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1.
The objective of this study is to determine the sedimentation rate and dispersion area of calcium carbonate residue dumped at sea and the impact to marine environment of dumping by a laboratory simulation experiment; chemical tracking in the field with the help of acoustic and optical tracking; and a comparative study of baseline conditions and marine environmental impact after dumping. Turbidity, pH and phosphate are selected as the chemical tracers to be monitored.

Results show that in the dumping area of 15 square miles with water depth of 50 m, if 217 t calcium carbonate residue is dumped (spot dumping) in the presence of a pycnocline with a current velocity of 60 cm/s (close to the maximum) the maximum dispersion distance of the calcium carbonate residue plume front is less than 2100 m; the dispersion area is less than 0.56 km2; and the maximum dispersion time is about 60 min when the turbidity and pH in the whole dispersion area return to background level. Therefore, the ocean disposal of calcium carbonate residue is feasible.  相似文献   

2.
海洋酸化对鱼类感觉和行为影响的研究进展   总被引:2,自引:0,他引:2  
海洋酸化是指大气增多的二氧化碳(CO2)溶解于海水而导致海水p H值降低的过程。海洋酸化将改变海水碳酸盐平衡体系,使依赖于原化学环境的多种海洋生物乃至生态系统面临巨大威胁。海洋酸化对钙质生物影响的研究最早引起大家关注,而海洋鱼类具有较完善的酸碱调节机制,大家普遍认为酸化对其影响不大。但在过去的5年中,不少实验证明海洋酸化会影响海洋鱼类仔稚鱼的感觉和行为,减弱其野外的生存能力及增加被捕食率,很可能将威胁自然种群补给量和影响全球的渔业资源量。本文从嗅觉、听觉、视觉及高级意识和相关行为角度,综述近几年海洋酸化对鱼类感觉和行为影响的研究进展,介绍了鱼类神经行为生物学的研究,为全面了解和预测海洋酸化的生态、经济和社会效应提供科学依据。  相似文献   

3.
Increasing dissolution of anthropogenic-released carbon dioxide into the world’s oceans is causing ocean acidification (OA). OA is thought to negatively affect most marine-calcifying organisms, notably cold-water corals (CWC), which may be especially sensitive due to the deep and cold waters they normally thrive in. However, the impact of OA on CWC is difficult to predict. Recorded distributions of CWC are rarely linked to in situ water chemistry, and the boundaries of their distributions are not clearly defined. The fjord Comau in Chilean Patagonia features pronounced pH gradients, and up to 0.5 pH units have been recorded both vertically (at some sites within 50 m depth) and less distinct horizontally (from head to mouth). The cosmopolite coral Desmophyllum dianthus grows along the course of the fjord and of the entire pH range. It occurs in shallow depths (below 12 m, pH 8.1) as part of a deep-water emergence community, but also in 225 m depth at a pH of 7.4. Based on pH and total alkalinity, data calculations of the associated carbonate chemistry revealed that this CWC thrives commonly close the aragonite (the orthogonal crystal form of calcium carbonate, the mineral structure of coral skeletons) saturation horizon and even below. This suggests a high adaptation potential of D. dianthus to adjust its calcification performance to conditions thermodynamically unfavourable for the precipitation of aragonite.  相似文献   

4.
For hundreds of years, the seas have been used as a place to dispose of wastes from human activities. Although no high level radioactive waste has been disposed of into the sea, variable amounts of packaged low level radioactive wastes have been dumped at 47 sites in the northern part of the Atlantic and Pacific Oceans. in 1946 the first sea dumping operation took place at a site in the North-East Pacific Ocean. the last dumping operation was in 1982, at a site off the European continental shelf in the Atlantic Ocean. Between these two dates, an estimated 46 PBq (1.24 MCi) of radioactive waste coming from research, medical, military and industrial activities have been disposed of at sea. the present trend, through the Convention for the Prevention of Marine Pollution by Dumping of Wastes and other Matter and other Regional Conventions, points towards the prohibition of the dumping of any radioactive waste into the marine environment.  相似文献   

5.
For hundreds of years, the seas have been used as a place to dispose of wastes from human activities. Although no high level radioactive waste has been disposed of into the sea, variable amounts of packaged low level radioactive wastes have been dumped at 47 sites in the northern part of the Atlantic and Pacific Oceans. in 1946 the first sea dumping operation took place at a site in the North-East Pacific Ocean. the last dumping operation was in 1982, at a site off the European continental shelf in the Atlantic Ocean. Between these two dates, an estimated 46 PBq (1.24 MCi) of radioactive waste coming from research, medical, military and industrial activities have been disposed of at sea. the present trend, through the Convention for the Prevention of Marine Pollution by Dumping of Wastes and other Matter and other Regional Conventions, points towards the prohibition of the dumping of any radioactive waste into the marine environment.  相似文献   

