

This paper studies the formation of the sediment cover in Lake Gusinoye. For this purpose, we used high-resolution seismic data. Depression of Lake Gusinoye has a tectonic origin; however, there is no evidence of recent tectonic activity. Sediment thickness in Lake Gusinoye is less than 9 m, and its history is short (<35-45 ka). In addition, seismic stratigraphy records contain three contrasting episodes when the lake level dramatically decreased. It is very likely that there were also other shorter episodes of low-level stands. Thus, seismic structures of lakes Gusinoye and Kotokel have a strong resemblance, and it is most likely that their history began at the same time, ca. 40 ka BP.

This paper describes variability in trends of tree growth at tree-line locations of the Kolar and East Sayan Ridges in the high latitudes of Eurasia (East Siberia), providing a wide regional comparison over a 500-year period. The study focuses on the nature of local and widespread tree-growth responses to the Little Ice Age and Recent Warming climate changes. We found that tree-growth in studied areas mainly depended on June temperatures. Changes in June temperature were more pronounced in the Kolar Ridge compared to the East Sayan Ridge. In general, summer temperature regimes were more unstable during the Recent Warming, compared to the Little Ice Age.

Undoubtedly, the study of the Planet’s climate is one of the fundamental topics for elaboration of strategies for life support of the Earth’s population. The following questions arise: i) what is the spatial pattern of intensity of these changes; ii) what is the response of the regions to climatic changes; iii) what is the critical line when changes in the ecosystem are irreversible; iv) what are causes and mechanisms of these changes; v) what is the human role in these processes; and vi) which tendencies should be expected in climate changes in the nearest future? After answering these questions, a logical question is put forward: how unique is “the climatic landscape” of the recent decades compared to the previous epochs, and are all regions similarly sensitive to climatic changes? The challenge is how to describe these changes and which methods to use in order to obtain more reliable data. More generally and despite some problems, the studies indicate the value of combining limnological and palaeolimnological records in reconstructing lake history and in disentangling the changing role of different pressures on lake ecosystems.

The world’s freshwater ecosystems, sources of drinking water, are threatened by eutrophication. Many studies show that global warming leads to changes in aquatic ecosystems. Recently, eutrophication signs have been recorded in Lake Baikal, the world’s largest and deepest lake containing 20% of the world’s fresh water reserves. We have analysed long-term changes of the most sensitive natural factors (air and water temperature, wind regime, precipitation and solar radiation) and revealed their potential impact on emergence of unfavourable signs in the shallow zone of Lake Baikal. The main causes of adverse ecological processes are elevated temperatures of air and coastal water, reduced amount of precipitation, weakening of wind flows, and water exchange processes, and as a result, reduced self-purification. The highest number of anomalous climate changes has been recorded in the XXI century. Moreover, the years of the past decade were the most favourable for emergence of adverse processes in the lake (outbreak of rapid growth of algae and aquatic vegetation, rotting of their remains at the bottom and on the shores of the lake, etc.). Climatic factors will continue causing adverse effects in the shallow zone of Lake Baikal.

Technique for estimation of contents of the major components of lake bottom sediments using single peak analysis procedure has been developed. The technique allows estimation of biogenic silica (BSi), total inorganic carbon (TIC), total organic carbon (TOC) and quartz and feldspars content in bottom sediments. The calibration models are based on the following spectral regions: bands at 646 cm−1 (feldspars), 695 cm−1 (quartz), 874 cm−1 (TIC); the range from 818 to 835 cm−1 (BSi), the range of C–H vibrations (2800–3000 cm−1) (TOC). The technique has been probed for a number of Eastern Siberian lakes and results are compared with the data of other methods. It has been shown that the use of single peak analysis procedure allows very rapid FTIR estimation of the major components content in bottom sediments with accuracy, which is acceptable for many tasks.

We performed a regional analysis of the effect of anthropogenic (acid precipitation) and natural (climatic changes, endogenous methane) factors on the hydrochemical composition and phytoplankton of mountain lakes in East Siberia for the last 210 years. The lacustrine diatom community responded to the intense acid precipitation that led to the acidification of lakes in Europe and North America in 1950–1985: Cyclotella-complex was partly replaced by more pH-tolerant species of diatoms, such as Aulacoseira lirata, A. italica, and Tabellaria flocculosa. This anthropogenic impact, however, was not dramatic for the ecosystem of mountain Lake Oron. The diatom records distinctly show a tendency for the reduction of lacustrine-alga population since the end of the Little Ice Age. We assume that the decrease in the Oron bioproductivity was mainly due to a deficit of nutrients caused by the inflow of ultrafresh waters from the thawing glaciers, snow patches, and seasonal snow cover of the Kodar Ridge during the Recent global warming in the Northern Hemisphere. In addition, the changes in the lake ecosystem might have been accelerated by emissions of endogenous methane.

