Experimental studies to increase the natural resources of brine shrimp Artemia in hyperhaline reservoirs

A brief analysis of the available technologies for growing Artemia in the world and in Russia is given in the paper. The conditions for production of Artemia in natural reservoirs with a local Artemia population are shown. The results of laboratory experiments on reducing the incubation time of cysts to 2-23 hours (instead of the standard 24-48 hours) and the inoculation of nauplii and non-hatched cysts into the brine of natural lakes with salinity of 101, 125, 225 and 333‰ are given in details. The following indicators are analyzed: the rate of hatching during incubation, the rate of hydration of cysts during incubation and dehydration in brine; the survival rate of nauplii in brine, the possibility of hatching nauplii from cysts in brine with different salinity. The results of long-term observations of the survival of Artemia crustaceans in the brine of the lake in the absence of feeding are also presented. It is possible to reduce the incubation time to 6-20 hours is concluded in the paper. The dependence of the duration of incubation of cysts on the temperature, quality of cysts and salinity of natural brine was noted. To determine the optimal incubation time of cysts the formulas for calculating T90 according to the temperature and salinity of brine for cysts of different quality are given.

Studies on Algae from the Order Synurales (Chrysophyceae) in Northern Vietnam

The present paper focuses on the flora of synuralean algae from four northern provinces in Vietnam: Bac Kan, Hanoi, Ninh Binh, and Thanh Hoa. Fifty-five water bodies were studied, including territories within national parks Ba Be, Ba Vi, Cuc Phuong, Ben En, and Trang An Wetland—The World Cultural and Natural Heritage and Van Long Wetland Nature Reserve. Samples were obtained from natural lakes and wetlands, artificial reservoirs and ponds, and small temporary water bodies. Electron microscopy allowed for the discovery of 39 taxa, 37 of which belonged to the genus Mallomonas and two to the genus Synura. Six taxa of the genus Mallomonas and two taxa from the genus Synura were not identified to the lower rank. Five taxa are reported for the first time in Vietnam. The most diverse flora was observed in natural protected water bodies. Eutrophic and hypereutrophic water bodies, which were prevalent in the study area, had a reduced number of selected species.

Plant species diversity of the wet meadows under natural and anthropogenic interventions: The case of the Lakes Amvrakia and Ozeros (W. Greece)

The Lakes Amvrakia and Ozeros (W. Greece) belong to the western chain of Greek wetlands running along the coast of the Ionian Sea. They are both natural lakes belonging to the Natura 2000, Site of Community Importance (pSCI) and are characterized by high ecological value. Wet meadows are typical habitat types of these wetland ecosystems which are in contact with rural ecosystems which they interact with. Due to the high conservation value of these habitat types, in the framework of this study the flora of the wet meadows was recorded and a floristic analysis concerning chorology, life forms and habitat preferences was made. A total number of 152 taxa was found in the wet meadows of both lakes from which only 47 taxa were common. The families with the greatest number of species were Fabaceae (22 taxa), Asteraceae (14 taxa) and Poaceae (9 taxa) for the wet meadow vegetation of the Lake Amvrakia and Fabaceae, Poaceae (17 and 13 taxa, respectively) for the Lake Ozeros. In both lakes the prevalence of the Therophytes is evident, while the life forms of Chamephytes and Aquatics were absent from the Lake Amvrakia. From the results of the canonical correspondence analysis among species, sampling plots and selected environmental variables, a clear separation between species and sampling plots was found, presenting strong correlation with specific edaphic parameters (pH, CaCO3, EC, , Total N, SOC and ). These edaphic properties, as a result of natural and anthropogenic interventions, seem to play an important role in the wet meadows plant species distribution pattern.

