Bottom Of Pond Research Articles

Harnessing sediments of coastal aquaculture ponds through technosols construction for halophyte cultivation using saline water irrigation

The Mediterranean aquaculture has been developed mostly in brackish environment in inactive coastal salt production areas. This study aims to utilise Technosols made with aquaculture sediments for Limonium algarvense Erben cultivation. This species that has nutraceutical potential thrives in halophilic environments in the southwest of the Iberian Peninsula and in Morocco. A microcosm assay was set up with plants grown in bottom sediments (C+), commercial substrate (C−), and Technosols with amendments mixture application at 180 g/kg (Tec180) or at 360 g/kg (Tec360). These plants were irrigated with saline (assay 1) and/or with deionised water (assay 2). The bottom pond sediments, coffee wastes and the estuarine water were evaluated for diverse physicochemical parameters. Plant growth was characterised through a combined methodology using morphometric, SEM and physiological analysis. The Technosols were constructed with bottom sediments and a mixture of organic wastes used as amendments. Results revealed that the bottom sediments had low pH 3.2, Corg and extractable P and K contents, and high electroconductivity (EC) and N–NH4 concentration. The estuarine water had a neutral pH, high EC and high Cl−, HCO3−, Na+, Mg2+ and Ca2+ but low N–NO3- content. The Technosols showed a significant increase of pH, Corg, K and P and a decrease in N–NH4 and EC in comparison with sediments. Principal component analysis separated the different experiments in three groups: C−, A1 and A2 assays. The C− was highly correlated with Corg, P, K, N–NO3 parameters and total ascorbate. The A1 assay showed a strong association with Na, Ca and EC parameters, whereas the A2 assay presented a strongly correlation with plant growth. Plants from Technosols had greater development when irrigated with deionised water than under salty irrigation as opposed to plants cultivated in unamend sediments. In conclusion, these results support that highly saline sediments could be valorised through Technosols construction to cultivate plants with saline water, with potential application in the agro-food and pharmaceutical industry.

Study the effects of different media derived from palm shell for marine shrimp discharge filtration

Marine shrimp culture is important in agricultural sector which generates income for farmers. If marine shrimp culture is not proper management, it can cause environmental impacts on coastal ecosystem and water quality. Some areas use water spraying, washing and then flushing the pond bottom after shrimp harvesting and discharge water to receiving water which high nutrient and suspended solids exceeded the effluent standard. This research studied the marine shrimp discharge filtration using different media derived from palm shell. Three different media types for wastewater filtration were palm shell biochar (B), raw palm shell (R) and palm shell mixed with palm shell biochar (volume ratio of 1:1) (M). The simulated wastewater was daily fed via the top of the filter in semi-continuous mode (8 hours/day) at the hydraulic retention time of 4 h. During the 54 days of operation, water sample was collected to analyse SS, BOD, NH3-N, TP and FCB. At day 54th of operation, the average suspended solids (SS) removal efficiencies of B, R and M were 84, 82 and 84%, respectively, and the average total phosphorus (TP) removal efficiencies were 33, 28 and 30%, respectively. All filters could remove ammonia on the first 30 days of operation in which the concentration met the standard requirement of <1.1 mg/L. The average influent biochemical oxygen demand (BOD) concentration of 27 mg/L can be reduced to less than 20 mg/L after 3 days of operation in all filters. In addition, all filters were able to reduce the fecal coliform bacteria (FCB) to a lower concentration. Thus, these three different media are environmentally friendly material that can be used for effluent water filtration in the small-scale shrimp farm.

Percolation pond with recharge shaft as a method of managed aquifer recharge for improving the groundwater quality in the saline coastal aquifer

