Водно-осажденная сера вулканов Головнина и Менделеева (остров Кунашир, Южные Курильские острова, Россия)

Research subject. Hydrothermal deposits of Golovnin Caldera. Aim. To study the epithermal volcanogenic ore formation. Key points. Until now, there has been a consensus on the exogenous sedimentary (colloidal) genesis of sulfur in volcanic lakes. Our observations and microstructure studies indicate the presence of sulfur melt at the bottom of Kipyaschee Lake. Drops of this melt are carried to the surface of the lake as part of a light gray foam. The significant differences of sulfur spherules in the concentration of sulfide mineralization, in its composition, as well as in the presence or absence of numerous opal inclusions are most simply explained by the capture of droplets in various parts of the sulfur melt and their subsequent movement by a gas stream passing through the melt. Elemental sulfur condensate is formed in bottom sediments as a result of forced cooling of endogenous gas flows by lake water. The main condensation of sulfur occurs here (96% or more of the total potential of fluid sulfur). Residual condensation of sulfur occurs in the aquatic environment. Finely dispersed sulfur condensate in a mixture with water is unstable and breaks down over time with the release of hydrogen sulfide and the formation of sulfurous and sulfuric acids. The activity of bottom hydrotherms and coastal unrest prevents the formation of colloidal sulfur sediment at the bottom of lakes. In the crater depressions at the bottom of the lakes of the Golovnin Caldera, sulfidization of its melt occurs simultaneously with the condensation of sulfur itself. Gravitational deposition of sulfides in the sulfur melt leads to their enrichment of the root parts of crater depressions, where pyrite ore bodies are formed in real time. Terrestrial sulfur deposits, together with the modified rocks overlying them, demonstrate the full profile of endogenous apical oxidation under gas-hydrothermal action: sulfur and sulfur-opal rocks up the section are replaced by gypsum-jarosite rocks and, further, by an “iron hat” of limonite-cemented breccias of the dome mantle. Conclusions. Observations, microstructure studies and molecular chemical modeling indicate the endogenous condensate origin of ore sulfur in the Golovnin Caldera and exclude its exogenous sedimentary genesis.

The dynamic watershed acid‐base chemistry model of acidification of groundwater in catchments (MAGIC) was used to calculate target loads (TLs) of atmospheric sulfur and nitrogen deposition expected to be protective of aquatic health in lakes in the Adirondack ecoregion of New York. The TLs were calculated for two future dates (2050 and 2100) and three levels of protection against lake acidification (acid neutralizing capacity (ANC) of 0, 20, and 50 μeq L−1). Regional sulfur and nitrogen deposition estimates were combined with TLs to calculate exceedances. Target load results, and associated exceedances, were extrapolated to the regional population of Adirondack lakes. About 30% of Adirondack lakes had simulated TL of sulfur deposition less than 50 meq m−2 yr to protect lake ANC to 50 μeq L−1. About 600 Adirondack lakes receive ambient sulfur deposition that is above this TL, in some cases by more than a factor of 2. Some critical criteria threshold values were simulated to be unobtainable in some lakes even if sulfur deposition was to be decreased to zero and held at zero until the specified endpoint year. We also summarize important lessons for the use of target loads in the management of acid‐impacted aquatic ecosystems, such as those in North America, Europe, and Asia.

