Fungal Transformation of Tree Stumps into a Suitable Resource for Xylophagous Beetles via Changes in Elemental Ratios

Abstract. Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygen-to-carbon (O : C), hydrogen-to-carbon (H : C), and organic mass-to-organic carbon (OM : OC) ratios, and of carbon oxidation state (OS C) for a vastly expanded laboratory data set of multifunctional oxidized OA standards. For the expanded standard data set, the method introduced by Aiken et al. (2008), which uses experimentally measured ion intensities at all ions to determine elemental ratios (referred to here as "Aiken-Explicit"), reproduces known O : C and H : C ratio values within 20% (average absolute value of relative errors) and 12%, respectively. The more commonly used method, which uses empirically estimated H2O+ and CO+ ion intensities to avoid gas phase air interferences at these ions (referred to here as "Aiken-Ambient"), reproduces O : C and H : C of multifunctional oxidized species within 28 and 14% of known values. The values from the latter method are systematically biased low, however, with larger biases observed for alcohols and simple diacids. A detailed examination of the H2O+, CO+, and CO2+ fragments in the high-resolution mass spectra of the standard compounds indicates that the Aiken-Ambient method underestimates the CO+ and especially H2O+ produced from many oxidized species. Combined AMS–vacuum ultraviolet (VUV) ionization measurements indicate that these ions are produced by dehydration and decarboxylation on the AMS vaporizer (usually operated at 600 °C). Thermal decomposition is observed to be efficient at vaporizer temperatures down to 200 °C. These results are used together to develop an "Improved-Ambient" elemental analysis method for AMS spectra measured in air. The Improved-Ambient method uses specific ion fragments as markers to correct for molecular functionality-dependent systematic biases and reproduces known O : C (H : C) ratios of individual oxidized standards within 28% (13%) of the known molecular values. The error in Improved-Ambient O : C (H : C) values is smaller for theoretical standard mixtures of the oxidized organic standards, which are more representative of the complex mix of species present in ambient OA. For ambient OA, the Improved-Ambient method produces O : C (H : C) values that are 27% (11%) larger than previously published Aiken-Ambient values; a corresponding increase of 9% is observed for OM : OC values. These results imply that ambient OA has a higher relative oxygen content than previously estimated. The OS C values calculated for ambient OA by the two methods agree well, however (average relative difference of 0.06 OS C units). This indicates that OS C is a more robust metric of oxidation than O : C, likely since OS C is not affected by hydration or dehydration, either in the atmosphere or during analysis.

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Isotopes and elemental ratios in multi-parameter mixing models

Limnology and Oceanography Methods ◽

10.4319/lom.2014.12.694 ◽

2014 ◽

Vol 12 (10) ◽

pp. 694-702 ◽

Cited By ~ 2

Author(s):

Kathy M. Loftis ◽

Christof Meile

Keyword(s):

Mixing Models ◽

Elemental Ratios

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Linking the Wrangellia Flood Basalts to the Galápagos Hotspot

10.21203/rs.3.rs-253688/v1 ◽

2021 ◽

Author(s):

J. Gregory Shellnutt ◽

Jaroslav Dostal ◽

Tung-Yi Lee

Keyword(s):

Mantle Plume ◽

Elevated Temperatures ◽

Volcanic Rocks ◽

Thermal Conditions ◽

Internal Variability ◽

Eastern Pacific ◽

Unique Region ◽

Elemental Ratios ◽

Trace Elemental ◽

The Caribbean

Abstract The Triassic volcanic rocks of Wrangellia erupted at an equatorial to tropical latitude that was within 3000 km of western North America. The mafic and ultramafic volcanic rocks are compositionally and isotopically similar to those of oceanic plateaux that were generated from a Pacific mantle plume-type source. The thermal conditions, estimated from the primitive rocks, indicate that it was a high temperature regime (T P > 1550°C) consistent with elevated temperatures expected for a mantle plume. The only active hotspot currently located near the equator of the eastern Pacific Ocean that was active during the Mesozoic and produced ultramafic volcanic rocks is the Galápagos hotspot. The calculated mantle potential temperatures, trace elemental ratios, and Sr-Nd-Pb isotopes of the Wrangellia volcanic rocks are within the range of those from the Caribbean Plateau and Galápagos Islands, and collectively have similar internal variability as the Hawaii-Emperor island chain. The paleogeographic constraints, thermal estimates, and geochemistry suggests that it is possible that the Galápagos hotspot generated the volcanic rocks of Wrangellia and the Caribbean plateau or, more broadly, that the eastern Pacific (Panthalassa) Ocean was a unique region where anomalously high thermal conditions either periodically or continually existed from ~230 Ma to the present day.

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Arginase (agaA) as a Fungal Transformation Marker

Fungal Biology - Genetic Transformation Systems in Fungi, Volume 2 ◽

10.1007/978-3-319-10503-1_12 ◽

2014 ◽

pp. 155-160

Author(s):

Kashyap Dave ◽

Manmeet Ahuja ◽

T. N. Jayashri ◽

Rekha Bisht Sirola ◽

Khyati Dave ◽

...

Keyword(s):

Fungal Transformation

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Elemental Ratios in Foliage and Soil of a Jeffrey Pine Stand Subjected to Thinning and Burning Restoration Practices

Forest Research Open Access ◽

10.4172/2168-9776.1000180 ◽

2016 ◽

Vol 5 (3) ◽

Author(s):

Walker RF ◽

Fecko RM ◽

Johnson DW ◽

Miller WW

Keyword(s):

Elemental Ratios ◽

Jeffrey Pine ◽

Restoration Practices

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Bk and Cf chromatographic separation and 249Bk/248Cm and 249Cf/248Cm elemental ratios determination by inductively coupled plasma quadrupole mass spectrometry

Talanta ◽

10.1016/j.talanta.2012.11.056 ◽

2013 ◽

Vol 106 ◽

pp. 39-44 ◽

Cited By ~ 8

Author(s):

A. Gourgiotis ◽

H. Isnard ◽

A. Nonell ◽

M. Aubert ◽

G. Stadelmann ◽

...