6.
The calcium carbonate budget of coral reefs is the result of the interaction of the processes of calcification and biological degradation, and is reflected in the chemical properties of the seawater overlying the reefs. A series of experiments at Moorea Island (French Polynesia) in 1988 monitored the diurnal and nocturnal variations in the chemical properties of seawater under field and laboratory conditions. Our results revealed that in the study area (Tiahura barrier reef flat), the calcium carbonate budget varied over space and time as a function of location in the water current. Two in-situ sites were investigated; one was situated 100 m from the algal crest of the barrier reef, the other 300 m further downstream. As a result of cumulative upstream events, the daily net calcification was ten times higher at the downstream (5.22 gm-2 d-1) than at the upstream (0.45 gm-2 d-1) site. The carbonate uptake by in situ Porites lobata in enclosures (8 kgm-2 yr-1) was ten times higher than the uptake by the whole community in the surrounding water (0.8 kgm-2 yr-1) and five times higher than that recorded for P. lobata in laboratory experiments (1.4 kgm-2 yr-1), where illumination levels were 10% of in situ levels. In laboratory experiments, the planktonic fraction of the seawater had no perceptible influence on the calcium carbonate budget. In the absence of bioeroders, living coral totally depleted the carbonate content of the seawater (3.7 gm-2d-1). Bioerosive organisms played an important role in restoring this calcium carbonate; e.g. sea urchins grazing on algal turf covering dead coral ingested CaCO3 and released this as a carbonate powder (1.26 gm-2d-1); a form of carbonate which is extremely accessible to chemical dissolution.  相似文献   

7.
Coal fly ash (CFA) is dumped at a deep sea disposal site (1,500m water depth) in the eastern Mediterranean, ca. 70km off the Israeli shore. Since 1989, about one million tons of CFA were dumped at the 200km2 allocated area. Six years of monitoring at the dump-site shows that the CFA is heterogeneously distributed; there are areas where CFA covers about 1.3cm depth of the sea floor while at others no CFA is found. CFA is present as a fine powder, small aggregates and even as large blocks both in the dump-site as well as at its peripheries. Cadmium, copper and zinc concentrations in the CFA decreased as a result of the prolonged contact with sea water at in situ conditions while inconclusive changes in mercury, iron and manganese were detected. No changes were observed for lead, iron and aluminium concentrations. A controlled long term field experiment, now in progress at the site, is expected to clarify further chemical changes occurring in the CFA.  相似文献   

8.
In this study, we added increments of acid and base to three calcareous soils from the eastern, middle and western parts of Gansu Province (China) and to three treated soils to remove calcium carbonate, organic matter and both carbonate and organic matter, respectively. the titration curves were measured and the magnitudes of buffer capacities as a function of pH were computed. It was found that the buffer capacity of calcareous soil is mainly attributed to calcium carbonate, as expected from the chemical composition of calcareous soil, while cation exchange system, silicate buffer system and organic matter play a minor role. the results clearly show that these soils of Gansu Province will not become a problem in the near future from the entrance of H+ into these soils.  相似文献   

9.
由于大量人类活动的影响,大气CO_2浓度持续增加,其中约1/3被海洋吸收,导致表层海水pH值降低和碳酸盐平衡体系波动,即"海洋酸化"现象。污染物的海洋环境效应一直是全球环境科学领域研究的热点。在实际环境中,海洋酸化往往与污染物共同存在并作用于海洋生态系统,且海洋酸化极有可能改变污染物的海洋环境行为从而影响其毒性效应。但现有研究大多针对海洋酸化或者污染物单独作用下的毒性效应展开,对海洋酸化与污染物的联合毒性效应的研究不足、亟待加强。为此,综述了近年来海洋酸化与典型污染物(重金属、有机污染物)及新型污染物(人工纳米颗粒)的相关文献,重点阐述了海洋酸化对污染物环境行为的影响和海洋酸化与污染物对海洋生物的联合毒性效应,指出当前的研究不足,并对未来的研究方向进行了展望。  相似文献   

