互花米草盐沼土壤有机质分布特征

互花米草是我国从美国引进的外来物利，目前在我国沿海已形成大面积的互花米草盐沼，对潮滩土壤等环境产生重大影响。为了分析互花米草盐沼土壤有机质的分布特征，本文通过对江苏东台沿海不同地点(生长年数)的互花米草盐沼土壤样品的-仃机质含量分析，发现互花米草盐沼在由海堤向外的水平方向上变化的平均梯度为每100m土壤有机质含最减少0.87g/kg，垂直方向上的平均梯度为每向下1cm土壤有机质含量减少0.05g/kg。互花米草盐沼土壤订机质的含量与互花米草生长年数相关程度较高，而与植株的生长状况相关较低。     

The Distribution of Talitrid Amphipods (Crustacea) on a Salt Marsh in Southern Tasmania, in relation to Vegetation and Substratum

Supralittoral and terrestrial talitrid amphipods were collected from a salt marsh in Southern Tasmania by pitfall trapping along transects from the mid-tidal level to above the high-tide mark, and by hand collecting from sites chosen to represent the full range from salt marsh to terrestrial vegetation. At each site, the cover of all major plant species was recorded, and soil samples were collected from which soil moisture, organic content and salinity were measured.Eight talitrid species from four ecological groups were collected; one palustral species, one beachflea, three coastal landhoppers and three eastern forest landhoppers. There was substantial overlap in the distributions of these groups. The undescribed beachflea had the widest distribution, from the wettest, most saline sites to theSchoenus nitenstussock grassland at the extreme high-tide mark. The palustral species,Eorchestia palustris, overlapped substantially with the beachflea, but was found within a narrower band of salinities (though not in the most saline sites) and in more poorly-drained sites than the beachflea. Coastal landhoppers,Austrotroides maritimus,Keratroides rexand an undescribed species ofTasmanorchestia, were found mainly in theS. nitenstussock grassland, where they overlapped with forest landhoppers,Keratroides vulgaris,Mysticotalitrus tasmaniaeandM. cryptus, which were found mainly in non-saltmarsh terrestrial sites, well above the high-tide mark.These distributions are discussed in terms of the likelihood that salt marshes provided the route by which talitrid amphipods colonized land. There is no reason from these data to reject salt marshes as the route to land, and it is suggested that they are a more likely route than via rocky or sandy shores.     

Importance of Vascular Plant and Algal Production to Macro-invertebrate Consumers in a Southern California Salt Marsh

The dietary importance of marsh vascular plants (primarilySalicornia virginica), algae and upland particulate inputs to macro-invertebrate consumers was studied in Carpinteria Salt Marsh, southern California, using stable carbon and nitrogen isotope ratios. This marsh is predominantly a marine or hypersaline system and succulents are the most common vascular plant species. Of invertebrates collected from the vegetated marsh, tidal flats and channels, only detritivores from the vegetated marsh (Traskorchestia traskiana,Melampus olivaceus) had isotope values (δ¹³C=−20‰) that suggested some use ofSalicornia-derived carbon.T. traskianacultured in the laboratory on decomposingS. virginicaor blue-green micro-algal mat had distinctive isotopic signatures, reflecting the capability of this consumer to assimilate carbon and nitrogen derived from these sources. The δ¹³C values (generally −16‰ to −15‰) of species from tidal flats and channels (e.g.Cerithidea californica,Protothaca staminea,Mytilus galloprovincialis,Neotrypaea californiensis) were most similar to values for benthic algae and phytoplankton. Specimens ofM. galloprovincialisalong a gradient of presumed increase in marine influence had similar isotope values, suggesting little contribution to diet from upland runoff. The present results differ most noticeably from published values in the¹³C enrichment of suspension-feeders, suggesting the use of resuspended¹³C-enriched benthic microalgae in tidal channels by these consumers, and in the¹³C depletion and¹⁵N enrichment of plants and consumers along a portion of the marsh boundary receiving inputs of nutrient-enriched perched groundwater. In general, the isotopic composition of macro-invertebrates indicated the incorporation of algal production rather than ofS. virginicaor upland sources into the marsh food web.     