New potential markers for the detection of boldenone misuse

We report herein the results of CO2 efflux surveys carried out at Cuicocha and Quilotoa volcanic lakes (Ecuador) with the aim of evaluating the temporal variation of diffuse CO2 emission and its relationship with volcanic activity during 2012-2018 for Cuicocha and 2014-2018 for Quilotoa volcanic lakes. Cuicocha and Quilotoa are the two most active volcanic lakes in Ecuador, and their monitoring is a priority task due to a considerable population density around both lakes. CO2 efflux measurements have been conducted at the surface of the lakes by means of the floating accumulation chamber method. To study the possibility of water stratification and CO2 accumulation in the lakes, vertical profiles of the water column were also conducted at Cuicocha (max. depth 80 m) and Quilotoa (max. depth 170 m) volcanic lakes in 2017 and 2018 respectively. The chemical and isotopic data shows that the lake water receives injections of deep hydrothermal water and gases during periods of intense volcano-seismic unrest. The distribution of the dissolved gas composition along the vertical profiles revealed that CO2 is the most abundant gas species. The carbon isotope signature indicated a clear endogenous origin for CO2, with a greater contribution in the stratification zone in both lakes. The computed diffuse CO2 output for Cuicocha volcanic lake (3.95 km2) showed a range from 53 to 652 t·d-1 for the period 2006-2018, while for Quilotoa volcanic lake (3.50 km2) from 141 to 536 t·d-1 for the period 2014-2018. Between the end of 2011 and the beginning of 2012, an increase in the seismic activity with an episode of long-period seismicity was recorded in Cuicocha volcanic lake, coinciding with the maximum value of diffuse CO2 emission registered in this study. A bathymetric study was carried out in Quilotoa in 2017, giving further information about the degasification processes and the morphology of the lake bottom. This work demonstrates the need to conduct regular surface degassing studies as an important volcanic surveillance tool to understand the processes that take place in the magmatic-hydrothermal system, to be able to better forecast future episodes of volcanic unrest, and to mitigate volcanic risk.

There are hundreds of volcanic lakes around the world that represent an important hazard due to the potential occurrence of phreatomagmatic or limnic eruptions. Variations in geochemical and geophysical parameters could help to identify potential risks for these events. Cuicocha and Quilota volcanic lakes, located at the North Andean Volcanic Zone of Ecuador, are geologically young, with gas emissions manifested mainly as CO2via bubbling gases. Both lakes present a limited monitoring record. Therefore, volcanic monitoring is a priority task due to the potential hazard they represent by the possibility of water stratification and CO2accumulation. During 2012-2018 period, geochemical investigation based mainly on diffuse CO2surveys and analyzing the chemical and isotopic composition of bubbling gases has been carried out at Cuicocha and Quilotoa lakes. Additionally, vertical profiles of water columns were conducted in both lakes to investigate the possibility of water stratification and CO2accumulation in the lakes. A bathymetric study was also carried out in Quilotoa in 2017, giving further information about the degasification processes and the morphology of the lake bottom. The computed diffuse CO2output for Cuicocha volcanic lake (3.95 km2) showed a range from 53 to 652 t d−1for the period 2006–2018, with a maximum value in 2012, coinciding with a maximum of the3He/4He ratio measured at the bubbling gases and an increase in the seismic activity with an episode of long-period seismicity recorded in 2011–2012. For Quilotoa volcanic lake (3.50 km2) diffuse CO2output was estimated between 141 and 536 t d−1for the period 2014–2018. The chemical and isotopic data show that Cuicocha has a chemical composition typical of worldwide superficial shallow waters and aquifers, while Quilotoa shows a chemical composition typical of crater lakes in active volcanic systems. The distribution of the dissolved gas composition along the vertical profiles shows the existence of different water masses in both lakes, with an increase in the concentration of dissolved gases with depth. The carbon isotopic signature indicates an endogenous origin of the CO2, with a greater contribution in the stratification zone in both lakes. This study shows methods applicable to other volcanic lakes of the world to monitor their activity and potential risks.

