SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Great Salt Lake

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This study sought to determine radiation exposure across the cranium of cardiologists and the protective ability of a nonlead, XPF (barium sulfate/bismuth oxide) layered cap (BLOXR, Salt Lake City, Utah) during fluoroscopically guided, invasive cardiovascular (CV) procedures.

Concepts: Salt Lake City International Airport, Real Salt Lake, Wasatch Front, Medicine, Salt Lake County, Utah, Utah, Great Salt Lake, Salt Lake City

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Chemical cues from fish, or kairomones, often impact the behavior of zooplankton. These behavioral changes are thought to improve predator avoidance. For example, marine and estuarine crustacean zooplankton become more sensitive to light after kairomone exposure, which likely deepens their vertical distribution into darker waters during the day and thereby reduces their visibility to fish predators. Here, we show that kairomones from an estuarine fish induce similar behavioral responses in adult brine shrimp (Artemia franciscana) from an endorheic, hypersaline lake, Great Salt Lake, Utah, USA. Given downwelling light stimuli, kairomone-exposed A. franciscana induce a descent response upon dimmer light flashes than they do in the absence of kairomones. Using extracellular electroretinogram (ERG) recordings, we also find that kairomones induce physiological changes in the retina that may lead to increased visual sensitivity, suggesting that kairomone-induced changes to photobehavior are mediated at the photoreceptor level. However, kairomones did not induce structural changes within the eye. Although A. franciscana inhabit endorheic environments that are too saline for most fish, kairomones from an estuarine fish amplify photobehavior in these branchiopod crustaceans. The mechanism for this behavioral change has both similarities to and differences from that described in marine malacostracan crustaceans.

Concepts: Krill, Great Salt Lake, Fairy shrimp, Branchiopoda, Brine shrimp, Mono Lake, Arthropod, Crustacean

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The oxygen (18O/16O) isotope analysis of hair is commonly applied to reconstruct an individual’s residence history. However, region-of-origin as determined from oxygen isotope values (δ18O) alone is often spatially indistinct. Adding additional geochemical recorders can refine region-of-origin estimates. In this capacity, strontium (87Sr/86Sr) isotope analysis has attracted increased interest. While87Sr/86Sr reflects the influences of local geology,87Sr/86Sr of hair includes both external environmental signals as well as the internal dietary indicators. To better understand the impact of these contributions to the spatial signal encoded within87Sr/86Sr of hair, human hair was collected from three locations within Salt Lake City, Utah along with the donor’s sex. The87Sr/86Sr and δ18O of hair and local tap water were measured. There were no significant relationships between sex and either δ18O or87Sr/86Sr of hair, nor between collection location and the δ18O of hair. However, we found significant associations between collection location and87Sr/86Sr of hair. These findings suggest that interactions with local water may be an important source of Sr to human hair and that the87Sr/86Sr of hair may have the capacity to record differences in87Sr/86Sr of tap waters on small spatial scales.

Concepts: Great Salt Lake, Pacific Coast League, Water supply, Water quality, Protein, Salt Lake City, Utah, Water

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Measurements of chemical and physical parameters made before and after sealing of culverts in the railroad causeway spanning Great Salt Lake in late 2013 documented dramatic alterations in the system in response to the elimination of flow between the Great Salt Lake’s north and south arms. The flow of denser, more saline water through the culverts from the north arm (Gunnison Bay) to the south arm (Gilbert Bay) previously drove the perennial stratification of the south arm and the existence of oxic shallow brine and anoxic deep brine layers. Closure of the causeway culverts occurred concurrently with a multiyear drought that resulted in a decrease in the lake elevation and a concomitant increase in top-down erosion of the upper surface of the deep brine layer by wind-forced mixing. The combination of these events resulted in replacement of the formerly stratified water column in the south arm with one that is vertically homogeneous and oxic. Total mercury concentrations in the deep waters of the south arm decreased by approximately 81%, and methylmercury concentrations in deep waters decreased by roughly 86%, due to destratification. Methylmercury concentrations decreased by 77% in underlying surficial sediment whereas there no change was observed in total mercury. The dramatic mercury loss from deep waters and methylmercury loss from underlying sediment in response to causeway sealing provides new understanding of the potential role of the deep brine layer in the accumulation and persistence of methylmercury in the Great Salt Lake. Additional mercury measurements in biota appear to contradict the previously implied connection between elevated methylmercury concentrations in the deep brine layer and elevated mercury in avian species reported prior to causeway sealing.

