Effects of Recent Volcanic Eruptions on Aquatic Habitat in the Drift River, Alaska, USA: Implications at Other Cook Inlet Region Volcanoes

/ Numerous drainages supporting productive salmon habitat are surrounded by active volcanoes on the west side of Cook Inlet in south-central Alaska. Eruptions have caused massive quantities of flowing water and sediment to enter the river channels emanating from glaciers and snowfields on these volcanoes. Extensive damage to riparian and aquatic habitat has commonly resulted, and benthic macroinvertebrate and salmonid communities can be affected. Because of the economic importance of Alaska's fisheries, detrimental effects on salmonid habitat can have significant economic implications. The Drift River drains glaciers on the northern and eastern flanks of Redoubt Volcano. During and following eruptions in 1989-1990, severe physical disturbances to the habitat features of the river adversely affected the fishery. Frequent eruptions at other Cook Inlet region volcanoes exemplify the potential effects of volcanic activity on Alaska's important commercial, sport, and subsistence fisheries. Few studies have documented the recovery of aquatic habitat following volcanic eruptions. The eruptions of Redoubt Volcano in 1989-1990 offered an opportunity to examine the recovery of the macroinvertebrate community. Macroinvertebrate community composition and structure in the Drift River were similar in both undisturbed and recently disturbed sites. Additionally, macroinvertebrate samples from sites in nearby undisturbed streams were highly similar to those from some Drift River sites. This similarity and the agreement between the Drift River macroinvertebrate community composition and that predicted by a qualitative model of typical macroinvertebrate communities in glacier-fed rivers indicate that the Drift River macroinvertebrate community is recovering five years after the disturbances associated with the most recent eruptions of Redoubt Volcano. KEY WORDS: Aquatic habitat; Volcanoes; Lahars; Lahar-runout flows; Macroinvertebrates; Community structure; Community composition; Taxonomic similarity     

Assessment of deep aquifer groundwater quality in a geographically unique climatic region of Southern Western Ghats,India using water quality indices

Water quality index (WQI) models are generally used in hydrochemical studies to simplify complex data into single values to reflect the overall quality. In this study, deep groundwater quality in the Chittur and Palakkad Taluks of the Bharathapuzha river basin of Kerala, India, was assessed by employing the WQI method developed by the Canadian Council of Ministers of the Environment (CCME). The assessment of overall water quality is indispensable due to the specific characteristics of the study area, such as geography, climate, over-drafting, and prevalent agricultural practices. Forty representative samples were collected from the study area for monsoon (MON) and pre-monsoon (PRM) seasons. The results showed a general increase of contents from MON to PRM. The major cations were spread in the order Ca²⁺>Na+>Mg²⁺>K⁺ and the anions HCO₃⁻>Cl⁻>CO₃²⁻ based on their relative abundance. Among various parameters analysed, alkalinity and bicarbonate levels during MON were comparatively high, which is indicative of carbonate weathering, and 90% of the samples failed to meet the World Health Organization (WHO, 2017)/Bureau of Indian Standards (BIS, 2012) drinking water guidelines. The CCME WQI analysis revealed that nearly 50% of the samples during each season represented good and excellent categories. The samples in the poor category comprised 10% in MON and 15% in PRM. The overall WQI exhibited 15% of poor category samples as well. The spatial depiction of CCME WQI classes helped to expose zones of degraded quality in the centre to eastward parts. The spatial and temporal variations of CCME WQI classes and different physicochemical attributes indicated the influence of common factors attributing to the deep groundwater quality. The study also revealed inland salinity at Kolluparamba and Peruvamba stations, where agricultural activities were rampant with poor surface water irrigation.     

