中国河口湿地研究现状及展望

河口湿地由于其发育和形成过程较为特殊,加上其丰富的动植物资源以及重要的经济地位,已成为我国湿地研究领域的一个新热点.本文在分析中国河口湿地分布与特征的基础上,从河口湿地生物多样性、河口湿地生态过程及动态变化、河口湿地的形成和发育机制、河口湿地景观格局及动态演变、河口湿地恢复与重建、河口湿地的人地关系、河口湿地与全球变化、河口湿地评价以及数字河口湿地建设等方面总结了我国河口湿地研究现状.尽管中国河口湿地研究的方向和成果已经比较丰富,但与国外相比,在技术和理念上还存在一定差距.结合国外河口湿地研究的最新动态,提出了中国河口湿地未来研究的4个重要方向：河口湿地的人地关系、河口湿地的恢复和重建、河口湿地与全球变化以及河口湿地综合信息系统建设.     

A benthic perspective in assessing the ecological status of estuaries: The case of the Mondego estuary (Portugal)

In transitional waters the process of defining reference conditions (in the scope of the WFD) must account for the natural great variability of such environments. Therefore, stretches reflecting different physical–chemical and biological conditions throughout the system should be defined in order to correctly establish benthic specific reference conditions. Both salinity and sediment structure are major factors controlling physical–chemical conditions and therefore organisms’ distribution within an estuary. These environmental variables (salinity, sediment grain size composition and organic matter content) patterns were studied in the Mondego estuary and some clear gradients emerged. Also, ecological indices (AMBI, Margalef and Shannon-Wiener) were applied to subtidal benthic communities of the Mondego estuary and, generally, there was not only evidence of a decrease in diversity in the estuary from the downstream section towards its inner parts, but also differences were found between areas of distinct sediment composition. After comparing environmental patterns with biodiversity trends, the information was used to define homogeneous sectors along a temperate estuary in Portugal. In the Mondego estuary six zones, covering the main physical gradients affecting benthic communities, were defined: four in the northern arm and two in southern arm. Zones established will allow future determination of benthic reference conditions adjusted for each of the sectors, according to their characteristics, and consequently the conditions they provide for benthic assemblages settlement.     

Fish habitat use response to anthropogenic induced changes of physical processes in the Elwha estuary, Washington, USA

The Elwha River estuary has been significantly influenced by anthropogenic changes to the river, including two large dams upriver and rock dikes installed in the estuary. Together these have disrupted hydrodynamic processes and subsequent sediment delivery throughout the watershed. This article defines the functional response of fish distribution within the estuary as a result of these changes. We assessed fish distribution of three main areas of the Elwha estuary using standard beach seining techniques from March to August 2007. Species composition, ecological indices, and relative proportion of all salmonids, and in particular Chinook salmon (Oncorhynchus tshawytscha), were consistently significantly different across the estuary. Differences corresponded to a rock dike installed 30 years ago, and a sediment lens that was observed to form at the entrance to the east estuary. Sediment lenses are documented to be a common occurrence in the Elwha nearshore, and symptomatic of documented, severely disrupted sediment processes of the Elwha River. Combining the fish distribution documented in this study with the rock dike and observed sediment lens and the sediment processes documented by other researchers we, therefore, conclude: (1) Fish use within the Elwha River estuary is complex, and even fragments of connected estuary are critically important for migrating salmon; (2) Anthropogenic effects, including in river damming and diking of the estuary, can be an important ecological driver in nearshore habitat function that should be appropriately considered in estuary habitat research, management, and restoration; and (3) Juvenile salmonids appear to be able to respond to dynamic sediment environments if there are habitat options available.     

USING QUANTITATIVE PCR TO DETERMINE THE DISTRIBUTION OF A SEMICRYPTIC BENTHIC DIATOM,NAVICULA PHYLLEPTA (BACILLARIOPHYCEAE)1

Evidence has accumulated during the last decade showing that many established diatom morpho‐species actually consist of several semicryptic or truly cryptic species. As these species are difficult or even impossible to differentiate by microscopic analysis, there is virtually no information on how they behave in natural environments. In this study, we developed a quantitative real‐time PCR (qPCR) assay using TaqMan probes^® targeted to the internal transcribed spacer 1 (ITS1) to assess the spatial distribution and seasonal dynamics of an important component of the microphytobenthos of intertidal sediments. Navicula phyllepta Kützing is a brackish‐marine morpho‐species with a cosmopolitan distribution. Axenic clones of this species were isolated from natural assemblages of benthic diatoms at different intertidal stations in the Westerschelde estuary (The Netherlands). At least two distinct semicryptic species of N. phyllepta were present, as shown by differences in the quantity of DNA per cell, the ITS1 sequences and the copy number of ITS per cell. DNA and chl a concentrations extracted from sediment surface samples were closely correlated, showing that the DNA used for subsequent analysis mostly belonged to the microalgal community. The results of real‐time qPCR from sites throughout the estuary and over several seasons agreed well with microscopic counts. Additionally, the seasonal pattern of the two forms of N. phyllepta showed an overlapping, but unique distribution along the estuary.     

