海平面上升对珠江口水位影响的分析

珠江三角洲水位变化存在着大量不确定性、不精确性,这些特性既具有模糊特征,也具有灰色特征。在分析珠江三角洲灯笼山站年平均水位的变化特征和闸坡站海平面变化趋势的基础上,利用灰关联法分析代表站灯笼山站年平均水位与流量、海平面、潮差等8个因素的关系,年平均水位与影响因素之间的灰关联度均大于0.7,说明各因子对年平均水位均产生显著影响,其中海平面变化与年平均水位的灰关联度为0.736,说明海平面变化是年平均水位的重要影响因素。选取灰关联度较大的（马＋三）流量、闸坡站海平面、灯笼山站的年最高水位、年最低水位、年平均低潮、年平均潮差这6个指标进行主成分分析。结果表明：第一主成分为径流潮汐作用,第二主成分的代表因素为海平面上升,第三主成分的代表因素为年最高水位;其中海平面上升为代表的第二主成分对年平均水位的贡献率为20.1%。因此,海平面上升对灯笼山站年平均水位的影响虽然弱于径流潮汐作用,但其影响也是显著的。     

珠江三角洲水位演变分析

全球气候变暖导致的海平面加速上升已是不争的事实,其长期累积的结果将给沿海地区造成巨大威胁。利用层次聚类分析法、灰关联法、相关分析法等重点分析了海平面上升对珠江三角洲水位的影响。结果显示：海平面上升对珠江三角洲代表站的年平均水位和年最低水位的影响大于对年最高水位的影响;海平面上升对马口站和三水站水位的影响小于河床下切和径流的影响;海平面上升对珠江河口区水位的影响由三角洲深处向口门区有增强趋势。掌握海平面上升对水位的影响规律,对于河口地区的防灾减灾和水资源的合理开发利用具有重要的指导意义。     

Implications of sea level rise for coastal dune habitat conservation in Wales,UK

The potential impact of future sea level rise and climate change on 15 Welsh coastal dune systems has been investigated. Historical Trend Analysis was undertaken using Ordnance Survey maps to quantify past shoreline change and to permit extrapolation of past trends to predict possible future shoreline positions by 2080–2100. Predictions were also made using the Bruun Rule relationship between sea level rise and shoreline response and an integrated method of assessment, Expert Geomorphological Assessment (EGA), which provides a ‘best estimate’ of future coastline change, taking into account such factors as geological constraints, the nature of past, present and future environmental forcing factors, and known coastal process–response relationships. The majority of the 15 systems investigated experienced a net increase in dune area over the last 100–120 years. Only one (Whiteford Burrows) experienced significant net area loss (>5 ha). EGA predictions suggest that several systems are likely to experience significant net loss of dune habitat over the next century, whilst continued net gain is likely to occur for systems where sediment supply rates remain high. Little net change is predicted in some systems. Considering the 15 dune systems together, it is considered unlikely that net dune habitat loss will exceed net gain over the next 100 years provided that there are no major disruptions to sediment supply and natural coastal processes.     

Sea level rise and eelgrass (Zostera marina) production: A spatially explicit relative elevation model for Padilla Bay, WA

The dynamics that govern the elevation of a coastal wetland relative to sea level are complex, involving non-linear feedbacks among opposing processes. Changes in the balance between these processes can result in significant alterations to vegetation communities that are adapted to a specific range of water levels. Given that current sedimentation rates in Padilla Bay, Washington are likely less than historical levels and that eustatic sea level rise is accelerating, the extensive Zostera marina (eelgrass) meadows in the bay may be at risk of eventual submergence. We developed a spatially explicit relative elevation model and used it to project changes in the productivity and distribution of eelgrass in Padilla Bay over the next century. The model is mechanistic and incorporates many of the processes and feedbacks that govern coastal wetland elevation change. Accretion estimates made using ²¹⁰Pb dating of sediment cores, sediment characteristics measured within cores, and eelgrass productivity and decomposition data were used to initialize and calibrate the model. Validation was performed using an elevation change rate measured with a network of surface elevation tables. Both the field data and model simulations revealed a net accretion deficit for the bay. Simulations using current rates of sea level rise indicated an overall expansion of eelgrass within Padilla Bay over the next century as it migrates from the center of the bay shoreward.     

