Pond Environment Research Articles

Impact of the Slurry Pond of the Tyrnyauz Tungsten-Molybdenum Complex on the Mountain Territories Environment

The results of the Tyrnyauz tungsten-molybdenum Plant (TTMP) slurry pond settler environment impacts assessment are given in this scientific work, and the recommendations about the negative impact reduction on the environment are made. In the given work the characteristics of the environment state are investigated: atmospheric air, water objects and land resources.

Using Noble Gases to Compare Parameterizations of Air‐Water Gas Exchange and to Constrain Oxygen Losses by Ebullition in a Shallow Aquatic Environment

AbstractAccurate determination of air‐water gas exchange fluxes is critically important for calculating ecosystem metabolism rates from dissolved oxygen in shallow aquatic environments. We present a unique data set of the noble gases neon, argon, krypton, and xenon in a salt marsh pond to demonstrate how the dissolved noble gases can be used to quantify gas transfer processes and evaluate gas exchange parameterizations in shallow, near‐shore environments. These noble gases are sensitive to a variety of physical processes, including bubbling. We thus additionally use this data set to demonstrate how dissolved noble gases can be used to assess the contribution of bubbling from the sediments (ebullition) to gas fluxes. We find that while literature gas exchange parameterizations do well in modeling more soluble gases, ebullition must be accounted for in order to correctly calculate fluxes of the lighter noble gases. In particular, for neon and argon, the ebullition flux is larger than the differences in the diffusive gas exchange flux estimated by four different wind speed‐based parameterizations for gas exchange. We present an application of noble gas derived ebullition rates to improve estimates of oxygen metabolic fluxes in this shallow pond environment. Up to 21% of daily net oxygen production by photosynthesis may be lost from the pond via ebullition during some periods of biologically and physically produced supersaturation. Ebullition could be an important flux of oxygen and other gases that is measurable with noble gases in other shallow aquatic environments.

Biotic and abiotic factors influencing channel catfish egg and gut microbiome dynamics during early life stages

This study quantified the effects of pond rearing environments on microbial community composition in larval channel catfish (Ictalurus punctatus) gastrointestinal (GI) tracts across early developmental stages. Larvae were reared under standard industry conditions and sampled at five developmental stages (Egg, Swim-up, Day of stocking, 24 h post-stocking, and 21 d post-stocking). Massive-parallel sequencing of a segment of the 16S rRNA gene was conducted using an Illumina MiSeq platform to characterize the diversity and taxonomic composition of gut and water microbial communities. PERMANOVA analyses of differences in egg and gut microbial community composition across stages indicated a significant interaction between nursery pond environment, and family (P < 0.05) during the last two stages. Proteobacteria and Firmicutes genera along with genera including Vibrio, Aeromonas and Flavobacterium were associated with differences in gut bacterial community composition during larval development before and after pond stocking. Our study demonstrates that the aquatic rearing environment is an important factor influencing the transfer of microbes from water or food into the gut, and provides insight concerning the niche and ecological adaptability of microbes inside the channel catfish gut. Findings demonstrating that catfish gut community composition is highly variable over time indicates probiotic treatments may be possible, however gut community manipulation would require concurrent manipulation of pond or other environmental regimes and microbial communities.

Utilization of Wastewater from Vannamei Shrimp Pond for Rearing Milkfish in Keburuhan Coast Purworejo Sub-District

