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101.
河口潮汐湿地沉积物电子受体和盐度的变化将对间隙水、沉积物的地球化学参数及有机碳厌氧矿化途径产生重要影响.本研究于闽江河口塔礁洲淡水野慈姑(Sagittaria trifolia L.)湿地原位施加人造海水及Fe(III)溶液,模拟研究了盐水入侵及径流Fe(III)浓度增强对河口潮汐湿地沉积物、间隙水的地球化学参数(溶解性CH4、DOC、DOC∶DON、Fe2+和ΔSO2-4)和沉积物各形态固相铁(非硫Fe(II)、无定形Fe(III)、晶质Fe(III)、Fe S和Fe S2)含量的影响.结果表明,模拟盐水入侵及径流Fe(III)浓度增强均可降低间隙水溶解性CH4和DOC浓度,径流Fe(III)浓度增强增加了非硫Fe(II)和晶质Fe(III)含量,盐水入侵可减小间隙水ΔSO2-4含量.间隙水ΔSO2-4与DOC、DOC∶DON、溶解性CH4及Fe2+浓度相关.模拟盐水入侵及径流Fe(III)浓度增强可分别促进硫酸盐异化还原和铁异化还原速率,同时减小间隙水CH4浓度,改变河口潮汐湿地土壤有机质厌氧矿化优势途径. 相似文献
102.
Eelgrass (Zostera marina L.) in the Dutch Wadden Sea historically covered an area varying from 65–150 km2 in the eulittoral as well as the sublittoral zones. At present, this area comprises less than 1 km2 eulittoral eelgrass stands, with an associated decrease in habitat diversity. The causes for this decline are presumably
connected with the ‘wasting disease’ and the closure of the former Zuiderzee in the early 1930s resulting in increased tidal
range and increased currents. After a slight recovery of the eelgrass populations on the intertidal flats a definite decline
started in the early 1970s, possibly connected to increased turbidity. The present water quality and turbidity do not negatively
influence eelgrass growth up to a depth of at least 0.6m below Mean Sea Level. Based on mesocosm experiments and field experiments
it is concluded that re-establishment of eelgrass should be possible in sheltered bays and on unexposed tidal flats. The most
suitable depths for a reintroduction are those between 0 and 20–40 cm below mean sea level. 相似文献
103.
Eddy van der Maarel Marijke van der Maarel-Versluys 《Journal of Coastal Conservation》1996,2(1):73-92
A comprehensive list of 1068 typical littoral plant species and subspecies has been composed. They are considered endemic
in a wide sense and are subdivided into widespread, transregional, regional and local endemics, the latter three categories
being considered as endemics s.s. For each taxon the distribution, habitat preference, endemic status and conservation status
are given. The list, which is available upon request, is summarized in a number of figures and tables, from which it appears
that 61% of all species are endemics s.s., that ca. 30% of all species are dune and beach species and another nearly 30% are
maritime rock species. Species of wet habitats are concentrated in northern and northwestern Europe, dune species in western
and southwestern Europe, western Mediterranean and Black Sea. The conservation status of most species is indicated; 37% is
considered threatened. It is concluded that the Bern Convention and the European Habitat Directive offer an entirely insufficient
framework for effective conservation action. It is suggested to take the present list as a starting point for a geographical/taxonomical/ecological
data base of European coastal endemics. 相似文献
104.
‘Coastal squeeze’— an historical perspective 总被引:1,自引:0,他引:1
J. Pat Doody 《Journal of Coastal Conservation》2004,10(1):129-138
The use of salt marsh for agricultural use has probably been going on for thousands of years. This paper will look at the situation in southeast England, particularly the Wash. Here enclosure for extended grazing and over the last several hundred years, for arable cultivation, may have taken place since Roman Times. An enclosure of Freiston Shore salt marsh (1979) and a proposed further enclosure at Gedney Drove End at about the same time raised concerns about the cumulative effect of these developments on nature conservation interests. These concerns prompted the nature conservation agencies to oppose the Gedney Drove End enclosure. Though the conservation argument did not persuade the Government that no further enclosure should take place, economic circumstances changed such that the pressure for the creation of new agricultural land diminished. This marked the end of ‘reclamation’ in the Wash. Since then, in the UK at least, there have been no further enclosures of salt marsh for agriculture. What were the arguments that lead to this change? Up to this point the perceived wisdom, in the Wash at least, was that as enclosure took place new inter-tidal land was created to seaward— with no net loss of inter-tidal land. Today we accept that this is not the case and a policy of managed re-alignment has increasingly been adopted in England, at sites ranging from the Porlock shingle ridge in north Devon to the salt marshes of Freiston in the Wash. It is argued that recognition of ‘coastal squeeze’ probably began in the Wash some 20 years ago. It would appear that we are now witnessing a reversal of this trend. How far will it take us? Will we see a return of the large expanses of tidal swamp around the Wash and elsewhere along the southern North Sea coast? Is this an inevitable consequence of global warming? This paper provides an historical perspective of the issues and arguments that have led us to recognize ‘coastal squeeze’ and the importance of dynamic coast, including the European Commission’s ‘EURosion Project’, which reported in 2004 (Salman et al. 2004). 相似文献
105.
106.