The deterioration of groundwater quality has become a serious problem for the safe drinking water supply in many parts of the world. Along coastal aquifers, the saline water moves landward due to several reasons even though significant rainfall is available. The objective of the present study is to investigate the impact of a combined recharge structure including a percolation pond and a recharge shaft in improving the groundwater quality of the surrounding area. The area chosen for this study is Andarmadam, Thiruvallur district of Tamil Nadu. As a part of the study, a suitable site was selected for the construction of a percolation pond based on preliminary field investigations in 2012. Three piezometers were also constructed near the percolation pond to investigate the impact of the structure on groundwater recharge. Further, a recharge shaft was added to this structure in 2013 to overcome the clogging issues at the pond bottom and to enhance the recharge. The impact of the percolation pond on groundwater was assessed by comparing the periodical groundwater level fluctuations with rainfall in the area. The fluctuations in groundwater level near the percolation pond show variations before and after the construction of recharge shaft. The amount of water recharged through the percolation pond during the water year 2012–2013 was estimated as 250–300 m3. The volume of recharge was calculated to be increased more than twice after the construction of recharge shaft inside the percolation pond, on the assumption that recharge through the pond surface remained almost same as before. The dilution of ionic concentration in water was three times higher after the construction of recharge shaft. The long-term groundwater quality in the surrounding area of the pond improves gradually with time. The total dissolved solids (TDS) decrease considerably with time due to the dilution of dissolved solids in water with the fresh water recharging into the aquifer. The Wilcox diagram of most of the water samples after the construction of the recharge structure fall in the excellent to good category, indicating improvement in irrigation water quality.

Improving production and diet assimilation in fish-prawn integrated aquaculture, using iliophagus species

In the integrated culture of pelagic fishes and benthic prawns, a large quantity of nutrients and energy remain in the pond bottom after harvest. This study assessed whether the inclusion of an iliophagus species, such as curimbata (Prochilodus lineatus), can take advantage of those resources and improves yield and diet use efficiency in tambaqui (Colossoma macropomum) and Amazon river prawn (Macrobrachium amazonicum) integrated aquaculture. A completely randomized experiment was designed with two treatments, and five replicates each of integrated systems: tambaqui and Amazon river prawn (TP) and tambaqui, Amazon river prawn, and curimbata (TPC). Ten 0.01-ha earthen ponds were used as experimental unities. Juveniles of tambaqui (3.93 ± 1.63 g) and Amazon river prawn (0.02 ± 0.02 g) were stocked in all ponds at a density of 3 and 11 individuals per m−2, respectively. Five ponds, selected at random, were also stocked with curimbata (3.11 ± 2.61 g) at a density of 5 individuals per m−2. Tambaqui was fed twice a day with an extruded commercial diet (32% crude protein) to apparent satiation. The prawn and curimbata were not fed. The experiment lasted 53 days. The presence of curimbata did not affect tambaqui performance, whereas reduced the production of prawn in ~25%. The inclusion of curimbata increased total species yield by ~35% (from 734 to 991 kg.ha−1) and decreased FCR by ~31% (from 0.61 to 0.42). These results indicate that a mud-feeder like curimbata can take advantage of the large quantity of nutrients and energy deposited in the bottom of freshwater pond aquaculture.

Prawn monosex populations as biocontrol agents for snail vectors of fish parasites

An unresolved problem in aquaculture ponds is the susceptibility of freshwater fish to parasitic diseases, such as those caused by Centrocestus trematodes, which are transmitted by snails of the Thiaridae family. Two species of this family are common in Tilapia aquaculture ponds in Israel, the endemic Melanoides tuberculata and the invasive Thiara scabra, both being hosts of various disease-causing parasitic trematodes. Promising biocontrol agents are freshwater prawns of the genus Macrobrachium, which are known to be voracious predators of freshwater snails. Prawns in contrast to fish, occupy a benthic niche in the aquaculture pond and may thus be expected to prey on disease-carrying snails, which burrow into the pond bottoms. Prawns also bring the added advantage of constituting a high-value side-product to the pond-produced biomass without the need for additional feed. Following recent biotechnological advances in monosex prawn production, non-reproducing monosex prawn populations are now commercially available for testing as ecologically safe biocontrol agents in aquaculture. Laboratory predation experiments examining the ability of monosex Macrobrachium rosenbergii prawns to prey on Melanoides tuberculata and T. scabra snails showed that even a single prawn weighing >4 g is capable of exterminating dozens of snail hatchlings per day and hence of preventing hatchling recruitment in both snail species. Large prawns exhibited significantly superior predation abilities with respect to large snails of both species, with Melanoides snails being more susceptible to predation than Thiara snails. This study is the first to integrate laboratory studies with field observations on the utility of monosex all-female Macrobrachium rosenbergii prawns as biocontrol agents of damaging snails in fish ponds. These prawns were found to be effective biocontrol agents in Tilapia growout aquaculture ponds in terms of reduction in both snail abundance and rates of fish infection with the snail-borne parasites. The promising results of this biocontrol method call for further study aimed at optimizing the biocontrol power and profit of monosex prawn populations in polyculture with fish as part of wider and more comprehensive ecological risk assessment studies.

