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Prem Kumar Gupta - One of the best experts on this subject based on the ideXlab platform.
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Fate of Metals in Relation to Water and Sediment Properties in a Subtropical Lake in Central Himalaya, India
Archives of Environmental Contamination and Toxicology, 2017Co-Authors: Shaikhom Inaotombi, Prem Kumar GuptaAbstract:Lakes of Himalaya are one of the most fragile ecosystems on earth. Tourism and urban development in the upland region strongly affect its water resources. The high rate of Sedimentation and organic matter deposition alters the ecological state of Sediment bed, which indirectly influences on dynamics of metallic elements. We investigated spatial and temporal variations of water and Sediment Characteristic in Lake Sattal of Central Himalaya, India. Samples were collected seasonally from four sampling locations from January 2011 to December 2012. Pearson’s correlation and Canonical correspondence analysis (CCAs) were applied to examine the dynamics and behaviors of heavy metals. Concentrations of elements were in the order of fluoride (Fl) > zinc (Zn) > copper (Cu) > iron (Fe) > manganese (Mn). Sand size fraction was higher in the littoral zone while clay particle was dominant in the profundal zone of the lake. Dissolved oxygen at Sediment–water-interface (SWI) and water temperature were the major factors influencing the dynamics of metallic contents in the water column. Spatially, total organic matter (TOM) was higher in the deeper portion of the lake. Our study revealed that mobility of Fe is temperature-dependent, whereas speciation of Mn and Cu are primarily controlled by the suboxic condition of SWI in organic-rich site. Upland lakes are more vulnerable to anoxic condition and have severe implications on heavy metals speciation. Proper implementation of land use policies and management practices, including stormwater detention, can be integrated into resolving such problems.
Shaikhom Inaotombi - One of the best experts on this subject based on the ideXlab platform.
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Fate of Metals in Relation to Water and Sediment Properties in a Subtropical Lake in Central Himalaya, India
Archives of Environmental Contamination and Toxicology, 2017Co-Authors: Shaikhom Inaotombi, Prem Kumar GuptaAbstract:Lakes of Himalaya are one of the most fragile ecosystems on earth. Tourism and urban development in the upland region strongly affect its water resources. The high rate of Sedimentation and organic matter deposition alters the ecological state of Sediment bed, which indirectly influences on dynamics of metallic elements. We investigated spatial and temporal variations of water and Sediment Characteristic in Lake Sattal of Central Himalaya, India. Samples were collected seasonally from four sampling locations from January 2011 to December 2012. Pearson’s correlation and Canonical correspondence analysis (CCAs) were applied to examine the dynamics and behaviors of heavy metals. Concentrations of elements were in the order of fluoride (Fl) > zinc (Zn) > copper (Cu) > iron (Fe) > manganese (Mn). Sand size fraction was higher in the littoral zone while clay particle was dominant in the profundal zone of the lake. Dissolved oxygen at Sediment–water-interface (SWI) and water temperature were the major factors influencing the dynamics of metallic contents in the water column. Spatially, total organic matter (TOM) was higher in the deeper portion of the lake. Our study revealed that mobility of Fe is temperature-dependent, whereas speciation of Mn and Cu are primarily controlled by the suboxic condition of SWI in organic-rich site. Upland lakes are more vulnerable to anoxic condition and have severe implications on heavy metals speciation. Proper implementation of land use policies and management practices, including stormwater detention, can be integrated into resolving such problems.
