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711.
Su Teng Ahmad Ishtiaq Qayyum Abdul Yin Weihua Rahman Saeed ur Adeel-Farooq Rana Muhammed 《Environmental science and pollution research international》2021,28(47):66930-66940
Environmental Science and Pollution Research - Energy consumption is widely regarded as the primary driver of economic development and environmental degradation. The current study examines how... 相似文献
712.
We report that iron-reducing bacteria are primary mediators of anaerobic carbon oxidation in upland tropical soils spanning a rainfall gradient (3500-5000 mm/yr) in northeast Puerto Rico. The abundant rainfall and high net primary productivity of these tropical forests provide optimal soil habitat for iron-reducing and iron-oxidizing bacteria. Spatially and temporally dynamic redox conditions make iron-transforming microbial communities central to the belowground carbon cycle in these wet tropical forests. The exceedingly high abundance of iron-reducing bacteria (up to 1.2 x 10(9) cells per gram soil) indicated that they possess extensive metabolic capacity to catalyze the reduction of iron minerals. In soils from the higher rainfall sites, measured rates of ferric iron reduction could account for up to 44% of organic carbon oxidation. Iron reducers appeared to compete with methanogens when labile carbon availability was limited. We found large numbers of bacteria that oxidize reduced iron at sites with high rates of iron reduction and large numbers of iron reducers. The coexistence of large populations of iron-reducing and iron-oxidizing bacteria is evidence for rapid iron cycling between its reduced and oxidized states and suggests that mutualistic interactions among these bacteria ultimately fuel organic carbon oxidation and inhibit CH4 production in these upland tropical forests. 相似文献
713.
Species in a given trophic level occur in vastly unequal abundance, a pattern commonly documented but poorly explained for most taxa. Theoretical predictions of species density such as those arising from the metabolic theory of ecology hold well at large spatial and temporal scales but are not supported in many communities sampled at a relatively small scale. At these scales ecological factors may be more important than the inherent limits to energy use set by allometric scaling of mass. These factors include the amount of resources available, and the ability of individuals to convert these resources successfully into population growth. While previous studies have demonstrated the limits of macroecological theory in explaining local abundance, few studies have tested alternative generalized mechanisms determining abundance at the community scale. Using an assemblage of forest moth species found co-occurring as caterpillars on a single host plant species, we tested whether species abundance on that plant could be explained by mass allometry, intrinsic population growth, diet breadth, or some combination of these traits. We parameterized life history traits of the caterpillars in association with the host plant in both field and laboratory settings, so that the population growth estimate was specific to the plant on which abundance was measured. Using a generalized least-squares regression method incorporating phylogenetic relatedness, we found no relationship between abundance and mass but found that abundance was best explained by both intrinsic population growth rate and diet breadth. Species population growth potential was most affected by survivorship and larval development time on the host plant. Metabolic constraints may determine upper limits to local abundance levels for species, but local community abundance is strongly predicted by the potential for population increase and the resources available to that species in the environment. 相似文献
714.
Wuxing Liu Yongming Luo Ying Teng Zhengao Li Lena Q. Ma 《Environmental geochemistry and health》2010,32(1):23-29
In situ bioremediation of oily sludge-contaminated soil by biostimulation of indigenous microbes through adding manure was
conducted at the Shengli oilfield in northern China. After bioremediation for 360 days, total petroleum hydrocarbon (TPH)
content was reduced by 58.2% in the treated plots compared with only 15.6% in the control plot. Moreover, bioremediation significantly
improved the physicochemical properties of the soil in the treated plot. Soil microbial counts and community-level physiological
profiling were also examined. Manure addition increased TPH degraders and polycyclic aromatic hydrocarbon (PAH) degraders
in the contaminated soil by one to two orders of magnitude. The activity and biodiversity of soil microbial communities also
increased markedly in the treated plot compared with that of the control. Finally, biotoxicity was used to evaluate the soils
and a sharp increase in the EC50 of the soil after bioremediation was observed, indicating that bioremediation had reduced
the toxicity of the soil. 相似文献
715.
Eric Parmentier Loïc Kéver Margarida Casadevall David Lecchini 《Marine Biology》2010,157(10):2317-2327
Synchronous underwater audio–video recordings and a passive acoustic detector were used to study the behaviour of Dascyllus flavicaudus. These damselfish produced sounds during six different behaviours and showed three different colour patterns while doing
so. These sounds can be grouped into three classes: sounds associated with (1) fighting; (2) mating/visiting and (3) chasing
and signal jumps. Moreover, the evolution of the different kinds of sound is discussed: the first calls could be a single
pulse originating in teeth snapping. Modifications in the rhythm and number of pulses allowed the fish to build new messages.
Daily recordings showed that sound production rates were higher at sunrise and sunset than during the day and that no sound
was produced during the night. However, the kinds of call were different: sunrise sounds seemed mainly associated with mating/visiting,
whereas the sounds associated with chasing and to signal jumps were mainly found at sunset. 相似文献
716.