2012年秋季白脊管藤壶在江苏如东互花米草盐沼向附着及分布

互花米草Spartina alterniflora自1979年引入至今,已在我国海岸带大范围扩张并对盐沼湿地生态系统产生了很大影响.本研究以附着生物藤壶为例,研究了互花米草扩张对附着生物的影响.通过对5个断面共28个样方的米草植株、附着藤壶以及藤壶在互花米草上的最大附着高度调查,获得结果如下:藤壶在互花米草滩上的附着范围位于潮沟两侧,且呈宽度约为5 m的带状分布;潮沟规模越大,其向陆方向的延伸范围越宽;每个站位藤壶附着的相对最大高度都位于同一水平.附着藤壶均为白脊管藤壶Fistulobalanus albicostatus,平均干重237±69g·m-2,大部分藤壶直径在2～10mm之间.互花米草的平均干重为981±81g·m-2,潮沟附近互花米草高壮但密度较小,远离潮沟互花米草矮小但密度较大.分析表明,互花米草为藤壶提供了附着基质,并影响藤壶在潮间带的平面分布格局(尽管藤壶的生态位保持不变).影响白脊管藤壶分布特征的原因主要是海水浸没时间的差异;负地形的浸没时间更有利于藤壶的附着和生存;另外潮沟较高的潮水流速除了利于白脊管藤壶幼体的附着外,还可以通过水流的涨、落为其带来充足的食物.     

美国岸线现状调查30年进展综述——以美国弗吉尼亚州为例

以美国弗吉尼亚州20世纪70年代和21世纪初两个年代进行的岸线现状调查工作为例,介绍了30年来美国岸线现状调查的目标、指导原则、调查内容、数据来源、报告编写等内容,并与我国20世纪80年代开展的"全国海岸带和海涂资源综合调查"工作以及当前正在开展的"我国近海海洋综合调查与评价"专项的海岸带调查进行了对比,讨论了两国在海岸带调查方面的异同,以及可供借鉴之处。     

Accretion of a New England (U.S.A.) Salt Marsh in Response to Inlet Migration, Storms, and Sea-level Rise

Sediment accumulation rates were determined at several sites throughout Nauset Marsh (Massachusetts, U.S.A.), a back-barrier lagoonal system, using feldspar marker horizons to evaluate short-term rates (1 to 2 year scales) and radiometric techniques to estimate rates over longer time scales (¹³⁷Cs,²¹⁰Pb,¹⁴C). The barrier spit fronting theSpartina-dominated study site has a complex geomorphic history of inlet migration and overwash events. This study evaluates sediment accumulation rates in relation to inlet migration, storm events and sea-level rise. The marker horizon technique displayed strong temporal and spatial variability in response to storm events and proximity to the inlet. Sediment accumulation rates of up to 24 mm year⁻¹were recorded in the immediate vicinity of the inlet during a period that included several major coastal storms, while feldspar sites remote from the inlet had substantially lower rates (trace accumulation to 2·2 mm year⁻¹). During storm-free periods, accumulation rates did not exceed 6·7 mm year⁻¹, but remained quite variable among sites. Based on¹³⁷Cs (3·8 to 4·5 mm year⁻¹) and²¹⁰Pb (2·6 to 4·2 mm year⁻¹) radiometric techniques, integrating sediment accumulation over decadal time scales, the marsh appeared to be keeping pace with the relative rate of sea-level rise from 1921 to 1993 of 2·4 mm year⁻¹. At one site, the²¹⁰Pb-based sedimentation rate and rate of relative sea-level rise were nearly similar and peat rhizome analysis revealed thatDistichlis spicatarecently replaced this onceS. patenssite, suggesting that this portion of Nauset Marsh may be getting wetter, thus representing an initial response to wetland submergence. Horizon markers are useful in evaluating the role of short-term events, such as storms or inlet migration, influencing marsh sedimentation processes. However, sampling methods that integrate marsh sedimentation over decadal time scales are preferable when evaluating a systems response to sea-level rise.     

