Watershed Ecology and the Environment最新文献

{"title":"Hydrological connectivity, surface water quality and distribution of fish species within sub-locations of an urban oxbow lake, East India","authors":"Shubhajit Saha ,&nbsp;Azubuike V. Chukwuka ,&nbsp;Dip Mukherjee ,&nbsp;Nimai Chandra Saha ,&nbsp;Aina O. Adeogun","doi":"10.1016/j.wsee.2022.04.001","DOIUrl":"10.1016/j.wsee.2022.04.001","url":null,"abstract":"<div><p>Ecological processes and distribution of biodiversity within river floodplains are driven by the hydrological regime of the area. The relationship between fish abundance/diversity and surface water quality at four impact points of the Sashadanga oxbow lake was examined based on hydrological connectivity (distance of lake sections from parent channel; density of buffer vegetation and hydrological phases of seasons). Fish sample populations (n = 1440) belonging to 10 orders showed greater numerical abundance in the pre-and post-flooding phases. Oxbow sites proximal to the parent channel showed higher comprehensive pollution index (CPI), higher dominance and lower species evenness during the pre-monsoon (minor flooding) and vice versa during the monsoon and post-monsoon (greater flooding periods). Diversity descriptors using curve/asymptote based on Hill’s numbers indicate significant site-specific fish diversity within the oxbow lake at different seasons. Discriminant analysis revealed that change in temperature, turbidity and concentration of inorganic nitrogen were significant predictors in differentiating the quality of the different sites of the lake. Principal component analysis (PCA) revealed that the relative abundance of each species order across sites was significantly influenced by changes in seasons and physicochemical parameters, and showed a weak association with the density of buffer vegetation at sites. Depending on the distance of oxbow areas to the parent channel, the combination of periodic flooding, riparian buffer and lake morphology define the degree of hydrological connectivity which in turn affects the composition and abundance of fish communities at different points of the lake.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 44-58"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S258947142200002X/pdfft?md5=8c1beb8a020b63f6f327e6f293ac153d&pid=1-s2.0-S258947142200002X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86849943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring biosorption properties of Litchi chinensis peel for a cationic dye Rhodamine 6G in Liquid/Solid phase system: Kinetics and equilibrium studies","authors":"P. Mercy Jasper ,&nbsp;S. Sumithra ,&nbsp;S. Jameer Ahammad ,&nbsp;M. Madakka","doi":"10.1016/j.wsee.2022.08.001","DOIUrl":"10.1016/j.wsee.2022.08.001","url":null,"abstract":"<div><p>The Rhodamine 6G (Rh6G), a cationic dye is actively being used as a potentially tracing dye in the field of biotechnology for immunological studies. The peel powder of <em>Litchi Chinensis</em> was employed in native condition to explore the sorption properties at different experimental conditions like initial dye concentration, contact time, dosage of biosorbent, temperature and pH. The detailed characteristics of <em>Litchi chinensis</em> peel before and after adsorption were performed by using sophisticated instruments like SEM-EDX, FTIR, BET and XRD. From the adsorption studies it was observed that the equilibrium data followed Pseudo-second order rate kinetics and Freundlich isotherm. The Langmuir adsorption capacity (Q_o) was found to be 6.66 mg/g, and the adsorption process was spontaneous and exothermic in nature (based on ΔG, ΔH and ΔS values). All the laboratory experiments proven to be an evident for the <em>Litchi chinensis</em> peel as an efficient biosorbent for the removal of Rhodamine 6G in the liquid/solid phase system.