In the past decades, two large scale coastal engineering projects have been carried out in the Deep Bay surrounded by Shenzhen City and Hong Kong Special Administrative Region. One project is Shenzhen River channel re...In the past decades, two large scale coastal engineering projects have been carried out in the Deep Bay surrounded by Shenzhen City and Hong Kong Special Administrative Region. One project is Shenzhen River channel regulation and the other is the sea reclamation along the seashore on the Shenzhen side. The two projects are very close to the two national nature reserves, specifically Futian in Shenzhen and Mai Po in Hong Kong, which are important wetland ecosystems worldwide. This paper aims to identify and monitor the mangrove wetland changes with time series of Landsat Thematic Mapper images pre and post to the two engineering projects being launched. Coupled analysis of the image interpretation results and tidal data acquired at the same time in the context of the two works reveals that the mangrove wetland area has increased from year 1989 to 1994, and has changed little from year 1994 to 2002. Binary coding is applied to reveal the distribution image of mangrove at each phase, and the coding image shows that the construction of the two coastal engineering projects has caused frequent changes in mangrove spatial distribution. The study also shows that the change is not significant regarding to the precision of the method and the natural evolution of mangrove wetland, and the projects do not cause apparently influences upon the two national mangrove conservation zones at least for the research time period.展开更多
Based on Landsat TM images in 2005 and urban planning data of 2005-2020 in Hangzhou Bay Industrial Belt, this paper studied the potential risk of the planned urban construction land extension to the wetlands by employ...Based on Landsat TM images in 2005 and urban planning data of 2005-2020 in Hangzhou Bay Industrial Belt, this paper studied the potential risk of the planned urban construction land extension to the wetlands by employing a GIS spatial analysis method. The results show that： （1） The wetland resources are widely distributed and diverse, with a proximal distribution to present urban construction lands spatially. （2） From 2005 to 2020, the urban construction lands will expand vastly and rapidly, and will take over large areas of wetlands that are mostly the ponds and the aquiculture water areas in the reclamation areas of Hangzhou Bay south coast. Moreover, this change will be spatially uneven obviously, e.g., the most serious recessions of the wetlands are concentrated in Ningbo city, Hangzhou city and Cixi city. （3） Overall, the potential risk to wetlands is very high, and will keep increasing with the trend of urbanization. （4） The quantity and spatial pattern of the planning urban construction land have substantial impacts on the wetland loss. Therefore, some policies and regulations are suggested to coordinate the relationship between urban economic development and wetland resource protection such as adjusting the construction land planning, compensating for wetland occupation as well as constructing wetland parks.展开更多
In order to investigate distributions of heavy metal pollution in Quanzhou Bay wetland, the total concentration and chemical partitioning of a number of heavy metals （Cu, Zn, Cd, Pb, Cr, Hg） in sediments of three sa...In order to investigate distributions of heavy metal pollution in Quanzhou Bay wetland, the total concentration and chemical partitioning of a number of heavy metals （Cu, Zn, Cd, Pb, Cr, Hg） in sediments of three sampling sites of Quanzhou Bay wetland and their availability to Suaeda australis were analyzed. The Geoaccumulation Index （Igeo） values reveal that the sediments of three sampling sites may all be considered as moderately contaminated for Pb and Zn, and all sediments might be strongly contaminated with cadmium. The partitioning analyses revealed the measured heavy metals in three sites are bound to the exchangeable fraction at lower concentrations. The measured metals in a considerable amount are bound to the reducible and oxidizable fractions, and a high proportion of the measured heavy metals were distributed in the residual fraction in the sediment samples. The concentrations of Cd in each chemical phase extracted from the sediments are above natural global background levels and should be further investigated because of its toxicity. Suaeda australis has different accumulation abilities for the measured heavy metals. For the root and stem, the bioaccumulation ability assessed by bioaccumulation factor （BAF） for the measured heavy metals follows the decreasing order as： Cu〉Cr〉 Zn〉Cd, Pb, Hg. In the leaf, stronger bioaccumulation ability for Hg is exhibited. The heavy metal concentrations in Suaeda australis roots have positive correlations with their available fractions, while the exchangeable fraction of Cu and Cd might have be more important to both mature plant roots and seedling roots uptake than other fractions; as for Cr, the oxidizable fraction might make a greater contribution to the plant root uptake; as for Zn, the reducible fraction might make so contribution ; and for Pb, the oxidizable fraction might make a significant contribution to the mature plant root uptake, however, the exchangeable fraction might have a significant contribution to the seedling root uptake.展开更多
