Recently there have been reports about large accumulations of algae on the beaches of Lake Baikal, the oldest and deepest freshwater body on earth, near major population centers and in areas with large concentrations of tourists and tourism infrastructure. To evaluate the observations indicating the ongoing process of eutrophication of Lake Baikal, a field study in July 2012 in the two largest bays of Lake Baikal, Barguzinsky and Chivyrkuisky, was organized. The study of phytoplankton using the sedimentary method and quantitative records of accumulations of macrophytes in the surf zone was made. In Chivyrkuisky Bay, we found the massive growth of colorless flagellates and cryptomonads as well as the aggregations ofElodea canadensisalong the sandy shoreline (up to 26 kg/m2). Barguzinsky Bay registered abundantly cyanobacterialAnabaenaspecies, cryptomonads, and extremely high biomass ofSpirogyraspecies (up to 70 kg/m3). The results show the presence of local but significant eutrophication of investigated bays. To prevent further extensions of this process in unique ecosystem of Lake Baikal, the detailed study and monitoring of the coastal zone, the identification of the sources of eutrophication, and the development of measures to reduce nutrient inputs in the waters are urgently needed.

Plankton sampling data from the period of 1951-2010 for Lake Baikal were used in this study. Data have been collected at least monthly, generally every 7-10 days, in depth profiles from the surface to 250 m at a single offshore sampling site in the southern basin, where the water depth is approximately 800 m. Measurements of abiotic variables and phytoplankton sampling were made at discrete water depths. The data for the top 50 m of the lake were averaged for temperature and biological characteristics, noting this is the water layer in the lake exhibiting most of the lake's photosynthetic production, as well as containing the most plankton organisms. Zooplankton samples were collected with a closing plankton net and enumerated at the species level and also identified by age class. Under-ice phytoplankton demonstrated the presence of some succession in spring phytoplankton, including a decreased proportion of endemic algal species. The openwater complex of the alga species demonstrated that some non-endemic species exhibited positive trends. The zooplankton analyses demonstrated a noticeable increasing trend for total zooplankton, the main zooplankton components being Epischura baicalensis, as well as increased Cladoceran numbers. These trends can be hypothetically explained by the following: (i) global climate change (although Lake Baikal also exhibits long-term temperature oscillations); (ii) regional warming (due to construction of reservoir systems during the 1950s-1970s period); (iii) local chemical pollution attributable to increased industrial and agricultural activity in the lake's watershed and airshed basins; and/or (iv) the natural oscillating behaviour of the lake's plankton components.

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Inadequate use of antibiotics has led to spread of microorganisms resistant to effective antimicrobial compounds for humans and animals. This study was aimed to isolate cultivable strains of actinobacteria associated with Baikal endemic alga Draparnaldioides baicalensis and estimate their antibiotic properties. During this study, we isolated both widespread and dominant strains related to the genus Streptomyces and representatives of the genera Saccharopolyspora, Nonomuraea, Rhodococcus, and Micromonospora. For the first time, actinobacteria belonging to the genera Nonomuraea and Saccharopolyspora were isolated from Baikal ecosystem. Also, it was the first time when actinobacteria of the genus Nonomuraea were isolated from freshwater algae. Some rare strains demonstrated activity inhibiting growth of bacteria and yeasts. Also, it has been shown that the strains associated with Baikal alga D. baicalensis are active against both Gram-positive and Gram-negative bacteria. According to this study and previously published materials, diversity of cultivable actinobacteria and rare strains isolated from D. baicalensis is comparable to that of cultivable actinobacteria previously isolated from plant sources of Lake Baikal. Also, it exceeds the cultivable actinobacteria diversity previously described for macroinvertebrates, water, or sediments of Lake Baikal. The large number of rare and active strains associated with the endemic alga D. baicalensis could be the promising sources for biopharmaceutical and biotechnological developments and discovery of new natural compounds.

Climate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends in full vertical thermal structure and deepwater temperatures, which have been changing less consistently in both direction and magnitude. Here, we present a globally-expansive data set of summertime in-situ vertical temperature profiles from 153 lakes, with one time series beginning as early as 1894. We also compiled lake geographic, morphometric, and water quality variables that can influence vertical thermal structure through a variety of potential mechanisms in these lakes. These long-term time series of vertical temperature profiles and corresponding lake characteristics serve as valuable data to help understand changes and drivers of lake thermal structure in a time of rapid global and ecological change.