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1.
Michele V. Blackburn Fiona Hannah Andrew Rogerson 《Estuarine, Coastal and Shelf Science》2009,84(4):519-526
During the period January to December 2004, monthly intertidal sand samples were collected from John U. Lloyd State Park beach, Florida. This study is the first to report on spatial and temporal distributions of heterotrophic (apochlorotic) diatoms in a sub-tropical beach, or indeed any sandy beach. Two non-pigmented, apochlorotic diatom morphotypes (strains III and IV) were consistently isolated from two intertidal beach sites and neither conformed to the morphologies of described species. Apochlorotic diatoms were found throughout the year and formed significant peaks in April, attaining total diatom counts of 71.1 and 94.9 cells g−1 wet sand, for the upper tidal zone and lower tidal zone, respectively. Valve morphology is described in detail for the two diatom morphotypes isolated from the beach sites (strains III and IV). Growth responses to changes in salinity (reflecting those of the intertidal zone) were examined in the laboratory for these diatoms. Both morphotypes were euryhaline, tolerating salinities between 10 and 50, and maximum growth rates were achieved at salinities between 20 and 40. Diatoms grew equally well whether grown in the light or the dark and showed no evidence of pigments when viewed by epifluorescence microscopy. The ability of diatoms to burrow into agar and carrageenan at different concentrations was tested. Both morphotypes were observed to develop burrows through non-nutrient agar up to twice the standard concentration (30 g agar l−1). The ease with which these heterotrophic diatoms formed burrows suggests that they were digesting these complex carbohydrates (i.e. phycocolloids) as a nutrient source. Strain IV, however, failed to burrow in a different phycocolloid, carrageenan. Similar degradative actions in the field might have implications for the breakdown of recalcitrant materials or allow diatoms to effectively compete with bacteria for carbon and nutrients. 相似文献
2.
荣成月湖潮间带单细胞趋磁细菌的多样性研究 总被引：1，自引：0，他引：1
Marine magnetotactic bacteria were collected from the intertidal sediments of Yuehu Lake(China), where their abundance reached 103–104 ind./cm3. Diverse morphotypes of magnetotactic bacteria were observed, including cocci and oval, vibrio-, spirillum-, rod-, elliptical-, handle- and bar-shaped forms. The magnetococci were the most abundant, and had flagella arranged in parallel within a bundle. The majority of magnetosomes were arranged in one, two or multiple chains, although irregular arrangements were also evident. All the results of high-resolution transmission electron microscopy(HRTEM) analysis show that magnetosome crystals were composed of Fe3O4, and their morphology was specific to particular cell morphotypes. By the 16 S r RNA gene sequence analysis, we found fourteen operational taxonomic units(OTUs) which were related to magnetotactic bacteria. Among these, thirteen belonged to the Alphaproteobacteria and one to the Gammaproteobacteria.Compared with known axenic and uncultured marine magnetotactic bacteria, the 16 S r RNA gene sequences of most magnetotactic bacteria collected from the Yuehu Lake exhibited sequence identities ranging from 90.1% to96.2%(97%). The results indicate that microbial communities containing previously unidentified magnetotactic bacteria occur in the Yuehu Lake. 相似文献
3.
为了解红树林不同潮位沉积物中底栖真核生物群落分布,基于18S rRNA基因采用高通量测序方法分析了广西北仑河口陆缘、林中和海缘3个潮位红树林沉积物中底栖生物群落结构。结果表明,北仑河口潮间带红树林沉积物中底栖生物多样性丰富,Shannon-Wiener指数变化范围在6. 08～6. 73之间; PCA分析表明潮间带中底栖生物群落差异较大,陆缘红树林中扁形动物、节肢动物和软体动物相对丰度较高,林中区域中纤毛虫、环节动物和轮虫相对丰度较高,海缘红树林中硅藻相对丰度较高;红树林中主要OTUs有桡足类的太平洋纺锤水蚤(Acartia pacifica)、硅藻类的海链藻(Thalassiosira sp.)、纤毛虫类的前管虫(Prorodon teres)、多毛类的小头虫(Capitella sp.)。高通量测序方法能较全面反映红树林区微型/小型底栖生物群落,研究结果为丰富红树林底栖生物群落研究和解析底栖生物在红树林生态系统发挥的作用提供基础数据。 相似文献
4.
