This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current ...This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current systems by analyzing the thermal infrared imagery with the sediment imagery, which is acquired by correlating the atmosphere corrected AVHRR imagery with in-situ suspended sediment data. The coastal current systems affecting the sediment dispersal mainly include: the Taiwan Warm Current (TWC), the Huanghai Sea Mixed Water (HSMW), North Jiangsu near-shore current, and Zhejiang near-shore current etc. In winter, the current systems are stable. Their distribution affects the sediment from north Jiangsu expanding toward the Changjiang estuary in some degree .The front between Zhejiang coastal current and TWC blocks the expanding of sediment toward the sea. In the flood season, apart from the limitation by coastal current systems, the spatial and temporal distribution of suspended sediment is also affected by the runoff, which shows as the jet stream and fresh water. Spring and autumn are the transitional periods of the forming of expanding patterns of flood season and winter respectively. In addition, the re-suspended sediment caused by the wind wave may make the expanding range of near-shore sediment larger.展开更多
MANDELBROT enunciated the uncertainty of the length of a coastline in his paper"How long is the coastline of Britain?"published in "Science" in 1967. The fractal concept was presented for the first...MANDELBROT enunciated the uncertainty of the length of a coastline in his paper"How long is the coastline of Britain?"published in "Science" in 1967. The fractal concept was presented for the first time in that paper and has been applied to many fields ever since. According to the fractal theory and conditions of fractal research of coastline,the controls of faults and biologic function on the fractal character of coastline are preliminarily discussed on the basis of GIS in this paper . Finally,some significant conclusions are drawn:1)the faults control the basic trends of coastlines of two study areas;2)the fractal dimension of coastline of Taiwan is smaller than that of Changle-Lufeng,because the faults of Taiwan more intensely control the trend and fractal dimension of the coastline;3)the larger the fractal dimension of the faults or the major faults,the more the controlling effect of them on the trend and fractal dimension of coastline; 4)the larger fractal dimension of the coastline of Changle-Lufeng indicates that the biologic function intensely shapes the coastline. In a word,the controls of faults and biologic function on the fractal character of coastline are discussed with a case study of China in this paper,it can be seen that faults and biologic function both have influence over the trend and fractal dimension of coastline,the fractal mechanism of coastline of two study areas may be so.展开更多
Acid sulfate soils (ASS) contain considerable amounts of reduced sulfur compounds (mainly pyrite) which produce sulfuric acid upon their oxidation. ASS-derived environmental degradation widely occurs in the coastal lo...Acid sulfate soils (ASS) contain considerable amounts of reduced sulfur compounds (mainly pyrite) which produce sulfuric acid upon their oxidation. ASS-derived environmental degradation widely occurs in the coastal lowlands around the world, especially in the tropical and subtropical areas. The presence of ASS in the South China has been recognized but their distribution may be largely underestimated because the soil survey data concerning ASS are based on unreliable methods and techniques. ASS in the South China have been traditionally used for rice cultivation and this practice has been proved sustainable if appropriate improvement measures are adopted. Recently, the rapid economic growth in the region has resulted in intensified coastal development which frequently involves activities that may disturb ASS. Construction of roads, foundations and aquaculture ponds may cause the exposure of ASS to air and bring about severe environmental acidification. There is currently insufficient awareness of the problems among the researchers, policy-makers and land managers in the South China. More atteation must be paid to the possible ASSderived environmental degradation in order to ensure a sustainable development of the coastal lowlands in the South China region.展开更多
To investigate the mechanism of secondary circulations in rip current systems, and to explore the relationship between wave conditions and secondary circulation intensity, a series of numerical experiments is performe...To investigate the mechanism of secondary circulations in rip current systems, and to explore the relationship between wave conditions and secondary circulation intensity, a series of numerical experiments is performed using coupled nearshore wave model and circulation model. In these experiments, the rip currents and secondary circulations generated above barred beaches with rip channels are simulated. A comparison experiment is conducted to investigate the formation and hydrodynamics of the secondary circulations. Model results indicate that the secondary circulations consist of alongshore flows driven by wave set-up near the shoreline, part of the feeder currents driven by the wave set-up over the bars, and onshore flows at the end of the rip channel driven by wave breaking and convection. The existence of the secondary circulation barely affects the rip current, but narrows and intensifies the feeder currents. Three groups of experiments of varying incident wave conditions are performed to investigate the relationship between wave conditions and secondary circulation intensity. The velocity of the alongshore flow of the secondary circulation is sensitive to the variation of the incident wave height and water depth. It is also found that the alongshore flow intensity is in direct proportion to the alongshore variation of the wave height gradient between the bars and the shoreline.展开更多
We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in thc Yellow Sea in the summer 2000. The four stations were characterize...We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in thc Yellow Sea in the summer 2000. The four stations were characterized by different levels of pollution. The ciliate communities consisted primarily of tintinnids and aloricate ciliates that were 〈30 um. A total of 78 species were classified: 55 species at Station 2, 51 species each at Stations l and 4, and 47 species at Station 3. The mean number of species at each site was 29.2±2.0 (Station 1), 28.5±2.9 (Station 2), 27.8±1.7 (Station 3), and 24.5±2.3 (Station 4). The abundance was highly variable: 19 331±11 187 ind./L at Station 1, 7 960±5 639 ind./L at Station 2, 29 015±12 999 ind./L at Station 3, and 8 190±4 658 ind./L at Station 4. Our results suggest that neither the simple chemical analysis (e.g. chemical oxygen demand, dissolved inorganic nitrogen, and phosphate) nor the eutrophication/pollution index adequately described the water quality at the four stations. The same was true of the number of species and their abundance, both of which had no correlation with the chemical indices. In contrast, Margalef's diversity index values (3.12 at Station 2, 2.89 at Station 1, and 2.64 at Stations 3 and 4) generally discriminated the water quality status of the four stations. The difference in water quality among the stations was strongly supported by the pattern of species richness (i.e. the total number of species) of ciliates at each station. Our evaluation was consistent with the results of long-term water quality monitoring at the four stations. With increasing eutrophication, we observed also a compositional and functional shift in the ciliate assemblages from algivorous oligotrich/choreotrich to nonselective-omnivorous gymnostomatids to bacterivorous-detrivorous scuticociliatids. Thus, eiliates may be used to indicate the coastal water quality status of a given site.展开更多
