scholarly journals Spatial changes in soil stable isotopic composition in response to carrion decomposition

2019 ◽  
Vol 16 (19) ◽  
pp. 3929-3939 ◽  
Author(s):  
Sarah W. Keenan ◽  
Sean M. Schaeffer ◽  
Jennifer M. DeBruyn
Keyword(s):  
Soft Tissue ◽  
Isotopic Composition ◽  
Microbial Communities ◽  
Soft Tissues ◽  
Soil Microbial Communities ◽  
Bulk Soil ◽  
Soil Biogeochemistry ◽  
Stable Isotopic Composition ◽  
Stable Isotopic ◽  
Carrion Decomposition

Abstract. Decomposition provides a critical mechanism for returning nutrients to the surrounding environment. In terrestrial systems, animal carcass, or carrion, decomposition results in a cascade of biogeochemical changes. Soil microbial communities are stimulated, resulting in transformations of carbon (C) and nitrogen (N) sourced from the decaying carrion soft tissues, changes to soil pH, electrical conductivity, and oxygen availability as microbial communities release CO2 and mineralize organic N. While many of the rapid changes to soil biogeochemistry observed during carrion decomposition return to background or starting conditions shortly after soft tissues are degraded, some biogeochemical parameters, particularly bulk soil stable δ15N isotopic composition, have the potential to exhibit prolonged perturbations, extending for several years. The goal of this study was to evaluate the lateral and vertical changes to soil stable isotopic composition 1 year after carrion decomposition in a forest ecosystem. Lateral transects extending 140 cm from three decomposition “hotspots” were sampled at 20 cm intervals, and subsurface cores were collected beneath each hotspot to a depth of 50 cm. Bulk soil stable isotopic composition (δ15N and δ13C) indicated that 1 year after complete soft tissue removal and decay, soils were significantly 15N enriched by 7.5±1.0 ‰ compared to control soils up to 60 cm from the hotspot center, and enrichment extended to a depth of 10 cm. Hotspot soils also contained 10 % more N compared to control soils, indicating that decomposition perturbs N pools. Our results demonstrate that carrion decomposition has the potential to result in long-term changes to soil biogeochemistry, up to at least 1 year after soft tissue degradation, and to contribute to bulk soil stable isotopic composition.

scholarly journals Spatial changes in soil stable isotopic composition in response to carrion decomposition

2019 ◽  
Author(s):  
Sarah W. Keenan ◽  
Sean M. Schaeffer ◽  
Jennifer M. DeBruyn
Keyword(s):  
Soft Tissue ◽  
Isotopic Composition ◽  
Microbial Communities ◽  
Soft Tissues ◽  
Bulk Soil ◽  
Soil Biogeochemistry ◽  
Stable Isotopic Composition ◽  
Stable Isotopic ◽  
One Year ◽  
Carrion Decomposition

Abstract. Decomposition provides a critical mechanism for returning nutrients to the surrounding environment. In terrestrial systems, animal carcass, or carrion, decomposition results in a cascade of biogeochemical changes. Soil microbial communities are stimulated, resulting in transformations of carbon (C) and nitrogen (N) sourced from the decaying carrion soft tissues, changes to soil pH and electrical conductivity as microbial communities release CO2 and mineralize organic N, and significant changes to oxygen availability. Over time, microbial communities transform ammonium to nitrate and potentially N2O through nitrification and denitrification. While many of the rapid changes to soil biogeochemistry observed during carrion decomposition return to background or starting conditions shortly after soft tissues are degraded, some biogeochemical parameters, particularly bulk soil stable δ15N isotopic composition, have the potential to exhibit prolonged perturbations, extending for several years. The goal of this study was to evaluate the lateral and vertical changes to soil stable isotopic composition one year after carrion decomposition in a forest ecosystem. Lateral transects extending 140 cm from three decomposition hotspots were sampled at 20 cm intervals, and subsurface cores were collected beneath each hotspot to a depth of 50 cm. Bulk soil stable isotopic composition (δ15N and δ13C) indicated that one year after complete soft tissue removal and decay, soils were significantly 15N-enriched compared to control soils up to 60 cm from the hotspot center, and enrichment extended to a depth of 10 cm. Our results demonstrate that carrion decomposition has the potential to result in long-term changes to soil biogeochemistry, up to at least one year after soft tissue degradation, and to contribute to bulk soil stable isotopic composition.

