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PHYSICS (585 journals)

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Journal Cover Physics and Chemistry of the Earth, Parts A/B/C
  [SJR: 0.611]   [H-I: 26]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1474-7065
   Published by Elsevier Homepage  [3175 journals]
  • Wetland biogeochemical processes and simulation modeling
    • Authors: Junhong Bai; Laibin Huang; Haifeng Gao; Jia Jia; Xin Wang
      Pages: 1 - 2
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Junhong Bai, Laibin Huang, Haifeng Gao, Jia Jia, Xin Wang


      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.01.005
      Issue No: Vol. 103 (2018)
       
  • Short-term effects of tidal flooding on soil nitrogen mineralization in a
           Chinese tidal salt marsh
    • Authors: Haifeng Gao; Junhong Bai; Xiaoya Deng; Qiongqiong Lu; Xiaofei Ye
      Pages: 3 - 10
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Haifeng Gao, Junhong Bai, Xiaoya Deng, Qiongqiong Lu, Xiaofei Ye
      Tidal flooding is an important control of nitrogen biogeochemistry in wetland ecosystems of Yellow River Delta, China. Variations in hydrology could change soil redox dynamics and conditions for microorganisms living. A tidal simulation experiment was designed to extract tidal flooding effect on nitrogen mineralization of salt marsh soil. Inorganic nitrogen and relevant enzyme were measured during the 20-day incubation period. Considering the variation of both inorganic N and enzymes, nitrogen mineralization process in tidal salt marsh could be divided into 2 phases of short term response and longtime adaption by around 12th incubation day as the inflection point. Soil ammonium nitrogen (NH4 +-N) and volatilized ammonia (NH3) occupied the mineralization process since nitrate nitrogen (NO3 −-N) was not detected over whole incubation period. NH4 +-N varied fluctuant and increased significantly after 12 day's incubation. Released NH3 reached to peak value of 14.24 mg m−2 d−1 at the inflection point and declined thereafter. Inorganic nitrogen released according to net nitrogen mineralization rate (RM) under the tidal flooding condition without plant uptake except first 2 days. However, during the transitional period of 6–12 days, RM decreased notably to almost 0 and increased again after inflection point with the value of 0.182 mg kg−1 d−1. It might be due to the change of microbial composition and function when soil shifted from oxic to anoxic, which were reflected by arylamidase, urease and fluorescein diacetate. Fluorescein diacetate hydrolysis and arylamidase had the similar variation of U style with decreasing activities before 12 days' incubation. All the enzymes measured in this experiment increased after inflection point. Whereas, urease activity kept constant from 2 to 12 days. Alternant oxidation reduction condition would increase N loss through denitrification and ammonia volatilization during the transitional period, while more inorganic nitrogen would be available in reductive environment of long-term tidal flooding. Therefore, hydrological process regulation has great influence on nitrogen cycling and further influence on wetland productivity.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.04.002
      Issue No: Vol. 103 (2018)
       
  • Dynamic characteristics of soil respiration in Yellow River Delta
           wetlands, China
    • Authors: Xiao Wang; Xianxiang Luo; Hongli Jia; Hao Zheng
      Pages: 11 - 18
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Xiao Wang, Xianxiang Luo, Hongli Jia, Hao Zheng
      The stable soil carbon (C) pool in coastal wetlands, referred to as “blue C”, which has been extensively damaged by climate change and soil degradation, is of importance to maintain global C cycle. Therefore, to investigate the dynamic characteristics of soil respiration rate and evaluate C budgets in coastal wetlands are urgently. In this study, the diurnal and seasonal variation of soil respiration rate in the reed wetland land (RL) and the bare wetland land (BL) was measured in situ with the dynamic gas-infrared CO2 method in four seasons, and the factors impacted on the dynamic characteristics of soil respiration were investigated. The results showed that the diurnal variation of soil respiration rate consistently presented a “U” curve pattern in April, July, and September, with the maximum values at 12:00 a.m. and the minimum values at 6:00 a.m. In the same season, the diurnal soil respiration rate in RL was significantly greater than those in BL (P < 0.05). In April, July, and September, the mean diurnal soil respiration rate was 0.14, 0.42, and 0.39 μmol m−2 s−1 in RL, 0.05, 0.22, 0.13, and 0.01 μmol m−2 s−1 in BL, respectively. Soil surface temperature was the primary factor that influenced soil respiration, which was confirmed by the exponential positive correlation between the soil respiration rate and soil surface temperature in BL and RL (P < 0.05). In addition, the high salinity of soils suppressed soil respiration, confirming by the significantly negative correlation between soil respiration rate and the content of soluble salt. These results will be useful for understanding the mechanisms underlying soil respiration and elevating C sequestration potential in the coastal wetlands.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.06.008
      Issue No: Vol. 103 (2018)
       
  • Phosphorus fraction and phosphate sorption-release characteristics of the
           wetland sediments in the Yellow River Delta
    • Authors: Yuan Cui; Rong Xiao; Ying Xie; Mingxiang Zhang
      Pages: 19 - 27
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Yuan Cui, Rong Xiao, Ying Xie, Mingxiang Zhang
      The aim of this study was to investigate phosphorus (P) fractions and phosphate sorption-release characteristics of the surface sediments regarding the wetland restoration in the Yellow River Delta (YRD). Sediments samples were collected from three typical sample plots: Phragmites australis community (p), Suaeda salsa community (s), and bare land (b) both in natural wetland (N) and restored wetland (R). The results showed that the mean content of TP was 541.58 mg/kg, and the rank order of P fractions were: inorganic phosphorus (IP) (65.6%) > residual phosphorus (RP) (24.9%) > organic phosphorus (OP) (9.5%). For sediments under the same land cover, TP and OP contents were significantly higher in natural wetlands than those in restored wetlands. This indicated that the restoration project really made a difference in TP content of sediments, and the decreased TP might result from decreased OP. For P kinetics sorption, a quick sorption mainly occurred within 0.5 h. The maximum phosphorus adsorption capacities (Q max) ranging from 139.40 mg/kg to 224.06 mg/kg and the bonding energy constant (K) ranging from 0.33 mg/L to 1.37 mg/L were both obtained using a Langmuir model. In addition, Q max, P release (P r) and P release rates (P rr) were in the order of Nb > Np > Ns > Rb > Rp > Rs, Np > Rp > Ns > Rs = Nb > Rb and Rp > Ns > Rs > Rb > Np > Nb, respectively. This indicated that sediments from natural wetland could adsorb more P as well as release more P into overlying water, moreover, more content of P were left in sediments comparing to restored wetland. Sediments from bare land were more likely to retain P as a pool because of the highest sorption capacity while lowest release potential. Our study showed that P sorption-release and the quick sorption processes were mainly affected by sediment moisture, amorphous iron and aluminum oxides (Feox and Alox). Besides, Q max was related to background value of sediments P. OP was the major P fraction adsorbed by sediments, and the P adsorbed by sediments was mainly adsorbed on Feox and Alox.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.06.005
      Issue No: Vol. 103 (2018)
       
  • Soil carbon, nitrogen, and phosphorus stoichiometry of three dominant
           plant communities distributed along a small-scale elevation gradient in
           the East Dongting Lake
    • Authors: Cong Hu; Feng Li; Yong-hong Xie; Zheng-miao Deng; Xin-sheng Chen
      Pages: 28 - 34
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Cong Hu, Feng Li, Yong-hong Xie, Zheng-miao Deng, Xin-sheng Chen
      Soil carbon (C), nitrogen (N), and phosphorus (P) stoichiometry greatly affects plant community succession and structure. However, few studies have examined the soil stoichiometric changes in different vegetation communities of freshwater wetland ecosystems along an elevation gradient distribution. In the present study, soil nutrient concentrations (C, N, and P), soil stoichiometry (C:N, C:P, and N:P ratios), and other soil physicochemical characteristics were measured and analyzed in 62 soil samples collected from three dominant plant communities (Carex brevicuspis, Artemisia selengensis, and Miscanthus sacchariflorus) in the East Dongting Lake wetlands. The concentration ranges of soil organic carbon (SOC), total soil nitrogen (TN), and total soil phosphorus (TP) were 9.42–45.97 g/kg, 1.09–5.50 g/kg, and 0.60–1.70 g/kg, respectively. SOC and TN concentrations were the highest in soil from the C. brevicuspis community (27.48 g/kg and 2.78 g/kg, respectively) and the lowest in soil from the A. selengensis community (17.97 g/kg and 1.71 g/kg, respectively). However, the highest and lowest TP concentrations were detected in soil from the A. selengensis (1.03 g/kg) and M. sacchariflorus (0.89 g/kg) communities, respectively, and the C:N ratios were the highest and lowest in soil from the M. sacchariflorus (12.72) and A. selengensis (12.01) communities, respectively. C:P and N:P ratios were the highest in soil from the C. brevicuspis community (72.77 and 6.46, respectively) and the lowest in soil from the A. selengensis community (45.52 and 3.76, respectively). Correlation analyses confirmed that SOC concentrations were positively correlated with TN and TP, and C:N and N:P ratios were positively correlated with C:P. These data indicated that soil C, N, and P stoichiometry differed significantly among different plant communities and that these differences might be accounted for by variations in the hydrological conditions of the three communities.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.04.001
      Issue No: Vol. 103 (2018)
       
