Critical coastal issues of Sagar Island, east coast of India

Sagar Island, situated in the east coast of India and one of the biggest deltas in Sundarban group, faces coastal erosion and degradation of coastal vegetation and various natural hazards. Erosion is mainly due to clay mining, wave activities, and the impact of river and tidal currents of Muri Ganga and Hugly Rivers. Further, the coastal zone of Sagar Island faces increasingly severe problems of rapidly growing human population, deteriorating environmental quality, and loss of critical habitats. Sagar Island has been victimized several times by tropical cyclones and influenced daily by tidal fluctuations. The island needs immediate attention on the coastal zone in order to protect the shoreline and ecosystem. The capability of satellite remote sensing to provide synoptic, repetitive, and multispectral data has proved to be very useful in the inventory and monitoring of critical coastal issues. Sagar Island and its environs are subjected to both natural and anthropogenic activities that continuously modify the region.     

Land cover change of watersheds in Southern Guam from 1973 to 2001

Land cover change can be caused by human-induced activities and natural forces. Land cover change in watershed level has been a main concern for a long time in the world since watersheds play an important role in our life and environment. This paper is focused on how to apply Landsat Multi-Spectral Scanner (MSS) satellite image of 1973 and Landsat Thematic Mapper (TM) satellite image of 2001 to determine the land cover changes of coastal watersheds from 1973 to 2001. GIS and remote sensing are integrated to derive land cover information from Landsat satellite images of 1973 and 2001. The land cover classification is based on supervised classification method in remote sensing software ERDAS IMAGINE. Historical GIS data is used to replace the areas covered by clouds or shadows in the image of 1973 to improve classification accuracy. Then, temporal land cover is utilized to determine land cover change of coastal watersheds in southern Guam. The overall classification accuracies for Landsat MSS image of 1973 and Landsat TM image of 2001 are 82.74% and 90.42%, respectively. The overall classification of Landsat MSS image is particularly satisfactory considering its coarse spatial resolution and relatively bad data quality because of lots of clouds and shadows in the image. Watershed land cover change in southern Guam is affected greatly by anthropogenic activities. However, natural forces also affect land cover in space and time. Land cover information and change in watersheds can be applied for watershed management and planning, and environmental modeling and assessment. Based on spatio-temporal land cover information, the interaction behavior between human and environment may be evaluated. The findings in this research will be useful to similar research in other tropical islands.     

Monitoring the drastic growth of ship breaking yards in Sitakunda: a threat to the coastal environment of Bangladesh

The vast coastal and marine resources that occur along the southern edge of Bangladesh make it one of the most productive areas of the world. However, due to growing anthropogenic impacts, this area is under considerable environmental pressure from both physical and chemical stress factors. Ship breaking, or the dismantling and demolition of out-of-service ocean-going vessels, has become increasingly common in many coastal areas. To investigate the extent of ship breaking activities in Bangladesh along the Sitakunda coast, various spatial and non-spatial data were obtained, including remote sensing imagery, statistical records and published reports. Impacts to coastal and marine life were documented. Available data show that ship breaking activities cause significant physical disturbance and release toxic materials into the environment, resulting in adverse effects to numerous marine taxonomic groups such as fish, mammals, birds, reptiles, plants, phytoplankton, zooplankton and benthic invertebrates. Landsat imagery illustrates that the negatively impacted coastal area has grown 308.7 % from 367 ha in 1989 to 1,133 ha in 2010. Physicochemical and biological properties of coastal soil and water indicate substantially elevated pollution that poses a risk of local, regional and even global contamination through sea water and atmospheric transport. While damage to the coastal environment of Bangladesh is a recognized hazard that must be addressed, the economic benefits of ship breaking through job creation and fulfilling the domestic demand for recycled steel must be considered. Rather than an outright ban on beach breaking of ships, the enterprise must be recognized as a true and influential industry that should be held responsible for developing an economically viable and environmentally proactive growth strategy. Evolution of the industry toward a sustainable system can be aided through reasonable and enforceable legislative and judicial action that takes a balanced approach, but does not diminish the value of coastal conservation.     

