Pond Types Research Articles

The Differences Effect between Pond Types and Maggot Allotments on The Protein and Fat of Tilapia Meat

Tilapia was one of the freshwater fish commodities that were widely consumed, so the demand for tilapia increased and impacted the high price of tilapia feed. Therefore, maggots can be used as additional fish feed, and recently there have been many variations of pond types in tilapia farming. This study aimed to determine the interaction between pond types and maggot allotments for protein and fat in tilapia meat. This study used two types of pools: tarpaulin and drum. The subjects used in this study were tilapia, with as many as 30 fish per pond. The dependent variables in this study were the protein and fat of tilapia meat. This study used the factorial method with a completely randomized design (RAL) with four treatments; each of the four tests consisted of A1B1 (Tarpaulin pool and maggots), A1B2 (Tarpaulin pool without maggots), A2B1 (Drum pool and maggots), and A2B2 (Drum pool without maggots). Data analysis was done using ANOVA with a significance level of 5% if there is an effect continued Duncan test. The results of this study showed no noticeable effect on meat protein (0.253>0.05) and meat fat (0.067>0.05) tilapia.

The prevalence, antibiotic resistance and multilocus sequence typing of colistin-resistant bacteria isolated from Penaeus vannamei farms in earthen ponds and HDPE film-lined ponds in China.

The aquaculture environment, especially the culture ponds and aquaculture products, is considered to be an important reservoir of colistin resistance genes. However, systematic investigations of colistin resistance in Penaeus vannamei farming in different culture modes are scarce. In this study, a total of 93 non-duplicated samples were collected from P. vannamei farms in five cities in China from 2019 to 2021. The prevalence, antibiotic resistance and multilocus sequence typing (MLST) of colistin-resistant bacteria were measured and analysed. The results showed that among the 1601 isolates in P. vannamei and its environmental samples, the pollution of colistin-resistant bacteria was serious (the overall prevalence was 37.3% and 28.8%, respectively), regardless of the earthen pond or high-density polyethylene (HDPE) film-lined pond. Among 533 isolates, the prevalence of mobile colistin resistance (mcr) genes, mcr-1, was the highest (60%, 320/533), followed by mcr-4 (1.5%, 8/533), mcr-8 (0.9%, 5/533), mcr-10 (0.6%, 3/533) and mcr-7 (0.4%, 2/533). The prevalence of mcr-1 in earthen ponds was significantly higher than that in HDPE film-lined ponds (67.5% vs. 49.1%, p < .001). The dominant strain carrying mcr-1 was Bacillus spp. (54.1%, 173/320), followed by Enterobacter spp. (8.1%, 26/320), Staphylococcus spp. (6.3%, 20/320) and Aeromonas spp. (5.3%, 17/320). The antibiotic resistance profiles of 173 Bacillus spp. varied among different sampling locations and culture types. These isolates were highly resistant to cefepime, ceftriaxone, trimethoprim-sulfamethoxazole and ceftiofur (>45%), and multidrug-resistant isolates were common (62.4%, 108/173). Sequence type (ST) 26 (37/66, 56%) was found to be the most prevalent ST in mcr-1-positive Bacillus cereus isolated from the aquaculture environment. In summary, our study pointed out that it is necessary to continuously monitor antibiotic usage and its residues regardless of the pond types, especially with regard to critical drugs such as colistin.

A method to derive satellite PAR albedo time series over first-year sea ice in the Arctic Ocean

Deriving sea ice albedo from spaceborne platforms is of interest to model the propagation of the photosynthetically available radiation (PAR) through Arctic sea ice. We show here that use of the Moderate Resolution Imaging Spectroradiometer (MODIS) operational surface reflectance satellite product to derive albedo in the PAR spectral range is possible. To retrieve PAR albedo from the remote sensing surface reflectance, we trained a predictive model based on a principal component analysis with in situ and simulated data. The predictive model can be applied to first-year sea ice surfaces such as dry snow, melting snow, bare ice and melt ponds. Based on in situ measurements and the prescribed atmospheric correction uncertainty, the estimated PAR albedo had a mean absolute error of 0.057, a root mean square error of 0.074 and an R2 value of 0.91. As a demonstration, we retrieved PAR albedo on a 9-km2 area over late spring and early summer 2015 and 2016 at a coastal location in Baffin Bay, Canada. On-site measurements of PAR albedo, melt pond fraction and types of precipitation were used to examine the estimated PAR albedo time series. The results show a dynamic and realistic PAR albedo time series, although clouds remained the major obstacle to the method. This easy-to-implement model may be used for the partitioning of PAR in the Arctic Ocean and ultimately to better understand the dynamics of marine primary producers.