Ismail Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Composition of Harpacticoida (Crustacea: Copepoda) and effect of rand reclamation activity in seagrass area of Sungai Pulai, Malaysia
2018Co-Authors: Kassim Zaleha, Nordin, Amira Syahidah, Ismail AhmadAbstract:Sungai Pulai is one of the largest areas for riverine mangroves which associated with other important ecosystem, the seagrass bed and mud flat located in the Tebrau Straits of Johor. The nearby areas experience rapid development activities including land reclamation. This study is carried out to investigate the composition of copepods particularly the Harpacticoida group in the seagrass bed continuously exposed to such land activities. Core samples were taken from three stations which consist of vegetation and non-vegetation areas in the evening during lowest tide in October and November 2017. All samples were fixed with 10% buffered formalin added with Rose Bengal stain. Eight families of harpacticoids were identified; Porcellidiidae Sars., Diossaccidae Sars., Longipediidae Sars, Lang., Laophontidae T. Scott., Canuellidae Lang., Tisbidae Stebbing, Lang , Paramesochridae Lang and Harpacticidae Sars. All families could be found in both vegetated and non-vegetated Sediment except for Porcellidiidae Sars which was absent in the non-vegetated Sediment. All families showed certain similarity in occurrence within the area of the vegetation or the non-vegetated area. Total Organic Matter (TOM) and Sediment Characteristic correlated significantly with different families particularly with Canuellidae, Porcellidiidae, Longipediidae and Tisbidae. There is a strong indication that reclamation activity alter the environmental condition thus affect the composition of harpacticoid in term of density and taxonomic group
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Composition of Harpacticoida (Crustacea: Copepoda) during land reclamation activity in seagrass area of Sungai Pulai, Malaysia
2018Co-Authors: Kassim Zaleha, Nordin, Amira Syahidah, Ismail AhmadAbstract:Sungai Pulai is one of the largest areas for riverine mangroves which associated with other important ecosystem, the seagrass bed and mud flat located in the Tebrau Straits of Johor. The nearby area is experienced rapid development activities including land reclamation. This study is carried out to investigate the composition of copepods particularly the Harpacticoida group in the seagrass bed continuously exposed to such land activities. Core samples were taken from three stations which consist of vegetation and non vegetation areas in the evening during lowest tide in October and November 2017. All samples were fixed with 10% buffered formalin added with Rose Bengal stain. Seven families of harpacticoids were identified, Porcellidiidae Sars., Diossaccidae Sars., Longipediidae Sars, Lang., Laophontidae T. Scott., Canuellidae Lang., Tisbidae Stebbing, Lang and Paramesochridae Lang. Porcellidiidae. Result revealed that there is a significant different for Porcellidiidae density (F=5.512, p=0.002) between all harpacticoid copepod family member in all station except with Diosaccidae in the vegetation area. Overall, 2-Way Anova by using Duncan test showed the density of harpacticoid copepods in vegetation area is highly significant compared to non-vegetation area (F=4.512, p=0.005). In vegetation area, Pearson’s Correlation analysis summarized that Cannuellidae has strong correlation with Total Organic Matter, TOM (R=0.864) if compared to other families. In first sampling, family Porcellidiidae showed high significant correlation towards mean grain size and sorting condition of Sediment which is R=1.000, p=0.018 and R=-0.997,p=0.049 respectively. Longipedidae also gave significant correlation towards sorting condition which is R=-0.999, p=0.025. Nonetheless, Tisbidae family showed high significant correlation to mean grain size which R=0.998, p=0.041during the second sampling. Porcellidiidae which is known as obligate phytal species does not affected by the amount of TOM but with Sediment Characteristic along with Longipedidae and Tisbidae, which indicate their composition could be easily affected by the change of Sediment in the area
Liang He - One of the best experts on this subject based on the ideXlab platform.
