Presence Of Freshwater Research Articles

Determination of microplastics in sediment, water, and fish across the Orange-Senqu River basin

Microplastics are increasingly recognised as posing a significant environmental threat across systems. Their pervasive presence in freshwater poses a serious concern, given the heavy reliance of both humans and biodiversity on healthy, functioning freshwater ecosystems. Acknowledgment of the potential risks led the transboundary Orange-Senqu River Commission (ORASECOM) to include sampling for microlitter (primarily microplastics) in riverine sediment, surface water, and fishes, across Southern Africa as part of the third Joint Basin Survey (JBS3) in 2021. The aim was to establish a first, basin-wide estimate of microlitter contamination across compartments, setting a baseline for further monitoring. The survey showed that the abundance of microlitter in riverine sediment (0 – 4000 particles.kg-1 dry weight (dw)) and riverine water (1.00 ± 0.71 – 69.75 ± 68.55 SD items.L-1) varied considerably between sample sites, with no correlation between the two. The abundance of microlitter in fishes was low (average of 0.7 ± 0.4 items.individual-1). Course resolution analyses suggested that microlitter concentrations in riverine sediment and riverine water at each site did not correlate with land use directly upstream, though variation in microlitter abundance did isolate some hotspots of contamination. Discharge data collected from nine gauging stations near sampling sites confirmed that low flows prevailed in the system during the study, with high flows occurring approximately 5 months prior during the summer months. There is some variation in river flow across the catchment which is a likely driver of microlitter transport. This was evident in the polymer composition for sediment and water samples. Based on the average discharge at each gauging station and microlitter concentrations measured in riverine water, the estimated microlitter load ranged from ∼889 particles.s-1 to ∼17.9 million particles.s-1, with a substantial amount ending likely up in the mudbelt adjacent to the Orange River mouth. This assessment provides a first insight into the characterisation and distribution of microlitter in multiple compartments across the Orange-Senqu River basin. Overall, the findings highlight the need for continued monitoring across compartments at catchment scales to improve our understanding of microplastic pathways into and within riverine systems.

Hydrochemical and geoelectrical investigation to determine the origin and spatial distribution of the salinization of the unconfined Plio-Quaternary aquifer of Tabeditt, Southern Tunisia

The expansion of irrigated agriculture and the overexploitation of groundwater in the Tabeditt region lead to a serious deterioration of the chemical quality of water. The compilation of hydrogeological and geophysical studies is essential in order to assess the quality of the Plio-Quaternary waters and to determine the origin of the salinization of these waters. In this study, hydrochemical analyses were carried out on groundwater samples in the Tabeditt region. Hydrochemical data have shown that the salinity in this area could exceed 6 g/L. The interpretation of major ion analyses demonstrates that mineralization is controlled by natural processes. The mineralization process consists of the dissolu-tion of evaporite minerals, namely gypsum, anhydrite, and halite. The geoelectrical study is carried out to obtain information about the distribution and quality of water in the Plio-Quaternary. Interpreta-tion of the resistivity models show the presence of two main zones: the first, near Tabeditt Wadi, is characterized by low values, indicating the influence of salt water in the groundwater and the second, located on the right bank of Wadi Jmal, is characterized by variable resistivity values, generally high, indicating the lateral changes in lithological facies, and the presence of fresh water. In such an arid region suffering from scarcity and degradation (or depletion) of water resources, it is important to implement a master plan that keeps under control the number of wells both known and unknown ones taping these aquifers.