  • Vertical distribution of mercury and MeHg in Nandagang and Beidagang
           wetlands: Influence of microtopography
    • Authors: Ruhai Liu; Yanyan Zhang; Yan Wang; Jin Zhao; Huayao Shan
      Pages: 45 - 50
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Ruhai Liu, Yanyan Zhang, Yan Wang, Jin Zhao, Huayao Shan
      Wetlands often show different small-scale topography, such as riffle, habitat island, deep water, shallow water zone and dry zone. Core soils in different micro topographical landforms of Nandagang and Beidagang wetlands in North China were sampled for THg and MeHg to analyze the influence of microtopography. Results showed that THg content in surface soil (<2 cm) was little higher than that at depth 2–4 cm of all stations. There were several peaks in the profile, which reflected mercury pollution in past. High THg content in undisturbed natural wetland soil implied accumulation of mercury. Harvest of plant, drained water decreased the accumulation of mercury in wetlands. Water level caused by microtopography affected the production of MeHg. Depth of the highest MeHg content decreased from N1, N2, N6, N3 to N4 following the increase of water level. Plant type and coverage also affected the vertical distribution of MeHg. More detailed profiles of MeHg, organic matter and total phosphorus in different sites show strong differences in soil chemistry, suggesting a complex interplay among hydrology, biogeochemistry and microtopography.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.04.003
      Issue No: Vol. 103 (2018)
       
  • Characterization of soil salinization in typical estuarine area of the
           Jiaozhou Bay, China
    • Authors: Qifei Li; Min Xi; Qinggai Wang; Fanlong Kong; Yue Li
      Pages: 51 - 61
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Qifei Li, Min Xi, Qinggai Wang, Fanlong Kong, Yue Li
      In this study, the characteristics of soil salinization and the effects of main land use/land cover and other factors in typical estuarine area of the Jiaozhou Bay are investigated. Soil samples were collected in the parallel coastal zone, vertical coastal zone and longitudinal profile depth in the area to determine the soil salt content. The correlation analysis and principal component analysis are used to address the general characteristics of soil salinization in the study area. In the horizontal direction, there are moderate salinization, severe salinization and saline soil state. The farther from the sea (within 1.1 km), the lower the soil salinization degree. In the direction of longitudinal profile depth, there are severe salinization and saline soil state, and the soil salt content is accumulated in the surface and bottom. The Na+ and Cl− are the dominant cation and anion, respectively, the distributions of which are consistent with that of salt content. All the salinization indexes, except for soil pH, are of moderate/strong variability. The invasion of Spartina alterniflora results in the increase of soil salt content and salinization degree, the effects of which are mainly determined by the physiological characteristics and the growth years. The degree of soil salinization increased significantly in the aquaculture ponds, which is mainly caused by the use of chemicals. The correlation between soil salt content and Na+, Cl− is particularly significant. From the results of principal component analysis, Na+, Cl−, Ca2+, Mg2+ and SO4 2− could be used as main diagnostic factors for salinization in typical estuarine area of the Jiaozhou Bay. The effects of NaCl and sulfate on salt content further affect the degree of salinization in the estuarine area.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.06.010
      Issue No: Vol. 103 (2018)
       
  • Effect of coastal eutrophication on growth and physiology of Spartina
           alterniflora Loisel
    • Authors: Yu Zhang; Baoshan Cui; Tian Xie; Qing Wang; Jiaguo Yan
      Pages: 62 - 67
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Yu Zhang, Baoshan Cui, Tian Xie, Qing Wang, Jiaguo Yan
      Coastal eutrophication has become a driver of coastal wetlands loss. Eutrophication caused by the increase of nitrogen content was one of the most main reasons. We analyzed that exogenous ammonium nitrogen (EAN) of different concentration influenced on the growth and physiology of Spartina alterniflora Loisel (S. alterniflora) through simulated conditions. The results showed that growth of the root system largely depended on the environment conditions around S. alterniflora. Higher nitrogen concentration promoted aboveground biomass and increased plant height. On the other hand, as the increase of growth period, higher nitrogen concentration could inhibit the elongation growth of root and reduce the underground biomass. We showed that activity of POD, SOD and MDA content changed in an upward trend along with the increased nitrogen level. There was a significant positive correlation between H+ flux and NO3 − flux (r = 0.601, P < 0.01), and a significant negative correlation between H+ flux and NH4 + flux (r = −0.713, P < 0.01) within 1.5 mm from the root tip of S. alterniflora. Efflux and influx of ions were associated with changes of nitrogen levels. This research will provide data supporting for coastal wetland restoration of biodiversity reduction caused by coastal eutrophication.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.01.016
      Issue No: Vol. 103 (2018)
       
  • Effects of drought and salt stresses on growth characteristics of
           euhalophyte Suaeda salsa in coastal wetlands
    • Authors: Jia Jia; Chen Huang; Junhong Bai; Guangliang Zhang; Qingqing Zhao; Xiaojun Wen
      Pages: 68 - 74
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Jia Jia, Chen Huang, Junhong Bai, Guangliang Zhang, Qingqing Zhao, Xiaojun Wen
      The pot experiment was carried out in the Yellow River Delta to investigate the effects of drought and salt stresses on growth characteristics of Suaeda salsa, and to reveal the role of nitrogen (N) application in alleviation effects of drought and salt stresses on Suaeda salsa in coastal wetlands. In this study, plants were exposed to two water contents treatments (i.e., 14% and 26% water content), four salinity treatments (i.e., 2 g/kg, 4 g/kg, 6 g/kg, and 8 g/kg NaCl) and two N application treatments (i.e., 0 and 200 N mg/kg) in field conditions. Growth characteristics of Suaeda salsa were assessed as fresh weight, dry weight, height, total nitrogen (TN) and total carbon (TC). Our results showed that fresh weight, dry weight and height of Suaeda salsa promoted at lower salinity treatments but reduced at higher salinity treatments, while TN and TC contents kept stable with increasing salinity levels. Drought stress diminished the fresh weight, dry weight and height of Suaeda salsa, whereas enhanced TN contents. Under the interactive stresses of drought and salt, fresh weight and dry weight showed slight increases at lower salinity treatments, whereas decreases at higher salinity treatments. N application promoted the fresh weight, dry weight and TN contents other than the height and TC contents of Suaeda salsa. The interaction between N application and salt stress exhibited a significant influence on the fresh weight and dry weight of Suaeda salsa, whereas no significant interaction between N application and drought stress was observed. These findings of this study suggested that higher salinity, drought and the interaction of drought and higher salinity would retard the growth of Suaeda salsa, whereas N application could only mitigate the deleterious effects of salt stress on Suaeda salsa.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.01.002
      Issue No: Vol. 103 (2018)
       
  • Effects of soil abiotic factors on the plant morphology in an intertidal
           salt marsh, Yellow River Delta, China
    • Authors: Shanze Li; Baoshan Cui; Junhong Bai; Tian Xie; Jiaguo Yan; Qing Wang; Shuyan Zhang
      Pages: 75 - 80
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Shanze Li, Baoshan Cui, Junhong Bai, Tian Xie, Jiaguo Yan, Qing Wang, Shuyan Zhang
      Plant morphology plays important role in studying biogeography in many ecosystems. Suadea salsa, as a native plant community of northern China and an important habitat for diversity of waterbirds and macrobenthos, has often been overlooked. Nowadays, S. salsa community is facing great loss due to coastal reclamation activities and natural disturbances. To maintain and restore S. salsa community, it's important to address the plant morphology across marsh zones, as well as its relationships with local soil abiotic conditions. In our studied intertidal salt marsh, we found that less flood disturbance frequency, softer soil conditions, rich soil organic matter, total carbon and total nitrogen, lower water depth and water content, less species competition will benefit S. salsa plant in the morphology of high coverage, above-ground biomass, shoot height and leaf length. Lower soil porewater salinity will benefit the below-ground biomass of S. salsa. Thus, we recommend managers help alleviate soil abiotic stresses in the intertidal salt marshes, making the soil conditions more suitable for S. salsa growth and succession.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.04.004
      Issue No: Vol. 103 (2018)
       
  • Rethinking the role of edaphic condition in halophyte vegetation
           degradation on salt marshes due to coastal defense structure
    • Authors: Tian Xie; Baoshan Cui; Junhong Bai; Shanze Li; Shuyan Zhang
      Pages: 81 - 90
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Tian Xie, Baoshan Cui, Junhong Bai, Shanze Li, Shuyan Zhang
      Determining how human disturbance affects plant community persistence and species conservation is one of the most pressing ecological challenges. The large-scale disturbance form defense structures usually have a long-term and potential effect on phytocommunity in coastal saltmarshes. Coastal defense structures usually remove the effect of tidal wave on tidal salt marshes. As a consequence, edaphic factors such as the salinity and moisture contents are disturbed by tidal action blocking. However, few previous studies have explicitly addressed the response of halophyte species persistence and dynamics to the changing edaphic conditions. The understanding of the response of species composition in seed banks and aboveground vegetation to the stress is important to identify ecological effect of coastal defense structures and provide usefully insight into restoration. Here, we conducted a field study to distinguish the density, species composition and relationships of seed bank with aboveground vegetation between tidal flat wetlands with and without coastal defense structures. We also addressed the role of edaphic condition in vegetation degradation caused by coastal defense structures in combination with field monitor and greenhouse experiments. Our results showed the density of the seed bank and aboveground vegetation in the tidal flat without coastal defense structures was significantly lower than the surrounded flat with coastal defense structures. A total of 14 species were founded in the surrounded flat seed bank and 11 species in the tidal flat, but three species were only recorded in aboveground vegetation of the tidal flat which was much lower than 24 aboveground species in the surrounded flat. The absent of species in aboveground vegetation contributed to low germination rate which depend on the edaphic condition. The germination of seeds in the seed bank were inhabited by high soil salinity in the tidal flat and low soil moisture in the surrounded flat. Our study supported the hypothesis that the change of edaphic condition caused by coastal defense structures was the main reason for the difference of the species composition similarity between aboveground vegetation and the soil seed bank between the tidal and surrounded flats. Therefore, mitigating the hydrological disturbance and maintaining the original state of edaphic factors would be useful implications for reducing the ecological effect of defense structure to vegetation communities in coastal salt marshes.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2016.12.001
      Issue No: Vol. 103 (2018)
       