Brackish water vannamei shrimp in the village of Keburuhan, Ngombol District of Purworejo Regency is one of the shrimp aquaculture activities developed since 2010. Shrimp farming enteprises is done by local communities which use the sandy soil coated plastic sheet with an area of 1000-4500 m 2 . There is a positive impact by increasing the income and welfare of farmers, but give negative effects in decline of surrounding pond environment. The shrimp farmers mostly disposed of wastewater directly into the sewers or the surrounding area. The wastewater of vannamei shrimp culture contains of uneaten feed and plankton that can be utilized to grow milkfish. The aim of this study was to determine the growth and feeding preferences for milkfish culture in wastewater reservoir of vannamei culture. The study was conducted from January to April 2017 by rearing of milkfish in earthen ponds of shrimp culture in wastewater reservoir. Wastes consist of feces and uneaten feed during shrimp rearing were siphoned and flowed into ponds wastewater reservoir. Milkfish juvenile with body length ranges from 9.3 to 9.7 cm and weight ranges from 3.4 to 6.9 g was introduced into three earthen ponds of 600 m 2 each, with density of 6 individual/m 2 in triplicate for 70 days. During the study, milkfish juvenile were not fed, but obtained wastewater from shrimp culture ponds. The wastewater from the shrimp ponds was siphoned and piped into a waste reservoir ponds every 3 days until shrimp harvesting. Fish samples of each pond as much as 40 individuals were taken biweekly and then measured the length and weight. Fish stomach was dissected and then digestive tract was taken to observe the species of plankton consumed. The results showed that milkfish could grow well in wastewater reservoir of shrimp culture. The average daily growth rate of length and weight of milkfish reached approximately 0.11 cm/day and 0.34 g/day, respectively. The length weight relationship of milkfish showed allometric growth pattern. The food type found in the intestinal was dominated by phytoplankton. Feed was dominated by genera of phytoplankton, which reach more than 99%. The most dominant of phytoplankton were Scenedesmus sp. (34.7%), then Crucigenia sp. (20.1%), followed by Cyclotella sp. (14.6%), and Clamydomonas sp. (7.5%) next Microcystis sp. (6.7%), while the other genera less than 4.2%. Further research is needed to determine the optimum density of milkfish to utilize wastewater of shrimp culture.

Adaptability and growth performance of Avicennia marina seedling within Silvofishery pond

The application of silvofishery pond raised the question on the suitability of particular mangrove species to be integrated. This research aimed to study the survival and growth rate of Avicennia marina seedling within silvofishery pond, to analyze its growth performance compared to its natural habitat and to determine the appropriateness of A. marina plantation in the silvofishery pond. Experiment was designed to apply variation of mangrove composition, including pure (monoculture) and mixed (polyculture) mangrove species. The experiment was conducted for a year involving 5 observations periods to 27 expected samples with 3 months interval. Data collection was conducted to seedling survival, height and diameter. The result showed low survival of A. marina during the research. Survival of A. marina in pure (monoculture) treatment was fluctuated among periods with the ranged of 1 – 7 stands, while in the mixed (polyculture) treatment was ranged from 1 – 3 stands. Average height growth was higher in the pure (monoculture) treatment with 41.94 mm.month-1, 96.43 mm/month, 95.60 mm/month and 39.56 mm/month compared to 41.94 mm/month, 50.55 mm/month, 41.21 mm/month and 37.91 mm/month in the mixed (polyculture) treatment respectively for the first, second, third and forth periods. While the diameter growth was fluctuated. This result indicated better growth performance compared to previous researches. This research concluded that mangrove silvofishery pond environment is not suitable for the establishment of A. marina, even though it might provide a good growth performance. But, this species is not recommended for plantation in the pond due to its low survival which inhibit ecosystem establishment and expected environmental services.

Potential Re-utilization of Composted Mangrove Litters for Pond Environment Quality Improvement

Production of mangrove litter from pruning and thinning activities is potential source of organic materials which could be re-utilized to improve pond environment quality and fertility. This research aimed to analyze the nutrient composition compost produced from mangrove litter and to describe the effect of compost application on pond quality. This research was conducted through two phases, including composting trial and application of compost on pond trial. Composting process was conducted for 45-60 days on mangrove litter achieved from pruning activities in the silvofishery pond using composting container, while application of compost in pond was conducted by pouring 2 kg of compost in 25 m2 pond. Production of compost included solid compost and liquid compost. Nutrient concentration of solid compost was ranged from 0.47-0.52% for N; 0.36-0.44% for P; and 5.45-6.39% for organic C, while liquid compost provided 0.62-0.69%; 0.24-0.32%; and 3.98-4.45% respectively for N, P and organic C. While C/N ratio was ranged from 11.60-12.78 and 5.77-7.18 respectively for solid and liquid compost. Solid compost quality resulted that N, P and C/N ration had fulfilled the standart criteria defined by Indonesia National Standart for compost. Observed impact of compost application on pond water quality were the improvement of water clarity and increasing abundance of klekap (lab-lab). This showed that mangrove litters could be converted into a more productive materials to enhance pond environment quality and productivity, decrease management cost and increase benefit. Scheduled fertilization with compost is suggested to be conducted to provide best benefit on silvofishery management.