PHYTOPLANKTON COMMUNITY PROFILE IN INDOOR AND OUTDOOR WHITE LEG SHRIMP (Litopenaeus vannamei) INTENSIVE CULTURE

Water quality can change according to the availability, abundance, and composition of phytoplankton in these waters. The fertility of a waters can be reviewed by observing the phytoplankton community in it. The purpose of this study was to determine the effect of using different types of ponds, namely indoor and outdoor, on the diversity and abundance of phytoplankton and water quality. This research was carried out in six different ponds consisting of three indoor pools and three outdoor pools for 56 . Samples of phytoplankton in indoor and outdoor ponds were taken as many as 4 points each. The abundance of phytoplankton in indoor ponds ranged from 880-9482 ind/L while at outdoor ponds ranged from 506-3344 ind/L., which generally consist of 5 phyla, i.e. Bacillariophyta, Charophyta, Chlorophyta, Cyanobacteria, and Glaucophyta. The highest abundance of phytoplankton was found in the indoor pondl (A2) of 5979.60±3353.59 ind/L , while the lowest was in the outdoor pool (B3) of 1350.80±628.75 ind/L . Comparison of the abundance of phytoplankton in indoor and outdoor ponds showed significantly different results. Water quality measurements showed that the indoor was better than the outdoor ponds

Demonstration study of bypass stabilization pond system in the treatment of eutrophic water body.

This study involved a comprehensive renovation of fish ponds to improve the water quality of a eutrophic river in Dongguan City. The abandoned fish ponds were transformed into three different types of stabilization ponds: facultative, aerated biological, and submerged plant stabilization ponds. The water of the eutrophic section of the river was pumped into the facultative stabilization pond and discharged into the Haizai River through an aerated biological pond and a submerged plant pond. In the aerated biological pond, secondary treatment was carried out using plant zoning and artificial floating island aeration system. The submerged plant pond used fountain-type aeration and an underwater forest for tertiary treatment. After four months of monitoring the water quality of the stabilization pond and the river, the ammonia nitrogen (NH3-N), total phosphorus (TP), and chemical oxygen demand (CODCr) levels in the raw sewage reduced from 6.53 mg/L to 1.13 mg/L, 1.76 mg/L to 0.29 mg/L, and 63 mg/L to 22 mg/L, respectively; the transparency of water increased to 45 cm, and dissolved oxygen (DO) level increased to 5.32 mg/L. This study provides a reference for the ex-situ treatment of urban eutrophic waterbodies.

Strong Behavioral Effects of Omnivorous Fish on Amphibian Oviposition Habitat Selection: Potential Consequences for Ecosystem Shifts

Perceived predation risk to offspring may have similar ultimate community-level impacts to those of consumptive trophic interactions. The present study investigated the behavioral effects of common carpCyprinus carpio–an omnivorous fish capable of triggering an ecosystem shift to an algae-dominated state–on anurans, using a natural experiment conducted in a system of fish-stocked ponds. We compared oviposition patterns and larval densities of anurans and abundance of zooplankton and phytoplankton in ponds where fish were virtually absent and ponds where common carp was dominant. All studied anuran species bred in fish-poor ponds, while in ponds with high fish densities most of them oviposited infrequently or virtually did not breed. Oviposition habitat selection coupled with fish trophic pressure resulted in diametrically different tadpole densities between fish-poor and fish-dominated ponds. The alimentary tract contents of tadpoles of three locally common anurans,Pelobates fuscus,Hyla orientalis, andRana temporaria, contained large numbers of unicellular algae, but also significant numbers of zooplanktonic grazers. According to stable nitrogen isotope analyses, tadpoles occupied a trophic level similar to a primary consumer, snailLymnaea stagnalis, indicating that they fed mainly on algae. While total biomass of crustacean zooplankton did not differ between pond types, chlorophyllaconcentrations were low in fish-poor ponds compared to fish-dominated ponds and negatively related to total tadpole biomass. Our findings indicate that scarcity of anuran larvae, resulting mainly from the behavioral responses of breeding anurans to fish predation risk, may facilitate algal production, although ecosystem shifts in the presence of fish occur along more pathways than a top-down cascade.