45 and 50 composite soil samples were collected, respectively, from twoagricultural fields, that were enclosed and reclaimed from coastal tidal-flat areas in 1996 and 1984respectively, in Shangyu of Zhejiang Province,...45 and 50 composite soil samples were collected, respectively, from twoagricultural fields, that were enclosed and reclaimed from coastal tidal-flat areas in 1996 and 1984respectively, in Shangyu of Zhejiang Province, China, to investigate the physico-chemicalproperties and the hyperspectral characteristics of the saline soils and to make an assessment ontheir relationships. The reflectance spectra of saline soils were measured using a spectroradiometerin laboratory. The mean spectral curves of the saline soils from the two sites different inreclamation year showed that the saline soil taken from the recently reclaimed land with highersalinity demonstrated a lower reflectance intensity in the spectral region from about 550 nm to 2300nm. In addition, nine absorption bands, i.e., 488 nm, 530 nm, 670 nm, 880 nm, 940 nm, 1400 nm, 1900nm, 2 200 nm and 2 300 nm, were chosen as the spectral bands to investigate the relationshipsbetween soil physico-chemical properties by means of Pearson correlation analysis. Finally, thefirst two principal components were calculated from nine absorption bands and used to discriminatethe saline soil samples taken from two sampled fields. The results indicate that it is feasible todetect physico-chemical properties of saline soils from fields reclaimed for varying time periods onthe basis of the hyperspectral data.展开更多
A poorly-described marine planktonic ciliate, Tintinnopsis brasiliensis Kofoid & Campbell, 1929, collected from the Taiping Cape of Qingdao, China, was morphologically investigated based on permanent preparation afte...A poorly-described marine planktonic ciliate, Tintinnopsis brasiliensis Kofoid & Campbell, 1929, collected from the Taiping Cape of Qingdao, China, was morphologically investigated based on permanent preparation after protargol impregnation and was compared with other related congeners. According to the infraciliature, three ciliary groups can be recognized, which reveals a very stable structure among specimens and denotes that the pattern of infraciliature is, apart from the features of the lorica, a highly reliable criterion for species identification.展开更多
Shuangtaizi estuarine wetland along the Bohai Sea coast,the biggest bulrush wetland in the world,has been listed in 'The Record of Important International Wetland Conservation District'. Taking the year of 2 0...Shuangtaizi estuarine wetland along the Bohai Sea coast,the biggest bulrush wetland in the world,has been listed in 'The Record of Important International Wetland Conservation District'. Taking the year of 2 000 as an example,the minimum,the most suitable and the maximum ecological water requirement of Shuangtaizi estuarine wetland are calculated in this paper based on both ecological theory and Geological Information System technology. In addition,the remote sensing technique is adopted in the data acquisition process. Moreover,the total water requirement and the unit area water requirement for different wetland types are obtained. The result is very important for water resources planning,ecological conservation and regional agriculture structure adjustment in Shuangtaizi. Meanwhile,this study can serve as a useful example for calculating the ecological water requirement in other similar estuarine wetlands.展开更多
The Jimo coast encompasses an area of 2157 km^2, and the ecosystem is valuable both socially and economically with regional fisheries substantially contributing to the value. A mass-balanced trophic model consisting o...The Jimo coast encompasses an area of 2157 km^2, and the ecosystem is valuable both socially and economically with regional fisheries substantially contributing to the value. A mass-balanced trophic model consisting of 15 functional ecological groups was developed for the coastal ecosystem using the Ecopath model in Ecopath with Ecosim(Ew E) software(version 6.4.3). The results of the model simulations indicated that the trophic levels of the functional groups varied between 1.0 and 3.76, and the total production of the system was estimated to be 5112.733 t km^(-2) yr^(-1) with a total energy transfer efficiency of 17.6%. The proportion of the total flow originating from detritus was estimated to be 48%, whereas that from primary producers was 52%, indicating that the grazing food chain dominated the energy flow. The ratio of total primary productivity to total respiration in the system was 3.78, and the connectivity index was 0.4. The fin cycling index and the mean path length of the energy flow were 4.92% and 2.57%, respectively, which indicated that the ecosystem exhibits relatively low maturity and stability. The mixed trophic impact(MTI) procedure suggested that the ecological groups at lower trophic levels dominated the feeding dynamics in the Jimo coastal ecosystem. Overfishing is thought to be the primary reason for the degeneration of the Jimo coastal ecosystem, resulting in a decline in the abundance of pelagic and demersal fish species and a subsequent shift to the predominance of lower-trophic-level functional groups. Finally, we offered some recommendations for improving current fishery management practices.展开更多
A total of 43 sediment samples were collected at Kemaman coast, Terengganu, by using Smith Mclntyre grab. These sediments were analyzed to determine the grain size, sediment texture and metallic trace elements. Lazer ...A total of 43 sediment samples were collected at Kemaman coast, Terengganu, by using Smith Mclntyre grab. These sediments were analyzed to determine the grain size, sediment texture and metallic trace elements. Lazer diffraction method using PSA (particle size analyzer) was used to determine the grain size and sediment texture. Teflon bomb was used to digest the sediments for metallic trace elements concentration. Results showed that the study area was dominated with sand particles (60.5%) followed by loamy sand (20.9%), sandy clay (16.3%) and silt loam (2.3%). On the other hand, the average concentrations of each metallic trace elements were 0.12 pg/g for Cd; 36.6 lag/g for Cr; 9.51 pg/g for Cu; 11.6 ~tg/g for N: 41.5 ~tg/g for Zn and 29.3/ag/g for Pb. Based on the results, it was found out that coarse sediments showed lower levels of metallic trace elements and higher levels in fine sediments. In addition, enrichment factor was calculated to assess the pollution status of the study area. Based on the calculation, the enrichment of metallic trace elements ranked in the following order: Pb 〉 Cd 〉 Zn 〉 Cu 〉 Ni 〉 Cr. The significant enrichment of Pb and moderate enrichment of Cd and Zn indicated that there are anthropogenic inputs while the rest of the metals can be considered from natural sources although there are effects of anthropogenic inputs in some sampling location.展开更多