Variations in piscivory of invasive largemouth bass Micropterus salmoides associated with pond environments

Introductions of non-native predatory fishes can be a major driver of aquatic biodiversity loss. The largemouth bass Micropterus salmoides (L.) has been introduced throughout much of the world, thereafter negatively affecting native faunal communities owing to its predatory impact. To investigate the environmental factors affecting the predatory performance of invasive bass, we examined the stomach contents and habitat characteristics of bass in 15 irrigation farm ponds in northeastern Japan. The food habits of the bass populations differed among the studied ponds: the predominant prey items were fishes among bass in seven of the ponds, whereas aquatic invertebrates (mainly insects and zooplankton) were the predominant taxa in the diets of bass in the eight remaining ponds, with the onset of piscivory related to body size. The results of multivariate analysis indicated that the extent to which the bass consumed fish was positively associated with fish prey abundance and negatively associated with percentage of aquatic vegetation coverage. We suggest that the extent of aquatic vegetation coverage strongly influenced the predation efficiency of bass in the ponds. These findings might be employed to assess a pond ecosystem’s vulnerability to invasive largemouth bass and to reduce the predator’s impact on native fish species by improvements to the habitat.

Noisy Neighbors: Acoustic Interference and Vocal Interactions between Two Syntopic Species of Ranid Frogs, Rana clamitans and Rana catesbeiana

Abstract American Bullfrogs (Rana catesbeiana) and Green Frogs (Rana clamitans) share ranges and breeding seasons, are ecologically similar, and often occupy the same breeding ponds throughout the summer. Males of both species use vocalizations to defend territories and attract females; however, Bullfrogs have longer calls and call much more frequently than Green Frogs. The calls of the two species overlap in frequency; thus, Bullfrog calls are a likely source of acoustic interference for Green Frogs that could affect their ability to attract females. Nevertheless, in natural settings where these species co-occur, Green Frogs reproduce successfully. This suggests that Green Frogs respond to the calling patterns of Bullfrogs in ways that maximize Green Frog signal-to-noise ratio. We used long-term pond environment recordings and bioacoustics analyzing software to explore the influence of Bullfrog calling patterns on the vocal activity of syntopic Green Frogs. We found both species call most actively within...

A Review of the Factors That Determine Whether Stormwater Ponds Are Ecological Traps And/or High-Quality Breeding Sites for Amphibians

Stormwater ponds were originally constructed to control the quantity and quality of runoff on urban roads and highways before it was released to the environment. Often, stormwater ponds were designed in a technical feat of civil engineering, with no particular ecological or landscape objective in mind. Nevertheless, they are colonized spontaneously by diverse species, including amphibians. Through an initial review of the scientific literature, the objective of this study was to understand which factors determine that a pond can be considered as an ecological trap or a valuable breeding site fort amphibian. The first step was to question the role of the pond environment as a major factor in its colonization by amphibians, demonstrating that not all ponds are colonized by the same variety of species. The internal factors in the ponds that define them as ecological traps or sustainable breeding sites for amphibians was also considered. After confirming the functional and structural similarity between highway and urban stormwater ponds, 25 publications were compared, with study sites mostly located in Europe and North America, and concerning the colonization of stormwater ponds by amphibians in urban or highway areas. Several factors were identified that may affect the ecological viability of these basins: 1) the factors related to the shape of the ponds (inclination of the banks, materials used, etc.); 2) the biotic factors (aquatic vegetation, presence of predators, etc.); 3) the abiotic factors (luminosity, water level in the ponds, etc.); and 4) pollutants. The low number of publications on this subject, as well as the law variety in the location of study sites, only allows for cautious conclusions be drawn. In particular, stormwater ponds located in highly anthropogenic landscapes can be both ecological traps and suitable habitats for amphibian breeding. This depends on the species that colonize each pond, many internal factors, and the environmental context in which it is embedded. Additional research is therefore needed in other parts of the world - particularly in amphibian biodiversity hotspots - as well as other impact factors such as the effects of different maintenance practices.