Nitrate amendment to control sulphide accumulation in shrimp ponds

The production of shrimp is often performed in earthen outdoor ponds in which the input of feed and faeces on the bottom results in deterioration of the water quality that results in a negative impact on the aquatic animals and the environment.Nitrate application in shrimp ponds could improve pond water and sediment quality by oxidizing anaerobic zones of the sediment. This study was conducted to evaluate the possible benefits of nitrate treatment in combination with probiotics application to decrease sulphide formation in shrimp ponds, which is a crucial problem during the growth phase of shrimp. Three sets of experiments were conducted to describe the mechanism of nitrate treatment: a dual dose nitrate treatment at the start and after 14 days that investigated nitrate treatment with concentrations of 50, 100 and 200 mg/L NO3−, a multiple dose nitrate treatment where lower doses of nitrate (12.5, 25 and 50 mg/L NO3−) were tested with more frequent application (every 4 days) and a microbially assisted nitrate treatment in which 50 mg/L NO3− treatment was applied every 4 days with and without presence of a single probiotic application. A batch system including shrimp feed and faeces, representing the bottom waste produced during 90 days of shrimp culture, was used to test the effect of nitrate addition under anaerobic conditions that mimic the dead zones in shrimp pond bottoms where high amounts of organic matter accumulate. Nitrate addition acted as a curative solution for hydrogen sulphide (H2S) accumulation, rather than preventive. Nitrate amended treatments (12.5 mg/L.day NO3) decreased the accumulated H2S in the headspace of incubation bottles by 93 ± 3% compared to the controls. Nitrate addition increased pH and decreased organic acids accumulation to trace amounts. To justify the decrease in H2S concentration apart from the effect sulphur speciation through pH increase, a separate test was conducted to compare the effect of NaOH with nitrate treatment, in which nitrate treatment resulted in a 62.8% higher decrease in H2S concentrations than the NaOH treatment. The use of a denitrifying strain did not improve the beneficial effect of nitrate, indicating that intrinsic capacity for anoxic conversion of waste by the present community was sufficient. In conclusion, nitrate treatment showed a potential to control H2S accumulation in the shrimp ponds that is a critical problem during the growth of shrimp.

Design and implementation of waste cleaning automation system for the shrimp pond bottom

In intensive shrimp cultivation system, residual waste that settled at the bottom of the pond is impacting water quality. Therefore, there is a need to regularly clean this residual to maintain the water quality in good condition. In this paper we describe the automatic instrument system to clean up the bottom of the pond. This waste cleaning instrument uses the principle of equilibrium between the main component in the form of a pyramid and supporting components, namely the water container. The pyramid has a dimension of 2x2x1.3m and 4 poles that serve as rails and support for pulleys that hang both components. The framework of the pyramid is made of pipes and then the frame is coated with HDPE sheets and solar flat. The pyramid will go up and down in accordance with the water container, if it is filled with water and empty automatically because it is installed two submersible pumps to drain and fill the water container. From the field test results it was found that this instrument works effectively, where in one cleaning, it can be done in less than 5 minutes compared to conventional cleaning which takes hours.

Underwater object localization using compressive sensing

In this paper, we propose a technique to localize a moving submerged object with a sparse measurement using a hydrophone array. We used a natural muddy pond bottom with 9 m length, 5.5 m width, and 2 m depth. First, we measured the pond impulse response to identify the sound propagation characteristics. In the second phase namely static direction of arrival (DOA), the underwater speaker was placed at half-circle positions with respect to the array to simulate the underwater object trajectory, 0 deg, 30 deg, 60 deg, 90 deg, 120 deg, 150 deg, and 180 deg, respectively. The sound generated by a four-blade propeller submarine toy was measured to track its trajectory as a dynamic DOA measurement. The measured data were transformed into discrete cosine transform coefficients and reconstructed sparsely by using the basis pursuit algorithm. Based on the estimated incident angle and time delay, the reconstructed measurements were then compared to full dictionary measurement. The results showed that the error angle of the origin deviated about 2.5 deg with half of the measured data were lost. This may suggest that the sound propagation was degraded due to bottom reverberation and scatterers. Currently, we do a similar measurement in an open shallow water environment to eliminate the reverberation.