Peatlands represent one of the most important economic resources and abandoned peatlands after mining can be considered as ecological resources by re-vegetation restoration or management. However, some environmental p...Peatlands represent one of the most important economic resources and abandoned peatlands after mining can be considered as ecological resources by re-vegetation restoration or management. However, some environmental problems like particles from peatlands and their effects in the water system have to be characterized. Since centuries, artificial drainage has been a current practice for the mining of peatlands. Mainly mined for horticultural purpose, New Brunswick's peatlands--predominantly located in the eastern of the province--cover about 140,000 ha. At the downstream end of the drainage system, the water from peatlands flow into sedimentation basins. Drainage waters are often laden with solid particles. Once they have flowed through the ponds to allow sediment settling, the water is released into the water system. This paper describes the spatio-temporal evolution of suspended solids from 12 New Brunswick drained peatlands. The studied sites were characterized by some heterogeneity in the concentration of suspended solids. This study also provides knowledge on the suspended solids amount that can be released by drained peatlands, and it proposes a function to estimate the concentration of suspended solids by using climate variables; and identifies some potential ecological risks.展开更多
Nha Trang Bay is famous not only because of its beauty, but also of the biodiversity values, especially coral reefs. Thus, the sea water quality monitoring systems are necessary for effective and available managements...Nha Trang Bay is famous not only because of its beauty, but also of the biodiversity values, especially coral reefs. Thus, the sea water quality monitoring systems are necessary for effective and available managements to protect the ecosystems and for sustainable development. There have been several monitoring systems here but they have been done separately and unconnectedly. This research was done to take an overview and access the status and changes of water quality from 2007-2014. The data obtained rainy seasons over the years showed a quite good environment here. The environment changes were also monitored and there were some changes between seasons and over years, decreasing, increasing, or unobvious trends. However, the difference was not so much; and there was not the sign of environmental degradation in the bay from 2007 to 2014. Besides, the stoichiometric nutrients limitations were initially assessed. Since Si ratios here were always higher compared to N and P, there was not increased potential for non-diatom algal blooms. Together with the recorded nutrients concentration data, it can be said that there was no evidence of eutrophication in the bay. Although there was partial contamination of some parameters at few moments, the sea water quality of Nha Trang bay was still in a good condition (according to Vietnamese and ASEAN criteria).展开更多
Based on remote sensing and GIS techniques, land use maps in 2000, 2005 and 2010 in China′s coastal zone were produced, and structural raster data of land use were further generated to calculate land use intensity co...Based on remote sensing and GIS techniques, land use maps in 2000, 2005 and 2010 in China′s coastal zone were produced, and structural raster data of land use were further generated to calculate land use intensity comprehensive index(LUICI) for analyzing land use spatial-temporal characteristics at 1 km scale. Results show that: 1) from the perspective of spatial patterns of landforms at a macro scale, there is a significant difference in land use intensity between the north and the south of China′s coastal zone. Hotspots of changes mainly concentrated in metropolitan areas, estuaries and coastal wetlands; 2) elevation is an important factor that controlling land use spatial patterns at local scale. Land use intensity is much higher within areas below the elevation of 400 m and it decreased significantly as the elevation increasing; 3) there is a significant land-ocean gradient for land use intensity, which is low in island and near-shore areas, but high in the regions that 4–30 km far away the coastline because of much intensive human activities; however, in recent decades land use intensity had been promoted significantly in low near-shore area due to extensive sea reclamations; 4) significant differences of land use intensity were also found among provincial administrative units. A rising trend of land use intensity was found in provincial-level administrative units from 2000 to 2010. To sum up, elevation, land-ocean gradient, socio-economic status and policy are all influencing factors to the spatial patterns and temporal variations of land use intensity in China′s coastal zone.展开更多
In early winter it is usual, in cold regions, that ice features approach offshore structures, like offshore platforms, impacting them, in a slow process of constant deformation build up. Interaction follows, in many c...In early winter it is usual, in cold regions, that ice features approach offshore structures, like offshore platforms, impacting them, in a slow process of constant deformation build up. Interaction follows, in many cases, up to the point where ice-failure caused by bending fracture takes place. This supposes very large contact forces that the structure has to resist. Therefore, quantification of these efforts is of vital importance to the structural design of platforms. In several designs, these platforms are constructed with inclined walls so as to cause ice to fail in a flex-compression mode. In such a case the ice feature is analyzed as a beam constituted of a linear elastic material in brittle state with constant ice thickness. The simplification renders the problem solvable in a close form. However, this hypothesis goes against field observations. Marine currents action, wind and the sequence of contacts among features lead to thickness variations. Here this factor is addressed in the construction of a model, for harmonic forms of variation of thickness profile, and the accompanying curvature variations, whose solution determines field variables used to address the failure question. Due to the deformation dependency of the loading, a numerical scheme for the two-point boundary value problem in the semi-infinite space is developed. Failure pressures are computed based on a Rankine locus of failure. Variations of the order of 20% in the failure loads, as compared to the uniform beam model, are observed.展开更多
The aim of the study is to monitor and assess landslide hazards by remote sensing data processing and GIS (Geographic Information Service) spatial analysis. Idukki district, the western Ghats of India was chosen as ...The aim of the study is to monitor and assess landslide hazards by remote sensing data processing and GIS (Geographic Information Service) spatial analysis. Idukki district, the western Ghats of India was chosen as test area, because of frequent destructive mass wasting processes. Western Ghats is a prominent orographic feature that runs parallel to the south west coast of India. Predicting landslide hazard on a regional scale, namely the assessment of actual and potential mass movement over large area is carried out using Remote Sensing and GIS. A numerical weightage to the causative factors of slope instability such as slope, relative relief, aspect, curvature, drainage density, drainage frequency, land use, road buffer and drainage buffer are assigned as per earlier workers for the purpose of landslide susceptibility zonation. A high degree of match is found between observed and predicted landslide hazard by the procedure employed in the study.展开更多