Morphological diversification of ampullariid gastropods (Nsungwe Formation, Late Oligocene, Rukwa Rift Basin, Tanzania) is coincident with onset of East African rifting

AbstractA new freshwater gastropod fauna is described from the late Oligocene Nsungwe Formation of the Rukwa Rift Basin, Tanzania. Six new species of ampullariids are established including five species of Lanistes (L. microovum, L. nsungwensis, L. rukwaensis, L. songwellipticus and L. songweovum) and one species of Carnevalea (C. santiapillaii). These taxa occupy a morphospace region comparable to nearly half of extant Lanistes, a common and widespread genus in Africa and Madagascar. Palaeoecological evidence indicates that Nsungwe ampullariids inhabited fluvial, pond and paludal environments. Among these species are the oldest high‐spired and fluvially adapated Lanistes taxa. We suggest that Nsungwe Lanistes rapidly diversified in concert with habitat heterogeneity associated with the initiation of rifting along the western branch of the East African Rift System (EARS). Taxonomy, evolution and the biogeographical affinities of Nsungwe Formation freshwater gastropods contributes significantly to expanding the undersampled Palaeogene invertebrate fossil record of continental Africa.

Environmental Quality of Shrimp Ponds in The Coastal Region Of Brebes Regency

The largest utilization of coastal areas in Brebes Regency is the shrimp farming ponds. Shrimp volume statistics until 2016 showed that shrimp production in Brebes tends to decrease. The decrease in shrimp production can be caused by disruption in the environmental quality from the surrounding activities. This study aims to analyze the causes of declining production based on the quality of the physical environment of shrimp ponds. The variables used are water quality values (Ph, Tds / Ec, and salino), vegetation values of ponds, and waste disposal values around ponds &lt;1000m, 1000-2000m,&gt; 2000m. The data used is a Quick Bird image as of 2015 to determine the area of shrimp ponds and results of field survey in February 2018 for water quality sampling and observation. The analytical method that is used is scoring and weighting. The grades of pond environment quality that are produced are Poor; Good; and Well. The results show that the subdistricts of Brebes and Wanasari have well environmental quality; Tanjung has good environmental quality; and environmental value of Bulakamba and Losari subdistricts have poor environmental quality. Environmental quality is strongly influenced by industrial activities, onion farming activities, and settlements. This environmental quality study can be utilized for the management of sustainable shrimp farming.

Persistence of DNA on clothes after exposure to water for different time periods-a study on bathtub, pond, and river.

DNA traces on clothes of drowned bodies can provide important evidence for police investigations, especially in cases of suspected suicides or homicides. However, it is generally assumed that the water "erodes" a large part of the DNA depending especially on the exposure time. In forensic casework, DNA of suspects could be found frequently on clothes of drowned bodies after hours, sometimes days of exposure to water. This study was conducted to attempt a general statement about the conditions under which sufficient DNA remains can be expected for molecular genetic analysis. For this purpose, different scenarios were designed including DNA from three to five people, different types of waters (tap, pond, bathtub and river) for various time periods, with higher water pressure, different temperature, and soapy water (bathtub). Epithelial cells and blood cells were mounted on cotton cloths, and the DNA left after exposure was analyzed using the Powerplex® ESX17fast kit. In the indoor experiments, complete profiles could be seen even after 10min rinsing of clothes under the tap and after 1week in the bathtub. Outdoors, the results differed considerably between summer and winter as well as between pond and river. The longest exposure time still resulting in a complete profile was 2weeks for a sample with skin cells in the pond during winter. In summer, the time period for erasing the bulk of DNA was 4hours regarding epithelial samples and more than 1day for blood samples in pond and river environments. All in all, the results demonstrate that DNA could still be recovered from clothes exposed to water for more than 1week.

