Pond Area Research Articles

Экологическая оценка качества воды Большого Садового пруда на территории Тимирязевской академии в Москве

The paper presents the results of the assessment of water quality in a Large Garden pond, which is located in the Timiryazevsky district of the Northern Administrative District of Moscow, on the territory of the park RGAU-MSHA named after K. A. Timiryazev. Oxygen dissolved in water, temperature, hydrogen index (pH) and the content of iron, copper, chlorides, nitrites and ammonium nitrogen were measured in the studied reservoir in winter and summer 2020 according to a single sampling and analysis scheme. Water sampling for analysis was carried out in accordance with GOST 51592-2000 "Water. General requirements for sampling" at 7 points distributed along the horizontal and vertical axes of the pond, at three levels (on the surface, in the middle of the water column and at the bottom). Determination of chemical indicators of water quality was carried out on the day of water sampling by photometric method, on the spectrophotometer "PC spectro Lovibond". Studies have shown a significant spatial variation of most of the studied indicators both in the pond area and in the depth of the reservoir, reaching multiple differences in the case of ammonium content and pronounced in the content of chlorides, iron and copper. On average, an almost twofold increase in the chloride content in winter indicates a significant impact on the water quality in the pond of the use of anti-icing reagents in the adjacent territory. The copper content increases significantly in the summer, with the highest values in the dam part of the pond with the maximum level of technogenic load. The lowest content of pollutants is observed in the upper part of the pond with minimal anthropogenic load. The negative impact of the roadway of Pryanishnikov Street is much more pronounced than the intense recreational load in the beach area. The anthropogenic alkalinization of the environment characteristic of Moscow is less evident in the central part of the pond with maximum depths. The dissolved oxygen content is closely related to the temperature of the water and the depth of its sampling. In summer, it is more at the bottom than at the surface of the pond. In winter, samples taken in the surface horizons of the reservoir are characterized by a lower temperature and are more saturated with oxygen than water samples taken at depth. The results obtained show the importance of the depth and area of the pond mirror for preserving the quality of its water in Moscow. Anthropogenic water pollution, which does not reach the maximum permissible concentrations, but is pronounced even in the conditions of one of the most environmentally friendly areas of the city, is actualized by the task of further reducing the regulated level of man-made load on the territories adjacent to urban reservoirs. The increased spatial variation of water quality and the patterns of its changes in the water area and depth of the reservoir noted in the work should be taken into account when planning and evaluating the results of monitoring and reclamation measures. Keywords: WATER QUALITY, AQUATIC ECOSYSTEMS, HYDROCHEMICAL PARAMETERS, TEMPERATURE, CHEMICAL ELEMENTS, DISSOLVED OXYGEN

Ignoring carbon emissions from thermokarst ponds results in overestimation of tundra net carbon uptake

Abstract. Arctic permafrost landscapes have functioned as a global carbon sink for millennia. These landscapes are very heterogeneous, and the omnipresent water bodies within them act as a carbon source. Yet, few studies have focused on the impact of these water bodies on the landscape carbon budget. We deepen our understanding of carbon emissions from thermokarst ponds and constrain their impact by comparing carbon dioxide and methane fluxes from these ponds to fluxes from the surrounding tundra. We use eddy covariance measurements from a tower located at the border between a large pond and semi-terrestrial tundra. When we take the open-water areas of thermokarst ponds into account, our results show that the estimated summer carbon uptake of the polygonal tundra is 11 % lower. Further, the data show that open-water methane emissions are of a similar magnitude to polygonal tundra emissions. However, some parts of the pond's shoreline exhibit much higher emissions. This finding underlines the high spatial variability in methane emissions. We conclude that gas fluxes from thermokarst ponds can contribute significantly to the carbon budget of Arctic tundra landscapes. Consequently, changes in the water body distribution of tundra landscapes due to permafrost degradation may substantially impact the overall carbon budget of the Arctic.

