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Abstract Background Seeds of plants are a confirmation of their next generation and come associated with a unique microbia community. Vertical transmission of this microbiota signifies the importance of these organisms for a healthy seedling and thus a healthier next generation for both symbionts. Seed endophytic bacterial community composition is guided by plant genotype and many environmental factors. In north-east India, within a narrow geographical region, several indigenous rice genotypes are cultivated across broad agroecosystems having standing water in fields ranging from 0-2 m during their peak growth stage. Here we tried to trap the effect of rice genotypes and agroecosystems where they are cultivated on the rice seed microbiota. We used culturable and metagenomics approaches to explore the seed endophytic bacterial diversity of seven rice genotypes (8 replicate hills) grown across three agroecosystems. Results From seven growth media, 16 different species of culturable EB were isolated. A predictive metabolic pathway analysis of the EB showed the presence of many plant growth promoting traits such as siroheme synthesis, nitrate reduction, phosphate acquisition, etc. Vitamin B12 biosynthesis restricted to bacteria and archaea; pathways were also detected in the EB of two landraces. Analysis of 522,134 filtered metagenomic sequencing reads obtained from seed samples (n=56) gave 4061 OTUs. Alpha diversity indices showed significant differences in observed OTU richness (P≤0.05) across genotypes. Significant differences were also found between the individual hills of a rice genotype. PCoA analysis exhibited three separate clusters and revealed the clusters separated based on genotype, while agroecosystem showed a minimal effect on the variation of seed microbiota (adonis, R 2=0.07, P=0.024). Interestingly, animal gut resident bacteria such as Bifidobacterium, Faecalibacterium, Lactobacillus, etc. were found in abundance as members of the seed microbiota. Conclusion Overall, our study demonstrates, indigenous rice genotypes of north-east India have a unique blend of endophytic bacteria in their mature seeds. While there are notable variations among plants of the same genotype, we found similarities among genotypes cultivated in completely different environmental conditions. The beta diversity variations across the seven rice genotypes were significantly shaped by their genotype rather than their agroecosystems.

Since the early exploration of the northern North Sea, Triassic sediments have been assigned to terrestrial depositional environments. Evaluation of core data from approximately one hundred wells in the Norwegian and UK sectors of the northern North Sea (58°-62° N), has challenged this interpretation. The sediments of the Smith Bank and Teist formations filled the deepest, syn-rift parts of the basin which in Early Triassic time were the areas closest to the Norwegian mainland, after which the centres of major subsidence shifted farther west. The mudstones of the Smith Bank and Alke formations formed as subaqueous, distal, fine-grained sediments in front of the proximal sand systems of the Lunde and Skagerrak formations. The latter accumulated as two major clastic wedges of deltaic sands derived from major valley systems emerging from the Sognefjord and Hardangerfjord/Boknfjord areas. Standing water was present during progradation of the depositional cones from the east. The depositional pattern was: alluvial to deltaic plain, delta front, subaqueous. Smaller volumes of sediment were shed off the western margin of the basin. The validity of the direct and indirect indicators of standing bodies of water, such as the rare marine and brackish-water fossils, laminae of micritic carbonate, clasts of finely laminated micritic limestone, subaqueous mass flows, wave ripples, intervals of mudstone with high GR readings correlated over semi-regional and regional areas, pyrite, possible submerged lacustrine sand flats and sabkha deposits, as well as the marine incursions into the central part of the basin during deposition of the Lunde and Skagerrak formations, are discussed. [ABSTRACT FROM AUTHOR]

The success of invasive species depends on the overcoming of abiotic and biotic filters. Abiotic variables likely have greater relative importance over invasion at broad spatial scales, while biotic interactions are more important at fine spatial scales. In this study, we tested the hypotheses that (i) the abundance of the invasive Hydrilla verticillata is more correlated with abiotic factors than with competing native species at broad spatial grain; and that (ii) H. verticillata abundance is more correlated with competing native species than with abiotic factors at fine spatial grain. Here, we considered spatial scale as the grain size (i.e., the extent of sampling unit) assuming broad spatial scales as a large area encompassing the entire patches of macrophytes, and fine spatial scales as a small area inside one macrophyte patch. We collected the abundance of hydrilla and the competing native species along with environmental variables in a large subtropical reservoir. To evaluate how the relative importance of the abiotic factors and the competing native species vary between spatial grains we used Bayesian Generalized Linear Models. At broad grain, the abundance of the competing native species, maximum fetch (positive correlation), turbidity and conductivity (negative correlation) were the most important factors to explain the hydrilla abundance. At fine grain, alkalinity, total organic matter of the sediment and the abundance of a competitive native species (all negative correlations) were the most important variables. Our results indicate a greater importance of abiotic factors at broader grains while competitive interactions seem to be important only in the finer spatial grains. Environmental heterogeneity may explain the positive correlation between native and invasive abundances at broad grain, while the negative correlation at fine grain suggests the effect of competition. In synthesis, we show that the abiotic factors that explain the invasion success of a submerged invasive macrophyte are the same in two spatial grains, but the importance of biotic interactions changed with grain. Thus, our data suggest that models that attempt to explain the success of invasive plants, should consider spatial scales.