Risk of acidification of the organic shrimp model at Tam Giang commune, Nam Can district, Ca Mau province

This paper assesses the risk of acidification of the organic shrimp model certified by Naturland at Tam Giang commune, Nam Can district, Camau province. Pond water and sediment was sampled in 8 ponds in March, July and November 2015, dike soil and mangrove soils were sampled in March 2015. Pond sediment and mangrove soils are highly reduced (Eh of top sediment and soils to 60 cm depth range respectively from -299 – -1mV and -321 – -52mV). Pond water ranges from neutral to slightly alkaline (pH of pond water 7.01-8.82) and sediment from slightly acidic to slightly alkaline (pH of fresh sediment 6.05-7.64, pHH2O 6.63-7.78, pHKCl 6.35-7.43). Mangrove soils show a large pH range with very low minimums (pHH2O 3.72, pHKCl 3.05), reconfirming the presence of pyrite mineral in the soil profile. Mangrove soils deposited on the dikes (partly oxidized) are very acidic (pHH2O 2.51±0.72, pHKCl 1.81-2.14, exchange acidity 11.56±2.69 meq/100g). At the start of the wet season, pH of pond water reduces sharply as a result of reception of acidic components from the oxidized pyritic material (FeS2) on the dikes. The exchange acidity in pond sediment and mangrove soils are negatively correlated with organic matter, indicating that the decomposition of organic matter under reduced conditions contributes to exchange acidity in pond environment. Risk of acidification of the organic shrimp model is high due to managerial activities (mostly channel digging and disposal of pyrite-containing mangrove soils on the dikes).

Efficacy of potential phage cocktails against Vibrio harveyi and closely related Vibrio species isolated from shrimp aquaculture environment in the south east coast of India

A diverse set of novel phages infecting the marine pathogenic Vibrio harveyi was isolated from shrimp aquaculture environments in the south east coast of India. Based on initial screening, three phages with a broad host range revealed that the growth inhibition of phage is relatively specific to V. harveyi. They were also able to infect V. alginolyticus and V. parahemolyticus that belonged to the Harveyi clade species from shrimp pond and sea coast environment samples. However, the impact of these phages on their host bacterium are well understood; a one-step growth curve experiment and transmission electron microscope (TEM) revealed three phages grouped under the Myoviridae (VHM1 and VHM2); Siphoviridae (VHS1) family. These phages were further molecular characterized with respect to phage genomic DNA isolates. The randomly amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) digestion with HindIII, and major structural proteins were distinguished by sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) clearly indicated that all the phage isolates were different, even when they came from the same source, giving an insight into the diversity of phages. Evaluation of microcosm studies of Penaeus monodon larvae infected with V. harveyi (105 CFU mL−1) showed that larvae survival after 96 h in the presence of phage treatment at 109 PFU mL−1 was enhanced when compared with the control. The resolution in over survival highly recommended that this study provides the phage-based therapy which could be an innovative and eco-friendly solution against Vibrio disease in shrimp aquaculture and in the natural environment.

Habitat age influences metacommunity assembly and species richness in successional pond ecosystems

AbstractMetacommunity theory suggests that species diversity can depend upon the time since initiation of community assembly, or habitat age, as the relative influence of regional and local structuring processes changes over succession. There are, however, few studies that evaluate the role of habitat age in structuring species richness (diversity–age) over large, fine‐resolution age gradients of secondary succession in metacommunities. To test theoretical predictions of diversity–age relationships in metacommunities, zooplankton species richness and composition along a successional chronosequence in beaver (Castor canadensis) ponds were evaluated. The age of ponds was determined using dendrochronology and historical photography, and ranged from 23 to 69 yr of age. A unimodal relationship between zooplankton species richness and habitat age was observed among the successional ecosystems. This hump‐shaped relationship with community assembly time is congruent with theoretical predictions of species richness in metacommunities and can be explained by the increasing importance of local, relative to regional, structuring processes over successional trajectories. Observed patterns of diversity and composition responded to age‐mediated effects on the local pond environment; older ponds were deeper, had lower colored dissolved organic carbon, and were permanent. Additionally, there were weak but significant dispersal effects on community composition across the region. The lack of consistent community composition by successional stage reflected variation from differences in pond nutrient availability and species dispersal. The results indicate that regional and local age‐dependent structuring mechanisms operate at each successional stage on different local colonist pools and environments yielding communities that reflect succession in their richness response. Consequently, secondary succession should be considered an influential driver of species diversity across temporal and spatial scales in metacommunities.

