Evaluation of the trophic level and self-cleaning ability of small flows by hydrochemical indicators (through the example of the Rpen River)

Aim. Assessment by nitrification index values of the level of trophicity and toxicity for aquatic organisms in the waters of a small watercourse in an urbanized area by the content of nutrients in the water and its selfcleaning ability.Materials and Methods. The concentration of compounds of nutrients in the waters of the river was determined using the "Kapel 104T." system of capillary electrophoresis. Water was sampled for analysis according to GOST R 51592- 2000. The water content of readily oxidized organic compounds was assessed by the magnitude of permanganate oxidizability (PND F 14.1; 2.4.154-99) and difficultly oxidized compounds by the magnitude of the chemical oxygen consumption (RD 52.24.421-2012). Assessment of the water trophic level was evaluated by measuring the content of various forms of mineral nitrogen and mineral phosphorus. The aggregation index characterizing the toxicity of various forms of mineral nitrogen to aquatic organisms was calculated by their ratio to MPC for fishery reservoirs. The nitrifying ability of river waters was estimated by the value of the nitrification index (Initr.), calculated by the ratio of the concentration of nitrogen of nitrates in water to the sum of the concentrations of various forms of mineral nitrogen and the self-cleaning ability by the values of the nitrification index.Results. In terms of the aggregation index, water at all sampling points was found to be toxic. The river ecosystem is characterized by a weak ability to cleanse itself and a weak nitrifying ability, which is associated with the influence of numerous cyanotoxins on the microbiocenosis of the watercourse and filtration organisms.Conclusion. It was shown that the most sensitive indicator of trophicity of river waters is the concentration of the mineral phosphorus. Through measuring the ratio of the concentrations of mineral nitrogen to mineral phosphorus, it was established that blue-green algae (cyanobacteria), producers of cyanotoxins, dominate in the phytoplankton of the river in all the points studied.

Effect of Projected Land Use and Climate Change on Water Quality of Old Woman Creek Watershed, Ohio

The separate and synergistic effects of land use and climate change on water quality variables in Old Woman Creek (OWC) watershed were evaluated using a hydrological model set up in Soil and Water Assessment Tool (SWAT) for the OWC watershed. Model calibration was done using a multi-objective evolutionary algorithm and pareto optimization. The Parameter-Elevation Regressions on Independent Slopes Model (PRISM) climate data and the 20 different Global Circulation Models (GCMs) developed by the Coupled Model Intercomparison Project Phase five (CMIP5) were used. Validation was done using the streamflow data from USGS gaging station and water quality data from the water quality lab, Heidelberg University. The simulation was divided into two land use scenarios: Scenario 1 for constant land use and Scenario 2 where land use was varied. Both land use simulations were run in four time periods to account for climate change: historical (1985–2014), current to near future (2018–2045), mid-century (2046–2075), and late-century (2076–2100) climate windows. For the historical period, the average of all the simulations made from the 20 different CMIP5 GCMs shows good agreement with the PRISM results for flow and the water quality variables of interest with smaller inter-model variability compared to PRISM results. For the other three climate windows, the results of Scenario 1 show an increase in flow and eight water quality variables (sediment (total suspended sediment), organic nitrogen, organic phosphorus (particulate p), mineral phosphorus (soluble reactive p), chlorophyll a, carbonaceous biochemical oxygen demand (CBOD), dissolved oxygen, total nitrogen) across the climate windows but a slight decrease in one water quality variable, mineral phosphorus in the mid-century. The results of Scenario 2 show a greater increase in flow, and the eight water quality variables across the climate windows show a relatively larger decrease in one water quality variable (mineral phosphorus). The projected land use change has little impact compared to the projected climate change on OWC watershed in the 21st century.

A Circular Economy for Phosphorus in Sweden—Is it Possible?

More sustainable management of phosphorus requires comprehensive understanding of phosphorus stocks and flows. With the purpose of shedding light on the possibilities for an increased level of recirculation of phosphorus in Sweden, phosphorus flows entering and exiting biomass production sectors were quantified along with waste flows, that is, flows that are not currently utilized in biomass production. Relevant waste flows were also characterized in terms of phosphorus concentration, plant availability, contamination and geo-spatial distribution. The theoretical recirculation potential of phosphorus in Sweden was then estimated. The results indicate that there is a large potential for making phosphorus management more circular, especially regarding the utilization of phosphorus in sewage sludge as well as wood ashes from the forestry sector. Moreover, there is a large amount of phosphorus in mining waste that could potentially be used for fertilizer production. It is concluded that the amount of phosphorus in flows fit for recirculation in forestry could more or less balance today’s output. In agriculture, however, recirculation can only sufficiently replace imported mineral phosphorus at current demand if the phosphorus in mining waste is utilized. Thus, if the goal is to replace all of the mineral phosphorus, the agricultural sector also has to become much more efficient in its phosphorus usage.