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 66-72"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471422000043/pdfft?md5=74e069be941c006e3a24f18c8359c602&pid=1-s2.0-S2589471422000043-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73067423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of applying imazapyr on the control of Spartina alterniflora and its eco-environments in the Yellow River Delta, China","authors":"Xue Mo ,&nbsp;Jingqiu Chen ,&nbsp;Yueyan Pan ,&nbsp;Mingxiang Zhang ,&nbsp;Zhenming Zhang ,&nbsp;Jiakai Liu","doi":"10.1016/j.wsee.2022.11.002","DOIUrl":"10.1016/j.wsee.2022.11.002","url":null,"abstract":"<div><p>The invasion of <em>Spartina alterniflora</em> has threatened and damaged coastal wetlands in China, therefore, control and removal of this severe invasive plant are urgently needed. Green chemical control is an effective and low-cost method that can be used for large-scale removal of invasive specie. To study the control effect of imazapyr on <em>S. alterniflora</em> and evaluate its impact on other species and the wetland environment, a control experiment was set up in the Yellow River Delta Reserve in Shandong Province in May 2021. A total of 9 treatments were set up in the experiment: 25 % (W) imazapyr water (main agent), three treatments with dose gradients of 3.0, 6.0, and 9.0 L/acre, and the main agent at a dose of 6.0 L/acre with six treatments of AGE 809 (adjuvant A) and AGE 852 (adjuvant B) with dose gradients of 1.3, 2.6, and 5.2 L/acre, respectively. The results showed that after 60 days of application, the control efficiency of <em>Spartina alterniflora</em> was over 90 %, and the residual amount was small in the plots with the main agent additive &lt; 6.0 L/acre. Among them, the residues on leaves were 0.499 ∼ 2.822 mg/kg, the residues in soil ranged from 0.0012 to 0.0714 mg/kg, and were from not detected in water to 8.8E-4 mg/kg. During the experiment, there were significant differences in soil physicochemical properties among different treatments, and imazapyr significantly affected on the availability of soil C, N, and P at the stage of large chemical residues (<em>P</em> &lt; 0.05). In addition, imazapyr was not toxic to the benthic community and increased from 168.72/m³ to 633.75/m³ in 60 days after spraying. This study provides a theoretical basis, data support, and technical support for applying herbicides to control <em>S. alterniflora</em> in coastal wetlands of China.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 211-218"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471422000134/pdfft?md5=e190b77ce7126f447e15ca3879cb2860&pid=1-s2.0-S2589471422000134-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78083721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contamination by heavy metals from mining activities: An ecological impact assessment of Mura and Kimpulande Rivers, Democratic Republic of the Congo","authors":"Alex Banze wa Mutombo ,&nbsp;Emmanuel K. Atibu ,&nbsp;Jean Mbuya wa Mutombo ,&nbsp;Emery M. Kalonda ,&nbsp;Elysée N. Bakatula ,&nbsp;Valentin N. Kanda ,&nbsp;Ruben K. Koy ,&nbsp;Crispin K. Mulaji ,&nbsp;Fernando P. Carvalho ,&nbsp;John Poté","doi":"10.1016/j.wsee.2022.10.004","DOIUrl":"10.1016/j.wsee.2022.10.004","url":null,"abstract":"<div><p>The contamination levels and distribution of heavy metals were assessed in riverbed sediments and water column samples from Mura and Kimpulande Rivers, both impacted by copper-cobalt and gold mining activities. Analyses were performed using inductively coupled plasma-mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS), and atomic fluorescence spectrometry (AFS). Results showed high concentrations of Ni, Cu, Zn, As, Cd, and Hg in water samples. The concentrations of As, Cd, and Hg in water from both rivers exceeded the limits set in Democratic Republic of the Congo (DRC) legislation on requirements for mine water discharges. High concentrations were found also for Cu, Cr, Zn, As, Cd, Pb, and Hg in river sediments and were assessed against sediment quality guidelines for the protection of aquatic life. The Enrichment factor (EF) and the Geoaccumulation index (Igeo) values revealed extremely severe enrichment of Cu, Co, As, and Cd and extreme pollution by Cu and Co in sediment samples demonstrating high contamination of these rivers. The results from calculated ecologic risk factors revealed that aquatic ecosystems in the investigated rivers are at risk. Therefore, a review of current mining practices is needed and the urgent enforcement of good practices is recommended in order to protect the environment and public health.