On Branchiostoma californiense (Cephalochordata) from the Gulf of Nicoya estuary, Costa Rica

The cephalochordates are represented by the lancelets, of which species of the genus Branchiostoma are the best known. In recent years, these organisms have been the center of activity of studies focusing on the phylogenetic relationships of the chordates. In 1980, a survey of the benthos at 48 stations in the Gulf of Nicoya estuary, Pacific coast of Costa Rica, yielded 265 specimens of the lancelet Branchiostoma californiense. A total of 48 specimens was also collected at an intertidal flat in the mid upper estuary. Of the 48 subtidal stations, only eight had B. californiense, and these sites all had a sand fraction above 72%. The remaining stations ranged in their sand content from as low as 1% to as high as 92%, with an average of 25.9%, with 29 stations having a sand content lower than 72%. Lower salinities and muddy sediments may limit the distribution of the lancelet further upstream. This information is useful when changes over decades in the ecology of the estuary need to be evaluated against the background of local, regional, and global dynamics.     

Mercury pollution in the Ems estuary

From approximately 1960 to 1975 the Ems estuary received several tons of mercury per year from a chlor-alkali plant, a pesticide factory and some minor sources. The discharge has been reduced drastically from 1976 onwards. In 1975 and 1976 measurements were made on the distribution of mercury in the sediment. The horizontal distribution revealed a strong local enrichment of the sediment near the point of discharge. The vertical distribution was found to be in accordance with the local deposition rates. In the water phase no significant change in mercury content from 1975 to 1978/79 could be demonstrated. In 1978/79 a difference between Ems estuary and Dutch Wadden Sea was not significant. In 1978 mercury contents of eelpoutZoarces viviparus in the Ems estuary were about twice as high as in the Wadden Sea. In the Ems estuary a decrease of these contents was found between 1974/75 and 1978. A similar decline in the Wadden Sea may be related to a decreased mercury discharge by the River Rhine.     

九龙江口沉积物TCBS(Thiosulfate Citrate Bile Salts Sucrose)菌群的分布

【目的】调查九龙江流域对厦门海域潜在的病原菌"污染",为相关侵染性病害的预防和控制提供有价值的资料。【方法】通过TCBS(Thiosulfate Citrate Bile Salts Sucrose)培养基从九龙江河口沉积物中分离到158株细菌,应用16S rRNA基因-RFLP(限制性酶切图谱多样性分析)及16S rRNA基因序列分析等方法对158株细菌进行分子鉴定。【结果】研究结果表明九龙江口沉积物中分布的TCBS菌群分别属于7个属,其中假单胞菌属(Pseudomonas)占28%,气单胞菌属(Aeromonas)占24%,假交替单胞菌属(Pseudoalteromonas)占19%,希瓦氏菌属(Shewanella)占13%,芽孢杆菌属(Bacillus)占11%,弧菌属(Vibrio)占4%,嗜冷杆菌属(Psychrobacter)占1%。不同站位TCBS菌群的组成及各菌群的相对差异明显,其中上游区域以非嗜盐或耐盐细菌为主,下游区域以嗜盐细菌和耐盐细菌为主,具有典型的河口细菌分布特征。盐度对各TCBS菌群的分布具有重要的影响。弧菌在整个河口区所占的比例不大(6%-19%)且集中在下游区域。【结论】九龙江口存在大量的条件致病菌,其中以气单胞菌属为代表的耐盐菌,对厦门海域存在陆源性污染的风险;绝大多数弧菌属于海洋土著细菌,正常情况下(非流行性弧菌病期间)非来源于九龙江冲淡水的直接污染。     

Correlation of the distribution ofMesopodopsis slabberi (Crustacae,Mysidacea) with physico-chemical gradients in a partially-mixed estuary (Tamar,England)