Environmental Heterogeneity and Salinity Gradient Impacted the Alpha and Beta Diversities of Diatom Assemblages in a Coastal Delta Wetland

The coastal deltas are ecologically diverse and complex ecosystems that can contain different habitat types. The effect of environmental heterogeneity on diatom beta diversity is a poorly understood research topic. Freshwater (floodplain forest, river) and brackish (three lagoons) water bodies in the study area construct distinct environmental heterogeneity at a small spatial scale. The connection of the lagoons with an inland sea caused a high salinity gradient. All water bodies in the wetland were determined as hypereutrophic. CCA, Cluster, ANOSIM, and SIMPER analysis clearly explained the distribution of diatom assemblages according to salinity gradient and environmental heterogeneity. The environmental heterogeneity resulted in the presence of freshwater, brackish, and marine diatom species in the studied wetland. Diatom assemblages generally consist of freshwater species with euryhaline character adapted to wide salinity gradients. We determined the rapid replacement and richness difference in diatom assemblages due to environmental heterogeneity and salinity gradient causes high overall alpha, beta, and gamma diversity. Unlike many other studies, the high beta diversity mainly consists of the richness difference rather than species replacement. The high overall beta diversity showed low similarity between the habitats, while high overall alpha diversity exposed high species diversity at the local scale in the study area.

Benthic sediment as stores and sources of bacteria and viruses in streams: A comparison of baseflow vs. stormflow longitudinal transport and residence times

The presence of bacteria and viruses in freshwater represents a global health risk. The substantial spatial and temporal variability of microbes leads to difficulties in quantifying the risks associated with their presence in freshwater. Fine particles, including bacteria and viruses are transported and accumulated into shallow streambed (i.e., benthic) sediment, delaying the downstream transmission during baseflow conditions but contributing to their resuspension and transport downstream during stormflow events. Direct measurements of pathogen accumulation in benthic sediments are rare. Until now, the dynamic role of benthic sediment as both a store and source of microbes, has not been quantified. In this study, we analyze microbial abundance in benthic sediment along a 1 km reach of an intermittent Mediterranean stream receiving inputs from the effluent of a wastewater treatment plant, a known point source of microbes in streams. We sampled benthic sediment during a summer drought when the wastewater effluent constituted 100 % of the stream flow, and thus, large accumulation and persistence of pathogens along the streambed was expected. We measured the abundance of total bacteria, Escherichia coli (as a fecal indicator), and presence of enteric rotavirus (RoV) and norovirus (NoV). The abundance of E. coli, based on qPCR detection, was high (4.99∙102 gc /cm2) along the first 100 m downstream of the wastewater effluent input and in general decreased with distance from the source, with presence of RoV and NoV along the study reach. A particle tracking model was applied, that uses stream water velocity as an input, and accounts for microbial exchange into, immobilization, degradation, and resuspension out of benthic sediment during baseflow and stormflow. Rates of exchange into benthic sediment were 3 orders of magnitude higher during stormflow, but residence times were proportionately lower, resulting in increased longitudinal connectivity from up to downstream during stormflow. Model simulations demonstrated mechanistically how the rates of exchange into and out of the benthic sediment resulted in benthic sediment to act as a store during baseflow and a source during stormflow.

Predictors of successful return to parkrun for first-time adult participants in Scotland.

Physical activity is essential for promoting good health and reducing burdens on healthcare systems. parkrun organise free weekly events where participants complete a 5km route. Studies have identified characteristics of participants associated with lower levels of participation. The aim of the study was to identify predictors of the likelihood of returning to parkrun for first-time adult participants. The return rate of adult first-time participants was determined for all 5km parkrun events in Scotland over a 1-year period from February 2019. The dataset consisted of 20,191 adult participants made up of 11,459 females and 8,732 males across 58 venues. A General Linear Mixed Model was used to identify factors associated with return rate. Return rates were negatively correlated with event size and positively correlated with the proportion of first-time adult participants at the event. Age was positively correlated with return rate and males were more likely to return. New participants that finished in a relatively slow time were disproportionately less likely to return. Return rates were positively correlated with the amount of freshwater and woodland on the route. These findings provide potential opportunities to manage events to enhance their efficacy. Specific events could be promoted as first-timer days to encourage new participants to attend together. New events could be prioritised in proximity to events that currently experience high attendances to reduce attendances locally. As the presence of freshwater and woodland are associated with higher return these habitats could play a role in generating the benefits of green exercise. If so the creation of more routes running through or alongside these habitats could be beneficial. The findings are likely to be widely applicable to other mass participation events and those interesting in understanding the mechanism by which green exercise provides its benefits.