Trace metals in fish,sediment and water from the south west coast of the Arabian sea,Pakistan

Concentrations of ten metals (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Hg) in the edible muscle of Arius maculatus captured from eight different near‐shore and off‐shore sites off the south west coast of the Arabian Sea, Pakistan, were determined by atomic absorption spectrophotometry. Relevant water and sediment samples from the sites were also analysed for the metals. Zinc showed the highest metal concentration (6.763 μg/g, wet weight) in the muscle of the fish, while Mn and Hg showed lowest level (0.019 μg/g, wet weight). Of all the metals investigated, largest scatter (measured as σ) was observed for Zn (σ = 2.058 /μg/g) in fish muscle, for Fe and Mn in sediment (σ = 27481 and 44.50 μg/g) and for As in water (σ = 0.270 μg/L). The metal distribution data pertaining to water, fish and sediment were examined on the basis of simple metal correlations. The statistical study revealed that Ni, Cr, Pb and Cu had significant positive correlations (r > 0.830 at ρ = 0.01). The finding substantiated a trace metal concentration gradient in the area, thereby indicating that the local marine environment is contaminated by anthropogenic sources.     

Engineering-geological hazards and management in the Mountain Crimea coastal zone

The main engineering-geological hazards and their factors of the Mountain Crimea coastal region are considered. A characteristic shore line site of Cape Kikineiz and its neighboring coastal area near the Katsiveli settlement has been studied in more detail. The important characteristic of the site is a high diversity of geological conditions with numerous manifestations of dangerous engineering-geological processes: shore and hydrological network abrasion, loss of slopes and rocks stability, etc. These processes have intensified during the last decades under the influence of natural and man-induced factors. The results of preliminary study of geo-environmental situation of the area are presented. The program for further research and possible recommendations for rational coastal hazard management and area ecological state improvement are outlined.     

Predicting the spatial distribution of mangroves in a South African estuary in response to sea level rise,substrate elevation change and a sea storm event

The spatial distribution of mangroves in the Mngazana Estuary under sea level rise induced by climate change, together with different substrate elevation change scenarios was predicted for 2020, 2050 and 2100. The present inundation frequency tolerance range was from 0.8 to 31.2 %, equivalent to substrate elevation thresholds of 1.1 and 1.7 m amsl. These thresholds were measured by field surveys and analysis of a gauge station situated near the mouth of the estuary. The predictions were based on the assumption that the inundation frequency tolerance range of mangrove stands remains constant in the future. Through the use of a digital elevation model an initial increase of 2.10 ha year^?1 was found in mangrove area between present and 2020 (from 122.6 to 143.6 ha). This was due to habitat becoming available that is currently too compacted for seedling establishment to occur. This compaction resulted from human and cattle traffic for grazing. Thereafter there would be a mean loss of 0.66 ha year^?1 from 2020 through 2100. Landward migration of mangroves would not take place due to the elevation limit of adjacent non-mangrove areas. In addition, the loss rate would increase to 1.01 ha year^?1 under insufficient sediment accretion, but would decrease to 0.18 ha year^?1 under thriving mangroves condition. The analysis of sea storm event in September 2008 showed that local water level increased by 28 cm and maximum affected area was 87.0 ha (about 71 % of mangrove stands). The inundation continued over 5 days. The results indicated that the combination impact of sea level rise, substrate elevation change and sea storm would possibly be a threat to tropical African estuaries with large flat intertidal areas and mangroves.     

