scholarly journals Optimization of viral resuspension methods for carbon-rich soils along a permafrost thaw gradient

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1999 ◽  
Author(s):  
Gareth Trubl ◽  
Natalie Solonenko ◽  
Lauren Chittick ◽  
Sergei A. Solonenko ◽  
Virginia I. Rich ◽  
...  
Keyword(s):  
Organic Matter ◽  
Storage Conditions ◽  
Potassium Citrate ◽  
Soil Types ◽  
Citrate Buffer ◽  
Permafrost Thaw ◽  
C Cycling ◽  
Permafrost Soils ◽  
Order Of Magnitude ◽  
The Impact

Permafrost stores approximately 50% of global soil carbon (C) in a frozen form; it is thawing rapidly under climate change, and little is known about viral communities in these soils or their roles in C cycling. In permafrost soils, microorganisms contribute significantly to C cycling, and characterizing them has recently been shown to improve prediction of ecosystem function. In other ecosystems, viruses have broad ecosystem and community impacts ranging from host cell mortality and organic matter cycling to horizontal gene transfer and reprogramming of core microbial metabolisms. Here we developed an optimized protocol to extract viruses from three types of high organic-matter peatland soils across a permafrost thaw gradient (palsa, moss-dominated bog, and sedge-dominated fen). Three separate experiments were used to evaluate the impact of chemical buffers, physical dispersion, storage conditions, and concentration and purification methods on viral yields. The most successful protocol, amended potassium citrate buffer with bead-beating or vortexing and BSA, yielded on average as much as 2-fold more virus-like particles (VLPs) g−1of soil than other methods tested. All method combinations yielded VLPs g−1of soil on the 108order of magnitude across all three soil types. The different storage and concentration methods did not yield significantly more VLPs g−1of soil among the soil types. This research provides much-needed guidelines for resuspending viruses from soils, specifically carbon-rich soils, paving the way for incorporating viruses into soil ecology studies.

scholarly journals Absence of Saharan dust influence on the strontium isotope ratios on modern trees from the Bahamas and Turks and Caicos Islands

2018 ◽  
Vol 89 (2) ◽  
pp. 394-412 ◽  
Author(s):  
Rick Schulting ◽  
Mike Richards ◽  
John Pouncett ◽  
Bryan Naqqi Manco ◽  
Ethan Freid ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Saharan Dust ◽  
Soil Types ◽  
Sr Isotope ◽  
The Bahamas ◽  
Turks And Caicos Islands ◽  
Order Of Magnitude ◽  
The Caribbean ◽  
The Impact ◽  
Bahamian Archipelago

AbstractWe report on strontium (87Sr/86Sr) isotope results from 91 modern trees growing on the Bahamas and Turks and Caicos Islands. The average87Sr/86Sr ratio of 0.709169±0.000010 is consistent with the late Quaternary limestone of the islands and with the modern ocean value. The absence of any detectable influence of87Sr-enriched Saharan dust is notable, given the known contribution of this material to both past and recent soils of the Caribbean. Our results indicate that the impact of Saharan dust to the modern biosphere of the Bahamian archipelago is at least an order of magnitude less than modeled in currently available strontium isoscapes for the circum-Caribbean. We suggest that the bioavailability of Sr in Saharan dust may be considerably less than previously thought. Nevertheless, further work could usefully be carried out in the Bahamian archipelago on plants with different rooting depths, growing on different soil types and on limestone of different ages. Our results have particular relevance for the refinement of existing strontium isoscapes and the archaeological provenience of artifacts, animals, and people in the circum-Caribbean.