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littoral slope water depth and alternative response strategies to light attenuation shape the distribution of submerged macrophytes in a mesotrophic lake
Frontiers in Plant Science, 2019Co-Authors: Liang He, Yao Wu, Wei Li, Huan Zhang, Xiaolin Zhang, Leyi Ni, Sabine HiltAbstract:Light is a major limiting resource in aquatic ecosystems and numerous studies have investigated the response of submerged macrophytes to low light conditions. However, few studies have tested whether different light response strategies can also have consequences for macrophyte distribution along different littoral slopes in lakes, which are known to affect macrophyte biomass due to differences in drag forces and Sediment Characteristic. In this study, we tested 1) whether two macrophyte species of different growth forms (canopy-forming: Potamogeton maackianus, rosette-type: Vallisneria natans) differ in their response strategies to low light conditions and 2) how these responses influence their distribution along different basin slopes in the mesotrophic Lake Erhai, China. We hypothesized that the canopy-forming species responds to low light conditions at deeper sites by stem elongation while the rosette-type species increases its shoot chlorophyll content. As a consequence, P. maackianus should have a higher susceptibility to drag forces and thus prevail at sites with lower slopes. Sites with higher slopes should offer a niche for rosette-type species like V. natans that can better withstand drag forces. We surveyed the distribution and abundance of the two macrophyte species at 527 sampling points along 97 transects in Lake Erhai and measured their height, leaf and stem/rhizome biomass, and leaf chlorophyll a content at different water depths. Our results confirmed stem elongation as a strategy to low light conditions by the canopy-forming species P. maackianus, while V. natans produced more chlorophyll a per shoot biomass at deeper sites to tolerate shading. As hypothesized, these alternative response strategies to low light conditions resulted in a trade-off regarding the plants ability to grow at different basin slopes. P. maackianus was dominant at sites with low-moderate slope (0-4%) and low-moderate water depth (2-4 m), while sites with high basin slope (4-7%) combined with moderate-high water depth (3-5 m) were predominantly colonized by V. natans. The latter habitat thus represents a potential refuge for rosette-type macrophyte species that are often outcompeted when shading increases during eutrophication.
W U Mueller - One of the best experts on this subject based on the ideXlab platform.
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an unusual fluvial to tidal transition in the mesoarchean moodies group south africa a response to high tidal range and active tectonics
Sedimentary Geology, 2006Co-Authors: Kenneth A Eriksson, Edward L Simpson, W U MuellerAbstract:Abstract The Moodies Group in the Dycedale Syncline, Barberton Greenstone Belt consists of a 100–130 m-thick upward-fining succession that exhibits a transition from fluvial to tide-modified Sedimentation. A basal, 10–30 m-thick conglomerate–sandstone interval of alluvial origin is overlain by stacked upward-fining, decimeter- to meter-scale cycles within which three facies are recognized: 1) conglomerate lag; 2) cross-bedded sandstone; and 3) interlaminated sandstone–siltstone and mudstone. Within the cycles, the abundance of mudstone drapes increases upwards. Structureless conglomerates and cross-beds lacking mudstone drapes record braided-alluvial processes. In contrast, cross-beds with mudstone drapes and interlaminated sandstone–siltstone and mudstone are products of flows modified by various tidal beats. Sand and/or silt transport took place during the ebb and flood stages and mudstone accumulated during slack water phases. Alternating thick–thin laminations reflect dominant and subordinate, twice-daily tides. Thicker groupings of foresets and thicker intervals of vertically stacked sandstone–siltstone and mudstone laminations are interpreted as spring tide deposits whereas thinner groupings of foresets and thinner laminations record neap tides. Desiccated mudstone drapes on foresets indicate that bedforms rarely were locally exposed during some portion of the tidal cycle. Abundant exposure structures in the interlaminated sandstone–siltstone and mudstone facies indicate that the cycles are upward shoaling. The stacked upward-fining cycles are attributed to alternating subaerial exposure and fluvial influx followed by marine inundation, probably related to absolute sea level fluctuations. Lack of high-order vegetation on the Archean landscape promoted rapid lateral migration or avulsion of tidally influenced fluvial channels. The association of facies within the 100–130 m-thick upward-fining succession is comparable to Holocene and ancient paleovalley fills characterized by basal alluvial gradational upwards into estuarine facies. However, in the absence of vegetation, the land–ocean interface in the Archean probably consisted of laterally extensive fan or braid deltas rather than point sources of Sediment Characteristic of most modern rivers. The abrupt up-section change from syntectonic, high-energy, alluvial–fluvial flash flood deposits to tide-influenced Sedimentation implies a proximal source that provided Sediment to a shoreline influenced by strong tidal action. Possible Holocene analogues are orogenic settings such as the Canterbury Plains of New Zealand, the Indo-Gangetic Plains of India and strike-slip settings such as the Gulf of Aqaba but all three examples lack a direct transition to tidally influenced Sedimentation.