Read by QxMD icon Read


Aaron J Berliner, Tomohiro Mochizuki, Kenneth M Stedman
Viruses are the most abundant biological entities on modern Earth. They are highly diverse both in structure and genomic sequence, play critical roles in evolution, strongly influence terran biogeochemistry, and are believed to have played important roles in the origin and evolution of life. However, there is yet very little focus on viruses in astrobiology. Viruses arguably have coexisted with cellular life-forms since the earliest stages of life, may have been directly involved therein, and have profoundly influenced cellular evolution...
January 10, 2018: Astrobiology
Tyler Cyronak, Andreas J Andersson, Chris Langdon, Rebecca Albright, Nicholas R Bates, Ken Caldeira, Renee Carlton, Jorge E Corredor, Rob B Dunbar, Ian Enochs, Jonathan Erez, Bradley D Eyre, Jean-Pierre Gattuso, Dwight Gledhill, Hajime Kayanne, David I Kline, David A Koweek, Coulson Lantz, Boaz Lazar, Derek Manzello, Ashly McMahon, Melissa Meléndez, Heather N Page, Isaac R Santos, Kai G Schulz, Emily Shaw, Jacob Silverman, Atsushi Suzuki, Lida Teneva, Atsushi Watanabe, Shoji Yamamoto
Worldwide, coral reef ecosystems are experiencing increasing pressure from a variety of anthropogenic perturbations including ocean warming and acidification, increased sedimentation, eutrophication, and overfishing, which could shift reefs to a condition of net calcium carbonate (CaCO3) dissolution and erosion. Herein, we determine the net calcification potential and the relative balance of net organic carbon metabolism (net community production; NCP) and net inorganic carbon metabolism (net community calcification; NCC) within 23 coral reef locations across the globe...
2018: PloS One
Gabrijel Ondrasek, Zed Rengel, Davor Romic
Naturally-occurring highly-complexed and polymerised organics such as humic acids (HA), due to their large negative charge, play a crucial role in biogeochemistry of trace metals (TM). Toxic (Cd) as well as essential (Zn, Cu, Mn) TM bind strongly to HA, but how these organo-metalic forms influence metal uptake by plants is poorly understood. A solution culture study was conducted to characterize the effects of different concentrations of HA (0-225mg/L) on the growth and element uptake/distribution in roots, shoots and hypocotyls of radish (Raphanus sativus L...
January 3, 2018: Ecotoxicology and Environmental Safety
Rafael Gonçalves-Araujo, Benjamin Rabe, Ilka Peeken, Astrid Bracher
As consequences of global warming sea-ice shrinking, permafrost thawing and changes in fresh water and terrestrial material export have already been reported in the Arctic environment. These processes impact light penetration and primary production. To reach a better understanding of the current status and to provide accurate forecasts Arctic biogeochemical and physical parameters need to be extensively monitored. In this sense, bio-optical properties are useful to be measured due to the applicability of optical instrumentation to autonomous platforms, including satellites...
2018: PloS One
Jun-Jian Wang, Melissa Lafrenière, Scott Lamoureux, Andre J Simpson, Yves Gélinas, Myrna J Simpson
Regional warming has caused permafrost thermokarst and disturbances, such as active layer detachments (ALDs), which may alter carbon feedback in Arctic ecosystems. However, it is currently unclear how these disturbances alter DOM biogeochemistry in rivers and ponds in Arctic ecosystems. Water samples from main channel, ALD-disturbed/undisturbed tributaries, and disturbed/undisturbed ponds within a catchment of Canadian High Arctic were collected and analyzed using carbon isotopes and spectroscopic methods. Both river and pond samples had large variations in dissolved organic carbon (DOC) concentrations...
January 4, 2018: Environmental Science & Technology
William M Balch
Coccolithophores are major contributors to phytoplankton communities and ocean biogeochemistry and are strong modulators of the optical field in the sea. New discoveries are changing paradigms about these calcifiers. A new role for silicon in coccolithophore calcification is coupling carbonate and silicon cycles. Phosphorus and iron play key roles in regulating coccolithophore growth. Comparing molecular phylogenies with coccolith morphometrics is forcing the reconciliation of biological and geological observations...