Экспериментальные исследования гидратообразования природного газа в пористой среде в присутствии растворов хлорида и гидрокарбоната натрия

The paper presents the results of investigation of the natural gas hydrates formation and decomposition in quartz sand in the presence of fresh water, sodium bicarbonate (0,25 and 2 mass%) and chloride (5 mass%) solutions. The selected solutions are models of stratum water of subpermafrost aquifers of the Vilyui syneclise. The study of the porous medium and salinity influence on the hydrate formation was carried out by differential thermal analysis at initial gas pressures from 4 to 7 MPa. Equilibrium conditions and kinetic parameters of the hydrate formation were determined. The kinetic parameters of the hydrate formation in porous media, depending on salinityand at each value of the initial pressure decrease in the following sequence: 0,25 mass% NaHCO3 H2O > 2 mass% NaHCO3 > 5 mass% NaCl. The stability of hydrates obtained in porous media with different salinity has been studied. It has been established that the hydrates stability in porous media decreases with an increase of the solution concentration.

Pharmaceutical pollution in marine waters and benthic flora of the southern Australian coastline

Environmental context Most human pharmaceutical waste is discharged to the environment. While the presence of pharmaceuticals in freshwater systems is well documented globally, little is known of the impact on marine ecosystems. We measured pharmaceuticals in a marine environment in south-eastern Australia and found pharmaceutical concentrations around 24 000 times higher in benthic flora than in the marine surface waters. We discuss the potential use of seaweeds as biological indicators of pharmaceutical pollution. Rationale Pharmaceuticals are emerging pollutants of concern with a range of adverse consequences for organisms and ecosystems. Their presence in freshwater and estuarine systems has been well documented, but less is known about their prevalence in open ocean, or their uptake by benthic flora. This preliminary survey of the southern Australian coastline sought to measure the concentrations of key pharmaceuticals in both surface waters and benthic flora. Methodology This study used LC-MS/MS to measure the concentration carbamazepine, tramadol and venlafaxine in (1) samples from wastewater treatment plants, (2) ocean surface waters and (3) several species of benthic flora. Surface waters and benthic flora were sampled at two sites near waste water treatment plant (WWTP) discharges, and one site away from any discharge. Results All three pharmaceuticals were detected in surface water samples with their risk assessed (via risk quotient) as medium risk (carbamazepine) or low risk (venlafaxine, tramadol). All three pharmaceuticals were also detected in benthic flora, particularly in brown macroalgae; Tramadol was measured at a maximum of 34.7 ng g−1 in Hormosira banksii, and Venlafaxine was recorded at a maximum of 17.3 ng g−1 in Caulocystis cephalornithos. Discussion The calculated bioconcentration factors suggest the pharmaceutical concentrations in benthic flora were up to ~24 000 times higher than in surrounding surface water. There was also evidence that proximity to WWTP outfalls influenced the levels of pharmaceuticals in benthic flora. The results suggest that the benthic flora may be suitable bioindicators of pharmaceutical contamination and that the potential impacts of pharmaceutical pollutants in marine ecosystems demand further investigation.

Fluorescence-based selective nitrite ion sensing by amino-capped carbon dots

Nitrite ions pose a severe problem to human health justifying the need for fast and reliable detection of their presence in freshwater. Here we report a method to detect nitrite by photoluminescence of amino-rich carbon dots (C-dots). The dots are synthesized from p-phenylenediamine through a solvothermal treatment in ethanol. When nitrites ions are present in acidic water samples, the C-dots amino groups undergo diazotization and quench the C-dots emission at 535 nm, enabling the detection. The synthesis does not require a purification step as the unreacted species do not interfere with the nitrites sensing. The C-dots photoluminescence shows a linear quenching in the 6–75 µM concentration range which is below the concentration limits allowed for nitrites in drinking water. The effect of interferent metal ions in the water sample is also discussed, and an optimized protocol to achieve a precise readout is proposed.