Comparison of Three Water Indices for Tropical Aquaculture Ponds Extraction using Google Earth Engine

Information on the spatial distribution of aquaculture ponds, especially the inland brackish aquaculture, is crucial for effective and sustainable aquaculture management. Google Earth Engine (GEE) has been utilized to quickly map aquaculture ponds in different parts of the world, but the application is still limited in tropical regions. Selection of an optimal water index is essential to accurately map the aquaculture ponds from the Landsat 8 satellite images that are available in GEE. This study aims to evaluate the capability of three different water indices, namely Normalized Difference Water Index (NDWI), Modified Normalized Difference Water Index (MNDWI) and Automated Water Extraction Index (AWEI), in mapping of the aquaculture ponds in Sungai Udang, Pulau Pinang, Malaysia. The results show that MNDWI is the best index for aquaculture ponds extraction in Sungai Udang, with an accuracy of 81.87% and Kappa coefficient of 0.61. Meanwhile, the accuracy of NDWI and AWEI as compared to the digitized aquaculture ponds are 58.21 and 61.60%, and Kappa coefficient of 0.33 and 0.36, respectively. Then, MNDWI was applied to calculate the spatial changes of aquaculture ponds from 2014 to 2020. The result indicates that the area of aquaculture ponds has expanded by 26.16% since the past seven years.

Identifying Urban Wetlands through Remote Sensing Scene Classification Using Deep Learning: A Case Study of Shenzhen, China

Urban wetlands provide cities with unique and valuable ecosystem services but are under great degradation pressure. Correctly identifying urban wetlands from remote sensing images is fundamental for developing appropriate management and protection plans. To overcome the semantic limitations of traditional pixel-level urban wetland classification techniques, we proposed an urban wetland identification framework based on an advanced scene-level classification scheme. First, the Sentinel-2 high-resolution multispectral image of Shenzhen was segmented into 320 m × 320 m square patches to generate sample datasets for classification. Next, twelve typical convolutional neural network (CNN) models were transformed for the comparison experiments. Finally, the model with the best performance was used to classify the wetland scenes in Shenzhen, and pattern and composition analyses were also implemented in the classification results. We found that the DenseNet121 model performed best in classifying urban wetland scenes, with overall accuracy (OA) and kappa values reaching 0.89 and 0.86, respectively. The analysis results revealed that the wetland scene in Shenzhen is generally balanced in the east–west direction. Among the wetland scenes, coastal open waters accounted for a relatively high proportion and showed an obvious southward pattern. The remaining swamp, marsh, tidal flat, and pond areas were scattered, accounting for only 4.64% of the total area of Shenzhen. For scattered and dynamic urban wetlands, we are the first to achieve scene-level classification with satisfactory results, thus providing a clearer and easier-to-understand reference for management and protection, which is of great significance for promoting harmony between humanity and ecosystems in cities.

Characteristics and spatiotemporal distribution of microplastics in sediments from a typical mariculture pond area in Qingduizi Bay, North Yellow Sea, China

Microplastics (MPs) in mariculture environments may have an impact on mariculture and ecosystems. This study sampled the sediments in mariculture ponds and offshore areas in Qingduizi Bay during winter and summer. The abundance, characteristics, spatiotemporal distribution and pollution risk of microplastics were analyzed. The results showed that the abundance of MPs in the mariculture pond and offshore area was 49.2 ± 35.9 items·kg−1 d.w. and 17.1 ± 9.9 items·kg−1 d.w.; the MPs were mainly composed of transparent fibers of thickness 2000–5000 μm, with the main polymers being polyethylene terephthalate (PET) and cellophane (CP). The spatial distribution showed a downward trend from the inside to the outside, but the difference was not significant when comparing different seasons. The pollution load index (PLI) risk assessment showed that all sampling sites were at Hazard Level I. This study can provide valuable information for the risk assessment of microplastic pollution in mariculture areas.

