[Review of] \u3cem\u3eStable Isotopes and Biosphere–Atmosphere Interactions: Processes and Biological Controls\u3c/em\u3e

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1x2\u3csup\u3e7\u3c/sup\u3e Cartoons about Science

A tongue-in-cheek look at the world of natural science.https://uknowledge.uky.edu/pss_book/1002/thumbnail.jp

The Soil is Alive!

Grab a handful of soil. . . . . What does it look like? What does it feel like? It may seem rather ordinary; but look closer. What are you holding in your hand? A mixture of minerals and air with some water and organic matter? Is that all? No. There\u27s so much more to soil than that. For a soil scientist in general and a soil microbiologist in particular the soil is a living thing, a mixture of living and dead organisms in an organic/mineral matrix. Not every organism is identical, or as abundant, or does the same things, or is active at the same time. Some you can see and some you can\u27t, although we have various tools we can use to prove even the microscopic ones exist. Soil is the most immensely complicated and diverse ecosystem on the planet. And as the quotations above suggest, its care and feeding are vital to agriculture and vital to life

Water Quality and Fecal Indicator Bacteria

How can you tell if water is fit to drink? Color and taste aren\u27t reliable guides for water safety. Clear water can be contaminated with chemicals or microorganisms the senses can\u27t detect. One of the principle qualities of potable (drinkable) water is its freedom from microbial contaminants. This article will describe some criteria and methods that are used to determine the microbial quality of water

[Review of] \u3cem\u3eStable Isotopes and Biosphere–Atmosphere Interactions: Processes and Biological Controls\u3c/em\u3e

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Soil Microbial Community Response to Hexavalent Chromium in Planted and Unplanted Soil

Theories suggest that rapid microbial growth rates lead to quicker development of metal resistance. We tested these theories by adding hexavalent chromium [Cr(VI)] to soil, sowing Indian mustard (Brassica juncea), and comparing rhizosphere and bulk soil microbial community responses. Four weeks after the initial Cr(VI) application we measured Cr concentration, microbial biomass by fumigation extraction and soil extract ATP, tolerance to Cr and growth rates with tritiated thymidine incorporation, and performed community substrate use analysis with BIOLOG GN plates. Exchangeable Cr(VI) levels were very low, and therefore we assumed the Cr(VI) impact was transient. Microbial biomass was reduced by Cr(VI) addition. Microbial tolerance to Cr(VI) tended to be higher in the Cr-treated rhizosphere soil relative to the non-treated systems, while microorganisms in the Cr-treated bulk soil were less sensitive to Cr(VI) than microorganisms in the non-treated bulk soil. Microbial diversity as measured by population evenness increased with Cr(VI) addition based on a Gini coefficient derived from BIOLOG substrate use patterns. Principal component analysis revealed separation between Cr(VI) treatments, and between rhizosphere and bulk soil treatments. We hypothesize that because of Cr(VI) addition there was indirect selection for fast-growing organisms, alleviation of competition among microbial communities, and increase in Cr tolerance in the rhizosphere due to the faster turnover rates in that environment

Soil Microbial Community Response to Hexavalent Chromium in Planted and Unplanted Soil

Theories suggest that rapid microbial growth rates lead to quicker development of metal resistance. We tested these theories by adding hexavalent chromium [Cr(VI)] to soil, sowing Indian mustard (Brassica juncea), and comparing rhizosphere and bulk soil microbial community responses. Four weeks after the initial Cr(VI) application we measured Cr concentration, microbial biomass by fumigation extraction and soil extract ATP, tolerance to Cr and growth rates with tritiated thymidine incorporation, and performed community substrate use analysis with BIOLOG GN plates. Exchangeable Cr(VI) levels were very low, and therefore we assumed the Cr(VI) impact was transient. Microbial biomass was reduced by Cr(VI) addition. Microbial tolerance to Cr(VI) tended to be higher in the Cr-treated rhizosphere soil relative to the non-treated systems, while microorganisms in the Cr-treated bulk soil were less sensitive to Cr(VI) than microorganisms in the non-treated bulk soil. Microbial diversity as measured by population evenness increased with Cr(VI) addition based on a Gini coefficient derived from BIOLOG substrate use patterns. Principal component analysis revealed separation between Cr(VI) treatments, and between rhizosphere and bulk soil treatments. We hypothesize that because of Cr(VI) addition there was indirect selection for fast-growing organisms, alleviation of competition among microbial communities, and increase in Cr tolerance in the rhizosphere due to the faster turnover rates in that environment

Managing Nitrous Oxide Emissions in Agricultural Fields

Agriculture is a major contributor to atmospheric nitrous oxide (N2O) (Smith et al., 2014; Tian et al., 2015). Unfortunately, nitrous oxide destroys stratospheric ozone (O3) which protects us from ultraviolet radiation (Cicerone, 1989) and it increases ground level O3, whichis an air pollutant threatening human health and food production. Nitrous oxide is also 298 times more potent than an equivalent amount of carbon dioxide (CO2) in terms of trapping and absorbing reflected solar radiation (Forster et al., 2007). Basic chemistry and physics assure us that increased levels of N2O in the atmosphere are not good

The Fecal Coliform/Fecal Streptococci Ratio (FC/FS) And Water Quality in the Bluegrass Region of Kentucky

In the mid 70\u27 s, someone noticed that the ratio of two indicator bacteria in fecal wastes - fecal coliforms (FC) and fecal streptococci (FS) - was characteristic of particular animal wastes. In human wastes, the fecal coliform/fecal streptococci ratio (FC/FS ratio) was greater than 4. In domesticated animals, like cattle, the ratio was between 0.1 and 4.0. In wild animals, the ratio was less than 0.1. Since that time, many attempts have been made to use the ratio to determine the source of fecal bacteria in contaminated ground water