Mechanisms controlling major ion chemistry and its suitability for irrigation of Narmada River, India

Surface water chemistry of the upper Narmada River was investigated at 13 different locations for 4 consecutive years (2017 to 2020) during pre- and post-monsoon seasons. The main objective of the study was to identify the processes governing the water chemistry of Narmada River and evaluate its suitability for irrigation. The physical parameters estimated were; pH (7.9 ± 0.4 for pre- and 8 ± 0.4 for post-monsoon seasons), EC (322.8±93.3 μS/cm for pre- and 312.1±80.2 μS/cm for post-monsoon) and TDS (203.4±41.5 mg/L for pre-and 213.4±48 mg/L for post-monsoon). The obtained concentration of cations and anions were in the order of Ca++ > Na+ > Mg++> K+ and HCO3−> Cl−>SO4−> NO3−> PO4− respectively. Thus, the water of Narmada was found to be alkaline in nature. Piper diagram inferred that the water was dominated by Ca-Mg-HCO3− type of hydrochemical faces. Gibb's plot clarified that rock-water interaction regulates the ion chemistry of the Narmada. Various indices like sodium percentage (Na%), sodium absorption ration (SAR), Kelly index (Ki), permeability index (PI), magnesium hazard (MH) was calculated which showed that the surface water was suitable for irrigation. Lastly, one-way ANOVA (p < 0.05) confirmed no significant differences in water quality except for temperature, EC and SO4−, for pre- and post-monsoon season.

Optimization of Landsat Chl-a Retrieval Algorithms in Freshwater Lakes through Classification of Optical Water Types

The application of remote sensing data to empirical models of inland surface water chlorophyll-a concentrations (chl-a) has been in development since the launch of the Landsat 4 satellite series in 1982. However, establishing an empirical model using a chl-a retrieval algorithm is difficult due to the spatial heterogeneity of inland lake water properties. Classification of optical water types (OWTs; i.e., differentially observed water spectra due to differences in water properties) has grown in favour in recent years over traditional non-turbid vs. turbid classifications. This study examined whether top-of-atmosphere reflectance observations in visible to near-infrared bands from Landsat 4, 5, 7, and 8 sensors can be used to identify unique OWTs using a guided unsupervised classification approach in which OWTs are defined through both remotely sensed reflectance and surface water chemistry data taken from samples in North American and Swedish lakes. Linear regressions of algorithms (Landsat reflectance bands, band ratios, products, or combinations) to lake surface water chl-a were built for each OWT. The performances of chl-a retrieval algorithms within each OWT were compared to those of global chl-a algorithms to test the effectiveness of OWT classification. Seven unique OWTs were identified and then fit into four categories with varying degrees of brightness as follows: turbid lakes with a low chl-a:turbidity ratio; turbid lakes with a mixture of high chl-a and turbidity measurements; oligotrophic or mesotrophic lakes with a mixture of low chl-a and turbidity measurements; and eutrophic lakes with a high chl-a:turbidity ratio. With one exception (r2 = 0.26, p = 0.08), the best performing algorithm in each OWT showed improvement (r2 = 0.69–0.91, p < 0.05), compared with the best performing algorithm for all lakes combined (r2 = 0.52, p < 0.05). Landsat reflectance can be used to extract OWTs in inland lakes to provide improved prediction of chl-a over large extents and long time series, giving researchers an opportunity to study the trophic states of unmonitored lakes.

Drivers, pressures, and state responses to inform long-term oil sands wetland monitoring program objectives

Boreal peatlands provide numerous ecosystem services ranging from carbon sequestration to the provisioning of habitat for species integral to Indigenous communities. In the Oil Sands Region of Alberta, Canada, human development related to oil and gas extraction occurs in a wetland-dominated landscape. Wetland monitoring programs can determine the extent to which development impacts wetlands, but existing monitoring programs focus on characterizing biodiversity across the region and on compliance and regulatory monitoring that assumes impacts from oil sands development do not extend past lease boundaries. This is unlikely to be true since some impacts, such as particulate deposition, can extend over large areas contingent on local weather and topography. To inform the development of a new regional wetland monitoring program to assess the cumulative effects of oil sands development on wetlands, we synthesized information on the scope of wetland research across the Oil Sands Region, including the anthropogenic stressors that impact wetlands and the wetland characteristics sensitive to different disturbances. We developed a conceptual model linking human development with wetland ecology in the region to make explicit the relationships among oil sands development stressors and different components of wetland ecosystems. By highlighting testable relationships, this conceptual model can be used as a collection of hypotheses to identify knowledge gaps and to guide future research priorities. relationships among We found that the majority of studies are short-term (77% were ≤ 5 years) and are conducted over a limited spatial extent (82% were sub-regional). Studies of reclaimed wetlands were relatively common (18% of all tests); disproportionate to the occurrence of this wetland type. Results from these studies likely cannot be extrapolated to other wetlands in the region. Nevertheless, the impacts of tailings contaminants, wetland reclamation activities, and surface water chemistry are well-represented in the literature. Research on other types of land disturbance is lacking. A coordinated, regional monitoring program is needed to gain a complete understanding of the direct and indirect impacts of human development in the region and to address remaining knowledge gaps.