  • Simulation of the effect of an oil refining project on the water
           environment using the MIKE 21 model
    • Authors: Peng Jia; Qinggai Wang; Xuchuan Lu; Beibei Zhang; Chen Li; Sa Li; Shibei Li; Yaping Wang
      Pages: 91 - 100
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Peng Jia, Qinggai Wang, Xuchuan Lu, Beibei Zhang, Chen Li, Sa Li, Shibei Li, Yaping Wang
      A case study of the Caofeidian oil refining project is conducted. A two-dimensional convective dispersion mathematical model is established to simulate the increase in the concentration of pollutants resulting from the wastewater discharge from the Caofeidian oil refining project and to analyze the characteristics of the dispersion of pollutants after wastewater is discharged and the effect of the wastewater discharge on the surrounding sea areas. The results demonstrate the following: (1) The Caofeidian sea area has strong tidal currents, which are significantly affected by the terrain. There are significant differences in the tidal current velocity and the direction between the deep-water areas and the shoals. The direction of the tidal currents in the deep-water areas is essentially parallel to the contour lines of the sea areas. Onshore currents and rip currents submerging the shoals are the dominant currents in the shoals. (2) The pollutant concentration field in the offshore areas changes periodically with the movement of the tidal current. The dilution and dispersion of pollutants are affected by the ocean currents in different tidal periods. The turbulent dispersion of pollutants is the most intense when a neap tide ebbs, followed by when a neap tide rises, when a spring tide ebbs and when a spring tide rises. (3) There are relatively good hydrodynamic conditions near the project's wastewater discharge outlet. Wastewater is well diluted after being discharged. Areas with high concentrations of pollutants are concentrated near the wastewater discharge outlet and the offshore areas. These pollutants migrate southwestward with the flood tidal current and northeastward with the ebb tidal current and have no significant impact on the protection targets in the open sea areas and nearby sea areas.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.02.003
      Issue No: Vol. 103 (2018)
       
  • Impact assessments of water allocation on water environment of river
           network: Method and application
    • Authors: Qinggai Wang; Yaping Wang; Xuchuan Lu; Peng Jia; Beibei Zhang; Chen Li; Sa Li; Shibei Li
      Pages: 101 - 106
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Qinggai Wang, Yaping Wang, Xuchuan Lu, Peng Jia, Beibei Zhang, Chen Li, Sa Li, Shibei Li
      Two types of water allocation scenarios were proposed for reasonably utilizing water resources and improving water quality in a two-river network in Tongzhou District. Water circulation and quality were selected as two important indexes to evaluate the two scenario. Meanwhile, one-dimensional water amount and quality model was set up on the basis of the MIKE11 model to compare the two scenarios in terms of improving water environment. The results showed that both scenarios changed the hydrodynamic conditions, and consequently the river flow reached 0.05 m/s or higher in the central part of river stream. In addition, we also found that the two plans have similar effects on water quality, with first scenario producing larger area of water class III and IV than the second scenario.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.01.014
      Issue No: Vol. 103 (2018)
       
  • Understanding land use change impacts on microclimate using Weather
           Research and Forecasting (WRF) model
    • Authors: Xia Li; Chandana Mitra; Li Dong; Qichun Yang
      Pages: 115 - 126
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Xia Li, Chandana Mitra, Li Dong, Qichun Yang
      To explore potential climatic consequences of land cover change in the Kolkata Metropolitan Development area, we projected microclimate conditions in this area using the Weather Research and Forecasting (WRF) model driven by future land use scenarios. Specifically, we considered two land conversion scenarios including an urbanization scenario that all the wetlands and croplands would be converted to built-up areas, and an irrigation expansion scenario in which all wetlands and dry croplands would be replaced by irrigated croplands. Results indicated that land use and land cover (LULC) change would dramatically increase regional temperature in this area under the urbanization scenario, but expanded irrigation tended to have a cooling effect. In the urbanization scenario, precipitation center tended to move eastward and lead to increased rainfall in eastern parts of this region. Increased irrigation stimulated rainfall in central and eastern areas but reduced rainfall in southwestern and northwestern parts of the study area. This study also demonstrated that urbanization significantly reduced latent heat fluxes and albedo of land surface; while increased sensible heat flux changes following urbanization suggested that developed land surfaces mainly acted as heat sources. In this study, climate change projection not only predicts future spatiotemporal patterns of multiple climate factors, but also provides valuable insights into policy making related to land use management, water resource management, and agriculture management to adapt and mitigate future climate changes in this populous region.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.01.017
      Issue No: Vol. 103 (2018)
       
  • Non-flood season neap tides in the Yangtze estuary offshore: Flow mixing
           processes and its potential impacts on adjacent wetlands
    • Authors: Taoyuan Wei; Zhanghua Wang; Jing Chen; Maotian Li
      Pages: 127 - 139
      Abstract: Publication date: February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 103
      Author(s): Taoyuan Wei, Zhanghua Wang, Jing Chen, Maotian Li
      How flow mixing process influences the wetlands of the Yangtze Estuary is still poorly understood. Hydrological fieldwork was conducted on five vessel-anchored sites (S1-S2; M1-M2-M3) near the major wetlands of the Yangtze Estuary offshore (121°57′-122°30′E, 30°50′-31°23′N) on May 8-11 2004, to examine the dynamics of neap tides in the non-flood season of the Yangtze (∼24, 700 m3s-1 at Datong) and their impacts on adjacent wetlands. Based on the measurement of the acoustic Doppler current profiler (aDcp), direct-reading current meter and optical backscattering sensor (OBS-3A), two flow patterns were revealed: 1) well mixing flow pattern caused by the turbulent tidal currents, and 2) weak mixing flow pattern resulted by the estuarine circulation in the North Port of the estuary. The characteristics of such different flow patterns were analyzed and resultant sediment dispersals were discussed in relation to the adjacent wetlands. It is suggested that the estuarine circulation might be the important process to nourish the eastern wetland of the Yangtze Estuary which has been neglected before.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2017.06.004
      Issue No: Vol. 103 (2018)
       
  • Heavy metal contents and transfer capacities of Phragmites australis and
           Suaeda salsa in the Yellow River Delta, China
    • Authors: Shuai Zhang; Junhong Bai; Wei Wang; Laibing Huang; Guangliang Zhang; Dawei Wang
      Abstract: Publication date: Available online 16 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Shuai Zhang, Junhong Bai, Wei Wang, Laibing Huang, Guangliang Zhang, Dawei Wang
      Plant samples including roots, stems and leaves of Phragmites australis and Suaeda salsa were collected in the short-term-flooding and tidal-flooding wetlands of the Yellow River Delta of China. Six heavy metals (e.g., As, Cd, Cr, Cu, Pb, and Zn) were measured in roots, stems and leaves of each plant species using inductively coupled plasma atomic absorption spectrometry (ICP-AAS) to investigate the levels, and transfer capabilities of heavy metals in these two plant species. Our results showed that in tidal flooding wetlands, the contents of As, Cr and Cd in roots of Phragmites australis and Suaeda salsa were higher than those in their stems and leaves. Suaeda salsa showed higher contents of Pb and Zn in leaves than those in roots and stems, whereas lower levels of Pb and Zn were observed in Phragmites australis. In the short-term-flooding wetlands, heavy metal contents exhibited a big difference between different tissues of Phragmites australis and Suaeda salsa, and both plant species showed higher levels of Pb and Zn in leaves. Suaeda salsa roots enriched more As and Cd, whereas higher enrichment levels were observed in Phragmites australis leaves, which indicated different transfer capacities of these two wetland plants. The transfer factors for stems and leaves of Phragmites australis in tidal flooding wetlands significantly differed from those in short-term flooding wetlands, however, no significant differences in transfer factors for stems and leaves of Suaeda salsa were observed between these two types of wetlands.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.011
       