Pendugaan laju sedimentasi pada kolam tanah budidaya ikan patin intensif di Desa Koto Mesjid Kecamatan XIII Koto Kampar

Potensi perikanan di Koto Mesjid Kecamatan XIII Koto Kampar telah memberikan dampak yang luar biasa bagi pendapatan masyarakat. Total luas kolam Patin di Koto Mesjid telah mencapai 62 hektar. Hasil produksi mencapai enam ton perhari. Pelatihan pendugaan laju sedimentasi pada kolam tanah budidaya ikan patin intensif di desa Koto Mesjid telah menghasilkan cara pemantauan kualitas air kolam melalui pengukuran padatan tersuspensi menggunakan alat perangkap padatan. Rata-rata padatan tersuspensi pada semua umur kolam adalah 19,5 ml/L perhari dan 129,25 ml/L per minggu. Berdasarkan data ini maka pengelolaan dasar kolam harus dilakukan setiap panen terutama saat pengeringan kolam perlu pengurasan lumpur. Petani ikan Patin memiliki antusias sangat tinggi untuk mempraktekkan alat pada kolam masing-masing. Adanya penyuluhan ini sangat bermanfaat dalam memberikan bekal ilmu pengetahuan sehingga masyarakat yang berprofesi sebagai petani ikan Patin dapat mengatur waktu penggantian air kolam dengan mudah.

Effect of three types of liquid compost combined with Avicennia marina leaves on growth and survival of tiger prawns (Penaeus monodon)

The sustainability of prawn farming in brackish water ponds is controversial because of low yields and a history of mangrove clearing. Low yields are due largely to insufficient preparation of pond bottoms. Mangrove trees are often planted on pond bunds as window dressing. This study examines the effect of three types of liquid compost from vegetable, fruit, and both vegetable and fruit in tanks to which whole or chopped Avicennia marina leaves have been added to mimic local pond conditions. In a split-plot design, 28 square tanks were each stocked with one hundred 15-day-old post-larvae tiger prawns (Penaeus monodon). Four tanks were used as controls and 24 were assigned to the treatments, 12 with whole and 12 with chopped leaves. Of the treatment tanks, 4 received liquid compost from vegetable, 4 received fruit, and 4 received mixed vegetable and fruit. Shrimp were weighed at the start, halfway point, and the end of the 50-day trial, and fed at 5% of the estimated total weight; survival was counted at the end. The survival rates of treatments and controls (65–76%) were not significantly different. Shrimp in water with vegetable compost grew significantly faster (2.7% day−1) than in both treatments with fruit (2.5% day−1), while all treatments were associated with significantly faster growth than were the controls (2.0% day−1). The lower growth rate of shrimp fed fruit compost may have been due to dinoflagellates, which are known to negatively affect shrimp. Shrimp in tanks with chopped mangrove leaves grew slightly better than shrimp in tanks with whole mangrove leaves.

The budget of nitrogen in the grow‐out of the Amazon river prawn ( Macrobrachium amazonicum Heller) and tambaqui ( Colossoma macropomum Cuvier) farmed in monoculture and in integrated multitrophic aquaculture systems