Concepts: Jordan River, Utah Lake, Salt Lake City, Lake, Utah, Water, Great Salt Lake

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Microbialites are widespread in modern and fossil hypersaline environments, where they provide a unique sedimentary archive. Authigenic mineral precipitation in modern microbialites results from a complex interplay between microbial metabolisms, organic matrices and environmental parameters. Here, we combined mineralogical and microscopic analyses with measurements of metabolic activity in order to characterise the mineralisation of microbial mats forming microbialites in the Great Salt Lake (Utah, USA). Our results show that the mineralisation process takes place in three steps progressing along geochemical gradients produced through microbial activity. First, a poorly crystallized Mg-Si phase precipitates on alveolar extracellular organic matrix due to a rise of the pH in the zone of active oxygenic photosynthesis. Second, aragonite patches nucleate in close proximity to sulfate reduction hotspots, as a result of the degradation of cyanobacteria and extracellular organic matrix mediated by, among others, sulfate reducing bacteria. A final step consists of partial replacement of aragonite by dolomite, possibly in neutral to slightly acidic porewater. This might occur due to dissolution-precipitation reactions when the most recalcitrant part of the organic matrix is degraded. The mineralisation pathways proposed here provide pivotal insight for the interpretation of microbial processes in past hypersaline environments.

Concepts: Utah, Fossil, Carbon dioxide, Water, Metabolism, Great Salt Lake, Bacteria, Photosynthesis

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We assessed effects on physical activity (PA) and weight among participants in a complete street intervention that extended a light-rail line in Salt Lake City, Utah.

Concepts: Wasatch Front, Obesity, Salt Lake County, Utah, Utah, Body mass index, Great Salt Lake, Mass, Salt Lake City

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Dunaliella, a commercially important chlorophyte, is globally distributed in saline habitats. Morphological species have not been definitively reconciled with phylogenetic analyses. Considerable genetic diversity continues to be discovered in new isolates, especially from soil and benthic habitats. Twenty-nine new isolates from Great Salt Lake, Utah, many from benthic or supralittoral habitats, were phylogenetically analyzed using ITS1+5.8S+ITS2 in comparison to a broad sampling of available sequences. A few new isolates align in one branch of a bifurcated monophyletic D. salina clade and several cluster within monophyletic D. viridis. Several others align with relatively few unnamed strains from other locations, comprising a diverse clade that may represent two or more new species. The overall Dunaliella clade is relatively robust, but the nearest outgroups are ambiguously placed with extremely long branches. About half of the isolates, all from benthic or supralittoral habitats, have been persistently sarcinoid in liquid media since isolation. This trait is spread across the Dunaliella phylogeny. The morphology of two sarcinoid strains was documented with light microscopy, revealing an extensive glycocalyx. Clumping behavior of unicellular and sarcinoid strains was unaffected by presence or absence of Mg2+ or Ca2+ , addition of lectin-inhibiting monosaccharides, or water-soluble factors from morphologically opposite strains. Results from this investigation have significantly expanded our current understanding of Dunaliella diversity, but it seems likely that much remains to be discovered with additional sampling. This article is protected by copyright. All rights reserved.

Concepts: Lake, Computational phylogenetics, Great Salt Lake, Polyphyly, Cladistics, Phylogenetic nomenclature, Species, Phylogenetics

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Editor’s note: On July 26, 2017, Alex Wubbels, the charge nurse on the burn unit at the University of Utah Hospital in Salt Lake City, was arrested for refusing to allow a police officer to draw blood from an unconscious patient in her care. Her arrest, during which she was forcefully placed in handcuffs and dragged out of the hospital, was documented on body camera video and drew national attention. We asked our ethical and legal contributing editors to provide some insight on the issues of this case.

Concepts: UTA TRAX, Fort Douglas, Utah, Police, Pioneer Theatre Company, Great Salt Lake, University of Utah, Utah, Salt Lake City

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Managers of invasive species consider the peer-reviewed literature only moderately helpful for guiding their management programs. Though this “knowing-doing gap” has been well-described, there have been few efforts to guide scientists in how to develop useful and usable science. Here we demonstrate how a comprehensive survey of managers (representing 42 wetland management units across the Great Salt Lake watershed) can highlight management practices and challenges (here for the widespread invasive plant, Phragmites australis, a recent and aggressive invader in this region) to ultimately inform a research program. The diversity of surveyed organizations had wide-ranging amounts of Phragmites which led to different goals and approaches including more aggressive control targets and a wider array of control tools for smaller, private organizations compared to larger government-run properties. We found that nearly all managers (97%) used herbicide as their primary Phragmites control tool, while burning (65%), livestock grazing (49%), and mowing (43%) were also frequently used. Managers expressed uncertainties regarding the timing of herbicide application and type of herbicide for effective control. Trade-offs between different Phragmites treatments were driven by budgetary concerns, as well as environmental conditions like water levels and social constraints like permitting issues. Managers had specific ideas about the plant communities they desired following Phragmites control, yet revegetation of native species was rarely attempted. The results of this survey informed the development of large-scale, multi-year Phragmites control and native plant revegetation experiments to address management uncertainties regarding herbicide type and timing. The survey also facilitated initial scientist-manager communication, which led to collaborations and knowledge co-production between managers and researchers. An important outcome of the survey was that experimental results were more pertinent to manager needs and trusted by managers. Such an approach that integrates manager surveys to inform management experiments could be adapted to any developing research program seeking to be relevant to management audiences.

Concepts: Genetic pollution, Geodesy, Invasive species, Surveying, Introduced species, Weed, Great Salt Lake, Management