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1.
The numbers of six meiofauna groups (nematodes, copepods, turbellarians, archiannelids, oligochaetes and gastrotrichs) were estimated from 17 sandy beaches differing in their organic (sewage) pollution loadings. Nematodes were most abundant on polluted and fine sand beaches whilst copepods were more common on coarse sand and rare on polluted beaches. The ratio of nematodes to copepods may thus provide a useful index of beach quality. Archiannelids and oligochaetes seem restricted to particular habitat types and, with the turbellarians, have little potential for biomonitoring. Gastrotrichs occurred in large numbers on one polluted beach.  相似文献   

2.
The benthic faunal spectrum including bacteria, protozoans, meiofauna, wrack epifauna and macrofauna, was quantitatively surveyed on two modally reflective, moderate energy, Western Australian beaches. The more exposed beach had coarser sand, no intertidal macrofauna and a poor interstitial fauna. The less exposed beach had a large deposit of wrack totalling 161 kg m?1 dry mass concentrated on the lower shore. The amphipod Allorchestes compressa was abundant in the fresh wrack comprising most of the macrofauna. There were also fairly abundant small epifauna on the wrack. Dry biomass of macrofauna, epifauna, meiofauna, protozoans and bacteria was 0, 0, 15, 4 and 180 g m?1 on the more exposed beach and 160, 3, 112, 9 and 901 g m?1 on the less exposed beach with wrack. On the latter beach there was an inverse correlation between meiofaunal densities and the densities of protozoans and bacteria, suggesting grazing by the former on the latter. On both beaches meiofauna was concentrated in the mid- to upper beach, protozoans near the surface and bacteria in the mid- to lower beach. It is estimated that bacteria are responsible for most of the secondary production on both beaches.  相似文献   

3.
Meiofauna as descriptor of tourism-induced changes at sandy beaches   总被引：9，自引：0，他引：9  
Tourism has long been considered as a 'clean industry' with almost no negative effects on the environment. This study demonstrated, in two different coastal systems (Mediterranean and Baltic), that tourism related activities are particularly affecting the sandy beach meio- and nematofauna in the upper beach zone, the specific ecotone in which many meiofauna species from both the marine and the terrestrial environment congregate. Tourist upper beaches are characterized by a lower % total organic matter (%TOM), lower densities, lower diversities (absence of Insecta, Harpacticoida, Oligochaeta, terrestrial nematodes and marine Ironidae nematodes) and higher community stress compared to nearby non-tourist locations. The %TOM was found to be the single most important factor for the observed differences in meiofauna assemblage structure at tourist versus non-tourist beaches in both the Mediterranean and the Baltic region. The free-living nematode assemblages from tourist upper zones depart significantly from expectations based on random selections from the regional nematode species pool. Furthermore upper zone assemblages are characterised by a low species diversity consisting of taxonomically closely related nematode species with r-strategist features. Generally, faunal differences between tourist and non-tourist beaches are decreasing towards the lower beach zones.  相似文献   

4.
Effects of crude oil on the supralittoral meiofauna of a sandy beach   总被引：1，自引：0，他引：1  
The supralittoral zone of an open sandy beach was dosed with crude oil and changes in the meiofauna monitored. Treatments included weathered and fresh oil on the surface, fresh oil mixed with dispersant on the surface and weathered oil at the water table, all in layers 0·8 cm thick. In all cases the meiofauna was reduced 1 month after dosing but numbers had returned to normal by 5 months except in the site dosed with fresh oil mixed with dispersant. Oil on the surface had greater effects than oil at the water table; fresh oil had a greater effect than weathered oil and fresh oil with dispersant was more toxic than fresh oil alone. Nematodes were least sensitive to the oil and oligochaetes more sensitive, their numbers being correlated with oil concentrations and depth in the substrate. It is concluded that, under all but the heaviest conditions of pollution in their environment, recovery from oil contamination should occur within 5 months in the meiofauna.  相似文献   

5.
The effects of the disposal of copper mine tailings on the littoral meiofaunal assemblages of the Chañaral area of northern Chile were studied. Of the metals data collected, only in the case of copper was there a clear association with the tailings distribution in both the seawater and porewater samples, and it is assumed that the tailings on the beaches was the source of copper in the adjacent seawater. When compared to the reference sites, the meiofaunal assemblages at the impacted sites had significantly lower densities and taxa diversities; at the northern sites only the densities were lower. Otoplanid turbellarians were identified as characteristic of those beaches impacted by tailings. The combination of porewater copper and the amount of tailings present were identified as mostly responsible for the observed structure of the meiofaunal assemblages. It was also established that the variation in natural sediment grain size from beach to beach was not a significant factor in the observed differences in the meiofaunal assemblages. The two groups of meiofauna that proved to be most sensitive to the effects of tailings dumping were the foraminiferans and the harpacticoid copepods.  相似文献   

