Seasonal Dynamics of Dissolved Methane in Lakes of the Mackenzie Delta and the Role of Carbon Substrate Quality

2018 ◽  
Vol 123 (2) ◽  
pp. 591-609 ◽  
Author(s):  
C. L. Cunada ◽  
L. F. W. Lesack ◽  
S. E. Tank
Keyword(s):  
Seasonal Dynamics ◽  
Carbon Substrate ◽  
Mackenzie Delta ◽  
Dissolved Methane ◽  
Substrate Quality

scholarly journals The Species Composition and Seasonal Dynamics of Thrips (Thysanoptera) Populations on Maize (Zea Mays L.) in Southeastern Poland

2011 ◽  
Vol 51 (3) ◽  
pp. 210-216 ◽  
Author(s):  
Halina Kucharczyk ◽  
Paweł Bereś ◽  
Zbigniew Dąbrowski
Keyword(s):  
Zea Mays ◽  
Species Composition ◽  
Seasonal Dynamics ◽  
Food Source ◽  
Zea Mays L ◽  
Maize Plant ◽  
Seasonal Abundance ◽  
Immature Stages ◽  
Thrips Species

The Species Composition and Seasonal Dynamics of Thrips (Thysanoptera) Populations on Maize (Zea MaysL.) in Southeastern PolandThrips species composition and seasonal abundance was studied on maize crops during two seasons (2006-2007), in southeastern Poland. Altogether 21 species have been identified, among themFrankliniella tenuicornis(Uzel 1895) andHaplothrips aculeatus(Fabricius 1803) which are a graminicolous species and were eudominants, comprising 96.8% in 2006 and 82.0% in 2007 of all collected specimens. Other species occurred only in low numbers. The frequent and numerous presence ofF. tenuicornisspecies in their immature stages in the samples, confirmed the role of the maize plant as the host.H. aculeatusprobably chose maize as a food source and substitute plant for breeding.

Nickel–Nitrogen–Carbon Molecular Catalysts for High Rate CO2 Electro-reduction to CO: On the Role of Carbon Substrate and Reaction Chemistry

2020 ◽  
Vol 3 (2) ◽  
pp. 1617-1626 ◽  
Author(s):  
Tianyu Zhang ◽  
Lili Lin ◽  
Zhengyuan Li ◽  
Xingyu He ◽  
Shengdong Xiao ◽  
...  
Keyword(s):  
High Rate ◽  
Carbon Substrate ◽  
Molecular Catalysts

Physical limitations of dissolved methane fluxes: The role of bottom-boundary layer processes

2010 ◽  
Vol 272 (1-4) ◽  
pp. 209-222 ◽  
Author(s):  
Peter Linke ◽  
Stefan Sommer ◽  
Lorenzo Rovelli ◽  
Daniel F. McGinnis
Keyword(s):  
Boundary Layer ◽  
Bottom Boundary Layer ◽  
Dissolved Methane ◽  
Bottom Boundary ◽  
Boundary Layer Processes ◽  
Methane Fluxes ◽  
Physical Limitations

scholarly journals Contribution of fine tree roots to the silicon cycle in a temperate forest ecosystem developed on three soil types

2018 ◽  
Vol 15 (7) ◽  
pp. 2231-2249 ◽  
Author(s):  
Marie-Pierre Turpault ◽  
Christophe Calvaruso ◽  
Gil Kirchen ◽  
Paul-Olivier Redon ◽  
Carine Cochet
Keyword(s):  
Seasonal Dynamics ◽  
Forest Floor ◽  
Fine Roots ◽  
Temperate Forest ◽  
Forest Ecosystems ◽  
Soil Layer ◽  
Soil Types ◽  
Root Decomposition ◽  
Soil Layers