Phosphorus (P) released and transported from wetlands affects wetland ecosystems and surrounding water systems. Sediment samples from the Pelham Bay wetlands in the Bronx, NY, have been collected and analyzed. Analysi...Phosphorus (P) released and transported from wetlands affects wetland ecosystems and surrounding water systems. Sediment samples from the Pelham Bay wetlands in the Bronx, NY, have been collected and analyzed. Analysis of the sorption characteristics, P compound identification and P mineralization, showed significant correlations between the sorption maximum (Smax) and Ox-Fe (r = 0.894), ash-TP and HCl-Ca (r = 0.94), ash-TP and TOC (r = 0.96), as well as TOC vs HCl-Ca (r = 0.93). These results indicate that mineral content affects the OP content and the sorption process. P sorption maxima Smax ranged from 70.4 to 1667 mg/Kg, and the equilibrium P concentration EPC<sub>0</sub> ranged from 0.09 to 0.2 mg/L. The high Smax in most of the sites, fairly high EPC<sub>0</sub> and high percentages of Pr (>96%), indicate substantial amounts of P could be bioavailable for plant uptake in the water column under changing hydro-climatic conditions. Dominant P compounds are dihydroxyacetone phosphate (DHAP), phosphoenolpyruvates (PEP), inosine monophosphate (IMP), glucose-6-phosphate (G6P), nucleoside monophosphates (NMP), glycerophosphate (GlyP), polynucleotides (PolyN), and pyrophosphates (Pyrop). The active P pool could maintain substantial P bioavailability and potentially cause eutrophication. The mineralization of 7, 15 and 30 days in laboratory experiments indicates a decrease of NaHCO<sub>3</sub> and HCl, and an increase of NaOH.展开更多
In order to understand the spatial distribution of heavy metals in coastal wetlands,Tamarix chinensis wetlands on the south bank of Bohai Bay were selected as the research object.The content of Cr,Mn,Ni,Zn and Cu in s...In order to understand the spatial distribution of heavy metals in coastal wetlands,Tamarix chinensis wetlands on the south bank of Bohai Bay were selected as the research object.The content of Cr,Mn,Ni,Zn and Cu in soil was determined by sampling method in April 2018.The spatial distribution characteristics of heavy metals and causes were studied.The results showed that except for Cr,Ni and Zn,the content of other heavy metals in this area did not exceed the background value of soil environment in Shandong Province.The study area was slightly polluted by these three heavy metals.In the vertical direction,the content of Cr,Mn,Cu and Ni followed the law of surface layer>middle layer>bottom layer,while the content of Zn was higher in the bottom layer,which needed to be further studied.In the horizontal direction,the content of the five heavy metals was not significantly different according to the distance from the coastline.There was no significant difference in the content of heavy metals between rhizosphere soil and non-rhizosphere soil.There was a significant correlation between the content of heavy metal elements,except Mn,the content of heavy metals was significantly correlated with the content of soil organic matter.The content of some heavy metals was significantly correlated with the content of available phosphorus and ammonium nitrogen.展开更多
文摘In the past decades, two large scale coastal engineering projects have been carried out in the Deep Bay surrounded by Shenzhen City and Hong Kong Special Administrative Region. One project is Shenzhen River channel regulation and the other is the sea reclamation along the seashore on the Shenzhen side. The two projects are very close to the two national nature reserves, specifically Futian in Shenzhen and Mai Po in Hong Kong, which are important wetland ecosystems worldwide. This paper aims to identify and monitor the mangrove wetland changes with time series of Landsat Thematic Mapper images pre and post to the two engineering projects being launched. Coupled analysis of the image interpretation results and tidal data acquired at the same time in the context of the two works reveals that the mangrove wetland area has increased from year 1989 to 1994, and has changed little from year 1994 to 2002. Binary coding is applied to reveal the distribution image of mangrove at each phase, and the coding image shows that the construction of the two coastal engineering projects has caused frequent changes in mangrove spatial distribution. The study also shows that the change is not significant regarding to the precision of the method and the natural evolution of mangrove wetland, and the projects do not cause apparently influences upon the two national mangrove conservation zones at least for the research time period.
基金Key Project of Zhejiang Provincial Science and Technology Programs, No.2005C23059 National Key Technology R＆D Program of China, No.2006BAJ11B03 National Natural Science Foundation of China, No.40701177 The authors thank Prof. Liu Xinguo from Zhejiang University for his modification of language.
文摘Based on Landsat TM images in 2005 and urban planning data of 2005-2020 in Hangzhou Bay Industrial Belt, this paper studied the potential risk of the planned urban construction land extension to the wetlands by employing a GIS spatial analysis method. The results show that： （1） The wetland resources are widely distributed and diverse, with a proximal distribution to present urban construction lands spatially. （2） From 2005 to 2020, the urban construction lands will expand vastly and rapidly, and will take over large areas of wetlands that are mostly the ponds and the aquiculture water areas in the reclamation areas of Hangzhou Bay south coast. Moreover, this change will be spatially uneven obviously, e.g., the most serious recessions of the wetlands are concentrated in Ningbo city, Hangzhou city and Cixi city. （3） Overall, the potential risk to wetlands is very high, and will keep increasing with the trend of urbanization. （4） The quantity and spatial pattern of the planning urban construction land have substantial impacts on the wetland loss. Therefore, some policies and regulations are suggested to coordinate the relationship between urban economic development and wetland resource protection such as adjusting the construction land planning, compensating for wetland occupation as well as constructing wetland parks.