The effects of groundwater table and flood irrigation strategies on soil water and salt dynamics and reed water use in the Yellow River Delta, China

Vegetation management in shallow groundwater table environments requires an understanding of the interactions between the physical and biological factors that determine root-zone soil salinization and moisture. In this study, the effects of groundwater depth and flood irrigation strategies on water and salt dynamics and reed water use were analyzed in the shallow groundwater region of the Yellow River Delta in China using the HYDRUS-1D model. The results indicated that there is a conflict between water, salt stress, and reed water use with variations in groundwater depth. A water table depth of 3.5 m is the minimum limit to maintain a safe level of soil salinity, but at this depth, the environmental stress on reeds is worsened by the decrease in soil water storage. Maintaining the flood pulses on the wetland, especially during May, may be critical for restoring the reed wetland in the Yellow River Delta.     

Agent based simulation of a small catchment water management in northern Thailand: Description of the CATCHSCAPE model

Due to mounting human pressure, stakeholders in northern Thailand are facing crucial natural resources management (NRM) issues. Among others, the impact of upstream irrigation management on downstream agricultural viability is a growing source of conflict, which often has both biophysical and social origins. As multiple rural stakeholders are involved, appropriate solutions should only emerge from negotiation. CATCHSCAPE is a Multi-Agent System (MAS) that enables us to simulate the whole catchment features as well as farmer’s individual decisions. The biophysical modules simulate the hydrological system with its distributed water balance, irrigation scheme management and crop and vegetation dynamics. The social dynamics are described as a set of resource management processes (water, land, cash, labour force). Water management is described according to the actual different levels of control (individual, scheme and catchment). Moreover, the model’s architecture is presented in a way that emphasises the transparency of the rules and methods implemented. Finally, one simulated scenario is described along with its main results, according to different viewpoints (economy, landscape, water management).     

Seasonal variation of the concentrations of 137Cs in sediment,sea water,and some organisms collected from Izmir Bay and Didim

¹³⁷Cs in the marine environment mainly originates from fallout of atmospheric nuclear weapon tests, accidental releases from nuclear facilities, and from the Chernobyl accident. After the latter accident, many studies have been carried out in Turkey. The objective of this study is to assess the spatial distribution of ¹³⁷Cs in the coastal marine environment of the Aegean Sea.

The concentrations of ¹³⁷Cs in sediment, sea water, mussel (Mytilus galloprovincialis), and fish samples collected from the coast of the Aegean Sea at Izmir Bay and near Didim (Akbük) have been monitored for seasonal variability by the means of gamma spectroscopy: they vary between 0.10 ± 0.01 and 1.5 ± 0.3 Bq kg^?1, 1.3 ± 0.1 and 4.3 ± 0.4 Bq m^?3, <0.2 and 1.3 ± 0.3 Bq kg^?1, and 0.20 ± 0.03 and 1.8 ± 0.3 Bq kg^?1, respectively.     

Vertical and spatial distribution of biogenic silica in the sediment of the gulf of Riga,Baltic Sea

The vertical and spatial concentration trends of biogenic silica (BSi) were investigated in a variety of sediment types from the Gulf of Riga. These trends were compared with the concentration of organic carbon to examine how variations in the mass sedimentation and the dissolution rate of BSi versus bacterially mediated oxidation of organic matter affect the distribution of BSi in different environments. The effects of important physical and biogeochemical factors on the distribution of BSi have also been examined.

The concentration of BSi in the surface sediment at accumulation bottoms ranges between 0.8–1.5 mmol/g with an average concentration of 1.1 mmol/g. This is about two times the concentration that has been reported in similar sediments in the open Baltic proper. Much lower concentrations were measured in erosion and transitional areas; on average around 0.2 and 0.6 mmol/g, respectively.

A comparison between recent sedimentation rate measurements (²¹⁰Pb) and concentrations of BSi within different accumulation bottoms suggests an approximate inverse relationship with each other. The importance of variation in the sedimentation rate on the surface BSi concentration is supported by the fact that higher C_org/BSi ratios are found in periphery accumulation zones close to transition areas (larger supply of carbon rich allochthonous material that dilutes settled amounts of BSi) than at accumulation bottoms in the central part of the Gulf. The C_org/BSi ratio in the sediment is always lower than in living siliceous algae which shows that the microbial degradation of organic carbon is always greater than the inorganic dissolution of BSi, irrespective of the assemblage of silica and non‐silica species.