We report herein the results of CO2 efflux surveys carried out at Cuicocha and Quilotoa volcanic lakes (Ecuador) with the aim of evaluating the temporal variation of diffuse CO2 emission and its relationship with volcanic activity during 2012-2018 for Cuicocha and 2014-2018 for Quilotoa volcanic lakes. Cuicocha and Quilotoa are the two most active volcanic lakes in Ecuador, and their monitoring is a priority task due to a considerable population density around both lakes. CO2 efflux measurements have been conducted at the surface of the lakes by means of the floating accumulation chamber method. To study the possibility of water stratification and CO2 accumulation in the lakes, vertical profiles of the water column were also conducted at Cuicocha (max. depth 80 m) and Quilotoa (max. depth 170 m) volcanic lakes in 2017 and 2018 respectively. The chemical and isotopic data shows that the lake water receives injections of deep hydrothermal water and gases during periods of intense volcano-seismic unrest. The distribution of the dissolved gas composition along the vertical profiles revealed that CO2 is the most abundant gas species. The carbon isotope signature indicated a clear endogenous origin for CO2, with a greater contribution in the stratification zone in both lakes. The computed diffuse CO2 output for Cuicocha volcanic lake (3.95 km2) showed a range from 53 to 652 t·d-1 for the period 2006-2018, while for Quilotoa volcanic lake (3.50 km2) from 141 to 536 t·d-1 for the period 2014-2018. Between the end of 2011 and the beginning of 2012, an increase in the seismic activity with an episode of long-period seismicity was recorded in Cuicocha volcanic lake, coinciding with the maximum value of diffuse CO2 emission registered in this study. A bathymetric study was carried out in Quilotoa in 2017, giving further information about the degasification processes and the morphology of the lake bottom. This work demonstrates the need to conduct regular surface degassing studies as an important volcanic surveillance tool to understand the processes that take place in the magmatic-hydrothermal system, to be able to better forecast future episodes of volcanic unrest, and to mitigate volcanic risk.

Subaqueous hot springs in Köyceğiz Lake, Dalyan Channel and Fethiye-Göcek Bay (SW Turkey): Locations, chemistry and origins

Summary The morphometry, environmental conditions, and some physical and chemical data are given for twenty‐four New Zealand lakes: seven are in the southern part of the South Island, the others, excluding Lakes Waikaremoana and Waikareiti, are in the “thermal region” of the central North Island. These lakes form two separate groups and include the largest and deepest lakes in both islands. The lakes in which stratification was established were found to belong to the class known as warm monomictic Two lakes, Rotorua and Rotoehu, were found to be homothermous throughout the year. Open water surface temperatures did not exceed 23°c in the North Island lakes or 19°c in the South Island, and minimum temperatures recorded were 7°c in the northern lakes and 5°c in the southern. In deep lakes the range of temperature was much less: Wakutipu had a range of 16–8.85°c. The disappearance level of a Secchi disc varied from 18 m (Lake Taupo) to 0.8 m (Lake Rotongaio). The transparency of the water in the glacial and volcanic lakes was comparable to that of similar lakes in other parts of the world. It was found that total ions, measured by the ion‐exchange resins reached high concentrations in lakes fed by thermal waters: Rotomahana 14.32m.e./l. By contrast Tikitapu, a seepage lake, had the low concentration of. 0.28m.e./l, and Wakatipu, a glacial fed lake, a concentration of O.58m.e./1. The pH range was 8.1–5.8, the lowest value being in Tikitapu, a volcanic lake. Slightly lower pH values were recorded in the bottom waters of lakes when stratified. Lakes were usually supersaturated with oxygen at the surface, and only a few small lakes showed a hypolimnial deficiency. Silica and phosphate were found in high concentrations in some thermal lakes but nitrogen in the forms measured, was found to be low.

Volcanic lakes originate from a volcanic crater or caldera, and were a crucial component of aquatic ecosystems. Sediment bacteria play an important role in the nutrient cycling of aquatic ecosystems; however, their patterns distribution in volcanic lakes and the surrounding river habitats are unknown. In this study, we compare the sediment bacterial communities and their co-occurrence networks between these two habitats in the Inner Mongolia Autonomous Region, Northeastern China (the Arxan UNESCO Global Geopark), using 16S rRNA gene amplicon sequencing. The results revealed that there were significant variations in the physicochemical parameters of the sediment between these two habitats. The bacterial α-diversity, β-diversity, and community composition of the sediment also significantly differed between these two habitats. Network analysis showed that the co-occurrence patterns and keystone taxa in the sediment differed between these two habitats. The sediment bacterial communities in the river habitats were more stable than those in the lake habitats in the face of environmental change. Canonical correspondence analysis demonstrated that both physical (pH and MC) and nutrition-related factors (TN, TP, LOI, and TOC) were the most important environmental factors shaping the variations of bacterial community composition (BCC) in the sediment between these two habitats. This work could greatly improve our understanding of the sediment BCC of the sediment from aquatic ecosystems in the UNESCO Global Geopark.