6.
We examined the effects of crude oil contamination on community assemblages of meiofauna and nematodes after exposure to total petroleum hydrocarbons in the laboratory. We administered a seawater solution that had been contaminated with total petroleum hydrocarbons to seven treatment groups at different concentrations, while the control group received uncontaminated filtered seawater. The average density of total meiofauna in the experimental microcosms diluted with 0.5%, 1%, 2%, and 4% contaminated seawater was higher than the density in the control. The average density of total meiofauna in the 8%, 15%, and 20% microcosms was lower than the density in the control. The density of nematodes was similar to that of the total meiofauna. Cluster analysis divided the microcosms into group 1 (control, 0.5%, 1%, 2%, and 4% microcosms) and group 2 (8%, 15%, and 20% microcosms). However, SIMPROF analysis showed no significant difference between the two groups (p > 0.05). Bolbolaimus spp. (37.1%) were dominant among the nematodes. Cluster analysis showed similar results for nematode and meiofaunal communities. The total meiofaunal density, nematode density, and number of Bolbolaimus spp. individuals were significantly negatively associated with the concentration of total petroleum hydrocarbons (Spearman correlation coefficients, p < 0.05). Within the nematodes, epistrate feeders (group 2A: 46%) were the most abundant trophic group. Among the treatment groups, the abundance of group 2A increased in low-concentration microcosms and decreased in high-concentration microcosms. Thus, our findings provide information on the effects of oil pollution on meiofauna in the intertidal zones of sandy beaches.  相似文献   

7.
Sea-level rise is likely to cause significant changes in the morphodynamic state of beaches in the higher latitudes, resulting in steeper beaches with larger particle sizes. These physical changes have implications for beach invertebrate communities, which are determined largely by sediment particle size, and hence for ecosystem function. Previous studies have explored the relationships between invertebrate communities and environmental variables such as particle size, beach slope and exposure to wave action, and often these physical variables can be integrated in various indices of morphodynamic state. Most of these studies incorporated a full range of beach types that included wave-dominated surf beaches, where the wave action is harsh enough to enable reliable estimates of breaker height, a parameter included in several of the indices, and concluded that more dissipative beaches with gentler slopes and finer particle sizes often support a higher number of species and greater abundance than more reflective beaches. Whether these predictions remain valid for less wave-dominated beaches, where breaker height is more difficult to determine, is uncertain. In the present study, the abundance of meio- and macrofauna was quantified across a range of beaches in the UK, which are generally towards the lower energy end of the morphodynamic gradient, and their relationships with beach physical properties explored. No significant relationships were found between abundance and the standard morphodynamic indices, but significant relationships were found for both macro- and meiofaunal abundance when these indices were combined with an exposure index (derived from velocity, direction, duration and the effective fetch). All the relationships identified between abundance and combined morphodynamic indices indicated a higher abundance of both macro- and meiofauna on the more dissipative beaches. The reverse was however found for species richness. If predictions that accelerated sea-level rise will move beaches towards a more reflective morphodynamic state are correct, this could lead to declines in the abundance of meio- and macrofauna, with potential adverse consequences for ecosystem functioning.  相似文献   

8.
A fortnightly sampling of tar balls on six beaches along the Israeli coastline between 14 April 1975 and 25 June 1976 showed that the mean content of tar during that period was 3625 g m?1 of beach front. The northern and central parts of the coast were significantly more polluted than the southern part. Between July 1975 and February 1976 the mean tar quantity decreased continuously from 5635 to 1344 g m?1.A comparison of tar quantities on the Israeli beaches with those of other beaches in the world showed that the Israeli beaches are more polluted than those of the west Atlantic coast, are as polluted as other beaches on the eastern coast of the Mediterranean Sea, and are less polluted than the beaches of Alexandria, Egypt, and Paphos, Cyprus. It is suggested that the tar content on the beach is related to the degree of oil pollution in the sea. The closer a beach is to an oil shipping lane or an oil dumping site, the heavier it is polluted.During storms, beach tar balls are pushed by the waves to the back of the beach or, in the case of a cliffed coast, are carried along the shore by the longshore current. When the tar balls reach a gap in the cliff (such as an estuary), they are carried inland by the storm waves. There the tar may become buried or dry, shrink and break into small particles which are then dispersed by the wind.  相似文献   