Sediment fluxes and the littoral drift along northeast Andhra Pradesh Coast, India: estimation by remote sensing

The littoral drift regime along the northeastern coast of India was investigated by analyzing coastal drift indicators and shoreline changes based on multitemporal satellite images. The study of offshore turbidity patterns and quantitative estimation of suspended sediments was undertaken to understand the magnitude and direction of movement of sediment fluxes. The study revealed that: (1) the character of coastal landforms and sedimentation processes indicate that the sediment transport is bidirectional and monsoon dependent; (2) multidate, multitemporal analysis of satellite images helps to show the nature of sediment transport along the coast. The dominant net sediment transport is in a NE direction along the eastern coast of India. Finally, this assessment demonstrates the potential of remote sensing technology in understanding the coastal morphometric changes, long-term sediment transport, shoreline changes, and offshore turbidity distribution pattern and the implications for the transport of sediment-associated pollutants.     

Using Aerial Video to Train the Supervised Classification of Landsat Tm Imagery for Coral Reef Habitats Mapping

Management of coral reef resources is a challenging task, in many cases, because of the scarcity or inexistence of accurate sources of information and maps. Remote sensing is a not intrusive, but powerful tool, which has been successfully used for the assessment and mapping of natural resources in coral reef areas. In this study we utilized GIS to combine Landsat TM imagery, aerial photography, aerial video and a digital bathymetric model, to assess and to map submerged habitats for Alacranes reef, Yucatán, México. Our main goal was testing the potential of aerial video as the source of data to produce training areas for the supervised classification of Landsat TM imagery. Submerged habitats were ecologically characterized by using a hierarchical classification of field data. Habitats were identified on an overlaid image, consisting of the three types of remote sensing products and the bathymetric model. Pixels representing those habitats were selected as training areas by using GIS tools. Training areas were used to classify the Landsat TM bands 1, 2 and 3 and the bathymetric model by using a maximum likelihood algorithm. The resulting thematic map was compared against field data classification to improve habitats definition. Contextual editing and reclassification were used to obtain the final thematic map with an overall accuracy of 77%. Analysis of aerial video by a specialist in coral reef ecology was found to be a suitable source of information to produce training areas for the supervised classification of Landsat TM imagery in coral reefs at a coarse scale.     

Land cover changes on the coastal zone of Candarli Bay, Turkey using remotely sensed data

Land cover of the Earth is changing dramatically because of human activities. Information about changes is useful for management of natural resources. Rapid land cover changes have taken place in many coastal areas of Turkey over the last two decades due to urbanization and land degradation. In this paper, land cover change dynamics were investigated by the combined use of satellite remote sensing and geographical information systems. The main objective of the study was to determine land-cover transition rates among land cover types in coastal areas of Turkey. A time series of Landsat TM and ASTER images were used to gather land cover change data of the coastal line of Candarli Bay, Izmir, Turkey. The images were classified using supervised classification and a post-classification comparison approach was used in change detection. The results show significant increase in urban areas but decrease in semi natural and agricultural areas.     

Ecosystem services in environmental assessment — Help or hindrance?

This paper presents a critical analysis of the potential role of ecosystem services within environmental assessment, including both strategic environmental assessment (SEA) and environmental impact assessment (EIA). It identifies some of the common problems with current environmental assessment practice and then explores whether integrating ecosystem services may be able to help address some of these problems. Case studies are included to illustrate different approaches to using ecosystem services within environmental assessment and to highlight how context (e.g. sector, scale, environmental situation) will influence the most appropriate way of integrating ecosystem services into environmental assessment practice. The analysis also reflects on how ecosystem services' potential role may, or may not, differ from previous integrated approaches to environmental assessment and what lessons can be learnt from their development.Two main approaches are recognised from the literature and the case studies to integrating ecosystem services within environmental assessment: firstly a comprehensive approach, where the assessment framework is entirely guided by ecosystem services; and secondly a philosophical approach that applies more of a light-touch ecosystems-thinking mind-set, helping to frame the assessment methodology rather than fundamentally defining it. Inevitably, there are variations between these two extremes, and benefits and criticisms of both.The authors conclude that ecosystem services provides a potentially valuable framing for environmental assessment, but that it requires a pragmatic, context specific consideration of how ecosystem services can be used to help address some of the common problems with current environmental assessment practice. There is also a need to recognise that at times it may just not be appropriate if it does not provide added value.     