The success of invasive species depends on the overcoming of abiotic and biotic filters. Abiotic variables likely have greater relative importance over invasion at broad spatial scales, while biotic interactions are more important at fine spatial scales. In this study, we tested the hypotheses that (i) the abundance of the invasive Hydrilla verticillata is more correlated with abiotic factors than with competing native species at broad spatial grain; and that (ii) H. verticillata abundance is more correlated with competing native species than with abiotic factors at fine spatial grain. Here, we considered spatial scale as the grain size (i.e. , the extent of sampling unit) assuming broad spatial scales as a large area encompassing the entire patches of macrophytes, and fine spatial scales as a small area inside one macrophyte patch. We collected the abundance of hydrilla and the competing native species along with environmental variables in a large subtropical reservoir. To evaluate how the relative importance of the abiotic factors and the competing native species vary between spatial grains we used Bayesian Generalized Linear Models. At broad grain, the abundance of the competing native species, maximum fetch (positive correlation), turbidity and conductivity (negative correlation) were the most important factors to explain the hydrilla abundance. At fine grain, alkalinity, total organic matter of the sediment and the abundance of a competitive native species (all negative correlations) were the most important variables. Our results indicate a greater importance of abiotic factors at broader grains while competitive interactions seem to be important only in the finer spatial grains. Environmental heterogeneity may explain the positive correlation between native and invasive abundances at broad grain, while the negative correlation at fine grain suggests the effect of competition. In synthesis, we show that the abiotic factors that explain the invasion success of a submerged invasive macrophyte are the same in two spatial grains, but the importance of biotic interactions changed with grain. Thus, our data suggest that models that attempt to explain the success of invasive plants, should consider spatial scales. [ABSTRACT FROM AUTHOR]

This paper describes two new species and one newly recorded species of the genus Neumania, i.e. N. heterocrus Ding & Jin sp. nov., N. absentiuos Ding & Jin, sp. nov., and N. vietnamicaTuzovsky, 2013, from Jiangxi and Hunan provinces, China. Neumania heterocrus can be distinguished by the sexual dimorphism in leg IV. Neumania absentiuos can be distinguished by P-1 without seta and genital plates close to Cx-IV. Neumania vietnamica can be distinguished by the different swimming setae in leg IV. A key to the members of Neumania form China is provided. The examined specimens are kept in Institute of Entomology, Guizhou University, P. R. China (GUGC). [ABSTRACT FROM AUTHOR]

The condition and feeding behaviour of burbot, a widespread potamodromous species in riverine and lacustrine environments, were compared in order to evaluate the importance of both in three artificial systems. Subadult burbot were sampled in three temperate reservoirs in spring, and one of them also in summer and autumn. Standardised abundance and sizes of burbot were comparable between the reservoirs, but the conditions were significantly different. The Clark’s condition coefficient and index of fullness were independent of burbot size and individuals. Feeding behaviour in terms of abundance and composition of consumed food was environment-dependent. The most common prey category was aquatic insect larvae, dominating in the riverine environment. Permanent water invertebrates, microcrustaceans, beetles and crayfish were less common food and eaten more often in the lacustrine environment. Prey-fish were usually the most common species of suitable size. The food analyses demonstrated opportunistic feeding behaviour with selection of prey associated with benthic habitat and suitable size. Burbot is therefore flexible not only in environments utilisation, but also feeding strategy. [ABSTRACT FROM AUTHOR]