This work determined the nitrogen inputs, outputs and accumulation in compartments of stagnant earthen ponds for the monoculture and integrated multi-trophic aquaculture (IMTA) of the Amazon river prawn (Macrobrachium amazonicum) and tambaqui (Colossoma macropomum), using recycled hypereutrophic water. A completely randomized experiment was designed with four treatments and three replications: PM–monoculture with 30 prawns/m2, FM - monoculture with 3 fish/m2, IMTA - polyculture with 30 prawns/m2 and 30 fish/m2 free, POLY-CAGE - polyculture with 30 prawns/m2 free and 40 fish/m3 in net-cages. Animals, rain, water, feed, soil, gas, accumulated sludge, and suspended sediments were collected throughout the experiment to determine their nitrogen contents and to calculate the nitrogen budget. Results showed that much of the nitrogen available escapes to atmosphere as N2 (~40%–56%) after denitrification or accumulated within bottom sludge (~14%–42%). The remaining nitrogen was converted in animal biomass (~5%–21%) or was discharged to receiving waterbodies in the outlet water (~11%–13%). Feed management appeared to influence the major biological processes in the aquatic nitrogen cycle, such as photosynthesis and denitrification. The fish-prawn IMTA systems converted approximately 53%–75% of feed nitrogen into harvestable products, which is more efficient than the 19%–46% of feed nitrogen converted in the monocultures. However, a large amount of nitrogen is accumulated in the pond bottom in all systems. An increased prawn density or the addition of a mud-feeder species to the culture may enhance the incorporation of this material in harvested biomass, improving the efficiency of the systems.

An Ethnolinguistic Study in the Names of Salt Farming Tools in Rembang District

The aim this research was to describe the names of the tools used in salt farming in Rembang district, which was viewed from an ethnolinguistic perspective. This research was a qualitative research using the Spradley ethnographic method. Data collection used participatory observation and interview techniques. The collected data were analyzed using the ethnosains analysis model. The results show that salt farmers in Rembang regency know at least 13 names of tools in salt farming, namely: ebor, sirat, kincir, desel, garuk, kusut, slender, ekrak, tolok, mbatan, angkong, dium, and ukuran banyu. The thirteen tools can be classified according to their functions, such as (1) to move seawater; (2) to flatten the pond bottom; (3) to compact the pond bottom; (4) to move the salt into a sack or conveyance; (5) to transport the salt in storage area; (6) for coating the bottom of the pond; (7) to determine the density of seawater in the pond.

Riparian leaf litter decomposition on pond bottom after a retention on floating vegetation.

Allochthonous (e.g., riparian) plant litter is among the organic matter resources that are important for wetland ecosystems. A compact canopy of free‐floating vegetation on the water surface may allow for riparian litter to remain on it for a period of time before sinking to the bottom. Thus, we hypothesized that canopy of free‐floating vegetation may slow decomposition processes in wetlands. To test the hypothesis that the retention of riparian leaf litter on the free‐floating vegetation in wetlands affects their subsequent decomposition on the bottom of wetlands, a 50‐day in situ decomposition experiment was performed in a wetland pond in subtropical China, in which litter bags of single species with fine (0.5 mm) or coarse (2.0 mm) mesh sizes were placed on free‐floating vegetation (dominated by Eichhornia crassipes, Lemna minor, and Salvinia molesta) for 25 days and then moved to the pond bottom for another 25 days or remained on the pond bottom for 50 days. The leaf litter was collected from three riparian species, that is, Cinnamomum camphora, Diospyros kaki, and Phyllostachys propinqua. The retention of riparian leaf litter on free‐floating vegetation had significant negative effect on the carbon loss, marginal negative effects on the mass loss, and no effect on the nitrogen loss from leaf litter, partially supporting the hypothesis. Similarly, the mass and carbon losses from leaf litter decomposing on the pond bottom for the first 25 days of the experiment were greater than those from the litter decomposing on free‐floating vegetation. Our results highlight that in wetlands, free‐floating vegetation could play a vital role in litter decomposition, which is linked to the regulation of nutrient cycling in ecosystems.

Respuesta de comunidades de invertebrados bentónicos en estanques cambiados por el río debido a la modificación del hábitat del río en áreas con deficiencia de agua

In water-deficient area, river-changed ponds are common and vital for aquatic species. This paper studies the relationship between the environmental factors and the benthic invertebrate communities in varying ponds under river habitat modifications (RHM). For analysis, numerous samples are collected from river-changed ponds in Beijing, China. These ponds are classified into five types, including totally reinforced ponds, channel reinforced ponds, bank reinforced ponds, natural ponds, and restored ponds. Results indicate: 1) the biodiversity of benthic invertebrates is dependent strongly on the pond type; 2) habitat quality explains a considerable amount of variations in benthic invertebrate communities, and RHM show strong power in explaining variations in habitat quality; 3) RHM on the pond bank has stronger impact on the habitat quality than that on the pond bottom. These findings suggest that RHM can affect the benthic invertebrate community through changing the habitat quality. And we suggest that ecological restoration of pond bank should be a useful way to improve invertebrate biodiversity for rive-changed ponds in Beijing.

