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1.
Coastal reclamation and modifications are extensively carried out in Bahrain, which may physically smother the coastal and subtidal habitats resulting in changes to abundance and distribution of macrobenthic assemblages. A microcosm laboratory experiment using three common macrobenthic invertebrates from a proposed reclaimed coastal area was preformed to examine their responses to mud burial using marine sediment collected from a designated borrow area. Significant difference in numbers of survived organisms between control and experimental treatments with a survival percentage of 41.8% for all of the selected species was observed. The polychaete Perinereis nuntia showed the highest percentage of survival (57.1%) followed by the bivalve Tellinavaltonis (42.3%) and the gastropod Cerithidea cingulata (24.0%). Quantifying species responses to sediment burial resulted from dredging and reclamation will aid in predicting the expected ecological impacts associated with coastal developments and subsequently minimizing these impacts and maintaining a sustainable use of coastal and marine ecosystems in the Arabian Gulf.  相似文献   

2.
Ground deformation of reclaimed land is a key issue for reclamation design, construction and sustainable development in coastal areas as this consolidation process of the underlying compressible marine sediment sequences over very long‐time periods could lead to damage of both ground constructions and underground facilities. In this case study, we have investigated the spatial and temporal characteristics of residual reclamation settlement of Chek Lap Kok Airport, Hong Kong, one of the largest land reclamation projects worldwide. A total of 25 time series ENVISAT ASAR datasets, acquired between December 2003 and October 2008, were used to retrieve settlement rates and deformation history at high resolution and accuracy by means of advanced Synthetic Aperture Radar Interferometry (InSAR). The InSAR‐derived results show a fairly homogenous and stable pattern in the sectors of the airport site corresponding to the two original islands of Chek Lap Kok and Lam Chau. In contrast, a relatively high spatial settlement variability, ranging from moderate (3–7?mm/yr) to strong (>10?mm/yr) settlement rates, was discovered within the majority of the reclaimed portion of the airport. A joint analysis of InSAR observations and geological materials indicates that the variability of the recorded residual settlement was highly correlated with the variations of thickness and pre‐consolidation state of alluvial deposits below the reclamation. A quantitative comparison analysis also has been carried out between time series InSAR observations and theoretical estimates of residual settlement modelled by geotechnical investigations. The results imply that a primary consolidation process in alluvial deposits below the reclamation might be delayed with respect to the predicted results and may still have been occurring in most reclaimed areas during the investigation period (2003–2008); the time to complete it could stretch to decades depending on hydraulic conductivity and natural drainage conditions. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

3.
Eutrophication and associated occurrence of hypoxic condition could cause significant damage to marine ecosystems, resulting in considerable economic losses to fisheries and aquaculture and is a major source of stress that fish often have to contend with in order to survive. This problem is likely to be exacerbated in the coming years, since the wastewater treatment facilities is unlikely to catch up with increasing human activities. Moreover, large-scale reclamation projects in coastal areas have recently been increased, and these activities certainly have adverse impacts on water quality and fisheries resources. Coastal construction has a significant role in the development of hypoxic water by changing the current and mixing pattern of water. Changes in species composition and decreases in species richness and diversity have been well documented in hypoxic systems. Hypoxia could cause endocrine disruption in fish and eliminate populations of sensitive species. Shallow coastal areas are of great importance for the special nursery of fish and shellfish and land reclamation in these areas cause strong damage to fisheries. Although the tolerance of aquatic life to hypoxia is known, there is no information about the mortality of fish caused by hypoxia because fish can swim around it and no modeling study has yet been carried out. Criteria that influence the movement of fish are: amounts of food, water temperature and depth, dissolved oxygen concentration and nature of seabed. However, among these, water temperature and dissolved oxygen are the most crucial parameters that affect survival, movement and growth of fish. In this paper, a model of fish preference and mortality for environmental conditions was developed and applied to the Hakata Bay where hypoxic water occurs every summer. For the purpose of this study, a field survey of fish behavior under hypoxic water was conducted by releasing marbled sale (Pleuronectes yokohamae) in the inner bay. Moreover, a series of preference tests for DO, salinity and temperature in the laboratory were conducted in order to decide preference parameters of fish. Using the results of both field and laboratory studies, a sub-module of fish preference and mortality was coded within an integrated hydrothermal and eutrophication model (CHEM) to predict the behavior and mortality of marbled sale when hypoxia would occur in the bay. The model could reasonably simulate the behavior of the fish under hypoxia. An assessment of the impact of the ongoing land reclamation project of about 401 ha in the Wajiro tidal flat zones at the head of the bay on the fisheries resources was also conducted using the model. The results showed that the artificial land lowered the mortality rate of fish under hypoxic condition in the bay during the summer period.  相似文献   