Daily and inter-tidal variations of Fe,Mn and Hg in the water column of a contaminated salt marsh: Halophytes effect

It has been shown that salt marshes may function as efficient sinks for contaminants, namely for mercury. At the rhizo-sediment Hg may be associated with Mn and Fe oxyhydroxides, precipitated as sulphides or incorporated into organic matter. However, to our knowledge, in situ studies have not focused on the related processes at a daily or tidal cycle scales. Thus, the present work aims to study the effect of a common salt marsh halophyte in temperate latitudes (Sarcocornia perennis) on dissolved Fe, Mn and Hg concentrations in the water column. The in situ approach was carried out at a mercury-contaminated salt marsh and at the adjacent non-vegetated area (distance ≤ 4 m), covering two consecutive tidal cycles in order to include the photosynthetic active period and the night processes. During high tide no daily or spatial effects were observed on the concentrations of Mn, Fe and Hg in the water column, due to the dilution effect of the incoming seawater. During low tide the concentrations of Mn, Fe and Hg were significantly higher in the overlaying water column of the salt marsh. At S. perennis mats the concentration of dissolved total Hg was significantly related with the concentration of Mn (r = 0.459, p = 0.028, n = 23), but not with that of Fe (r = 0.367, p = 0.085, n = 23) while no significant relations were found at the adjacent non-vegetated sediments.     

Biomass Production in PioneerSpartina anglicaPatches: Evidence for the Importance of Seston Particle Deposition

Salt marsh formation can be initiated by the colonization of bare tidal flats by pioneer halophytes such asSpartina anglica. In the present study, growth ofS. anglicain the edge and centre zones of pioneer patches colonizing a tidal flat in a marine bay in the south-west Netherlands was investigated. Average biomass and shoot length was significantly lower in centre zones than in edge zones of the patches. Multiple linear regression showed that 84% of the variance in aboveground biomass in the centre zones could be explained by sediment phosphorus and nitrogen concentrations. No such relationship existed in the edge zone. This suggests that biomass production in the centre zones of the patches is nutrient limited, but that factors other than sediment nitrogen and phosphorus content determine growth ofSpartinain the edge zones.The sediment nitrogen and phosphorus concentrations in the centre zones of the patches were significantly related with sediment carbon concentrations, indicating that the pool of particle-bound nutrients in the sediment to an important extent is associated with organic particles. Determination of stable carbon isotope signatures of the sedimentary organic matter showed that an increasing carbon content of the sediment in the centre zone of the patches (and a rise in plant biomass) coincides with a higher contribution of non-Spartinaderived carbon to the sedimentary organic matter pool. Sustained biomass production in the centre zones of the patches, thus, probably depends on deposition of allochthonous organic particles and the nutrient inputs inherent in this process. Due to the construction of large-scale hydro-engineering works, however, conditions for deposition of waterborne particles are currently unfavourable. The consequences of reduced carbon and nutrient inputs into the patches will be particularly in the (older) centre zones, where the nutrient pools in non-refractory organic matter have been drained in the years of previous growth. Accordingly, it is hypothesized that the canopy-enhanced sedimentation for whichSpartinais well- known, via positive feed-back effects on plant growth can be crucial for plant vitality, and, hence, for successful colonization of unvegetated areas.     

Spatial and temporal variations in sediment grain size in tidal wetlands, Yangtze Delta: On the role of physical and biotic controls

To examine the spatial and temporal variability of sediment grain size in exposed tidal wetlands with ample sediment supply, we sampled sediments and measured hydrodynamics, accretion/erosion rates, and vegetation characteristics in the Yangtze Delta. Sediment grain size exhibited a landward/upward decreasing trend. This trend is mainly attributed to attenuation of hydrodynamics. A 630-day series of daily surface sediment sampling at a fixed site on an unvegetated intertidal flat revealed significant seasonal and storm-cyclic changes in grain size. This temporal variability was related to alternating accretion/erosion events, with erosion associated with coarser grain size. Such temporal dynamics were not present in vegetation, where sediment remained fine grained throughout the year. In the marsh, vegetation cover enables the trapping of fine-grained sediments in the following ways: (a) adherence of suspended sediments onto plants; (b) deposition of suspended sediments stimulated by attenuation of hydrodynamics through plant obstruction; and (c) prevention of resuspension of fine-grained deposits due to the protection of the plant canopy. The influence of vegetation on sediment grain size was clearly seen when comparing sediment trapped by different vegetation types and seasonal patterns of trapped sediment on different vegetation canopy densities. The relatively high plant biomass of the recently introduced Spartina alterniflora enhanced the trapping effect, whereas plant degradation due to buffalo grazing reduced the trapping effect. We conclude that for exposed tidal wetlands with ample sediment supply such as the Yangtze Delta, the spatial and temporal variability of sediment grain size is governed predominantly by physical controls on the unvegetated flat and predominantly by biophysical interaction of hydrodynamics and vegetation in the salt marsh, rather than by sediment supply.     