Flow characteristics and energy dissipation of an offset jet in a rectangular stormwater pond

This paper presents a numerical modeling of a circular submerged offset jet in a rectangular stormwater pond and investigates various design parameters (inlet offset position, tailwater depth, bottom roughness, and basin width and length) on jet velocity decay and energy dissipation. Results from the numerical model suggest that the energy dissipation increases with a deeper pond tailwater depth, and decreases with offset height when the offset height is less than half of the tailwater depth. Additionally, the basin width and pond length will affect the velocity decay rate and energy dissipation. Riprap installed at the pond bottom has little influence on energy dissipation in the studied cases. Findings from this study can be useful in pond design for bottom erosion protection and improved energy dissipation.

The response of cucumber plants (Cucumis sativus L.) to the application of PCB-contaminated sewage sludge and urban sediment.

BackgroundThe increasing production of sewage sludge (SS) engenders the problem of its responsible utilization and disposal. Likewise, urban sediments (SED) are deposited at the bottom of urban reservoirs and sedimentation ponds, and these require periodical dredging and utilization. However, while the SS and SED deposits often contain nutrients such as nitrogen and phosphorus; however, they also contain a variety of hazardous compounds including heavy metals, Persistent Organic Pollutants (POPs) and microbial pollutants. Fortunately, some species of Cucurbitaceae can accumulate high levels of POPs, such as polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB), in their tissues.MethodsSS was collected from the Lodz Municipal Wastewater Treatment Plant and SED from the Sokołówka Sequential Biofiltration System. The SS and SED samples were added to soil in flower pots at three concentrations (1.8 g, 5.4 g and 10.8 g per flower pot), and one pot was left as an unamended control (C). Soil PCB concentrations were determined before cucumber planting, and after five weeks of growth. Also, total soluble protein, total chlorophyll content, chlorophyll a/b ratio and degree of lipid peroxidation (TBARS) were examined in the leaves of the cucumber plants (Cucumis sativus L.) cv. Cezar after five weeks. Antioxidative response was assessed by ascorbate peroxidase (APx) and catalase (CAT) assay.ResultsThe initial PCB concentration in soil after application of SS or SED was dependent on the applied dose. After five weeks, PCB concentration fell significantly for all samples and confirmed that the dose of SS/SED had a strong effect. Soil remediation was found to be more effective after SS application. Total soluble protein content in the cucumber leaf tissues was dependent on both the type and the dose of the applied amendments, and increased with greater SS doses in the soil. The total chlorophyll content remained unchanged, and the chlorophyll a/b ratio was slightly elevated only after the application of the highest SS and SED dose. The use of SS and SED did not significantly affect TBARS content. APx activity fell after SS or SED application; however, CAT activity tended to increase, but only in the leaves of plants grown in SS-amended soil.DiscussionThe cultivation of cucumber plants reduces PCB concentration in soil amended with SS or SED; however, this effect is more evident in the case of SS. SS application also induced more intensive changes in the activity of enzymes engaged in antioxidative response and oxidative stress markers in plant tissues than SED. The levels of PCB in the SS may have triggered a more severe imbalance between pro- and antioxidative reactions in plants. Cucumber plants appear to be resistant to the presence of toxic substances in SS and SED, and the addition of SS and SED not only acts as a fertilizer, but also protects against accelerated aging.

Environmental Sources of Bacteria and Genetic Variation in Behavior Influence Host-Associated Microbiota.