The proliferation of urban development with concentration in population and human-environment interaction has intensified around urban environments. This has resulted in the degradation of urban environments, overuse ...The proliferation of urban development with concentration in population and human-environment interaction has intensified around urban environments. This has resulted in the degradation of urban environments, overuse of natural resources and widespread pollution of ecosystems, The patterns of design initiatives continue to follow unsustainable path with impacts on stream ecosystems. Accordingly, the paper adopts geospatial information systems and sustainability principles for the identification and sequential mapping of stressors impeding natural systems in Southern Mississippi. The results not only reveal that the study area experienced some significant changes in its watershed environments, but the stream habitat ecosystem remains under stress. The recommendations for mitigating the problems range from policy considerations to the adoption of ecosystem approach.展开更多
The oceans are the largest carbon pools on Earth, and play the role of a "buffer" in climate change. Blue carbon, the carbon(mainly organic carbon) captured by marine ecosystems, is one of the important mech...The oceans are the largest carbon pools on Earth, and play the role of a "buffer" in climate change. Blue carbon, the carbon(mainly organic carbon) captured by marine ecosystems, is one of the important mechanisms of marine carbon storage.Blue carbon was initially recognized only in the form of visible coastal plant carbon sequestration. In fact, microorganisms(phytoplankton, bacteria, archaea, viruses, and protozoa), which did not receive much attention in the past, account for more than 90% of the total marine biomass and are the main contributors to blue carbon. Chinese coastal seas, equivalent to 1/3 of China's total land area, have a huge carbon sink potential needing urgently research and development. In this paper, we focus on the processes and mechanisms of coastal ocean's carbon sequestration and the approaches for increasing that sequestration. We discuss the structures of coastal ecosystems, the processes of carbon cycle, and the mechanisms of carbon sequestration. Using the evolution of coastal ocean's carbon sinks in sedimentary records over geologic times, we also discuss the possible effects of natural processes and anthropogenic activities on marine carbon sinks. Finally, we discuss the prospect of using carbon sequestration engineering for increasing coastal ocean's carbon storage capacity.展开更多
Coastal erosion is currently a major problem along the southern coast of Chongming Island, Shanghai. To enhance the erosion protection ability of coastal shelterbelts, two woody tree species, Taxodium ascendens and Sa...Coastal erosion is currently a major problem along the southern coast of Chongming Island, Shanghai. To enhance the erosion protection ability of coastal shelterbelts, two woody tree species, Taxodium ascendens and Salix babylonica, were planted separately into Phragmites australis + Scirpus mariqueter communities in 2006. Two years later, we investigated whether either of these experiments reduced erosion and increased stability in the native herbaceous plant community. We also examined soil stability and root length density under T. aseendens added, S. babylonica added and native herbaceous vegetation conditions along an intertidal gradient from the soil surface to a depth of 40 cm in each experiment, thus to determine the capacity of T. ascendens and S. babylonica to contribute to shoreline stabilization. Topsoil under the native vegetation had greater stability at the middle and higher intertidal zones because its soil stability index and root length density were significantly higher than in the T. ascendens or S. babylonica planted communities. The effect of T. ascendens on soil stability was not generally better than that of the native vegetation. Only at the 20-30 cm soil depth of the middle intertidal zone and in the 10-20 cm layer of the higher intertidal zone the soil stability index and root length densities under the T. ascendens added condition were significantly higher (P 〈 0.05) than those of the native vegetation. The S. babylonica planted soil had greater stability in the deeper soil layer than the soil under either the native vegetation or the T. ascendens added condition, and its soil stability index and root length density were significant higher (P 〈 0.05) than those of other vegetation conditions at the 30 40 cm soil depth for the lower intertidal zone and at the 20-40 cm layer for middle and higher intertidal zones.展开更多
The shoreline is one of the rapidly changing landforms in coastal areas. They are the key element in coastal GIS and provide the most information on coastal land form dynamics. Therefore, accurate detection and freque...The shoreline is one of the rapidly changing landforms in coastal areas. They are the key element in coastal GIS and provide the most information on coastal land form dynamics. Therefore, accurate detection and frequent monitoring of shorelines is very essential to understand the coastal processes and dynamics of various coastal features. The present study is to investigate the shoreline changes along the coast between Kanyakumari and Tuticorin of south India (where hydrodynamic and morphologic changes occur continuously after the December 2004 tsunami) by using Digital Shoreline Analysis System (DSAS), an extension of ArcGIS. Multidate 1RS and Landsat Satellite data (1999, 2001, 2003, 2005, 2007, and 2009) are used to extract the shorelines. The data is processed by using the ERDAS IMAGINE 9.1 software and analyzed by ArcGIS 9.2 workstation. The rates of shoreline changes are estimated by three statistical methods, namely, End Point Rate (EPR), Linear Regression Rate (LRR), and Least Median of Squares (LMS) by using DSAS. The study reveals that most of the study area has undergoing erosion. Both natural and anthropogenic processes along the coast modify the shoreline configuration and control the erosion and accretion of the coastal zones. The coastal zones along the estuary have experienced accretion due to the littoral processes. The zones with headlands have more eroded than other zones along the study area. The study also shows that the coastal zones where sand is mined have relatively more rate of erosion than that of the other zones. Improper and unsustainable sand mining may also lead to severe erosion problem along this area. The shoreline change rates are altered by various geological processes along the coast. Thus, the present study implies that proper beach filling and nourishment projects should be made in the study area to save from hazards. It also indicates the advantage and suitability of DSAS to assess the shoreline changes compared with the traditional manual shoreline change analysis and promising its applications for coastal zone management in other regions.展开更多
文摘This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current systems by analyzing the thermal infrared imagery with the sediment imagery, which is acquired by correlating the atmosphere corrected AVHRR imagery with in-situ suspended sediment data. The coastal current systems affecting the sediment dispersal mainly include: the Taiwan Warm Current (TWC), the Huanghai Sea Mixed Water (HSMW), North Jiangsu near-shore current, and Zhejiang near-shore current etc. In winter, the current systems are stable. Their distribution affects the sediment from north Jiangsu expanding toward the Changjiang estuary in some degree .The front between Zhejiang coastal current and TWC blocks the expanding of sediment toward the sea. In the flood season, apart from the limitation by coastal current systems, the spatial and temporal distribution of suspended sediment is also affected by the runoff, which shows as the jet stream and fresh water. Spring and autumn are the transitional periods of the forming of expanding patterns of flood season and winter respectively. In addition, the re-suspended sediment caused by the wind wave may make the expanding range of near-shore sediment larger.
