Location Of Sampling Sites Research Articles

Post-caldera evolution of Deception Island (Bransfield Strait, Antarctica) over Holocene timescales

The study of palaeoclimatic changes in fast warming regions can contribute to the understanding of the forcing mechanisms responsible for the global changes that are presently happening. Deception is an active volcanic island in the Bransfield basin that has a complex history strongly influenced by both magmatic and tectonic processes. However, without accurate information on the distribution of melt, depth of sediments and Holocene timescales of its volcanic eruptions, the models for the post-caldera evolution of Deception Island are poorly constrained. Although this region has undergone severe environmental changes due to recent eruptions, hindering the location of potential study areas of paleo-volcanic eruptions, it is still possible to reconstruct post-caldera evolution at a local scale. Employing analyses such as radiocarbon dating, stable carbon and nitrogen isotopic compositions and particle-size distributions in subsoil horizons, we have studied the coastal areas of Whalers Bay and between Wensleydale Beacon and Cross Hill to identify the major periods of alluvial sedimentation on Deception Island. Whalers Bay was influenced by a large amount of moving water generated by ice melting. The coastal location of both sampling sites contributes to preserve the sedimentation history in their soil profiles, despite the severe environmental changes due to recent eruptions. Our findings indicate that from approximately 13 to 5 cal kyr BP, the accumulation of organic matter was stable and the landforms were not altered. After that time, post-caldera eruptions occurred, melting the glacier and, consequently, flooding surficial soil layers with mud. These changes are consistent with old 14C ages for subsoil organic matter and, therefore, with the occurrence of intense cryogenic disturbance processes.

Effects of extensive bottom cultivation of tropical oyster Crassostrea belcheri on benthic invertebrate community structure in Ban Don Bay, Suratthani Province, Southern Thailand

The diversity, distribution, and species richness of benthic invertebrates were examined under extensive bottom cultivation of the tropical oyster Crassostrea belcheri during the summer of 2015 at Ban Don Bay, Suratthani Province, Southern Thailand. Oyster farms that had been operating for 25 years were selected for the study, and four sampling sites were allocated along each transect as (i) at the center of the farm, (ii) inside the farm, (iii) at the farm boundary, and (iv) a reference site. Results indicated that a total of 23 families and 28 species of benthic invertebrate taxa were recorded from the four sampling sites, and the macrobenthic invertebrates inhabiting all study sites consisted mainly of gastropods (11 species), polychaetes (11 species), and bivalves (8 species). No significant differences in total density, diversity index, evenness index, and species richness index of benthic invertebrates were found among each sampling site (P > 0.05). Significant differences in total nitrogen, nitrate, nitrite, total ammonia, sulfide, total phosphorus, organic matter, and grain sizes of sediment were found among each sampling site, but no significant differences in pH and total nitrogen were found. Among the independent variables analyzed, correlation analysis showed relationships between benthic diversity indices and abiotic variables. There were no clear patterns of differences in the detrimental environmental effects between sampling site locations, which indicated a minimal ecological impact of oyster cultivation.

Effects of locations and growth stages on nutritive value and silage fermentation quality of Leymus chinensis in Eurasian steppe of northern China