9.
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10.
Meiobenthic data from two microtidal sandy beaches of the eastern Mediterranean (Crete, Greece) were used to investigate patterns of both alpha and beta diversity in space and time. Copepod assemblages and environmental variables related to sediment characteristics, morphodynamics and food were studied over a year at four distinct habitats at each beach; the retention, resurgence and saturation zones of Salvat's intertidal scheme (midlittoral zone), and the surf zone of the sublittoral. Αlpha diversity analysis indicated similar species richness at both beaches when the whole 13-month data set was considered but was higher at the sheltered site when each sampling period was examined separately. Both beaches supported higher diversity in the sublittoral zone. Species richness increased seawards at the midlittoral zone of the sheltered site whereas, no pattern was evident at the exposed site, where the intense hydrodynamic conditions homogenized the sediments. Beta diversity increased markedly towards the sublittoral, indicating greater differences in alpha diversity between the sublittoral and the midlittoral zone. Species turnover was more variable at the exposed beach and at the most landward stations, where environmental conditions change often between extremes. A proportion of the variation in alpha diversity was explained by food availability at both beaches and additionally by grain size at the sheltered site. However, no environmental variable explained beta diversity patterns. Although the results of our study support the hypothesis of Multicausal Environmental Severity proposed for sandy beach macrofauna, we believe the classic Intermediate Disturbance Hypothesis is a more appropriate framework for the meiofauna communities of the studied sites.  相似文献   

11.
Sandy beaches, prime recreational assets that attract more people than other types of shorelines, are the main assets underpinning many coastal economies and developments. However, the intense stressors to the ecology of sandy beaches caused by recreational activities are generally underestimated or ignored. This study was the first to emphasize the ecological characteristics of recreational beaches in China and assess the response of macrobenthos at Liandao Beach, a typical sandy beach in the central part of China. Using the Before/During/After/Control/Impact (BDACI) method, differences in multiple variables (species richness, mean density, diversity) between a heavily recreationally impacted transect (TrH/Impact) and a less-impacted transect (TrL/Control) in different impact periods (Before, During & After) were applied to assess the response of sandy-beach macrobenthos to recreation and tourism. Meanwhile, a comparison between the macrobenthos conditions of the studied beach and reference conditions calculating from historical data of similar beaches with little recreation and tourism disturbances was carried out. Furthermore, the quality control chart approach was used to detect in detail the macrobenthos stable state and yearly response to recreational activities. The results showed that recreation and tourism posed a serious threat to the beach ecosystem; macrobenthos on the studied beach were seriously disturbed by recreational activities, and their variations were highly negatively related to the human recreational level. After monthly recreational impacts, the macrobenthos decreased sharply and recovered with difficulty during 1 year. Over the long-term, the macrobenthos had a sharp decreasing trend, which indicated that the ecological environment of the beach was highly disturbed. Conservation measures for recreational beaches are very challenging because of the economic value and popularity of sandy beaches as recreational sites. However, practicable conservation measures could be implemented that prevent or slow ecological degradation. A number of management and conservation suggestions are put forward, such as the establishment of the ecological carrying capacity of Liandao Beach in terms of direct recreational use, creation of themed exhibitions related to the beach macrobenthos and beach ecosystem and dissemination of this knowledge to visitors, implementation of spatial zoning of beach use, visitor management and environmental education.  相似文献   

12.
The macrobenthos of two exposed tropical sandy beaches in Rio de Janeiro (Brazil) were compared in relation to density, species richness, and vertical zonation. Biological and sediment samplings were carried out in the austral winter of 2002 and the austral summer of 2003. The sampling design consisted of 10 transects perpendicular to the water line, evenly divided into strata. A sampling unit was taken in each stratum with a 0.04 m2 quadrat sampler. Beaches were also compared according to physical features, such as slope, wave period, wave height, and grain size. According to Dean's Ω morphodynamic index the Pontal is a dissipative beach while the Costa Azul is a reflective one. The mean grain size ranged from median to coarse sand in Costa Azul, whereas in Pontal it ranged from median to very fine sand. Eleven species were collected in the two beaches. Crustaceans were the dominant in the Costa Azul Beach, while the polychaete Scolelepis squamata dominated the Pontal beach. A negative correlation was found between the density of the macrobenthos and mean grain size, and beach slope. On the other hand, the Dean's parameter correlated positively with faunal density. Based on the results of ANOSIM, in both beaches, two groups of stations were identified, defining an upper and a lower beach zone along the vertical distribution of the macrobenthos.  相似文献   