In many organisms, host-associated microbial communities are acquired horizontally after birth. This process is believed to be shaped by a combination of environmental and host genetic factors. We examined whether genetic variation in animal behavior could affect the composition of the animal's microbiota in different environments. The freshwater crustacean Daphnia magna is primarily planktonic but exhibits variation in the degree to which it browses in benthic sediments. We performed an experiment with clonal lines of D. magna showing different levels of sediment-browsing intensity exposed to either bacteria-rich or bacteria-poor sediment or whose access to sediments was prevented. We found that the bacterial composition of the environment and genotype-specific browsing intensity together influence the composition of the Daphnia-associated bacterial community. Exposure to more diverse bacteria did not lead to a more diverse microbiome, but greater abundances of environment-specific bacteria were found associated with host genotypes that exhibited greater browsing behavior. Our results indicate that, although there is a great deal of variation between individuals, behavior can mediate genotype-by-environment interaction effects on microbiome composition.IMPORTANCE An animal's behavior can affect its risk of infection, but it is not well understood how behavior affects microbiome composition. The aquatic crustacean Daphnia exhibits genetic variation in the extent to which it browses in the sediment at the bottoms of ponds. We show that this behavior affects the Daphnia microbiome, indicating that genetic variation among individuals may affect microbiome composition and the movement of bacteria in different environments.

Using of Electrodeposition Technique to remove Ra-226 from Contaminated soil

The aim of this study was to remove Ra-226 from the contaminated soil samples which collected from one of oil company located at western desert of Egypt. Five soil samples (S-1, S-2, S-3,S-4,S-5) were collected from the bottom of evaporation pond from different positions of dry evaporation pond inside the oil company. The activity concentration of Ra-226 measured by using the Hyper Pure Germanium detector (HPGe) connected to MCA . Electrodeposition technique was used to produce in situ metallic coatings by the action of an electric current on a conductive material immersed in a solution containing a salt of the metal to be deposited. Chemical agents added to the solution to increase the efficiency of contaminant removal nitric acid HNO3 was added to improve the solubility of Ra-226. Three different electrods made from stainless steel, aluminum and cupper poles were used in this study. The data obtained showed that the highest removal percentage of the Ra-226 found to be 73% when the aluminum pole was used. Therefore, from the obtained data, it is clear that the electrodeposition technique using aluminum poles for removal of Ra-226 can be used for remediation or treatment contaminated soil produced from oil industry.

Water circulation induced by mechanical aerators in a rectangular vessel for shrimp aquaculture

A water streamer was designed for the purpose of enhancing cost-efficient circulation between the water surface and bottom of shrimp aquaculture ponds. We took direct measurements of the water current field induced by the designed aerator in a large rectangular reservoir of dimensions (L)50 × (W)19 × (D)1.3 m3 and compared the results with those of a standard Taiwanese paddle-wheel aerator. Vertical circulation between the surface and the bottom induced by the paddle wheel aerator was less than that by the designed aerator. Furthermore, the paddle-wheel aerator consumed more electric power than the designed aerator. The structures of water current induced by the two aerators are elucidated, and the advantages and disadvantages of the aerators are discussed.Auxiliary employment of the designed aerators may contribute to delivery of high DO water throughout the pond, which is more efficient than a paddle wheel aerator.

Functions of traditional ponds in altering sediment budgets in the hilly area of the Three Gorges Reservoir, China

The landscape pattern will affect the sediment transport process. The cluster of ponds is a common landscape, which has traditionally been used for irrigation in the hilly area of the Three Gorges Reservoir (TGR). However, little is known about how the landscape elements temporally changed over the past decades and if the ponds can be applied to function in balancing watershed sediments against soil erosion. The Jinglingxi watershed, covering 20.5 km2, was selected as the study area. The changes in pond number, surface area, and drainage catchment were analyzed with aid of high-resolution typographical map and unmanned aerial vehicles imagery. The spatial WaTEM/SEDEM model was developed to simulate watershed soil erosion and sediment deposition under the absence and presence of water bodies scenarios. Results from different simulation scenarios were compared and revealed the trapping effects of the multi-pond system. From 1983 to 2016, the number and total area of ponds roughly doubled. The density reached 30 ponds/km2. From 1983 to 2016, the total drainage area of ponds increased from 13.22% to 35.4% of the whole watershed. The sediments deposited at the bottom of ponds can indicate the past specific sediment yield (SSY) in drainage catchments. Our results suggest that the multi-pond system not only reduce watershed sediment export but also alter the sediment deposition in different land uses. The reduced sediments export is expected to prolong the service life of downstream reservoirs at the expectancy of ponds' storage capacities. The ecological compensation from downstream reservoirs' revenues to upstream regions should be established to drive dredging actions for the upstream ponds.