The general vertical concentration pattern at accumulation sites showed a decreased concentration with increased depth down to 2–6 cm below seafloor where the concentration gradually equalizes. The concentration in the equalizing zone is on average about 20% lower than in the uppermost centimeter. This implies that the main part of the BSi entering the accumulation bottoms is permanently buried and that a great amount of silica already has been released during halmyrolysis. The spatial and vertical BSi trends at sites in transitional and erosional areas reflects prevailing sedimentation conditions with a low concentration in sections with a dominance of sand and gravel (no deposition of fine material) and a higher concentration in the sections containing stiff glacial clay (former accumulation area).

The average annual burial amount of BSi in the Gulf has been estimated to be around 50 000 tons of which most is buried in accumulation bottoms outside the central muddy part of the Gulf. The buried amount is about 60% of the annual river load of silica.     

A critical review of the emerging research on the detection and assessment of microplastics pollution in the coastal,marine, and urban Bangladesh

● Coastal and marine regions are the most studied for microplastic pollution. ● Tourism is a major cause of microplastic pollution in coastal regions. ● Sediments contain larger microplastics while fish ingest smaller microplastics. ● Inland lakes, rivers, and freshwater fish are impacted by microplastic pollution. ● Microplastics are found in edible salts, however, presence is less in refined salt. The research on the extent and effects of microplastics pollution in the Global South is only getting started. Bangladesh is a South Asian country with one of the fastest growing economies in the world, however, such exponential economic growth has also increased the pollution threats to its natural and urban environment. In this paper, we reviewed the recent primary research on the assessment of the extent of microplastics pollution in Bangladesh. From the online databases, we developed a compilation of emerging research articles that detected and quantified microplastics in different coastal, marine, and urban environments in Bangladesh. Most of the studies focused on the coastal environment (e.g., beach sediment) and marine fish, while limited data were available for the urban environment. We also discussed the relationship of the type of anthropogenic activities with the observed microplastic pollution. The Cox’s Bazar sea beach in south-east Bangladesh experienced microplastics pollution due to tourism activities, while fishing and other anthropogenic activities led to microplastics pollution in the Bay of Bengal. While microplastics larger than 1 mm were prevalent in the beach sediments, smaller microplastics with size below 0.5 mm were prevalent in marine fish samples. Moreover, the differences in microplastic abundance, size, shape, color, and polymer type found were depended on the sampling sites and relevant anthropogenic activities. It is imperative to identify major sources of microplastics pollution in both natural and urban environment, determine potential environmental and human health effects, and develop mitigating and prevention strategies for reducing microplastics pollution.     

水体、土壤和沉积物中铊的化学形态研究进展

铊(TI)是一个典型性的毒害重金属元素,在环境中的迁移转化行为、富集机制、毒性和生物效应与其赋存化学形态密切相关.本文对水体、土壤和沉积物中Tl化学形态分布、演化特征和化学形态分析方法作了系统总结和评述,并对Tl化学形态分析存在问题及未来发展趋势进行了展望.     

Methodological integration for sustainable natural resource management beyond field/farm level: lessons from the ecoregional initiative for the humid and sub-humid tropics of Asia

SUMMARY

Integrated natural resources management (INRM) has to address both the livelihood goals of farmers and the ecological sustainability of agroecosystems and natural resources. Under the Ecoregional Initiative for the Humid and Sub-Humid Tropics of Asia — Ecor(1)Asia — one major set of activities has been the development of approaches, methodologies, and tools to meet the challenges of INRM research for sustainable agricultural development. Examples provided illustrate the role of these methodologies in the three main phases of knowledge development for improving INRM impact: knowledge generation, knowledge capitalization, and knowledge mobilization. The methodologies are designed for better integration across disciplines, spatial scales, and hierarchical levels of social organization. Attempts are made to quantify trade-offs between biophysical sustainability and socio-economic considerations. The case is made for using these methodologies in a more complementary manner to help bridge the topdown and bottom-up approaches in INRM. Inherent in the developing and implementing of these methodologies is the forging of partnerships and fostering linkages with multiple stakeholders, as well as using the knowledge base and integrative tools as communication platforms.     