Thermodynamic and kinetic characterization of methane hydrate ‘nucleation, growth and dissociation processes, according to the labile Cluster theory

Methane hydrates were formed and then dissociated in presence of fresh water and a pure quartz porous medium, by using a small-scale experimental apparatus, appositely designed for those experiments. The most significant phases describing the process, or nucleation, massive growth and dissociation, were characterized both thermodynamically and kinetically. Methane hydrate equilibrium was defined in presence of such porous medium and the hydrate formation rate was calculated for kinetic considerations. To do this, the Labile Clusters Theory was considered and, according to it, hydrate formation was considered a first-order chemical kinetic equation for the time dependence. Finally, pressure variation over time was discussed. The comparison between trend assumed by those parameters revealed consistent and visible similarities, which allowed to a very deepened characterization about all three phases making up the whole process.

Submarine groundwater discharge detection on the coast of Buenos Aires using 222Rn and geoelectrical methods

Submarine groundwater discharge (SGD) is a complex hydrological process which occurs in the continent–ocean interface and plays an important role in coastal dynamics. The detection of groundwater discharge from the sandy freshwater aquifer towards the Atlantic Ocean was proposed on the western coast of Buenos Aires Province (Argentina). There are different methods used to detect SGD. In this study, 222Rn as a tracer, electrical resistivity tomography (ERT) and flow maps were used as the methodology. 222Rn activity was measured in the wells, at the beach (tidal pools and surf zone) and along a transect 200 m from the coastline where geo-electrical method was also used. Groundwater depth was measured in the wells and groundwater contour maps were made .222Rn activity in the wells varies from 16 and 173 dpm/L, at the beach the values are between 28 and 48 dpm/L and along the coastline they oscillate between 1.3 and 20.5 dpm/L. The ERT shows a high resistivity layer close to a depth of 3-4 m from the sea floor, which would indicate the presence of freshwater. Groundwater contour maps show discharge toward the continental plain to the west and toward the sea to the east. There is no precedent related to the application of these methodologies in the study area, therefore this study is of interest to increase our knowledge of the coastal hydrodynamics.

Benthic Diatom Composition in Coastal Zone of Black Sea, Sasyk Reservoir (Ukraine)

The Sasyk Reservoir is one of the largest seaside reservoirs in Ukraine, artificially maintained as a freshwater area including various floodplain areas. The Reservoir originated from an estuary to now being an almost freshwater reservoir. The diatoms (Bacillariophyta) in benthos were investigated for analyzing the coastal zone diversity of the Black Sea inside the borders of Ukraine. The indicated diatom composition was formed by 97 species (100 infraspecies taxa). Some rare marine and freshwater taxa were noted, as well as three species reported in Ukrainian territory for the first time (Navicula vandamii Schoeman et R.E.M. Archibald, Sellaphora difficillima (Hustedt) C.E. Wetzel, L. Ector et D.G. Mann, and Mastogloia laterostrata Hustedt). The bioindicative characteristics of the diatom composition testified to the freshwater condition of the reservoir. Changes to the salinity level of the Sasyk Reservoir were exposed due to the composition of benthic diatoms. The presence of mesohalobous species (7 taxa) acknowledges conditions that are typical for estuaries and mouths of rivers and reveals the salinity changes in the Sasyk Reservoir. Likewise, the prevailing number of oligohalobous diatoms (61 taxa) reveal presence of freshwater in the reservoir. The implementation of the Polish phytobenthos lake assessment method for the nearby Ukrainian Reservoir was conducted for the first time. The multimetric Diatom Index for lake values varied from 0.39 to 0.76, and revealed alterations in the status over the Sasyk sites, ranging from good, moderate, to poor. Thus, it may be concluded that the current ecological status relating to the composition of benthic diatoms of the reservoir located in the coastal zone of the Black Sea is evaluated as having a moderate status class with some exceptions.