The physical and chemical processes operating in the River Tamar Estuary (south-west England) have been comprehensively described and reported in the literature. There are well-established gradients of salinity, suspended sediment and oxygen which vary both on short-term (tidal) and long-term (seasonal) cycles. Freshwater runoff, the main factor determining salinity distribution, is also the cause of the high variability in suspended sediment concentrations. The biological processes are less well studied and information on the link between the benthic and pelagic systems is particularly lacking. Mysids, through their role as detritivores and as a major component in the diet of some fish, provide this link. Of the four species of mysid distributed longitudinally in the Tamar Estuary, the most abundant isMesopodopsis slabberi which occurs between 5 and 25 km from the estuary head. Observations over an annual cycle have shown marked seasonal changes in both abundance and distribution in the estuary. During winter and spring, densities remained generally low (<50 m⁻³) but, as water temperatures increased, the density increased and reachedca 1200 individuals m⁻³ in July. There was a shift in the longitudinal distribution ofM. slabberi in response to changes in the position of the salinity gradient. Adults comprised the majority of the population in salinities less than 10‰ whereas juveniles and immature animals were distributed over a wider area than the adults and occurred in water of higher salinity than the main adult distribution.M. slabberi appears to utilise the two-layered estuarine circulation to maintain its position in the estuary.     

春夏季闽江口和兴化湾虾类数量特征

本文利用2008年4月和9月闽江口和兴化湾海域渔业资源调查资料,研究这两个不同类型海域虾类密度的时空分布,优势种特征、地形地貌、海流和水文等因素对分布的影响。结果表明,4月闽江口虾类生物量(22.05kg/km₂)低于兴化湾生物量(23.33kg/km₂), 而尾数密度(12.34?10₃ ind./ km₂)高于兴化湾尾数密度(8.42?103 ind./ km₂),9月也是如此,闽江口虾类生物量(205.54kg/km₂)低于同期兴化湾生物量(329.60kg/km₂),但尾数密度(131.25?10₃ ind./ km₂)大于兴化湾尾数密度(95.79?10₃ ind./ km₂)。这一现象的产生,与闽江口和兴化湾虾类资源种类规格特征有一定的关系：依据优势性分析,在兴化湾,优势种以广盐性大规格的哈氏仿对虾为主,其它主要优势种优势性不明显,对总生物量变化的贡献不大。反观闽江口的优势种,除了广盐性的哈氏仿对虾,还有个体数量巨大的半咸水小规格中国毛虾,其中,中国毛虾尾数密度的百分比占了虾类的大部分。不同盐度环境,种类对不同盐度环境盐度适应是形成闽江口和兴化湾优势种不同格局的主要原因。在闽江口,南部渔场是当地的主要渔场,9月是主要的渔汛,与闽江径流量的季节变化和闽江口地形地貌特征有关。在兴化湾,湾口是虾类的主要产卵场和索饵场,湾外则是虾类越冬场,与构成资源主要种类哈氏仿对虾暖水性和兴化湾水团特征有关。不同季节比较,在9月,兴化湾和闽江口虾类资源品种呈现多样化的趋势,兴化湾和闽江口比较,闽江口虾类资源品种呈现更加多样化的特征。     

Ecology of the Ogun River estuary,Nigeria

The distribution of benthonic communities (particularly Foraminifera) were studied from fourteen samples obtained from the Ogun River estuary and environs. Ten species of benthonic Foraminifera were identified; two of these constitute over 90% of the total foraminiferal population.Two broad biofacies are recognisable, namely the upper estuarine facies of Ammobaculites and the lower estuarine facies comprising arenaceous and calcereous forms with a preponderance of Ammonia beccarii (Linnaeus).Large populations of few species occur in the lower estuary, an area of weakly saline water with marked salinity fluctuations. The upper estuary on the other hand is sparsely populated and contains tests mainly of arenaeous Foraminifera. A few species are distinctive of particular facies but some are distributed throughout the estuary. Substrate is not a causal ecological factor, because sediments are similar in physical attributes throughout the estuary. Salinity and rate of sedimentation are among the more important factors affecting the distribution of all species. The low-energy nature of the environment is established by the abundance of faecal pellets and the fragility of the tests of the arenaceous Foraminifera.     

The vertical and transverse distribution of larval herring in the River Blackwater estuary, Essex

The vertical and transverse distributions of spring-spawned larval herring were studied in the River Blackwater estuary, Essex. Sampling was undertaken during May when larval densities within the estuary were at a maximum for the year. At this time, larval lengths were in the range 7–16 mm. No clear diel pattern in the vertical distribution was found, although larval distribution at night was more even.
The tides were found to influence the vertical distribution. Surface waters (< 1.5 m in depth) were avoided during both flood and ebb tides, but used during slack water. Larval densities at ebb were higher near the sea bed than during the flood tide. It was concluded that this behaviour will tend to transport larvae into and retain them within the estuary.     