Sustainable development and tourism destination management: A case study of the Lillehammer region,Norway

This paper reviews some of the literature and guidance provided for businesses considering responses to the environmental aspects and impacts of their tourist activities. It concentrates on the role of destinations and stakeholders within the destination cooperating and networking to improve environmental performance and on generating a ‘green’ image. In order to move towards a type of tourism consistent with sustainable development (sustainable tourism), it is argued that we need to see enhanced management of a destination, creating opportunities for networking and cooperation between, in particular, service providers. In a case study of Lillehammer, Norway, three projects negotiated, developed and delivered by service providers in the area are examined. These projects looked at hotel management, transport and aesthetics. Success factors are identified, including the involvement of stakeholders, the development of locally orientated codes of conduct, the role and participation of local authorities and the importance of leadership. Findings add to the body of practical help in moving destinations towards sustainable tourism.     

Integrating local knowledge with science and technology in management of soil,water and nutrients: implications for management of natural capital for sustainable rural livelihoods

Harnessing local knowledge and practices for sustainable management of soil, water and nutrients is important for sustainable development. This work aims to understand soil productivity in traditional open-ridging practices and integrate scientific ideas and technologies into traditional practices for enhancing management of soil productivity. Participatory assessments, household surveys, field experiments, observations and analyses of outcomes were used. Participatory assessments revealed declining natural soil fertility and maize productivity over time, a concern reiterated by 82.5% of respondents. Evaluation of ridge tillage practices showed that bean yields were significantly (p?<?0.05) higher by 19–35% in traditional open ridges and increased by 23–38% when ties were integrated. Integration of fertilizers resulted in significantly (p?<?0.05) higher subsequent maize yields in tied ridges than in traditional open ridge and flat cultivation practices. Improved integrated tillage practices resulted in increased soil and water conservation, soil fertility and crop tolerance to prolonged no-rainfall spells. National development policies should create enabling environments for smallholder farmers to integrate modern knowledge and technologies with their traditional knowledge and practices in land management for high and sustained quality of natural capital for secure and sustainable livelihoods.     

Correlations between forest fires in British Columbia, Canada, and sea surface temperature of the Pacific Ocean

Correlations and cross-correlations between forest fires in the province of British Columbia, Canada, and sea surface temperatures in the Pacific Ocean were evaluated. British Columbia has a long Pacific Ocean coastline; given that there may be teleconnections between the province's forest fires and climate variability over the ocean, significant correlations may exist between forest fires and the sea surface temperature of the Pacific Ocean. Fire occurrences and areas burned through lightning-caused and human-caused fires were analyzed against individual 1° × 1° grid cells of anomalies in the sea surface temperature to determine correlations for the period 1950-2006. Significant correlations (p < 0.05) for vast areas of the ocean were found between occurrences of lightning-caused fires and sea surface temperature anomalies for time lags of 1 and 2 years, whereas significant correlations between occurrences of human-caused fires and sea surface temperature anomalies occurred extensively for many time lags. To support the results of this approach, correlations between fire data and the Niño 3.4, Pacific Decadal Oscillation, and Arctic Oscillation indices were tested for the same period. Significant correlations were found between fire occurrences and these indices at certain time lags. Overall, fire occurrence appeared to be more extensively correlated with sea surface temperature anomalies than was area burned. These results support the hypothesis that teleconnections exist between fire activity in British Columbia and sea surface temperatures in the Pacific Ocean, and the correlations suggest that linear regression models or other regression techniques may be appropriate for predicting fire severity from the sea surface temperatures of one or more previous years.     