AbstractThe objective of the study was to determine the correlation among location of sampling sites, characteristics of Leymus chinensis material and fermentation quality, to examine the effect of growth stage on nutrient composition and fermentation quality, and then to find the main factors for influencing fermentation quality and the optimum harvest stage for ensiling. L. chinensis was harvested from 27 sites in Eurasian steppe of northern China, chopped, ensiled in plastic film bags, and stored in dark for 60 days. Lactic acid bacteria (LAB), fermentation characteristics and nutrient composition were analyzed. The results showed that crude protein (CP) of L. chinensis was >80 g kg–1, and average of neutral detergent fiber and buffering capacity (BC) were 661 g kg–1 and 227 mE kg–1 respectively. The LAB number of silage was <108, the pH >4.50, and the average of lactic acid (LA) and acetic acid (AA) were 5.14 and 9.72 g kg–1 respectively; and V‐Score >80. The water‐soluble carbohydrate (WSC) of L. chinensis correlated negatively with latitude (P < 0.001) and positively with elevation (P < 0.01) of sits based on dry matter (DM) and fresh weight (FW), and CP correlated negatively with latitude (P < 0.05) based on FW. The latitude and elevation of sites correlated significantly (P < 0.05) with LA, LA/AA and ammonia nitrogen/total nitrogen (AN/TN) in L. chinensis silage, and the DM and hemicellulose of material had significant correlation with propionic acid (P < 0.05) and AN/TN (P < 0.05) of L. chinensis silage based on DM and FW. L. chinensis had lower CP (P < 0.05) and BC (P < 0.05), and higher cellulose (P < 0.05) with advancing growth stage; the silages harvested at boot stage were well fermented compared with heading and flowering stages. Those results indicated that L. chinensis is a good forage for ruminants, L. chinensis silage is well preserved, there are negative effect of latitude and positive effect of elevation on the WSC in L. chinensis, and the latitude and elevation of sites, and the DM and hemicellulose of material are main factors of affecting the fermentation quality of L. chinensis silage. The optimum harvest stage for ensiling L. chinensis is boot stage.

Correlations Between Life-Detection Techniques and Implications for Sampling Site Selection in Planetary Analog Missions.

We conducted an analog sampling expedition under simulated mission constraints to areas dominated by basaltic tephra of the Eldfell and Fimmvörðuháls lava fields (Iceland). Sites were selected to be “homogeneous” at a coarse remote sensing resolution (10–100 m) in apparent color, morphology, moisture, and grain size, with best-effort realism in numbers of locations and replicates. Three different biomarker assays (counting of nucleic-acid-stained cells via fluorescent microscopy, a luciferin/luciferase assay for adenosine triphosphate, and quantitative polymerase chain reaction (qPCR) to detect DNA associated with bacteria, archaea, and fungi) were characterized at four nested spatial scales (1 m, 10 m, 100 m, and >1 km) by using five common metrics for sample site representativeness (sample mean variance, group F tests, pairwise t tests, and the distribution-free rank sum H and u tests). Correlations between all assays were characterized with Spearman's rank test. The bioluminescence assay showed the most variance across the sites, followed by qPCR for bacterial and archaeal DNA; these results could not be considered representative at the finest resolution tested (1 m). Cell concentration and fungal DNA also had significant local variation, but they were homogeneous over scales of >1 km. These results show that the selection of life detection assays and the number, distribution, and location of sampling sites in a low biomass environment with limited a priori characterization can yield both contrasting and complementary results, and that their interdependence must be given due consideration to maximize science return in future biomarker sampling expeditions. Key Words: Astrobiology—Biodiversity—Microbiology—Iceland—Planetary exploration—Mars mission simulation—Biomarker. Astrobiology 17, 1009–1021.

Factors affecting the bacterial community composition and heterotrophic production of Columbia River estuarine turbidity maxima.

