Observations on the habitat and biology of a lymnaeid snail, Austropeplea vinosa (Gastropoda : Pulmonata), an intermediate host for avian schistosomes in tropical Austarlia

The aquatic snail A. vinosa is widely distributed in northern Queensland, occurring in rivers and in static waters, both semipermanent and permanent. The snail is capable of breeding throughout the year. although fewer small snails are present during the cooler months. Rainfall rather than temperature appears to be the main factor influencing populations of A. vinosa, very small snails being able to survive drought by aestivating in the mud. Heavy summer rains refill temporary habitats, and small snails emerge to recommence growth. The same summer rains flood permanent habitats and can wash away snail populations living there. Infection levels of larval flukes in A. vinosa are generally lowest in the wet season and rise as the dry season progresses. The effects of wet season floods and steadily diminishing water levels during the dry season are thought to account for this. The risk of human bathers contracting schistosome dermatitis is therefore highest in the early summer, towards the end of the dry season, when the larvae of avian schistomes are most abundant.

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Epidemiological studies of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v73i3.144 ◽

2006 ◽

Vol 73 (3) ◽

Author(s):

D.M. Pfukenyi ◽

S. Mukaratirwa ◽

A.L. Willingham ◽

J. Monrad

Keyword(s):

Intermediate Host ◽

Climatic Factors ◽

Seasonal Pattern ◽

Chemical Properties ◽

Dry Season ◽

Wet Season ◽

Adult Cattle ◽

Host Snail ◽

Faecal Samples ◽

Hot Dry Season

During the period between January 1999 and December 2000, the distribution and seasonal patterns of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Faecal samples of cattle were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of the intermediate host-snail populations and the climatic factors influencing the distribution were also determined at monthly intervals from November 1998 to October 2000, a period of 24 months, in six dams and six streams in the highveld and nine dams in the lowveld communal grazing areas. Monthly, each site was sampled for relative snail density, the vegetation cover and type, and physical and chemical properties of the water. Mean monthly rainfall and temperature were recorded. Snails collected at the same time were individually examined for shedding of cercariae of S. mattheei and Schistosoma haematobium. A total of 16 264 (5 418 calves, 5 461 weaners and 5 385 adults) faecal samples were collected during the entire period of study and 734 (4.5 %) were positive for S. mattheei eggs. Significantly higher prevalences were found in the highveld compared to the lowveld (P < 0.001), calves compared to adult cattle (P < 0.01) and the wet season compared to the dry season (P < 0.01). Faecal egg output peaked from October/ November to March / April for both years of the study. Bulinus globosus, the snail intermediate host of S. mattheei was recorded from the study sites with the highveld having a significantly higher abundance of the snails than the lowveld (P < 0.01). Monthly densities of B. globosus did not show a clearcut pattern although there were peaks between March / May and September / November. The mean num ber of snails collected was positively correlated with the water plants Nymphaea caerulea and Typha species. Overall, 2.5 % of B. globosus were shedding Schistosoma cercariae. In the highveld, 2.8 % of B. globosus were infected with schistosome cercariae and 1.5 % in the lowveld, with the figures at individual sites ranging from 0-18.8 % in the highveld and from 0-4.5 % in the lowveld. The cercariae recorded here were a mixture of S. mattheei and S. haematobium since they share the same intermediate host. The transmission of Schistosoma cercariae exhibited a marked seasonal pattern, being more intensive during the hot, dry season (September / November).

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Soil water storage and groundwater behaviour in a catenary sequence beneath forest in central Amazonia. II. Floodplain water table behaviour and implications for streamflow generation

Hydrology and Earth System Sciences ◽

10.5194/hess-1-279-1997 ◽

1997 ◽

Vol 1 (2) ◽

pp. 279-290 ◽

Cited By ~ 27

Author(s):

M. G. Hodnett ◽

I. Vendrame ◽

A. De O. Marques Filho ◽

M. D. Oyama ◽

J. Tomasella

Keyword(s):