Volcanic lakes are ecosystems in which thermodynamic processes have a complex relationship with atmospheric variables. This study presents the results of an analysis of the thermal regime and dynamics of two high-altitude tropical lakes located in the crater of the Nevado de Toluca volcano in Mexico, at an altitude of more than 2200 m above sea level. Joint meteorological and hydrological measurements taken in two adjacent lakes revealed strong diurnal fluctuations in water temperature, which are caused by wind-induced internal gravity waves and free seiches oscillations. During the daytime, heating occurs in the near-surface layer of the lakes, which creates a thermocline at a depth of 2–3 m, but it is washed out at night. The heat penetration into the lakes is significantly different due to differences in water transparency and algae density, despite the small distance of only 200 m between the lakes separated by a 100-m high lava dome. Temperature and level fluctuations were analyzed using spectral analysis. The numerical model used in Lake El Sol allowed for the first-ever evaluation of the circulation and the impact of wind circulation regimes on lake-level fluctuations. Analyzing such physical processes is crucial in assessing the chemical and biological processes occurring in this reservoir. Field measurements uncovered unexpected temperature changes near the lake bottom, along with heat exchange between the bottom water layer and bottom sediments (during winter, sediments emit heat to the water column). The estimated heat fluxes through the lake bottom were less than 0.3 W/m2 during winter and less than 0.1 W/m2 for the rest of the year.

Thermal springs are ubiquitous features whose underground kinematic structure is mostly unknown but are typically thought to originate from deep sources. We documented a type of thermal springs at the banks of a volcanic lake that are discharge zones of hydrothermal convection cells circulating groundwater within the near shore environment. The convection captures lake water through the lakebed, mixes it with deeper groundwater at velocities of 100s of m d−1, then returns the water to the lake via the spring. The convection cell is flushed in a few hours and turns over the lake's volume in a few days. Most volcanic lakes and other relatively cool surface water bodies in areas of elevated geothermal heat fluxes meet the conditions for the occurrence of local hydrothermal circulation of groundwater. The type of spring we studied, the terrestrial version of black smokers, is likely present but perhaps unrecognized at many areas.

We investigated the volcanic Narlı Lake in Central Anatolia combining high-resolution bathymetry and geochemical measurements. In this study, we present it as proof of a new concept to verify fluid pathways beneath lakes integrating the structure of the geothermal reservoir into the surrounding tectonic frame. We recognized dextral faults fracturing inherited volcanic formations and thus generating highly permeable zones beneath the lake. At intersection points of faults, reservoir fluids discharge from deep holes as imaged by the high-resolution bathymetry at the bottom of the Narlı Lake. Onshore, the tectonic setting also generates both extensional and compressional structures. Extensional structures result in extensive fluid discharge through hot springs while compressional structures do not discharge any fluid. The water of the lake as well as in the hot springs is highly saline and has relatively high concentrations of Cl, HCO3, SO4, Na, Ca, Mg, and Si. In several hot springs, we observed mixtures of high-saline fluids having a deep origin and low-saline shallow groundwater. We observed discharge into the lake by gas bubbles, which contain probably CO2 or H2S. Mineral precipitation indicates a carbonatic source at the lake bottom and along the shoreline. Extensive travertine precipitation also occurs near hot springs along the nearby extensional zone of Ihlara Valley. In summary, the composition of fluids and minerals is controlled by water–rock interaction through the volcanic and carbonatic rocks beneath this volcanic lake.