Understanding and contextualizing social impacts from the privatization of fisheries: An overview

Fisheries management around the world has experimented with regulations to promote privatization, in order to reach such multifaceted goals as ending overfishing and reducing economic inefficiencies. This review surveys a wide range of empirical experiences in different contexts around the world to help provide a fuller picture of potential and sometimes disparate consequences from privatization in general and new ways of organizing around fishing that can follow in the wake of such measures. Looking at the many different participants in the fishing industry—from crew, small-boat owners, to households and communities—as well as the diverse sociocultural contexts in which fishing takes place, enables a better understanding of who and what is impacted, how they are impacted, why and with what further consequences, such that communities come to be seen less oppositional to economy, but rather constituted by multiple scalar processes and by economic relations comprising different motivations and behaviors.     

Salt tectonics and Pliocene stratigraphic framework at MC-118, Gulf of Mexico: An integrated approach with application to deep-water confined structures in salt basins

Integrated tectono-stratigraphic interpretation at MC-118 using 3D seismic, well logs and biostratigraphy reveals an area dominated by allochthonous salt and its related structures. OCS-Block MC-118 is located 130 km southeast of New Orleans on the Gulf of Mexico middle slope in ∼2600 ft of water.The area is divided into three domains based on their structural styles: (1) a western domain consisting of a basinward-dipping normal fault family and associated strata; (2) a central domain composed of a landward-plunging diapiric salt tongue canopy and associated salt welds, two flanking NE–SW trending salt-withdrawal mini-basins, and a crestal fault family; and (3) an eastern domain comprised of basinward/landward-dipping normal and listric normal fault families with their associated rollovers. These structural domains are genetically-and-kinematically related to the salt structure and extend beyond MC-118 boundaries. The salt structure is postulated to have evolved mostly passive, with punctuated active episodes, and by lateral spreading. This is part of a larger regional structure, eastern Gulf of Mexico, which involves some amalgamation between small-scale salt canopies and salt diapirs although collectively they appear mostly disconnected.A Pliocene (3.13–4.95 Ma) third-order genetic stratigraphic sequence, the focus of this study, is as much as ∼3600 ft thick within the mini-basins and contains: muddy mass transport complexes; sandy slope fans; muddy turbidites and condensed sections; and transitional facies flanking the salt structure that collectively have ponded and wedged external geometries. Mass transport complexes and muddy turbidites and condensed sections make most of the studied genetic sequence in a mud-dominated deltaic setting eastern Gulf of Mexico.Facies kinematic indicators and a matching number of genetic sequences accounted on the sea level chart support a eustatically driven mini-basin sedimentation. Nonetheless salt still plays a role in sedimentation (secondary/minor) by slumping generated during passive/active salt diapiric evolution.     

An Examination of the Fluxes of Nitrogen and Phosphorus in Temperate and Tropical Estuaries: Current Estimates and Uncertainties