  • Influence of urbanization-driven land use/cover change on climate: The
           case of Addis Ababa, Ethiopia
    • Authors: Bisrat Kifle Arsiso; Gizaw Mengistu Tsidu; Gerrit Hendrik Stoffberg; Tsegaye Tadesse
      Abstract: Publication date: Available online 13 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Bisrat Kifle Arsiso, Gizaw Mengistu Tsidu, Gerrit Hendrik Stoffberg, Tsegaye Tadesse
      Land use change is the second most important anthropogenic influence on climate beside the emission of greenhouse gases. Urbanization is leading to significant land use changes in Africa since the continent is undergoing rapid urbanization and population growth in recent decades. Addis Ababa is one of these fast growing cities in the continent. Therefore, detection of land use change is very important to identify its impact on climate and sustainable land use management of the city. The study used Landsat images to generate land use/land cover change map for the city. The normalized difference vegetation index (NDVI) is used to detect the major changes of vegetation cover occurred between 1986 and 2011 as a result of land use and land cover change. Downscaled HadCM3 simulations under A2 and B2 emission scenarios is used to investigate future urban heat island (UHI) over the city of Addis Ababa. In the city, the analysis of Landsat images has shown that the built-up areas have increased by 121.88 km2 within the last 25 years. This finding is consistent with NDVI images taken over the same period that reveal a decline in vegetation cover. The impact of the urbanization-driven land use/cover change has resulted in notable nocturnal urban heat island (UHI) as revealed from an average increase in minimum temperature of 1.5 ° C  at the centre of the city relative to rural site over the 1960–2001 period. The mean of the 2006–2010 spatial minimum temperature anomaly with respect to the base period mean of 1981–2005 is consistent with the observed UHI. The temperature in the central areas (both commercial and residential sectors) of Addis Ababa is warmer than the surrounding areas. The thermal gradient increase from about 1.44 ° C  at the centre (Arada, Addis Ketema, Lideta and Kirkos) to 0.21 ° C  at the peripheral parts of the city (Gulele, Bole, Nefasilk-Lafto, Kolfe Keranio and east of Yeka sub-cities) transecting across the hot (high-density urban) to moderately warm to cool (non-built-up) areas. However, the maximum temperature and rainfall exhibit variability that follows topographic differences. Future urban climate change projections of urban heat island formation under A2 and B2 emission scenarios show that the nocturnal UHI will be intense in winter or dry season episodes in the city. The highest urban warming is from October to December (2.5 ° C to 3.2 ° C ) during 2050s and 2080s.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.009
       
  • Validation of satellite-based rainfall in Kalahari
    • Authors: Moiteela Lekula; Maciek W. Lubczynski; Elisha M. Shemang; Wouter Verhoef
      Abstract: Publication date: Available online 9 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Moiteela Lekula, Maciek W. Lubczynski, Elisha M. Shemang, Wouter Verhoef
      Water resources management in arid and semi-arid areas is hampered by insufficient rainfall data, typically obtained from sparsely distributed rain gauges. Satellite-based rainfall estimates (SREs) are alternative sources of such data in these areas. In this study, daily rainfall estimates from FEWS-RFE∼11 km, TRMM-3B42∼27 km, CMOPRH∼27 km and CMORPH∼8 km were evaluated against nine, daily rain gauge records in Central Kalahari Basin (CKB), over a five-year period, 01/01/2001-31/12/2005. The aims were to evaluate the daily rainfall detection capabilities of the four SRE algorithms, analyze the spatio-temporal variability of rainfall in the CKB and perform bias-correction of the four SREs. Evaluation methods included scatter plot analysis, descriptive statistics, categorical statistics and bias decomposition. The spatio-temporal variability of rainfall, was assessed using the SREs' mean annual rainfall, standard deviation, coefficient of variation and spatial correlation functions. Bias correction of the four SREs was conducted using a Time-Varying Space-Fixed bias-correction scheme. The results underlined the importance of validating daily SREs, as they had different rainfall detection capabilities in the CKB. The FEWS-RFE∼11 km performed best, providing better results of descriptive and categorical statistics than the other three SREs, although bias decomposition showed that all SREs underestimated rainfall. The analysis showed that the most reliable SREs performance analysis indicator were the frequency of “miss” rainfall events and the “miss-bias”, as they directly indicated SREs' sensitivity and bias of rainfall detection, respectively. The Time Varying and Space Fixed (TVSF) bias-correction scheme, improved some error measures but resulted in the reduction of the spatial correlation distance, thus increased, already high, spatial rainfall variability of all the four SREs. This study highlighted SREs as valuable source of daily rainfall data providing good spatio-temporal data coverage especially suitable for areas with limited rain gauges, such as the CKB, but also emphasized SREs' drawbacks, creating avenue for follow up research.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.010
       
  • Flood hazard vulnerability assessment in Kashmir Valley, India using
           geospatial approach
    • Authors: Tauseef Ahmad; Arvind Chandra Pandey; Amit Kumar
      Abstract: Publication date: Available online 9 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Tauseef Ahmad, Arvind Chandra Pandey, Amit Kumar


      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.003
       
  • Urban flood simulation and prioritization of critical urban sub-catchments
           using SWMM model and PROMETHEE II approach
    • Authors: Sahar Babaei; Reza Ghazavi; Mahdi Erfanian
      Abstract: Publication date: Available online 9 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Sahar Babaei, Reza Ghazavi, Mahdi Erfanian
      Urban runoff increased due to augment of impervious surfaces. In order to flood mitigation during rainy season, determination of critical urban sub-catchments is very important for urban planners. Due to lack of information, adopting a simulation approach is one of the practical ways to identify the surcharged junctions and critical sub-catchments. Occurrence of destructive floods in the rainy seasons indicates the inappropriateness of the urban drainage system in Urmia. The main aims of this study were to estimate the surface runoff of urban sub-catchments using SWMM, to evaluate the accuracy of the drainage system of the study urban area and to prioritize sub-catchments using PROMETHEE II approach and SWMM. In the present study, the occurrence of rainfall event of the Urmia city (West Azerbaijan province, Iran) used for estimation of runoff depth. The study area was divided into 22 sub-catchments. For calibration and validation of model parameters, 3 rainfall events and their related runoff were measured. According to sensitivity analysis CN was the most sensitive parameter for model calibration. Amount of surcharged conduits and junctions indicates that the drainage system of the study area has not enough capacity for converting of the runoff and. For 10 year return period, depth of channels should increase by 20% for prevention of flooding in these sub-catchments. Sub-catchments were prioritized using PROMETHEE II approach and its results were compared with SWMM simulation outcomes. Based on SWMM simulation, S11, S7, S18, S16 and S1 sub-catchments are more critical sub-catchments respectively, while according to PROMETHEE method, S1, S11, S16, S14 and S18 are determined as the critical areas.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.002
       
  • Quantification of water resources uncertainties in the Luvuvhu sub-basin
           of the Limpopo river basin
    • Authors: N. Oosthuizen; D. Hughes; E. Kapangaziwiri; J. Mwenge Kahinda; V. Mvandaba
      Abstract: Publication date: Available online 9 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): N. Oosthuizen, D. Hughes, E. Kapangaziwiri, J. Mwenge Kahinda, V. Mvandaba
      In the absence of historical observed data, models are generally used to describe the different hydrological processes and generate data and information that will inform management and policy decision making. Ideally, any hydrological model should be based on a sound conceptual understanding of the processes in the basin and be backed by quantitative information for the parameterization of the model. However, these data are often inadequate in many sub-basins, necessitating the incorporation of the uncertainty related to the estimation process. This paper reports on the impact of the uncertainty related to the parameterization of the Pitman monthly model and water use data on the estimates of the water resources of the Luvuvhu, a sub-basin of the Limpopo river basin. The study reviews existing information sources associated with the quantification of water balance components and gives an update of water resources of the sub-basin. The flows generated by the model at the outlet of the basin were between 44.03 Mm3 and 45.48 Mm3 per month when incorporating +\-20% uncertainty to the main physical runoff generating parameters. The total predictive uncertainty of the model increased when water use data such as small farm and large reservoirs and irrigation were included. The dam capacity data was considered at an average of 62% uncertainty mainly as a result of the large differences between the available information in the national water resources database and that digitised from satellite imagery. Water used by irrigated crops was estimated with an average of about 50% uncertainty. The mean simulated monthly flows were between 38.57 Mm3 and 54.83 Mm3 after the water use uncertainty was added. However, it is expected that the uncertainty could be reduced by using higher resolution remote sensing imagery.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.008
       
  • Changes in streamflow contributions with increasing spatial scale in
           Thukela basin, South Africa
    • Authors: Macdex Mutema; Vincent Chaplot
      Abstract: Publication date: Available online 9 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Macdex Mutema, Vincent Chaplot
      Sustainable management of river basins requires precise understanding of the origin and variability of water fluxes. Water samples were collected in Thukela Basin (30,000 km2), South Africa, over the 2012 rainy season, from fifteen 1 m2 runoff microplots (for OF), a 5-m deep piezometer (SW) and 20-m deep borehole (GW), in the basin headwater and nested catchment outlets (microcatchment, 0.23 km2; subcatchment, 1.20 km2; catchment, 9.75 km2; sub-basin, 253 km2). The water samples were analysed for Sodium (Na) and Silica (Si) concentrations using an inductively coupled-plasma emission spectrophotometry. End Member Mixing Analysis (EMMA), with Na and Si as tracers, was then used to quantify the water compartment contributions to river flow. The results showed a general decrease of unit-area runoff in downslope direction from 5.7 to 1.2 L m−2 day−1 at microplot and microcatchment level, respectively, to 1.4 L m−2 day−1 at the basin outlet. OF contributions averaged 61% at microcatchment, 79% at subcatchment, 40% at catchment, 78% at sub-basin and 67% at the basin outlet, which corresponded to 0.82, 0.26, 5 × 10−5, 2 × 10−3 and 9 × 10−5 L m−2 day−1, respectively. The respective SW contributions were 39% (0.38 L m−2 day−1), 18% (0.10 L m−2 day−1), 49% (5 × 10−5 L m−2 day−1), 15% (4 × 10−4 L m−2 day−1) and 33% (5 × 10−5 L m−2 day−1). GW contributions were much lower at all spatial scales, but showed a general increase with increasing contributing surface area from microcatchment to sub-basin outlet followed by a decrease to the basin outlet. The end-member contributions showed large spatial variations, hence longer-term research integrating more observation points is recommended to generate adequate data for development of prediction models for this important river basin. More research linking carbon, nutrient and pollutant fluxes to water dynamics is also recommended.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.007
       