Estuarine turbidity maxima (ETM) function as hotspots of microbial activity and diversity in estuaries, yet, little is known about the temporal and spatial variability in ETM bacterial community composition. To determine which environmental factors affect ETM bacterial populations in the Columbia River estuary, we analyzed ETM bacterial community composition (Sanger sequencing and amplicon pyrosequencing of 16S rRNA gene) and bulk heterotrophic production (3H‐leucine incorporation rates). We collected water 20 times to cover five ETM events and obtained 42 samples characterized by different salinities, turbidities, seasons, coastal regimes (upwelling vs. downwelling), locations, and particle size. Spring and summer populations were distinct. All May samples had similar bacterial community composition despite having different salinities (1–24 PSU), but summer non‐ETM bacteria separated into marine, freshwater, and brackish assemblages. Summer ETM bacterial communities varied depending on coastal upwelling or downwelling conditions and on the sampling site location with respect to tidal intrusion during the previous neap tide. In contrast to ETM, whole (>0.2 μm) and free‐living (0.2–3 μm) assemblages of non‐ETM waters were similar to each other, indicating that particle‐attached (>3 μm) non‐ETM bacteria do not develop a distinct community. Brackish water type (ETM or non‐ETM) is thus a major factor affecting particle‐attached bacterial communities. Heterotrophic production was higher in particle‐attached than free‐living fractions in all brackish waters collected throughout the water column during the rise to decline of turbidity through an ETM event (i.e., ETM‐impacted waters). However, free‐living communities showed higher productivity prior to or after an ETM event (i.e., non‐ETM‐impacted waters). This study has thus found that Columbia River ETM bacterial communities vary based on seasons, salinity, sampling location, and particle size, with the existence of three particle types characterized by different bacterial communities in ETM, ETM‐impacted, and non‐ETM‐impacted brackish waters. Taxonomic analysis suggests that ETM key biological function is to remineralize organic matter.

Influence of seasonality, air mass origin and particulate matter chemical composition on airborne bacterial community structure in the Po Valley, Italy

The integration of chemical and biological data in aerosol studies represents a new challenge in atmospheric science. In this perspective it will be possible to gain a clearer and deeper comprehension of biogeochemical cycles in the atmosphere.In this view, this study aimed to investigate the relationships occurring between bacterial populations and PM chemical composition in one of the most polluted and urbanized areas in Europe: the Po Valley (Italy). Moreover, seasonality, long- and short-range transports were also evaluated to investigate the influence on airborne bacterial communities.PM samples were collected in two cities of the Po Valley (Milan and Venice) characterized by different meteorological conditions and atmospheric pollutant sources. Samples were analysed for water-soluble inorganic ions (WSIIs) and bacterial community structure. Chemical and biological data were jointly processed by using redundancy discriminate analysis (RDA), while the influence of atmospheric circulation was evaluated by using wind ground data and back-trajectories analysis.Results showed strong seasonal shifts of bacterial community structure in both cities, while a different behaviour was observed for air mass circulation at Milan ad Venice sites: long-range transport significantly affected bacterial populations in Milan whereas local ground wind had more influence in the Venice area. Moreover, difference in taxonomic composition can be mostly addressed to the characteristics of sampling sites. This evidence could suggest that, while PM composition is influenced by long-range transport, bacterial populations are affected, besides transport, by other factors (i.e., season and sampling site location). This perspective allow to better understand and explain airborne bacterial community behaviour.

Ethnobotanical study of medicinal plants from El-Jadida City (Morocco)

Abstract : BRIGUICHE. H, ZIDANE. L. Floristic And Ethnobotanical Studies Of Medicinal Plants Of The City Of El -Jadida (MOROCCO). In the framework of the ethnobotanical studies on medicinal plants undertaken by the Laboratory of Biodiversity and Natural Resources of the Faculty of Sciences of Kenitra (Morocco), we are interested in the area of El Jadida which presents a rather important floristic richness thanks to changes in its ecological conditions By using 204 questionnaire, the ethnobotanical surveys were conducted in the field during the years 2012-2013. The location of the different sampling sites was determined by the stratified sampling method. The analysis of the results obtained from the questionnaires and forms using statistical processing allowed us to identify 70 plant species distributed in 69 genera and 37 families. These results also show that most of these species are mainly used in the care of the digestive system and respiratory system. The seed is the most used part in local traditional medicines and the decoction is the most frequent mode with a rate of 31%. The species Origanum compactum is the most used by the population of the city of El Jadida 47 quotes.

Monitoring of caesium-137 in surface seawater and seafood in both the Irish and North Seas: trends and observations

The objective of this paper is to compile selected caesium-137 concentrations in seafood and seawater (the key OSPAR indicators) from the data submitted by the United Kingdom to the OSPAR Commission. The impact upon the surrounding environment of the Irish Sea and North Sea has been determined from trends of caesium-137 concentration data over time, from the start of the OSPAR evaluation period to the present date. Generally, caesium-137 concentrations, in each of the key OSPAR indicators (by sample type and site locations), have declined in both the Irish and North Sea environments over the long time period.