4.
Guo H  Jiao JJ 《Ground water》2007,45(3):362-367
Land reclamation in coastal areas may have a significant effect on local ground water systems. Steady-state analytic solutions based on Dupuit and Ghyben-Herzberg assumptions are derived to evaluate this effect. Two situations are considered, both with ground water flow resulting from precipitation recharge: the coastal aquifer of an extensive landmass and an island. The results show that after reclamation, the water table rises and the salt water-fresh water interface moves seaward. The degree of these changes depends on the extent of reclamation and the hydraulic conductivity of the fill material. For the island situation, the reclamation displaces the ground water divide and changes the ground water conditions in the entire island. An unintended advantage of the reclamation is an increase of fresh ground water resource because the reclaimed land can be an additional aquifer and rain recharge takes place over a larger area.  相似文献   

5.
Due to increasing development Southeast Asia’s coastlines are undergoing massive changes, but the associated impacts on marine habitats are poorly known. Singapore, a densely populated island city–state, is a quintessential example of coastal modification that has resulted in the (hitherto undocumented) loss of seagrass. We reconstructed the historic extent and diversity of local seagrass meadows through herbarium records and backwards extrapolation from contemporary seagrass locations. We also determined the current status of seagrass meadows using long-term monitoring data and identified the main threats to their presence in Singapore. Results show that, even though ∼45% of seagrass has been lost during the last five decades, species diversity remains stable. The main cause of seagrass loss was, and continues to be, land reclamation. We conclude that strict controls on terrestrial runoff and pollution have made it possible for seagrass to persist adjacent to this highly urbanised city–state.  相似文献   

6.
Land reclamation has become one of the great concerns of many coastal states for its serious environmental and ecological effects. User charge is an effective market-based approach for regulating land reclamation. The user change should be designed to reflect the full effect of converting sea to land to ensure sustainable use of marine resources. In this paper, we present an ecological-economic framework to estimate the user charge that covers both the ecological damages and the rent associated with the reclaimed land. We apply the framework to Xiamen’s West Sea. Results of the case study suggest that the rents of reclaimed land for industrial and commercial uses are 49 yuan/m2 and 1,066–2,704 yuan/m2, respectively. The unit value of ecological damages of land reclamation is 605 yuan/m2. The present user charge is too low to regulate excessive land reclamation. The user charge for land reclamation in the study area should be modified to 653 yuan/m2 for industrial uses and 35–40% of adjacent land prices for commercial uses.  相似文献   

7.
A 182-year long record of trace metal concentrations of aluminum, zinc and lead was reconstructed from a massive Porites coral skeleton from southeastern Hong Kong to evaluate the impacts of anthropogenic activity on the marine environment. Zn/Ca and Pb/Ca ratios fluctuate synchronously from the early 19th century to the present, indicating that the marine environment has been anthropogenically influenced since industrialization. Additionally, land reclamation, mining, and ship building activities are recorded by elevated Al/Ca ratios from 1900 to 1950. The coral record indicates that high levels of Zn, Pb and Al occur coincidentally with local wars, and may have contributed to partial colony mortality. Pb/Ca does not correlate well with hemispheric proxy records after 1950, indicating that coastal corals may be recording local rather than hemispheric contamination. Pb/Ca levels in Hong Kong, Guangdong and Hainan corals imply a continuous supply of Pb-based contamination to southern China not reflected in hemispheric signals.  相似文献   