Acknowledgement of reviewers for 2020

Environmental Fluid Mechanics -     

Habitat,movements and environmental preferences of dusky sharks,Carcharhinus obscurus,in the northern Gulf of Mexico

The dusky shark (Carcharhinus obscurus) is the largest member of the genus Carcharhinus and inhabits coastal and pelagic ecosystems circumglobally in temperate, subtropical and tropical marine waters. In the western North Atlantic Ocean (WNA), dusky sharks are overfished and considered vulnerable by the International Union for the Conservation of Nature. As a result, retention of dusky sharks in commercial and recreational fisheries off the east coast of the United States (US) and in the northern Gulf of Mexico is prohibited. Despite the concerns regarding the status of dusky sharks in the WNA, little is known about their habitat utilization. During the summers of 2008–2009, pop-up satellite archival tags were attached to ten dusky sharks (one male, nine females) at a location where they have been observed to aggregate in the north central Gulf of Mexico southwest of the Mississippi River Delta to examine their movement patterns and habitat utilization. All tags successfully transmitted data with deployment durations ranging from 6 to 124 days. Tag data revealed shark movements in excess of 200 km from initial tagging locations, with sharks primarily utilizing offshore waters associated with the continental shelf edge from Desoto Canyon to the Texas/Mexican border. While most sharks remained in US waters, one individual moved from the northern Gulf of Mexico into the Bay of Campeche off the coast of Mexico. Sharks spent 87 % of their time between 20 and 125 m and 83 % of their time in waters between 23 and 30 °C. Since dusky sharks are among the most vulnerable shark species to fishing mortality, there is a recovery plan in place for US waters; however, since they have been shown to make long-distance migrations, a multi-national management plan within the WNA may be needed to ensure the successful recovery of this population.     

High male reproductive success in a low-density Antarctic fur seal (Arctocephalus gazella) breeding colony

Understanding how population density influences mating systems may lead to important insights into the plasticity of breeding behavior, but few natural systems allow for such studies. Antarctic fur seals (Arctocephalus gazella) provide an interesting model system because they breed in colonies of varying densities. Previous studies have largely focused on a high-density site at Bird Island, South Georgia. Here, 13 highly polymorphic microsatellite loci were used to conduct a genetic analysis of a low-density breeding colony of this species at Livingston Island, approximately 1,600 km south of South Georgia. The majority of adults seen ashore (n?=?54) were sampled together with every pup born (n?=?97) over four consecutive years. Paternities were confidently assigned for 34 out of the 97 pups. Two out of 23 sampled males accounted for the paternity of 28 % of all pups sampled during the study and 82 % of the pups with an assigned father. Moreover, a full likelihood pedigree inference method assigned a further eight paternities to a single unsampled male seal that is inferred to have held a territory during the season before the study began. The most successful males in our study easily surpassed the previous record for the total number of pups sired per male seal for the species. Furthermore, we identified two triads of full siblings implying that their parents remated in three consecutive years. These findings suggest that territorial male fur seals may achieve greater success in monopolizing access to breeding females when population density is relatively low.     

Model selection criteria for overdispersed data and their application to the characterization of a host-parasite relationship

In the statistical modeling of a biological or ecological phenomenon, selecting an optimal model among a collection of candidates is a critical issue. To identify an optimal candidate model, a number of model selection criteria have been developed and investigated based on estimating Kullback’s (Information theory and statistics. Dover, Mineola, 1968) directed or symmetric divergence. Criteria that target the directed divergence include the Akaike (2nd international symposium on information theory. Akadémia Kiadó, Budapest, Hungary, pp 267–281, 1973, IEEE Trans Autom Control AC 19:716–723, 1974) information criterion, AIC, and the “corrected” Akaike information criterion (Hurvich and Tsai in Biometrika 76:297–307, 1989), AICc; criteria that target the symmetric divergence include the Kullback information criterion, KIC, and the “corrected” Kullback information criterion, KICc (Cavanaugh in Stat Probab Lett 42:333–343, 1999; Aust N Z J Stat 46:257–274, 2004). For overdispersed count data, simple modifications of AIC and AICc have been increasingly utilized: specifically, the quasi Akaike information criterion, QAIC, and its corrected version, QAICc (Lebreton et al. in Ecol Monogr 62(1):67–118 1992). In this paper, we propose analogues of QAIC and QAICc based on estimating the symmetric as opposed to the directed divergence: QKIC and QKICc. We evaluate the selection performance of AIC, AICc, QAIC, QAICc, KIC, KICc, QKIC, and QKICc in a simulation study, and illustrate their practical utility in an ecological application. In our application, we use the criteria to formulate statistical models of the tick (Dermacentor variabilis) load on a white-footed mouse (Peromyscus leucopus) in northern Missouri.     