Mass removal efficiencies in water and consequences after a river diversion into coastal wetlands: second thoughts

Salinity control, nutrient additions, and sediment supply were directly or indirectly the rationale for a $220 million coastal wetland restoration project (Davis Pond River Diversion) that began in 2002. We sampled Mississippi River water going in and out of the receiving basin from 1999 to 2018 to understand why wetland loss increased after it began. There was a reduction in inorganic sediments, nitrogen (N), and phosphorus (P) concentrations within the ponding area of 77%, 39% and 34%, respectively, which is similar to that in other wetlands. But the average sediment accumulation of 0.6 mm year−1 inadequately balances the present-day 5.6 mm year−1 sea level rise or the 7.9 ± 0.13 mm year−1 accretion rates in these organic soils. Nutrients added likely reduced live belowground biomass and soil strength, and increased decomposition of the organic matter necessary to sustain elevations. The eutrophication of the downstream aquatic system from the diversion, principally by P additions, increased Chl a concentrations to a category of ‘poor’ water quality. We conclude that this diversion, if continued, will be a negative influence on wetland area and will eutrophy the estuary. It is a case history example for understanding the potential effects arising from proposed river diversions.

Community structure of dragonfly (insecta: Odonata) in pond habitat at Sumur Panguripan Cultural Reserve, Surabaya, Indonesia

The Sumur Penguripan Cultural Reserve is an area of clean water wells in which there are two types of ponds, namely Canopied and Non-Canopied, with unspoiled environmental conditions. So, this area has potential as a natural habitat for the dragonfly community. The community of dragonflies at a location can be an environmental indicator, especially in waters, and also be used as a biological control for the terrestrial environment. This study aimed to report differences in the dragonfly’s structure community from the two types of canopy in the pond area of the Sumur Panguripan Cultural Reserve. This study uses the Visual Encounter Survey (VES) method was modified using the Belt Transect method. The results of a study conducted in this location found that there were 20 species from 4 families, with 294 individuals. The value of species diversity of dragonflies at non-canopied locations is H’= 2.26, highest than the value of species diversity of dragonflies at locations with canopied that is H’= 1.87. At the canopied pond location, there were eight species with 48 individuals from 3 families. Meanwhile, at the Non-canopied pond location, there were 18 species with 246 individuals from 3 families.

An in-pond tank culture system for high-intensive fish production: Effect of stocking density on growth of grass carp (Ctenopharyngodon idella Valenciennes, 1844) and blunt snout bream(Megalobrama amblycephala Yih, 1955)

Pond partitioned aquaculture system is developed in recent years, and it contributes to increasing yield and lowering land occupation. Based on the concept of partitioned aquaculture system, a new in-pond tank culture system (IPTCS) was constructed in this study. This system consists of culture tank, capture and aeration module, waste collection module, and vertical flow constructed wetland (VFCW), and the effective rearing area takes up about 10.05% of the pond area. In IPTCS, grass carp ( Ctenopharyngodon idella Valenciennes, 1844) and blunt snout bream ( Megalobrama amblycephala Yih, 1955) were reared at high and low stocking densities for 120 days. The initial density of grass carp in the high and low density groups was 15 kg m −3 and 7.5 kg m −3 , respectively, and that of blunt snout bream were 10 kg m −3 and 5 kg m −3 . During the experiment, the aeration module worked 6 h / day, and the waste collection module worked 5 min / day. The results showed that high stocking density had a negative impact on the growth performance and muscle quality of grass carp and blunt snout bream, and that the water quality in the culture tank gradually was deteriorated with the increasing stocking density. The economic benefits of different stocking densities in this system were investigated in this study, and grass carp high-density rearing failed to generate high benefits, but blunt snout bream high-density rearing leads to a higher income. The feasibility and rearing effect of the in-pond culture tank system were preliminarily confirmed. • A new type of in-pond tank culture system (IPTCS) was constructed. • The economic benefit of theIPTCS was analyzed.