8.
Kenya     
The Kenya coast is bathed by the northward-flowing warm waters of the East Africa Coastal Current, located between latitudes 1 and 5° S. With a narrow continental shelf, the coastal marine environments are dominated by coral reefs, seagrass beds and mangroves, with large expanses of sandy substrates where river inputs from Kenya's two largest rivers, the Tana and Athi rivers, prevent the growth of coral reefs. The northern part of the coast is seasonally influenced by upwelling waters of the Somali Current, resulting in lower water temperatures for part of the year. The coast is made up of raised Pleistocene reefs on coastal plains and hills of sedimentary origin, which support native habitats dominated by scrub bush and remnant pockets of the forests that used to cover East Africa and the Congo basin. The marine environment is characterized by warm tropical conditions varying at the surface between 25°C and 31°C during the year, stable salinity regimes, and moderately high nutrient levels from terrestrial runoff and groundwater. The semi-diurnal tidal regime varies from 1.5 to 4 m amplitude from neap to spring tides, creating extensive intertidal platform and rocky-shore communities exposed twice-daily during low tides. Fringing reef crests dominate the whole southern coast and parts of the northern coast towards Somalia, forming a natural barrier to the wave energy from the ocean. Coral reefs form the dominant ecosystem along the majority of the Kenya coast, creating habitats for seagrasses and mangroves in the lagoons and creeks protected by the reef crests. Kenya's marine environment faces a number of threats from the growing coastal human population estimated at just under three million in 2000. Extraction of fish and other resources from the narrow continental shelf, coral reef and mangrove ecosystems increases each year with inadequate monitoring and management structures to protect the resource bases. Coastal development in urban and tourist centers proceeds with little regard for environmental and social impacts. With a faltering economy, industrial development in Mombasa proceeds with few checks on pollution and other impacts. In 1998 Kenya's coral reefs suffered 50–80% mortality from the El Niño-related coral bleaching event that affected the entire Indian Ocean. The institutional, human resource and legal infrastructure for managing the coastal environment has in the past been low, however these are rapidly improving with the revitalization of national institutions and the passing in 1999 of an Environment Act. Marine Protected Areas are the key tool currently used in management of marine ecosystems, and focus principally on coral reefs and biodiversity protection. New initiatives are underway to improve application of fisheries regulations, and to use Integrated Coastal Area Management (ICAM) as a framework for protecting marine and coastal environments.  相似文献   

9.
《Marine pollution bulletin》2012,64(5-12):508-515
A 182-year long record of trace metal concentrations of aluminum, zinc and lead was reconstructed from a massive Porites coral skeleton from southeastern Hong Kong to evaluate the impacts of anthropogenic activity on the marine environment. Zn/Ca and Pb/Ca ratios fluctuate synchronously from the early 19th century to the present, indicating that the marine environment has been anthropogenically influenced since industrialization. Additionally, land reclamation, mining, and ship building activities are recorded by elevated Al/Ca ratios from 1900 to 1950. The coral record indicates that high levels of Zn, Pb and Al occur coincidentally with local wars, and may have contributed to partial colony mortality. Pb/Ca does not correlate well with hemispheric proxy records after 1950, indicating that coastal corals may be recording local rather than hemispheric contamination. Pb/Ca levels in Hong Kong, Guangdong and Hainan corals imply a continuous supply of Pb-based contamination to southern China not reflected in hemispheric signals.  相似文献   

10.
The coast of Honduras, Central America, represents the southern end of the Mesoamerican Barrier Reef System, although its marine resources are less extensive and studied than nearby Belize and Mexico. However, the coastal zone contains mainland reef formations, mangroves, wetlands, seagrass beds and extensive fringing reefs around its offshore islands, and has a key role in the economy of the country. Like most tropical areas, this complex of benthic habitats experiences limited annual variation in climatic and oceanographic conditions but seasonal and occasional conditions, particularly coral bleaching and hurricanes, are important influences. The effects of stochastic factors on the country's coral reefs were clearly demonstrated during 1998 when Honduras experienced a major hurricane and bleaching event. Any natural or anthropogenic impacts on reef health will inevitably affect other countries in Latin America, and vice versa, since the marine resources are linked via currents and the functioning of the system transcends political boundaries. Much further work on, for example, movement of larvae and transfer of pollutants is required to delineate the full extent of these links.