  • Preparation and application of a tyre-based activated carbon solid phase
           extraction of heavy metals in wastewater samples
    • Authors: K. Mogolodi Dimpe; J.C. Ngila; Philiswa N. Nomngongo
      Abstract: Publication date: Available online 9 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): K. Mogolodi Dimpe, J.C. Ngila, Philiswa N. Nomngongo
      In this paper, the tyre-based activated carbon solid phase extraction (SPE) method was successfully developed for simultaneous preconcentration of metal ions in the model and real water samples before their determination using flame atomic absorption spectrometry (FAAS). The activation of carbon was achieved by chemical activation and the tyre-based activated carbon was used as a sorbent for solid phase extraction. The prepared activated carbon was characterized using the scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), and Fourier Transform Infrared spectroscopy. Moreover, optimization of the proposed method was performed by the two-level full factorial design (FFD). The FFD was chosen in order to fully investigate the effect of the experimental variables (pH, eluent concentration and sample flow rate) that significantly influence the preconcentration procedure. In this model, individual factors are considered along with their interactions. In addition, modelling of the experiments allowed simultaneous variation of all experimental factors investigated, reduced the required time and number of experimental runs which consequently led to the reduction of the overall required costs. Under optimized conditions, the limits of detection and quantification (LOD and LOQ) ranged 0.66–2.12 μg L−1and 1.78–5.34 μg L−1, respectively and the enrichment factor of 25 was obtained. The developed SPE/FAAS method was validated using CWW-TM-A and CWW-TM-B wastewater standard reference materials (SRMs). The procedure showed to be accurate with satisfactory recoveries ranging from 92 to 99%. The precision (repeatability) was lower than 4% in terms of the relative standard deviation (%RSD). The developed method proved to have the capability to be used in routine analysis of heavy metals in domestic and industrial wastewater samples. In addition, the developed method can be used as a final step (before being discharged to the rivers) in wastewater treatment process in order to keep our water bodies free from toxic metals.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.005
       
  • Sanitation and hygiene practices among primary school learners in
           Ngamiland district, Botswana
    • Authors: Olekae T. Thakadu; Barbara N. Ngwenya; Nthabiseng A. Phaladze; Benjamin Bolaane
      Abstract: Publication date: Available online 9 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Olekae T. Thakadu, Barbara N. Ngwenya, Nthabiseng A. Phaladze, Benjamin Bolaane
      Improved sanitation and personal hygienic practices are considered important towards reducing the risks of spreading communicable diseases and improving public health. Diarrheal related deaths amongst adolescents are reported to be amongst the top ten for the age groups 10–19 year olds and second among the age group 10–14 year olds globally. Primary school learners in developing countries are among the most vulnerable sub-population. These mortalities and illnesses can be reduced by addressing personal hygiene among school children and simultaneously promoting better school attendance and improved learning. In order to facilitate improved health and educational outcomes, it is necessary therefore to effectively address water, sanitation and hygiene matters within the school environment. This study explored hygiene education, personal hygiene practices among learners, environmental sanitation and hygiene within three primary schools in the Ngamiland district, Botswana. From the three schools, a total sample of 285 pupils was selected using proportionate stratified random sampling technique, and 15 teachers purposively selected as key informants. Data was collected using semi-structured questionnaires with key informants and social survey instrument for learners. Results show that very few learners linked poor hygiene to the following diseases; diarrhea/upset stomach (31.7%); malaria (23%); bilharzia (16.4%), and cholera (14.8%), demonstrating low hygiene knowledge. Hygiene education in schools is infused in the curriculum, and teacher training on hygiene education is only through in-service training workshops. Regarding personal hygiene practices, over 70% of the learners indicated that they ‘always’ wash their hands before and after eating, with slightly over one-fifth indicating ‘sometimes’. Overwhelming majority of learners dispose solid waste in dustbins (99.3%, n = 284), use refuse bags (80.8%, n = 231), open skips (64%, n = 183) and very few throw trash anywhere either on the school compound or classroom (9.1%, n = 26 and 8.7%, n = 25 respectively). The current low levels of hygiene knowledge among learners in the study area has potential to affect learners' performance at school as risky hygiene practices make them vulnerable to contracting infectious diseases and missing school. This prompts the need to think beyond the infusion approach used in schools. Extra-curricular clubs in schools should be established to promote pro-hygiene behaviors and to facilitate adolescence meaningful and sustained participation.

      PubDate: 2018-02-26T15:49:38Z
      DOI: 10.1016/j.pce.2018.02.006
       
  • A geomorphological characterisation of river systems in South Africa: A
           case study of the Sabie River
    • Authors: Peter N. Eze; Jasper Knight
      Abstract: Publication date: Available online 2 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Peter N. Eze, Jasper Knight
      Fluvial geomorphology affects river character, behaviour, evolution, trajectory of change and recovery potential, and as such affects biophysical interactions within a catchment. Water bodies in South Africa, in common with many other water-stressed parts of the world, are generally under threat due to increasing natural and anthropogenic influences including aridity, siltation and pollution, as well as climate and environmental change. This study reports on a case study to characterise the geomorphology of different river systems in South Africa, with the aim of better understanding their properties, controls, and implications for biophysical interactions including water quality, biodiversity (aquatic and riparian), and human activity within the catchment. The approach adopted is based on the River Styles® framework (RSF), a geomorphology-based approach developed for rivers in New Zealand and Australia, but applied here for the first time to South Africa. Based on analysis of remote sensing imagery, SRTM-2 digital topographic data and field observations on sites through the entire river system, six geomorphic elements were identified along the Sabie River, northeast South Africa (gorge, bedrock-forced meander, low-moderate sinuosity planform controlled sand bed, meandering sand bed, low sinuosity fine grained sand bed, and floodouts), using the RSF classification scheme and based on the RSF procedural tree of Brierley and Fryirs (2005). Previous geomorphological studies along the Sabie River have shown that different reaches respond differently to episodic floods; we use these data to link river geomorphological character (as defined by the RSF) to the hydrodynamic conditions and processes giving rise to such character. This RSF approach can be used to develop a new management approach for river systems that considers their functional biophysical behaviour within individual reaches, rather than considering them as homogeneous and uniform systems.

      PubDate: 2018-02-05T13:12:57Z
      DOI: 10.1016/j.pce.2018.01.001
       
  • Integrating environmental variables and geospatial technologies in
           landscape scale habitat modelling of edible stink bugs in Zimbabwe
    • Authors: Mhosisi Masocha; Timothy Dube; Tendai Maziva
      Abstract: Publication date: Available online 2 February 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Mhosisi Masocha, Timothy Dube, Tendai Maziva
      Encosternum delegorguei spinola (edible stink bugs) is renowned for its high protein and contribution to the local economies of the people in Africa. Although many studies have evaluated the economic and nutritional importance of E. delegorguei, little is known about its geographic distribution and habitat yet the insects are an important source of protein and money for many people in Southern Africa. In this study maximum entropy model was used to predict the probability of presence of E. delegorguei in southern Zimbabwe. The environmental factors governing its geographic distribution in Zimbabwe were also evaluated. Presence/absence data were selected along thirty-five randomly selected transects. The climatic and topographic variables used to predict the distribution of E. delegorguei were: maximum temperature of the warmest month; minimum temperature of the coldest month; the normalised difference vegetation index (NDVI); altitude; slope; and aspect. It was found that E. delegorguei is most likely to occur on steep slopes with high NDVI located at an altitude ranging of 856 and 1450 m above sea level. These suitable habitats are characterised by mild temperatures ranging from 17 °C to 28 °C. These results are in agreement with previous studies indicating that E. delegorguei is sensitive to temperature, as well as tree cover and may contribute towards conserving its habitat, which is being fragmented by anthropogenic disturbance.

      PubDate: 2018-02-05T13:12:57Z
      DOI: 10.1016/j.pce.2018.01.002
       
  • Trace element geochemistry and mineralogy of coal from Samaleswari open
           cast coal block (S-OCB), Eastern India
    • Authors: Debasree Saha; Debashis Chatterjee; Sanchita Chakravarty; Madhurina Mazumder
      Abstract: Publication date: Available online 31 January 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Debasree Saha, Debashis Chatterjee, Sanchita Chakravarty, Madhurina Mazumder
      Coal samples of Samaleswari open cast coal block (S-OCB) are high ash (Aad, mean value 35.43%) and low sulphur content (St, on dry basis, mean value 0.91% < 1%) in quality. The stratigraphic variation of volatile matter and fixed carbon (dry ash-free) reflect a progress of coal metamorphism with depth that accordance to the coal rank variation from lignite to high volatile bituminous in the studied borehole. The younger coal seams have greater detrital minerals (quartz, illite, rutile) influence whereas older coal seams have greater authigenic mineral (kaolinite, dolomite, siderite, apatite) contribution that are possibly due to subsidence and sediment transportation. In S-OCB coal trace elements affinities in-between mineral and organic fraction are identified with statistical hierarchical cluster analysis. The work is further supported by the use of chemical fractionation experiment that reveals the multi mode of occurrence of several environmentally concern and interested trace elements (Sb, As, Be, Cd, Cr, Co, Cu, Pb, Mn, Ni, Zn). Among the analysed trace elements Co, Mn and Zn have major silicate association along with significant carbonate/oxide/monosulfide association. Whereas As, Cd, Cu, Pb and Ni have dominant pyritic association with notable silicate and carbonate/oxide/monosulfide association. The rest three elements (Sb, Be, Cr) have principally organic association with minor silicate and carbonate/oxide/monosulfide association. The stratigraphic variation of organo-mineral matrix content and detrital-authigenic mineral ratio are primarily related to coal rank. Geochemical character of coal also reflects a light towards proper utilisation of S-OCB coal from technical and environmental view point.