《Oceanologica Acta》2003,26(5-6):457-471
Merja Zerga lagoon, located on the Moroccan Atlantic coast, is a site of international value (Ramsar Site) in terms of its ornithological diversity. However, the lagoon is heavily exploited for its clams and fishes. In an effort to further understanding of lagoon ecosystems, and thus to facilitate the management and conservation of their resources, an ecological survey of its benthic component was carried out. Benthos is a valuable food source for birds, fishes and humans. This work involved identifying the macrozoobenthic communities in the lagoon and assessing their spatial distribution. The study was based on monthly sampling of the intertidal zone and seasonal sampling in subtidal zone, over a one-year period. In the intertidal zone, salinity and median diameter and silt content of the sediment exhibited a gradient extending from the entrance to the inner lagoon, according to tidal flow. Sediment grain size characteristics reflected a gradual decrease of tidal currents from the lagoon entrance towards the inner parts of the lagoon, i.e. silt content increased with distance from the entrance. In the subtidal zone, the tidal currents were fairly strong throughout the lagoon, leading to the presence of coarser sediments than in the intertidal zone. Based on these physical, chemical and substratum characteristics, three communities were identified: (i) Cerastoderma edule and (ii) Scrobicularia plana communities were located in both the intertidal and subtidal zones; and (iii) a Tapes decussata community that was only found in the subtidal zone. The assemblages in the subtidal zone were more diverse and the mean abundances of the constituent species were higher than in the intertidal zone, which is an interesting feature for a lagoon environment. Communities were distributed along an ecological gradient, without showing a discontinuity or ecotone. The lagoon functioned like an estuary in which the community structure was controlled by edaphic factors in the intertidal zone, and by the hydrological factors in the subtidal zone. 相似文献
5.
三都湾互花米草的遥感监测 总被引：8，自引：0，他引：8
本文尝试通过分析滩涂上外来入侵植物群落的植物学和生态学特征,就闽东宁德地区三都湾海域的互花米草生长与变化状况,探讨如何实现利用遥感数据快速监测滩涂上的外来入侵植物的方法,为生物入侵监控工作提供决策依据.研究表明以缨帽变换的方法处理LandsatETM 和TM多光谱数据所获得的土壤视面和植被视面为基础,进行分层次分类可监测滩涂上互花米草的生长与分布扩展状况. 相似文献
6.
We developed a new methodology to determine CO2 fluxes in intertidal and shallow subtidal plant communities, namely seagrasses, both when the plants are submerged and when they are air-exposed. The apparatus comprises closed incubation chambers and a gas exchange column, designed to remove carbon dioxide from the water. Different types of incubation chambers were designed and built to adapt the system to distinct environments and incubation requirements. The methodology was tested under a comprehensive range of situations and its advantages and limitations are discussed. Overall, the method provides precise measurements of community carbon dioxide fluxes, through a fast and non-intrusive process, allowing repeatable in situ measurements of carbon uptake both in submerged and air-exposed conditions. As the experimental apparatus is identical, directly comparable measurements of air-exposed and submerged community production may be obtained, allowing sound estimates of daily carbon budgets of intertidal and shallow subtidal communities. 相似文献
7.
Studies on island intertidal benthic ecology in Fujian 总被引：1，自引：0，他引：1
lNreomicrlowIntertidal zone is an important type of wetIand easystem on the earth as it is in the tranai-tion zone between 1and and the and subject to frequent human interferences. Since the inter-tidal sone is subject to a1ternative physical and chemical actions of land and as, the intertidalzone has a compticated and changeable environment. The studies on intertidal zon ecobeyhave always attracted much attention for the past decades (Stephensons, l972; MOrtons,l983: Huang and Zhu, l998; Y… 相似文献
8.