Soil Water ◽

Water Table ◽

Dry Season ◽

Water Levels ◽

Soil Water Storage ◽

Published Data ◽

Wet Season ◽

Deep Drainage ◽

Forested Catchments ◽

Streamflow Generation

Abstract. Valley floor groundwater level data collected during the ABRACOS project (Gash et al. 1996), and published streamflow data from small forested catchments in geomorphologically similar areas nearby have been analysed to improve the understanding of the processes of streamflow generation. Early in the wet season, the floodplain water table is typically at 0.8 m depth, or less, and receives only local, vertical recharge. Large storms may create a groundwater ridge beneath the floodplain, temporarily creating a gradient in the direction of the hilislope. Later in the wet season, floodplain water levels are controlled primarily by the discharge of groundwater which maintains the dry season streamflow. The groundwater is recharged by deep drainage from beneath the plateau and slope areas once the dry season soil water deficit has been overcome. In the late wet season, the water level is almost at the floodplain surface and may create seeps on the lower slopes in very wet years. For the period 1966-1989, the recharge was estimated to range from 290 mm to 1601 mm with a mean of 1087 mm. Published data show that baseflow is 91% of annual runoff. Stormflow is generated on the floodplain, and water table recessions after rainfall events show that the runoff response depends on the depth to the water table. These results are from areas with deeply weathered and permeable soils; in areas of Amazonia with shallower soils, the predominant flow generation processes will differ (Elsenbeer and Lack, 1996).

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River Discharge and Water Level Changes in the Mekong River: Droughts in an Era of Mega-Dams

10.22541/au.161189206.60684509/v1 ◽

2021 ◽

Author(s):

XiXi Lu ◽

Samuel Chua

Keyword(s):

Water Level ◽

Water Discharge ◽

Dry Season ◽

Water Levels ◽

Mekong River ◽

Wet Season ◽

Discharge Data ◽

Mekong Basin ◽

Lower Mekong Basin ◽

Dry Conditions

While 1992 marked the first major dam – Manwan – on the main stem of the Mekong River, the post-2010 era has seen the construction and operationalisation of mega dams such as Xiaowan (started operations in 2010) and Nuozhadu (started operations in 2014) that were much larger than any dams built before. The scale of these projects implies that their operations will likely have significant ecological and hydrological impacts from the Upper Mekong Basin to the Vietnamese Delta and beyond. Historical water level and water discharge data from 1960 to 2020 were analysed to examine the changes to streamflow conditions across three time periods: 1960-1991 (pre-dam), 1992-2009 (growth) and 2010-2020 (mega-dam). At Chiang Saen, the nearest station to the China border, monthly water discharge in the mega-dam period has increased by up to 98% during the dry season and decreased up as much as -35% during the wet season when compared to pre-dam records. Similarly, monthly water levels also rose by up to +1.16m during the dry season and dropped by up to -1.55m during the wet season. This pattern of hydrological alterations is observed further downstream to at least Stung Treng (Cambodia) in our study, showing that Mekong streamflow characteristics have shifted substantially in the post-2010 era. In light of such changes, the 2019-2020 drought – the most severe one in the recent history in the Lower Mekong Basin – was a consequent of constructed dams reducing the amount of water during the wet season. This reduction of water was exacerbated by the decreased monsoon precipitation in 2019. Concurrently, the untimely operationalisation of the newly opened Xayaburi dam in Laos coincided with the peak of the 2019-2020 drought and could have aggravated the dry conditions downstream. Thus, the mega-dam era (post-2010) may signal the start of a new normal of wet-season droughts.

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Spatial and Temporal Water Quality Evaluation of Heavy Metals of Habbaniyah Lake, Iraq

International Journal of Design & Nature and Ecodynamics ◽

10.18280/ijdne.160414 ◽

2021 ◽

Vol 16 (4) ◽

pp. 467-475

Author(s):

Huda Sulaiman Ghalib ◽

Majeed Mattar Ramal

Keyword(s):

