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https://www.readbyqxmd.com/read/28088697/vertical-distribution-of-236-u-in-the-north-pacific-ocean
#1
R Eigl, P Steier, K Sakata, A Sakaguchi
The first extensive study on (236)U in the North Pacific Ocean has been conducted. The vertical distribution of (236)U/(238)U isotopic ratios and the (236)U concentrations were analysed on seven depth profiles, and large variations with depth were found. The range of (236)U/(238)U isotopic ratios was from (0.09 ± 0.03) × 10(-10) to (14.1 ± 2.2) × 10(-10), which corresponds to (236)U concentrations of (0.69 ± 0.24) × 10(5) atoms/kg and (119 ± 21) × 10(5) atoms/kg, respectively. The variations in (236)U concentrations could mainly be attributed to the different water masses in the North Pacific Ocean and their formation processes...
January 12, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28088543/transformation-of-terrestrial-organic-matter-along-thermokarst-affected-permafrost-coasts-in-the-arctic
#2
George Tanski, Hugues Lantuit, Saskia Ruttor, Christian Knoblauch, Boris Radosavljevic, Jens Strauss, Juliane Wolter, Anna M Irrgang, Justine Ramage, Michael Fritz
The changing climate in the Arctic has a profound impact on permafrost coasts, which are subject to intensified thermokarst formation and erosion. Consequently, terrestrial organic matter (OM) is mobilized and transported into the nearshore zone. Yet, little is known about the fate of mobilized OM before and after entering the ocean. In this study we investigated a retrogressive thaw slump (RTS) on Qikiqtaruk - Herschel Island (Yukon coast, Canada). The RTS was classified into an undisturbed, a disturbed (thermokarst-affected) and a nearshore zone and sampled systematically along transects...
January 11, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28088495/interaction-strength-between-different-grazers-and-macroalgae-mediated-by-ocean-acidification-over-warming-gradients
#3
E Sampaio, I F Rodil, F Vaz-Pinto, A Fernández, F Arenas
Since the past century, rising CO2 levels have led to global changes (ocean warming and acidification) with subsequent effects on marine ecosystems and organisms. Macroalgae-herbivore interactions have a main role in the regulation of marine community structure (top-down control). Gradients of warming prompt complex non-linear effects on organism metabolism, cascading into altered trophic interactions and community dynamics. However, not much is known on how will acidification and grazer assemblage composition shape these effects...
January 6, 2017: Marine Environmental Research
https://www.readbyqxmd.com/read/28088370/predator-prey-interaction-between-muricid-gastropods-and-mussels-under-ocean-acidification
#4
X-Y Xu, K R Yip, P K S Shin, S G Cheung
Predation of the muricid gastropod Thais clavigera on two-sized groups of the mussel Brachidontes variabilis was studied under three pCO2 levels, 380, 950, and 1250μatm. At 950μatm pCO2 level, the prey handling time decreased significantly and large-sized B. variabilis were preferred by T. clavigera. However, the prey consumption rate was independent of pCO2 levels, although the prey searching time increased significantly at elevated pCO2. These findings indicated that the predator-prey interaction between T...
January 11, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28088106/uv-a-induced-delayed-development-in-the-larvae-of-coral-seriatopora-caliendrum
#5
Jie Zhou, Tung-Yung Fan, John Beardall, Kunshan Gao
Coral reefs are vulnerable to ultraviolet radiation (UVR, 280-400nm). Not only do the fluxes of UVR fluctuate daily, they are also increasing due to global ocean and atmospheric changes. The deleterious effects of UVR on scleractinian corals have been intensively studied, but much less is known about the response of corals in the early pre-settlement phase. In this study, we tested how UVR exposure affects survival and development of Seriatopora caliendrum larvae and examined the photophysiological changes induced in the symbiotic dinoflagellate Symbiodinium...
January 4, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28087656/conspecific-aggregations-mitigate-the-effects-of-ocean-acidification-on-calcification-of-the-coral-pocillopora-verrucosa
#6
Nicolas R Evensen, Peter J Edmunds
In densely populated communities, such as coral reefs, organisms can modify the physical and chemical environment for neighbouring individuals. We tested the hypothesis that colony density (12 colonies each placed∼0.5 cm apart versus∼8 cm apart) can modulate the physiological response (measured through rates of calcification, photosynthesis, and respiration in the light and dark) of the coral Pocillopora verrucosa to pCO2 treatments (∼ 400 µatm and∼1200 µatm) by altering the seawater flow regimes experienced by colonies placed in aggregations within a flume at a single flow speed...