Analysis of heavy metal content of cadmium (Cd) in milkfish (Chanos chanos Forsk) from milkfish farms in Bima Bay

The research aims to analysis of the content of heavy metals cadmium (Cd) in milkfish (Chanos chanos Forsk) from the encroachment of Bima bay at year 2020. The benefit of this study is to provide information related to the content of heavy metals cadmium (Cd) in milkfish (Chanos chanos Forsk) and protect the community or consumers from heavy metal contaminants. The research was conducted in Bima Bay, namely in 2 research locations, namely Malay village, Bima City, and Palibelo, Bima Regency. This type of research is descriptive explorative research—sampling techniques using purposive sampling. Samples of milkfish were taken directly on the pond area of 3 heads in each location. Then the sample is put in the sample box that has previously been washed clean. The research samples were then analyzed of the content of heavy metal cadmium (Cd) using Atomic Absorption Spectrophotometer tool. The results showed that at the palibelo research site, Bima Regency in PB 1 samples contains cadmium (Cd) of 30 ppm, PB 2 samples of 40 ppm, and PB 3 samples of 10 ppm. Furthermore, at the location of Malay village, Bima City on KM 1 sample of 30 ppm, on KM 2 sample of 40 ppm, and KM 3 sample of 20 ppm. The content of heavy metal cadmium (Cd) in milkfish (Chanos chanos forsk) from Bima Bay exceeds the threshold by BPOM Regulation No. 5 of 2018 is 0.1 ppm. The presence of heavy metal content cadmium (Cd) that exceeds this threshold indicates that the waters of Bima Bay have been contaminated by heavy metals Cadmium (Cd).

Agriculture ecosystem models for CO2 sequestration, improving soil physicochemical properties, and restoring degraded land

Plans outlined in the conference of parties (COP) 26 included the restoration of degraded lands as one of the targets for achieving long-term food sustainability under climate change. The experiment aimed to assess carbon dioxide (CO2) sequestration and improvement in soil physicochemical properties of agriculture ecosystem models. The results of the experiment shows that the bulk density (ρb) and particle density (ρd) were significantly influenced at both depths 0–10 and 10–20 cm in developed ecosystems. The lowest (1.36 g cc−1) and highest (1.57 g cc−1) values of ρb were recorded at the depth of 0–10 cm in forest land (FL) and mono-cropping rice (Oryza sativa) cultivation land (MCRCL), respectively. The minimum values (kg ha−1) of N (161.27), P (14.87), and K (152.07) were recorded at the depth of 0–10 cm in mono-cropping wheat (Triticum aestivum) cultivated land (MCWCL), guava (Psidium guajava) + green gram (Vigna radiata) cultivation land (GGCL), and MCRCL, respectively. Moreover, the maximum N (207.60 kg ha−1) and P (19.27 kg ha−1) were recorded at the depth of 0–10 in FL system, and K (204.60 kg ha−1) in Karonda (Carissa carandas) cultivation land (KCL). The minimum soil N (158.93 kg ha−1) was recorded in pasture land (PL), while P (13.37 kg ha−1) and K (146.0 kg ha−1) was found in MCRCL system at the depth of 10–20 cm. While the highest soil organic carbon (SOC) stock was recorded in FL (18.40 Mg ha−1) and least in MCWCL system (6.57 Mg ha−1). The highest to the lowest value of CO2 sequestration (Mg ha−1) was found in the FL system (115.06) followed by KCL (41.11), GGCL (38.93), MCWCL (22.10), MCRCL (17.65), PL (9.40), and seasonal pond area (SPA 0.87). Likewise, the highest to lowest value of total C credit (US$) was found in FL (342.03) after that KCL (122.2), GGCL (115.71), MCWCL (65.7), MCRCL (52.45), PL (27.94), and SPA (2.6), respectively. With the creation of agricultural ecosystem models on degraded land, this work gives a roadmap for repairing degraded land, enhance the terrestrial CO2 sequestration, C-credit, and boosting ecological services, which may contribute to attaining long-term food sustainability.

