Soil formation, nutrient supply and ecosystem productivity on basaltic lava vs rhyolitic pumice on Alcedo Volcano, Galápagos

Soil Research ◽  
2021 ◽  
Author(s):  
Franz Zehetner ◽  
Heinke Jäger ◽  
Katharina M. Keiblinger ◽  
Tamara C. Dinter ◽  
I. Nyoman Candra ◽  
...  
1988 ◽  
Vol 19 ◽  
pp. 123-131 ◽  
Author(s):  
J. M. Anketell ◽  
S. M. Ghellali

AbstractThe Qasr Al Haj Formation, comprised of alluvial fan gravels and sands with calcrete horizons, is subdivided into five members separated one from the other by surfaces of discontinuity. These surfaces, defined primarily by erosion and soil formation, can be followed northwards into the Jifarah Formation thus allowing detailed correlation of the fan-gravel deposits with the finer fluvio-aeolian sands and silts of the floodplain. Thick deposits of cemented and uncemented gravels at Wadi Ghan contain at least two horizons of basaltic lava flows. Previously reported finds of artifacts from this gravel sequence together with the possibility of radiometric dating of the lavas, may provide a much-needed chronostratigraphic framework for the Quaternary deposits of the north-west Tripolitanian region.


2020 ◽  
Vol 85 ◽  
pp. 47-58
Author(s):  
Y Jiang ◽  
Y Liu

Various studies have observed that increased nutrient supply promotes the growth of bloom-forming cyanobacteria, but only a limited number of studies have investigated the influence of increased nutrient supply on bloom-forming cyanobacteria at the proteomic level. We investigated the cellular and proteomic responses of Microcystis aeruginosa to elevated nitrogen and phosphorus supply. Increased supply of both nutrients significantly promoted the growth of M. aeruginosa and the synthesis of chlorophyll a, protein, and microcystins. The release of microcystins and the synthesis of polysaccharides negatively correlated with the growth of M. aeruginosa under high nutrient levels. Overexpressed proteins related to photosynthesis, and amino acid synthesis, were responsible for the stimulatory effects of increased nutrient supply in M. aeruginosa. Increased nitrogen supply directly promoted cyanobacterial growth by inducing the overexpression of the cell division regulatory protein FtsZ. NtcA, that regulates gene transcription related to both nitrogen assimilation and microcystin synthesis, was overexpressed under the high nitrogen condition, which consequently induced overexpression of 2 microcystin synthetases (McyC and McyF) and promoted microcystin synthesis. Elevated nitrogen supply induced the overexpression of proteins involved in gas vesicle organization (GvpC and GvpW), which may increase the buoyancy of M. aeruginosa. Increased phosphorus level indirectly affected growth and the synthesis of cellular substances in M. aeruginosa through the mediation of differentially expressed proteins related to carbon and phosphorus metabolism. This study provides a comprehensive description of changes in the proteome of M. aeruginosa in response to an increased supply of 2 key nutrients.


2006 ◽  
Vol 34 (1) ◽  
pp. 569-572
Author(s):  
M. Lesznyák ◽  
Borbély Hunyadi

2020 ◽  
Vol 71 (1) ◽  
pp. 192-200
Author(s):  
Anca-Luiza Stanila ◽  
Catalin Cristian Simota ◽  
Mihail Dumitru

Highlighting the sandy soil of Oltenia Plain calls for a better knowledge of their variability their correlation with major natural factors from each physical geography. Pedogenetic processes specific sandy soils are strongly influenced by nature parent material. This leads, on the one hand, climate aridity of the soil due to strong heating and accumulation of small water reserves, consequences emphasizing the moisture deficit in the development of the vegetation and favoring weak deflation, and on the other hand, an increase in mineralization organic matter. Relief under wind characteristic sandy land, soil formation and distribution has some particularly of flat land with the land formed on the loess. The dune ridges are less evolved soils, profile underdeveloped and poorly supplied with nutrients compared to those on the slopes of the dunes and the interdune, whose physical and chemical properties are more favorable to plant growth.Both Romanati Plain and the Blahnita (Mehedinti) Plain and Bailesti Plain, sand wind shaped covering a finer material, loamy sand and even loess (containing up to 26% clay), also rippled with negative effects in terms of overall drainage. Depending on the pedogenetic physical and geographical factors that have contributed to soil cover, in the researched were identified following classes of soils: protisols, cernisols, cambisols, luvisols, hidrisols and antrosols.Obtaining appropriate agricultural production requires some land improvement works (especially fitting for irrigation) and agropedoameliorative works. Particular attention should be paid to preventing and combating wind erosion.


Soil Horizons ◽  
1992 ◽  
Vol 33 (3) ◽  
pp. 70 ◽  
Author(s):  
Simonson Roy W.

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