Shoreline change analysis of Vedaranyam coast, Tamil Nadu, India

The coastal zone is one of the nation’s greatest environmental and economic assets. The present research aims at studying the shoreline changes along Vedaranyam coast using conventional and modern techniques including field sampling, remote sensing, and geographical information system (GIS). The study area was divided into three zones. Dynamic Land/Sea polygon analysis was performed to obtain the shore line changes at different time periods between 1930 and 2005. From the multidate shoreline maps, the rate of shoreline change was computed using linear regression rate and end point rate. Further, the shoreline was classified into eroding, accreting, and stable regions through GIS analysis. The eroding, accreting, and stable coastal stretch along Vedaranyam is observed as 18 %, 80.5 %, and 1.5 %, respectively. Net shoreline movement is seaward, i.e., the coast is progressive with an average rate of 5 m/year. A maximum shoreline displacement of 1.3 km towards the sea is observed near Point Calimere. During the Asian Tsunami 2004, the eastern part of the study area showed high erosion. Sediment transport paths derived from the grain size analysis of beach sediments collected during different seasons help to identify the major sediment source and sinks. Point Calimere acts as the major sink for sediments whereas Agastiyampalli and Kodiakkarai are found to be the major sources for the sediment supply along the Vedaranyam coast. Shoreline change study from field and satellite data using GIS analysis confirms that Vedaranyam coast is accreting in nature.     

A combinated approach to investigate the biochemistry and hydrography of a shallow bay in the South Adriatic Sea: the Gulf of Manfredonia (Italy)

The main goal of this study is to understand the hydrological and biochemical set up and processes of a marine coastal area located in the western side of the south Adriatic sea (the gulf of Manfredonia) by the use of both satellite images and in situ investigations A water sampling in the gulf of Manfredonia was performed at 18 fixed stations in June 2003; physico-chemical and biological parameters (temperature, salinity, dissolved oxygen and fluorescence) were measured along the water column and water samples were collected to analyse dissolved nutrients (ammonia, nitrite, nitrate, phosphate and silicate), total nutrients (nitrogen and phosphorus), chlorophyll a and total suspended solids. Surface spatial distributions of field collected data were examined to characterize biochemical and hydrographic conditions of the Gulf of Manfredonia and these results were related with the remote sensing analysis data. Remote sensed data (obtained by Landsat 7 TM and Modis Terra) were processed to obtain maps of chlorophyll a, temperature and optical characteristics of the gulf; these maps were compared to in situ data. From physico-chemical measurements no stratification was observed in the water column except for the south-eastern area. High concentrations of silicate and ammonia were observed in the northern zone of the gulf, while nitrate, phosphate, chlorophyll a and total suspended solids distributions showed higher values in the central coastal zone. These results were confirmed by remote sensing analysis; Modis elaboration showed a distribution with higher concentrations of chlorophyll a near the coast and Landsat images highlighted the extension of the surrounding agricultural areas crossed by the two main rivers which discharge into the gulf. The integration between field data with the remote sensing analysis showed to be a valid support in coastal zone management.     

核电站温排水遥感监测方法研究——以田湾核电站为例

以江苏省连云港田湾核电站为主要研究区，通过热红外遥感技术研究温排水热污染现象，综合应用美国Landsat卫星热红外波段数据及地面气象测站资料，定量反演核电站建成前后附近海域水温分布与变化情况。研究结果表明，遥感技术完全能够满足温排水监测要求，对于完善近岸海域生态环境保护工作具有积极意义。     

滨海湿地环境评价方法研究

为研究我国典型滨海湿地环境评价方法,利用卫星遥感技术,结合地面生态调查,构建了以自然湿地面积比例、人工岸线比例等8项因子共同组成的指标体系,通过层次分析法和专家打分法进行权重赋值后,阐述了数据处理和计算的主要流程,提出了滨海湿地环境指数CWEI的概念和表征意义。应用上述方法对江苏盐城湿地珍禽国家级自然保护区进行了典型示范评价,结果表明该方法能够较好地反映滨海湿地环境状况与变化趋势。     