The effectiveness of using the synbiotic drug “ProStor” as additives in compound feed when growing carp fingerlings in pond conditions

The stimulating effect of the synbiotic drug “ProStor” on the body weight gain of fish and their physiological state was previously considered in various scientific sources when growing various fish species in swimming pools, cages and experimental aquariums. With the intensification of pond fish cultivation with compacted carp plantings, the percentage of natural forage organisms in the food lump is minimized, and, accordingly, the main weight gain of fish is carried out by feeding with compound feeds. In such conditions, the importance of using probiotic supplements in carp feeding becomes relevant. For a more complete description of the stimulating effect of probiotics, studies were conducted on feeding carp fingerlings in pond conditions of the Saratov region using the synbiotic drug “ProStor”. As a result of the conducted studies, it was revealed that the fish productivity of the outgrowth pond, where young carp were fed mixed feed with the drug “ProStor”, was 20% higher than in the control pond. Higher fish productivity was accompanied by better indicators of carp fingerlings by their average weight, which was 29.6 g and 26.4 g, respectively, in the experimental and control outgrowth ponds. In addition, the use of the developed drug by the company “STC BIO” LLC allowed to reduce feed costs when growing carp fingerlings, which indicates an increasing factor on the quality of compound feed of the synbiotic drug used. On average, the economic efficiency of the use of “ProStor” additives allows you to get an additional profit from one hectare of pond area compared to the control up to 22.5 thousand rubles.

Current status of paddlefish aquaculture development, constraints and future prospects in the world and Russia: a brief review

The current investigation presents the state and prospects for the development of the American paddlefish aquaculture in the world and Russia. The history of American paddlefish culture as a promising invasive species was recorded outside its native ranges in Russia and around the world, especially, Eastern Europe and China. The leading role of the successful Russian trials during the Soviet Union era in the central and southern regions of the country had a significant impact in preserving this species off extinction and even developing the prospects for its cultivation. The historical data on the first three shipments of paddlefish planting material in the 1970s from the United States to the Soviet Union, the stages of acclimatization of this species and the issuance of Russian scientists who made a significant contribution to the development of this fish breeding object are described in detail. The article presents the current state of paddlefish aquaculture, it is indicated that in the presence of a number of restrictions for the large-scale development of paddlefish aquaculture in the country, there are currently about 20 farms engaged in this fish farming object, both for the purpose of experimental and breeding activities, and for obtaining marketable products. But at the same time, it is extremely difficult to judge the state of paddlefish aquaculture due to the lack of statistical data on production volumes from farms, private ownership, which makes it difficult to assess the main fish-breeding indicator — fish productivity of pond areas. Unfortunately, despite a number of advantages of paddlefish for cultivation in water bodies of Russia, aquaculture of this fish species still does not receive proper development for many reasons, and primarily due to the lack of effective technologies for processing marketable fish for the production of gourmet products and extremely weak marketing and advertising activities.

The Preparation of Eco-Friendly Magnetic Adsorbent from Wild Water Hyacinth (Eichhornia crassipes): The Application for Removing Lead Ions from Industrial Wastewater