Numerical modelling of horizontal sediment-laden jets

Sediment-laden turbulent flows are commonly encountered in natural and engineered environments. It is well known that turbulence generates fluctuations to the particle motion, resulting in modulation of the particle settling velocity. A novel stochastic particle tracking model is developed to predict the particle settling out and deposition from a sediment-laden jet. Particle velocity fluctuations in the jet flow are modelled from a Lagrangian velocity autocorrelation function that incorporates the physical mechanism leading to a reduction of settling velocity. The model is first applied to study the settling velocity modulation in a homogeneous turbulence field. Consistent with basic experiments using grid-generated turbulence and computational fluid dynamics (CFD) calculations, the model predicts that the apparent settling velocity can be reduced by as much as 30 % of the stillwater settling velocity. Using analytical solution for the jet mean flow and semi-empirical RMS turbulent velocity fluctuation and dissipation rate profiles derived from CFD predictions, model predictions of the sediment deposition and cross-sectional concentration profiles of horizontal sediment-laden jets are in excellent agreement with data. Unlike CFD calculations of sediment fall out and deposition from a jet flow, the present method does not require any a priori adjustment of particle settling velocity.     

Effect of curacron toxicity on the total serum protein content of Cyprinus carpio

An experiment was conducted on freshwater fish Cyprinus carpio to study the effect of the pesticide curacron on total serum protein. Curacron is an organophosphate pesticide and used by the farmers to protect their crops. This pesticide reaches the aquatic ecosystem by direct or indirect means and affects aquatic fauna. LC50 for curacron for C. carpio was calculated by the log-dose/probit regression line method and found to be 0.38?ppm at 96?h. Three sub-lethal concentrations (0.1, 0.01, and 0.001?mL?L^?1) were selected to expose the fish for 1, 7, 14, and 21days. Changes in total serum protein were observed at all pesticide concentrations and exposure periods. Total serum protein was decreased from control. At 1 and 7 days, the decrease was quantitative at all concentrations, while at 14 and 21 days, the fall was significant at all concentrations. Hence, human population may be at risk by consuming these contaminated fish.     

Possible health impacts of naturally occurring uptake of aristolochic acids by maize and cucumber roots: links to the etiology of endemic (Balkan) nephropathy

Aristolochic acids (AAs) are nephrotoxic and carcinogenic derivatives found in several Aristolochia species. To date, the toxicity of AAs has been inferred only from the effects observed in patients suffering from a kidney disease called “aristolochic acid nephropathy” (AAN, formerly known as “Chinese herbs nephropathy”). More recently, the chronic poisoning with Aristolochia seeds has been considered to be the main cause of Balkan endemic nephropathy, another form of chronic renal failure resembling AAN. So far, it was assumed that AAs can enter the human food chain only through ethnobotanical use (intentional or accidental) of herbs containing self-produced AAs. We hypothesized that the roots of some crops growing in fields where Aristolochia species grew over several seasons may take up certain amounts of AAs from the soil, and thus become a secondary source of food poisoning. To verify this possibility, maize plant (Zea mays) and cucumber (Cucumis sativus) were used as a model to substantiate the possible significance of naturally occurring AAs’ root uptake in food chain contamination. This study showed that the roots of maize plant and cucumber are capable of absorbing AAs from nutrient solution, consequently producing strong peaks on ultraviolet HPLC chromatograms of plant extracts. This uptake resulted in even higher concentrations of AAs in the roots compared to the nutrient solutions. To further validate the measurement of AA content in the root material, we also measured their concentrations in nutrient solutions before and after the plant treatment. Decreased concentrations of both AAI and AAII were found in nutrient solutions after plant growth. During this short-term experiment, there were much lower concentrations of AAs in the leaves than in the roots. The question is whether these plants are capable of transferring significant amounts of AAs from the roots into edible parts of the plant during prolonged experiments.