      PubDate: 2018-02-05T13:12:57Z
      DOI: 10.1016/j.pce.2018.01.004
       
  • Fertility status of cultivated floodplain soils in the Zambezi Valley,
           northern Zimbabwe
    • Authors: M. Chimweta; I.W. Nyakudya; L. Jimu
      Abstract: Publication date: Available online 2 January 2018
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): M. Chimweta, I.W. Nyakudya, L. Jimu
      Flood–recession cropping improves smallholder farmers' household food security. The objective of this study was to determine the fertility status of cultivated Zambezi Valley floodplain soils, in northern Zimbabwe. The study was conducted at three sites, along tributaries of Musengezi River. Soil samples were taken at 0.20 m depth increments to 0.60 m from hydromorphologically stratified fields, during the cropping season. Sampling points were replicated twice in each stratum at points equidistant from river edges. Relative elevations of sampling points were measured using levelling equipment. Soil was analysed using: core method for bulk density, hydrometer method for texture, loss on ignition for soil organic carbon (SOC), Kjeldahl procedure for total nitrogen (N), 0.01 M CaCl2 for pH, and Inductively Coupled Plasma (ICP) for Mehlich 3 extractable elements. Data from soil analyses were subjected to One Way Analysis of Variance and Pearson's correlation analysis. Bulk density ranged from 1.2 to 1.4 g cm−3 and it was negatively related to distance from river; and positively related to elevation at two sites. Highest values for SOC and total N were 2.04% and 0.36% respectively. Soil pH ranged from 7.70 to 8.60. Soil organic carbon and N were positively related to distance from river but negatively related to elevation. Threshold concentrations for deficiency: < 12 ppm for K, and <39 ppm for Mg, were exceeded. Calcium, Na, and micronutrients in most cases exceeded concentrations reported for floodplains. Practices that slow down flowing water and fertilizer microdosing are among possible fertility management options.

      PubDate: 2018-02-05T13:12:57Z
      DOI: 10.1016/j.pce.2017.12.005
       
  • Scenario planning for water resource management in semi arid zone
    • Authors: Rajiv Gupta; Gaurav Kumar
      Abstract: Publication date: Available online 30 December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Rajiv Gupta, Gaurav Kumar
      Scenario planning for water resource management in semi arid zone is performed using systems Input-Output approach of time domain analysis. This approach derived the future weights of input variables of the hydrological system from their precedent weights. Input variables considered here are precipitation, evaporation, population and crop irrigation. Ingles & De Souza's method and Thornthwaite model have been used to estimate runoff and evaporation respectively. Difference between precipitation inflow and the sum of runoff and evaporation has been approximated as groundwater recharge. Population and crop irrigation derived the total water demand. Compensation of total water demand by groundwater recharge has been analyzed. Further compensation has been evaluated by proposing efficient methods of water conservation. The best measure to be adopted for water conservation is suggested based on the cost benefit analysis. A case study for nine villages in Chirawa region of district Jhunjhunu, Rajasthan (India) validates the model.

      PubDate: 2018-02-05T13:12:57Z
      DOI: 10.1016/j.pce.2017.12.004
       
  • Perceptions on the use of bottled water in restaurants in Harare's Central
           Business District (CBD)
    • Authors: Olivia Sakhile Juba; Vincent Itai Tanyanyiwa
      Abstract: Publication date: Available online 27 December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Olivia Sakhile Juba, Vincent Itai Tanyanyiwa
      Bottled water use continues to expand worldwide and in the last two decades, a significant number of consumers have shifted from tap water to bottled water due to Cryptosporidium outbreaks. Bottled water consumption has increased in Harare due to erratic tap water supplies. Since 2011, forty bottled water brands have been banned because of failure to meet safety and quality standards due to contamination, unsuitable packaging, and wrong labelling. Nevertheless, the bottled water industry continues to thrive as local authorities fail to adequately purify municipal water. The study assessed the perceptions on drinking bottled water in restaurants within Harare's CBD. Demographic and social factors associated with bottled water users were established and the role and influence of stakeholders in bottling and distribution of water documented. A field survey through the administration of questionnaires to fifty restaurant users was carried out to assess the perceptions of people on the use of bottled water in terms of its safety and potential health benefits. Key informant interviews were conducted using a semi-structured interview with ten local water bottling companies as well as representatives from the Environmental Management Agency (EMA) and Standards Association of Zimbabwe (SAZ). Data were analysed using descriptive statistics and logistic regression analysis. Standard descriptive statistics were generated, with 95% confidence intervals (95% CIs). Consumers used bottled water as their primary drinking water source when they perceived that tap water was not safe. Perceptions of purity of water, bottled water convenience, and tap water unavailability seemed to determine consumption patterns among users. Females in the 18–48 age groups were more likely to think that bottled water was cleaner, safer, tasted better and was more convenient than tap water. Consumers regularly purchased bottled water for drinking and used bottled water as their primary drinking water source regardless of cost implications. Government and local authorities need to ensure that pure and clean water is availed in Harare. In addition, the public must be engaged in recognizing the relationships that exist between water quality and the capacity of local authorities to maintain taste and safety standards.

      PubDate: 2018-02-05T13:12:57Z
      DOI: 10.1016/j.pce.2017.12.003
       
  • Changes in ecosystem services associated with planting structures of
           cropland: A case study in Minle County in China
    • Authors: Yaqun Liu; Wei Song; Fengyun Mu
      Pages: 10 - 20
      Abstract: Publication date: December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 102
      Author(s): Yaqun Liu, Wei Song, Fengyun Mu
      The cropland ecosystem provides essential direct and indirect products and services to mankind such as food, fiber, biodiversity and soil conservation. A change of crop planting structure can change the ecosystem services of cropland by affecting land use type. In recent years, under the influence of regional comparative advantage and consumer demand changes, the crop planting structure in China has changed rapidly. However, there is still a lack of deep understanding on the effect of such a change in planting structure on the ecosystem services of cropland. Therefore, this research selected Minle County in the Heihe River Basin, which has small scattered croplands and a complex planting structure, as a study area. Based on the key time phase and optimal threshold of the normalized difference vegetation index (NDVI) data of the Thematic Mapper and Enhanced Thematic Mapper Plus (TM/ETM+) images, this study used the decision tree algorithm to classify and extract the crop planting structure in Minle County in 2007 and 2012 and to analyze the changes in its temporal and spatial patterns. Then, the market value method was adopted to estimate the effect of the change in crop planting structure on the ecosystem services of the cropland. From 2007 to 2012, the planting area of corn and rapeseed in Minle County increased by 5.86 × 103 ha and 5.10 × 103 ha, respectively. Conversely, the planting area of wheat and barley was reduced by 3.26 × 103 ha and 6.34 × 103 ha, respectively. These changes directly caused the increase of the ecosystem services value of corn and rapeseed by 1062.82 × 104 USD and 842.54 × 104 USD, respectively. The resulting reduction in the ecosystem services value of wheat and barley was 488.24 × 104 USD and 828.29 × 104 USD, respectively. Besides, the total ecosystem services value of cropland increased by 1564.98 × 104 USD. Further analysis found that the change in the crop planting structure caused an increase in the ecosystem services value of cropland of 359.44 × 104 USD, with a contribution rate of 22.97% to the total increase. The expansion of corn caused the increase of the ecosystem services value of cropland by 151.65 × 104 USD, with a contribution rate of 9.69% to the total increase. The change in crop planting structure in Minle County increased not only the economic benefits of crop planting, but also the ecosystem services of cropland.