Water hyacinth ( Eichhornia crassipes) is a wild floating plant that can be found widely in pond or river areas. The plant grows fiercely and causes many harmful issues to the ecosystem around its covered area. This work provides a utilization method that converts wild water hyacinth to reliable magnetic biochar which can be used as a very effective adsorbent for the removal of lead ion Pb(II) in industrial wastewater. The mentioned magnetic biochar can be prepared via a modified pyrolysis process at 550°C with the support of cobalt sulfates as magnetite precursors and limited oxygen from the sweeping gas (the gas mixture ratio is 4 : 1 nitrogen/oxygen). The produced samples were hydrophobic biochar with high oxygen-containing functional groups that are suitable for the removal of inorganic contaminants. The impregnation of cobalt (II, III) oxides provided high magnetic separation performance and additional adsorption sites on the produced magnetic biochar. As indicated by the obtained result, the WHB-Co2M sample possesses a highly porous structure (0.126 cc/g), higher thermal stability (thermal durability reaches 900°C), relatively stable magnetic properties (14.74 emu/g), and a larger surface area (192 m2/g). These beneficial properties led to its suitability to serve as an adsorbent in removing lead ions in the contaminated effluent, recording 95% of removal efficiency and adsorption capacity of 67.815 mg/g. As indicated in the result, all prepared magnetic biochar samples were fitted to two-parameter (Langmuir models) and three-parameter (Sips model) isotherm models. Therefore, the adsorption process in this work could be carried out on both homogeneous and heterogeneous adsorbent surfaces. The adsorption kinetics of the removal process also was described by the pseudo-first-order, pseudo-second-order, and Elovich models to reveal the adsorption and desorption rate of the as-prepared magnetic biochar. This work indicates a successful waste refinery route of converting lignocellulosic biomass such as water hyacinth into value-added material for use as promising heavy metal adsorbents.

Exploring Aquaculture Fish Production: The Case of South Aceh District

This study empirically explores factors determining the production of fish aquaculture in the South Aceh District, Indonesia. The study selected 150 out 1,893 aquaculture fish farmers within 18 sub-districts in the regency as the study’s respondents using a multi-stage sampling technique. Primary data collected through questionnaires’ distribution were analyzed employing a multiple regression model. The research documented empirical evidence that fish pond area, number of fish farmers, and capital significantly and positively influenced the production of fish aquaculture in the South Aceh Regency. Meanwhile, the number of fish seeds had an insignificant impact on the production of fish aquaculture. These empirical results suggested that in improving aquaculture fish production, fish farmers have to possess an adequate amount of capital, pond area, and the number of workers. Soft loan assistance sourced either from the government or banking institutions, conversion of idle and abandoned lands into fish ponds, and various fisheries capacity building programs is among the strategic steps that require to be taken to extend aquaculture production.

TECHNICAL AND FINANCIAL STATUS OF WHITE LEG SHRIMP (Litopenaeus vannamei) FARMING IN FRESHWATER AREAS IN LONG AN PROVINCE

White leg shrimp farming in freshwater area is a spontaneous production activity however that has developed strongly in Long An Province in recent. This study was carried out by surveying 30 shrimp farmers in two freshwater districts of Long An Province including Tan Thanh and Moc Hoa. The result showed that themain technical criteria of shrimp farming were recorded including 0.28 ha of culture pond area, 1.6 m of water level depth, 2.7o=oo of salinity, 88 mg.L-1 of alkalinity, 143 individual.m-2 of stocking density, 86.9 days of culture time, 78.8% of survival rate, 24.7 tons.ha-1.crop-1 of yield and 1.25 of FCR. Regarding the financial status, the total investment cost and profit of shrimp farming were 2,120.8 millions VND/ha/crop and 1,079.6millions VND/ha/crop, respectively. The result of regression analysis showed that the factors including pond area, survival rate of shrimp and FCR were the major factors which had a significant impact on farming productivity. Meanwhile the shrimp farming profit was strongly influenced by 5 main factors including labor cost, feed cost, drug cost, pond renewed cost and shrimp farming productivity.

Experimental hatchery designed for the prawn Macrobrachium nipponense in Marine science center, Basrah, Iraq

This study includes an experimental hatchery design for the oriental river prawn Macrobrachium nipponense from the brackish water of Basrah region (Al-Mashab Marsh). This hatchery consist of five parts: maturation ponds (closed system), hatching of zoug jars, rearing of ponds to larva (nursery and concrete ponds), water tanks and food live of pond (fiberglass). The production capacity was 53,504-190,000 Zoea larvae, 32,355-99,560 Postlarvae. While production of the out ponds (cage two in mud and fiberglass ponds) were estimated between 4,347-24,098 larvae and 2,527-18,828 Postlarvae. Depending on results the total area of the earthen pond and the fiberglass tank, the potential production of Zoea larvae were estimated to be between 36,559-15,300,000 larvae, and between 21,248-11,954,400 Postlarvae. While the total production in all culture systems were 12,600,188-15,760,462 larvae, and between 9,753,349-12,197,630 Postlarvae.