Millennia-old carbon fluxes from degraded tropical peatland soils

2020 ◽  
Author(s):  
Stephanie Evers ◽  
Thomas Smith ◽  
Mark Garnett ◽  
Selvakumar Dhandipani ◽  
Massimo Lupascu
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Land Use Change ◽  
Ecosystem Respiration ◽  
Critical Element ◽  
Tropical Peatland ◽  
Agricultural Conversion ◽  
C Cycling ◽  
The Impact ◽  
Global Carbon

<p>Assessing the flux of carbon (C) from terrestrial ecosystems to the atmosphere represents a critical element of global carbon budgeting. In tropical peatlands this has been a fundamental part of assessing the impact of land use change on an ecosystem that represents a significant global carbon store, with peat accumulation being often many meters deep. These systems have formed over thousands of years as a function of incomplete decomposition of organic matter from water-logged swamp forests. However, intact tropical peat swamp forests (PSFs) are under increasing threat from agricultural conversion, deforestation, drainage practices and fires. The resultant alteration of the peat soil results in peat oxidation, increased rates of organic matter decomposition and greenhouse gas (GHG) emissions. Consequently, these peats are reverting from C stores to sources.</p><p>Radiocarbon (<sup>14</sup>C) abundance can be used to assess C cycling rates in varied ecosystems and identify rapid or slow C turnover rates from years to centuries, as well as shifts in cycling rates – for example with land use or hydrological alteration. Within intact peatlands, deep peats generally contain an increasing abundance of <sup>14</sup>C depleted content due to radioactive decay, conversely, shallower peats are more abundant in recently produced organic litter enriched with “Bomb C”; derived from nuclear testing in the 1960s. Similarly, root derived organic matter and the associated root respiration (autotrophic respiration) also have signatures resembling recent atmospheres, whereas microbial respiration of soil organic matter (heterotrophic respiration) will resemble the mean age of the soil carbon being utilised by the microbial community, and as such can be a tracer for sources of carbon being decomposed. </p><p>Yet while an increasing body of knowledge exists on tropical peatland carbon flux rates or net ecosystem respiration in association with land-use change, these approaches fail to delineate the sources of carbon being used within the soil profile and thus fully address questions linked to changing carbon cycling rates with land use change.</p><p>Here we provide what we believe to be the first data on <sup>14</sup>CO<sub>2</sub> fluxes from tropical peatland soils in relation to varying land use classes with the aim of determining if peats which were previously long-terms C stores are being utilised within short, fast C cycles and thus contributing to modern GHG budgets. CO<sub>2</sub> flux rates were measured using soil chambers and emitted CO<sub>2</sub> was subsequently trapped on a zeolite molecular sieve cartridge. An aliquot of the recovered CO<sub>2</sub> was graphitised and analysed for <sup>14</sup>C by accelerator mass spectrometry. Associated soil age profiles were also determined.</p><p>Results indicate significant fluxes of multi-millennia old carbon from peatlands under altered land use classes and clear evidence for a shift to C cycling speed, with previously long-term stored C contributing to modern C budgets. Result highlight the instability of the peat profile under altered land-use classes and minimal to no contribution of modern C from recently produced organic matter to these carbon budgets. Findings clearly indicate the unsustainability of these agricultural practices and the need for burn- and drain-free land-use strategies.</p>

scholarly journals Small variations of soil properties control fire-induced water repellency .

2014 ◽  
Vol 4 ◽  
Author(s):  
Jorge Mataix-Solera ◽  
Lorena M. Zavala ◽  
Antonio Jordán ◽  
Gema Bárcenas-Moreno ◽  
Elena Lozano ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Properties ◽  
Plant Species ◽  
Water Repellency ◽  
Soil Samples ◽  
Soil Types ◽  
Water Repellent ◽  
Key Factors ◽  
The Impact

Fire induced soil water repellency (WR) is controlled by many different factors (temperature reached, amount and type of fuel, etc.). Soil properties may determine the occurrence and intensity of this property in burned soils. The objectives of this paper are to make advances in the study of soil properties as key factors controlling the behaviour of fire-induced WR, and to study the impact of pre-fire SOM content and SOM quality in fire-induced soil WR. In this research, experimental laboratory burnings were carried out using soil samples from different sites with different lithologies, soil types and plant species. Soil samples taken from the same site differ only in quantity and quality of soil organic matter, as they were collected from under different plant species. All soil samples were heated in a muffle furnace at 200, 250, 300 and 350 ºC without the addition of any fuel load. WR was measured using the water drop penetration time test (WDPT). The results showed significant differences between soil types and plant species, indicating that small differences in soil properties may act as key factors controlling the development and persistence of WR reached, with burned soil samples ranging from wettable to extremely water repellent. The main soil property controlling the response was texture, specifically sand content. The quality of organic matter was also observed to have an effect, since soil samples from the same site with similar organic matter contents, but taken from beneath different plant species, showed different WR values after burning.