Effects of biotransport and hydro-meteorological conditions on transport of trace elements in the Scott River (Bellsund, Spitsbergen)

The shaping of surface water chemistry in the Svalbard Archipelago is strongly dependent on the geology of the catchment and the process of long-range transport of atmospheric pollutants (LRATP). It was found that the dissolved trace elements in the Scott River, which catchment is characterized by a decreasing degree of glaciation, were of the natural origin (i.a. weathering and dissolution of local geological substratum). The exception was Zn originated from LRATP. The paper describe the influence changes in hydro-meteorological conditions and the presence of a seabird colony on the variability in the transport of trace elements within the Scott River catchment. The work assesses long-time fluctuations in the concentration of twenty five trace elements (i.a. Al, Cr, Cu, Pb, Sr, and Zn) from eighty-four surface water samples and their relation to changes in water discharge (Q), precipitation (P), pH, and dissolved organic carbon (DOC) at two river sites (with one being under the influence of the biotransport factor). Based on the results of matrix correlation and cluster analysis it was found that the additional load of DOC from the nesting site of Larus Argentatus in the mouth section of the river drastically changed the hydro-geochemical cycle of Co, Ni, Zn, Ga, Sr, Rb, Ba and U (0.30 < r < 0.51). Furthermore, the results of cluster analysis confirmed that the bird colony’s nesting site was strongly responsible for the presence of U, Rb, Zn, Ni and marine-derived nutrients (e.g. Se and Li). The discharge of glacier meltwater and the alkaline character of water have a negative effect on the dissolution of Li and Mn (−0.31 < r < −0.51), but positively affect the level of Rb and U (r = 0.31 and 0.35, respectively) due to it being washing out a seabird nesting colony in the mouth section of the Scott River. It was observed that the event of rises in air temperature and rain, which results in increased water discharge, caused an intense transport of the trace elements load. Moreover, results of the precipitation sensitivity coefficient factor (CF) proved that precipitation effect the occurrence of Li, Sr and U in the Scott River.

Application of Multivariate Statistical Analysis and Water Quality Index for Quality Characterization of Parbati River, Northwestern Himalaya, India

The present study is an attempt to accomplish the understanding of the factors impacting surface water quality of Parbati river in Kullu district of Himachal Pradesh. The main objective is to assess the overall water quality, to explore its hydrogeochemical characteristics including major ion contents and other chemical parameters using Water Quality Index (WQI), statistical techniques (principal component analysis) and conventional graphical representation such as Piper trillinear diagram, Durov. Eighteen surface water sampling sites were selected to analyze physico-chemical parameters for June 2019 and September 2019. Analytical outcomes of thirty six surface water samples for both seasons are well within the permissible limits as per BIS, 2012 & WHO 2011 for drinking and domestic purposes. Water quality characterization for the assigned use shows that maximum surface water samples falls under excellent to good water quality index and are suitable for drinking without conventional treatment. The Piper trillinear diagram classified 100% of surface water samples for both seasons’ falls in the fields of Ca2+ - Mg2+ -HCO3− water type indicating temporary hardness. Abundance of ions in the water samples is in the order: anions HCO3− > Cl−> SO42−>NO3− and cations Mg2+> Ca2+> Na+> K+. PCA identifies that the surface water chemistry is influenced by natural factors as well as minor anthropogenic activities in both the seasons.

The Surface Water Chemistry (SWatCh) database: A standardized global database of water chemistry to facilitate large-sample hydrological research

Openly accessible global scale surface water chemistry datasets are urgently needed to detect widespread trends and problems, to help identify their possible solutions, and identify critical spatial data gaps where more monitoring is required. Existing datasets are limited in availability, sample size/sampling frequency, and geographic scope. These limitations inhibit the answering of emerging transboundary water chemistry questions, for example, the detection and understanding of delayed recovery from freshwater acidification. Here, we begin to address these limitations by compiling the global surface water chemistry (SWatCh) database, available on Zenodo (DOI: https://doi.org/10.5281/zenodo.4559696) We collect, clean, standardize, and aggregate open access data provided by six national and international agencies to compile a database consisting of three relational datasets: sites, methods, and samples, and one GIS shapefile of site locations. We remove poor quality data (for example, values flagged as suspect), standardize variable naming conventions and units, and perform other data cleaning steps required for statistical analysis. The database contains water chemistry data across seven continents, 17 variables, 38,598 sites, and over 9 million samples collected between 1960 and 2019. We identify critical spatial data gaps in the equatorial and arid climate regions, highlighting the need for more data collection and sharing initiatives in these areas, especially considering freshwater ecosystems in these environs are predicted to be among the most heavily impacted by climate change. We identify the main challenges associated with compiling global databases – limited data availability, dissimilar sample collection and analysis methodology, and reporting ambiguity – and provide recommendations to address them. By addressing these challenges and consolidating data from various sources into one standardized, openly available, high quality, and trans-boundary database, SWatCh allows users to conduct powerful and robust statistical analyses of global surface water chemistry.