In a number of regions of the world, enhanced flows of nitrogen (N) and phosphorus (P) from land to sea are of major concern because of the observable deterioration in the quality of many nearshore marine waters. Estuaries receive N and P from river and other runoff, from waste discharges, from the atmosphere and ocean and from exchange with coastal groundwaters (which in all likelihood results in a net input to the estuary). For rivers that do not discharge directly onto the continental shelf, seaward fluxes of N and P will be modified by within-estuary transformations of reactive species, the burial of particulate N and P in sediments (sub/intertidal, saltmarsh, mangrove) and the loss of gaseous N and P species by bacterial reduction.Driven by a desire to understand the effects of changing N and P loads on water quality, and to gain insights into the true modification of their fluxes within estuaries, much effort has been expended on providing quantitative estimates of the sources and sinks of these constituents. Yet, accurate and precise estimates on a global scale remain elusive. Riverine inputs of total N and P are calculated to be 35–64 and 22 Mt a⁻¹, respectively. These inputs are dominated by particulate species, and because of this, are likely to be imprecise as overall sediment fluxes are disproportionately influenced by infrequent, poorly sampled, high flow events. Direct aeolian inputs of N to estuaries (P inputs are minor), at a minimum of 1–4 Mt a⁻¹, are small but significant, although again good estimates are hampered by the apparent importance of infrequent, and thus under-sampled, deposition events. Indirect atmospheric inputs via deposition onto and runoff from catchments may be highly significant, at least in environments bounding the North Atlantic Ocean. Groundwater inputs are generally unknown, but, for N, may be 5–10 Mt a⁻¹ (no data on P). Information on the global inputs of N and P from waste discharges and mariculture do not appear to be available. Denitrification, estimated to beca . 33 Mt a⁻¹, may account for 52–94% of the currently estimated total N inputs; in contrast, the loss of P via venting of gaseous phosphine is unknown. The burial of N and P in sediments is about 7% and 30% of their total inputs, respectively. Nevertheless, reliable information on the modifying role of estuarine sediments appears far from complete.Globally, the inputs of N and P to the marine environment from all sources are expected to increase over the next few decades. The resulting effects of these increases on the marine environment, including any influences due to estuarine processing, may be partly assessed through the use of dynamic transport and transformation estuarine models for N and P. A further important development in this respect will be the linking of complementary models (e.g. catchment/river/estuarine/coastal zone) and their coupling to strategic large scale observations.     

Prospects for the use of macro-algae for fuel in Ireland and the UK: An overview of marine management issues

Competing demand for land is driving biofuel and bioenergy research in various directions including macro-algae (seaweed). This paper reviews the main issues for the marine environment of cultivating and harvesting UK and Irish seaweed for biofuels/bioenergy, informed by stakeholder interviews. These showed stakeholders were sceptical of an offshore cultivation industry developing but generally considered inshore cultivation possible, while noting various practical obstacles and conditions. Views on expansion of seaweed harvesting were more divided, with research scientists being relatively cautious.     

Fish harvest tags: An alternative management approach for recreational fisheries in the US Gulf of Mexico

This paper explores the potential adaptation of harvest tags to the Gulf of Mexico recreational reef fish fishery. The discussion addresses conceptual, theoretical, and practical issues surrounding the application of harvest tags, as well as challenges and opportunities related to the design of tag programs. A review of hunting and fishing tag programs around the world and analysis of Gulf recreational fisheries suggests that tags have the potential to improve control over total catches, increase economic benefits and provide better information for fishery management. Results also provide insight into potential use of fish tags in large-scale recreational fisheries nationwide.     

Structural regime and its impact on the mechanism and migration pathways of hydrocarbon seepage in the southern Gulf of Suez rift: An approach for finding new unexplored fault blocks

A Natural active oil seepage occurs at the intersection of the NW-oriented rift coastal fault and a NE-oriented cross fault which bound the southwest dipping Little Zeit tilted fault block at the southwestern side of the Gulf of Suez, Egypt. Detailed surface geological mapping followed by subsurface mapping using aeromagnetic, seismic and borehole data of Ras El Ush oilfield (the nearest oil field to the seepage) provide a reliable hydrocarbon migration pathway model of the area.The proposed model suggests that hydrocarbons migrated upward at the intersection of a NE-oriented and the NW-oriented rift coastal faults where they found their way to the surface. The Nubia Sandstone occurs south of Ras El Ush oilfield in a trap door structure and probably entrapped some of the migrating hydrocarbons while a probable oil-water-contact at −1000 m which resulted into the migration of hydrocarbon through the damage zone of the northeast fault.The original oil in place of the predicted reservoir is estimated to be more than 47.5 MMBO which encourages the design makers for more investigation of this reservoir to increase its certainty and putting it in the plan of the future investments.