Unexplored freshwater communities in post‐mining ponds: effect of different restoration approaches

Many studies examining plant and terrestrial invertebrate communities have revealed the high conservation potential of spoil heaps. On the other hand, the freshwater communities inhabiting post‐mining ponds within these human‐made habitats are almost unexplored. We focused on aquatic macroinvertebrate, zooplankton, and phytoplankton communities in the littoral zones of 24 ponds situated on spoil heaps created after lignite mining in the Czech Republic. We compared environmental factors, taxa richness, and conservation value (number of threatened aquatic macroinvertebrate species) in the ponds, based on the type of restoration approach applied, that is, technical reclamation, spontaneous succession, and their combination (semi‐spontaneous succession). While macroinvertebrate and zooplankton taxa richness did not differ significantly between the three types of pond, the phytoplankton community did, with the highest taxa richness recorded in technically established ponds. From a nature conservation point of view, the spontaneously developed ponds hosted almost twice as many threatened macroinvertebrates as the other ponds; nevertheless, even the technically constructed ponds hosted considerable populations of rare species, e.g. the regionally extinct beetle Limnebius nitidus (Marsham, 1802), and contributed to the overall conservation value of the spoil heaps. The most significant driver structuring post‐mining pond freshwater communities was the percentage of vegetation in the littoral zone.

Pollution and Release Characteristics of Nitrogen, Phosphorus and Organic Carbon in Pond Sediments in a Typical Polder Area of the Lake Taihu Basin

There is currently a lack of knowledge on the release characteristics of nutrients from artificial pond sediments in polder areas, resulting in problems in future management of such environments, including converting polders to lakes. In this study, sediment samples were taken from a fish pond and a lotus pond in a typical polder area of the Lake Taihu Basin in China. The total nitrogen (TN, 1760–1810 mg/kg), total phosphorus (TP, 1370–1463 mg/kg) and total organic carbon (TOC, 10.1–21.2 g/kg) contents were significantly higher than those found in sediments from the adjacent aquatic system, which indicates that the legacy of agricultural activities has had an obvious cumulative effect on pond sediment nutrients. The release behavior of TN, TP and TOC varied significantly, not only under disturbed and static conditions, but also from sediments sampled at different ponds and depths. During the disturbing condition, there were continuous releases of carbon and nutrients in the lotus pond sediments, while the fish pond sediments showed a higher release at the beginning. Under static release conditions, the release of TP in the surface and bottom sediments of the fish pond increased first, then decreased and stabilized within 24 h, while the release of the lotus pond showed a slow upward trend. Despite the lower concentration of nutrients and TOC, the lotus pond sediment showed a higher release rate. The results suggested that it is necessary to adopt different strategies for different types of ponds in the project of returning polders to lakes; it is especially important to pay attention to the release of nutrients from the bottom sediments of lotus ponds in the project management.

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.

ECONOMIC ANALYSIS AND FOOD SECURITY CONTRIBUTION OF SUPPLEMENTAL IRRIGATION AND FARM PONDS: EVIDENCE FROM NORTHERN BURKINA FASO

The dry spells are severe obstacles to rainfed agriculture in Sahelian countries. The farmers believe supplemental irrigation is an excellent way to adapt rainfed agriculture to dry spells. In this study, we analyzed the contribution of supplemental irrigation to food security and compared the profitability of different types of ponds constructed by farmers in northern Burkina Faso. Human cereal requirement was used as indicators to analyze the contribution of supplemental irrigation to food security. The criteria for analyzing the profitability of the selected ponds were gross margin (GM), net present value (NPV), internal rate of return (IRR) and payback period (PBP). The results show that the additional yield of corn obtained with supplemental irrigation makes it possible to meet the monthly cereal needs of at least 17 people and generates an additional GM of FCFA 178,483 (US$ 309.26) compared to no irrigation. The estimate of the NPV, from IRR and PBP showed that the profitability of supplemental irrigation in 15 agricultural seasons varies between type of ponds constructed. Given the up-front cost and the farmers’ lack of resources, the ponds require a subsidy or a credit policy to facilitate the adoption of supplemental irrigation in Sahelian countries.