Development and evaluation of a DGT sampler using functionalised cross-linked polyethyleimine for the monitoring of arsenic and selenium in mine impacted wetlands

Arsenic and selenium are both carcinogenic and their presence in fresh water has attracted the development of robust and accurate monitoring techniques. A new diffusive gradients in thin-films (DGT) sampler was developed and evaluated for the in situ measurements of arsenic and selenium. The binding layer was made from a mixture of sulphonated and phosphonated cross-linked polyethylenimine (SCPEI and PCPEI, respectively). The optimum ratio of a SCPEI and PCPEI resin mixture was determined. The DGT sampler was calibrated under laboratory conditions to determine the influence of sample turbulence, concentration and pH. The optimised DGT passive sampler was field deployed in a mine impacted dam for 12 days. Binding layer optimisation shows that the polymers had to be mixed in a specific ratio of 80% sulphonated and 20% phosphonated per 0.8 g of the resin mixture, in the loose polymer form. Embedding the resin mixture in agarose gel reduced the uptake of both arsenic and selenium dramatically. At sample pH 3.0 and 5.0, the DGT sampler did not show significant differences in uptake of the two elements during the 15 day deployment. The passive sampler had limited adsorption capacity and was found better suited for dilute solutions, with concentrations below 0.5 mg L−1 of the target metals. This effect was more pronounced when exposed to dam water which had competing cations. Cations may have reduced the capacity by binding to the PEI backbone via the large number of amine groups. Nonetheless, these cations did not show linear uptake.

Bromate removal from water intended for human consumption by heterogeneous photocatalysis: Effect of major dissolved water constituents

This study focuses on the influence of major dissolved constituents naturally found in waters intended for human consumption on bromate (BrO3−) reduction by heterogeneous photocatalysis. The individual and combined effect of chloride (Cl−), bicarbonate/carbonic acid (HCO3−/H2CO3), nitrate (NO3−), sulphate (SO42−) and humic acids (HAs) on BrO3− reduction was evaluated in synthetic waters (SWs). Additionally, freshwaters (FWs) from a drinking water treatment plant (DWTP) were tested and directly compared to SWs. Cl− was beneficial for contents in the range 0.47–1.4 mM, with negligible influence for lower and higher contents. NO3− had a null effect regardless of its content (0.024–0.81 mM). HCO3−/H2CO3 (0.061/0.45 mM), SO42− (0.12–2.6 mM) and HAs (0.11–1.0 mM C) had a negative effect in the tested contents. The BrO3− reduction rate was 2.8 times lower in SW with a mixture of water constituents compared to SW without constituents addition. This decline on BrO3− reduction rate corresponded to the sum of the individual species contribution and so there was no evidence of synergetic effects. By contrast, the use of FWs provided BrO3− reduction rates only slightly lower than that found for SW without constituents addition (∼1.2-fold), which can be attributed to: (i) the distinct characteristics of the organic matter of FWs (HAs, fulvic acids and humins with distinct molecular weights and functional groups) compared to that of SW (pure HAs), and/or (ii) the presence in FWs of other inorganics in addition to those here addressed. The heterogeneous TiO2 photocatalysis proved to be a promising process for BrO3− reduction in DWTPs.

Concentrations levels and effects of 17alpha-Ethinylestradiol in freshwater and marine waters and bivalves: A review