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 148-157"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471422000110/pdfft?md5=51a9d0d44522bf6191af12d6599c8479&pid=1-s2.0-S2589471422000110-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79075530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metal accumulation in two crab species from the Woji Creek (Nigeria) and human health risk assessment due to crab consumption: Callinectes sapidus and Cardisoma armatum","authors":"Owhonda Chikeru Ihunwo ,&nbsp;Millicent Uzoamaka Ibezim-Ezeani ,&nbsp;Amir Reza Shahabinia ,&nbsp;Mark Obinna Onyema ,&nbsp;Prince Chinedu Mmom ,&nbsp;Estefanía Bonnail","doi":"10.1016/j.wsee.2022.11.003","DOIUrl":"10.1016/j.wsee.2022.11.003","url":null,"abstract":"<div><p>This study evaluates the concentrations of Cd, Cr, Pb, Ni, As and Cu in water, sediment and tissues (gill, muscle, hepatopancreas) of two crab species (<em>Callinectes sapidus</em> and <em>Cardisoma armatum</em>) collected from the Woji Creek in Niger Delta, Nigeria. As well as the health risk of consuming the crabs was determined. Mean values of metals in surface water revealed concentrations (mg/L) of a trend of Pb (3.252) &gt; Cu (2.328) &gt; Cr (1.590) &gt; Cd (0.146) &gt; Ni (0.109) and in sediments, the trend was in the order Pb (140.930) &gt; Ni (37.481) &gt; Cr (29.984) &gt; Cu (21.001) &gt; Cd (8.910). Hepatopancreas of the crabs accumulated higher concentrations of Cd and Pb; with mean concentrations of Cd and Pb of 0.110 ± 0.008 mg/kg and 1.364 ± 0.060 mg/kg in <em>Callinectes amnicola</em>, and 0.112 ± 0.008 mg/kg and 0.735 ± 0.026 mg/kg in <em>Cardisoma armatum</em> respectively. In the tissues of the three crab species, Pb and Cr were highest; while As was very low in the crab species. The HI was below 1 for males and females (adults and children) which indicates no risk to health from consumption of the edible crab species. Although the risk due to the consumption of these is low, they could be a dietary source of chronic doses of metals to humans.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 169-176"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471422000146/pdfft?md5=f6e86e1a78ce2a00eb0efad972fa6068&pid=1-s2.0-S2589471422000146-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75430735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of ecosystem health status using benthic diversity as tools in coastal sediments off the South West Coast, India","authors":"D.B. Arya ,&nbsp;Prince S. Godson ,&nbsp;Salom Gnana Thanga Vincent ,&nbsp;P. Selvaraj ,&nbsp;S. Krishnakumar ,&nbsp;N.S. Magesh","doi":"10.1016/j.wsee.2022.10.003","DOIUrl":"10.1016/j.wsee.2022.10.003","url":null,"abstract":"<div><p>The southwest coast of India is densely populated and experiences a wide range of natural and anthropogenic pressures. The diversity of macro and meiobenthos was documented in order to assess the ecosystem health of an anthropogenically impacted coastal ecosystem for the first time along the southwest coast of Tamil Nadu. Offshore sediment and water samples (n = 63) were collected from 14 sampling stations using the grid sampling method. Water and sediment samples were analysed for environmental variables such as pH, temperature, electrical conductivity (EC), total dissolved solids (TDS), salinity, sulphate, dissolved oxygen (DO), carbohydrate (CHO), protein, lipid, labile organic matter (LOM), total organic carbon (C_org), total organic matter (TOM) and sediment texture. Benthic macro and meiobenthos were isolated and identified using standard identification keys. A total of 5 phyla of macrobenthos with 29 species and 5 phyla of meiobenthos with 60 species were identified in the study area. Relative abundance analysis showed that the largest numbers of species belonged to Polychaeta for macrobenthos and foraminifera for meiobenthos. Redundancy analysis indicated that sediment carbohydrate content was the highest determining factor for explaining variation in the diversity of benthos. AMBI &amp; M−AMBI results revealed that among the 14 stations, 2 were categorized as “poor” and 9 as “bad”. Multiple anthropogenic activities in the coastal environment leading to increased organic matter input have resulted in a decline in the ecosystem health of this region, which warrants site-specific management to control organic pollution.