Keyword(s):

Mass Spectrometry ◽

Chromatographic Separation ◽

Inductively Coupled Plasma ◽

Quadrupole Mass ◽

Elemental Ratios ◽

Quadrupole Mass Spectrometry ◽

Inductively Coupled

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High spatial resolution mapping of aerosol composition and sources in Oakland, California using mobile aerosol mass spectrometry

10.5194/acp-2018-703 ◽

2018 ◽

Cited By ~ 1

Author(s):

Rishabh U. Shah ◽

Ellis S. Robinson ◽

Peishi Gu ◽

Allen Robinson ◽

Joshua S. Apte ◽

...

Keyword(s):

Urban Areas ◽

Central Business District ◽

Photochemical Activity ◽

Spatial And Temporal Patterns ◽

Aerosol Composition ◽

Elemental Ratios ◽

Air Masses ◽

Aerosol Mass ◽

Secondary Origin ◽

Primary Emissions

Abstract. We investigated spatial and temporal patterns in concentration and composition of sub-micron particulate matter (PM1) in Oakland, California in the summer of 2017 using an aerosol mass spectrometer mounted in a mobile laboratory. We performed ∼ 160 hours of mobile sampling in the city over a 20-day period. Measurements are compared for three adjacent neighborhoods with distinct land uses: a central business district (downtown), a residential district (West Oakland), and a major shipping port. The average organic aerosol (OA) concentration is 5.3 μgm−3 and contributes ∼ 50 % of the PM1 mass. OA concentrations in downtown are, on average, 1.5 μgm−3 higher than in West Oakland and Port. We decomposed OA into three factors using positive matrix factorization: hydrocarbon-like OA (HOA; 20 % average contribution), cooking OA (COA; 25 %) and semi-volatile oxidized OA (SV-OOA; 55 %). The collective 45 % contribution from primary OA (HOA + COA) emphasizes the importance of primary emissions in Oakland. The dominant source of primary OA shifts from HOA-rich in the morning to COA-rich after lunch time. COA in downtown is consistently higher than West Oakland and Port due to a large number of restaurants. HOA exhibits variability in space and time. Morning-time HOA concentration in downtown is twice that in Port, but Port HOA increases more than two-fold during mid-day, likely because trucking activity at the Port peaks at that time. Despite the expectation of being spatially uniform, SV-OOA also exhibits spatial differences. Morning-time SV-OOA in downtown is roughly 25 % (∼ 0.6 μgm−3) higher than the rest of Oakland. Even as the entire domain approaches a more uniform photo-chemical state in the afternoon, downtown SV-OOA remains statistically higher than West Oakland and Port, suggesting that downtown is a microenvironment with higher photochemical activity. Higher concentrations of particulate sulfate (also of secondary origin) with no direct sources in Oakland further reflect higher photochemical activity in downtown. A combination of several factors (poor ventilation of air masses in street canyons, higher concentrations of precursor gases, higher concentrations of the hydroxyl radical) likely result in the proposed high photochemical activity in downtown. Lastly, through Van Krevelen analysis of elemental ratios (H/C, O/C) of the OA, we show that OA in Oakland is more chemically reduced than several other urban areas. This underscores the importance of primary emissions in Oakland. We also show that mixing of oceanic air masses with these primary emissions in Oakland is an important processing mechanism that governs the overall OA composition in Oakland. The findings of this study are important because the pollutants we find contributing the most to OA variability, both of primary and secondary origin, are ubiquitous in other urban locations.

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A model for variable phytoplankton stoichiometry based on cell protein regulation

Biogeosciences Discussions ◽

10.5194/bgd-10-3241-2013 ◽

2013 ◽

Vol 10 (2) ◽

pp. 3241-3279

Author(s):

J. A. Bonachela ◽

S. D. Allison ◽

A. C. Martiny ◽

S. A. Levin

Keyword(s):

Physiological State ◽

Single Point ◽

Nutrient Content ◽

Growth Conditions ◽

Marine Phytoplankton ◽

Cell Protein ◽

Nitrogen And Phosphorus ◽

Elemental Ratios ◽

Regulatory Processes ◽

Complex Interactions

Abstract. The elemental ratios of marine phytoplankton emerge from complex interactions between the biotic and abiotic components of the ocean, and reflect the plastic response of individuals to changes in their environment. The stoichiometry of phytoplankton is, thus, dynamic and dependent on the physiological state of the cell. We present a theoretical model for the dynamics of the carbon, nitrogen and phosphorus contents of a phytoplankton population. By representing the regulatory processes controlling nutrient uptake, and focusing on the relation between nutrient content and protein synthesis, our model qualitatively replicates existing experimental observations for nutrient content and ratios. The population described by our model takes up nutrients in proportions that match the input ratios for a broad range of growth conditions. In addition, there are two zones of single-nutrient limitation separated by a wide zone of co-limitation. Within the co-limitation zone, a single point can be identified where nutrients are supplied in an optimal ratio. The existence of a wide co-limitation zone affects the standard picture for species competing for nitrogen and phosphorus, which shows here a much richer pattern. However, additional comprehensive laboratory experiments are needed to test our predictions. Our model contributes to the understanding of the global cycles of oceanic nitrogen and phosphorus, as well as the elemental ratios of these nutrients in phytoplankton populations.

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