Barriers to the use of remote sensing in providing environmental information

Remote sensing from aircraft and earth-observing satellites is an essential source of environmental information and, at regional and global scales, remote sensing from satellites is often the only way in which some information can be collected. Naturally there are technical limitations, such as low resolution and the inability of optical sensors to see through clouds that restrict the use of satellite data, but technology is moving rapidly and major advances can be expected during the current decade, especially from radar satellites.The main barriers to the use of environmental information provided by remote sensing are not technological, but include cost and a need for training and transfer of technology, and a requirement for users to depart from traditional methods where new technology offers distinct advantages. Perhaps the most important contributions that users of remote sensing data can make to breaking down the barriers to the use of environmental data is to provide very clear statements of their information requirements so that technology can develop to meet these requirements.     

On applications of remote sensing for environmental monitoring

Modern airborne and satellite remote sensing techniques offer attractive opportunities to coastal monitoring systems. Improvements of the evaluation of larger scales phenomena and processes due to the synopticity of the remote sensing data are of particular interest. However, some uncertainties and limitations about remote sensing must be considered. Microwave, infrared and visible radiation methods and their applications are briefly discussed and some applications are demonstrated. Special attention is paid to the remote sensing of various pollutants in the sea, in particular with respect to oil pollution.Promising developments of the remote sensing methods for coastal monitoring are to be expected from the European remote sensing satellite missions ERS 1 and ERS 2.Combination of these observations with simultaneous in situ measurements from ships (sea truth) appears to be most advantageous for the interpretation of the collected data.     

Environmental Impact Assessment of the Mining and Concentration Activities in the Kola Peninsula, Russia by Multidate Remote Sensing

On the Kola Peninsula, the mining and concentration industry exerts anthropogenic impact on the environment. Tailing dumps cause airborne pollution through dusting, and waterborne pollution due to direct dumping and accidental releases. The objectives were: (1) to analyse multidate satellite imagesfor 1964–1996 to assess the environmental pollution from themining and concentration activity in the Kola in temporal perspective; (2) to evaluate remote sensing methods for integrated environmental impact assessment. The area of mining and industrial sites steadily expands and amounted to 94 km² in 1996. The polluted water surface amounted to at least 150 km² through dumping in 1978 and to 106 km² in1986 due to dusting. Thus, the impact from the mining and concentration activity should be reconsidered as more significant than it was officially anticipated. In the past the main mechanism of pollution wasdirect dumping into the lakes. Currently and in future, airborne pollution after dusting storms will dominate. The effective recultivation of the tailing dumps will be a long-term process. For effective assessment of impacts from the mining and concentration industry, remote sensing methods should be complemented by in-situ measurements, fieldwork, and mathematical modelling.     

Assessment of chlorophyll-a variations in high- and low-flow seasons in Apalachicola Bay by MODIS 250-m remote sensing

Chlorophyll-a (chl-a) is considered as a primary indicator for water quality and foods for oyster growth in Apalachicola estuarine ecosystem. Assessment of chl-a concentration variation in response to river inflow is important for estuarine environmental research and management. In this study, remote sensing analysis has been conducted to evaluate the effects of river inflow on chlorophyll concentrations in Apalachicola Bay of Florida in the northeast Gulf of Mexico. A remote sensing model for chl-a was improved and applied to map spatial distributions of chl-a by using Moderate Resolution Imaging Spectroradiometer (MODIS) 250-m resolution imageries in high-flow and low-flow seasons in 2001 and 2008. Chl-a values approximately ranged from the minimum 6 μg/l to the maximum 29 μg/l in the study period. Maximum chl-a concentration in high-flow season was almost twice above that in low-flow season. The averaged mean and minimum chl-a level in the high-flow season were approximately 42 and 28 % higher than those in low-flow season, respectively. The remote sensing mapping of chl-a was able to show spatial variations of chl-a in the entire bay under different flow conditions, which indicated its advantage over the traditional field data sampling for monitoring water quality over a large area of estuary. The MODIS 250-m remote sensing regression model presented from this study can be used to support monitoring and assessment of the spatial chl-a distribution in the bay for environmental research and management in Apalachicola Bay.     