scholarly journals Mobilization of particulate organic matter and minerals in Zackenberg valley, Greenland

2021 ◽  
Author(s):  
Lisa Bröder ◽  
Catherine Hirst ◽  
Sophie Opfergelt ◽  
Julie Lattaud ◽  
Negar Haghipour ◽  
...  
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Soil Samples ◽  
Headwater Stream ◽  
Decay Kinetics ◽  
X Ray ◽  
Additional Information ◽  
Permafrost Thaw ◽  
Permafrost Soils ◽  
Retrogressive Thaw Slump

<p>Ongoing warming of the Northern high latitudes has intensified abrupt thaw processes throughout the permafrost zone. The resulting terrain disturbances are prone to release large amounts of particulate organic matter (OM) from deeper permafrost soils with thus far poorly constrained decay kinetics. Organo-mineral interactions may inhibit OM decomposition, thereby mediating the release of carbon to the atmosphere. Yet how these interactions evolve upon release and during transport along the fluvial continuum is still insufficiently understood. Here we investigate the mobilization of particulate OM from disturbed permafrost soils to the aquatic environment in the Zackenberg watershed in Northeastern Greenland. We collected soil samples in a thermo-erosion gully and a retrogressive thaw slump, as well as suspended solids and stream sediments along the glacio-nival Zackenberg River, including its tributaries, and a small headwater stream (Grænselv) affected by abrupt permafrost thaw. To evaluate the organic and mineral material transported, we compare mineral element and organic carbon (OC) concentrations, bulk carbon isotopes (<sup>13</sup>C and <sup>14</sup>C), together with source-specific molecular biomarkers (plant-wax lipids and branched glycerol dialkyl glycerol tetraethers, brGDGTs) for the suspended load with their soil and sediment counterparts.</p><p>Preliminary results show large contrasts in OC concentrations as well as Δ<sup>14</sup>C between the glacio-nival river and the headwater stream, as well as between the different thaw features. The retrogressive thaw slump mobilizes relatively OC-poor material with very low Δ<sup>14</sup>C signatures suggesting a petrogenic contribution, while soil samples from the thermo-erosion gully had higher OC concentrations and Δ<sup>14</sup>C values. For Grænselv, Δ<sup>14</sup>C values of the particulate OC were lower close to the eroding stream bank, whereas the Zackenberg main stem displayed fairly constant Δ<sup>14</sup>C values, with some of the Zackenberg tributaries delivering relatively organic-rich particles low in Δ<sup>14</sup>C.</p><p>Molecular biomarker analyses will provide additional information on specific OM sources, while X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) analyses on the soils, sediments and suspended mineral load will give more detailed insights into the composition of the mineral matrices. By combining these analytical methods, we aim to improve our understanding of the interactions between minerals and OM and thereby help to constrain the fate of mobilized OM upon permafrost thaw.</p>

The impact of urban effluents on the coastal marine environment of Mediterranean islands

1995 ◽  
Vol 32 (9-10) ◽  
pp. 85-94 ◽  
Author(s):  
Michael O. Angelidis
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Marine Environment ◽  
Suspended Particle ◽  
Pollution Source ◽  
Mediterranean Islands ◽  
Coastal Marine Environment ◽  
Coastal Marine ◽  
The Impact ◽  
The City

The impact of the urban effluents of Mytilene (Lesvos island, Greece) on the receiving coastal marine environment, was evaluated by studying the quality of the city effluents (BOD5, COD, SS, heavy metals) and the marine sediments (grain size, organic matter, heavy metals). It was found that the urban effluents of Mytilene contain high organic matter and suspended particle load because of septage discharge into the sewerage network. Furthermore, although the city does not host important industrial activity, its effluents contain appreciable metal load, which is mainly associated with the particulate phase. The city effluents are discharged into the coastal marine environment and their colloidal and particulate matter after flocculation settles to the bottom, where is incorporated into the sediments. Over the years, the accumulation of organic matter and metals into the harbour mud has created a non-point pollution source in the relatively non-polluted coastal marine environment of the island. Copper and Zn were the metals which presented the higher enrichment in the sediments of the inner harbour of Mytilene.

