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![(a) Example of closed-static chambers used in GHG flux sampling from soil. Gas samples are collected using a syringe at a regular interval to facilitate gas flux calculation. (b) Example of flow-through chamber. The chamber has a connections chain of Polyethylene (plastic) skirt placed on soil surface. The chamber is monitoring GHG flux via an infrared analyser. Separate gas samples can be taken using a syringe as in (a) through a membrane for GHG analyses. Photo: Adopted from [28].](profile/Saadu-Wali/publication/343022353/figure/fig1/AS:914406917550080@1595023006647/a-Example-of-closed-static-chambers-used-in-GHG-flux-sampling-from-soil-Gas-samples.png)
(a) Example of closed-static chambers used in GHG flux sampling from soil. Gas samples are collected using a syringe at a regular interval to facilitate gas flux calculation. (b) Example of flow-through chamber. The chamber has a connections chain of Polyethylene (plastic) skirt placed on soil surface. The chamber is monitoring GHG flux via an infrared analyser. Separate gas samples can be taken using a syringe as in (a) through a membrane for GHG analyses. Photo: Adopted from [28].
Source publication
Despite the significant developments in methodological approaches to greenhouse gas (GHG) flux measurements, the selection of best method for GHG flux research remain very difficult owing to the fact that nearly all the approved methodologies have some observed limitations that affect the accuracy of flux measurements. In this short review, a compa...
Contexts in source publication
Context 1
... fundamental principle involved in measuring trace gas concentration after chamber deployment is that gas samples are drawn from the chamber over the order of one hour [30]. Simple design of a closed chamber is exemplified in Figure 1. ...
Context 2
... further argued that the correction methods of Hutchinson and Mosier do not account for increasing gas concentrations in the soil profile. However, in flowthrough system (Figure 1b), gas concentration gradient stabilizes, and emissions differ very slightly from the original situation. In addition, laboratory analysis indicates that a closed-static absorption method is not capable of absorbing all the effluxes between sampled gases and caustic solution [35]. ...
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... The large-scale observation of soaring temperatures may correlate to a natural warming phase, which began in the 19 th century. Anthropogenic greenhouse gas releases further accelerate it from burning fossil fuels and emissions from wetlands [20][21][22][23][24]. The general fear raised by global heating is that climatic change can modify the hydrological cycle; indeed, numerous investigations have shown that the water cycle has been altered. ...
Groundwater development in arid and semiarid regions is accelerated by expanded irrigation farming, industrialisation, and municipal water supply. This study provides a detailed hydrogeological analysis of sedimentary aquifers of the Sokoto basin, Northwestern Nigeria, for improved water resource development and management. Hydrogeological data, including static water level (Swl), pumping water level (Pwl), pumping test (Pt), and estimated yield (Ey), were analysed. A total of three hundred (300) observations on Swl, Pt, Pwl, Ey, and Hps were derived from boreholes and analysed using Factor analysis (FA) and Regression analysis (RA). Results showed that Gwandu Formation is the most prolific aquifer. Boreholes can yield more than 24000 litres per hour (L/h). This was followed by The Kalambaina limestone aquifer, which has the potential to yield about 15000 (L/h). However, the Taloka Formation is characterised by very poor aquifers in most of the basin, though along the Jega-Dogon Daji axis, boreholes can yield more than 24000 (L/h). Likewise, boreholes tapping the Wurno Formation can produce a maximum yield of 24000 (L/h). Estimated yields from boreholes were less than 1500 (L/h) from the Gundumi aquifer, and the maximum borehole yields were 17760 (L/h) in the Illo aquifer. Statistical modelling showed that all the analysed variables are significant concerning groundwater potentials and variability of borehole yields in the study area. Therefore, future groundwater resource development in the study area should be based on a proper analysis of the geological configurations of the Sokoto basin. This study provides an outlook on the groundwater potentials of the study area and aquifers that can provide a basis for sustainable groundwater development policy. Thus, the study has shown how multivariate and regression analysis can be used to study the hydrogeological conditions of a particular basin. Therefore, it is hoped that this study's findings will inspire other researchers to take a comparable approach.
... Although the close chamber technique for measuring GHGs emissions had been widely used in wetlands Wilson et al., 2016;Hernández et al., 2018;Windham-Myers et al., 2018), Camacho et al. (2017), reported that methane emission by ebullition processes cannot be accurately estimated by close chamber techniques, situation that needs to be analyzed for standard methods in future studies. Other authors (Chaichana, 2018;Wali, 2018) had compared the advantages and disadvantages in the use of close chamber and Eddy covariance techniques, indicating that selection of the best method depends on some cases in the resources available, landscape type and objectives. The possibility of using both methods for a better understanding of methane emissions is the ideal scenario, but there are not always the resources to do it. ...