文摘In order to investigate distributions of heavy metal pollution in Quanzhou Bay wetland, the total concentration and chemical partitioning of a number of heavy metals （Cu, Zn, Cd, Pb, Cr, Hg） in sediments of three sampling sites of Quanzhou Bay wetland and their availability to Suaeda australis were analyzed. The Geoaccumulation Index （Igeo） values reveal that the sediments of three sampling sites may all be considered as moderately contaminated for Pb and Zn, and all sediments might be strongly contaminated with cadmium. The partitioning analyses revealed the measured heavy metals in three sites are bound to the exchangeable fraction at lower concentrations. The measured metals in a considerable amount are bound to the reducible and oxidizable fractions, and a high proportion of the measured heavy metals were distributed in the residual fraction in the sediment samples. The concentrations of Cd in each chemical phase extracted from the sediments are above natural global background levels and should be further investigated because of its toxicity. Suaeda australis has different accumulation abilities for the measured heavy metals. For the root and stem, the bioaccumulation ability assessed by bioaccumulation factor （BAF） for the measured heavy metals follows the decreasing order as： Cu〉Cr〉 Zn〉Cd, Pb, Hg. In the leaf, stronger bioaccumulation ability for Hg is exhibited. The heavy metal concentrations in Suaeda australis roots have positive correlations with their available fractions, while the exchangeable fraction of Cu and Cd might have be more important to both mature plant roots and seedling roots uptake than other fractions; as for Cr, the oxidizable fraction might make a greater contribution to the plant root uptake; as for Zn, the reducible fraction might make so contribution ; and for Pb, the oxidizable fraction might make a significant contribution to the mature plant root uptake, however, the exchangeable fraction might have a significant contribution to the seedling root uptake.
文摘Phosphorus (P) released and transported from wetlands affects wetland ecosystems and surrounding water systems. Sediment samples from the Pelham Bay wetlands in the Bronx, NY, have been collected and analyzed. Analysis of the sorption characteristics, P compound identification and P mineralization, showed significant correlations between the sorption maximum (Smax) and Ox-Fe (r = 0.894), ash-TP and HCl-Ca (r = 0.94), ash-TP and TOC (r = 0.96), as well as TOC vs HCl-Ca (r = 0.93). These results indicate that mineral content affects the OP content and the sorption process. P sorption maxima Smax ranged from 70.4 to 1667 mg/Kg, and the equilibrium P concentration EPC<sub>0</sub> ranged from 0.09 to 0.2 mg/L. The high Smax in most of the sites, fairly high EPC<sub>0</sub> and high percentages of Pr (>96%), indicate substantial amounts of P could be bioavailable for plant uptake in the water column under changing hydro-climatic conditions. Dominant P compounds are dihydroxyacetone phosphate (DHAP), phosphoenolpyruvates (PEP), inosine monophosphate (IMP), glucose-6-phosphate (G6P), nucleoside monophosphates (NMP), glycerophosphate (GlyP), polynucleotides (PolyN), and pyrophosphates (Pyrop). The active P pool could maintain substantial P bioavailability and potentially cause eutrophication. The mineralization of 7, 15 and 30 days in laboratory experiments indicates a decrease of NaHCO<sub>3</sub> and HCl, and an increase of NaOH.
基金Scientific Research Foundation of Binzhou University(BZXYLG 1925).
文摘In order to understand the spatial distribution of heavy metals in coastal wetlands,Tamarix chinensis wetlands on the south bank of Bohai Bay were selected as the research object.The content of Cr,Mn,Ni,Zn and Cu in soil was determined by sampling method in April 2018.The spatial distribution characteristics of heavy metals and causes were studied.The results showed that except for Cr,Ni and Zn,the content of other heavy metals in this area did not exceed the background value of soil environment in Shandong Province.The study area was slightly polluted by these three heavy metals.In the vertical direction,the content of Cr,Mn,Cu and Ni followed the law of surface layer>middle layer>bottom layer,while the content of Zn was higher in the bottom layer,which needed to be further studied.In the horizontal direction,the content of the five heavy metals was not significantly different according to the distance from the coastline.There was no significant difference in the content of heavy metals between rhizosphere soil and non-rhizosphere soil.There was a significant correlation between the content of heavy metal elements,except Mn,the content of heavy metals was significantly correlated with the content of soil organic matter.The content of some heavy metals was significantly correlated with the content of available phosphorus and ammonium nitrogen.