10.
Dredging and dumping of dredged sediments in estuarine and coastal waters may lead to increased turbidity and enhanced sediment deposition at dump sites. This mainly affects primary production by phytoplankton, performance of visual predators (e.g. fish, birds), and growth and survival of benthic organisms. This paper combines a compilation of literature information and results of additional experimental studies on the effect of enhanced concentrations of suspended matter (SPM) on growth of bivalve molluscs, and on survival of macro- and meiozoobenthos after dumping of dredged sediments. Furthermore, it focuses on non-toxic dredged sediments only. Release of nutrients from dredged sediments did, so far, hardly influence estuarine phytoplankton production. Increased turbidity may affect dab as well as prey location by sandwich terns. Enhanced SPM-concentrations are unfavourable for young herring and smelt. Growth of filter-feeding bivalves may be impaired, especially at SPM-concentrations >250 mg/l. Estuarine nematodes can survive burial by 10 cm of dumped dredged sediment provided that its physical characteristics are similar to those of the original sediment. Sessile benthos organisms such as mussels and oysters can cope with sediment deposition of only 1–2 cm. Other macrozoobenthos can survive sediment deposition of 20–30 cm. Recovery of benthos at a dump site will occur if the interval between successive dumpings is sufficiently long. Options for management of dumping of dredged sediments are described, relating to different locations of dump sites in estuarine and coastal waters, to different seasons, and to the actual use (area and frequency) of dump sites.  相似文献   

11.
Ocean acidification (OA) is beginning to have noticeable negative impact on calcification rate, shell structure and physiological energy budgeting of several marine organisms; these alter the growth of many economically important shellfish including oysters. Early life stages of oysters may be particularly vulnerable to OA-driven low pH conditions because their shell is made up of the highly soluble form of calcium carbonate (CaCO3) mineral, aragonite. Our long-term CO2 perturbation experiment showed that larval shell growth rate of the oyster species Crassostrea hongkongensis was significantly reduced at pH < 7.9 compared to the control (8.2). To gain new insights into the underlying mechanisms of low-pH-induced delays in larval growth, we have examined the effect of pH on the protein expression pattern, including protein phosphorylation status at the pediveliger larval stage. Using two-dimensional electrophoresis and mass spectrometry, we demonstrated that the larval proteome was significantly altered by the two low pH treatments (7.9 and 7.6) compared to the control pH (8.2). Generally, the number of expressed proteins and their phosphorylation level decreased with low pH. Proteins involved in larval energy metabolism and calcification appeared to be down-regulated in response to low pH, whereas cell motility and production of cytoskeletal proteins were increased. This study on larval growth coupled with proteome change is the first step toward the search for novel Protein Expression Signatures indicative of low pH, which may help in understanding the mechanisms involved in low pH tolerance.  相似文献   

12.
In order to gain preliminary knowledge about the threat to marine ecosystems due to leakage of chemical warfare agents (CWAs) and other pollutants from rusting bombshells on the seabed, a case study was conducted in a dumping area in the southern Adriatic Sea (depth 200–300 m). Following electroacoustic and magnetometric surveys of the CWA dumping area, an integrated ecotoxicological approach was used. This approach was based on analysis of CWA residues and their metabolites, including arsenic, in sediment and organisms, as well as multimarker methodology including the Health Assessment Index, histological lesion analysis and enzyme assays. Two sentinel species were selected, the blackbelly rosefish [Helicolenus dactylopterus (Delaroche, 1809)] and the European conger (Conger conger L., 1758). Sediment analysis revealed the presence of CWA degradation products, including 1-4-thioxane and 1-4-dithiane. Tissues of fish from the CWA dumping site showed higher levels of arsenic than those from the reference site. Neither CWAs nor their metabolites were detected in fish tissues. Arsenic levels recorded in blackbelly rosefish were well above those reported for other fish species from the southern Adriatic, much higher than the FDA limit for food (2.6 mg kg−1) and close to the LD50 calculated for mammals (20 mg kg−1 body weight). The presence of pollutants in the CWA dumping site was also confirmed by pathological lesions in both species and EROD activity, two to three times higher than in fish from the reference site (16.45±8.08 and 8.05±5.87 pmol min−1 mg protein−1 in blackbelly rosefish and 269±24.92 and 78.71 pmol min−1 mg protein−1 in European conger, respectively). Cholinesterase activity seemed unaffected in muscle of both species, whereas in brain they were one-third of those recorded in fish from the reference site (14.22±10.05 and 72.87 nmol min−1 mg protein−1, respectively). This suggests that acetylcholinesterase is sensitive to CWAs. In conclusion, the agreement of all the chemical and biological parameters investigated suggests that the integrated ecotoxicological approach used is appropriate to reveal the presence and biological effects of CWAs in the marine ecosystem. Physical and Chemical Impacts on Marine Organisms, a Bilateral Seminar in Italy–Japan held in November 2004.  相似文献   