Tracking trends in eutrophication based on pigments in recent coastal sediments

Summary Eutrophication in two different coastal areas – the Gulf of Gdansk (southern Baltic) and the Oslofjord/Drammensfjord (Norway) – both subject to human pressure and with restricted water exchange with adjacent seas, was investigated and compared. Sediment cores (up to 20 cm long) were collected at 12 stations using a core sampler, 6 in each of the two areas, and divided into sub-samples. The physicochemical parameters characterizing the adjacent water column and near-bottom water, i.e. salinity, oxygen concentration and temperature, were measured during sample collection. Chlorophylls-a, -b and -c, their derivatives and selected carotenoids were determined for all the samples, as were additional parameters characterizing the sediments, i.e. Corg, Ntot, δ13C and δ15N, grain size. 210Pb activity was also determined and on that basis sediment mixing and accumulation rates were estimated. The distribution of pigments in sediments was related to environmental conditions, the sampling site location and sediment characteristics. The results are in agreement with other observations that eutrophication in the Gulf of Gdansk has increased, especially since the 1970s, whereas in the Oslofjord it decreased during the same period. The pigments are better preserved in inner Oslofjord sediments than in those from the Gulf of Gdansk. The results demonstrate that the sum of chloropigments-a in sediments calculated per dry weight of sediments is a valuable measure of eutrophication, providing that the monitoring site is selected properly, i.e. sediments are hypoxic/anoxic and non-mixed. Besides, the results confirm previous observations that the percentages of particular chlorophyll-a derivatives in the sum of chloropigments-a are universal markers of environmental conditions in a basin. The ratios of chloropigments-b and chlorophylls-c to the sum of chloropigments-a (ΣChlns-b/ΣChlns-a; Chls-c/ΣChlns-a) may by applied as complementary markers of freshwater and marine organic matter input, respectively.

Temporal and spatial variability of Chironomidae (Diptera) species emergence in a Neotropical estuary

AbstractWe analyzed temporal (day-to-day) and spatial (site-to-site) variability of chironomid (Diptera) communities from Laguna del Tortuguero, Costa Rica, to refine a collection protocol that can be used in designs of bioassessments of Neotropical estuaries. We made chironomid pupal exuviae collections on 7 consecutive sampling dates at 3 fixed sampling sites during both the wet and dry seasons. We identified 98 species and 44 genera from 2601 specimens. The 4 most abundant genera accounted for 71% of exuviae. Species-accumulation curves reached saturation for both dry- and wet-season samples, and ∼70% of the cumulative species richness was detected after 3 sampling dates across 3 fixed sampling sites. Species diversity appeared to be structured by sampling-site location along a salinity gradient but not sampling date within a season. Based on the Sorensen incidence-based (SI) and abundance-based (SA) similarity indices, cumulative dry- and wet-season samples were highly similar (SI: 0.701, SA: 0.986). ...

Contributions of body size, habitat and taxonomy to predictions of temperate Australian fish diets

Using k- nearest neighbour procedures to predict prey type and linear models to predict mean prey size, we developed a 2-step dietary model based on the stomach contents of fish of known species, size and location from Western Port, Victoria (Australia). The model, nicknamed ‘Consume’, was used to assess the relative extent to which fish diet varied with body size, species identity, season, and location. Both prey type (mean overlap between predicted and actual prey types = 77%) and mean prey size (r 2 between predicted and observed mean prey size = 93%) were predicted with reasonable accuracy when species identity and length of consumer fish were known. The most important predictor for prey type was the size of the individual consumer, while the most important predictor for mean prey size was the consumer’s taxonomic identity. Predictors were individually removed from both k -nearest neighbour and linear models to assess their relative contributions to the model. Little loss of accuracy (1%) was evident when family rather than species identity was used for both prey type and mean prey size. Environmental information associated with the time and location of fish sampling (habitat, site and season) contributed only marginally to predictions of prey type. Use of the Consume model will allow for an improved understanding of community-level trophic pathways through the integration of prey type and size predictions for consumer fishes.