文摘MANDELBROT enunciated the uncertainty of the length of a coastline in his paper"How long is the coastline of Britain?"published in "Science" in 1967. The fractal concept was presented for the first time in that paper and has been applied to many fields ever since. According to the fractal theory and conditions of fractal research of coastline,the controls of faults and biologic function on the fractal character of coastline are preliminarily discussed on the basis of GIS in this paper . Finally,some significant conclusions are drawn:1)the faults control the basic trends of coastlines of two study areas;2)the fractal dimension of coastline of Taiwan is smaller than that of Changle-Lufeng,because the faults of Taiwan more intensely control the trend and fractal dimension of the coastline;3)the larger the fractal dimension of the faults or the major faults,the more the controlling effect of them on the trend and fractal dimension of coastline; 4)the larger fractal dimension of the coastline of Changle-Lufeng indicates that the biologic function intensely shapes the coastline. In a word,the controls of faults and biologic function on the fractal character of coastline are discussed with a case study of China in this paper,it can be seen that faults and biologic function both have influence over the trend and fractal dimension of coastline,the fractal mechanism of coastline of two study areas may be so.
文摘Acid sulfate soils (ASS) contain considerable amounts of reduced sulfur compounds (mainly pyrite) which produce sulfuric acid upon their oxidation. ASS-derived environmental degradation widely occurs in the coastal lowlands around the world, especially in the tropical and subtropical areas. The presence of ASS in the South China has been recognized but their distribution may be largely underestimated because the soil survey data concerning ASS are based on unreliable methods and techniques. ASS in the South China have been traditionally used for rice cultivation and this practice has been proved sustainable if appropriate improvement measures are adopted. Recently, the rapid economic growth in the region has resulted in intensified coastal development which frequently involves activities that may disturb ASS. Construction of roads, foundations and aquaculture ponds may cause the exposure of ASS to air and bring about severe environmental acidification. There is currently insufficient awareness of the problems among the researchers, policy-makers and land managers in the South China. More atteation must be paid to the possible ASSderived environmental degradation in order to ensure a sustainable development of the coastal lowlands in the South China region.
基金supported by China’s Public Science and Technology Research Funds Projects of Ocean (No. 200905013-4)by Ministry of Science and Technology of China (No. 2011BAC03B01)
文摘To investigate the mechanism of secondary circulations in rip current systems, and to explore the relationship between wave conditions and secondary circulation intensity, a series of numerical experiments is performed using coupled nearshore wave model and circulation model. In these experiments, the rip currents and secondary circulations generated above barred beaches with rip channels are simulated. A comparison experiment is conducted to investigate the formation and hydrodynamics of the secondary circulations. Model results indicate that the secondary circulations consist of alongshore flows driven by wave set-up near the shoreline, part of the feeder currents driven by the wave set-up over the bars, and onshore flows at the end of the rip channel driven by wave breaking and convection. The existence of the secondary circulation barely affects the rip current, but narrows and intensifies the feeder currents. Three groups of experiments of varying incident wave conditions are performed to investigate the relationship between wave conditions and secondary circulation intensity. The velocity of the alongshore flow of the secondary circulation is sensitive to the variation of the incident wave height and water depth. It is also found that the alongshore flow intensity is in direct proportion to the alongshore variation of the wave height gradient between the bars and the shoreline.
基金Supported by the Korea Research Foundation Grant to J.K.CHOI (No.KRF-2008-013-C00064)the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX2-YW-417)the National Natural Science Foundation of China (No.40576072,40706047)
文摘We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in thc Yellow Sea in the summer 2000. The four stations were characterized by different levels of pollution. The ciliate communities consisted primarily of tintinnids and aloricate ciliates that were 〈30 um. A total of 78 species were classified: 55 species at Station 2, 51 species each at Stations l and 4, and 47 species at Station 3. The mean number of species at each site was 29.2±2.0 (Station 1), 28.5±2.9 (Station 2), 27.8±1.7 (Station 3), and 24.5±2.3 (Station 4). The abundance was highly variable: 19 331±11 187 ind./L at Station 1, 7 960±5 639 ind./L at Station 2, 29 015±12 999 ind./L at Station 3, and 8 190±4 658 ind./L at Station 4. Our results suggest that neither the simple chemical analysis (e.g. chemical oxygen demand, dissolved inorganic nitrogen, and phosphate) nor the eutrophication/pollution index adequately described the water quality at the four stations. The same was true of the number of species and their abundance, both of which had no correlation with the chemical indices. In contrast, Margalef's diversity index values (3.12 at Station 2, 2.89 at Station 1, and 2.64 at Stations 3 and 4) generally discriminated the water quality status of the four stations. The difference in water quality among the stations was strongly supported by the pattern of species richness (i.e. the total number of species) of ciliates at each station. Our evaluation was consistent with the results of long-term water quality monitoring at the four stations. With increasing eutrophication, we observed also a compositional and functional shift in the ciliate assemblages from algivorous oligotrich/choreotrich to nonselective-omnivorous gymnostomatids to bacterivorous-detrivorous scuticociliatids. Thus, eiliates may be used to indicate the coastal water quality status of a given site.
