The influence of winter water on phytoplankton blooms in the Chukchi Sea

Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 118 (2015): 53-72, doi:10.1016/j.dsr2.2015.06.006.The flow of nutrient-rich winter water (WW) through the Chukchi Sea plays an important and previously uncharacterized role in sustaining summer phytoplankton blooms. Using hydrographic and biogeochemical data collected as part of the ICESCAPE program (June-July 2010-11), we examined phytoplankton bloom dynamics in relation to the distribution and circulation of WW (defined as water with potential temperature ≤ -1.6°C) across the Chukchi shelf. Characterized by high concentrations of nitrate (mean: 12.3 ± 5.13 μmol L-1) that typically limits primary production in this region, WW was correlated with extremely high phytoplankton biomass, with mean chlorophyll a concentrations that were three-fold higher in WW (8.64 ± 9.75 μg L-1) than in adjacent warmer water (2.79 ± 5.58 μg L-1). Maximum chlorophyll a concentrations (~30 μg L-1) were typically positioned at the interface between nutrient-rich WW and shallower, warmer water with more light availability. Comparing satellite-based calculations of open water duration to phytoplankton biomass, nutrient concentrations, and oxygen saturation revealed widespread evidence of under-ice blooms prior to our sampling, with biogeochemical properties indicating that blooms had already terminated in many places where WW was no longer present. Our results suggest that summer phytoplankton blooms are sustained for a longer duration along the pathways of nutrient-rich WW and that biological hotspots in this region (e.g. the mouth of Barrow Canyon) are largely driven by the flow and confluence of these extremely productive pathways of WW that flow across the Chukchi shelf.This material is based upon work supported by the National Aeronautic and Space Administration (NASA) under Grant No. NNX10AF42G and the National Science Foundation Graduate Research Fellowship under Grant No. DGE-0645962 to K.E. Lowry

Deep borehole disposal of nuclear waste: US perspective

Radioactive waste disposal in deep boreholes may be more "ready" than disposal in mined geologic repositories since mankind has greater experience operating small deep holes - boreholes, than big shallow holes - mines. There are several thousand precedents for constructing >2 km deep boreholes and several hundred precedents for disposing long-lived wastes in boreholes. Borehole disposal is likely to be faster, cheaper, and more flexible than mined disposal, while also offering greater long-term isolation. Isolation would rely on the great depth, water density gradients, and reducing conditions to prevent vertical movement of waste up the borehole.Comment: 24 pages, 8 figure

Longitudinal Homogenization of the Microbiome between Both Occupants and the Built Environment in a Cohort of United States Air Force Cadets

The microbiome of the built environment has important implications for human health and wellbeing; however, bidirectional exchange of microbes between occupants and surfaces can be confounded by lifestyle, architecture, and external environmental exposures. Here, we present a longitudinal study of United States Air Force Academy cadets (n = 34), which have substantial homogeneity in lifestyle, diet, and age, all factors that influence the human microbiome. We characterized bacterial communities associated with (1) skin and gut samples from roommate pairs, (2) four built environment sample locations inside the pairs’ dormitory rooms, (3) four built environment sample locations within shared spaces in the dormitory, and (4) room-matched outdoor samples from the window ledge of their rooms

Improving drought and salinity tolerance in barley by application of salicylic acid and potassium nitrate

AbstractGrowth and physiological activities of barley (Hordeum vulgare L. cv. Gustoe) grown in soil cultures were evaluated to recognize the ameliorative role of salicylic acid (SA) and KNO3 against the negative effects of salt and water deficit stresses. Barley plants were subjected to three levels of NaCl (50, 100 and 150mM), three levels of water stress (80%, 70% and 50% of the soil water content (SWC) and the combination of 150mM NaCl+50μM SA, 150mM NaCl+10mM KNO3, 50% SWC+50μM SA and 50% SWC+10mM KNO3 for two weeks. Salt and water deficit stresses reduced the shoot growth, leaf photosynthetic pigments, K+ contents and provoked oxidative stress in leaves confirmed by considerable changes in soluble carbohydrate, proline, malondialdehyde (MDA), total phenolic compounds, antioxidant activity and Na+ contents. Leaf soluble protein of salt and water deficit treated plants was unaffected. The Na+/K+ ratio increased with increasing salt and water deficit treated plants. Application of 50μM SA or 10mM KNO3 to150mM NaCl and/or 50% SWC treated plants improved these attributes under salt and water stresses. Soluble carbohydrates in stressed plants may have a significant role in osmotic adjustment. It can be concluded that the addition of SA or KNO3 can ameliorate the oxidative stress in barley stressed plants. This ameliorative effect might be maintained through low MDA contents and decreased Na+/K+ ratio in leaves. This study also provided evidence for the ability of barley cultivation in salt and water deficit soils due to its capacity for osmotic adjustment

Environmental monitoring : phase 5 final report (April 2019 - March 2020)