Fetoplacental regional variations in the expression of angiopoietin-1, angiopoietin-2, and Tie2 in normal-term and near-term pregnancies

Background: Angiopoietin-1 (Ang1), angiopoietin-2 (Ang2), and the receptor tyrosine kinase with immunoglobulin-like and EGF-like domains 2 (Tie2) are known to be involved in fetoplacental angiogenesis adequacy, which is a primary determinant of fetal growth. Regional variations in Ang1, Ang2, and Tie2 remain unknown, although fetoplacental vascularity and gene expressions differ between the placental center and the periphery.Objective: The aim of this study was to test the hypothesis that there are regional variations in the expression of these angiopoietins in human placentas from uncomplicated term and near term pregnancies.Study design: In this prospective study, central and peripheral samples were collected from fresh placentas from normal-term and near-term pregnancies delivered by Cesarean section (n = 7, 36–41 week gestation) prior to the onset of labor. Regional differences in Ang1, Ang2, and Tie2 protein expressions were measured by Western blot and densitometric analyses with b-actin normalization, and their fetoplacental regional localization assessed by immunohistochemistry. The Ang1 and Ang2 ratios at central and peripheral sites were determined. Statistical analysis was performed using Student’s t-test.Results: Ang1 protein expression was higher in the placental periphery than in the center (2.48 ± 0.42 versus 1.74 ± 0.27, p = 0.01). In contrast, Ang2 protein expression was greater in the placental center than in the periphery (10.10 ± 1.82 versus 7.15 ± 1.12, respectively, p = 0.03). The Ang1–Ang2 ratio reflected these differential expressions. Tie2 protein expression was higher in the placental periphery than in the center (0.21 ± 0.02 versus 0.16 ± 0.02, p = 0.003). The immunoreactivity of Ang1 and Tie2 was stronger in the periphery than in the center, and that of Ang2 was stronger in the center than in the periphery.Conclusions: Ang1, Ang2, and Tie2 are differentially expressed in placental center and periphery. Ang1/Ang2 ratio reflects this regional variation in the angiogenic balance that has implications for fetoplacental villous angiogenesis. The results also demonstrate the importance of considering the location of placental sampling sites for any future investigations of fetoplacental villous angiogenesis.

Environmental impact of mining activity in Bor area as indicated by the distribution of heavy metals and bacterial population dynamics in sediment

The environmental impact of inorganic pollution is pronounced in water adjacent to Bor Copper Smelter Complex (RTB Bor, Serbia), with Cu, Zn, Pb, and As being the main determinants of aquatic pollution pattern. Communities of microorganisms present in the sediments are mainly affected by heavy metal pollution. Some groups of bacteria can be considered pollution bio-indicators, due to their sensibility and ability to bioaccumulate heavy metals, thus contributing to reducing pollution. This study investigates the relationships between trace element accumulation and heterogeneity in sediment bacteria community structure found in water streams adjacent to the Bor Copper Smelter Complex (RTB Bor, Serbia). Our results showed no contamination with copper, zinc, nickel, iron, and chromium, but did show a low to moderate contamination with lead and a moderate to high contamination with arsenic in aquatic sediments within the area of interest. Spatial heterogeneity in sediment-associated bacterial communities did not relate significantly to location of sampling sites, except for iron reducing bacteria. Iron reducing bacteria and nitrifying bacteria were the best distinguishing groups of bacteria. However, only iron reducing bacteria were significantly influenced by sampling locations. The iron reducing bacteria has correlated negatively with the degree of sediment contamination with lead, and therefore, we suggest that this group of bacteria could serve as potential bio-indicators of inorganic water contamination in Bor RTB area.

