Influence of water motion on the spatial distribution of Spirogyra in Lake Baikal

We investigated the diversity of benthic algal communities as well as phytoplankton in Lake Baikal. The structure of benthic algal communities changed in comparison to the period before 2000 due to intense development of filamentous algae, particularly Spirogyra. Percent cover of filamentous algae in different areas of the coastal zone varied from 0 to 100%. The lowest Spirogyra biomass was recorded in the surf and wave-breaking zones, whereas the highest biomass was observed in the area of the bottom less affected by waves. Fragments of Spirogyra thallomes were also recorded in the phytoplankton community of Lake Baikal's southern basin which is a new phenomena not previously recorded in the lake. Hydraulic characteristics of Spirogyra were similar to those of planktonic diatoms. Currents and wave effects on the bottom favored transfer and distribution of Spirogyra from locations with intense development to the coastal area of Lake Baikal. Spirogyra is now found throughout Lake Baikal.     

Major biomass fluctuations in lake food webs – An example in the peri-alpine Lake Annecy

In aquatic ecosystems, young of the year (YOY) fish often exhibit strong interannual fluctuations. Because these fish prey on zooplankton and are preyed upon by piscivorous fish, strong fluctuations in their abundance may have important impacts on food web functioning. The static Ecopath model was used to assess potential impacts of strong fluctuations in YOY perch in the deep peri-alpine Lake Annecy. We modeled two contrasting years in terms of YOY perch biomass: a situation with a high biomass of YOY perch and a situation with a low biomass of YOY perch. Additionally, five models were derived from the two initial models to better explore the effects of YOY perch biomass fluctuations on food web functioning. Disparities were revealed in terms of the activity of the system (volume of flows) and the trophic transfer efficiency. When the YOY perch biomass was high, the volume of flows within the system was less important, but the trophic transfers were more efficient than when the biomass was low. The high biomass of YOY perch appeared to facilitate transfers from low to high trophic levels. The results indicated that strong variabilities in the abundance of YOY fish had little impact on the main food web flows and pathways because of the capacity of predators to feed on various prey (omnivory) but could induce significant differences in food web properties (e.g. ascendancy, robustness) and organization (e.g. cycling, mean trophic level).     

Toxic and essential metals in Cyprinus carpio,Carassius gibelio,and Luciobarbus esocinus tissues from Keban Dam Lake,Pertek, Turkey

In various tissues of Luciobarbus esocinus, Cyprinus carpio, and Carassius gibelio which were taken from Keban Dam Lake Pertek region’s freshwaters, Turkey in January–February 2016, concentrations of mercury, nickel, lead, cadmium, arsenic, manganese, chromium, and cobalt were analysed by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. In fish muscle mean chromium concentration (0.614 mg kg^?1 in C. carpio muscle) was higher than the maximum limits as set by the Federal Environmental Protection Agency and World Health Organisation. Additionally, mean concentration of lead (0.380 mg kg^?1 in C. gibelio muscle) was higher compared to the maximum limit as set by Turkish Standards. Furthermore, in the assessment of the potential health risk, estimated weekly and daily intake of all metals were considerably below permissible tolerable weekly intake (PTWI) and permissible tolerable daily intake values. As a result, consumption of these fish species from this region does not pose a problem on human health.     

Ecology and timing of black bass spawning in Lake Ontario and the St. Lawrence River: Potential interactions with the angling season

The timing of spawning for largemouth bass and smallmouth bass in Lake Ontario and the St. Lawrence River was examined over a 3-year period. Temperatures were warmer in the preferred spawning habitat of largemouth bass, and the majority of nests had offspring that had reached the swim-up stage at the opening of the bass angling season in 2 of the 3 years examined. In contrast, the proportion of smallmouth bass nests that had reached the swim-up stage when the bass angling season opened ranged from 4 to 13% during these years. Using models created from nest observations and temperature data, we provide estimates of the additional time required to allow higher percentages (20%, 50% and 80%) of smallmouth bass nests to reach the swim-up stage. Invasive round goby, which are an important nest predator, were more abundant in the spawning habitat preferred by smallmouth bass. A simulated angling experiment showed that round gobies invaded about half of the nests when the guarding male was briefly angled and released. In view of these results, it may be important to re-evaluate the dates for the closed season in order to maintain the quality of the bass fisheries in Lake Ontario and the St. Lawrence River.     

A three-dimensional hydro-geochemical model to assess lake acidification risk

Biogeochemical and hydrological fluxes from riparian zones to lake environments can be significant, particularly for shallow systems experiencing large variations in water level, yet they are not considered in water quality models. To address this challenge we dynamically coupled a three-dimensional surface water model with a soil hydro-geochemical model of the riparian zone and used the coupled system to simulate the impacts of acid sulfate soils on the water quality of a morphologically complex coastal lake system in South Australia. A 3-yr simulation was undertaken to capture a period of exposure and re-flooding of pyrite-bearing sediments and acid fluxes to the lake. Model performance was assessed against data from several acidification events that occurred and the simulations reproduced the observed spatio-temporal variation in the expression of soil and water acidity. The model approach introduced here has potential for simulating systems where the terrestrial–aquatic linkage is important in shaping water quality.     