Characterization of the stress corrosion cracking behavior of thermally sensitized 20Cr-25Ni stainless steel in a simulated cooling pond environment

ABSTRACTNiobium stabilized 20Cr-25Ni stainless steel is used for nuclear fuel cladding in the UK's fleet of advanced gas cooled reactors (AGRs). The cladding can have chromium-depleted grain boundaries as a consequence of irradiation in a reactor core, rendering a small proportion of cladding susceptible to intergranular stress corrosion cracking in cooling pond waters after removal from the reactor. In this work, thermal sensitization was used to simulate chromium depletion and the sensitized material was assessed for its susceptibility to pitting corrosion and stress corrosion cracking using slow strain rate testing (SSRT). Elevated chloride concentrations were used to accelerate corrosion initiation and propagation. In 10 ppm chloride and 80 °C, the pitting potential was at potentials between +375 mV and +400 mV (SCE). SSRT appeared to lower the pitting potential, with intergranular corrosion and intergranular stress corrosion cracks observed to nucleate at potentials of +200 mV (SCE).

ANALISIS KETAHANAN KOROSI PIPA A53 PADA LINGUNGAN OIL SLUDGE DENGAN METODE C-RING

Corrosion is the degradation of the material surface due to reaction with the environment. Steel pipe is one of the materials vulnerable to corrosion because the piping system is always in contact with the outside environment. This research have a purpose to know influence of cold working about corrosion resistance pipe A53 on oil sludge salt water and oil sludge pond environment with c-ring method. Oil sludge is sediment of crude oil thats contain water, sediment, and oil thats can be processed again. The cold working process is carried out by providing bending loads of 114 kg, 140 kg, and 160 kg, and one material without bending. Process of corrosion testing uses weight loss method by weighing the material before it is corroded and after corrosion. Result of test showed that there was an increase of hardness on the material with bending load of 114 kg, 140 kg, and 160 kg respectively of 103.33 BHN, 134.00 BHN, and 187.66 BHN, while the material without bending had a hardness of 93.33 BHN. Corrosion rate on material without bending with oil sludge salt water is 2,12 x 10-2 mmpy while in oil sludge pond equal to 1,67 x 10-2 mmpy. Materials with bending loads of 114 kg, 140 kg, and 160 kg have a corrosion rate of 2.35 x 10-2 mmpy, 2.88 x 10- 2 mmpy, and 4.18 x 10-2 mmpy on oil sludge salt water, and 1.19 x10-2 mmpy, 2.15 x 10-2 mmpy, and 3.09 x 10-2 mmpy on oil sludge pond. Oil sludge of salt water is more reactive than oil sludge pond because it contains sea water composed of NaCl compounds which is a corrosive environment .The given bending load results in strain hardening followed by increased energy on the material so that the corrosion rate increases. Cold treatment provided resulted in cracks on the surface of the material so that the corrosion was localized to the crack and formed pitting.&#x0D; Keywords : A53, Oil Sludge, Strain Hardening, Weight Loss

Wetland evolution in the Qinghai Lake area, China, in response to hydrodynamic and eolian processes during the past 1100 years

The Daotanghe riverine wetland in close proximity to the Qinghai Lake was investigated to demonstrate the interrelationships between Qinghai Lake hydrodynamic processes, eolian mobility and ecological conditions during the past 1100 years in response to climate change. We used ostracod assemblages from various sites east of Qinghai Lake and from the sediment core QW15 of Daotanghe Pond and combined them with grain size and geochemical data from the same core. The statistical extraction of grain size endmembers (EM) revealed three different transportation processes responsible for pond-related fluvio-lacustrine, pure fluvial and eolian deposits. Identified seasonal effects (eolian mobility phase) and timing of ice cover are possible tracers for the competing influence between the Asian summer monsoon and the Westerlies in the Daotanghe Wetland and surrounding area.Our results show that ostracod associations and sediment properties are evidence of a fluvio-lacustrine fresh water environment without ingression of Qinghai Lake into the wetland. Hydrodynamic variations coupled with phases of eolian input indicate highly variable water budgets in response to climate-induced effective moisture supply. The Medieval Warm Period (MWP) until about 1270 CE displays generally moist and warm climate conditions with minor fluctuations, likely in response to variations in summer monsoon intensity. The three-partite period of the Little Ice Age (LIA), shows hydrologically unstable conditions between 1350 and 1530 CE with remarkably colder periods, assigned to a prolonged seasonal ice cover. Pond desiccation and replacement by fluvial deposits occurred between 1530 and 1750 CE, superimposed by eolian deposits. The phase 1730–1900 CE is recorded by the re-occurrence of a pond environment with reduced eolian input. Principal Component Analysis (PCA) on ostracod abundances shows similar trends. All three phases of the LIA developed during a weak summer monsoon influence, favoring westerly-derived climate conditions until ca. 1850 CE, in accordance with records from the adjacent regions.Seasonal freezing periods in excess of the average time of frozen water bodies also occurred in periods of the well-known grand solar minima and indicate stronger seasonality, possibly independent from variations in summer monsoon strength but with links to global northern hemispheric climate.