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 135-147"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471422000109/pdfft?md5=4f0a8d2eb2a45c91805dcecd7f4a51ea&pid=1-s2.0-S2589471422000109-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77476027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioaccumulation of heavy metals in edible tissue of crab (Scylla serrata) from an estuarine Ramsar site in Kerala, South India","authors":"E. Sherly Williams ,&nbsp;V. Lekshmi Priya ,&nbsp;L. Razeena Karim","doi":"10.1016/j.wsee.2022.06.001","DOIUrl":"10.1016/j.wsee.2022.06.001","url":null,"abstract":"<div><p>Wetlands are under severe threat due to anthropogenic activities and pollutants. Many pollutants such as heavy metals may accumulate to a hazardous level. In the present study, <em>Scylla serrata</em>, the mud crab and associated sediments were collected from three sites of Ashtamudi lake, the Ramsar site, to investigate the bioaccumulation of heavy metals Cadmium, Chromium, Copper, Lead and Zinc. Elemental analysis in the sediment sample showed that Cadmium and Chromium were found to be above USEPA and CCME limits and Copper was found to be above CCME limit on site 1. In site 2, Chromium was found to be above USEPA and CCME limits. In all the three sites, Lead and Zinc are below the permissible limit. Bioaccumulation status of heavy metals in the muscle of Scylla serrata with respect to the sites are in the order of site 1 &gt; site 2 &gt; site. The heavy metals Cadmium, Chromium and Lead were found to be above the permissible limit in site 1 and site 2, whereas Copper and Zinc concentrations in the muscle of crab from Ashtamudi wetland are below levels of concern for human consumption. A number of histological alterations such as splitting of muscle fibres, focal area of necrosis and muscular oedema were noticed in the samples. The result clearly indicates the fact that <em>S. serrata</em> undergoes intensified stress, when exposed to heavy metal contamination. Knowledge of metal concentrations in shell fish and fin fish are important both with respect to nature management and human consumption of fish.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 59-65"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471422000031/pdfft?md5=4f7feb9809effc0888fb4fe77de75bfb&pid=1-s2.0-S2589471422000031-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89612725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of historical landscape changes in Lake Victoria Basin, Kenya, using remote sensing multi-spectral indices","authors":"Dancan O. Onyango ,&nbsp;Stephen B. Opiyo","doi":"10.1016/j.wsee.2021.12.001","DOIUrl":"10.1016/j.wsee.2021.12.001","url":null,"abstract":"<div><p>The Kenyan Lake Victoria basin has been experiencing land degradation and overexploitation as seen in various landscape changes. Quantifying and understanding the nature of these changes is essential for management decision-making. This study sought to apply the Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Normalized Difference Built-up Index (NDBI) - Enhanced Normalized Difference Built-up Index (NDBI-ENDBI) indices to assess the changes in vegetation, water bodies, and build-up area, respectively, in the basin between 1978 and 2018. Landsat imageries for 1978, 1988, 1998, 2008, and 2018 with thematic-oriented bands were acquired, pre-processed, and subjected to spectral-based classification techniques in ArcGIS software to compute and generate NDVI, NDWI, and NDBI-ENDBI maps. According to the results, NDVI indicated an intense decreasing trend in the density of vegetated landscapes while NDVI, NDWI, and NDBI all depicted fluctuations in moisture content (in Lake Victoria and its wetlands). The NDBI-ENDBI showed an intense increasing trend in the built-up area expansion. Based on these changes, the study concluded that urban development has been rapidly progressing within the Lake Victoria basin over the years. Intensive and strategic planning that strikes a balance between economic development and environmental conservation is recommended to realize the sustainability of this important watershed.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 1-11"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471421000103/pdfft?md5=bf72c8f9d64fe49a07c938287ea37374&pid=1-s2.0-S2589471421000103-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89612647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Welfare impacts of water security in Kenya: Evidence from the Upper Ewaso Ngiro North Catchment Area","authors":"Simon Ng'ang'a Mwaura ,&nbsp;Isaac Maina Kariuki ,&nbsp;Symon Kiprop ,&nbsp;Augustus Sammy Muluvi ,&nbsp;Boniface Kiteme","doi":"10.1016/j.wsee.2022.01.001","DOIUrl":"10.1016/j.wsee.2022.01.001","url":null,"abstract":"<div><p>Water insecurity is a major concern both in the global and local contexts. The study estimated the sub-catchment water poverty index and the household water