Economic analysis and food security contribution of supplemental irrigation and farm ponds: evidence from northern Burkina Faso

BackgroundDry spells are serious obstacles to rainfed agriculture in Sahelian countries. Various water harvesting techniques are used by farmers to reduce the impact of climate variability, but are not sufficient in the case of a prolonged drought lasting 2–3 weeks. The farmers believe supplemental irrigation is a good way to adapt rainfed agriculture to dry spells. In this study, we evaluated the food contribution and profitability of supplemental irrigation of rainfed crops comparing various farm ponds that collect runoff water from the surrounding landscape.MethodsWe analyzed the contribution of supplemental irrigation to food security and compared the profitability of different types of ponds constructed by farmers in northern Burkina Faso. Human cereal requirement was used as indicators to analyze the contribution of supplemental irrigation to food security. The criteria for analyzing the profitability of the selected ponds were gross margin (GM), net present value (NPV), internal rate of return (IRR) and payback period (PBP).ResultsOur results show that the additional yield of corn obtained with supplemental irrigation makes it possible to meet the monthly cereal needs of at least 17 people and generates an additional GM of FCFA 178,483 (US$ 309.26) compared to no irrigation. The estimate of the NPV, from IRR and PBP showed that the profitability of supplemental irrigation in 15 agricultural seasons varies between the type of ponds constructed.ConclusionsGiven the up-front cost and the farmers’ lack of resources, the ponds require a subsidy or a credit policy to facilitate the adoption of supplemental irrigation in Sahelian countries. However, the irrigation strategies to optimize agricultural income remain a field of research to be explored.

Comparison of Classification Algorithms for Detecting Typical Coastal Reclamation in Guangdong Province with Landsat 8 and Sentinel 2 Images

Coastal reclamation in Guangdong Province is highly concentrated and is growing rapidly. However, intensive reclamation use has resulted in serious influence on the coastal ecosystem, directly and indirectly. The current conditions and spatial distribution of reclamations must be detected for coastal preservation and management using efficient technology. This study aims to find a suitable method and data to map reclamations accurately at a large scale. Pixel-based and object-oriented classification methods were applied in extracting the three typical types of coastal reclamation, namely, ports, aquaculture ponds, and salt pans, in Guangdong Province from Landsat 8 and Sentinel 2 images. The algorithms of a support vector machine, random forest, decision tree, and rule-based algorithm were performed. Classification results were compared with statistical measures to assess the performance of different algorithms. The results indicated that all of the algorithms could obtain classification results with high accuracy, whereas the object-oriented algorithm showed less efficiency than other algorithms in classifying ports with complicated features. High-resolution data were not always superior to lower-resolution data in the reclamation classification. Generally speaking, applying the rule-based object-oriented algorithm in Sentinel 2A MSI images is relatively efficient at detecting the reclamation use in coastal Guangdong considering its actual situation. The mapping of reclamations in the whole of coastal Guangdong shows that they present obvious agglomeration characteristics in the space. The aquaculture ponds are mainly distributed in the coastal zones of western Guangdong and eastern Guangdong, with the largest area of 77,963 ha. The other types of ports are mainly distributed in the coastal zones of the Pearl River Delta, with an area of 8146 ha, while salt pans are mainly distributed in the coastal zones of Jiangmen, Zhuhai, and Zhongshan, with a total area of 4072 ha. The results can provide key supporting data for decision making in coastal management and preservation.

Effect of the Site and the Type of Fertilizer on the Taxonomic Composition and Abundance of Phytoplankton Population of Ponds in West Cameroon

Pond fertilization is an age-old practice aimed at optimizing yields in so-called production fish farming systems. With this in mind, a characterization study of phytoplankton, the basis of the trophic food chain leading to fish, was conducted from January to December 2021 in ponds in the West Cameroon regionand at the Research Unit of Ichthyology and Applied Hydrobiology of the University of Dschang. To do this, a total of fifteen (15) ponds including 03 in Bamendou fertilized with cowpat, 04 in Batie including 02 fertilized with pig manure and 02 with wheat bran, 01 in Dschang fertilized with chicken manure, 04 in Fokoue including 02 fertilized with pig manure and 02 unfertilized and 03 in Foumbot fertilized with cowpat, were considered. These ponds were chosen based on the availability of fish farmers and the type of fertilizer administered. Sampling of biotic characteristics including phytoplankton richness, relative abundance and density was done between 6 and 8 a.m. following a monthly frequency. The results showed that the highest specific richness (42.73% of total species richness) was observed in Batie ponds fertilized with pig manure and generic richness (81.53% of total genera richness) and families (84.21% oftotal of families richness) highest phytoplankton in Batie ponds fertilized with wheat bran. Regardless of the type of pond, Chlorophyta were more abundant (40.50%). With the exception of Chrysophyta who were absent in the ponds of Foumbot fertilized with cowpat, all other groups were listed in the different types of ponds. The significantly (p&lt;0.05) highest phytoplankton density (71. 107 ind/L) was observed in ponds fertilized with chicken manure with high concentrations of nitrates and nitrites.