Evaluating Primary Productivity Based on Chlorophyll-a in Ciburuy Lake, West Java Indonesia

Ciburuy Lake is the one of many natural lakes in Padalarang, West Java. Padalarang is industries area and pruduce huge waste water to contamination Ciburuy Lake. Ciburuy Lake area has many functions such as tourism, settlement, agriculture and industry. This study aim to evaluate velue of primary productivity based on chlrophyill-a. Chlorophyll-a is one of the indicator to creat management plan of water resources in Ciburuy Lake. This research was conducted from January to March 2021. Sampling carried out in 4 station with deferent water situation. This research used chlorophyll-a concentration measurment method to determine primary productivity. Result obtained in terms of water quality are: temperature range of 24 - 28 oC; depth water range of 151,83 – 190,83 cm; Transparation range of 22,83 – 27,67 cm; pH range of 5,94 – 8,00; CO2 range of 6,98 – 33,52 mg/L; BOD range of 7,84 – 12,14 mg/L; nitrate range of 0,235 – 0,312 mg/L; fosfate range of 0,142 --0,156 mg/L, and chlorophyll-a concentration range of 0.024 - 0.065 mg/L . This research showed that Ciburuy Lake has water condition eutrophic to hypertrophic because primary productivity in Ciburuy Lake has middle to high condition based on chlorophyll-a concentration.

Long-Term Changes in Floristic Diversity as an Effect of Transforming the Lake into a Retention Reservoir

The Łęczna-Włodawa Lake District is one of the most valuable natural regions in Europe. It is an area of numerous lakes, peat bogs, swamps and forests, which has been undergoing intensive transformation for decades. Among the largest projects were the creation of the Wieprz Krzna Canal system along with the drainage system and the transformation of natural lakes into retention reservoirs. Among the transformed lakes is Lake Wytyckie. The land was used for analyses near the lake, and floristic and habitat analyses were carried out within the boundaries of the contemporary embankment. The studies were carried out from the 1950s, when the lake functioned as a natural reservoir, through to the 1980s (the transformation of the lake), to the 2020s. Lake Wytyckie was transformed into a retention reservoir by increasing its size and flooding the areas inhabited mainly by peat bog, meadow and forest vegetation, which contributed to the impoverishment of both species and habitat diversity of the area, while it increased the nutrient richness of the water. This was reflected both in the decline in the value of individual diversity indices as well as in the ecological index numbers. In the first period of the research, the area was dominated by wetlands, not drained, with a large variety of species that preferred good lighting conditions. Additionally, the habitat was characterized by low reaction, temperature and trophic values. In the following period, there was an increase in the depth of the water of the reservoir, characterized by high water visibility values, which contributed to the presence of protected species, as did the low moisture content of the areas within the embankment and a neutral pH. The factors currently influencing the formation of the vegetation structure are the high humidity of the entire embankment area, the increase in pH, and the significant increase in the share of built-up areas in the immediate vicinity.

Bacterial Community Spacing Is Mainly Shaped by Unique Species in the Subalpine Natural Lakes of China

Bacterial communities have been described as early indicators of both regional and global climatic change and play a critical role in the global biogeochemical cycle. Exploring the mechanisms that determine the diversity patterns of bacterial communities and how they share different habitats along environmental gradients are, therefore, a central theme in microbial ecology research. We characterized the diversity patterns of bacterial communities in Pipahai Lake (PPH), Mayinghai Lake (MYH), and Gonghai Lake (GH), three subalpine natural lakes in Ningwu County, Shanxi, China, and analyzed the distribution of their shared and unique taxa (indicator species). Results showed that the species composition and structure of bacterial communities were significantly different among the three lakes. Both the structure of the entire bacterial community and the unique taxa were significantly influenced by the carbon content (TOC and IC) and space distance; however, the structure of the shared taxa was affected by conductivity (EC), pH, and salinity. The structure of the entire bacterial community and unique taxa were mainly affected by the same factors, suggesting that unique taxa may be important in maintaining the spatial distribution diversity of bacterial communities in subalpine natural freshwater lakes. Our results provide new insights into the diversity maintenance patterns of the bacterial communities in subalpine lakes, and suggest dispersal limitation on bacterial communities between adjacent lakes, even in a small local area. We revealed the importance of unique taxa in maintaining bacterial community structure, and our results are important in understanding how bacterial communities in subalpine lakes respond to environmental change in local habitats.