Anthropogenic impacts, largely driven by the increasing population and proportion of people living in coastal areas, are numerous and include key factors such as agricultural run-off, over-fishing, urban and industrial pollution (particularly sewage) and infrastructure development. Many of these threats act synergistically and, for example, poor watershed management via shifting cultivation, increases sedimentation and pesticide run-off onto coral reefs, which increases stress to corals already affected by decreasing water quality and coral bleaching. Threats from agriculture and fishing are particularly significant because of the size of both industries. The desire to generate urgently required revenue within Honduras has also led to increased tourism which provides an over-arching stress to marine resources since most tourists spend time in the coastal zone. Hence the last decade has seen a dramatic increase in coastal development, a greater requirement for sewage treatment and more demand for freshwater, particularly in the Bay Islands.

Although coastal zone management is relatively recent in Honduras, it is gaining momentum from both large-scale initiatives, such as the Ministry of Tourism's ‘Bay Islands Environmental Management Project', and national and international NGO projects. For example, a series of marine protected areas and legislative regulations have been established, but management capacity, enforcement and monitoring are limited by funding, expertise and training. Existing and future initiatives, supported by increased political will and environmental awareness of stakeholders, are vital for the long-term economic development of the country.  相似文献   


11.
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12.
This review examines the substantial changes that have taken place in marine habitats and resources of the Gulf over the past decade. The habitats are especially interesting because of the naturally high levels of temperature and salinity stress they experience, which is important in a changing world climate. However, the extent of all natural habitats is changing and their condition deteriorating because of the rapid development of the region and, in some cases from severe, episodic warming episodes.Major impacts come from numerous industrial, infrastructure-based, and residential and tourism development activities, which together combine, synergistically in some cases, to cause the observed deterioration in most benthic habitats. Substantial sea bottom dredging for material and its deposition in shallow water to extend land or to form a basis for huge developments, directly removes large areas of shallow, productive habitat, though in some cases the most important effect is the accompanying sedimentation or changes to water flows and conditions. The large scale of the activities compared to the relatively shallow and small size of the water body is a particularly important issue.Important from the perspective of controlling damaging effects is the limited cross-border collaboration and even intra-country collaboration among government agencies and large projects. Along with the accumulative nature of impacts that occur, even where each project receives environmental assessment or attention, each is treated more or less alone, rarely in combination. However, their combination in such a small, biologically interacting sea exacerbates the overall deterioration. Very few similar areas exist which face such a high concentration of disturbance, and the prognosis for the Gulf continuing to provide abundant natural resources is poor.  相似文献   

13.
Introduced marine species (IMS) can have significant impacts on economic, ecological, social and cultural aspects of coastal marine environments. There is, therefore, a need to minimise these impacts through the implementation of comprehensive and consistent management strategies and monitoring processes that work towards preventing introductions, detecting introductions if they were to occur and managing incursions should they be detected. There is also the need to ensure that approaches taken are comparable to provide consistency of IMS management effort, particularly across areas that are multi-jurisdictional (e.g. spanning State or Territory borders).  相似文献   