Sustainable Urban Design Guidelines for Different Types of Urban Ponds: A Case Study of Sylhet, Bangladesh

Urban ponds are one of the essential natural elements that have supported urban communities with ecological benefits as well as sociocultural and economic activities throughout the ages. These ponds are presently facing existential threats due to increased urbanisation and the lack of available space in the cities. Sylhet, one of the most prominent cities in Bangladesh, is expanding at an unprecedented rate. Migrants are making the city’s inner circle more populated, raising more pressure on building density, and ponds and open spaces are being filled up. As a result, urban dwellers’ living conditions are worsening due to the lack of natural areas and the growing number of environmental issues. People are losing access to ponds and open spaces and shifting away from their traditional lifestyles. Meanwhile, the municipality is working diligently to address these issues, but a collaborative effort between the community and the municipality is required to resolve the difficulties. This paper aims to analyze the importance and current status of the city’s existing ponds and establish development guidelines for the ponds, so they can be designed and protected sustainably. Some findings of a survey conducted among the local communities have been presented. Their opinions about these natural elements and reviews from previous research are discussed and analyzed, leading to the design implications for the sustainability of the urban ponds and a sustainable future city.

Incorporating dynamics of land use and land cover changes into tsunami numerical modelling for future tsunamis in Banda Aceh

This study aims to investigate the tsunami exposure to current land use land cover (LULC) with the LULC predictions for the next 50 years, including the impact of sea-level rise (SLR) in Banda Aceh. This study began with a spatio-temporal dynamic analysis using LULC changes projection. Firstly, Markov Chain was used to simulate the changing trends in land use from 2011 to 2015. The changing trends were used to simulate land use predictions for 2015-2065 using Cellular Automata (CA). There were six main types of LULC classifications, i.e., ponds, built-up areas, mangroves, bare land, urban forests, and water areas. Furthermore, the map resulting from the land use simulation was used as the Manning Coefficients for tsunami simulation using the COMCOT model. The initial tsunami waves were generated based on the 2004 Indian Ocean Tsunami caused by 9.15 Mw earthquake. As a dynamic tsunami hazard approach, a sea-level rise of 0.35 m was considered for the next 50 years. The study results show the built-up area will be affected by the tsunami, about two-thirds of the city’s built area. Growth tends to occur in the southern part of the city outside the tsunami hazard zone. But there will also be the growth of built-up areas near the coast. Although much development is observed in the southern part of the city, the coastal area also needs attention because the sea level rise factor can exacerbate the impacts of tsunamis in the future.

KARAKTERISTIK EKOLOGI MANGROVE DI KAWASAN SILVOAKUAKULTUR

The development of mangrove by silvoaquaculture approach is an integrating between mangrove conservation and economic improvement of coastal communities by aquaculture production. The study aims to determine the ecological characteristics of mangroves in silvoaquaculture areas. The research locations include Karangsong, Brondong, and Pabean Ilir in Indramayu Regency and use a survey technique using the quadrant transect method. The silvoaquaculture pond area in Indramayu Regency has five types of mangroves, namely Avicennia marina, Avicennia alba, Rhizophora apiculata, Rhizophora mucronata, and Rhizophora stylosa. Rhizophora mucronata is the dominant mangrove species. The best mangrove ecological conditions are found in empang parit and komplangan ponds, so based on the ecological characteristics of mangroves, it is recommended that the development of silvoaquaculture ponds use empang parit or komplangan type of pond.