      PubDate: 2017-11-17T15:31:14Z
      DOI: 10.1016/j.pce.2016.09.003
      Issue No: Vol. 102 (2017)
       
  • The potential vulnerability of the Namib and Nama Aquifers due to low
           recharge levels in the area surrounding the Naukluft Mountains, SW Namibia
           
    • Authors: Winnie N. Kambinda; Benjamin Mapani
      Pages: 31 - 39
      Abstract: Publication date: December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 102
      Author(s): Winnie N. Kambinda, Benjamin Mapani
      The Naukluft Mountains in the Namib Desert are a high rainfall-high discharge area. It sees increased stream-, spring-flow as well as waterfalls during the rainy season. The mountains are a major resource for additional recharge to the Namib and Nama aquifers that are adjacent to the mountains. This paper aimed to highlight the potential vulnerability of the aquifers that surround the Naukluft Mountain area; if the strategic importance of the Naukluft Karst Aquifer (NKA) for bulk water supply becomes necessary. Chloride Mass Balance Method (CMBM) was applied to estimate rainfall available for recharge as well as actual recharge thereof. This was applied using chloride concentration in precipitation, borehole and spring samples collected from the study area. Groundwater flow patterns were mapped from hydraulic head values. A 2D digital elevation model was developed using Arc-GIS. Results highlighted the influence of the NKA on regional groundwater flow. This paper found that groundwater flow was controlled by structural dip and elevation. Groundwater was observed to flow predominantly from the NKA to the south west towards the Namib Aquifer in two distinct flow patterns that separate at the center of the NKA. A distinct groundwater divide was defined between the two flow patterns. A minor flow pattern from the northern parts of the NKA to the north east towards the Nama Aquifer was validated. Due to the substantial water losses, the NKA is not a typical karst aquifer. While the project area receives an average rainfall of 170.36 mm/a, it was estimated that 1–14.24% (maximum 24.43 mm/a) rainfall was available for recharge to the NKA. Actual recharge to the NKA was estimated to be less than 1–18.21% (maximum 4.45 mm/a) reflecting the vast losses incurred by the NKA via discharge. This paper concluded that groundwater resources of the NKA were potentially finite. The possibility of developing the aquifer for bulk water supply would therefore drastically lower recharge to surrounding aquifers that sustain local populations because all received rainfall will be utilized to maximise recharge to the NKA instead of surrounding aquifers.

      PubDate: 2017-11-17T15:31:14Z
      DOI: 10.1016/j.pce.2016.12.002
      Issue No: Vol. 102 (2017)
       
  • Climate change induced by Southern Hemisphere desertification
    • Authors: Ye Wang; Xiaodong Yan
      Pages: 40 - 47
      Abstract: Publication date: December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 102
      Author(s): Ye Wang, Xiaodong Yan
      Some 10–20% of global dry-lands are already degraded, and the ongoing desertification threatens the world's poorest populations. Studies on desertification effects are essential for humans to adapt to the environmental challenges posed by desertification. Given the importance of the much larger southern ocean to the global climate and the Southern Hemisphere (SH) climate changes in phase with those in the north, the biogeophysical effects of the SH desertification on climate are assessed using an Earth system model of intermediate complexity, MPM-2. This analysis focuses on differences in climate among the averages of simulations with desert expansion in different latitude bands by year 2000. The localized desertification causes significant global changes in temperature and precipitation as well as surface albedo. On the global scale, cooling dominates the SH desertification effects. However, the biogeophysical effects are most significant in regions with desertification, and the cooling is also prominent in northern mid-latitudes. Desert expansion in 15°–30°S reveals statistically most significant cooling and increased precipitation over the forcing regions during spring. The global and regional scale responses from desertification imply the climate teleconnection and address the importance of the effects from the SH which are contingent on the location of the forcing. Our study indicates that biogeophysical mechanisms of land cover changes in the SH need to be accounted for in the assessment of land management options especially for latitude band over 15°-30°S.

      PubDate: 2017-11-17T15:31:14Z
      DOI: 10.1016/j.pce.2016.03.009
      Issue No: Vol. 102 (2017)
       
  • Timescale differences between SC-PDSI and SPEI for drought monitoring in
           China
    • Authors: Haiyan Zhao; Ge Gao; Wei An; Xukai Zou; Haitao Li; Meiting Hou
      Pages: 48 - 58
      Abstract: Publication date: December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 102
      Author(s): Haiyan Zhao, Ge Gao, Wei An, Xukai Zou, Haitao Li, Meiting Hou
      The Palmer Drought Severity Index (PDSI) has been widely used to monitor drought. Its characteristics are more suitable for measuring droughts of longer timescales, and this fact has not received much attention. The Standardized Precipitation Evapotranspiration Index (SPEI) can better reflect the climatic water balance, owing to its combination of precipitation and potential evapotranspiration. In this study, we selected monthly average air temperature and precipitation data from 589 meteorological stations of China's National Meteorological Information Center, to compare the effects of applying a self-calibrating PDSI (SC-PDSI) and SPEI to monitor drought events in the station regions, with a special focus on differences of event timescale. The results show the following. 1) Comparative analysis using SC-PDSI and SPEI for drought years and characters of three dry periods from 1961 to 2011 in the Beijing region showed that durations of SC-PDSI-based dry spells were longer than those of 3-month and 6-month SPEIs, but equal to those of 12-month or longer timescale SPEIs. 2) For monitoring evolution of the fall 2009 to spring 2010 Southwest China drought and spring 2000 Huang-Huai drought, 3-month SPEI could better monitor the initiation, aggravation, alleviation and relief of drought in the two regions, whereas the SC-PDSI was insensitive to drought recovery because of its long-term memory of previous climate conditions. 3) Analysis of the relationship between SC-PDSI for different regions and SPEI for different timescales showed that correlation of the two indexes changed with region, and SC-PDSI was maximally correlated with SPEI of 9–19 months in China. Therefore, SC-PDSI is only suitable for monitoring mid- and long-term droughts, owing to the strong lagged autocorrelation such as 0.4786 for 12-month lagged ones in Beijing, whereas SPEI is suitable for both short- and long-term drought-monitoring and should have greater application prospects in China.

      PubDate: 2017-11-17T15:31:14Z
      DOI: 10.1016/j.pce.2015.10.022
      Issue No: Vol. 102 (2017)
       
  • Reception conditions of low frequency (LF) transmitter signals onboard
           DEMETER micro-satellite
    • Authors: M.Y. Boudjada; P.F. Biagi; E. Al-Haddad; P.H.M. Galopeau; B. Besser; D. Wolbang; G. Prattes; H. Eichelberger; G. Stangl; M. Parrot; K. Schwingenschuh
      Pages: 70 - 79
      Abstract: Publication date: December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 102
      Author(s): M.Y. Boudjada, P.F. Biagi, E. Al-Haddad, P.H.M. Galopeau, B. Besser, D. Wolbang, G. Prattes, H. Eichelberger, G. Stangl, M. Parrot, K. Schwingenschuh
      We analyse the flux density variation associated to low frequency (LF) broadcasting transmitters observed by the ICE electric field experiment onboard DEMETER micro-satellite, observed from 01st Jan. to 09th Dec. 2010. We select five stations localized around the Mediterranean and the Black seas: Tipaza (252 kHz, 02°28′E, 36°33′N, Algeria), Roumoules (216 kHz, 06°08′E, 43°47′N, Monte Carlo), Polatli (180 kHz, 32°25′E, 39°45′N, Turkey), Nadour (171 kHz, 02°55′W, 35°02′N, Morocco) and Brasov (153 kHz, 25°36′E, 45°40′, Romania). The detection of the LF transmitter signals by DEMETER micro-satellite is found to depend on the radiated power, the emitted frequency, and the orbit paths with regard to the location of the stations. This leads us to characterize the reception condition of the LF signals and to define time intervals where the detection probability is high. We show that LF signal are regularly recorded, each 12 days, when the satellite is above the broadcasting station. The signal intensity levels are principally significant during the solar activity. Hence we find that the solar and the geomagnetic activities are slightly correlated to the maxima of LF signal as recorded by DEMETER. Also we note a drop of the intensity level several days before the occurrence of earthquakes in/around the Mediterranean and Black seas.

      PubDate: 2017-11-17T15:31:14Z
      DOI: 10.1016/j.pce.2016.07.006
      Issue No: Vol. 102 (2017)
       
  • Physical and Economic Processes of Ecosystem Services Flows
    • Authors: Hongbo Su; Sudhagar Nagarajan; Jinwei Dong
      Pages: 1 - 2
      Abstract: Publication date: October 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 101
      Author(s): Hongbo Su, Sudhagar Nagarajan, Jinwei Dong


      PubDate: 2017-12-18T09:34:48Z
      DOI: 10.1016/j.pce.2017.10.001
      Issue No: Vol. 101 (2017)
       
  • Evaluation of ecosystem service based on scenario simulation of land use
           in Yunnan Province
    • Authors: Hong Zhang; Xiaoli Liao; Tianlin Zhai
      Abstract: Publication date: Available online 26 December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Hong Zhang, Xiaoli Liao, Tianlin Zhai
      Climate change and rapid urbanization are important factors restricting future land use. Situational analysis, as an important foundation for the optimization of land use, needs to focus on the impact of climate factors and socio-economic factors. In this paper, the Markov model and the DLS (Simulation of Land System Dynamics) model are combined for the first time, and the land use pattern in 2020 is simulated based on the data of land use in 2000 and 2010 as well as the climate, soil, topography and socio-economic factors of Yunnan Province. In his paper, we took Yunnan Province as the case study area, and selected 12 driving factors by logistic regression method, then the land use demands and layout of Yunnan Province in 2020 has been forecasted and simulated under business as usual (BAU) scenario and farmland protection (FP) scenario and the changes in ecosystem service value has been calculated. The result shows that: (1) after the regression analysis and ROC (Relative Operating Characteristics) test, the 12 factors selected in this paper have a strong ability to explain the land use change in Yunnan Province. (2) Under the two scenarios, the significant reduction of arable land area is a common feature of land use change in Yunnan Province in the future, and its main land use type will be construction land. However, under FP scenario, the current situation where construction land encroach on arable land will be improved. Compared with the change from 2000 to 2010, the trend of arable land, forest land, water area, construction land and unused land will be the same under the two scenarios, whereas the change trend of grassland was opposite. (3) From 2000 to 2020, the value of ecosystem services in Yunnan Province is on the rise, but the ecosystem service value under FP scenario is higher than that of the ecosystem services under BAU scenario. In general, land use in 2020 in Yunnan Province continues the pattern of 2010, but there are also significant spatial differences. Under the BAU scenario, the construction land is mainly in the south of Lijiang City and the northeastern part of Kunming. Under the FP scenario, the new construction land is concentrated near the Lashi dam in northern Yunnan Province, and the high-quality arable land in the valley will be better protected. The research results can provide reference for the optimization of land use pattern in Yunnan Province, and provide scientific basis for land use management and planning. Based on the value of ecosystem services, we should implement the policy of strict protection of arable land, both to ensure food supply and promote the healthy development of ecological environment.