Organic carbon in water, particulate matter, and upper layer of bottom sediments of the central part of the Kara Sea

Based on data obtained in the course of the 59th cruise of RV Akademik Mstislav Keldysh, the content of organic carbon was determined in water (dissolved organic carbon, DOC), particulate matter (particulate organic carbon, POC), and bottom sediments of the Yenisei estuary and of the central part of the Kara Sea during the summer–autumn season of 2011. The decisive impact of the waters of riverine runoff upon the variability of DOC and POC concentrations in the marine aquatic area is shown. POC enrichment in the autochthonous component is revealed for the frontal zones, as well as the increase of DOC concentrations in the area of the northern extremity of the Novaya Zemlya Islands. The distribution map of organic carbon (Corg) in the upper layer of bottom sediments of the central part of the Kara Sea is plotted on the basis of the analysis of the authors' and published data. A pronounced enrichment of the thin upper layer (0–0.5 cm) of bottom sediments in organic carbon (>20%) is registered at most of the stations and depends neither on lithological composition of sediments nor on the location of sampling sites.

Post-earthquake anomalies in He–CO2 isotope and relative abundance systematics of thermal waters: The case of the 2011 Van earthquake, eastern Anatolia, Turkey

We report the helium and carbon isotope (3He/4He, δ13C) and relative abundance (CO2/3He) characteristics of hydrothermal gases from eastern Anatolia sampled ~1month after the October 23, 2011 Van earthquake (Mw: 7.2, focal depth: 19km). Seven sites were sampled which comprise three localities along the Çaldıran Fault Zone, at a distance of 58–66km to the epicenter (Group I), two localities north of the Çaldıran Fault, about 90–113km from the epicenter (Group II), and two localities in the vicinity of the historically-active Nemrut Caldera at a distance of 110–126km from the epicenter (Group III). All sites were previously sampled for their He–CO2 systematics in 2009 (Mutlu et al., 2012) facilitating direct comparison with the post-earthquake dataset.The post-earthquake values cover a wide range of 3He/4He, δ13C and CO2/3He ratios, from 0.84 to 6.37RA (where RA=air 3He/4He), −5.30 to +0.49‰ (vs. VPDB), and 4.9×1010 to 6.85×1013, respectively. Group I samples show a consistent post-earthquake increase in 3He/4He whereas both Group II localities decreased in 3He/4He. No change was recorded for the two Group III localities. He isotope variations are consistent with simple changes in the proportions of mantle and crustal volatiles, with all Group I sites showing an increase in the mantle He contribution. We hypothesize that the enhanced mantle He signal is derived from asthenospheric melts intruded into the crust, with seismic perturbations responsible for bubble formation and growth leading to overpressure and gas loss. The strike–slip Çaldıran Fault Zone provides the permeable pathway for the liberated volatiles to reach hydrothermal systems at shallow levels of the crust and the surface. Release of crustal He dominates the He mass balance of Group II samples as locations are further from the earthquake epicenter. Group III samples are even further away from the earthquake and show no perturbations in He isotopes. Whereas binary mixing dominates the He isotope systematics, CO2 shows additional effects involving the hydrothermal system. Consequently, changes in the balance between mantle and crustal CO2 are masked and more difficult to discern. The results emphasize the sensitivity of He isotopes to seismic perturbations in the crust and illustrate how location of sampling sites – on permeable segments of faults – and distance from seismic events influence resulting changes involving gas chemistry.