security index, on cross-sectional farm household data collected from 652 households randomly selected from eight sub-catchments of the Upper Ewaso Ng’iro North Catchment Area (ENNCA). The impact of water security on household income per adult equivalent and prevalence of waterborne diseases was assessed using ordinary least squares regression and Poisson regression models respectively. Water Poverty Index (WPI) results revealed that Sirimon and Ewaso Narok sub-catchments are faced with acute water stress, while the rest of the sub-catchments are faced with moderate water stress despite being in the sub-catchment area. The results showed that improved water security can offer welfare benefits to households through increments in household income and reduced water-borne disease prevalence. From the findings, therefore, improved water security can offer both economic and health solutions to some of the country's problems including poverty alleviation and reduce the government's budget spending on communicable and non-communicable water-related diseases.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 32-43"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471422000018/pdfft?md5=9681c3aff6d0d826fc1b9abddb1e37e7&pid=1-s2.0-S2589471422000018-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84304562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sources of terrestrial nitrogen and phosphorus mobilization in South and South East Asian coastal ecosystems","authors":"Anup Maharjan ,&nbsp;Peter M. Groffman ,&nbsp;Charles J. Vörösmarty ,&nbsp;Maria Tzortziou ,&nbsp;Xiaojing Tang ,&nbsp;Pamela A. Green","doi":"10.1016/j.wsee.2021.12.002","DOIUrl":"10.1016/j.wsee.2021.12.002","url":null,"abstract":"<div><p>South and Southeast Asia (SSEA) is a socially, economically and ecologically diverse region, with a rapidly growing population and accelerating industrial development, agricultural intensification using manufactured fertilizers, terrestrial landscape change, expansion of water engineering, sewage production and land conversions. Nitrogen and phosphorus are major nutrients that play an essential role in the eutrophication of inland and coastal water bodies. Eutrophic areas, when combined with appropriate coastal ocean physical conditions, can develop into hypoxic zones that result in long-term ecosystem disruption. This study addressed changes in terrestrial nitrogen and phosphorus mobilization associated with land-use transitions, fertilizer use and sewage from 2002 to 2016 in the SSEA region, with a focus on the Mekong and Krishna-Godavari watersheds. Terrestrial mobilization results from the internal production or addition of reactive, soluble and/or plant available forms of nitrogen and phosphorus. To estimate terrestrial mobilization associated with land conversion, published data were mined for estimates of land cover change effects on soil carbon, nitrogen and phosphorus pools. Data on exogenous fertilizer and sewage effluents were also compiled from the literature. From the analysis, it showed that fertilizer input was the largest source of nitrogen and phosphorus in both case study watersheds. Sewage and land conversion were not a significant source of terrestrial phosphorus mobilization in either watershed. All land conversions resulted in declines in soil carbon, ranging from 11% to 38%. Nitrogen increased, on average by 15%, in conversions of agricultural to urban land, but decreased in all other conversions. Phosphorus increased by 89% in wetland to agriculture conversions, but decreased between 2% and 24% for other land conversions. Expansion of agriculture at the expense of forest was the dominant land conversion in the Mekong watershed. Urbanization, at the expense of agriculture and forest, was the dominant land conversion in the Krishna/Godavari watershed. These results suggest that management of nutrient pollution (N and P) in SSEA will need to focus on reducing the use and/or improving the efficiency of fertilizer use along with regular consolidated monitoring in both watersheds.</p></div>","PeriodicalId":101280,"journal":{"name":"Watershed Ecology and the Environment","volume":"4 ","pages":"Pages 12-31"},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589471421000115/pdfft?md5=b05f6ea82cbe9ad5c6b8b111aebef3fc&pid=1-s2.0-S2589471421000115-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89846871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}