Heavy Metals ◽

Water Quality ◽

Heavy Metal ◽

Principal Component ◽

Dry Season ◽

Point Sources ◽

Pollution Sources ◽

Water Levels ◽

Anthropogenic Sources ◽

Wet Season

Heavy metal concentrations in a water sample from Habbaniyah Lake (HL), Iraq (Cr, Cd, Ni, Fe, Co, Zn, Pb, and Cu). Thirty-three sites were chosen in the research area from October 2020 to April 2021 to evaluate emissions of heavy metals during two seasons (dry and wet). Spectrophotometer for atomic absorption was used to test heavy metal concentration (USA Phoenix-986). The findings of the study indicate that water levels were concentrated Cr>Ni >Fe>Co>Pb>Zn=Cd=Cu during the dry season and the wet season Cr>Fe>Pb>Co>Ni=Zn=Cd=Cu. HMPI and HMEI were both used to assess the level of water supply toxicity of heavy metals in the area of research. In Habbaniyah Lake water, several concentrations of heavy metals exceed the criteria for drinking and water life such as Co and Pb were exceed the allowed limits of WHO, CCME in the dry and wet seasons. The study area's human, agricultural and industrial activities and human population resulted in a rise in heavy element concentrations including Cr that surpassed the WHO, CCME, FAO, EPA, and IQS. The mean values of (Cd, Zn, and Cu) during dry and wet seasons were non-consistent in all stations. The average value of Ni was above water life limit during the dry season. The average values of CD, HMPI, and HMEI during the wet season were 20.8984, 57.8248 and 24.8977 and in the dry season were 17.3745, 61.8769, and 22.3747 respectively. Results indicate that HL is highly contaminated with HMs according to national and international guidelines, (CD), (HMPI) and (HMEI) indices pointed that HL water quality was bad. Principal component analysis (PCA) and cluster analysis (CA) were applied to estimate the pollution sources, results show that, pollution are originated from multiple sources, anthropogenic sources are major pollution sources while lithogenic is minor pollution sources, anthropogenic origin, which is mostly due to the wastewater point sources on Warrar stream.

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Water levels affect photosynthesis and nutrient use more than salinity in a scrub Red Mangrove forest of the southeastern Florida Everglades

10.1101/2021.01.27.428494 ◽

2021 ◽

Author(s):

J. Aaron Hogan ◽

Edward Castañeda-Moya ◽

Lukas Lamb-Wotton ◽

Christopher Baraloto

Keyword(s):

Water Level ◽

Mangrove Forest ◽

Leaf Gas Exchange ◽

Critical Role ◽

Dry Season ◽

Water Levels ◽

Marginal Effect ◽

Mangrove Forests ◽

Wet Season ◽

Porewater Salinity

AbstractPhotosynthesis is an essential process to mangrove forest carbon cycling, which plays a critical role in the global carbon cycle. We investigated how differences in mangrove island micro-elevation (i.e., habitat) affect tree physiology in a scrub mangrove forests of the southeastern Everglades. We measured leaf gas exchange rates of scrub Rhizophora mangle trees monthly during 2019, hypothesizing that CO2 assimilation (Anet) and stomatal conductance (gsw) would decline with increases in water level and salinity, with larger differences at mangrove islands edges than centers, where inundation and salt stress are greatest. Water levels varied between 0 and 60 cm, rising during the wet season (May-October) relative to the dry season (November-April). Porewater salinity ranged from 15 to 30 ppt, being higher at mangrove island edges compared to centers. Anet maximized at 15.1 µmol m-2 s-1, and gsw was typically <0.2 mol m-2 s-1, both of which were greater in the dry than the wet season and greater at mangrove island centers than edges. After accounting for season and habitat, water level had a positive effect on Anet in both seasons, but no effect on gsw. Similarly, porewater salinity had a slightly positive marginal effect on Anet but a negligible effect on gsw Our findings suggest that water levels drive variation in Anet more than salinity in Everglades scrub mangroves, while also constraining Anet more than gsw, and that the interaction between permanent flooding and habitat varies with season as physiological stress is alleviated at higher-elevation mangrove island center habitats in the dry season. Additionally, habitat heterogeneity leads to differences in nutrient and water acquisition and use between trees growing in island centers versus edges, creating distinct physiological controls on leaf physiology and photosynthesis which could ultimately affect carbon flux dynamics of scrub mangrove forests across the Everglades landscape.

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Spatial and temporal variations of hydrodynamics and sediment dynamics in Indus River Estuary,Pakistan

Global NEST Journal ◽

10.30955/gnj.003333 ◽

2021 ◽

Keyword(s):