基金Project supported by the National Natural Foundation of China(No.40001008),by the German Federal Ministry of Education and Research (BMBF)(No.AZ39742),and by the Science and Technology Department of Zhejiang Province(No.001110445).
文摘45 and 50 composite soil samples were collected, respectively, from twoagricultural fields, that were enclosed and reclaimed from coastal tidal-flat areas in 1996 and 1984respectively, in Shangyu of Zhejiang Province, China, to investigate the physico-chemicalproperties and the hyperspectral characteristics of the saline soils and to make an assessment ontheir relationships. The reflectance spectra of saline soils were measured using a spectroradiometerin laboratory. The mean spectral curves of the saline soils from the two sites different inreclamation year showed that the saline soil taken from the recently reclaimed land with highersalinity demonstrated a lower reflectance intensity in the spectral region from about 550 nm to 2300nm. In addition, nine absorption bands, i.e., 488 nm, 530 nm, 670 nm, 880 nm, 940 nm, 1400 nm, 1900nm, 2 200 nm and 2 300 nm, were chosen as the spectral bands to investigate the relationshipsbetween soil physico-chemical properties by means of Pearson correlation analysis. Finally, thefirst two principal components were calculated from nine absorption bands and used to discriminatethe saline soil samples taken from two sampled fields. The results indicate that it is feasible todetect physico-chemical properties of saline soils from fields reclaimed for varying time periods onthe basis of the hyperspectral data.
基金supported by'the Natural Science Foundation of China'(No.40376045)'the National Science Council,R0C'(NSC 89-2611-M-019-007-K2).
文摘A poorly-described marine planktonic ciliate, Tintinnopsis brasiliensis Kofoid & Campbell, 1929, collected from the Taiping Cape of Qingdao, China, was morphologically investigated based on permanent preparation after protargol impregnation and was compared with other related congeners. According to the infraciliature, three ciliary groups can be recognized, which reveals a very stable structure among specimens and denotes that the pattern of infraciliature is, apart from the features of the lorica, a highly reliable criterion for species identification.
基金supported by the Special Doctorate Science Foundation of the Ministry of Education (No. 200601570011)Liaoning Supporting Plan for Excel-lent Talents ([2006]124#)the National Natural Sci-ence Foundation of China (No.50879046).
文摘Shuangtaizi estuarine wetland along the Bohai Sea coast,the biggest bulrush wetland in the world,has been listed in 'The Record of Important International Wetland Conservation District'. Taking the year of 2 000 as an example,the minimum,the most suitable and the maximum ecological water requirement of Shuangtaizi estuarine wetland are calculated in this paper based on both ecological theory and Geological Information System technology. In addition,the remote sensing technique is adopted in the data acquisition process. Moreover,the total water requirement and the unit area water requirement for different wetland types are obtained. The result is very important for water resources planning,ecological conservation and regional agriculture structure adjustment in Shuangtaizi. Meanwhile,this study can serve as a useful example for calculating the ecological water requirement in other similar estuarine wetlands.
基金the financial support provided by the National Social Science Foundation (Grant No.12JJD790032)the Project of the Chinese Ministry of Education (Grant No.13JJD790032)
文摘The Jimo coast encompasses an area of 2157 km^2, and the ecosystem is valuable both socially and economically with regional fisheries substantially contributing to the value. A mass-balanced trophic model consisting of 15 functional ecological groups was developed for the coastal ecosystem using the Ecopath model in Ecopath with Ecosim(Ew E) software(version 6.4.3). The results of the model simulations indicated that the trophic levels of the functional groups varied between 1.0 and 3.76, and the total production of the system was estimated to be 5112.733 t km^(-2) yr^(-1) with a total energy transfer efficiency of 17.6%. The proportion of the total flow originating from detritus was estimated to be 48%, whereas that from primary producers was 52%, indicating that the grazing food chain dominated the energy flow. The ratio of total primary productivity to total respiration in the system was 3.78, and the connectivity index was 0.4. The fin cycling index and the mean path length of the energy flow were 4.92% and 2.57%, respectively, which indicated that the ecosystem exhibits relatively low maturity and stability. The mixed trophic impact(MTI) procedure suggested that the ecological groups at lower trophic levels dominated the feeding dynamics in the Jimo coastal ecosystem. Overfishing is thought to be the primary reason for the degeneration of the Jimo coastal ecosystem, resulting in a decline in the abundance of pelagic and demersal fish species and a subsequent shift to the predominance of lower-trophic-level functional groups. Finally, we offered some recommendations for improving current fishery management practices.