The density and dominance of benthic and epiphytic fauna of selected meioinvertebrate groups were studied in various types of standing water in eastern Poland: two lakes (mesotrophic and polytrophic) and two small water bodies (an oligotrophic pond and a peat-hag). The plants from which the fauna were collected included: Ceratophyllum demersum L., Elodea canadensis Michx., Hydrocharis morsus-ranae L., Myriophyllum spicatum L., Nuphar lutea (L.) Sibth. (i) Sm., Potamogeton natans L., and Stratiotes aloides L. In the taken material, the density and dominance structure of benthic and epiphytic fauna of the taxa Turbellaria, Gastrotricha, Rotifera, and Nematoda were estimated. Total density of the studied phyla in bottom sediments and on elodeids fluctuated from 1315.0 to 3156.0 103 indiv. m-2, and from 2078.0 to 3954.0 103 indiv. m-2, respectively. Mean density of meioinvertebrates per 100 g dry weight of plants in the studied waterbodies amounted to from 125.8 to 289.0 103 indiv. 100 g-1 d.w. The density of meioinvertebrate fauna of elodeids was higher than in bottom sediments in all studied reservoirs and the differences were statistically significant. Epiphytic meioinvertebrate fauna in Lake Bikcze of high trophic level shows low similarity to the mesotrophic one, and to the oligotrophic pond, but shows high similarity to the peat-hag. The development of the meioinvertebrate community on elodeids is mainly affected by the trophic status of the reservoir and not by the character of vegetation. [ABSTRACT FROM AUTHOR]

Pythiosis is a deadly disease of horses, dogs, and other mammals, including humans, in tropical and subtropical regions. In the United States, the disease has been reported in the Southeast as well as in the temperate North and the dry Southwest. The causal agent of pythiosis is Pythium insidiosum, one of few mammalian pathogens in the fungus-like Oomycetes. P. insidiosum has not been studied in the environment in the United States. Given anecdotal reports of pythiosis in Gainesville, Florida dogs, we hypothesized that warm standing water in lakes and ponds in North Central Florida is suitable habitat for P. insidiosum. We sampled 19 lakes or ponds to examine the environmental distribution of P. insidiosum and to determine which of the three previously described genetic clusters of P. insidiosum are present. We found P. insidiosum in 11 of the sampled lakes and ponds. Sequencing of the ITS region separated isolates into three genetic clusters, including a distinct group previously represented by a single isolate from South Carolina. AFLP genotyping of isolates showed genetic variation in Cluster I, which is the group associated with the majority of characterized clinical isolates from the Americas. Our results indicate that animal exposure to P. insidiosum in North Central Florida is common. This study provides the first evidence that P. insidiosummay be more widely distributed in freshwater lakes and ponds in the Southeastern United States than previously appreciated. [ABSTRACT FROM AUTHOR]

Water quality impairment of Great Lakes beaches is caused by fecal pollution from point and nonpoint sources. Erosion due to wind or wave action, invasive vegetation and chronically wet, flooded or standing water are conditions that can magnify water quality problems at beaches. We investigated the hydrological and geophysical characteristics of the Bradford Beach on Lake Michigan (Milwaukee, Wl) and the linkage between standing water and persistent contamination by fecal indicator bacteria (FIB). Our study showed that there is a positive correlation between high concentrations of Escherichia coli (E. coli) in sand and high moisture content caused by standing water. The main factor associated with the formation of standing water was rainfall. There were also notable differences in standing water and/or wet sand conditions in the northern and southern parts of the beach. These differences could be accounted for by differences in ground water elevations and beach erosion and accretion patterns. Other important physical features of the beach were the presence of rain gardens and mean grain diameter (d50 ). Rain gardens above the beach face that capture runoff contributed to transient increases in the water table, facilitating standing water formation. Standing water, stormwater runoff infiltrating through the sand and into groundwater as well as wave run up that delivered contaminated surface water to the back beach area were of health concern following heavy rainfall events. The outcomes of this study will likely be useful to beach managers investigating mechanisms/sources of fecal indicator bacteria loading and potential mitigative approaches. [ABSTRACT FROM AUTHOR]