Pharmaceutical drugs are contaminants of emerging concern and are amongst the most frequent in the aquatic environment. Even though a vast literature indicate that pharmaceuticals exert negative impacts towards aquatic organisms, mainly in vertebrates, there is still limited information regarding the effects of these drugs in freshwater and marine bivalves. Marine bivalves have a high ecological and socio-economic value and are considered good bioindicator species in ecotoxicology and risk assessment programs. Furthermore, another lacking point on these studies is the absence of bioconcentration data, with no clear relationship between the concentration of drugs on tissue and the biological effects. 17alpha-ethinylestradiol (EE2) is a synthetic hormone with high estrogenic potency that was added to the Watch List adopted by the European Commission stating the priority substances to be monitored. Thus, this review summarizes the current knowledge on the concentration levels and effects of EE2 on freshwater and marine bivalves. The inclusion in the Watch List, the presence in freshwater and marine systems, and the impact exerted on aquatic biota, even at trace concentrations, justify the review devoted to this pharmaceutical drug. Globally the available studies found that EE2 induces individual and sub-individual (e.g. tissue, cellular, biochemical and molecular levels of biological organization) impacts in bivalves. Essentially, this estrogenic compound, even in trace concentrations, was found to have accumulated in wild and laboratory exposed bivalves. The most common effects reported were changes on the reproductive function and energy metabolism. The studies used in this review support keeping the EE2 on the Watch List and highlight the need to increase the number of monitorization studies since clear negative effects were exerted on bivalves by this drug.

Widespread Dominance of Kinetoplastids and Unexpected Presence of Diplonemids in Deep Freshwater Lakes.

Kinetoplastid flagellates are generally abundant in the deep sea and recently they were even found to be dominant in the hypolimnion of a deep freshwater lake. Therefore, to understand the distribution of kinetoplastids in deep freshwater lakes, we have collected vertical samples from five lakes in Japan. The abundance of kinetoplastids was enumerated by Catalyzed Reporter Deposition-Fluorescence in situ Hybridization, and the diversity was determined by 18S amplicon sequencing using universal eukaryote and kinetoplastid-specific primers. Kinetoplastids were abundant in the deep waters of all the lakes, contributing up to 53.6% of total nanoeukaryotes. Despite this significant contribution, kinetoplastids remain undetected by amplicon sequencing using universal primers that are widely used in eukaryotic diversity studies. However, they were detected with specific primers, and the communities were characterized by both ubiquitous and lake-specific unique OTUs. Oligotyping of a ubiquitous and dominant OTU revealed the presence of lake-specific sequence types (oligotypes). Remarkably, we also detected diplonemids (a sister group of kinetoplastids and considered to be specific in the marine habitat) using kinetoplastid-specific primers, showing their presence in freshwaters. Underestimation of kinetoplastids and diplonemids using universal primers indicates that euglenozoan flagellates are overlooked in diversity studies worldwide. The present study highlighted the importance of kinetoplastids in the hypolimnion of deep lakes, thereby indicating their role in material cycling in deep waters.

A multi-parameter study of groundwater–seawater interactions along Partido de La Costa, Buenos Aires Province, Argentina

Submarine groundwater discharge (SGD) is a complex hydrological process which occurs at the continent–ocean interface and plays an important role in coastal dynamics. The main objective of this study was to detect groundwater discharge from the sandy freshwater aquifer towards the Atlantic Ocean along the western coast of Buenos Aires Province (Argentina) using multiple methods. 222Rn as a tracer, electrical resistivity tomography (ERT), and hydrogeological information were applied to detect and quantify SGD. 222Rn activity was measured in wells, at the beach (tidal pools and surf zone) and along a transect ~ 200 m from the coastline coincident with geoelectrical measurements. Groundwater depth was measured in wells, and from these data, groundwater contour maps were made. 222Rn activity in wells varies from 16 and 173 dpm/L; at the beach, the values are between 28 and 48 dpm/L; and along the coastline, they oscillate between 1.3 and 20.5 dpm/L. The ERT shows a high resistivity layer close to 3–4 m depth from the sea floor indicating the presence of freshwater. Groundwater contour maps show discharge toward the continental plain to the west and toward the sea to the east. There is no precedent related to the application of these methodologies in the study area which results of interest for the knowledge of the coastal hydrodynamics.