January 13, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28087525/capturing-compositional-variation-in-denitrifying-communities-a-multiple-primer-approach-that-includes-autotrophic-denitrifying-epsilonproteobacteria
#7
Sheryl A Murdock, S Kim Juniper
: Denitrifying Epsilonproteobacteria may dominate nitrogen loss processes in marine habitats with intense redox gradients but assessment of their importance is limited by currently available primers for nitrite reductase genes. Nine new primers targeting the nirS gene of denitrifying Epsilonproteobacteria were designed and tested for use in sequencing and quantitative PCR on two microbial mat samples (Vent 2 and Vent 4) from the Calypso hydrothermal vent field, Bay of Plenty, New Zealand...
January 13, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28087421/physiology-anaerobes-and-the-origin-of-mitosing-cells-50-years-on
#8
William F Martin
Endosymbiotic theory posits that some organelles or structures of eukaryotic cells stem from free-living prokaryotes that became endosymbionts within a host cell. Endosymbiosis has a long and turbulent history of controversy and debate going back over 100 years. The 1967 paper by Lynn Sagan (later Lynn Margulis) forced a reluctant field to take endosymbiotic theory seriously and to incorporate it into the fabric of evolutionary thinking. Margulis envisaged three cellular partners associating in series at eukaryotic origin: the host (an engulfing bacterium), the mitochondrion (a respiring bacterium), and the flagellum (a spirochaete), with lineages descended from that flagellated eukaryote subsequently acquiring plastids from cyanobacteria, but on multiple different occasions in her 1967 account...
January 10, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28086785/whole-genome-resequencing-reveals-diagnostic-markers-for-investigating-global-migration-and-hybridization-between-minke-whale-species
#9
Ketil Malde, Bjørghild B Seliussen, María Quintela, Geir Dahle, Francois Besnier, Hans J Skaug, Nils Øien, Hiroko K Solvang, Tore Haug, Rasmus Skern-Mauritzen, Naohisa Kanda, Luis A Pastene, Inge Jonassen, Kevin A Glover
BACKGROUND: In the marine environment, where there are few absolute physical barriers, contemporary contact between previously isolated species can occur across great distances, and in some cases, may be inter-oceanic. An example of this can be seen in the minke whale species complex. Antarctic minke whales are genetically and morphologically distinct from the common minke found in the north Atlantic and Pacific oceans, and the two species are estimated to have been isolated from each other for 5 million years or more...
January 13, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28081236/a-key-marine-diazotroph-in-a-changing-ocean-the-interacting-effects-of-temperature-co2-and-light-on-the-growth-of-trichodesmium-erythraeum-ims101
#10
Tobias G Boatman, Tracy Lawson, Richard J Geider
Trichodesmium is a globally important marine diazotroph that accounts for approximately 60 - 80% of marine biological N2 fixation and as such plays a key role in marine N and C cycles. We undertook a comprehensive assessment of how the growth rate of Trichodesmium erythraeum IMS101 was directly affected by the combined interactions of temperature, pCO2 and light intensity. Our key findings were: low pCO2 affected the lower temperature tolerance limit (Tmin) but had no effect on the optimum temperature (Topt) at which growth was maximal or the maximum temperature tolerance limit (Tmax); low pCO2 had a greater effect on the thermal niche width than low-light; the effect of pCO2 on growth rate was more pronounced at suboptimal temperatures than at supraoptimal temperatures; temperature and light had a stronger effect on the photosynthetic efficiency (Fv/Fm) than did CO2; and at Topt, the maximum growth rate increased with increasing CO2, but the initial slope of the growth-irradiance curve was not affected by CO2...