文摘A total of 43 sediment samples were collected at Kemaman coast, Terengganu, by using Smith Mclntyre grab. These sediments were analyzed to determine the grain size, sediment texture and metallic trace elements. Lazer diffraction method using PSA (particle size analyzer) was used to determine the grain size and sediment texture. Teflon bomb was used to digest the sediments for metallic trace elements concentration. Results showed that the study area was dominated with sand particles (60.5%) followed by loamy sand (20.9%), sandy clay (16.3%) and silt loam (2.3%). On the other hand, the average concentrations of each metallic trace elements were 0.12 pg/g for Cd; 36.6 lag/g for Cr; 9.51 pg/g for Cu; 11.6 ~tg/g for N: 41.5 ~tg/g for Zn and 29.3/ag/g for Pb. Based on the results, it was found out that coarse sediments showed lower levels of metallic trace elements and higher levels in fine sediments. In addition, enrichment factor was calculated to assess the pollution status of the study area. Based on the calculation, the enrichment of metallic trace elements ranked in the following order: Pb 〉 Cd 〉 Zn 〉 Cu 〉 Ni 〉 Cr. The significant enrichment of Pb and moderate enrichment of Cd and Zn indicated that there are anthropogenic inputs while the rest of the metals can be considered from natural sources although there are effects of anthropogenic inputs in some sampling location.
文摘Peatlands represent one of the most important economic resources and abandoned peatlands after mining can be considered as ecological resources by re-vegetation restoration or management. However, some environmental problems like particles from peatlands and their effects in the water system have to be characterized. Since centuries, artificial drainage has been a current practice for the mining of peatlands. Mainly mined for horticultural purpose, New Brunswick's peatlands--predominantly located in the eastern of the province--cover about 140,000 ha. At the downstream end of the drainage system, the water from peatlands flow into sedimentation basins. Drainage waters are often laden with solid particles. Once they have flowed through the ponds to allow sediment settling, the water is released into the water system. This paper describes the spatio-temporal evolution of suspended solids from 12 New Brunswick drained peatlands. The studied sites were characterized by some heterogeneity in the concentration of suspended solids. This study also provides knowledge on the suspended solids amount that can be released by drained peatlands, and it proposes a function to estimate the concentration of suspended solids by using climate variables; and identifies some potential ecological risks.
文摘Nha Trang Bay is famous not only because of its beauty, but also of the biodiversity values, especially coral reefs. Thus, the sea water quality monitoring systems are necessary for effective and available managements to protect the ecosystems and for sustainable development. There have been several monitoring systems here but they have been done separately and unconnectedly. This research was done to take an overview and access the status and changes of water quality from 2007-2014. The data obtained rainy seasons over the years showed a quite good environment here. The environment changes were also monitored and there were some changes between seasons and over years, decreasing, increasing, or unobvious trends. However, the difference was not so much; and there was not the sign of environmental degradation in the bay from 2007 to 2014. Besides, the stoichiometric nutrients limitations were initially assessed. Since Si ratios here were always higher compared to N and P, there was not increased potential for non-diatom algal blooms. Together with the recorded nutrients concentration data, it can be said that there was no evidence of eutrophication in the bay. Although there was partial contamination of some parameters at few moments, the sea water quality of Nha Trang bay was still in a good condition (according to Vietnamese and ASEAN criteria).
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05130703)Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-YW-224)2020-Planning Project of Yantai Institute of Coastal Zone Research of Chinese Academy of Sciences(No.Y254021031-6)
文摘Based on remote sensing and GIS techniques, land use maps in 2000, 2005 and 2010 in China′s coastal zone were produced, and structural raster data of land use were further generated to calculate land use intensity comprehensive index(LUICI) for analyzing land use spatial-temporal characteristics at 1 km scale. Results show that: 1) from the perspective of spatial patterns of landforms at a macro scale, there is a significant difference in land use intensity between the north and the south of China′s coastal zone. Hotspots of changes mainly concentrated in metropolitan areas, estuaries and coastal wetlands; 2) elevation is an important factor that controlling land use spatial patterns at local scale. Land use intensity is much higher within areas below the elevation of 400 m and it decreased significantly as the elevation increasing; 3) there is a significant land-ocean gradient for land use intensity, which is low in island and near-shore areas, but high in the regions that 4–30 km far away the coastline because of much intensive human activities; however, in recent decades land use intensity had been promoted significantly in low near-shore area due to extensive sea reclamations; 4) significant differences of land use intensity were also found among provincial administrative units. A rising trend of land use intensity was found in provincial-level administrative units from 2000 to 2010. To sum up, elevation, land-ocean gradient, socio-economic status and policy are all influencing factors to the spatial patterns and temporal variations of land use intensity in China′s coastal zone.
文摘In early winter it is usual, in cold regions, that ice features approach offshore structures, like offshore platforms, impacting them, in a slow process of constant deformation build up. Interaction follows, in many cases, up to the point where ice-failure caused by bending fracture takes place. This supposes very large contact forces that the structure has to resist. Therefore, quantification of these efforts is of vital importance to the structural design of platforms. In several designs, these platforms are constructed with inclined walls so as to cause ice to fail in a flex-compression mode. In such a case the ice feature is analyzed as a beam constituted of a linear elastic material in brittle state with constant ice thickness. The simplification renders the problem solvable in a close form. However, this hypothesis goes against field observations. Marine currents action, wind and the sequence of contacts among features lead to thickness variations. Here this factor is addressed in the construction of a model, for harmonic forms of variation of thickness profile, and the accompanying curvature variations, whose solution determines field variables used to address the failure question. Due to the deformation dependency of the loading, a numerical scheme for the two-point boundary value problem in the semi-infinite space is developed. Failure pressures are computed based on a Rankine locus of failure. Variations of the order of 20% in the failure loads, as compared to the uniform beam model, are observed.
文摘The aim of the study is to monitor and assess landslide hazards by remote sensing data processing and GIS (Geographic Information Service) spatial analysis. Idukki district, the western Ghats of India was chosen as test area, because of frequent destructive mass wasting processes. Western Ghats is a prominent orographic feature that runs parallel to the south west coast of India. Predicting landslide hazard on a regional scale, namely the assessment of actual and potential mass movement over large area is carried out using Remote Sensing and GIS. A numerical weightage to the causative factors of slope instability such as slope, relative relief, aspect, curvature, drainage density, drainage frequency, land use, road buffer and drainage buffer are assigned as per earlier workers for the purpose of landslide susceptibility zonation. A high degree of match is found between observed and predicted landslide hazard by the procedure employed in the study.