January 3, 2018: Annual Review of Marine Science
David J Augustine, Dana M Blumenthal, Tim L Springer, Daniel R LeCain, Stacey A Gunter, Justin D Derner
Increasing atmospheric [CO2 ] and temperature are expected to affect the productivity, species composition, biogeochemistry, and therefore the quantity and quality of forage available to herbivores in rangeland ecosystems. Both elevated CO2 (eCO2 ) and warming affect plant tissue chemistry through multiple direct and indirect pathways, such that the cumulative outcomes of these effects are difficult to predict. Here, we report on a 7-year study examining effects of CO2 enrichment (to 600 ppm) and infrared warming (+1...
January 3, 2018: Ecological Applications: a Publication of the Ecological Society of America
Jennifer Hellal, André Burnol, Aude Locatelli, Fabienne Battaglia-Brunet
Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as redox potential (Eh) and pH, but also to microbial activities that can play a direct or indirect role on speciation and/or mobility. Indeed, some bacteria can directly oxidize As(III) to As(V) or reduce As(V) to As(III). Likewise, bacteria are strongly involved in Hg cycling, either through its methylation, forming the neurotoxin monomethyl mercury, or through its reduction to elemental Hg°...
December 19, 2017: Journal of Visualized Experiments: JoVE
Sara J Klapstein, Nelson J O'Driscoll
Mercury contamination is a growing concern for freshwater food webs in ecosystems without point sources of mercury. Methylmercury (MeHg) is of particular concern, as this is the form of mercury that crosses the blood-brain barrier and is neurotoxic to organisms. Wetlands and benthic sediments have high organic content and low oxygen availability. Anaerobic bacteria drive the metabolic function in these ecosystems and subsequently can methylate mercury. The bioavailability of MeHg is controlled by physicochemical characteristics such as pH, binding affinities, and dissolved organic matter (DOM)...
December 16, 2017: Bulletin of Environmental Contamination and Toxicology
Etienne Low-Décarie, Tobias G Boatman, Noah Bennett, Will Passfield, Antonio Gavalás-Olea, Philipp Siegel, Richard J Geider
The equations used to account for the temperature dependence of biological processes, including growth and metabolic rates, are the foundations of our predictions of how global biogeochemistry and biogeography change in response to global climate change. We review and test the use of 12 equations used to model the temperature dependence of biological processes across the full range of their temperature response, including supra- and suboptimal temperatures. We focus on fitting these equations to thermal response curves for phytoplankton growth but also tested the equations on a variety of traits across a wide diversity of organisms...
December 2017: Ecology and Evolution
Heather C McLeod, James W Roy, Gregory F Slater, James E Smith
The use of ethanol in alternative fuels has led to contamination of groundwater with high concentrations of this easily biodegradable organic compound. Previous laboratory and field studies have shown vigorous biodegradation of ethanol plumes, with prevalence of reducing conditions and methanogenesis. The objective of this study was to further our understanding of the dynamic biogeochemistry processes, especially dissolved gas production, that may occur in developing and aging plume cores at sites with ethanol or other organic contamination of groundwater...
December 5, 2017: Journal of Contaminant Hydrology
Man Jae Kwon, Edward J O'Loughlin, Baknoon Ham, Yunho Hwang, Moojoon Shim, Soonjae Lee
Subsurface biogeochemistry and contaminant dynamics during the remediation of diesel-contamination by in-situ soil flushing were investigated at a site located in a coastal region. An in-situ sampler containing diesel-contaminated soils separated into two size fractions (<0.063- and <2-mm) was utilized in two monitoring wells: DH1 (located close to the injection and extraction wells for in-situ soil flushing) and DH2 (located beyond sheet piles placed to block the transport of leaked diesel). Total petroleum hydrocarbon (TPH) concentrations and biogeochemical properties were monitored both in soil and groundwater for six months...
December 5, 2017: Journal of Environmental Management
Cynthia Gilmour, Tyler Bell, Ally Soren, Georgia Riedel, Gerhardt Riedel, Dianne Kopec, Drew Bodaly, Upal Ghosh
The efficacy of thin layer in situ soil amendments was tested as a potential tool for methylmercury (MeHg) risk mitigation in Penobscot River, ME, salt marsh. Salt marshes are sites of high MeHg accumulation within the Penobscot, and key targets for remediation. The study was a fully-crossed small plot study, with four treatments (activated carbon (AC), biochar, FeCl2, and lime) and unamended controls at two sites. Plots were monitored for two years. Porewater MeHg concentrations were the main endpoint, with impacts on sediment biogeochemistry as a secondary study goal...