Biodiversity and DNA degradation patterns recorded in a 2200-year-long sequence of sedimentary ancient DNA from the afrotropical Bwindi Impenetrable Forest, Uganda

&lt;p&gt;Most of the Earth&amp;#8217;s biodiversity is concentrated in the tropics. While the ultimate causes of this geographic pattern remain to be established, ongoing anthropogenic impacts in the tropical belt lead to rapid losses of species diversity. Ancient DNA approaches may help in deciphering temporal patterns in the diversification of tropical biota and could potentially provide historical baseline data on the diversity and distribution of species in anthropogenically modified landscapes. However, studies of sedimentary ancient DNA (sedaDNA) are thus far extremely rare in tropical settings and consequently its value as a conservation tool for tropical ecosystems remains to be tested systematically. To address this issue we present meta-genomic records of shot-gun sequenced sedimentary ancient DNA (sedaDNA) from several sediment cores from the equatorial Bwindi-Impenetrable Forest in Uganda. Because Bwindi is one the most diverse rainforests in Africa and its biota is well documented (including endangered species such Mountain Gorilla and Chimpanzee) it is well suited for a baseline study. We describe the taxonomic composition of sedaDNA from Bwindi for the past 2200 years at an average resolution of 50 years &amp;#8211; one of the first comprehensive sedaDNA records of plant and animal taxa from a tropical rainforest. We specifically address the following questions: 1) How precisely can the taxonomic level of shotgun-sequenced tropical sediments be resolved at present? 2) What is the effect of temperature, acidity, nutrient availability, elemental and lithological sediment composition, and burial age on the degradation of DNA? Taxonomic assignments are based on three metagenomic classifiers and four reference databases and their reliability tested against local pollen and modern animal occurrence data. We find that 92.3% of our metagenomic data is taxonomically not identifiable due to the substantial underrepresentation of tropical taxa in genomic reference databases. Yet at ordinal level we reconstruct typical afrotropical assemblages, which do not decline in diversity over time. Our comprehensive set of ecological and sedimentological parameters including sediment age, surface water chemistry, pH, soil temperature, sediment density, sediment water and organic matter content, XRF elemental chemistry, nutrient concentrations, and magnetic susceptibility reveals that DNA degradation cannot be explained by any sedimentary parameter alone, is at Bwindi independent of sediment type, and most likely primarily driven by burial age, suggesting that DNA taphonomic models need to be site-specific in tropical environments. The viability of sedaDNA as a conservation-biology tool requires comprehensive genomic surveys of tropical biota to drastically improve the taxonomic representativeness of DNA reference databases.&lt;/p&gt;

Metals alter membership but not diversity of a headwater stream microbiome

Metal contamination from mining or natural weathering is a common feature of surface waters in the American west. Advances in microbial analyses have created the potential for routine sampling of aquatic microbiomes as a tool to assess the quality of stream habitat. We sought to determine if microbiome diversity and membership were affected by metal contamination and identify candidate microbial taxa to be used to indicate metal stress in stream ecosystems. We evaluated microbiome membership from sediments at multiple sites within the principal drainage of an EPA superfund site near the headwaters of the Upper Arkansas River, Leadville, CO. From each sample, we extracted DNA and sequenced the 16S rRNA gene amplicon on the Illumina MiSeq platform. We used the remaining sediments to simultaneously evaluate environmental metal concentrations. We also conducted an artificial stream mesocosm experiment using sediments collected from two of the observational study sites. The mesocosm experiment had a 2x2 factorial design: 1) location (upstream or downstream of contaminating tributary), and 2) treatment (metal exposure or control). We found no difference in diversity between upstream and downstream sites in the field. Similarly, diversity changed very little following experimental metal exposure. However, microbiome membership differed between upstream and downstream locations and experimental metal exposure changed microbiome membership in a manner that depended on origin of the sediments used in each mesocosm. Importance Our results suggest that microbiomes can be reliable indicators of ecosystem metal stress even when surface water chemistry and other metrics used to assess ecosystem health do not indicate ecosystem stress. Results presented in this study in combination with previously published work on this same ecosystem are consistent with the idea that a microbial response to metals at the base of the food web may be affecting primary consumers. If effects of metals are mediated through shifts in the microbiome, then microbial metrics, as presented here, may aid in the assessment of stream ecosystem health which currently does not include assessments of the microbiome.