The effectiveness of small-to-medium river basin organizations in China: a case study of the Erhai Lake Basin Management Commission

Drawing on empirical evidence from a case study conducted in the upper Mekong catchment, this article assesses the performance of the Erhai Lake Basin Management Commission, an organization mandated to control pollution and integrate the diverse interests of those individuals and communities living and working near Erhai Lake. Clear local rules, strong enforcement, practical protocols, clear responsibilities and extensive mobilization have been crucial to the success of this small river basin organization. However, the insufficient involvement of numerous important stakeholders in decision-making processes has decreased the commission’s capacity to address water issues.     

Restoration of Polders Through Nature-Based Solutions—Landscape Practice in the Start-up Area of Jianyang Lake Wetland Park

The historical fisheries and the speedy urban development have dramatically threatened the ecological resources of Jianyang Lake in Zhejiang Province—the original texture of the site was largely damaged, the lake was severely polluted, and the Ardeidae habitats were badly degraded. To improve the water quality and restore the habitats of Jianyang Lake, as well as represent the scenery of groups of Ardeidae inhabiting there, the design team restored existing polder wetlands through NatureBased Solutions and set up a 16 hm² Start-up Area of the Jianyang Lake Wetland Park. Applying the proposed design concept of “Retaining-Breaking-Integrating,” an integrated ecosystem composed of forest, pond, farmland, lake, and island was formed. The design team also introduced a high-efficiency wetland purification system which is harmoniously embedded with the local image and resilient to climate changes with low maintenance, facilitating the optimization of the Ardeidae habitats. The long-term monitoring and maintenance would ensure the efficiency of the wetland purification system and spontaneous succession of the plant communities. The design concept, construction process, and performance of the Start-up Area can further offer references to restoration of the other parts of the park.     

Long‐term impacts from damming and water level manipulation on flow and salinity regimes in Lake Urmia,Iran

Lake Urmia in the north‐west of Iran is very large, very shallow and several times more saline than ocean water. The salinity of this terminal lake is of great ecological consequence for the existence and growth of Artemia Urmiana, a unique zooplankton endemic to the lake. It is a main food source for large bird populations. During the past decades, Lake Urmia has been strained by a number of anthropogenic and natural causes. They include extensive damming on the contributory rivers, building a dike‐type causeway and climate change. This paper deals with the long‐term impacts of damming, fresh water overexploitation and water level manipulation on flow and salinity conditions in Lake Urmia. For this purpose, the flow and salinity regimes were numerically simulated for the next four decades. The validity of the pseudo‐three‐dimensional hydrodynamic and advection‐dispersion models was assessed through sensitivity analysis of the models and comparing the simulated results against field measurements. The model predicted that because of damming on the rivers, the mean water level in the lake will possibly experience a drop of 2.2–2.8 m over next 40 years. The results indicated that, over decadal time periods, the lake most probably will be split into two interconnected smaller lakes. The northern lake was foreseen to become extremely saline, which will seriously threaten the Artemia's survival in this area. Over the long‐term periods, the southern lake seemed not to deviate much from its existing conditions. It however appeared to become more responsive to seasonal climatic changes and to the rivers inflow, as compared with its current conditions. Effects from climate changes were not considered in the current study.     

一株高产类胡萝卜素光合细菌Zl的研究

自高原湖泊阳宗海中分离得到一株类胡萝卜素高产光合细菌，命名为Zl。在优化的培养基中添加10ppmFe^3 及180ppmMg^2 ，于30℃，光照为1000lux，厌氧的最适条件下培养4天后，类胡萝卜素的产量可达50．2mg／g。对该色素制品进行一系列性质研究后表明，该色素溶液对光照、温度、酸碱的耐受性较好；对真核生物有良好的紫外线防护作用，在培养基中其含量为1mg／L时，保护率已超过60％。对这些性质的研究为开发和利用光合细菌天然色素提供一定依据。     

太空酒曲中功能菌的生物酶活性研究

从太空酒曲中分离、选育出主要功能菌：根霉SKR3、黑曲霉SKA2、米曲霉SKO3；与原生产中使用的曲药的主要功能菌-根霉SNR1、黑曲霉SNA4、米曲霉SNO2的酶活性进行比较研究。结果表明：SKR3的糖化酶、液化酶活性均比SNR1高出两倍以上，SKR3培养36h后其糖化酶、液化酶活性达到SNR1培养72h后的两倍；SKA2的糖化酶、液化酶活性比SNA4的高出三倍，蛋白酶活性高出一至二倍，SKA2培养48h后糖化酶、液化酶活性达到SNA4培养72h的三倍；SKO3与SNO1的糖化酶、液化酶、蛋白酶活性基本无差异。