Abstract. The role of forest vegetation in the silicon (Si) cycle has been widely examined. However, to date, little is known about the specific role of fine roots. The main objective of our study was to assess the influence of fine roots on the Si cycle in a temperate forest in north-eastern France. Silicon pools and fluxes in vegetal solid and solution phases were quantified within each ecosystem compartment, i.e. in the atmosphere, above-ground and below-ground tree tissues, forest floor and different soil layers, on three plots, each with different soil types, i.e. Dystric Cambisol (DC), Eutric Cambisol (EC) and Rendzic Leptosol (RL). In this study, we took advantage of a natural soil gradient, from shallow calcic soil to deep moderately acidic soil, with similar climates, atmospheric depositions, species compositions and management. Soil solutions were measured monthly for 4 years to study the seasonal dynamics of Si fluxes. A budget of dissolved Si (DSi) was also determined for the forest floor and soil layers. Our study highlighted the major role of fine roots in the Si cycle in forest ecosystems for all soil types. Due to the abundance of fine roots mainly in the superficial soil layers, their high Si concentration (equivalent to that of leaves and 2 orders higher than that of coarse roots) and their rapid turnover rate (approximately 1 year), the mean annual Si fluxes in fine roots in the three plots were 68 and 110 kgha-1yr-1 for the RL and the DC, respectively. The turnover rates of fine roots and leaves were approximately 71 and 28 % of the total Si taken up by trees each year, demonstrating the importance of biological recycling in the Si cycle in forests. Less than 1 % of the Si taken up by trees each year accumulated in the perennial tissues. This study also demonstrated the influence of soil type on the concentration of Si in the annual tissues and therefore on the Si fluxes in forests. The concentrations of Si in leaves and fine roots were approximately 1.5–2.0 times higher in the Si-rich DC compared to the Si-poor RL. In terms of the DSi budget, DSi production was large in the three plots in the forest floor (9.9 to 12.7 kgha-1yr-1), as well as in the superficial soil layer (5.3 to 14.5 kgha-1yr-1), and decreased with soil depth. An immobilization of DSi was even observed at 90 cm depth in plot DC (−1.7 kgha-1yr-1). The amount of Si leached from the soil profile was relatively low compared to the annual uptake by trees (13 % in plot DC to 29 % in plot RL). The monthly measurements demonstrated that the seasonal dynamics of the DSi budget were mainly linked to biological activity. Notably, the peak of dissolved Si production in the superficial soil layer occurred during winter and probably resulted from fine-root decomposition. Our study reveals that biological processes, particularly those involving fine roots, play a predominant role in the Si cycle in temperate forest ecosystems, while the geochemical processes appear to be limited.

Genesis of Solonetzic soils as a function of topography and seasonal dynamics

1994 ◽  
Vol 74 (2) ◽  
pp. 207-217 ◽  
Author(s):  
J. J. Miller ◽  
S. Pawluk
Keyword(s):  
Seasonal Dynamics ◽  
Slope Position ◽  
Seasonal Fluctuations ◽  
Topographic Position ◽  
Exchangeable Acidity ◽  
Sodium Percent ◽  
Acidic Conditions ◽  
Lower Slope ◽  
Upper Slope

A Gleyed Black Solonetz at a depressional slope position, a Black Solonetz at a lower slope position, a Black Solodized Solonetz at a mid-slope position, and a Black Solod at an upper slope position in central Alberta, were investigated using chemical, physical and mineralogical techniques to determine the role of topographic position and season in their genesis. Solonization, as indicated by electrical conductivity (EC) values < 4 dS m−1 and exchangeable sodium percent (ESP) values > 15% in the B horizon, was greatest in the Gleyed Black Solonetz, and then decreased in the soils upslope. Solonization occurred during the spring, summer and fall in the B horizon of the Gleyed Black Solonetz and Bnt1 horizon of the Black Solod, and during the spring in the B horizon of the Black Solonetz, Bnt1 horizon of the Black Solodized Solonetz, and Bnt2 horizon of the Black Solod. Solodization, as indicated by the development of Ae and AB horizons, acidic conditions and higher dithionite-extractable Al in the upper sola, and high exchangeable acidity in the upper B horizons, was greatest in the Black Solod at the upper slope position, moderate in the Black Solodized Solonetz at the mid-slope position, and absent in the two soils at the lower slope positions. Solodization as reflected by exchangeable acidity, also exhibited seasonal fluctuations, particularly in the upper B horizons. Seasonal variations of exchangeable Na, Ca and Mg in the B horizons, however, were slight to nonexistent. Topographic position and seasonal fluctuations of soluble salts and exchangeable acidity in the B horizons played a major role in the genesis of soils in this Solonetzic catena. Key words: Solonetzic catena, solonization, solodization, topography, seasonal dynamics

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