Nitrogen cycling and export in California chaparral: the role of climate in shaping ecosystem responses to fire

2016 ◽  
Vol 87 (1) ◽  
pp. 76-90 ◽  
Author(s):  
Erin J. Hanan ◽  
Christina Naomi Tague ◽  
Joshua P. Schimel
Keyword(s):  
Nitrogen Cycling ◽  
Ecosystem Responses

scholarly journals Soil moisture dominates dryness stress on ecosystem production globally

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Laibao Liu ◽  
Lukas Gudmundsson ◽  
Mathias Hauser ◽  
Dahe Qin ◽  
Shuangcheng Li ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Vapor Pressure Deficit ◽  
Arid Ecosystems ◽  
Drought Risk ◽  
Relative Role ◽  
Ecosystem Responses ◽  
Vegetation Growth ◽  
Ecosystem Production ◽  
Valid Data

Abstract Dryness stress can limit vegetation growth and is often characterized by low soil moisture (SM) and high atmospheric water demand (vapor pressure deficit, VPD). However, the relative role of SM and VPD in limiting ecosystem production remains debated and is difficult to disentangle, as SM and VPD are coupled through land-atmosphere interactions, hindering the ability to predict ecosystem responses to dryness. Here, we combine satellite observations of solar-induced fluorescence with estimates of SM and VPD and show that SM is the dominant driver of dryness stress on ecosystem production across more than 70% of vegetated land areas with valid data. Moreover, after accounting for SM-VPD coupling, VPD effects on ecosystem production are much smaller across large areas. We also find that SM stress is strongest in semi-arid ecosystems. Our results clarify a longstanding question and open new avenues for improving models to allow a better management of drought risk.

The role of the atmosphere in nitrogen cycling

1982 ◽  
Vol 67 (1-3) ◽  
pp. 61-71 ◽  
Author(s):  
E. Sanhueza
Keyword(s):  
Nitrogen Cycling

scholarly journals Micro-aggregation of a pristine grassland soil selects for bacterial and fungal communities and changes in nitrogen cycling potentials

2021 ◽  
Author(s):  
Christoph Keuschnig ◽  
Jean Martins ◽  
Aline Navel ◽  
Pascal Simonet ◽  
Catherine Larose
Keyword(s):  
Particle Size ◽  
Nitrogen Cycling ◽  
Bacterial Communities ◽  
Soil Microbial Communities ◽  
Microbial Interactions ◽  
Fungal Communities ◽  
Supernatant Fraction ◽  
Soil Microbial ◽  
Microbial Analysis

Microbial analysis at the micro scale of soil is essential to the overall understanding of microbial organization and interactions, and necessary for a better understanding of soil ecosystem functioning. While bacterial communities have been extensively described, little is known about the organization of fungal communities as well as functional potentials at scales relevant to microbial interactions. Fungal and bacterial communities and changes in nitrogen cycling potentials in the pristine Rothamsted Park Grass soil (bulk soil) as well as in its particle size sub-fractions (PSFs; > 250 µm, 250-63 µm, 63-20 µm, 20-2 µm, < 2 µm and supernatant) were studied. The potential for nitrogen reduction was found elevated in bigger aggregates. The relative abundance of Basidiomycota deceased with decreasing particle size, Ascomycota showed an increase and Mucoromycota became more prominent in particles less than 20 µm. Bacterial community structures changed below 20 µm at the scale where microbes operate.Strikingly, only members of two bacterial and one fungal phyla (Proteobacteria, Bacteroidota and Ascomycota, respectively) were washed-off the soil during fractionation and accumulated in the supernatant fraction where most of the detected bacterial genera (e.g., Pseudomonas, Massilia, Mucilaginibacter, Edaphobaculum, Duganella, Janthinobacterium and Variovorax) were previously associated with exopolysaccharide production and biofilm formation.Overall, the applied method shows potential to study soil microbial communities at micro scales which might be useful in studies focusing on the role of specific fungal taxa in soil structure formation as well as research on how and by whom biofilm-like structures are distributed and organized in soil.

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