Neighbourhood blue space, health and wellbeing: The mediating role of different types of physical activity

BackgroundEvidence suggests that living near blue spaces such as the coast, lakes and rivers may be good for health and wellbeing. Although greater levels of physical activity (PA) may be a potential mechanism, we know little about the types of PA that might account for this. ObjectivesTo explore the mediating role of: a) ‘watersports’ (e.g. sailing/canoeing); b) ‘on-land outdoor PA’ in natural/mixed settings (e.g. walking/running/cycling); and, c) ‘indoor/other PA’ (e.g. gym/squash) in the relationships between residential blue space availability and health outcomes. MethodsUsing data from the Health Survey for England (n = 21,097), we constructed a path model to explore whether weekly volumes of each PA type mediate any of the relationships between residential blue space availability (coastal proximity and presence of freshwater) and self-reported general and mental health, controlling for green space density and a range of socio-economic factors at the individual- and area-level. ResultsSupporting predictions, living nearer the coast was associated with better self-reported general and mental health and this was partially mediated by on-land outdoor PA (primarily walking). Watersports were more common among those living within 5kms of the coast, but did not mediate associations between coastal proximity and health. Presence of freshwater in the neighbourhood was associated with better mental health, but this effect was not mediated by PA. ConclusionsAlthough nearby blue spaces offer potentially easier access to watersports, relatively few individuals in England engage in them and thus they do not account for positive population health associations. Rather, the benefits to health from coastal living seem, at least in part, due to participation in land-based outdoor activities (especially walking). Further research is needed to explore the mechanisms behind the relationship between freshwater presence and mental health.

Pseudomonas Diversity Within Urban Freshwaters.

Freshwater lakes are home to bacterial communities with 1000s of interdependent species. Numerous high-throughput 16S rRNA gene sequence surveys have provided insight into the microbial taxa found within these waters. Prior surveys of Lake Michigan waters have identified bacterial species common to freshwater lakes as well as species likely introduced from the urban environment. We cultured bacterial isolates from samples taken from the Chicago nearshore waters of Lake Michigan in an effort to look more closely at the genetic diversity of species found there within. The most abundant genus detected was Pseudomonas, whose presence in freshwaters is often attributed to storm water or runoff. Whole genome sequencing was conducted for 15 Lake Michigan Pseudomonas strains, representative of eight species and three isolates that could not be resolved with named species. These genomes were examined specifically for genes encoding functionality which may be advantageous in their urban environment. Antibiotic resistance, amidst other known virulence factors and defense mechanisms, were identified in the genome annotations and verified in the lab. We also tested the Lake Michigan Pseudomonas strains for siderophore production and resistance to the heavy metals mercury and copper. As the study presented here shows, a variety of pseudomonads have inhabited the urban coastal waters of Lake Michigan.

Characterization and spatio-temporal dynamics of Cylindrospermopsis raciborski in an Amazonian Lagoon, Ecuador.

The cyanobacteria Cylindrospermopsis raciborskii, is a fresh water ubiquitous species from tropical to temperate weather. It is potentially capable of producing toxins. Thus it is necessary to monitor its presence in fresh waters associated to recreational use activities and human consumption. There are official reports and one thesis reporting the presence of C. raciborskii in Ecuador. Nevertheless, this country does not appear in the latest distribution maps of this species in the scientific literature. In this article, we report the presence of C. raciborskii in Ecuador, together with the characterization of the environmental conditions of one of the habitats where this species is present: the Limoncocha lagoon, province of Sucumbíos.

Wastewater treatment plants as a source of microplastics in river catchments

It is now well established that the oceans contain significant accumulations of plastic debris but only very recently have studies began to look at sources of microplastics (MPs) in river catchments. This work measured MPs up- and downstream of six wastewater treatment plants (WWTPs) in different catchments with varying characteristics and found that all led to an increase in MPs in rivers. Nevertheless, the data collected indicated that there were other important sources of MPs in the catchments studied and that these may include atmospheric deposition, agricultural land to which sewage sludge has been applied, and diffuse release of secondary MPs following the breakdown of larger plastic items. MPs were comprised mainly of fibres, fragments, and flakes with pellets and beads only dominating at one site. Variation in MP pollution occurred over time and this difference was greater at some sites than others. A key research need is the further study of MP sources in river catchments to facilitate management efforts to reduce their presence in freshwater and marine environments.