Paleohydrology and paleoenvironments at Bir Sahara: Pleistocene lithostratigraphy and sedimentology in the southern Egyptian Sahara

The Bir Sahara area contains a remarkable record of Middle and Late Pleistocene hydrologic and environmental conditions for Saharan North Africa, based on lithostratigraphic and sedimentologic evidence from basin-fill deposits. Some of the deposits contain Lower Paleolithic (Acheulean) or Middle Paleolithic artifacts that help to constrain their age, since Acheulian artifacts are assigned to the Middle Pleistocene, while Middle Paleolithic artifacts are limited to either the Middle or Late Pleistocene. Locality BS-14 is in the southern part of Bir Sahara, while localities E-88-15, E-88-2, BS-13, and BS-16 are situated in the south-central part of the deflational basin, closer to the present-day water-hole. Lowered groundwater conditions during arid intervals resulted in erosional topographic basins. These deflational basins were later filled with sediments associated with wetter hydrologic conditions. The oldest studied sedimentary sequence in the Bir Sahara depression (BS-14) contains in situ Acheulian artifacts. Acheulian handaxes are found in sands underlying carbonates that are interpreted as evidence of spring-fed pond and marsh environments during a Middle Pleistocene wet interval. At the E-88-15 locality, the stratigraphic sequence documents deposition in a possible perennial pond or small lake that varied in extent and depth and is associated with Middle Paleolithic artifacts. At E-88-12 and BS-13, lateral and vertical variations in the lithofacies of the basin-fill sediments provide additional records of changing hydrologic conditions during the Late Pleistocene. These hydrologic conditions appear to reflect variations in water-table levels related to groundwater recharge and, at times, local rains.

An Expert-Based Assessment Model for Evaluating Habitat Suitability of Pond-Breeding Amphibians

Farm ponds are important habitats for amphibians, birds, and other wildlife. In Taiwan, artificial ponds were originally created on farmlands for irrigation purposes and the needs of the domestic water supply. Although pond creation is a typical farming practice, it also provides habitats for pond-breeding amphibians. Thus, it is essential to understand the current status of habitats and their vulnerability regarding urgent conservation needs for target species. Günther’s frog (Hylarana guentheri), a pond-breeding amphibian, has a high sensitivity towards surrounding environmental changes, and can be used as an indicator species to assess habitat suitability. The purpose of this study is to establish a systematic framework to assess the habitat suitability of pond-breeding amphibians by using Günther’s frog as a pilot-study species. First, we collected frog survey data from Chiayi, Taiwan, from winter 2013 to spring 2015, and investigated the present status of the environmental conditions around the ponds. Next, expert questionnaires and the fuzzy Delphi method were applied to establish the hierarchical evaluation criteria regarding the habitat suitability assessment. Four indicators: the aquatic environments of farm ponds; the terrestrial environments around ponds; landscape connectivity; and the conservation perceptions of the residents, were determined as first-layer factors in the assessment criteria, while ten other indicators were defined as second-layer factors. Based on the established assessment criteria, we performed in situ habitat suitability evaluations on 69 selected sites and surveyed the perceptions of the residents using questionnaires. Results revealed that 19% of locations were rich in frog species with a high habitat suitability. However, 67% of locations showed signs of habitat degradation, which may imply a higher need in practicing habitat improvement or restoration. The Kappa value was 0.6061, which indicated a high reliability of the habitat suitability assessment model. In brief, the proposed method can be applied, not only to assess the sustainability of frog habitats and degradation risks, but also to determine which locations may require future attention regarding conservation implementation. Furthermore, findings in this study provide useful background knowledge to all associated stakeholders when designing and implementing plans of wildlife habitat management and restoration at farm ponds.