Modelling microbial processes (phyto- and bacterioplankton) in the Schelde estuary

Since about 10 years, studies have been conducted at the University of Brussels in modelling the microbiological processes affecting biogenic substances in the Schelde estuary and its watershed.The first model, a one dimensional redox model, simulated the longitudinal distribution of oxygen, nitrate, iron and manganese in relation to the observed bacterial heterotrophic activity. A model allowing calculation of bacterial activity from data on organic discharge was coupled to this model. It was completed by a model of phytoplanktonic development within the estuary. Finally, an idealized model of the hydrographical network, based on Horton analysis, is being established in order to calculate the quality of the water at the downward boundary of the estuary.Together, all these sub-models form a general model of the ecological working of the Schelde estuary, able to predict at least the general trends of the redox state, the organic carbon, mineral nitrogen, and chlorophyll-a concentrations as a function of distance to the sea, from the knowledge of geomorphological and meteorological data, along with informations concerning the distribution of anthropogenic discharges. This model therefore provides a powerfull tool for the rational management of the Schelde estuary.Research Associate of the Belgian National Scientific Research Funds.     

OBSERVATIONS ON THE NESTING SITES AND NESTING BEHAVIOUR OF THE KITTLITZ'S SANDPLOVER CHARADRIUS PECUARIUS

Jackson, S. 1984. Predation by Pied Kingfishers and Whitebreasted Cormorants on fish in the Kosi estuary system. Ostrich 55:113-132.

Identification of otoliths from the regurgitated pellets of Pied Kingfishers Ceryle rudis and Whitebreasted Cormorants Phalacrocorax carbo from the Kosi estuary system provides information on the relative proportions of fish species in the diets of the birds. This information can be related to the feeding habits, distribution and abundance of their prey. It is also an indication of the feeding range of the birds. There is little overlap between both the size classes and the species of fish taken by the two predators. This is because of the difference in size and fishing techniques of C. rudis and P. carbo, and of differences in their feeding ranges. Competition for food between the two populations of birds studied is minimized by these differences.     

The performance of the leaf mining microlepidopteran Bucculatrix maritima (Stt.) on the salt marsh halophyte,Aster tripolium (L.), exposed to different salinity conditions

Summary The performance of phytophagous insects is influenced by the nutritional quality of the food plant, which may vary with environmental conditions. Hardly any information exists on food-plant mediated effects of variable soil salinity on the performance of phytophagous insects. Conspicuous differences in salinity levels, however, are found in soils of intertidal wetlands such as salt marshes and mangroves. The growth of larvae of Bucculatrix maritima, a leaf miner of the salt marsh halophyte Aster tripolium, was studied on the host plant along the salinity gradient of the Westerschelde estuary (S.W. Netherlands). In addition, its performance on A. tripolium grown on low or high salinity culture medium was investigated experimentally. Although salinity conditions significantly influenced the chemistry of the host plants, insect performance seemed almost unaffected, although near the mouth of the estuary high environmental salinities may have caused some inhibition of larval growth. The results contrast with our previous studies on the stem-borer Agapanthia villosoviridescens, which showed that growth and development was conspicuously influenced by the changing characteristics of Aster tripolium along the estuarine salinity gradient. The location-dependent qualities of halophytes in an estuary thus appear to have species-specific effects on insect performance. We hypothesize that this phenomenon contributes to the existence of non-identical distribution patterns of phytophagous insects associated with the same halophyte in an estuary.     

Fish reproduction and the impact of acidification in the Kyrönjoki River estuary in the Baltic Sea

Synopsis Several freshwater species use the Kyrönjoki River estuary as a spawning and nursery area. The main reasons for this seem to be the morphology of the estuary, the abundance of shelter provided by aquatic macrophytes, high food production and favourable temperature conditions. Acidification of the estuary due to drainage from acidic soils has made part of the estuary unsuitable for fish reproduction. In addition, year to year fluctuations in the acidity of the estuarine water have affected the reproductive success of several species. The severity of the effects of the acidification at the population level is determined by the spatial and temporal distribution of the larvae and juveniles.     