A rich and diverse bottom ciliate fauna (168 species) was observed in the course of the studies of the subtidal and intertidal zones of the Pechora Sea; 81 of them were encountered for the first time in the Barents Sea region. As compared to the intertidal fauna, the sublittoral ciliofauna featured a higher species diversity but a lower total abundance (32.6 and 20.7 species per station and 10–100 and 2.4–443 ind./cm2 in the subtidal and intertidal zones, respectively). With respect to trophic strategies, raptorial feeders were most abundant in the sublittoral zone (up to 77% of the total biomass), while both raptorial feeders (45%) and upstream filter feeders (36%) dominated in the littoral sediments. In the subtidal zone, two different types of ciliate communities were distinguished according to their total abundance and species composition. The first type is represented by abundant and species-rich communities mainly dominated by large specific interstitial ciliates developed over fine-grained well-sorted sands. The second type of communities joins mainly nonspecific eurybiotic ciliates dwelling over heterogeneous silty sediments; they feature lower abundance and species richness values. The high species diversity, the low abundance or absolute absence of meso-and polysaprobic groups indicating organic pollution, and the high values of the ABC size structure index suggested a good condition of the sediments and biota in the region studied. 相似文献
9.
Laure M.-L.J. Noël John N. Griffin Richard C. Thompson Stephen J. Hawkins Michael T. Burrows Tasman P. Crowe Stuart R. Jenkins 《Estuarine, Coastal and Shelf Science》2010
An open incubation method has been used in many studies to directly estimate primary productivity and ecosystem functioning by measuring photosynthetic and respiratory rates in intertidal rockpool communities. The method measures changes in dissolved oxygen concentrations recorded in situ during an artificial dark period (respiration) and a natural light period (net primary productivity). Although this method has yielded interesting results, its advantages and limitations have yet to be thoroughly tested. The accuracy of the method was investigated in a controlled laboratory environment and compared with field incubations. Atmospheric oxygen diffusion across the air–water interface did not affect incubation measurements under low wind speed (<2 m s−1). Temperature increases during incubations were not greater than in natural rockpools and did not affect primary productivity. The major problem was the oxygen supersaturation which inhibited photosynthesis, thus leading to an underestimation of primary production. To allow comparable measurements, net primary productivity needs to be recorded during the linear phase of the photosynthetic process (<30 min of light) before water reaches supersaturation (<160%). This method gives rapid and reliable estimates of primary productivity thereby allowing biodiversity and ecosystem functioning relationships to be tested using rockpools as natural mesocosms. 相似文献
10.
The macrobenthos is important in benthic remineralization processes; it represents a trophic link and is also often used as a bio-indicator in monitoring programs. Variations of the environmental parameters strongly influence the structure of the macrobenthic communities in the marshes and since macrobenthos is the most important food item for marsh-visiting fish species in the Schelde, the variation in food resources can have a strong effect on the higher trophic level. The present study deals with the variation in macrobenthic communities in different habitats of intertidal marshes along the salinity gradient and the differences between the marsh creeks and the intertidal part of the estuary. The study measured density and species richness together with the biomass, and sampled a large intertidal channel and a smaller creek within five marshes along the salinity gradient of the Schelde estuary every six weeks between May and October in 2000. 相似文献
11.
The Water Framework and Habitats Directives require the evaluation of both the conservation and ecological status of macroalgae communities at water body or habitat level. However, assessments of macroalgal communities are highly time-consuming, both in terms of sampling effort and laboratory processing. These constraints have brought about their oversight in many marine monitoring programs, especially in subtidal environments. By using data from intertidal and subtidal macroalgae assemblages of Mouro Island (North coast of Spain) we wanted to identify possible cost-effective methods for monitoring this biological indicator, based on both high taxa levels and use of representative taxa. Multivariate analyses were applied using different data transformations. The results show that macroalgal communities are robust to aggregation to genus or even family level. Moreover, the outcomes show that transformation types introduce higher variation in the multivariate pattern of samples than the taxonomic level to which organisms are identified. Also, the study supports the use of representative taxa as a surrogate to overall community structure. Therefore, we conclude that a rapid-assessment by means of field evaluations, based on coverage of representative taxa, is a reliable alternative for the assessment of macroalgae status. In addition this procedure allows evaluation at a broader spatial scale (water body or habitat level) than traditional quantitative sampling procedure does. 相似文献
12.
