scholarly journals Effects of termites growth on litter decomposition: a modeling approach

2019 ◽  
Vol 8 (S1) ◽  
pp. 415-421
Author(s):  
Abdourhimou amadou Issoufou ◽  
Idrissa Soumana ◽  
Garba Maman ◽  
Souleymane Konate ◽  
Ali Mahamane
Keyword(s):  
Litter Decomposition ◽  
Arid Regions ◽  
Soil Nutrient ◽  
Population Level ◽  
Significant Activity ◽  
Soil Environment ◽  
Degradation Rates ◽  
Soil Nutrient Cycling ◽  
Fungus Comb ◽  
The Difference

Abstract Purpose Litter decomposition is a biological process resulting from enzymatic activities of microorganisms and influenced in a variety of ways by activities of termites in semi-arid regions. We presented a general model of the decomposition process from litter to carbon sequestration and nitrogen. We aimed at building a termite population growth model which could deal with one substrate. Methods Our model divides the decomposition/growth process at the population level. We put these changes into equations using an analogy with chemical reactions at equilibrium. Results Our findings provide evidence that activities of termites can promote the significant activity of microbial decomposers and increase degradation rates of soil organic matter (SOM). Also, termite activity was probably an additional contributor to the difference between fungus-comb chamber and soil environment, in which the fungus-comb compartment was positively related to carbon and nutrients release. According to the developed, observed differences in decomposition rate, changes were strongly affected by the termite communities’ activities in the two types of compartment. Conclusion This functional distinction highlights the importance of termites’ activities on microbial activities stimulation through their development featuring their impacts on soil nutrient cycling.

scholarly journals Plant secondary metabolites: a key driver of litter decomposition and soil nutrient cycling

2016 ◽  
Vol 104 (6) ◽  
pp. 1527-1541 ◽  
Author(s):  
Mathilde Chomel ◽  
Marie Guittonny‐Larchevêque ◽  
Catherine Fernandez ◽  
Christiane Gallet ◽  
Annie DesRochers ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Nutrient Cycling ◽  
Litter Decomposition ◽  
Plant Secondary Metabolites ◽  
Soil Nutrient ◽  
Soil Nutrient Cycling ◽  
Key Driver

Cranial crassicaudiasis in two coastal dolphin species from South Africa is predominantly a disease of immature individuals

2020 ◽  
Vol 139 ◽  
pp. 93-102 ◽  
Author(s):  
MF Van Bressem ◽  
P Duignan ◽  
JA Raga ◽  
K Van Waerebeek ◽  
N Fraijia-Fernández ◽  
...  
Keyword(s):  
South Africa ◽  
Bone Development ◽  
Bottlenose Dolphins ◽  
Fatal Outcome ◽  
Population Level ◽  
Cape Coast ◽  
Osteolytic Lesions ◽  
Immune Mediated ◽  
Significant Difference ◽  
The Difference

Crassicauda spp. (Nematoda) infest the cranial sinuses of several odontocetes, causing diagnostic trabecular osteolytic lesions. We examined skulls of 77 Indian Ocean humpback dolphins Sousa plumbea and 69 Indo-Pacific bottlenose dolphins Tursiops aduncus, caught in bather-protecting nets off KwaZulu-Natal (KZN) from 1970-2017, and skulls of 6 S. plumbea stranded along the southern Cape coast in South Africa from 1963-2002. Prevalence of cranial crassicaudiasis was evaluated according to sex and cranial maturity. Overall, prevalence in S. plumbea and T. aduncus taken off KZN was 13 and 31.9%, respectively. Parasitosis variably affected 1 or more cranial bones (frontal, pterygoid, maxillary and sphenoid). No significant difference was found by gender for either species, allowing sexes to be pooled. However, there was a significant difference in lesion prevalence by age, with immature T. aduncus 4.6 times more likely affected than adults, while for S. plumbea, the difference was 6.5-fold. As severe osteolytic lesions are unlikely to heal without trace, we propose that infection is more likely to have a fatal outcome for immature dolphins, possibly because of incomplete bone development, lower immune competence in clearing parasites or an over-exuberant inflammatory response in concert with parasitic enzymatic erosion. Cranial osteolysis was not observed in mature males (18 S. plumbea, 21 T. aduncus), suggesting potential cohort-linked immune-mediated resistance to infestation. Crassicauda spp. may play a role in the natural mortality of S. plumbea and T. aduncus, but the pathogenesis and population level impact remain unknown.

scholarly journals Diversity Scaling of Human Digestive Tract (DT) Microbiomes: The Intra-DT and Inter-individual Patterns

2021 ◽  
Vol 12 ◽  
Author(s):  
Hongju (Daisy) Chen ◽  
Bin Yi ◽  
Qiang Liu ◽  
Xia Xu ◽  
Lin Dai ◽  
...  
Keyword(s):  
Digestive Tract ◽  
Bacterial Species ◽  
Population Level ◽  
Individual Heterogeneity ◽  
Scaling Parameter ◽  
Genus Richness ◽  
Species Area ◽  
The Difference ◽  
Human Digestive Tract ◽  
Biodiversity Changes