Plant sampling uncertainty: a critical review based on moss studies

Estimates of the distribution, migration, and accumulation of trace elements using mosses as bioindicators have successfully been used in biomonitoring studies since at least the 1970s. Chemical analysis of moss samples is also an important tool for assessing concentrations of elements in analyzed material at a given time. To achieve satisfactory accuracy in environmental studies, the best sampling approach must be used. Methods for the estimation of uncertainty derived from analytical procedures are well recognized, but the errors generated as a result of sampling are very often overlooked. Sampling uncertainty can be managed by a judicious selection of the sampling method, the amount of samples collected, and by following appropriate type of sampling protocols. The sampling protocol generally contains information about location of sampling sites, time of sampling (e.g., season), the species collected, type of sample (single, sub-sample), and monitored parameters (e.g., climate, analyzed substances). Information about seasonal variability; topographic, climatic, edaphic, and hydrologic conditions (type and amount of precipitation, rosewind); age; and part of plant that was collected is often ignored. There is no precise information on how these factors affect the sampling step and overall uncertainty over what procedures must be followed to reduce errors derived from plant sampling. This information is necessary when long-range and comparative studies are conducted. In this paper, we review how individual factors, such as (i) type of sampling strategy, (ii) representative sampling, (iii) seasonal variability, and (iv) which part of the plant is collected, may influence the concentration of trace elements in moss tissues and the level of uncertainty associated with sampling. In addition, we also discuss plant sample preparation techniques and how this may cause an uncontrolled element loss.

Design of sampling locations for river water quality monitoring considering seasonal variation of point and diffuse pollution loads.

The design of a water quality monitoring network (WQMN) is a complicated decision-making process because each sampling involves high installation, operational, and maintenance costs. Therefore, data with the highest information content should be collected. The effect of seasonal variation in point and diffuse pollution loadings on river water quality may have a significant impact on the optimal selection of sampling locations, but this possible effect has never been addressed in the evaluation and design of monitoring networks. The present study proposes a systematic approach for siting an optimal number and location of river water quality sampling stations based on seasonal or monsoonal variations in both point and diffuse pollution loadings. The proposed approach conceptualizes water quality monitoring as a two-stage process; the first stage of which is to consider all potential water quality sampling sites, selected based on the existing guidelines or frameworks, and the locations of both point and diffuse pollution sources. The monitoring at all sampling sites thus identified should be continued for an adequate period of time to account for the effect of the monsoon season. In the second stage, the monitoring network is then designed separately for monsoon and non-monsoon periods by optimizing the number and locations of sampling sites, using a modified Sanders approach. The impacts of human interventions on the design of the sampling net are quantified geospatially by estimating diffuse pollution loads and verified with land use map. To demonstrate the proposed methodology, the Kali River basin in the western Uttar Pradesh state of India was selected as a study area. The final design suggests consequential pre- and post-monsoonal changes in the location and priority of water quality monitoring stations based on the seasonal variation of point and diffuse pollution loadings.

Temporal changes in soil salinity at four saline wetlands in NE Spain

The knowledge of soil salinity and the temporal changes of its distribution in the soil profiles can give warnings for the protection of saline habitats. This study described and compared the salinity profiles of the soils from four hypersaline wetlands at inland, ill-drained depressions in NE Spain, which were sampled throughout the year in 1979–1980 and 1999–2000, and differed in land use. The halophytic communities dictated the location of sampling sites. After the saturated pastes of 404 soil samples were prepared, the electrical conductivity of the extracts (ECe) and the concentrations of major ions were measured, and additional supplementary analyses were performed. A subset of the samples was titrated for calcium carbonate equivalent and gypsum content. ECe and ion concentrations calculated for synthetic soil layers facilitated the comparisons of the vertical distribution of soil salinity among dates, depths, and sites. The shape of the mean ECe profiles over all sampling dates indicated moderate differences between the two wetlands closest to each other, Plan de Callén (PC) and Paúl de Almuniente (AL), which had similar (<~10dSm−1) ECe. In contrast, the ECe profile at Paúl de Anzano (AN) ranged from 40dSm−1 to 50dSm−1 in the upper meter of the soil, which decreased steadily to 20dSm−1 at a 2-m depth. At Saladar de Agustín (AG), ECe was much higher and the profile had the opposite shape, ECe~55dSm−1 at the surface and >80dSm−1 at an 80-cm depth. The shape of ECe profiles at AL, PC, and AG was rather stable over time, contrasting with the measured desalination of the soil at AL after its conversion into a rice paddy. The changes in the sodium adsorption ratio (SAR) in the soil profiles at AN, PC, and AL are indicators of the potential extremes in the hydric behavior of the soils. At AG, the mineralogical clays are a minor component of these gypseous soils; therefore, the SAR, only, was used as a measure of the relative concentrations of Na+ versus Ca2+ plus Mg2+. The median SAR of all AG soil samples did not differ significantly among sampling sites or dates. The shorter sampling depth intervals used in 1979–80 were responsible for the greater spread in the distribution and the increase in extreme SAR values compared to the data collected in 1999–2000.