本文应用数理统计的方法研究了象山港、三门湾软底相潮间带中７个断面的底栖动物群落结构。根据断面的位置及其群落的变化特点，可以比较明显地分为开敞性程度高的湾口群落和屏蔽性程度高的湾底群落。湾口群落不稳定、群落结构季节变化较大，湾底群落则相反，并且形成代表群落的特征种。从湾底到湾口，群落的Ｓｈａｎｎｏｎ－Ｗｉｅｎｅｒ多样性指数Ｈ＇（Ｓ）和Ｐｉｅｌｏｕ均匀度Ｊ均增加，而Ｍａｒｇａｌｅｆ种类丰度ｄ和ＭｃＮａｕｈｏｎ优势度Ｄ均减少。对环境诸因子的聚类分析结果基本上与相似性群落数量的聚类分析结果相同，表明群落的形成与环境因子的影响有一定的关系。 相似文献
13.
Anne‐Maree Schwarz 《新西兰海洋与淡水研究杂志》2013,47(5):809-818
Photosynthetic characteristics of intertidal Zostera capricorni were measured under different tidal conditions in Whangapoua Harbour on the eastern Coromandel Peninsula, New Zealand, and compared with permanently submerged seagrass beds. Photosynthetic characteristics were measured using pulse amplitude modulated (PAM) fluorom‐etry and oxygen (O2) electrode techniques. Gross light saturated photosynthesis measured as oxygen exchange averaged 5.74 and 5.36 mg O2 g–1 dry weight (DW) h–1 and leaf respiration rates averaged 1.22 and 1.38 mg O2 g–1 DW h–1, for intertidal and subtidal plants respectively. Photosynthesis of both intertidal and shallow subtidal plants was light saturated at between 195 and 242 μmol photons m –2 s–1, suggestive of acclimation to a high light environment. Despite the period of exposure at low tide clearly being an important time for photosynthetic gains for intertidal plants, when water clarity was sufficiently high, maximum rates of photosynthesis were also possible when the beds were submerged. If average water clarity was at the clearer end of a range measured for this site (Kd = 0.85 m–1) then it was calculated that for intertidal seagrass beds growing at mean sea level in Whangapoua, c. 50% of above‐ground production could occur while plants were submerged. 相似文献
14.
对海南岛海岸澄迈角沙滩的3个断面进行了潮间带生态调查。初步鉴定无脊椎动物32种,其中软体动物8种,甲壳类14种,多毛类8种,其它动物2种。优势的大型底栖动物有端足类的肢突跳钩虾Talorchestia brito,等足类的日本异浪漂水虱Excirolana japonica和双壳类的等边浅蛤Gomphina aequilatera。垂直分布可分为:(1)钩虾带,以肢突跳钩虾为特征种;(2)等足类带,以日本异浪漂水虱为特征种;(3)蛤-螺带,以等边浅蛤-(虫昌)螺Umbonium vestiarium为特征种。研究表明,沙滩底栖动物垂直分布主要受潮汐、底质、盐度和波浪的影响。 相似文献
15.
When Hurricane Iniki struck the Hawaiian Islands in September 1992, it provided a rare opportunity to examine the immediate effects of a hurricane on two intertidal benthic communities off the reefs of O'ahu, Hawai'i. The Niu Beach site contained large, obvious aggregations of the tube building polychaete Diopatra dexiognatha, and the Wailupe Beach site was without obvious tubiculous fauna at the surface. Ten replicate sediment cores were taken before and after the hurricane with a 7.6 cm PVC corer and organisms were identified to family and enumerated. There were no substantial depletions or loss of taxa after the hurricane. Oligochaetes were the most dominant taxa pre-and post-hurricane. The abundance of all dominant polychaete families increased post-hurricane. The three most abundant polychaetes were capitellids and D. dexiognatha (Onuphidae) at Niu Beach and Pygospio muscularis (Spionidae) at Wailupe Beach. We suggest that D. dexiognatha and P. muscularis help stabilize the sediments since they both form dense tube mats while capitellids and oligochaetes are considered highly adaptive surface burrowers that can take advantage of newly disturbed sediments. Overall, there was no substantial effect observed on the intertidal fauna exposed to this severe disturbance. It is suggested here that invertebrate communities in this area are adapted to survive and thrive in high-energy environments and possibly benefit from dense aggregations of tube building polychaetes. 相似文献
16.