Abstract: AMSR-E has been extensively evaluated under a wide range of ground and climate conditions using in situ and aircraft data, where the latter were primarily used for assessing the TB calibration accuracy. However, none of the previous work evaluates AMSR-E performance under the conditions of flood irrigation or other forms of standing water. Also, it should be mentioned that global soil moisture retrievals from AMSR-E typically utilize X-band data. Here, C-band based AMSR-E soil moisture estimates are evaluated using 1km resolution retrievals derived from L-band aircraft data collected during the National Airborne Field Experiment (NAFE''06) field campaign in November 2006. NAFE''06 was conducted in the Murrumbidgee catchment area in southeastern Australia, which offers diverse ground conditions, including extensive areas with dryland, irrigation, and rice fields. The data allowed us to examine the impact of irrigation and standing water on the accuracy of satellite-derived soil moisture estimates from AMSR-E using passive microwave remote sensing. It was expected that in fields with standing water, the satellite estimates would have a lower accuracy as compared to soil moisture values over the rest of the domain. Results showed sensitivity of the AMSR-E to changes in soil moisture caused by both precipitation and irrigation, as well as good spatial (average R =0.92 and RMSD =0.049m3/m3) and temporal (R =0.94 and RMSD =0.04m3/m3) agreement between the satellite and aircraft soil moisture retrievals; however, under the NAFE''06 ground conditions, the satellite retrievals consistently overestimated the soil moisture conditions compared to the aircraft. [Copyright &y& Elsevier]

A groundwater mound (or pressure mound) is defined as a volume of fluid dominated by viscous flow contained within a sediment volume where the dominant fluid flow is by Knudsen Diffusion. High permeability self-sealing groundwater mounds can be created as part of a sustainable urban drainage scheme (SUDS) using infiltration devices. This study considers how they form, and models their expansion and growth as a function of infiltration device recharge. The mounds grow through lateral macropore propagation within a Dupuit envelope. Excess pressure relief is through propagating vertical surge shafts. These surge shafts can, when they intersect the ground surface result, in high volume overland flow. The study considers that the creation of self-sealing groundwater mounds in matrix supported (clayey) sediments (intrinsic permeability = 10-8 to 10-30 m3 m-2 s-1 Pa-1) is a low cost, sustainable method which can be used to dispose of large volumes of storm runoff (<20→2,000 m3/24 hr storm/infiltration device) and raise groundwater levels. However, the inappropriate location of pressure mounds can result in repeated seepage and ephemeral spring formation associated with substantial volumes of uncontrolled overland flow. The flow rate and flood volume associated with each overland flow event may be substantially larger than the associated recharge to the pressure mound. In some instances, the volume discharged as overland flow in a few hours may exceed the total storm water recharge to the groundwater mound over the previous three weeks. Macropore modeling is used within the context of a pressure mound poro-elastic fluid expulsion model in order to analyze this phenomena and determine (i) how this phenomena can be used to extract large volumes of stored filtered storm water (at high flow rates) from within a self-sealing high permeability pressure mound and (ii) how self-sealing pressure mounds (created using storm water infiltration) can be used to provide a sustainable low cost source of treated water for agricultural, drinking, and other water abstraction purposes. [ABSTRACT FROM AUTHOR]

Drought is recognized as a primary constraint for rainfed rice production. In this study, the spatial distribution of heading date of rainfed rice and its relation to field water conditions were investigated for 2 years in mini-watersheds called Nong in Northeast Thailand, in order to clarify the toposequential variation in the degree of water stress of rice. Although the difference in the relative field elevation in the mini-watersheds was only a few meters, the water availability in terms of standing water and soil moisture markedly decreased with ascending elevation. Rice cultivars, KDML 105 and RD 6, the two dominant genotypes in Northeast Thailand, reached the heading stage at nearly the same day in the absence of water stress, independent of transplanting or seeding date under customary management. As the water availability decreased with ascending field elevation, the heading date of rice was markedly delayed. The delay seemed to be related to the cumulative water stress before heading of rice. The rice harvest index and yield at farmers’ fields decreased linearly with the delay of heading. The observed toposequential distribution of heading date indicated that quite severe water stress was imposed in the uppermost fields of the mini-watersheds, while practically no water stress occurred in the lower fields, at least in the lower half of the mini-watersheds. These results suggest that the delay of heading is a good index for rice water stress in rice in Northeast Thailand and can be applicable to field classification with respect to drought risk. [Copyright &y& Elsevier]

The article presents a study which discusses the discovery of the fourth species of Anax known as Anax indicus Lieftinck at the Khasala Dam in the district of Rawalpindi, Pakistan on July 14, 2006. It states that this species was identified through comparing its descriptions with Lieftinck and the comparison of the photograph of the A. indicus with the material of the similar A. guttatus. According to the authors, this species usually procreates in standing waters, therefore it affirms the existence of this species at the Khasal Dam. It is believed that this species is the key to all Anax species in the country. Physical descriptions of the species are also provided.