We examined if precipitation had recovered from acidification in Guangzhou, the third biggest city in China, and if sulphur deposition in precipitation had decreased, and to what extent if yes, following abatement strategies in sulphur dioxide (SO2) emission and energy use implemented since 2001. SO2 emissions were decreasing steadily since 2001, but a marked recovery of precipitation acidity occurred only since 2005; precipitation pH values decreased from 4.65 in 2001 to 4.34 in 2005 and then increased to 5.08 in 2010, while in the same period acid rain (pH<5.6) frequency increased from 70% to 81% and then decreased to 48%. During this period, the change in pH value and sulphate concentration more reflected the patterns of SO2 emission at provincial and national scales than at the local scale, suggesting that precipitation chemical composition was largely controlled by the emissions of pollutants from surrounding areas of the study city. Since 2001, sulphate deposition in precipitation decreased significantly (by 40%) but nitrogen deposition remained unaltered. More importantly, the current sulphur (43 kg S ha−1 yr−1 as sulphate) and nitrogen depositions (35 kg N ha−1 yr−1 as ammonium plus nitrate in 2010) were still among the highest in China. These results highlight the fact that ambient sulphur and nitrogen deposition still pose a threat to the health of both terrestrial and aquatic ecosystems. Precipitation may become more acidified in the future because the deposition of alkaline dusts containing calcium is also likely to decrease with stricter SO2 emission control policy and reduced construction activities. Additionally, we recommend that a reduction of emissions of nitrogen and chlorine bearing pollutants is urgently required for complete control on acid deposition.

The exchange of free cholesterol of endogenous or exogenous origin between plasma and red blood cells has been studied. Using tritiated cholesterol and 14C-mevalonic acid or sodium-1-14C-acetate, it has been shown that after incubation of labeled plasma with control RBC or of labeled RBC with control plasma, the free cholesterol 3H/14C ratio in plasma or RBC is unchanged. This is true for incubation of 6 or 24 hr. In a parallel series of experiments it was observed that the plasma 3H/14C free cholesterol ratio was unchanged after 24 hr of incubation in the presence of native lecithin cholesterol acyl transferase. The data confirm the findings in man and baboon which suggest that it is not possible to distinguish between plasma free cholesterol of endogenous or exogenous origin.

Aim. To isolate and purify protein complexes – ATP synthase and RuBisCO – from pea leaf chloroplasts and study the effect of a microbiological fertilizer “Extracon” and sulfonamide inhibitors acetazolamide and ethoxyzolamide on the enzymatic activity of these proteins.Materials and methods. Chloroplasts were isolated from the leaves of two-week-old pea sprouts, protein complexes of purified thylakoid membranes were solubilized with digitonin (10 mg of digitonin per 1 mg of protein), the protein concentration was determined according to Lowry. Native electrophoresis with displacement of the charge of the soluble protein fraction from the chloroplast stroma, as well as membrane proteins, was carried out in the modified system of Anderson et al., Kolisnichenko et al. A modified Lemmley system was applied to the protein electrophoresis in the polyacrylamide gel in the presence of sodium dodecyl sulfate. The methods of Alain and Hintsik, as well as Gomorrah were used to determine the ATPase activity in the polyacrylamide gel. Visualization of the carbonic anhydrase activity in the polyacrylamide gel was performed by the method of Edwards and Petton. Results and discussion. Using physicochemical methods of potentiometry, spectrophotometry the ATPase, carbonic anhydrase and esterase activities of the enzymes were studied. The results obtained indicate that specific carbonic anhydrase inhibitors (acetazolamide and ethoxyzolamide) also block the esterase and ATPase activity of the enzyme complexes. “Extracon” (a multifunctional microbiological preparation) almost 1.5 times increases the activity of the enzymes, showing a complex activating effect of the fertilizer on both light and dark reactions of photosynthesis.Conclusions. The method of identification and isolation of RuBisCO and ATP synthase on the basis of two-dimensional electrophoresis and electrophoretic elution has been proposed. It allows determining the presence of certain enzyme activity of complexes at first in SDS plates (express analysis) and further to study the effect of various factors of endogenous and exogenous origin on the enzymatic properties of electrophoretically pure enzymes. The use of two-dimensional electrophoresis as a tool for assessing the impact of various factors of endogenous and exogenous origin on the plant cell and the plant as a whole through constant monitoring of the work and activity of enzyme systems of the plant cell is promising.