      PubDate: 2017-12-26T19:21:10Z
      DOI: 10.1016/j.pce.2017.12.001
       
  • Validation and verification of lawful water use in South Africa: An
           overview of the process in the KwaZulu-Natal Province.
    • Authors: E. Kapangaziwiri; J. Mwenge Kahinda; S. Dzikiti; A. Ramoelo; M. Cho; R. Mathieu; M. Naidoo; A. Seetal; H. Pienaar
      Abstract: Publication date: Available online 25 December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): E. Kapangaziwiri, J. Mwenge Kahinda, S. Dzikiti, A. Ramoelo, M. Cho, R. Mathieu, M. Naidoo, A. Seetal, H. Pienaar
      South Africa is a water-stressed country which has, over the years, strived to adopt a rational, just and equitable way to manage this limited resource. The National Water Act (Act No.36 of 1998) (NWA) provides the legal framework to achieve this objective. Since 2003, the government embarked on a national process to: validate (confirm the quantum of), and; verify (establish the lawfulness of) water uses that exceed domestic requirements. The objective of the process is to determine how much water is allocated for: (1) existing lawful use in accordance with specific requirements of the NWA, and; (2) current water uses. The process identified users with or without registered use entitlements, whether claims for registered uses were correct, under-estimated, over-estimated or false; and confirmed the lawfulness of each water use in accordance with water legislation that pre-dated the NWA. The process included identifying land and non-land based water uses (industrial, mining and bulk potable water supplies, irrigation, crop types and impoundments) using remote sensing (RS) techniques for both a qualifying (defined as two years before the enactment of the NWA) and the current periods. Using this as a basis, volumetric crop irrigation requirements were then estimated using the South African Procedure for estimating irrigation WATer requirements (SAPWAT), while the Gush curves were used to quantify Stream Flow Reduction Activities (SFRAs) for commercially afforested areas. The boundaries of farm reservoirs were delineated from RS and the volumes calculated using a regression approach. Estimates of the irrigation water requirements, SFRAs and reservoir volumes formed the basis for interaction between the Department of Water and Sanitation (DWS) and water users to confirm their uses; and subsequently, to update the DWS Water Authorisation and Registration Management System (WARMS), a database of water users. While WARMS initially indicated a total of approximately 16 000 registered users in the KwaZulu-Natal Province, following the RS analysis up to 6000 potential additional water users have been identified, mostly currently unregistered, who are expected to be registered in the updated database. Despite certain process methodology challenges and limitations, it forms a critical basis for all other aspects of water management, informs macro- and micro-water resource planning, water allocation reform, as well as water use compliance, monitoring and enforcement.

      PubDate: 2017-12-26T19:21:10Z
      DOI: 10.1016/j.pce.2017.12.002
       
  • When good practices by water committees are not relevant: Sustainability
           of small water infrastructures in semi-arid mozambique
    • Authors: Ducrot
      Abstract: Publication date: December 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C, Volume 102
      Author(s): Raphaëlle Ducrot
      This paper explores the contradiction between the need for large scale interventions in rural water supplies and the need for flexibility when providing support for community institutions, by investigating the implementation of the Mozambique - National Rural Water Supply and Sanitation Program in a semi-arid district of the Limpopo Basin. Our results showed that coordinated leadership by key committee members, and the level of village governance was more important for borehole sustainability than the normative functioning of the committee. In a context in which the centrality of leadership prevails over collective action the sustainability of rural water infrastructure derives from the ability of leaders to motivate the community to provide supplementary funding. This, in turn, depends on the added value to the community of the water points and on village politics. Any interventions that increased community conflicts, for example because of lack of transparency or unequitable access to the benefit of the intervention, weakened the coordination and the collective action capacity of the community and hence the sustainability of the infrastructures even if the intervention was not directly related to water access. These results stress the importance of the project/program implementation pathway.

      PubDate: 2017-11-17T15:31:14Z
       
  • Projected land use changes impacts on water yields in the karst mountain
           areas of China
    • Authors: Yanqing Lang; Wei Song; Xiangzheng Deng
      Abstract: Publication date: Available online 6 November 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Yanqing Lang, Wei Song, Xiangzheng Deng
      Human-induced land use changes over short time scales have significant impacts on water yield, especially in China because of the rapid social economic development. As the biggest developing country of the world, China's economy is expected to continuously grow with a high speed in the next few decades. Therefore, what kind of land use changes will occur in the future in China' How these changes will influence the water yields' To address this issue, we assessed the water yields in the karst mountain area of China during the periods of 1990–2010 and 2010–2030 by coupling an Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and a Conversion of Land Use and its Effects (CLUE) model. Three different land use scenarios i.e. natural growth, economic development, and ecological protection, were developed in 2030 using the CLUE model. It was concluded that, given land use changes between 1990 and 2010, total water yields in the karst mountain area are characterized by a trend towards fluctuating reduction. However, total water yields of 2030 in the economic development scenario revealed an increase of 1.25% compared to the actual water yields in 2010. The economy development in karst mountain areas of China in the future has a slight positive influence on water yields.

      PubDate: 2017-11-17T15:31:14Z
      DOI: 10.1016/j.pce.2017.11.001
       
  • Association between forestry ecological engineering and dust weather in
           Inner Mongolia: A panel study
    • Authors: Huang Jixia; Zhang Qibin; Tan Jing; Yue Depeng; Ge Quansheng
      Abstract: Publication date: Available online 2 November 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Huang Jixia, Zhang Qibin, Tan Jing, Yue Depeng, Ge Quansheng
      Forestry ecological engineering projects in Western China include the Three-North Shelter Forest Project (TNSFP), the Natural Forest Protection Project (NFPP), the Grain for Green Project (GGP) and the Beijing-Tianjin Sandstorm Source Project (BTSSP). Such projects play an important role in the control of dust weather in Western China. In this research, data on the frequency of sandstorms, sand-blowing and dust-floating weather, the area of four forestry ecological engineering projects, wind, rainfall and vegetation coverage from 2000 to 2010 were collected based on the unit of prefecture-level cities in Inner Mongolia. The panel-data model was used to analyze the quantitative association between forestry ecological engineering and dust weather. The results indicate that wind has a strong promotional effect on dust weather, while forestry ecological engineering and rainfall have a containment effect. In addition, the impacts of the four studied forestry ecological engineering projects on dust weather differ. For every increase of 1000 km2 in the Three-North Shelter Forest Project, the annual number of days of sandstorm weather decreased by 4 days. Similarly, for every increase of 1000 km2 in the Beijing-Tianjin Sandstorm Source Project, the sand-blowing weather decreased by 4.4 days annually. In addition, NFPP and GGP have a more obvious inhibitory effect on the dust-floating weather.

      PubDate: 2017-11-17T15:31:14Z
      DOI: 10.1016/j.pce.2017.10.003
       
  • Seasonal variations in the water quality of a tropical wetland dominated
           by floating meadows and its implication for conservation of Ramsar
           wetlands
    • Authors: Chongpi Tuboi; Michelle Irengbam; Syed Ainul Hussain
      Abstract: Publication date: Available online 6 October 2017
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Chongpi Tuboi, Michelle Irengbam, Syed Ainul Hussain
      The Loktak Lake is a palustrine wetland located in the Barak-Chindwin river basin of Northeast India. The Lake is characterized by floating meadows of various thickness which support severely depleted endangered Eld's deer (Rucervus eldii) and sympatric hog deer (Axis porcinus). The southern part of the Lake is protected as Keibul Lamjao National Park as the last remaining habitat of the Eld's deer in India. The Loktak Lake has been included in the Montreux record as it is changing its ecological character due to anthropogenic pressures especially due to water pollution. We examined the seasonal pattern of water quality of Loktak Lake and compared it with the Keibul Lamjao National Park with a view to suggest measures for removal of this wetland from the Montreux record and for improved conservation. The evaluation of spatio-temporal variations in the water quality parameters over two years was carried out using multivariate statistical analysis. Hierarchical cluster analysis grouped the 11 sampling sites into four groups, less polluted, medium polluted, highly polluted and most polluted and the 12 months into three time periods. Principal Component Analysis identified three factors in the data structure which explained 92.9% of the total variance of the data set which was used to group the selected parameters according to common features and to evaluate the influence of each group on the overall variation in water quality. Significant difference in terms of water quality parameters were observed across different parts of the lake and seasons (ANOVA, p < 0.05). Our study revealed that the Loktak Lake is hypereutrophic leading to decreased water quality that has adverse impacts on ecosystem level processes. Restoration of the Lake requires an integrated approach in reduction of nutrient inputs, enhanced flushing mechanism and restoration of environmental flow which has been disrupted due to damming.

      PubDate: 2017-10-12T07:57:35Z
      DOI: 10.1016/j.pce.2017.09.001
       
 
 
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