Fish farming in Denmark: environmental impact of regulative legislation

1995 ◽  
Vol 31 (10) ◽  
pp. 73-84 ◽  
Author(s):  
T. M. Iversen
Keyword(s):  
Organic Matter ◽  
Environmental Impact ◽  
Freshwater Fish ◽  
Aquatic Environment ◽  
Action Plan ◽  
Fish Farming ◽  
Fish Farms ◽  
Nitrogen And Phosphorus ◽  
Local Impact ◽  
The Impact

The main environmental problems associated with fish farming in Denmark are attributable to the dam, the “dead reach” and nutrient and organic matter discharge. The environmental regulation of fish farming in Denmark started with the Environmental Protection Act of 1974, the Statutory Order of 1985 forbidding wet feed, and the Action Plan on the Aquatic Environment of 1987. In the case of freshwater fish farms, the latter was implemented through the measures stipulated in the 1989 Statutory Order on Fish Farms. The impact of Danish legislative measures to reduce and regulate the environmental effects of freshwater fish farms can be summarized as follows: - the number of fish farms has been reduced from about 800 in 1974 to about 500 at present; - production has tripled since 1974 and has been stable since 1989; - a change from wet to dry feed has reduced the environmental impact of the farms; - the national goals of the Action Plan on the Aquatic Environment of 1987 for reducing fish farm discharges of organic matter, nitrogen and phosphorus have been fulfilled. The main remaining problems are that: - the local impact of fish farms on downstream stream quality is still much too high in about 15% of cases; - the problem of the passage of migrating invertebrates and fish is still unsolved at some farms; - the problems posed by “dead reaches” are still unsolved. It is concluded that sustainable fish farming is possible in Denmark, but with the present technology production will have to be significantly reduced.

Pound Wise and Penny Foolish? Weight Loss and The Dynamics of Health Care Spending

2011 ◽  
Vol 14 (2) ◽  
Author(s):  
Thomas G Koch
Keyword(s):  
Weight Loss ◽  
Cost Savings ◽  
Cost Effective ◽  
Economic Consequences ◽  
Health Care Spending ◽  
Order Of Magnitude ◽  
Dynamic Measures ◽  
The Cost ◽  
The Impact ◽  
The Relationship

Current estimates of obesity costs ignore the impact of future weight loss and gain, and may either over or underestimate economic consequences of weight loss. In light of this, I construct static and dynamic measures of medical costs associated with body mass index (BMI), to be balanced against the cost of one-time interventions. This study finds that ignoring the implications of weight loss and gain over time overstates the medical-cost savings of such interventions by an order of magnitude. When the relationship between spending and age is allowed to vary, weight-loss attempts appear to be cost-effective starting and ending with middle age. Some interventions recently proven to decrease weight may also be cost-effective.

scholarly journals Effect of Storage Conditions on Storability and Antioxidant Potential of Pears cv. ‘Conference’

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 545
Author(s):  
Grzegorz P. Łysiak ◽  
Krzysztof Rutkowski ◽  
Dorota Walkowiak-Tomczak
Keyword(s):  
Mass Loss ◽  
Strong Influence ◽  
Storage Conditions ◽  
Quality Parameters ◽  
Soluble Solids ◽  
Controlled Atmosphere ◽  
Postharvest Diseases ◽  
Market Prices ◽  
Long Period ◽  
The Impact