High-resolution seismic data have been used to study the sedimentary infill of Lake Oron. We have tested the idea that glacial Lake Vitim could be formed when glaciers descending from the Kodar Mountains blocked the Vitim River at Lake Oron. The five seismic facies types (shallow, pelagic, mudslide and turbidite, rock-sandslide, and alluvial or glacial fan facies) and five seismic units were identified in the sedimentary infill of Lake Oron. However, features that could represent moraines were not observed on the seismic profiles and along the shoreline of Lake Oron. It is very likely that terminal moraines did not dam the Vitim River up to 840 (60) m a.s.l at the end of the last glacial maximum (LGM). We assume that the Oron depression was mainly dry and glaciers lobes could be located close to the eastern edge of Lake Oron in valleys of the Sygykta, Kultushnaya, and Kamennaya Rivers during the LGM. Intensive inflow of meltwater and river input into Lake Oron began since ca. 18 ka BP. After ca. 5 ka BP, the supply of surface water into the lake sharply reduced.

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids found in several environments, including soils, rivers and lakes, whose distribution varies with temperature and pH, although this dependence is apparently not the same for the different environments. Mixing of brGDGT sources may thus complicate palaeoenvironmental reconstruction. The extent to which brGDGTs in a lake outflow reflect the distribution delivered by upstream rivers was studied for Lake Baikal (Russia), one of the largest freshwater lakes worldwide. Fifteen brGDGTs in suspended particulate matter (SPM) of the Selenga River and its outflow from the lake were quantified. The river and lake SPM had rather different distributions. The riverine distribution was still apparent in the SPM of the lake surface water 5 km from the river mouth, but shifts in the distribution were already apparent in the SPM of the surface water after 1 km. Based on the brGDGT distributions of the SPM of the Selenga outflow and that of the lake, conservative mixing between the river and the lake brGDGT distributions could not fully explain the observed shifts in distributions. Both preferential degradation and in situ production of brGDGTs in the surface and, especially, bottom water of the river outflow were potentially responsible. This implies that a riverine lipid distribution delivered to a lake can be modified prior to being transported downstream. The lacustrine brGDGT distribution, that possibly could have reflected a mixture of mountainous and Selenga River SPM, was not recognized in downstream Yenisei River SPM. The watershed of Lake Baikal thus does not seem to contribute to the brGDGTs transported to the marine system. As many large rivers have major lakes in their watershed, this has implications for palaeoclimate reconstruction from river fan sediments globally. (C) 2015 Elsevier Ltd. All rights reserved.

We present results of study of the bottom sediments of proglacial Lake Ekhoi, which is fed with the Peretolchin Glacier meltwater (East Sayan). The bottom deposit sequence, formed from 1885 to 2013, was investigated with a year-season time resolution, using X-ray fluorescence with synchrotron radiation (with and without scanning), the Fourier-transform infrared (FTIR) analysis, and color processing of core photos. The depth-age model of the core was based on counting of annual laminate layers with control by Pb-210, Cs-137, U-238, and Ra-226 chronology. Intense glacier thawing was calculated from the amount of clastic matter supplied by the glacier meltwater into the lake. The elemental composition of the bottom sediments includes three groups reflecting periods of displacement of the glacier front and the intensity of evolution of aquatic biota. The first group of elements (Ca, K, Ti, Fe, and Mn) characterizes the supply of clastic matter without serious changes in the glacier edges. The second group (Ni, Cu, Br, and U) is responsible for the intensity of evolution of aquatic biota. Finally, the third group (Rb, Sr, Zr, Nb, Y, and Th) can describe the intensity of displacement of the glacier front. Intensive glacier thawing has proceeded since 1920; however, the glacier retreat was insignificant till 1947. From 1947 to 1970, the glacier rapidly retreated, especially in the period 1953-1970. This was induced by steady high regional summer surface temperature in 1938-1970. The following glacier retreat was during 1980-2000, synchronously with the global temperature anomaly in the Northern Hemisphere. Since 2000, the melting has slowed. (C) 2015, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.

Results from studying the bottom sediments of proglacial Lake Ehoy, deposited by meltwaters of the Peretolchin Glacier in the Eastern Sayan Ridge, are presented. The bottom sediments formed between 1885 and 2013 are investigated with a time resolution of years and seasons by means of X-ray fluorescence with synchrotron radiation in the scanning and traditional modes (SR-XRF scanning, SR-XRF), infrared spectroscopy analysis, and the color processing of core photographs.