Disturbance and stress gradients result in distinct taxonomic, functional and phylogenetic diversity patterns in a subtropical riparian tree community

AbstractQuestionsWhat are the key environmental variables that influence the structure of riparian forests? Do disturbance (flooding) and stress (soil fertility) gradients result in functionally and phylogenetically different riparian forests? Do patterns of functional and phylogenetic diversity follow patterns of taxonomic diversity?LocationSubtropical riparian tree community, Turvo State Park, Rio Grande do Sul state, southern Brazil.MethodsWe collected data on nine functional traits and assembled a phylogeny for all tree species found in a sample with 100 plots. We then modelled species richness and evenness, and functional and phylogenetic richness, evenness and divergence as functions of flooding frequency and soil fertility. Next, we used a three‐table ordination method to look for associations between environmental conditions, the spatial locations of sampling sites and the distributions of species, trait values and lineages. We conducted these analyses for the entire area and separately for three habitats with different flooding frequencies. Finally, we tested for phylogenetic signal in functional traits.ResultsSpecies richness and evenness were highest under intermediate flooding frequency. In contrast, functional richness was negatively correlated with soil fertility, while phylogenetic richness increased with both flooding frequency and soil fertility (with phylogenetic evenness following a similar trend). Functional evenness was lowest under intermediate flooding frequency, and functional and phylogenetic divergence correlated in a complex quadratic way with both flooding and soil fertility. Functional traits were generally conserved in the phylogeny, although pioneer establishment strategy and resprouting capacity were convergent and strongly associated with frequent flooding. In contrast, the distribution of lineages was not associated with either environmental variables or site location.ConclusionsThere was a mismatch between taxonomic, functional and phylogenetic diversity patterns along disturbance and stress gradients. This mismatch likely occurs because functional traits involved in species sorting were either convergent or conserved in the phylogeny and because disturbance and stress gradients seem to differently affect each of the assessed diversity components. Even though disturbance seems to be the key driver of the structure of riparian tree communities, stress gradients (soil fertility) are the key predictors of important diversity components, especially functional richness. Thus, disturbance and stress gradients result in functionally and phylogenetically different riparian tree communities, leading to differences that cannot be predicted from differences in species richness and composition alone.

Passive measurement of NO2 and application of GIS to generate spatially-distributed air monitoring network in urban environment

Nitrogen dioxide (NO2) plays an important role in atmospheric chemistry through formation of secondary particulate nitrate that contributes a major portion to the mass of particulate matter (PM) that has several impacts on the environment in the scales of local, regional and global. NO2 is regulated in most of the countries, because it acts as a precursor for nitrate formation and it shows significant negative effects on human health. The present study was conducted for measurement of NO2 concentration at 204 and 101 sampling locations in two Indian large cities (population more than 4 million), Delhi and Kanpur, respectively by using passive samplers. From the experimental results, an average concentration of 68.6±20.1μg/m3 was observed in Delhi and it was 36.9±12.1μg/m3 in Kanpur. The observed data from all sampling sites were utilized on the platform of Geographic Information System (GIS) to generate spatially distributed pollution maps (using Kriging interpolation method) and maps of probability of exceedences of air quality standards. Based on the survey results on emission activities, meteorology and pollution maps, this study proposed locations of air quality sampling sites for a long-term monitoring network in Delhi and Kanpur.