Late pear cultivars, such as ‘Conference’, can be stored for a long period if kept in good storage conditions. A three-year study (2011–2013) compared the impact of six-month storage using four technologies—normal atmosphere, normal atmosphere + 1-methylcyclopropene (1-MCP), controlled atmosphere, and controlled atmosphere + 1-MCP—on the quality parameters of ‘Conference’ pears, such as mass loss, firmness, total soluble solids, acidity, antioxidant capacity, and the incidence of diseases and disorders. Additionally, the study analysed different storage conditions in terms of profitability, based on the market prices for pears in the seasons during which the pears were stored. The storage conditions had a very strong influence on the fruit quality parameters, and were found to affect most visibly the mass loss and the incidence of postharvest diseases and disorders. The storage of ‘Conference’ pears for 180 days in normal atmosphere is not economically viable, even if the fruit is subjected to 1-MCP treatment; at the same time, it is profitable to store ‘Conference’ pears in controlled atmosphere for the same period, no matter whether 1-MCP was applied or not.

scholarly journals Ice Coverage Induced by Depositing a Water Drop onto the Supercooled Substrate at Extreme Low Vapor Pressure

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 691
Author(s):  
Yugang Zhao ◽  
Zichao Zuo ◽  
Haibo Tang ◽  
Xin Zhang
Keyword(s):  
Vapor Pressure ◽  
Substrate Temperature ◽  
Water Drop ◽  
Industrial Processes ◽  
Aircraft Icing ◽  
Ice Coverage ◽  
Fundamental Understanding ◽  
Order Of Magnitude ◽  
The Impact ◽  
Kinetics Of

Icing/snowing/frosting is ubiquitous in nature and industrial processes, and the accretion of ice mostly leads to catastrophic consequences. The existing understanding of icing is still limited, particularly for aircraft icing, where direct observation of the freezing dynamics is inaccessible. In this work, we investigate experimentally the impact and freezing of a water drop onto the supercooled substrate at extremely low vapor pressure, to mimic an aircraft passing through clouds at a relatively high altitude, engendering icing upon collisions with pendant drops. Special attention is focused on the ice coverage induced by an impinging drop, from the perimeter pointing outward along the radial direction. We observed two freezing regimes: (I) spread-recoil-freeze at the substrate temperature of Ts = −15.4 ± 0.2 °C and (II) spread (incomplete)-freeze at the substrate temperature of Ts = −22.1 ± 0.2 °C. The ice coverage is approximately one order of magnitude larger than the frozen drop itself, and counterintuitively, larger supercooling yields smaller ice coverage in the range of interest. We attribute the variation of ice coverage to the kinetics of vapor diffusion in the two regimes. This fundamental understanding benefits the design of new anti-icing technologies for aircraft.

scholarly journals Microbial Growth Study on Pork Loins as Influenced by the Application of Different Antimicrobials

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 968
Author(s):  
David A. Vargas ◽  
Markus F. Miller ◽  
Dale R. Woerner ◽  
Alejandro Echeverry
Keyword(s):  
Storage Time ◽  
Microbial Growth ◽  
Storage Conditions ◽  
Indicator Bacteria ◽  
Aerobic Bacteria ◽  
Growth Study ◽  
Treatment Interventions ◽  
Pork Industry ◽  
Bacterial Enumeration ◽  
The Impact

The use of antimicrobials in the pork industry is critical in order to ensure food safety and, at the same time, extend shelf life. The objective of the study was to determine the impact of antimicrobials on indicator bacteria on pork loins under long, dark, refrigerated storage conditions. Fresh boneless pork loins (n = 36) were split in five sections and treated with antimicrobials: Water (WAT), Bovibrom 225 ppm (BB225), Bovibrom 500 ppm (BB500), Fit Fresh 3 ppm (FF3), or Washing Solution 750 ppm (WS750). Sections were stored for 1, 14, 28, and 42 days at 2–4 °C. Mesophilic and psychrotrophic aerobic bacteria (APC-M, APC-P), lactic acid bacteria (LAB-M), coliforms, and Escherichia coli were enumerated before intervention, after intervention, and at each storage time. All bacterial enumeration data were converted into log10 for statistical analysis, and the Kruskal–Wallis test was used to find statistical differences (p < 0.05). Initial counts did not differ between treatments, while, after treatment interventions, treatment WS750 did not effectively reduce counts for APC-M, APC-P, and coliforms (p < 0.01). BB500, FF3, and WS750 performed better at inhibiting the growth of indicator bacteria when compared with water until 14 days of dark storage.

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