2017: PloS One
https://www.readbyqxmd.com/read/28081121/isolation-of-novel-trypanosomatid-zelonia-australiensis-sp-nov-kinetoplastida-trypanosomatidae-provides-support-for-a-gondwanan-origin-of-dixenous-parasitism-in-the-leishmaniinae
#11
Joel Barratt, Alexa Kaufer, Bryce Peters, Douglas Craig, Andrea Lawrence, Tamalee Roberts, Rogan Lee, Gary McAuliffe, Damien Stark, John Ellis
The genus Leishmania includes approximately 53 species, 20 of which cause human leishmaniais; a significant albeit neglected tropical disease. Leishmaniasis has afflicted humans for millennia, but how ancient is Leishmania and where did it arise? These questions have been hotly debated for decades and several theories have been proposed. One theory suggests Leishmania originated in the Palearctic, and dispersed to the New World via the Bering land bridge. Others propose that Leishmania evolved in the Neotropics...
January 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28081120/epidemiology-of-chikungunya-virus-outbreaks-in-guadeloupe-and-martinique-2014-an-observational-study-in-volunteer-blood-donors
#12
Pierre Gallian, Isabelle Leparc-Goffart, Pascale Richard, Françoise Maire, Olivier Flusin, Rachid Djoudi, Jacques Chiaroni, Remi Charrel, Pierre Tiberghien, Xavier de Lamballerie
BACKGROUND: During Dec-2013, a chikungunya virus (CHIKV) outbreak was first detected in the French-West Indies. Subsequently, the virus dispersed to other Caribbean islands, continental America and many islands in the Pacific Ocean. Previous estimates of the attack rate were based on declaration of clinically suspected cases. METHODS/PRINCIPAL FINDINGS: Individual testing for CHIKV RNA of all (n = 16,386) blood donations between Feb-24th 2014 and Jan-31st 2015 identified 0·36% and 0·42% of positives in Guadeloupe and Martinique, respectively...
January 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28080914/tricaine-methanesulfonate-ms-222-sedation-and-anesthesia-in-the-purple-spined-sea-urchin-arbacia-punctulata
#13
Jeffrey R Applegate, Daniel S Dombrowski, Larry Shane Christian, Meredith P Bayer, Craig A Harms, Gregory A Lewbart
The purple-spined sea urchin ( Arbacia punctulata ) is commonly found in shallow waters of the western Atlantic Ocean from the New England area of the United States to the Caribbean. Sea urchins play a major role in ocean ecology, echinoculture, and biomedical research. Additionally, sea urchins are commonly displayed in public aquaria. Baseline parameters were developed in unanesthetized urchins for righting reflex (time to regain oral recumbency) and spine response time to tactile stimulus. Tricaine methanesulfonate (MS-222) was used to sedate and anesthetize purple-spined sea urchins and assess sedation and anesthetic parameters, including adhesion to and release from a vertical surface, times to loss of response to tactile stimulus and recovery of righting reflex, and qualitative observations of induction of spawning and position of spines and pseudopodia...
December 2016: Journal of Zoo and Wildlife Medicine: Official Publication of the American Association of Zoo Veterinarians
https://www.readbyqxmd.com/read/28079106/extreme-mitochondrial-variation-in-the-atlantic-gall-crab-opecarcinus-hypostegus-decapoda-cryptochiridae-reveals-adaptive-genetic-divergence-over-agaricia-coral-hosts
#14
Kaj M van Tienderen, Sancia E T van der Meij
The effectiveness of migration in marine species exhibiting a pelagic larval stage is determined by various factors, such as ocean currents, pelagic larval stage duration and active habitat selection. Direct measurement of larval movements is difficult and, consequently, factors determining the gene flow patterns remain poorly understood for many species. Patterns of gene flow play a key role in maintaining genetic homogeneity in a species by dampening the effects of local adaptation. Coral-dwelling gall crabs (Cryptochiridae) are obligate symbionts of stony corals (Scleractinia)...
January 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28078797/in-situ-incubation-of-iron-sulfur-mineral-reveals-a-diverse-chemolithoautotrophic-community-and-a-new-biogeochemical-role-for-thiomicrospira
#15
Roman A Barco, Colleen L Hoffman, Gustavo A Ramírez, Brandy M Toner, Katrina J Edwards, Jason B Sylvan
Sulfide mineral precipitation occurs at mid-ocean ridge (MOR) spreading centers, both in the form of plume particles and seafloor massive sulfide structures. A common constituent of MOR is the iron-bearing sulfide mineral pyrrhotite, which was chosen as a substrate for in-situ incubation studies in shallow waters of Catalina Island, CA to investigate the colonization of iron-oxidizing bacteria. Microbial community datasets were obtained from in-situ incubated pyrrhotite, allowing for direct comparison to microbial communities of iron-sulfides from active and inactive chimneys in deep-sea environments...