Hydroecological status of Kultuchnoe lake (Petropavlovsk-Kamchatskiy)

<p>Lake Kultuchnoe applies to lakes of lagoon type and is located in the historical center of Petropavlovsk-Kamchatsky. The area and volume of the lake in connection with human economic activity was repeatedly reduced during backfilling. In the early 90s of the last century the lake was divided into two parts. The area of the water mirror of both lakes is about 2 km<sup>2</sup>. The maximum depth of the Big lake – 7 m, Small lake– 1.2 m. Compared to the conditions that took place 30 years ago, there is an improvement in the state of the aquatic ecosystem and a decrease in the level of pollution. This is due to the reconstruction of urban sewage systems, in the 2000s, the release of fecal and industrial wastewater stopped. During the open water period a direct stratification is formed in the lake, and in the deepest part of it during the summer, low water temperatures remain in the bottom horizons and there is a lack of oxygen. The stratification is due to the insufficient length of wind acceleration for mixing the lake to the bottom and creates prerequisites for the formation of oxygen-free conditions below the boundary of the mixed layer (2-3 m). The systematic discharge of drainage wastewater into Lake Kultuchnoye through sewers with three outlets in the littoral part of the Big Lake and one in the Small Lake was revealed. According to the complex of components and indicators of water quality, the water in the Big and Small Lakes has a high level of, although the concentrations of many pollutants have decreased during the last 30 years. Compared to the state of the lake in 1990s, there was a decrease in the lake water of copper and manganese, phenols, petroleum products, ammonium nitrogen and BOD. Silty bottom sediments had a uniform composition, olive color. The content of organic matter reaches 14.4-16.9%, which indicates the active mineralization of organic residues. According to the content of mineral phosphorus (more than 10 μg/l), due to the influx of polluted waters, water masses do not experience a limit for the development of biota. In the Big Kultuchnoe Lake, the content of mineral phosphorus in the bottom horizons is 74-163 µg/l. In Small Kultuchnoe Lake, the content of mineral and total phosphorus is lower – up to 60 µg/l, which may be due to a more active process of its consumption by higher algae, which the lake is almost completely overgrown. Methane emission is the highest from the surface of the Small Lake (37.4 mgC / m<sup>2</sup>h), which is due to its high content in the water and low (up to 1 m) depth. For Big Kultuchnoe lake specific flow rate not exceeding 20,7 mgC/m<sup>2</sup>h. To preserve the ecosystem of the lake, which is located in the historical part of the city near important tourist infrastructure and has great recreational value, it is proposed to create phyto-treatment facilities that would intercept drainage runoff and not violate the overall appearance of the landscape.</p>

Mineral phosphorus drives glacier algal blooms on the Greenland Ice Sheet

Melting of the Greenland Ice Sheet is a leading cause of land-ice mass loss and cryosphere-attributed sea level rise. Blooms of pigmented glacier ice algae lower ice albedo and accelerate surface melting in the ice sheet’s southwest sector. Although glacier ice algae cause up to 13% of the surface melting in this region, the controls on bloom development remain poorly understood. Here we show a direct link between mineral phosphorus in surface ice and glacier ice algae biomass through the quantification of solid and fluid phase phosphorus reservoirs in surface habitats across the southwest ablation zone of the ice sheet. We demonstrate that nutrients from mineral dust likely drive glacier ice algal growth, and thereby identify mineral dust as a secondary control on ice sheet melting.

Immunomodulatory Effects of Dietary Phosphorus and Calcium in Two Strains of Laying Hens

Insufficient nutrient supply can impair the immune system, which is important for animal health and welfare. Since chicken can partly hydrolyze phytate, which is the primary phosphorus storage in plant seeds, a reduction of mineral phosphorus in the diets could be an option for more sustainable egg production. Laying hens require high concentrations of calcium that might inhibit the function of endogenous enzymes for phytate hydrolyzation. The objective of this study was to characterize the impact of standard and reduced dietary phosphorus and calcium concentrations on the number and functionality of immune cells in the peripheral and gut-associated immune system in a white and brown laying hen strain. Reduced mineral phosphorus enhanced several immune parameters such as B cells in blood and IgA concentrations in bile in both strains, and peripheral monocytes and T cells in cecal tonsils in brown hens. Reduced calcium levels resulted in lower numbers of T cells in blood and cecal tonsils in both strains, suggesting negative effects on adaptive immunity. Differences between the two strains were found in almost all immune parameters. Results suggest a potentially beneficial effect of reduced dietary mineral phosphorus on the immune system that is dependent on the genetic background.