Mercury Export From Freshwater to Estuary: Carbocentric Science Elucidates the Fate of a Toxic Compound in Aquatic Boreal Environments

The chemistry of mercury in freshwater systems, particularly man-made reservoirs, has received a great deal of attention owing to the high toxicity of the most common organic form, methylmercury. Although methylmercury bioaccumulation in reservoirs and natural lakes has been extensively studied at all latitudes, the fate of the different forms of mercury (total vs. dissolved; organic vs. inorganic) along the entire river-estuary continuum is less well documented. In fact, the difficulty of integrating the numerous parameters involved in mercury speciation in such large study areas, combined with the technical difficulties in sampling and analyzing mercury, have undoubtedly hindered advances in the field. At the same time, carbocentric science has grown exponentially in the last 25 years, and the common fate of carbon and mercury in freshwater has become increasingly clear with time. This literature review, by presenting the knowledge acquired in these two fields, aims to better understand the extent of mercury export from boreal inland waters to estuaries and to investigate the possible downstream ecotoxicological impact of reservoir creation on mercury bioavailability to estuarine food webs and local communities.

Uzbekistan’s Aquatic Environment and Water Management as an Area of Interest for Hydrology and Thematic Tourism

The functioning of Uzbekistan’s economy is closely linked to the water resources of its huge cross-border rivers: the Amu Darya and the Syr Darya, as well as to the groundwater present within their basins. Both natural lakes and artificial reservoirs (e.g. the Aydar-Arnasay system of lakes, the Kayrakkum Reservoir, the Chardarya Reservoir) are present there, which retain significant amounts of water, and large canals with lengths of up to several hundred kilometres which involve complex hydraulic structures are used for irrigation purposes. All these are components of a water management system which needs optimisation; as much as 80% of agricultural land is irrigated, with 70% of the water being lost due to inefficient irrigation systems. The consequence of this allocation of river flows and the overuse of water in irrigation systems has been the disappearance of the Aral Sea (1960 year – 68,900 km2, 2017 year – 8,600 km2) and the inflow of water into the Sarygamysh Lake as well as the reduction of Uzbekistan’s groundwater resources by about 40%. The intensive development of irrigated agriculture is associated with changes in surface and groundwater quality caused, inter alia, by the increased use of chemicals in agriculture and the discharge of collector-drainage waters into river systems as well as their reuse. The extent of environmental degradation in some areas (especially in the Aral Sea region) is unique on a global scale. The origins of Uzbekistan’s other hydrological tourist attractions are related to attempts to ensure the availability of water for both human consumption and industrial use under conditions of water scarcity in the country’s arid and semi-arid climates. Not just the spectacular watercourses and water bodies present there (e.g. rivers, lakes, canals), but also small water retention facilities and minor infrastructure elements (e.g. wells, springs and retention basins, canals, ditches and flow control structures) are of potential tourist importance.

Attitudes of Young People Towards Lakes as a Premise for Their Public Participation in Environmental Management

Lake protection is a very important element of environmental management. This is especially true of lake districts, where the lakes are an important resting place for residents, especially young people. The crucial is the question whether young people who participate in lake management in the future, are ready for it. It was assumed that their attitude towards lakes would be an indicator of such preparation. This study aimed to define a set of respondents’ features that may condition the specific model of participation. Based on the research conducted among young residents (N = 167) of the Szczecinecki District in Poland, it was found that their pro-environmental attitudes were dominated by high values of the traits that make up the emotional component, average values of the cognitive component and the lowest values of activity. The lower the score of the overall attitude, the more often the respondents chose Recreational Lakes, rather than General Development or Natural Lakes. The most important feature that may determine the level of participation in the future is readiness to act. A comprehensive attitude index was created, which shows that it is worth examining the characteristics of respondents that correlate with the willingness to act, i.e., knowledge, logical thinking, creativity and belief in the effectiveness of actions taken and attachment to the place of residence, when planning participatory management in lakeland areas.