In the weeks following the 2011 Rena oil spill, a series of surveys was initiated on eight rocky intertidal reefs to describe the distribution of oil and to assess the impacts of oil on ecological communities. Consistent but relatively low cover of oil occurred at two sites (Mt Maunganui and Moturiki). The area covered by oil had decreased by c. 90% after 5 months due to natural weathering processes. There were immediate effects of oil fouling on the mussel Limnoperna pulex and its associated fauna, with reductions in the number of mussels and infaunal taxonomic richness. However, no ecological effects on any of the communities were detectable after 1 month. Overall, the ecological effects of the Rena oil spill on rocky shore intertidal communities were small and not long-lasting, but we stress that this does not consider potential sublethal effects and their consequences on organisms. 相似文献
17.
Samantha B. Joye Mandy L. Mazzotta James T. Hollibaugh 《Estuarine, Coastal and Shelf Science》1996,43(6):747-766
Community metabolism and nutrient, iron (Fe) and manganese (Mn) cycling were examined in two intertidal, marine, microbial mat communities during short (4–5 days) incubations in closed, flow-through microcosms. Sediment microcosms were incubated under either light (light–dark cycles) or dark (continuous darkness) conditions to assess the effect(s) of photosynthetic oxygen production and microalgal activity on nutrient, Fe and Mn cycling. The effects of chemical redox reactions between reduced sulphur (S), Fe and Mn cycling were examined by blocking sulphate reduction, and reduced S production, with 25 mM molybdate while incubating under dark conditions.In light-incubated microcosms, negligible fluxes of nutrients (nitrogen and phosphorus) and trace metals were observed. A substantial sediment–water flux of reduced Fe (Fe2+) and Mn (Mn2+) was observed in microcosms incubated under continuous darkness; highest fluxes were observed in molybdate-amended microcosms. At both sites, biologically-mediated redox reactions accounted for a substantial (>50%) portion of the Fe2+and Mn2+flux. Both microbial mat communities exhibited similar rates of gross photosynthetic oxygen (O2) production, but dramatically different rates of net benthic O2flux. Distinct patterns of net O2production and trace metal cycling arose from differences in either trace metal oxide availability or reactivity (mineralogy), organic carbon mineralization rates, or sediment characteristics (porosity). Variations in the microbial community responsible for trace metal cycling could have also contributed to the pattern. The present data illustrate that chemically-mediated redox reactions between metal oxides and reduced S complicate interpretation of Fe and Mn fluxes, underscoring the need to separate chemical and biological reactions when attempting to determine the role of biological trace metal reduction in organic carbon oxidation. 相似文献
18.
青岛潮间带大型底栖海藻群落的研究 总被引：3，自引：0，他引：3
在青岛潮间带布设了显浪咀、太平角和石老人3个断面,进行了为期1 a(2006年8月～2007年11月)的大型底栖海藻资源调查研究.结果表明:1. 青岛潮间带大型底栖海藻群落的种类组成中红藻种类最多,其次是褐藻,绿藻最少.2. 群落中大型底栖海藻的生物量有明显的季节变化:春季>夏季>秋季>冬季;生物量在垂直分布上表现出中、低潮带均大于高潮带;在水平分布上无明显差异.3. 底栖藻类群落优势种无季节性变化,第一优势种为孔石莼.4. 采集到大型底栖海藻43种,其中红藻门22属24种,占55.8%;褐藻门9属11种,占25.6%;绿藻门6属8种,占18.6%. 相似文献
19.
滨海湿地互花米草的生态经济影响分析与风险评估探讨 总被引：6，自引：0，他引：6
在文献分析和调查研究的基础上，系统分析了滨海湿地互花米草的生态经济影响，如滩涂淤积、土壤理化性状变化，养殖埕地消失，土著植物退化或基因丧失，底栖生物多样性指数减小，涉禽种群结构数量改变，滩涂经济效益下降；并就互花米草建立了风险评估指标体系；总结指出，应对互花米草的入侵和蔓延采取必要的控制措施． 相似文献
20.
Sílvia C. Gonalves Pedro M. Anastcio Miguel A. Pardal Patrícia G.Cardoso Susana M. Ferreira Joo C. Marques 《Estuarine, Coastal and Shelf Science》2009,81(4):555-568
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