13.
Coal fly ash (CFA) is dumped at a deep sea disposal site (1,500m water depth) in the eastern Mediterranean, ca. 70km off the Israeli shore. Since 1989, about one million tons of CFA were dumped at the 200km2 allocated area. Six years of monitoring at the dump-site shows that the CFA is heterogeneously distributed; there are areas where CFA covers about 1.3cm depth of the sea floor while at others no CFA is found. CFA is present as a fine powder, small aggregates and even as large blocks both in the dump-site as well as at its peripheries. Cadmium, copper and zinc concentrations in the CFA decreased as a result of the prolonged contact with sea water at in situ conditions while inconclusive changes in mercury, iron and manganese were detected. No changes were observed for lead, iron and aluminium concentrations. A controlled long term field experiment, now in progress at the site, is expected to clarify further chemical changes occurring in the CFA.  相似文献   

14.
In Italy, two different types of wastes can be dumped in the seas: industrial wastes and dredged material. There are no cases of sludges from urban treatment plants being discharged into the sea.

The sea dumping of harbour dredging sludges is a long standing practice, while the disposal of industrial wastes dates back to 1965.

Two specific laws regulate these two activities, although they do not establish quality standards for the receiving sea environment. Careful evaluation must be made, case by case, of possible effects of discharge with regard to physico-chemical characteristics of materials, to general oceanological characteristics of the dumpsite and to the uses to which such a dumpsite is designated.

The analysis of different cases of industrial waste dumping, carried out at the pre-operational level and during discharge, revealed some potential for negative long-term effects on the sea environment. This, as well as the increasing public sensitivity to environmental problems, led the management agencies in Italy to take several measures aimed to stop all forms of sea dumping of industrial wastes and to revise the general criteria in issuing permits for the discharge of dredged material.  相似文献   

15.
Seabird tracking has become an ever more popular tool to aid environmental procedures such as the designation of marine protected areas and environmental impact assessments. However, samples used are usually small and little consideration is given to experimental design and sampling protocol. European shags Phalacrocorax aristotelis were tracked using GPS technology over three breeding seasons and the following foraging trip characteristics: trip duration, trip distance, maximum distance travelled from the colony, size of area used and direction travelled from colony were determined for each foraging trip. The effect of sex, year of study, breeding site, number and age of chicks and the timing of tracking on foraging behaviour were investigated using a General Estimation Equation model. A range of sampling scenarios reflecting likely field sampling were also tested to compare how foraging behaviour differed depending on composition of the sample of birds tracked. Trip distance, trip duration, maximum distance travelled and size of area used were all significantly affected by the breeding site, and the number of chicks a tracked adult was raising. The effect of sex was also seen when examining trip distance, trip duration and the maximum distance travelled. The direction travelled on a foraging trip was also significantly affected by breeding site. This study highlights the importance of sampling regime and the influence that year, sex, age, number of chicks and breeding site can have on the foraging trip characteristics for this coastal feeding seabird. Given the logistical and financial constraints in tracking large numbers of individuals, this study identifies the need for researchers to consider the composition of their study sample to ensure any identified foraging areas are as representative as possible of the whole colony’s foraging area.  相似文献   

16.
ABSTRACT

Houzhai (Guizhou Province, Southwest China) is a typical karstification area, with dolomite and limestone constituting the major rock types. The aim of this study was to utilize major element mass-balance and multivariate statistical methods to analyze the chemical composition of water in the Houzhai River catchment area with regard to seasonal variations in ion content, dissolution reactions, and rates. Data demonstrated that the Houzhai's hydrochemical composition is dominated by calcium (Ca2+), magnesium (Mg2+), bicarbonate (HCO3?), and sulfate (SO42?) which predominantly originated from chemical weathering of carbonate rocks like limestone and dolomite. Carbonate weathering contributes 83% of the dissolved Ca2+. Sulfuric acid also plays an important role in rock weathering. Our analysis identified three principal sources of hydrochemical variation in the study area, including dolomite dissolution, limestone dissolution, and anthropogenic activities. In addition, the identified two main hydrochemical facies were characterized by the predominance of Ca-Mg-HCO3 and Ca-Mg-HCO3-SO4. In terms of temporal variation, all of the examined parameters showed strong inter-annual and seasonal variations of concentration distribution, except pH levels and potassium and sodium (K++Na+). The dissolution rate of carbonate was estimated using the concentration of Ca2+ and discharge rate, which constitutes a simple, practical, and innovative method. Compared with other research methods, our strategy was found to be simple, feasible, readily adaptable, and less demanding of data inputs.  相似文献   