Carbon balance in tropical freshwater wetlands on the coastal plain of the Gulf of Mexico Wetlands play an important role as carbon stores; however, these ecosystems also contribute to the emission of greenhouse gases (GHG). In this study, we compared the carbon balance (CB) in coastal freshwater marshes and swamps. We use three different methods, which are described in the literature. The first is based upon the CB basis (Carbon-emission subtracted to Carbon-sequestration), without considering the global warming potential (GWP) of GHG. The second method is a CB considering the GWP, and the third method estimated the wetland function as carbon sink or source, by using a dynamic model with different horizon times (20, 100 and 500 years). With the first method, the studied wetland soils functioned as carbon sinks. Using the second method, the carbon in the form of GHG was up to 5 times more than sequestered carbon, however, the methodology does not consider the dynamics of gases in the atmosphere. By using a dynamic model that integrates productivity , plant respiration, the half-life of the gases and soil carbon emitted as methane, it was found that these ecosystems are net sinks carbon at horizon times of 500 years. This outlines a need to conserve and restore wetlands, and demonstrates the wetlands role as carbon sinks without concerning that they are sources of GHGs. Balance de carbono en humedales tropicales de agua dulce de la planicie costera del Golfo de México Los humedales juegan un papel importante en como almacenadores de carbono. Sin embargo, estos ecosistemas también contribuyen a las emisiones de gases de efecto invernadero (GHG). En este estudio, se comparó el balance de carbono (CB) en humedales herbáceos y arbóreos costeros de agua dulce. Se usaron tres métodos, descritos en la literatura. El primer método de CB se basó en el carbono emitido restado a carbono almacenado, sin considerar el potencial de calentamiento global (GWP) de GHG. El Segundo método de CB consideró el GWP, y el tercer método estimó la función del humedal como sumidero o fuente de carbono, usando un modelo dinámico con diferentes horizontes de tiempo (20, 100 y 500 años). Con el primer método, el suelo de humedales estudiados funcionó como sumidero de carbono. Usando el segundo método, el carbono en forma de GHG fue hasta 5 veces mayor que el carbono almacenado; sin embargo, la metodología no considera la dinámica de gases en la atmósfera. Usando un modelo dinámico que integra productividad, respiración de las plantas, vida media de los gases en la atmósfera y carbono del suelo emitido como metano, se encontró que estos ecosistemas son sumideros netos de carbono a un horizonte de tiempo de 500 años. Lo anterior refiere a la necesidad de conservar y restaurar humedales, y demos-trar el papel de los humedales como sumideros de carbono, sin preocuparse de que estos sean fuentes de GHGs. Palabras clave: humedales arbóreos de agua dulce, humedales herbáceos, almacenamiento de carbono, emisiones de carbo-no, modelo dinámico de carbono Limnetica, 39(2): 653-665 (2020).
This review presents a detailed analysis of hydrogeological and hydrochemical conditions of the Niger Delta Basin. Hydrogeologically, the specific capacities recorded from different areas within this Basin vary from 6700 lit/hr/m to 13,500 lit/ hr/m. The water table is very close to the ground surface and varies from 0 to 4 meters. Unconfined groundwater aquifers occur in shallow unconfined aquifers, sands of the coastal beach ridges and river point bars, and sandy islands within the mangrove belt. There is a stable water table fluctuation which characterised the high precipitation zone. The shallow aquifers of Benin Formation are more porous than those in the Deltaic areas. In the southern areas, along the coastal zone, an artesian condition occurs. However, the aquifers are less transmissible with increased depth of the confined aquifer, owing to its more delicate texture. Therefore, more compact, and less permeable, or that there is not enough water in storage. More than half of groundwater sources in the Basin are acidic. Based on mean TDS concentration groundwater, fall in an excellent class for drinking. Groundwater classification based on conductivity showed all the reported findings indicate conductivity ranging from 250-750 µS/cm. Based on cation and anion chemistry, the Niger Delta Basin holds water of relatively acceptable drinking quality. However, the uncontrolled groundwater development, land-use changes, pollution from industrial, municipal, and agricultural effluents pose a threat to groundwater quality protection. Thus, a policy guideline is required to protect groundwater from pollution.