Eelgras (Zostera marina L.) in the Dutch Wadden Sea historically covered an area varying from 65–150 km2 in the eulittoral as well as the sublittoral zones. At present, this area comprises less than 1 km2 eulittoral eelgrass stands, with an associated decrease in habitat diversity. The causes for this decline are presumably
connected with the ‘wasting disease’ and the closure of the former Zuiderzee in the early 1930s resulting in increased tidal
range and increased currents. After a slight recovery of the eelgrass populations on the intertidal flats a definite decline
started in the early 1970s, possibly connected to increased turbidity. The present water quality and turbidity do not negatively
influence eelgrass growth up to a depth of at least 0.6m below Mean Sea Level. Based on mesocosm experiments and field experiments
it is concluded that re-establishment of eelgrass should be possible in sheltered bays and on unexposed tidal falts. The most
suitable depths for a reintroduction are those between 0 and 20–40 cm below mean sea level. 相似文献
107.
Salinization and sodicity are obstacles for vegetation reconstruction of coastal tidal flat soils. A study was conducted with flue gas desulfurization(FGD)-gypsum applied at rates of 0, 15, 30, 45 and 60 Mg/ha to remediate tidal flat soils of the Yangtze River estuary.Exchangeable sodium percentage(ESP), exchangeable sodium(ExNa), p H, soluble salt concentration, and composition of soluble salts were measured in 10 cm increments from the surface to 30 cm depth after 6 and 18 months. The results indicated that the effect of FGD-gypsum is greatest in the 0–10 cm mixing soil layer and 60 Mg/ha was the optimal rate that can reduce the ESP to below 6% and decrease soil p H to neutral(7.0). The improvement effect was reached after 6 months, and remained after 18 months. The composition of soluble salts was transformed from sodic salt ions mainly containing Na~+, HCO_3~-+ CO_3~(2-)and Cl-to neutral salt ions mainly containing Ca~(2+)and SO_4~(2-). Non-halophyte plants were survived at 90%. The study demonstrates that the use of FGD-gypsum for remediating tidal flat soils is promising. 相似文献
108.
Muh Aris Marfai Lorenz King Junun Sartohadi Sudrajat Sudrajat Sri Rahayu Budiani Fajar Yulianto 《The Environmentalist》2008,28(3):237-248
The article presents household vulnerability, local community adaptive capacity, and government’s response to tidal flood
hazard in the Semarang coastal area, Central Java Province, Indonesia. Using data gathered from a survey of households, the
study revealed a number of important factors about the interaction between people and flood. The coastal community has been
experiencing problems related to tidal floods. They have adapted to tidal flooding with structural measures, such as increasing
the floor level, making small dams in front of houses, increasing yard and street levels in the neighborhood area, and creating
dykes around residential areas. Tidal flood mitigation in the Semarang coastal area should incorporate governmental action
and local community capacities for proper protection of the population. 相似文献
109.
Direct measurement of denitrification activity in a Gulf coast freshwater marsh receiving diverted Mississippi River water 总被引:1,自引:0,他引:1
Wetland loss along the Louisiana Gulf coast and excessive nitrate loading into the Gulf of Mexico are interrelated environmental problems. Nitrate removal by soil denitrification activity was studied in a ponded freshwater marsh receiving diverted Mississippi River water for the purpose of reversing or slowing wetland loss. Labeled 15N-nitrate was applied at 3.8 g N m−2 into four replicate study plots after removing above ground vegetation. Nitrogen gas (N2) and nitrous oxide (N2O) emissions from the plots were determined by isotope ratio mass spectrometry (IRMS). Nitrous oxide emissions were also compared with the results determined by gas chromatograph (GC). Results showed that it took 2 weeks to remove the added nitrate with N2O emission occurring over a period of 4 d. The apparent denitrification dynamics were assumed to follow the Michaelis–Menten equation. The maximum denitrification rate and Km value were determined as 12.6 mg N m −2 h−1, and 6.5 mg N l−1, respectively. Therefore the maximum capacity for nitrate removal by the marsh soil would be equivalent to 110 g N m−2 yr−1, with more than 30% of nitrogen gas evolved as N2O. For typical nitrate concentrations in Mississippi River water of about 1 mg N l−1, nitrate would be removed at a rate of 14.7 g N m−2 yr−1 with N2O emission about 1.5%. A denitrification dynamic model showed that the efficiency of nitrate removal would largely depend on the water discharge rate into the ponded wetland. Higher discharge rate will result in less retention time for the water in the marsh where nitrate is denitrified. 相似文献
110.
滨海潮滩沉积物铁异化还原过程对有机质代谢及生源要素(C、N、P、S、O等)生物地球化学循环具有深远的影响.本文以闽江河口鳝鱼滩潮滩湿地为研究对象,对高、中、低潮滩0~80 cm深度内与铁异化还原相关的不同形态铁的含量和空间分布进行分析.结果表明,无定形Fe(Ⅲ)((39.3±5.3)μmol·g~(-1))和晶质Fe(Ⅲ)((84.2±10.7)μmol·g~(-1))主要分布在高潮滩,并沿着向海方向减少;铁的硫化物FeS((15.3±2.8)μmol·g~(-1))和Fe S2((6.0±1.1)μmol·g~(-1))集中分布在中、低潮滩;非硫Fe(II)((111.7±12.8)μmol·g~(-1))富集在整个潮滩剖面上,且含量随着深度增加而增加.孔隙水Fe~(2+)((3.7±0.7)mmol·L~(-1))与Fe S2、SO_4~(2-)和pH相关,说明Fe~(2+)可能与黄铁矿的水解有关.不同形态铁在高、中、低潮滩表现出显著的空间分布异质性.高潮滩铁异化还原的强度大于硫酸盐异化还原,但沿着向海方向,硫酸盐异化还原的潜势逐渐增加.本研究证明了潮汐水文和高程对潮滩湿地铁的迁移和转化具有重要的意义. 相似文献