December 4, 2017: Science of the Total Environment
Kristin M Mikkelson, Brent M Brouillard, Chelsea M Bokman, Jonathan O Sharp
Forested ecosystems throughout the world are experiencing increases in the incidence and magnitude of insect-induced tree mortality with large ecologic ramifications. Interestingly, correlations between water quality and the extent of tree mortality in Colorado montane ecosystems suggest compensatory effects from adjacent live vegetation that mute responses in less severely impacted forests. To this end, we investigated whether the composition of the soil bacterial community and associated functionality beneath beetle-killed lodgepole pine was influenced by the extent of surrounding tree mortality...
December 5, 2017: MBio
Jiang-Tao Qiao, Xiao-Min Li, Fang-Bai Li
Although biochar has great potential for heavy metal removal from sediments or soils, its impact on arsenic biogeochemistry in contaminated paddy fields remains poorly characterized. In this study, anaerobic microcosms were established with arsenic-contaminated paddy soil to investigate arsenic transformation as well as the potentially active microbial community and their transcriptional activities in the presence of biochar. The results demonstrated that biochar can simultaneously stimulate microbial reduction of As(V) and Fe(III), releasing high levels of As(III) into the soil solution relative to the control...
November 21, 2017: Journal of Hazardous Materials
V J Coles, M R Stukel, M T Brooks, A Burd, B C Crump, M A Moran, J H Paul, B M Satinsky, P L Yager, B L Zielinski, R R Hood
Marine ecosystem models have advanced to incorporate metabolic pathways discovered with genomic sequencing, but direct comparisons between models and "omics" data are lacking. We developed a model that directly simulates metagenomes and metatranscriptomes for comparison with observations. Model microbes were randomly assigned genes for specialized functions, and communities of 68 species were simulated in the Atlantic Ocean. Unfit organisms were replaced, and the model self-organized to develop community genomes and transcriptomes...
December 1, 2017: Science
Xuefeng Li, Nathalie Roevros, Frank Dehairs, Lei Chou
Diatoms constitute a major group of phytoplankton, accounting for ~20% of the world's primary production. It has been shown that iron (Fe) can be the limiting factor for phytoplankton growth, in particular, in the HNLC (High Nutrient Low Chlorophyll) regions. Iron plays thus an essential role in governing the marine primary productivity and the efficiency of biological carbon pump. Oceanic systems are undergoing continuous modifications at varying rates and magnitudes as a result of changing climate. The objective of our research is to evaluate how changing environmental conditions (dust deposition, ocean warming and acidification) can affect marine Fe biogeochemistry and diatom growth...
2017: PloS One
Edwin T Gnanaprakasam, Jonathan R Lloyd, Christopher Boothman, Kazi Matin Ahmed, Imtiaz Choudhury, Benjamin C Bostick, Alexander van Geen, Brian J Mailloux
Long-term exposure to trace levels of arsenic (As) in shallow groundwater used for drinking and irrigation puts millions of people at risk of chronic disease. Although microbial processes are implicated in mobilizing arsenic from aquifer sediments into groundwater, the precise mechanism remains ambiguous. The goal of this work was to target, for the first time, a comprehensive suite of state-of-the-art molecular techniques in order to better constrain the relationship between indigenous microbial communities and the iron and arsenic mineral phases present in sediments at two well-characterized arsenic-impacted aquifers in Bangladesh...
November 28, 2017: MBio
Ji-Hoon Lee, Bong-Joo Lee
Agricultural demands continuously increased use of groundwater, causing drawdown of water table and need of artificial recharge using adjacent stream waters. River water intrusion into groundwater can alter the geochemical and microbiological characteristics in the aquifer and subsurface. In an effort to investigate the subsurface biogeochemical activities before operation of artificial recharge at the test site, established at the bank of Nakdong River, Changwon, South Korea, organic carbon transported from river water to groundwater was mimicked and the effect on the indigenous microbial communities was investigated with the microcosm incubations of the groundwater and subsurface sediments...
November 25, 2017: Microbial Ecology
S Kersey Sturdivant, Megumi S Shimizu
Organic matter (OM) production and degradation is important in coastal estuaries, and OM fate is strongly influenced by the coupled interactions of bioturbation and biogeochemistry. From April to September 2013 sediment cores and a benthic observing system, Wormcam, were used to investigate the in situ relationship of biogeochemistry and macrofauna bioturbation in Cape Lookout Bight North Carolina. Wormcam imagery provided a vivid depiction of macrofauna functioning in an environment not previously observed, and affirmed the importance of fine-scale temporal observations of the benthic environment in situ...
2017: PloS One
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"