Lead content in soil, plants, rodents, and amphibians in the vicinity of a heating plant's ash waste.

This study supplements previous research focused on environmental condition in the vicinity of waste ash material. The main aim of our study was the comparative analysis of lead levels in soil, plant, and animal organisms in the area of the tailings pond and surroundings, using x-ray. Findings confirm that the level of Pb in the top layer of soil is in the range of 20-135ppm. Lead content in Calamagrostis plant tissues was confirmed only at the tailings pond area, with the highest lead concentrations measured in above-ground components; stems with blooms followed by roots and ground floor sheats. The livers, kidneys, and hearts of Apodemus flavicollis were examined, with findings of higher values in the tailings pond area than in the reference site, and average values of 14.5ppm for livers, 16.0ppm for kidneys, and 16.6ppm for hearts. No significant differences were discovered based on sex and body length/body weight of A. flavicollis individuals. Values for Bombina variegata liver tissue reached an average of 12.3ppm for individuals caught in a water reservoir without ash sediments, versus 15.7ppm in those trapped by the edge of then tailings pond area. Females had lower concentrations of lead than males, but with no statistically significant differences found. Despite lower lead levels in soil and ash than expected, concentrations in mammalian and amphibian organs suggest a possible transition of this element into the food chain, and therefore further research in this area is recommended.

A new strategy to study pond soil chemistry in intensive and extensive cultures of Litopenaeus vannamei: A case study in Brazil

Improvements in the sampling of pond soil and bioremediation techniques can increase the efficiency of soil treatments by emphasizing zones of greater nutrient deposition. This work evaluated the relative deposition of nutrients and their statistical correlation in pond soils in intensive and extensive Litopenaeus vannamei farming. Soil samples were collected (n: 150) in six ponds at two marine shrimp farms (one intensive and one extensive) after being drained and harvesting the shrimp. The ponds were divided into 5 zones - Water Inlet (WI), Water Outlet (WO), Plateau (P), Ditch (D) and Feeder (F), of which five samples were collected in each zone. Soil texture, Total Carbon (TC), Total Organic Carbon (TOC), Total Nitrogen (TN), C/N ratio, Total Phosphorus (TP), Available Phosphorus (AP), aluminum (Al), calcium (Ca), magnesium (Mg), potassium (K) and pH (H2O) were analyzed. All variables were submitted to the Kolmogorov-Smirnov and Levene test to verify normality and homoscedasticity, respectively. Variables that met the requirements were compared by one-way ANOVA analysis of variance, and Tukey test or Student's t-test. The correlation of nutrient concentration was performed using linear regression. Soil from intensive and extensive cultivation ponds were classified as sandy loam and sandy, respectively. The deficiency of carbon and potassium, and excess of phosphorus in the pond soil of both farms was verified. The soil from the ponds of the intensive cultivation farm showed high relative deposition for TC, TOC, TN and AP near the Feeder (F) and the Water Outlet (WO), which infers that these zones (16.32% of the total pond area) may need higher treatment frequencies or different treatment from the other zones studied (WI, P and D). In the soil of the extensive cultivation ponds, the highest values for TC, TOC, TN and AP were found in the Water Inlet (WI), Ditches (D) and Feeder (F) (2.68% of the total pond area). This also indicates the need for higher treatment frequencies or different treatment from the other zones studied (WO and P). In addition, results suggest that phosphorus is the nutrient with the greatest potential for accumulation in the soil, either organically or inorganically, due to its high adsorption potential, occurring mainly in areas of organic matter decomposition regardless of the cultivation system, while nitrogen was mainly organic due to its low adsorption potential. Therefore, based on this study it is recommended that as part of their soil management strategy, shrimp farmers treat the pond areas in a differentiated manner giving special attention to areas of organic matter decomposition with the goal of avoiding waste and increasing production efficiency, potentially saving up to 97% in probiotic products.

