Responses of microbial activity to carbon, nitrogen, and phosphorus additions in forest mineral soils differing in organic carbon content

2021 ◽  
Vol 57 (4) ◽  
pp. 513-521
Author(s):  
Veronika Jílková ◽  
Kateřina Jandová ◽  
Jaroslav Kukla
2012 ◽  
Vol 63 (11) ◽  
pp. 967 ◽  
Author(s):  
James W. Fourqurean ◽  
Gary A. Kendrick ◽  
Laurel S. Collins ◽  
Randolph M. Chambers ◽  
Mathew A. Vanderklift

Seagrass meadows in Florida Bay and Shark Bay contain substantial stores of both organic carbon and nutrients. Soils from both systems are predominantly calcium carbonate, with an average of 82.1% CaCO3 in Florida Bay compared with 71.3% in Shark Bay. Soils from Shark Bay had, on average, 21% higher organic carbon content and 35% higher phosphorus content than Florida Bay. Further, soils from Shark Bay had lower mean dry bulk density (0.78 ± 0.01 g mL–1) than those from Florida Bay (0.84 ± 0.02 mg mL–1). The most hypersaline regions of both bays had higher organic carbon content in surficial soils. Profiles of organic carbon and phosphorus from Florida Bay indicate that this system has experienced an increase in P delivery and primary productivity over the last century; in contrast, decreasing organic carbon and phosphorus with depth in the soil profiles in Shark Bay point to a decrease in phosphorus delivery and primary productivity over the last 1000 y. The total ecosystem stocks of stored organic C in Florida Bay averages 163.5 MgCorg ha–1, lower than the average of 243.0 MgCorg ha–1 for Shark Bay; but these values place Shark and Florida Bays among the global hotspots for organic C storage in coastal ecosystems.


2021 ◽  
Author(s):  
Caio César Pires de Paula ◽  
Dagmara Sirová ◽  
Hugo Sarmento ◽  
Camila Cesario Fernandes ◽  
Luciano Takeshi Kishi ◽  
...  

AbstractScarce studies on microbial diversity in tropical caves have been published, a subterranean system still neglected from a microbiological point of view. Although most published studies are about temperate caves, usually archaeas and fungi have less attention than bacterial communities. Here, the microbiome structure and composition in a tropical cave system, as well the main environmental drivers, were studied during the wet and dry season. Soil and sediments from three different habitats at the cave (surface, entrance cave and dark zone) were sampled. Samples were characterized (temperature, air and substrate humidity, salinity, pH, nitrogen and organic carbon content, and chemical composition) and the microbiome was assessed by high-throughput sequencing, using amplicon sequencing (16S and ITS). Prokaryotic communities were dominated by Halobacteria, Actinobacteria and Bacilli, while fungal communities showed high abundance of Sordariomycetes. Microbiomes from the cave entrance, where a significantly elevated salinity levels were found, supported up to 63% of Haloarchaea compared to the other habitats studied. Differences in community structure were significant between habitats, but no influence of the season was observed. Main environmental drivers of community assembly included nitrogen and organic carbon content, temperature, and salinity. This is the first report of Halobacteria dominance in cave habitats, where they likely play important roles in nitrogen and phosphorus cycles. The cave entrance had lower diversity, but higher degree of microbial endemism, which characterize it as an important cave ecotone. The prevalence of heterotrophic microbial groups implies trophic structure based on detritivores, particularly in the dark zones. Our study brings new insights on microbiome composition in the underexplored tropical cave habitats.


Soil Research ◽  
1996 ◽  
Vol 34 (6) ◽  
pp. 1041 ◽  
Author(s):  
NS Bolan ◽  
S Baskaran

The adsorption-desorption behaviour and the degradation of an ionic herbicide (2,4-D) were examined using 10 soils from New Zealand that differed in their organic matter and clay content. Adsorption isotherms for 2,4-D were adequately described by the Freundlich isotherm and the values of the exponent N of the Freundlich isotherm were close to 1 (0.92-0.98), indicating that the adsorption isotherm tended to become linear. The extent of adsorption, as measured by the distribution coefficient (Kd), increased with an increase in soil organic carbon. The rate of desorption of 2,4-D followed first-order reaction kinetics with respect to surface concentration, and decreased with an increase in the organic carbon content of the soils. The rate of degradation of 2,4-D, as measured by the half-life (t1/2), decreased with an initial increase in soil organic carbon, which is attributed to the increase in adsorption. With increasing adsorption, the rate of desorption decreased, resulting in a low concentration of 2,4-D in the soil solution that is available for microbial degradation. When the organic carbon content was more than 12%, however, both the adsorption and rate of degradation increased. The enhanced degradation of 2,4-D at these levels of organic carbon may be related to the increased biological activity of the soil, as measured by substrate-induced respiration, and the decreased 2,4-D-induced inhibitory effect on microbial activity.


2003 ◽  
Vol 266 (2) ◽  
pp. 251-258 ◽  
Author(s):  
Shannon L. Bartelt-Hunt ◽  
Susan E. Burns ◽  
James A. Smith

2021 ◽  
Vol 24 ◽  
pp. e00367
Author(s):  
Patrick Filippi ◽  
Stephen R. Cattle ◽  
Matthew J. Pringle ◽  
Thomas F.A. Bishop

Author(s):  
Emmanuelle Vaudour ◽  
Cécile Gomez ◽  
Philippe Lagacherie ◽  
Thomas Loiseau ◽  
Nicolas Baghdadi ◽  
...  

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