The human gut microbiome has been extensively studied, but its diversity scaling (changes or heterogeneities) along the digestive tract (DT) as well as their inter-individual heterogeneities have not been adequately addressed to the best of our knowledge. Here we fill the gap by applying the diversity-area relationship (DAR), a recent extension to the classic species-area relationship (SAR) in biogeography, by reanalyzing a dataset of over 2000 16s-rRNA microbiome samples obtained from 10 DT sites of over 200 individuals. We sketched out the biogeography “maps” for each of the 10 DT sites by cross-individual DAR analysis, and the intra-DT distribution pattern by cross-DT-site DAR analysis. Regarding the inter-individual biogeography, it was found that all DT sites have the invariant (constant) scaling parameter—all sites possessing the same diversity change rate across individuals, but most sites have different potential diversities, which include the portions of diversity that may be absent locally but present regionally. In the case of this study, the potential diversity of each DT site covers the total diversity of the respective site from all individuals in the cohort. In terms of the genus richness, an average individual hosts approximately 20% of the population-level genus richness (total bacterial genus of a human population). In contrast, in terms of community biodiversity, the percentages of individual over population may exceed 90%. This suggests that the differences between individuals in their DT microbiomes are predominantly in the composition of bacterial species, rather than how their abundances are distributed (i.e., biodiversity). Regarding the intra-DT patterns, the scaling parameter (z) is larger—suggesting that the intra-DT biodiversity changes are larger than inter-individual changes. The higher intra-DT heterogeneity of bacteria diversity, as suggested by larger intra-DT z than the inter-individual heterogeneity, should be expected since the intra-DT heterogeneity reflects the functional differentiations of the DT tract, while the inter-individual heterogeneity (z) reflects the difference of the same DT site across individuals. On average, each DT site contains 21–36% of the genus diversity of the whole DT, and the percentages are even higher in terms of higher taxon levels.

Biogeography of island floras in the Great Lakes. I. Species richness and composition in relation to gull nesting activities

1989 ◽  
Vol 67 (4) ◽  
pp. 961-969 ◽  
Author(s):  
E. H. Hogg ◽  
J. K. Morton ◽  
Joan M. Venn
Keyword(s):  
Species Richness ◽  
Great Lakes ◽  
Plant Species ◽  
Vascular Plants ◽  
Soil Nutrient ◽  
Lake Huron ◽  
Great Lakes Region ◽  
Alien Plant ◽  
Species Area ◽  
The Difference

Species–area relations of vascular plants and the effect of nesting colonies of gulls on plant species composition were investigated for 77 islands in Georgian Bay and Lake Huron in the Great Lakes region of Canada. The percentage of plant species classed as alien, annual, or biennial was significantly greater on islands with gull colonies. The slope of the species–area curve was significantly steeper on islands supporting gull colonies compared with islands lacking gull colonies. The expected decline in species richness with increased island remoteness was not detected statistically using multiple regression analysis. The difference in species–area slopes does not appear to reflect a lower propagule immigration rate to islands with gull colonies, because gulls are important in the dispersal of alien plant species to these islands. Larger islands with gull colonies tended to have richer floras than islands of similar size without gull colonies. It is suggested that on these larger islands the presence of gull colonies produces a gradient of soil nutrient and disturbance regimes, thus increasing habitat heterogeneity and species richness.

Biodegradation Rate of Chloroethylene in Soil Environment

1992 ◽  
Vol 25 (11) ◽  
pp. 419-424 ◽  
Author(s):  
O. Yagi ◽  
H. Uchiyama ◽  
K. Iwasaki
Keyword(s):  
Soil Solution ◽  
Substrate Concentration ◽  
Material Balance ◽  
Field Soil ◽  
Soil Environment ◽  
Biodegradation Rate ◽  
Vegetable Field ◽  
Degradation Rates ◽  
Field Soils ◽  
Degradation Time

Degradation rates of PCE and TCE were determined in lotus, rice and vegetable field soils. The lotus field soil had the highest ability to degrade tetrachloroethylene(PCE) and trichloroethylene(TCE). The values of T50(50% degradation time) in L-1 lotus soil were 8 and 15 days for PCE and TCE under the substrate concentration of 5 µg in 50ml of soil solution. PCE was biologically transformed to TCE in all soils. The material balance of PCE depletion and TCE production were determined. The degradation rates of PCE and TCE were significantly influenced by temperature and substrate concentration.

scholarly journals Fertimetro, a Principle and Device to Measure Soil Nutrient Availability for Plants by Microbial Degradation Rates on Differently-Spiked Buried Threads

Soil Systems ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 3 ◽  
Author(s):  
Giuseppe Concheri ◽  
Stefano Tiozzo ◽  
Piergiorgio Stevanato ◽  
Francesco Morari ◽  
Antonio Berti ◽  
...  
Keyword(s):  
Crop Yields ◽  
Soil Nutrient ◽  
Self Assessment ◽  
Soil Nutrient Availability ◽  
Degradation Rates ◽  
Subsequent Crop ◽  
User Friendly ◽  
Fertilizer Rates ◽  
Kinetics Of

A novel patented method (PCT/IB2012/001157: Squartini, Concheri, Tiozzo, University of Padova) and the corresponding application devices, suitable to measure soil fertility, are presented. The availability or deficiency of specific nutrients for crops is assessed by monitoring the kinetics of progressive weakening of cotton or silk threads due to in situ microbial activity. The method is based on a nutrient-primed incremented substrate degradation principle. Threads are buried as is or pre-impregnated with N or P solutions, and the acceleration of the degradation rate for the N-supplemented or P-supplemented thread, in comparison to the untreated thread, is proportional to the lack of the corresponding nutrient in that soil. Tests were validated on corn crops in plots receiving increasing fertilizer rates in a historical rotation that has been established since 1962. The measurement carried out in May significantly correlated with the subsequent crop yields recorded in October. The analysis allows an early, inexpensive, fast, and reproducible self-assessment at field level to improve fertilization rates. The device is envisaged as a user-friendly tool for agronomy, horticulture, and any environmental applications where organic matter cycling, soil quality, and specific nutrients excess or deficiency are critical considerations.

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