This report presents the results and interpretation for Phase 5 of an integrated environmental monitoring programme that is being undertaken around two proposed shale gas sites in England – Preston New Road, Lancashire and Kirby Misperton, North Yorkshire. The report should be read in conjunction with previous reports freely available through the project website1 . These provide additional background to the project, presentation of earlier results and the rationale for establishment of the different elements of the monitoring programme

Assessing bird exclusion effects in a wetland crossed by a railway (Sado estuary, Portugal)

L. Borda-de-Água et al. (eds.), Railway Ecology, Chapter 11, p. 179-195Linear transportation infrastructures may displace wildlife from nearby areas that otherwise would provide adequate habitat conditions. This exclusion effect has been documented in roads, but much less is known about railways. Here we evaluated the potential exclusion effect on birds of a railway crossing a wetland of international importance (Sado Estuary, Portugal). We selected 22 sectors representative of locally available wetland habitats (salt pans, rice paddy fields, and intertidal mudflats); of each, half were located either close to (0–500 m) or far from (500–1500 m) the railway line. Water birds were counted in each sector between December 2012 and October 2015, during two months per season (spring, summer, winter, and autumn) and year, at both low and high tide. We recorded 46 species, of which the most abundant (>70% of individuals) were black-headed gull, greater flamingo, northern shoveler, black-tailed godwit, and lesser black-backed gull. Peak abundances were found in autumn and winter. There was no significant variation between sectors close to and far from the railway in species richness, total abundance, and abundance of the most common species. Some species tended to be most abundant either close to or far from the railway albeit not significantly so but this often varied across the tidal and annual cycles. Overall, our study did not find noticeable exclusion effects of this railway on wetland birds, with spatial variation in abundances probably reflecting habitat selection and daily movement patterns. Information is needed on other study systems to assess the generality of our findingsinfo:eu-repo/semantics/publishedVersio

Ground beetles in city forests: does urbanization predict a personality trait?

Background. Urbanization leads to substantial changes in natural habitats with profound effects on wildlife. Understanding behavioural responses to such environmental change is essential for identifying which organisms may adapt, as behaviour is often the first response to altered conditions. Individuals in more urbanized habitats may be expected to be more exploratory and bolder than their conspecifics in less urbanized habitats as they may be better able to cope with novel challenges. Methods. In a two-year field study we tested ground beetles from differently urbanized forests for their exploratory behaviour (in a novel environment) and their risk-taking (death-feigning). In total, we tested ca. 3,000 individuals of four forest-dwelling ground beetle species from eight within-city forest patches. In the second year, we also transferred ca. 800 tested individuals of two species to the laboratory to test for consistent behavioural differences (i.e. personality differences) under standardised conditions. Results. Individuals were generally more exploratory in more urbanized than in less urbanized areas but only in one year of the study. Exploratory behaviour was not predicted by population density but increased with temperature or showed a temperature optimum. Exploration was consistent over time and individuals that were more exploratory also took higher risks. Discussion. We demonstrated that species which are generally less directly exposed to human activities (e.g., most invertebrates) show behavioural responses to urbanization. Effects of urbanization were year-dependent, suggesting that other environmental conditions interacted with effects of urbanization on beetle behaviour. Furthermore, our results indicate that different personality compositions might cause behavioural differences among populations living in differently urbanized habitats

Solubilization and partial purification of dihydroxyacetone-phosphate acyltransferase from guinea pig liver

Dihydroxyacetone-phosphate:acyl coenzyme A acyltransferase (EC 2.3.1.42) was solubilized and partially purified from guinea pig liver crude peroxisomal fraction. The peroxisomal membrane was isolated after osmotic shock treatment and the bound dihydroxyacetone-phosphate acyltransferase was solubilized by treatment with a mixture of KCl-sodium cholate. The solubilized enzyme was partially purified by ammonium sulfate fractionation followed by Sepharose 6B gel filtration. The enzyme was purified 1200-fold relative to the guinea pig liver homogenate and 80- to 100-fold from the crude peroxisomal fraction, with an overall yield of 25-30% from peroxisomes. The partially purified enzyme was stimulated two- to fourfold by Asolectin (a soybean phospholipid preparation), and also by individual classes of phospholipid such as phosphatidylcholine and phosphatidylglycerol. The kinetic properties of the enzyme showed that in the absence of Asolectin there was a discontinuity in the reciprocal plot indicating two different apparent Km values (0.1 and 0.5 mm) for dihydroxyacetone phosphate. The Vmax was 333 nmol/min/mg protein. In the presence of Asolectin the reciprocal plot was linear, with a Km = 0.1 mm and no change in Vmax. The enzyme catalyzed both an exchange of acyl groups between dihydroxyacetone phosphate and palmitoyl dihydroxyacetone phosphate in the presence of CoA and the formation of palmitoyl [3H]coenzyme A from palmitoyl dihydroxyacetone phosphate and [3H]coenzyme A, indicating that the reaction is reversible. The partially purified enzyme preparation had negligible glycerol-3-phosphate acyltransferase (EC 2.3.1.15) activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25098/1/0000530.pd