Regulating human interventions in Colombian coastal areas: Implications for the environmental licensing procedure in middle-income countries

Although anthropogenic impacts could be assessed in any environment, coastal areas pose a particular challenge because of their special nature as the interface between land and sea. Therefore, this study evaluates the environmental regulatory framework for coastal interventions in Colombia, as an archetype of medium income countries (MICs), to derive implications for the environmental licensing procedure (ELP). The methods comprised two simultaneous pathways: a. An inventory of human interventions at the large scale area of the Colombian Caribbean Coast, with an estimation of the overall environmental impact; b. An analysis of the ELP in Colombia during the last 25 years. The study evidences several weaknesses, such as a consistent reduction in the number of works and activities covered in each new legislative. Moreover, the Colombian ELP currently regulates only four of the ten types of interventions with greater effect in its coastal zones. The discussions highlight some policy implications for the ELP in MICs, mainly based on how the impact of a type of intervention can be magnified in proportion to its frequency of occurrence, and the need to articulate instruments of environmental management and territorial planning. At last, the need to evolve the impact assessment of human interventions from environmental factors toward socio-natural processes is evidenced and further addressed, by the introduction of a susceptibility approach inspired on geomorphological processes. Overall, this study highlights important gaps of the Colombian ELP for coastal environments, which entails valuable lessons for MICs.     

分类学多样性指数评价生态环境的研究进展

生物多样性是环境监测环境保护的重要内容之一,在众多的生物多样性指数中,包含分类学信息的指数具有明显的特点和优势。近20年来,在海洋、淡水、陆地等生境中开展了许多分类学多样性指数相关的应用研究。一些分类学多样性指数能够在一定程度上灵敏地反映出环境退化和污染,在环境监测能力和历史资料对比等方面优于传统多样性指数。在使用分类学差异性指数区分人类干扰和自然变化时结论不一,分类学多样性指数的应用受到一些因素的影响,例如生物类群选择、生境、水深、纬度等是产生分歧的因素。扩大研究范围,明确应用范围可有效发挥分类学差异性指数在环境保护和评价中的作用。     

河流物理生境遥感监测研究与应用分析

简述了国内外河流物理生境监测研究进展和应用。从水生态监测体系完整性和物理生境监测手段的优缺点等方面,研究了河流物理生境遥感监测的必要性;结合我国水生态环境管理形势,介绍了河流物理生境遥感监测的应用领域;以辽河干流盘锦段为例,进行了物理生境遥感监测评估的实例分析。     

Remote sensing of aquatic vegetation: theory and applications

Aquatic vegetation is an important component of wetland and coastal ecosystems, playing a key role in the ecological functions of these environments. Surveys of macrophyte communities are commonly hindered by logistic problems, and remote sensing represents a powerful alternative, allowing comprehensive assessment and monitoring. Also, many vegetation characteristics can be estimated from reflectance measurements, such as species composition, vegetation structure, biomass, and plant physiological parameters. However, proper use of these methods requires an understanding of the physical processes behind the interaction between electromagnetic radiation and vegetation, and remote sensing of aquatic plants have some particular difficulties that have to be properly addressed in order to obtain successful results. The present paper reviews the theoretical background and possible applications of remote sensing techniques to the study of aquatic vegetation.     

华北地区滨海湿地生态系统健康评价体系构建研究

以华北地区滨海湿地中的天津宁河七里海湿地为例,以PSR模型作为评价基础框架,运用可持续发展的理论、环境生态学、城市生态学、景观生态学等科学理论,结合社会经济资料收集、地面数据的采集与生态环境现状调查,应用层次分析法(AHP),在咨询专家意见的基础上,利用T L Saaty的标度法,构建了华北地区滨海湿地生态系统健康评价体系。体系由压力子系统、状态子系统、响应子系统构成,共筛选出三大类共计19项综合指标,其中压力指标6项、状态指标9项、响应指标4项。通过实际验证,该评价体系能客观地反映出湿地生态系统健康水平,可为环境管理部门的科学决策以及湿地的可持续发展提供技术支持,可供其他滨海地区湿地评价时参考。