17.
Impact of a kaolin clay spill on a coral reef in Hawaii   总被引:1,自引:0,他引:1  
On April 27, 1980, the Greek freighter Anangel Liberty went aground on the reef at French Frigate Shoals, a National Wildlife Refuge in the Hawaiian Islands. The vessel was refloated with no major damage or fuel spillage after 2 200 tons (2 200 000 kg) of koalin cargo had been jettisoned on the reef. Huge plumes of suspended clay raised major concern over the possibility of widespread ecological damage. However, field investigations conducted 14 d after the kaolin was dumped revealed that environmental impact waw very minor and highly localized; it was evident that most of the kaolin had been suspended and removed from the area. The only significant damage was a 2 to 3 m deep channel plowed through the reef by the freighter. Within 50 m of both sides of the channel, some coral was smothered and colonies of Pocillopora spp. were alive but slightly bleached. Beyond 50 m there were no apparent impact, nor did any clay settle on the bottom. This incident illustrates that some events which initially appear to have potential pollutant impact do not produce significant and irreversible environmental changes and emphasizes the need to analyze such events on a case-by-case basis.Hawaii Institute of Marine Biology Contribution No. 610  相似文献   

18.
Since 1985, the US Environmental Protection Agency (EPA) has conducted monitoring studies to determine the transport, fate, and effects of sewage sludge dumped at the 106-Mile Deepwater Municipal Sludge Dump Site (106-Mile Site). This paper describes EPA's 106-Mile Site monitoring activities and the results from six oceanographic surveys of the Site. Surveys have been conducted to track sewage sludge plumes and monitor dispersion and settling characteristics; study plume toxicity and contaminant levels; search for sludge and sludge constituents in surface waters in the area of the Site up 74 km (40 nautical miles) away; maintain a stationary real-time current meter near the Site; deploy and retrieve approximately 50 sediment traps and 17 current meters on 10 arrays from Hudson Canyon south to Delaware Canyon, at depths ranging from 1500 to 2800 m; and deploy satellite-tracked drifters. Results of studies completed to date have provided field data on the chemical and physical behaviour of sludge discharge plumes. Short-term persistence of sludge particles in surface waters above the pycnocline was observed and advection of sludge material from the Site may be rapid, in many cases on the order of hours. A suggestion that removal of sludge material from the surface mixed layer at the Site occurs more from horizontal mixing and advection than from vertical transport processes is supported by the data. Finally, monitoring results have provided data for assessment of permit compliance and for development of additional monitoring to detect far-field transport and long-term impacts - monitoring efforts relative to these concetns continue.  相似文献   

19.
The effects of soil pH and other soil properties on the uptake of AI by soybean plants have been investigated in a greenhouse experiment. Six soils were compared that were developed over six contrasting bedrock types ranging widely in their AI content and other chemical and physical characteristics, namely Oxford Clay, Chalk, Lower Lias Clay, Devonian Shale, Granite and Lower Greensand. Soil pH varied naturally between soil types and each soil was also amended to give two other pH levels using elemental sulphur and/or calcium carbonate. AI concentrations in various parts of the soybean plants were determined by ICP-AES after acid digestion. The AI solubility in the soils and hence its availability to the plants was estimated using a number of different reagents designed to extract different forms of AI. The AI concentration measured in the soybean leaves was found to be predicted most accurately by the ‘available’ AI extracted from soils by 0.02 M CaCl2. The relationship appears to the linear, with a correlation coefficient of 0.97 (p <0.01). The AI content of the leaves increases with decreasing soil pH. The relationship is non-linear with a marked increase in leaf AI for soils with pH <4.4. The amounts of ‘plant-available’ AI in the soils extracted with 0.02 M CaCl2 was much less than that extracted with 0.05 M EDTA, although both increased markedly with decreasing soil pH. The amount of AI measured in the soybean plants was directly related to both the ‘available’ forms of AI in the soils, and also to the pH of the soils. Soil pH was identified as a major factor that controls the uptake of Al from soil into the soybean plant.  相似文献   

20.
Calcium carbonate is used in large amounts in the pulp and paper industry as a paper filler. When it is manufactured, the calcium carbonate waste is purged from the process. Here we demonstrate that, due to the elevated calcium concentration of 168.5 g kg−1 dry weight (dw), alkaline pH of 12.6 and neutralizing (liming) effect value of 42.4% expressed as Ca equivalents, this waste is a potential liming agent and a pH buffer. The heavy metal concentrations in the waste were lower than the new Finnish limit values for fertilizers used in agriculture, as well as for a material, e.g. ash, used as an earth construction agent. These limit values came into force in March 2007 and in June 2006, respectively.  相似文献   

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