文摘The proliferation of urban development with concentration in population and human-environment interaction has intensified around urban environments. This has resulted in the degradation of urban environments, overuse of natural resources and widespread pollution of ecosystems, The patterns of design initiatives continue to follow unsustainable path with impacts on stream ecosystems. Accordingly, the paper adopts geospatial information systems and sustainability principles for the identification and sequential mapping of stressors impeding natural systems in Southern Mississippi. The results not only reveal that the study area experienced some significant changes in its watershed environments, but the stream habitat ecosystem remains under stress. The recommendations for mitigating the problems range from policy considerations to the adoption of ecosystem approach.
基金supported by the National Key Research Programs (Grant Nos. 2013CB955700 & 2016YFA0601400)the National Natural Science Foundation of China (Grant Nos. 41422603, 41676125 and 91428308)the National Programme on Global Change and Air-Sea Interaction (Grant No. GASI-0301-02-03)
文摘The oceans are the largest carbon pools on Earth, and play the role of a "buffer" in climate change. Blue carbon, the carbon(mainly organic carbon) captured by marine ecosystems, is one of the important mechanisms of marine carbon storage.Blue carbon was initially recognized only in the form of visible coastal plant carbon sequestration. In fact, microorganisms(phytoplankton, bacteria, archaea, viruses, and protozoa), which did not receive much attention in the past, account for more than 90% of the total marine biomass and are the main contributors to blue carbon. Chinese coastal seas, equivalent to 1/3 of China's total land area, have a huge carbon sink potential needing urgently research and development. In this paper, we focus on the processes and mechanisms of coastal ocean's carbon sequestration and the approaches for increasing that sequestration. We discuss the structures of coastal ecosystems, the processes of carbon cycle, and the mechanisms of carbon sequestration. Using the evolution of coastal ocean's carbon sinks in sedimentary records over geologic times, we also discuss the possible effects of natural processes and anthropogenic activities on marine carbon sinks. Finally, we discuss the prospect of using carbon sequestration engineering for increasing coastal ocean's carbon storage capacity.
基金Supported by the National Key Technologies Research and Development Program of China during the 11th Five-Year Plan Period (No. 2006BAC01A14)the Key Project of the Science and Technology Commission of ShanghaiMunicipality,China (Nos. 10dz1200602 and 10dz1200902)
文摘Coastal erosion is currently a major problem along the southern coast of Chongming Island, Shanghai. To enhance the erosion protection ability of coastal shelterbelts, two woody tree species, Taxodium ascendens and Salix babylonica, were planted separately into Phragmites australis + Scirpus mariqueter communities in 2006. Two years later, we investigated whether either of these experiments reduced erosion and increased stability in the native herbaceous plant community. We also examined soil stability and root length density under T. aseendens added, S. babylonica added and native herbaceous vegetation conditions along an intertidal gradient from the soil surface to a depth of 40 cm in each experiment, thus to determine the capacity of T. ascendens and S. babylonica to contribute to shoreline stabilization. Topsoil under the native vegetation had greater stability at the middle and higher intertidal zones because its soil stability index and root length density were significantly higher than in the T. ascendens or S. babylonica planted communities. The effect of T. ascendens on soil stability was not generally better than that of the native vegetation. Only at the 20-30 cm soil depth of the middle intertidal zone and in the 10-20 cm layer of the higher intertidal zone the soil stability index and root length densities under the T. ascendens added condition were significantly higher (P 〈 0.05) than those of the native vegetation. The S. babylonica planted soil had greater stability in the deeper soil layer than the soil under either the native vegetation or the T. ascendens added condition, and its soil stability index and root length density were significant higher (P 〈 0.05) than those of other vegetation conditions at the 30 40 cm soil depth for the lower intertidal zone and at the 20-40 cm layer for middle and higher intertidal zones.
基金Supported by the Natural Resources Data Management System,Department of Science and Technology,Government of India Under Project Scheme (No.ES/11/546/2000,No.ES/11/936(5)/05)
文摘The shoreline is one of the rapidly changing landforms in coastal areas. They are the key element in coastal GIS and provide the most information on coastal land form dynamics. Therefore, accurate detection and frequent monitoring of shorelines is very essential to understand the coastal processes and dynamics of various coastal features. The present study is to investigate the shoreline changes along the coast between Kanyakumari and Tuticorin of south India (where hydrodynamic and morphologic changes occur continuously after the December 2004 tsunami) by using Digital Shoreline Analysis System (DSAS), an extension of ArcGIS. Multidate 1RS and Landsat Satellite data (1999, 2001, 2003, 2005, 2007, and 2009) are used to extract the shorelines. The data is processed by using the ERDAS IMAGINE 9.1 software and analyzed by ArcGIS 9.2 workstation. The rates of shoreline changes are estimated by three statistical methods, namely, End Point Rate (EPR), Linear Regression Rate (LRR), and Least Median of Squares (LMS) by using DSAS. The study reveals that most of the study area has undergoing erosion. Both natural and anthropogenic processes along the coast modify the shoreline configuration and control the erosion and accretion of the coastal zones. The coastal zones along the estuary have experienced accretion due to the littoral processes. The zones with headlands have more eroded than other zones along the study area. The study also shows that the coastal zones where sand is mined have relatively more rate of erosion than that of the other zones. Improper and unsustainable sand mining may also lead to severe erosion problem along this area. The shoreline change rates are altered by various geological processes along the coast. Thus, the present study implies that proper beach filling and nourishment projects should be made in the study area to save from hazards. It also indicates the advantage and suitability of DSAS to assess the shoreline changes compared with the traditional manual shoreline change analysis and promising its applications for coastal zone management in other regions.