13.
海滩的稳定性及其演变是砂质海滩研究的重要内容。在全球砂质海滩普遍遭受侵蚀的背景下,分析部分稳定海滩的特征和原因可以为海滩维护和科学管理提供重要参考。本文基于近 11 年 （2010—2020 年） 青岛第一、第三和石老人海水浴场共 8 条典型剖面的实地监测高程数据,对海滩滩肩宽度和单宽体积进行计算对比,研究表明,除石老人海水浴场一个剖面变化较大外,其他剖面的滩肩宽度只变化了 0~14 m,是 11 年前的 0%~23.3%;单宽体积变化了 8.5~46.5 m3,是 11 年前的1.0%~9.4%;海滩剖面垂向扰动范围一般在 30~60 cm 范围内。海滩存在局部小尺度淤积或侵蚀,剖面形态总体较为稳定。海平面变化、台风和风暴潮等自然因素是海岸轻微侵蚀或调整的重要影响因素,但对海滩的优化管理 （包括定期监测海滩、适度展开养护、制定完善的管理政策和加强执行力度等人为因素） 可以应对这些海滩变化,并且已成为近年来该研究海滩保持稳定的关键因素。  相似文献   

14.
华南水东湾波控、中等潮差岬湾海滩地形动力分类   总被引：1，自引：0，他引：1  
海滩地形动力分类在国外的海岸地貌研究中已经被广泛接受。本文使用了华南粤西水东湾切线带、过渡带和遮蔽带海滩连续16个月32次大潮期间同步获取的波浪、潮汐、泥沙和海滩地形数据,分别按照无量纲沉降参数、相对潮差参数和无量纲海湾尺度参数对这一岬湾海滩不同岸段的海滩类型进行了研究,研究发现：（1）水东湾切线带海滩的主要状态为有裂流的低潮台地状态和沙坝型海滩状态,过渡带海滩主要状态是低潮沙坝/裂流海滩和沙坝消散型状态,遮蔽带海滩主要状态是有或无沙坝的消散型状态;（2）海湾不同岸段海滩状态的顺序变化与差异体现了岬湾海滩状态的时空变化性,与现场观测的海滩地形的变化基本一致,说明了对波控中到强潮海滩进行研究时,需要考虑潮汐的影响。同时,本文主要给出了海滩状态研究的一个框架体系,由于海滩不同的状态伴随不同的侵蚀模式,要求我国今后需加强在这一方面研究,以进一步丰富我国海滩地形演变、海滩地形动力过程和海滩防侵蚀的理论基础。  相似文献   

15.
This study describes the distribution patterns of interstitial polychaetes along morphodynamic gradients on six exposed sandy beaches in Santa Catarina and Paraná (South Brazil). Three random transects were sampled at two points on each beach, one at the swash and another at the surf zone, in winter and summer conditions. Six sediment replicates were collected at each sampling point using a corer of 4.6 cm internal diameter that removed 10 cm into the sediment. Abundance and composition of interstitial polychaete were correlated to wave height, slope, grain size, CaCO3, chlorophyll a , omega indexes, temperature and relative tide range using a canonical correspondence analysis (CCA). A factorial ANOVA showed that taxa richness, mean density and Shannon's diversity were significantly higher at the reflective beaches, but average values differ significantly between transects and these differences change according to the beach zones on both sampling dates. PERMANOVA showed that polychaete associations differ among transects according to the beach zones. The composition of interstitial polychaete associations was significantly correlated to beach morphodynamics and features (P < 0.01). Polychaete associations of reflective beaches were more diverse than in other morphodynamic states. Intermediate beaches may also sustain diverse associations due to temporal variability of the morphodynamic patterns. Beaches presenting extreme dissipative morphodynamics and compacted sediments appear to be unfavourable for the occurrence of interstitial polychaetes.  相似文献   

16.
The structure of macrofaunal communities at two similar exposed sandy beaches on the western coast of Portugal was monitored for approximately 18 months by sampling all the beach area, from the shoreline to the base of the dunes. The beaches’ physical environment, as well as community density and composition, seasonal variations and the potential relationships between biological data and environmental parameters were studied. The two beaches had similar exposure to wave action, but differed in terms of sediment grain size, extent of the intertidal area, sediment moisture content and, especially, in the potential food availability in the form of allochthonous debris. Differences were observed with regard to the communities’ structure, namely regarding composition and relative contribution of the dominant species. Seasonality, especially temperature variations, and the interaction between seasons and the beach zones (supralittoral vs. intertidal) also had a strong influence on communities: controlling dominant species’ density and the horizontal distribution of the dominant species, and promoting a differential utilization of the beach by several resident macrofaunal animals. The present study allows the identification of key species in exposed sandy beaches of western Portugal and demonstrates that a steady community structure does not persist in the similarly exposed conditions observed, which may be mainly a response to distinct detritus subsidies, combined with differences in sediment grain size, sediment moisture content and extent of the intertidal area.  相似文献   