14.
Using meteorological data and RS dynamic land-use observation data set, the potential land productivity that is limited by solar radiation and temperature is estimated and the impacts of recent LUCC processes on it are analyzed in this paper. The results show that the influence of LUCC processes on potential land productivity change has extensive and unbalanced characteristics. It generally reduces the productivity in South China and increases it in North China, and the overall effect is increasing the total productivity by 26.22 million tons. The farmland reclamation and original farmlands losses are the primary causes that led potential land productivity to change. The reclamation mostly distributed in arable-pasture and arable-forest transitional zones and oasises in northwestern China has made total productivity increase by 83.35 million tons, accounting for 3.50% of the overall output. The losses of original farmlands driven by built-up areas invading and occupying arable land are mostly distributed in the regions which have rapid economic development, e.g. Huang-Huai-Hai plain, Yangtze River delta, Zhujiang delta, central part of Gansu, southeast coastal region, southeast of Sichuan Basin and Urumqi-Shihezi. It has led the total productivity to decrease 57.13 million tons, which is 2.40% of the overall output.  相似文献   

15.
Land resources (quantity and quality) and climate condition are two of the most important factors that regulate regional agriculture productivity. Climate and land-use have had great changes in the past decades, and hence are expected to impact crop productivity significantly. Climate change will affect crop produc-tivity through alterations of, for example, light, heat, temperature, precipitation. Land-use and land-cover change (LUCC) directly affects potential land produc-tivity by changin…  相似文献   

16.
Plans are being made to construct Dalian Offshore Airport in Jinzhou Bay with a reclamation area of 21 km2. The large-scale reclamation can be expected to have negative effects on the marine environment, and these effects vary depending on the reclamation techniques used. Water quality mathematical models were developed and biology resource investigations were conducted to compare effects of an underwater explosion sediment removal and rock dumping technique and a silt dredging and rock dumping technique on water pollution and fishery loss. The findings show that creation of the artificial island with the underwater explosion sediment removal technique would greatly impact the marine environment. However, the impact for the silt dredging technique would be less. The conclusions from this study provide an important foundation for the planning of Dalian Offshore Airport and can be used as a reference for similar coastal reclamation and marine environment protection.  相似文献   

17.
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18.
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19.
Efforts to reduce land‐based non‐point source (NPS) pollutions from watersheds to coastal waters are ongoing all around the world. In this study, annual yield of NPS nitrogen (NPS‐N) pollution in Jiaodong Peninsula, China from 1979 to 2008 was estimated. The results showed that: from 1979 to 2008, NPS‐N yields exhibited significant inter‐annual variations and an increasing trend on decadal scale. High NPS‐N yield was mainly found in east and south parts, as well as the urbanized coastal regions in Jiaodong Peninsula. Among the 32 river basins, the three largest basins yielded more than 41.16% of the NPS‐N. However, some small coastal watersheds along the South Yellow Sea and Jiaozhou Bay had higher per unit area yield. Most of the small watersheds characterized by seasonal runoff had coastal waters pertain to mild and moderate pollution levels. The ratio of watershed area to shoreline length and the up‐stream land use had significant impacts on NPS‐N flux through the shoreline. Among the four adjacent coastal areas of Jiaodong Peninsula, Jiaozhou Bay was the most noteworthy one not only because of high levels of land‐based NPS‐N pollution but also because of its nearly enclosed structure. The combination between integrated coastal zone management and integrated river basin management, land use planning and landscape designing in Jiaodong Peninsula is recommended. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

20.
Due to the reduction and degradation of coastal areas in Japan by land reclamation and anthropogenic perturbations, from the point of view of conservation of the coastal environment, the restoration of Sargassum beds is essential. Between 1978 and 1991, 6400 ha of seagrass and seaweed beds have been lost along the Japanese coast, of which Sargassum beds were 22%. New techniques for Sargassum bed restoration are summarized based on three coastal engineering techniques. (1) Construction of shallow and gentle sloping bottom substrata have been shown to be effective for the reestablishment of 'management-free seagrass and Sargassum beds' on developed coasts. (2) Seeding or transplanting using artificial substratum for extension of nursery and fishing grounds around natural Sargassum beds. (3) Periodic transplanting of Sargassum plants using artificially produced seedlings is effective to produce niches to allow faunal re-colonization in severely polluted and sparsely vegetated area. However, prior to implementation, the suitability and limitations of these three techniques requires to be ascertained for effective Sargassum bed restoration.  相似文献   

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