Vegetation and fauna features in the zone of influence of the solid waste landfill «Preobrazhenka» (Samara Region)

The anthropogenic factor has a significant impact on the natural-territorial complexes of the Samara Region. Solid waste landfills have a significant impact on the soil and vegetation cover and the animal population, which is due to the alienation of territories as well as the negative impact of leachate and emitted gases into the environment. The purpose of our research is to study the vegetation cover and fauna on the territory of the zone of influence of solid waste landfill Preobrazhenka (Volzhsky District, Samara Region), including the area near the filtrate storage ponds. In the course of the work, geobotanical, floristic, zoological and ecological methods were used. 15 stationary areas were established in the study area around the storage ponds. The authors revealed the composition of phytocenoses, including the associations Galatella villossa Stipa lessingiana, Galatella villossa Stipa lessingiana Onosma simplicissima, Elytrigia repens + forbs, Elytrigia repens Phragmites australis forbs, Elytrigia repens Phragmites australis, Poa angustifolia + Galatella villossa, Quercus robur + Acer platanoides Aegopodium podagraria, Populus tremula Urtica dioica, Poa angustifolia + Galatella villossa, Salix triandra Salix fragilis forbs, Cyclachaena xanthiifolia Polygonum aviculare. The total flora of the territory includes 140 species of vascular plants. The authors have found 36 species of animals, 16 are invertebrates and 20 are vertebrates among them. The general state of biogeocenoses in the area of storage ponds is considered to be unsatisfactory, downstream of the ravine-gully system and on its slopes satisfactory. It is necessary to carry out reclamation of the object.

The ‘Perfect’ Conversion: Dramatic Increase in CO2 Efflux from Shellfish Ponds and Mangrove Conversion in China

Aquaculture, particularly shellfish ponds, has expanded dramatically and become a major cause of mangrove deforestation and “blue carbon” loss in China. We present the first study to examine CO2 efflux from marine aquaculture/shellfish ponds and in relation to land-use change from mangrove forests in China. Light and dark sediment CO2 efflux from shellfish ponds averaged at 0.61 ± 0.07 and 0.90 ± 0.12 kg CO2 m−2 yr−1 (= 37.67 ± 4.89 and 56.0 ± 6.13 mmol m−2 d−1), respectively. The corresponding rates (−4.21 ± 4.54 and 41.01 ± 4.15 mmol m−2 d−1) from the adjacent mangrove forests that were devoid of aquaculture wastewater were lower, while those from the adjacent mangrove forests (3.48 ± 7.83 and 73.02 ± 5.76 mmol m−2 d−1)) receiving aquaculture wastewater markedly increased. These effluxes are significantly higher than those reported for mangrove forests to date, which is attributable to the high nutrient levels and the physical disturbance of the substrate associated with the aquaculture operation. A rise of 1 °C in the sediment temperature resulted in a 6.56% rise in CO2 released from the shellfish ponds. Combined with pond area data, the total CO2 released from shellfish ponds in 2019 was estimated to be ~12 times that in 1983. The total annual CO2 emission from shellfish ponds associated with mangrove conversion reached 2–5 Tg, offsetting the C storage by mangrove forests in China. These are significant environmental consequences rather than just a simple shift of land use. Around 30% higher CO2 emissions are expected from aquaculture ponds (including shellfish ponds) compared to shellfish ponds alone. Total annual CO2 emission from shellfish ponds will likely decrease to the level reported in early 1980 under the pond area-shrinking scenario, but it will be more than doubled under the business-as-usual scenario projected for 2050. This study highlights the necessity of curbing the expansion of aquaculture ponds in valuable coastal wetlands and increasing mangrove restoration to abandoned ponds.