17.
在波浪和水流的作用下,泥沙在不同时间尺度下的运动会引起沙滩的冲淤演变,对海岸资源有重要的影响。因此,了解沙滩季节性演变规律,并采取针对性的防护措施,是近岸沙滩亟须解决的问题。目前,现场观测是研究沙滩剖面冲淤演变的重要方法,通过沉积物组成、岸滩坡度及波浪动力的时空变化,了解沙滩剖面的变化特性,对于沙滩管理和海岸保护具有十分重要的意义。基于2017年9月—2019年11月在荣成楮岛南岸沙滩每个月采集一次的剖面数据,以及波浪动力数据,分别探究了沙滩在不同时间尺度下的变化特征,并对沙滩变化特征与波浪动力因素的相关性进行了探讨。研究发现：楮岛南岸沙滩形态变化具有较强的季节性特征,春季沙滩比较稳定;夏季沙滩受台风影响侵蚀严重,但在风暴过后的短时间内,沙滩泥沙恢复较快;冬季沙滩恢复速度逐渐减缓并趋于稳定。在夏季和冬季期间,波能流密度的向岸分量对楮岛南沙滩的演变产生重要作用,而且波能流密度向岸分量的均值（选取数据采集前15 d的波浪条件参与计算）与沙滩体积的相关性最好,并给出了两者的线性拟合公式。  相似文献   

18.
The applicability of recommendations of the Eurosion project to define a policy to manage coastal erosion has been tested at the “beach” scale in the Mediterranean coast. Thus, a favourable sediment status has been defined for these beaches taking into account their main functions: recreation and protection. Because they act at two different seasons, this status needs to be seasonally defined. For the protection function, the favourable sediment status depends on the level of safety fixed by the manager taking into account the importance of existing infrastructures and, for recreation it depends on the use density of the beach. The concept has been formalized for beach management within a framework where benchmarking plays a crucial role to determine the need of intervention. This has been illustrated for open cell beaches where one of its boundaries can permit variations in the sediment budget and for pocket beaches that act as closed sediment cells.  相似文献   

19.
This article offers some reflections on beach management, on the basis of the results of a survey on the recreational use of beaches and beach users' perception, which was carried out in the Metropolitan Region of Barcelona in 1992. The first part outlines the situation of the beaches, recent metropolitan beach policy and the organization of administrative bodies responsible for beach management. Survey objectives and methods are also explained briefly. In the second part, the principal results of the survey are presented and different beaches are compared in an attempt to analyse the types of users, the uses they make and the perception they have of the beaches. The conclusions identify new emerging social needs which demonstrate that new trends in beach management are also needed. Practical recommendations, related to this emerging perception of beaches as natural systems, are suggested.  相似文献   

20.
The species composition, densities, biomass and zonation patterns of the macrobenthos of sandy beaches are greatly influenced by the morphodynamics and morphology of the beaches. Macrobenthic zonation patterns along a small-scale morphodynamic gradient, comprising eight Belgian beach sites, were investigated. By taking into account the dimensionless fall velocity (Ω) and the relative tidal range, the beach sites were ordered along the gradient from the ultra-dissipative beach type (UD) to the low tide bar/rip beach type (LTBR). The resulting beach state index varied between 1.8 and 4.2 and the beach profiles were related with the beaches' morphodynamic state.In total 35 macrobenthic species, mainly polychaetes and crustaceans, were encountered, varying between 19 and 23 species per beach site. The species composition was quite similar among beach sites, with Scolelepis squamata being abundant at all eight sites. Furthermore, the macrobenthic distribution patterns were mainly related to elevation at all beach sites. Some remarkable difference in metrics, largely related to the beach morphodynamics and the consequent hydrodynamics, were found. At the hydrodynamically benign and consequently macrobenthos-rich UD beaches, the highest macrobenthic densities and biomass occurred on the upper beach, while at the hydrodynamically harsh and thus macrobenthos-poor LTBR beaches, the maximum densities and biomass occurred lower on the beach. Species, typically occurring on the upper UD beaches, such as Eurydice pulchra, S. squamata, and Bathyporeia sarsi, were restricted to the sub-optimal middle and lower beach zone at LTBR beaches. Only Bathyporeia pilosa was found on the upper beach of both UD and LTBR beaches. The more robust polychaete Ophelia rathkei and the interstitial polychaete Hesionides arenaria were exclusively found in the hydrodynamically harsh conditions of the middle LTBR beach zone.  相似文献   

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