January 12, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28078785/risks-of-ocean-acidification-in-the-california-current-food-web-and-fisheries-ecosystem-model-projections
#16
Kristin N Marshall, Isaac C Kaplan, Emma E Hodgson, Albert Hermann, D Shallin Busch, Paul McElhany, Timothy E Essington, Chris J Harvey, Elizabeth A Fulton
The benefits and ecosystem services that humans derive from the oceans are threatened by numerous global change stressors, one of which is ocean acidification. Here, we describe the effects of ocean acidification on an upwelling system that already experiences inherently low pH conditions, the California Current. We used an end-to-end ecosystem model (Atlantis), forced by downscaled global climate models and informed by a meta-analysis of the pH sensitivities of local taxa, to investigate the direct and indirect effects of future pH on biomass and fisheries revenues...
January 12, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28078522/long-term-impact-of-reduced-tillage-on-water-and-pesticide-flow-in-a-drained-context
#17
R Dairon, A Dutertre, J Tournebize, J Marks-Perreau, N Carluer
Influence of more than 20 years (1988-2010) of reduced tillage (RT) practices on water and pesticide balances and dynamics is analyzed and compared to results from a conventional tillage plot (CT). The field study soils are described as silty clay stagnic luvisol, developed on a low permeable schist layer. A drainage network was set up according to French criteria (0.9 m deep, 10 m space) to avoid soil winter waterlogging. Climate is temperate oceanic and drainage generally occurs from November to March...
January 11, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28078499/carbonaceous-chondrite-meteorites-the-chronicle-of-a-potential-evolutionary-path-between-stars-and-life
#18
Sandra Pizzarello, Everett Shock
The biogenic elements, H, C, N, O, P and S, have a long cosmic history, whose evolution can still be observed in diverse locales of the known universe, from interstellar clouds of gas and dust, to pre-stellar cores, nebulas, protoplanetary discs, planets and planetesimals. The best analytical window into this cosmochemical evolution as it neared Earth has been provided so far by the small bodies of the Solar System, some of which were not significantly altered by the high gravitational pressures and temperatures that accompanied the formation of larger planets and may carry a pristine record of early nebular chemistry...
January 11, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28078050/complete-genome-sequence-of-lutibacter-profundi-lp1-t-isolated-from-an-arctic-deep-sea-hydrothermal-vent-system
#19
Juliane Wissuwa, Sven Le Moine Bauer, Ida Helene Steen, Runar Stokke
Lutibacter profundi LP1(T) within the family Flavobacteriaceae was isolated from a biofilm growing on the surface of a black smoker chimney at the Loki's Castle vent field, located on the Arctic Mid-Ocean Ridge. The complete genome of L. profundi LP1(T) is the first genome to be published within the genus Lutibacter. L. profundi LP1(T) consists of a single 2,966,978 bp circular chromosome with a GC content of 29.8%. The genome comprises 2,537 protein-coding genes, 40 tRNA species and 2 rRNA operons. The microaerophilic, organotrophic isolate contains genes for all central carbohydrate metabolic pathways...
2017: Standards in Genomic Sciences
https://www.readbyqxmd.com/read/28077930/before-the-freeze-otoliths-from-the-eocene-of-seymour-island-antarctica-reveal-dominance-of-gadiform-fishes-teleostei
#20
Werner Schwarzhans, Thomas Mörs, Andrea Engelbrecht, Marcelo Reguero, Jürgen Kriwet
The first record of fossil teleostean otoliths from Antarctica is reported. The fossils were obtained from late Early Eocene shell beds of the La Meseta Formation, Seymour Island that represent the last temperate marine climate phase in Antarctica prior to the onset of cooling and subsequent glaciation during the late Eocene. A total of 17 otolith-based teleost taxa are recognized, with 10 being identifiable to species level containing nine new species and one new genus: Argentina antarctica sp. nov., Diaphus? marambionis sp...
2017: Journal of Systematic Palaeontology
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