Movement of adult Atlantic salmon in the Usk estuary, Wales

A total of 56 salmon was tagged in the Usk estuary using combined acoustic and radio tags. Those fish migrating within the estuary oscillated with the tide over c . 10 km, being towards the seaward end at low water and moving upstream on the flood tide. Fish migrating through the estuary moved upstream on the flood tide and stemmed displacement downstream during the ebb. These findings, together with information on the hydrodynamics of the estuary, indicate that the fish utilize tidal currents to migrate passively in their preferred direction.     

Variability of <Emphasis Type="Italic">Mya arenaria</Emphasis> growth along an environmental gradient in the Plum Island Sound estuary,Massachusetts, USA

An understanding of the environmental factors that determine how clam growth varies in space and time improves effective mariculture and shellfish management. We examined the importance of temperature, salinity and chlorophyll-a in controlling the spatial pattern of Mya arenaria growth, the commercially important soft-shell clam, in the Plum Island Sound estuary in northeastern Massachusetts, USA. We collected clams (>5.08 cm) monthly during the April to November growing season from which we determined growth rate, maximum size (L-infinity), and time to reach a harvestable size. We also surveyed selected sites along the estuary to estimate the relationship between clam size and weight. We collected environmental data along the estuary, and our data were complemented with data collected and maintained by the Plum Island ecosystems long-term ecological research project. Clams reached harvestable size fastest and had the greatest L-infinity at the most oceanic site (Yacht Club) in the estuary. Clams had the smallest L-infinity and were slowest to reach the harvestable size at the least oceanic site (Railroad Meander). The spatial patterns of clam growth were best explained by a positive distribution of salinity. Salinity significantly accounted for 95 % of the spatial variation of clam growth in the estuary. Snow melt in spring increases freshwater input to the estuary and results in the lowest spring salinity during a year, and this explained the upper estuary limit of clam distribution. IPCC-projected climate change will cause sea-level rise and increasing precipitation in the northeastern USA, which will modify the spatial pattern of salinity in the region’s estuaries. Our research therefore suggests that future management of M. arenaria, an important economic resource for the local economy, should be concerned with the changes of salinity distribution under climate and land-use change.     

The horizontal distribution of the benthic algal flora in the Patos Lagoon estuary, Brazil, in relation to salinity, substratum and wave exposure

Monthly collections of benthic algae were made during 1 yr at 11 stations between the mouth and the salt water limits of the Patos Lagoon estuary, Brazil. A total of 94 taxa of algae were recorded, including 40 Cyanophyta, 26 Chlorophyta, 1 Xanthophyta, 3 Phaeophyta, and 24 Rhodophyta. Although the number of Rhodophyta and Phaeophyta decreased towards lower salinities, due to local salinity patterns, species substitution among the Chlorophyta and increase of Cyanophyta in the estuary, the species number remained approximately the same between the mouth and the upper saline reaches of this estuary.

The distributional limits of 64 species in the flora resulted in the formation of three algal groups of negative correlation. The horizontal distribution of each group of species was related to type of substratum, wave exposure or salinity, or a combination of these factors. The individual evaluation of the factors demonstrated that, apart from salinity, substratum and degree of exposure are of primary importance for the horizontal distribution of a large part of the algal flora in this estuary.     

A simulation of the process of sedimentation of suspended solids in the Yoshii River estuary

A vertical plane 2D model has been applied to the Yoshii River estuary, Japan, as a means of simulating the process of sedimentation. The current velocity and isohaline distributions were well reproduced in the estuary and the model simulated the concentration distribution of suspended solids for 8 particle size classes by using a transport equation based only on physical processes. The changes of the particle size distribution in surface water were well reproduced by the model. The vertical velocity component plays an important role in the behaviour of suspended solids.     

On the use by birds of intertidal areas of the Tagus estuary: implications for management

The use of intertidal areas of the Tagus estuary by birds was re-analysed, based on data from 1990 to 1993, to describe (i) the temporal and spatial patterns of use of intertidal areas, (ii) the diet of birds during winter and (iii) the habitat selection patterns of feeding birds, during winter. The most common birds in the estuary were gulls, waders and ducks. Highest densities were recorded for most species in autumn and winter. The spatial distribution of birds in the intertidal areas of the estuary did not vary significantly across seasons, although broader distributions occurred when bird populations were present in high numbers. In autumn, use of intertidal areas was highly variable. Specific areas in the estuary were identified as holding important densities of birds, or having a high species richness. The most abundant species selected feeding areas according to sediment type, although the presence of channels, saltmarsh or humans also influenced the distribution of birds. The invertebrates Carcinus maenas, Hediste diversicolor and Scrobicularia plana were identified as key prey species. Plant material was important as food for ducks. Implications of these findings for the management of the estuary are discussed.