Sediment Transport ◽

River Discharge ◽

Saltwater Intrusion ◽

River Estuary ◽

Dry Season ◽

Water Levels ◽

Spatial And Temporal Variation ◽

Indus River ◽

Wet Season ◽

Dry Seasons

<p>Field investigations were conducted to study the seasonal variation of hydrodynamics and sediment transport in Indus River Estuary (IRE), Pakistan. The data of water levels, currents, salinity, and suspended sediment concentration (SSC) were collected hourly covering both wet and dry seasons. Tidal amplitudes were higher near the mouth than those at the middle and upper estuary. The ebb phase lasted longer than that of the flood during the wet season. The asymmetric tidal pattern with higher ebb velocity was observed during the wet season. A slight difference in current velocity was found during the dry season. The flood currents were higher at middle estuary than those in wet season. During the wet season, salinity variation within a tidal cycle slightly increased from the upper estuary to the mouth. Salinity was substantially higher during the dry season than the wet season at all three stations, with the absence of the flood-ebb variation, showing a strong saltwater intrusion. The SSC data revealed that the sediments were mainly brought into the estuary by freshwater discharge during the wet season. Sediment re-suspension process persists during the dry season, due to the tidal currents. A stronger saltwater intrusion occurred in the dry season due to weak river discharge. An estuarine turbidity maximum zone was formed near station-2 due to the combined effects of tides, river discharge and saltwater intrusion. Overall, field observations have shown a significant spatial and temporal variation in flood/ebb and wet/dry seasons for hydrodynamics and sediment transport in IRE.</p>

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The seasonal changes of the gut microbiome of the population living in traditional lifestyles are represented by characteristic species-level and functional-level SNP enrichment patterns

BMC Genomics ◽

10.1186/s12864-021-07372-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Xue Zhu ◽

Jiyue Qin ◽

Chongyang Tan ◽

Kang Ning

Keyword(s):

Gut Microbiome ◽

Seasonal Changes ◽

Dry Season ◽

Urban Setting ◽

Snp Analysis ◽

Wet Season ◽

Human Gut ◽

Human Gut Microbiome ◽

Genome Level ◽

Prevalent Species

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.

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Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Diversity ◽

10.3390/d13070319 ◽

2021 ◽

Vol 13 (7) ◽

pp. 319

Author(s):

Cristian Pérez-Granados ◽

Karl-L. Schuchmann

Keyword(s):

Air Temperature ◽

Daily Rainfall ◽

Climatic Conditions ◽

Dry Season ◽

Climate Impacts ◽

Calling Behavior ◽

Wet Season ◽

Focal Species ◽

Calling Activity ◽

Vocal Activity

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.

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Inorganic Nitrogen Production and Removal along the Sediment Gradient of a Stormwater Infiltration Basin

Water ◽

10.3390/w13030320 ◽

2021 ◽

Vol 13 (3) ◽

pp. 320

Author(s):

Qianyao Si ◽

Mary G. Lusk ◽

Patrick W. Inglett

Keyword(s):

Removal Efficiency ◽

N Mineralization ◽

Inorganic Nitrogen ◽

Dry Season ◽

Pollutant Removal ◽

Net N Mineralization ◽

Wet Season ◽

Inorganic N ◽

N Removal ◽

Stormwater Infiltration

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.

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Seasonal evolution of aerosol stratigraphy in Ürümqi glacier No. 1 percolation zone, eastern Tien Shan, China

Annals of Glaciology ◽

10.3189/172756406781812041 ◽

2006 ◽

Vol 43 ◽

pp. 245-249 ◽

Cited By ~ 10

Author(s):

Feiteng Wang ◽

Zhongqin Li ◽

Xiaoni You ◽

Chuanjin Li ◽

Huilin Li ◽

...

Keyword(s):

Wind Erosion ◽

Sampling Site ◽

Chemical Species ◽

Early Summer ◽

Tien Shan ◽

Wet Season ◽

Surface Layers ◽

Different Depths ◽

Physical And Chemical ◽

Percolation Zone

AbstractThe processes involved in the evolution of vertical profiles of Mg2+, Ca2+ and microparticle concentrations, as well as their seasonal variation in surface snow, were studied by weekly sampling from September 2003 to September 2004 of a snow pit on Ürümqi glacier No. 1, eastern Tien Shan, China. The development of the microparticle and Mg2+ and Ca2+ stratigraphy in the snow pit is closely related to the physical development of the snow–firn pack. The sampling site is located at 4130 ma.s.l. in the percolation zone of the glacier, and in addition to the effects of sublimation and wind erosion, melting plays a crucial role in both the physical and chemical evolution processes. During the winter, soluble aerosol concentrations in the surface layers are altered slightly by sublimation and wind erosion, and the concentrations are further modified as the wet season begins in late April. In contrast, soluble aerosol stratigraphy in the deeper layers remains relatively unchanged through the winter. In early summer, as melting occurs in the upper part of the snow–firn pack, meltwater carries chemical species to different depths in the underlying snow–firn layers, such that at the end of the ablation season, all of the surface cations might be leached out from the upper layers. In addition, the possible source of calcium and magnesium is discussed in this paper.

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