Jeffrey N. Schinske Giacomo Bernardi David K. Jacobs Eric J. Routman 《Marine Biology》2010,157(1):123-134
We compared morphology and sequenced nuclear and mitochondrial genes from 11 populations of a previously genetically unstudied
“Baja California disjunct” species, the diamond turbot (Hypsopsetta guttulata). This species exhibits very limited adult movement and restriction to soft-bottom habitats but has a moderately long pelagic
larval duration. Therefore, if pelagic larval duration is correlated with gene flow between Gulf of California and Pacific
populations, we expect a reduced level of genetic and morphological differentiation. However, if adult habitat and ecology
have more effect on gene flow, we expect the populations in the two bodies of water to be more highly differentiated. We used
logistic regression to compare morphological features and phylogenetic and population genetic analyses to compare nucleotide
sequence data. Gulf of California H. guttulata are different from Pacific populations in morphology and both mitochondrial and nuclear gene sequences. MtDNA shows reciprocal
monophyly, and nuclear sequences from the Gulf of California formed a monophyletic group. Population genetic analyses also
suggest further population subdivision within the Pacific and within the Gulf of California. We argue that adult ecology has
a significant effect on migration rates among populations in the Pacific Ocean and the Gulf of California. 相似文献
717.
Inverse parameter estimation of individual-based models (IBMs) is a research area which is still in its infancy, in a context where conventional statistical methods are not well suited to confront this type of models with data. In this paper, we propose an original evolutionary algorithm which is designed for the calibration of complex IBMs, i.e. characterized by high stochasticity, parameter uncertainty and numerous non-linear interactions between parameters and model output. Our algorithm corresponds to a variant of the population-based incremental learning (PBIL) genetic algorithm, with a specific “optimal individual” operator. The method is presented in detail and applied to the individual-based model OSMOSE. The performance of the algorithm is evaluated and estimated parameters are compared with an independent manual calibration. The results show that automated and convergent methods for inverse parameter estimation are a significant improvement to existing ad hoc methods for the calibration of IBMs. 相似文献
718.
The fate of reactive tracers is often modelled by depth-averaged equations. When integrating the depth-resolved equations, it appears that the term describing the settling of particles is dependent on the concentration just above the bottom. Because in a depth-averaged framework this quantity is not available, the settling term needs to be parameterised. The most natural choice is to make the settling flux dependent on the average concentration. This approximation is acceptable if the water column is well mixed, but these conditions are not necessarily met in real applications. Therefore, this study aims at assessing and understanding the error made by using a depth-averaged model in a range of realistic conditions. For the definition of these conditions, typical values for the Scheldt Estuary and the Dutch-Belgian coast were taken. The realistic inspiration for the reactive tracer in this study is the fecal bacterium Escherichia coli, whose own dynamics are characterised by settling and gradual decay by mortality. In an attempt to understand the relative importance of several factors like settling, mortality, mixing and stratification on the error made by a depth-averaged approach, a number of simplified test cases were investigated. It follows that, as expected, the error is acceptable if the situation is mixing-dominated. However, the effect of mortality and stratification was less obvious in advance. For instance, it appeared that errors can also be significant if settling and mortality have the same characteristic timescales. Stratification often has the effect to increase the error made by the depth-averaged model. 相似文献
719.
脱硫渣废弃物对盐碱地油葵根际微生物数量及土壤酶活性的影响 总被引:3,自引:0,他引:3
通过大田实验,研究了不同脱硫渣废弃物对油葵(Helianthus annuus)根际微生物数量和酶活性的影响。结果表明:随着生育期的进行,微生物总量在苗期和花期数量较少,成熟期是数量较多。脱硫渣施用量对油葵根际微生物数量及酶活性均产生影响,微生物总量和油葵根际土壤酶活性均随着脱硫渣施用量的增加呈现出先升高后下降的趋势,同一生育期内,微生物总量以C(1.5 t/hm2)或D(2.25 t.hm-2)处理的微生物数量较高,B(0.75 t.hm-2)处理时的微生物数量较少;表明施用适量的脱硫渣有益于油葵根际微生物数量和酶活性的提高,过高则导致微生物数量和酶活性下降。 相似文献
720.
胡敏酸、富里酸对土壤-地下水系统中BDE-47迁移的影响 总被引:1,自引:0,他引:1
多溴联苯醚(polybrominated diphenyl ethers,PBDEs)是土壤-地下水系统中广泛存在的有机污染物,研究土壤组分对其迁移行为的影响是解决土壤-地下水系统中多溴联苯醚归趋问题的关键。以典型多溴联苯醚同系物2,2',4,4'-四溴联苯醚(2,2',4,4'-tetrabromodiphenyl ether,BDE-47)为研究对象,选取胡敏酸(humic acid,HA)、富里酸(fulvic acid,FA)2种代表性土壤有机组分,配制不同浓度的FA、HA溶液(150 mg·L~(-1)、50 mg·L~(-1)),分别对不同浓度的BDE-47(100μg·g~(-1)、10μg·g~(-1))污染土壤进行土柱淋滤实验,探讨FA、HA对土壤-地下水系统中BDE-47迁移的影响。结果表明,HA作用下,实验组下层土壤中BDE-47的残留比例分别为0.62%和0.40%,分别低于对照组的0.72%和3.36%;FA作用下,实验组下层土壤中BDE-47的残留比例分别为6.40%和6.71%,分别高于对照组的0.72%和3.36%。结合HA和FA的元素组成和结构特征分析可知,疏水性强的HA能够促进BDE-47随水流迁移进入地下水系统;亲水性强的FA促进BDE-47在土壤系统中的分布,阻滞了土壤系统中BDE-47进入地下水系统。本文为评估HA、FA对土壤-地下水系统中BDE-47迁移的影响提供依据。 相似文献