Seasonal trends in the stable isotopic composition of snow and meltwater runoff in a subarctic catchment at Okstindan, Norway

2004 ◽  
Vol 35 (2) ◽  
pp. 119-137 ◽  
Author(s):  
S.D. Gurney ◽  
D.S.L. Lawrence
Keyword(s):  
Isotopic Composition ◽  
Mean Value ◽  
Mean Values ◽  
Stable Isotopic Composition ◽  
Meltwater Runoff ◽  
Stable Isotopic ◽  
The Mean ◽  
The Difference ◽  
Δ18o And Δd

Seasonal variations in the stable isotopic composition of snow and meltwater were investigated in a sub-arctic, mountainous, but non-glacial, catchment at Okstindan in northern Norway based on analyses of δ18O and δD. Samples were collected during four field periods (August 1998; April 1999; June 1999 and August 1999) at three sites lying on an altitudinal transect (740–970 m a.s.l.). Snowpack data display an increase in the mean values of δ18O (increasing from a mean value of −13.51 to −11.49‰ between April and August), as well as a decrease in variability through the melt period. Comparison with a regional meteoric water line indicates that the slope of the δ18O–δD line for the snowpacks decreases over the same period, dropping from 7.49 to approximately 6.2.This change points to the role of evaporation in snowpack ablation and is confirmed by the vertical profile of deuterium excess. Snowpack seepage data, although limited, also suggest reduced values of δD, as might be associated with local evaporation during meltwater generation. In general, meltwaters were depleted in δ18O relative to the source snowpack at the peak of the melt (June), but later in the year (August) the difference between the two was not statistically significant. The diurnal pattern of isotopic composition indicates that the most depleted meltwaters coincide with the peak in temperature and, hence, meltwater production.

Alkaline soil pH affects bulk soil, rhizosphere and root endosphere microbiomes of plants growing in a Sandhills ecosystem

2021 ◽  
Vol 97 (4) ◽  
Author(s):  
Lucas Dantas Lopes ◽  
Jingjie Hao ◽  
Daniel P Schachtman
Keyword(s):  
Microbial Communities ◽  
Plant Species ◽  
Soil Ph ◽  
Soil Microbial Communities ◽  
Bulk Soil ◽  
Strong Impact ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Soil Microbial ◽  
Soil Rhizosphere

ABSTRACT Soil pH is a major factor shaping bulk soil microbial communities. However, it is unclear whether the belowground microbial habitats shaped by plants (e.g. rhizosphere and root endosphere) are also affected by soil pH. We investigated this question by comparing the microbial communities associated with plants growing in neutral and strongly alkaline soils in the Sandhills, which is the largest sand dune complex in the northern hemisphere. Bulk soil, rhizosphere and root endosphere DNA were extracted from multiple plant species and analyzed using 16S rRNA amplicon sequencing. Results showed that rhizosphere, root endosphere and bulk soil microbiomes were different in the contrasting soil pH ranges. The strongest impact of plant species on the belowground microbiomes was in alkaline soils, suggesting a greater selective effect under alkali stress. Evaluation of soil chemical components showed that in addition to soil pH, cation exchange capacity also had a strong impact on shaping bulk soil microbial communities. This study extends our knowledge regarding the importance of pH to microbial ecology showing that root endosphere and rhizosphere microbial communities were also influenced by this soil component, and highlights the important role that plants play particularly in shaping the belowground microbiomes in alkaline soils.

Prediction method for determining the carbon stable isotopic composition of berry sugars in the original must of Chardonnay wines

2021 ◽  
pp. 130854
Author(s):  
Fumikazu Akamatsu ◽  
Hideaki Shimizu ◽  
Yukari Igi ◽  
Aya Kamada ◽  
Kazuya Koyama ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Prediction Method ◽  
Stable Isotopic Composition ◽  
Stable Isotopic

scholarly journals Stable isotopic composition of top consumers in Arctic cryoconite holes: revealing divergent roles in a supraglacial trophic network

2021 ◽  
Vol 18 (5) ◽  
pp. 1543-1557
Author(s):  
Tereza Novotná Jaroměřská ◽  
Jakub Trubač ◽  
Krzysztof Zawierucha ◽  
Lenka Vondrovicová ◽  
Miloslav Devetter ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Isotopic Ratio ◽  
Isotopic Fractionation ◽  
Mechanistic Explanation ◽  
High Arctic ◽  
Biologically Active ◽  
Glacier Surface ◽  
Stable Isotopic Composition ◽  
Stable Isotopic ◽  
Trophic Network

Abstract. Arctic cryoconite holes represent highly biologically active aquatic habitats on the glacier surface characterized by the dynamic nature of their formation and functioning. The most common cryoconite apex consumers are the cosmopolitan invertebrates – tardigrades and rotifers. Several studies have highlighted the potential relevance of tardigrades and rotifers to cryoconite holes' ecosystem functioning. However, due to the dominant occurrence of prokaryotes, these consumers are usually out of the major scope of most studies aimed at understanding biological processes on glaciers. The aim of this descriptive study is to present pioneering data on isotopic composition of tardigrades, rotifers and cryoconite from three High Arctic glaciers in Svalbard and discuss their role in a cryoconite hole trophic network. We found that tardigrades have lower δ15N values than rotifers, which indicates different food requirements or different isotopic fractionation of both consumers. The δ13C values revealed differences between consumers and organic matter in cryoconite among glaciers. However, the mechanistic explanation of these variations requires further investigation focused on the particular diet of cryoconite consumers and their isotopic ratio. Our study introduces the first observation of carbon and nitrogen stable isotopic composition of top consumers in cryoconite holes analysed by an improved method for cryoconite sample processing, paving the way for further studies of the supraglacial trophic network.

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