Water shortages and countermeasures for sustainable utilisation in the context of climate change in the Yellow River Delta region,China

With an increasing population and rapid development of the economy and society of the Yellow River Basin region, the Yellow River is at crisis point. The discrepancy between supply and demand of water resources is a key issue. In 2000–2006, the mean annual discharge of the Yellow River entering the delta was 13.2 billion m³, a reduction of 18.6 billion m³ compared with the 1980s, and 9 billion m³ less than in the 1990s. The water requirements of various sectors are increasing. Large amounts of water essential to maintain the health of the delta ecosystem have been diverted for other users. The lower river channel is shrinking and the threat of flooding is becoming severe. Moreover, water pollution is increasing to a serious level; the river mouth ecosystem is subject to degradation. Due to overall decreased flow into the delta, and almost no flow into the delta for much of the year except in wet periods, biodiversity is threatened and there has been degradation of the ecological environment. In view of the water scarcity and variation in water supply, particularly in the context of climate change, measures need to be taken to realise sustainable water use in the Yellow River Delta region. In view of the lack of a complete index system for sustainable utilisation of regional water resources in China, this paper examines the major countermeasures for sustainable water use in the region. A rational adjustment mechanism for water prices is needed. Adjustment of agricultural infrastructure and water saving need to be directed by water prices, and thus the reasonable exploitation of groundwater must also be directed by water prices. Participation of the public is to be encouraged, with the development of a water user association that will become involved in formulating water rights, water allocation and water prices. Decision-making, management and supervision of this association will be done in a democratic way to promote the social management of water saving.     

Evaluating the effects of future climate change and elevated CO2 on the water use efficiency in terrestrial ecosystems of China

Water use efficiency (WUE) is an important variable used in climate change and hydrological studies in relation to how it links ecosystem carbon cycles and hydrological cycles together. However, obtaining reliable WUE results based on site-level flux data remains a great challenge when scaling up to larger regional zones. Biophysical, process-based ecosystem models are powerful tools to study WUE at large spatial and temporal scales. The Integrated BIosphere Simulator (IBIS) was used to evaluate the effects of climate change and elevated CO₂ concentrations on ecosystem-level WUE (defined as the ratio of gross primary production (GPP) to evapotranspiration (ET)) in relation to terrestrial ecosystems in China for 2009-2099. Climate scenario data (IPCC SRES A2 and SRES B1) generated from the Third Generation Coupled Global Climate Model (CGCM3) was used in the simulations. Seven simulations were implemented according to the assemblage of different elevated CO₂ concentrations scenarios and different climate change scenarios. Analysis suggests that (1) further elevated CO₂ concentrations will significantly enhance the WUE over China by the end of the twenty-first century, especially in forest areas; (2) effects of climate change on WUE will vary for different geographical regions in China with negative effects occurring primarily in southern regions and positive effects occurring primarily in high latitude and altitude regions (Tibetan Plateau); (3) WUE will maintain the current levels for 2009-2099 under the constant climate scenario (i.e. using mean climate condition of 1951-2006 and CO₂ concentrations of the 2008 level); and (4) WUE will decrease with the increase of water resource restriction (expressed as evaporation ratio) among different ecosystems.     

Perfluorinated compounds in water and sediment from coastal regions of the northern Bohai Sea,China

Concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and other perfluorinated compounds (PFCs) were measured in water and sediment from coastal Bohai Bay and surrounding rivers flowing into the bay. Of the 15 PFCs measured, PFOS and PFOA were detected with the greatest frequency. Concentrations in water ranged from<0.2 to 31 ng·L^?1 and<1.0 to 82 ng·L^?1 for PFOS and PFOA, respectively. Concentrations of PFOS and PFOA in sediments ranged from<0.1 to 2.0 ng·g^?1 dw and<0.1 to 0.5 ng·g^?1 dw, respectively. Concentrations of PFCs in Bohai Bay were less than those observed in other areas in Asia, but greater concentrations of ∑PFCs were observed in the Dalin River with concentrations increasing from upstream to downstream, and the greatest concentrations in sediment were observed in tidal flats. The ratio of ∑PFCs in sediment and water indicated that sediment could serve as a significant sink for PFUnA.