An overview of factors affecting salt gradient solar ponds

Among numerous types of Solar ponds, researchers and scientists have explored Salt Gradient Solar Ponds (SGSP) the most. These artificially constructed solar ponds are directly subjected to solar radiation; hence the temperature of the lower region of these ponds rises. This inside heat of the pond could be prevented by the convective heat transfer by making it a brine solution with the addition of some salts such as NaCl, MgCl2, NaNO3, etc. The present review contains the standard characteristics of solar desalination ponds. A summarized representation of the factors affecting the efficiency has been made by including effects of temperature, external heat addition, the effect of reflective covered surface, wall profile of the solar pond, and turbidity. Along with the increment in the efficiency, methods adopted to increase production of the freshwater, design, and economic viability are further covered in brief.

The influence of successional stage on local odonate communities in man-made standing waters

Man-made freshwater habitats are an important part of the European landscape, especially in areas with mostly absent or degraded natural habitats. To assess the role of different man-made standing waters in anthropogenic landscapes, we surveyed adult odonate communities in a cluster of 20 water bodies including fishponds and sandpit ponds in early and ongoing successional stages. We found 35 odonate species (i.e., 47% of the fauna of the Czech Republic), but their presence differed significantly among the three habitat types. The highest species diversity, driven mainly by the presence of generalists, was found in fishponds. Sandpit ponds in an early successional stage hosted the least diverse communities dominated by pioneer and vagrant species. Specialist species occurred in both types of sandpit ponds, especially those in an ongoing successional stage, more than in fishponds. Although the dragonfly biotic index did not differ among the three types of localities, all four species from the national Red list recorded during the study occurred only in sandpit ponds. The main environmental drivers of local odonate communities included the coverage of shoreline by emergent vegetation, water depth and bottom substrate; the latter two characteristics largely corresponded to the distinction between sandpit ponds and fishponds. We conclude that both sandpit ponds and fishponds play an important role in maintaining freshwater biodiversity that requires a mosaic of habitats in different successional stages.

Water mites (Hydrachnidia) of temporary ponds of Western Siberia: do the composition and the structure of acarofauna change over a long period of time?

Temporary ponds are specific freshwater habitats in which the characteristic fauna of aquatic organisms is formed. One of the large groups of invertebrates in temporary water bodies is water mites. In this work, water mites were studied in three different types of temporary ponds in the vicinity of the city of Tyumen, Western Siberia. The studies were carried out in two periods with a long time interval between them: in 2008–2010 and 2018–2019. In total, 33 species of water mites from 7 families were identified in the studied ponds. All ponds were dominated by vernal mite species typical for this type of water bodies. Also, they were characterized by similar seasonal dynamics of numbers. The species composition and the number of mites in different ponds varied, which is associated with different physicochemical parameters and the fauna of invertebrates, which served as food objects and hosts for the adults and larvae. Despite the small size and periodic drying of the ponds, the fauna of the mites inhabiting them has changed little over the long period of time that separates the studies. Only in one pond, which became permanent due to the rise of groundwater, significant changes in acarofauna were observed. Considering such constancy of the fauna of water mites of temporary ponds, they can be used as bioindicators of the ecological state of water bodies.

Pollution alters methanogenic and methanotrophic communities and increases dissolved methane in small ponds

Small ponds have become a hotspot of greenhouse gas emissions, but our understanding of methane (CH4) cycling and its biological regulation in small polluted ponds remains limited. To assess how pollution affects CH4 content, we investigated dissolved CH4 concentrations, water and sediments properties, methanogenic and methanotrophic communities in two types of small polluted ponds. Compared with low pollution (LP) ponds, high pollution (HP) ponds showed significantly (P < 0.05) higher dissolved CH4 in water. Sequencing of methyl coenzyme M reductase (mcrA) and particulate methane monooxygenase (pmoA) genes showed that HP led to significant (P < 0.05) shifts of CH4-cycling microbial communities, with increased Shannon index of sediment methanogenic communities and water methanotrophic communities. There were also strong negative associations (P < 0.05) between dissolved CH4 concentrations and interdomain methanogen-methanotroph network connectivity in water and sediments, respectively. The partial least squares path modeling indicated that dissolved oxygen, total organic carbon, ammonium nitrogen and nitrate nitrogen of water, and total nitrogen and total carbon of sediment, and CH4-cycling microbes could regulate the CH4 content. This study clarified the effects of environmental deterioration on CH4 cycling in small ponds, highlighting the use of methanogen-methanotroph network connectivity to assess the CH4 production.