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麻痹性贝类毒素(paralytic shellfish toxins,PSTs)是由某些甲藻产生的一种高毒性神经毒素,在海洋环境中分布广、危害大,可对水产养殖和人类健康造成重大危害;PSTs毒素的毒性大小随种类和结构的不同有较大差异。迄今,国内外学者针对PSTs的来源分布、迁移转化、生物合成及其影响因素等开展了大量的调查研究,但目前对于藻细胞产毒的生物合成途径、遗传学特征及其环境调控机理等研究仍处于起步阶段。PSTs的生物合成过程不仅与藻细胞自身生长阶段有关,还会受到光照、温度、营养盐等多种环境因素的影响,环境条件的改变会引起藻细胞毒素组成和含量发生不同程度的变化。近年来,研究人员应用基因组学和蛋白质组学技术,发现了产生PSTs的典型甲藻——亚历山大藻(Alexandrium)细胞内与PSTs毒素生物合成相关的某些基因或蛋白质,对我们更清晰地了解亚历山大藻产生PSTs毒素的机制具有重要意义。本文综合以往的研究报道,对亚历山大藻中PSTs的生物合成与转化及其主要影响因素进行了总结,以期为产毒有害藻华的防治提供科学依据。 相似文献
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Anthropogenic factors and habitat complexity influence biodiversity but wave exposure drives species turnover of a subtropical rocky inter‐tidal metacommunity 
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下载免费PDF全文 Coastal ecosystems are complex and species rich, but are vulnerable to degradation from a variety of anthropogenic activities. Nevertheless, information on inter‐tidal community composition in the Caribbean Basin and at other oceanic sites is lacking. Such information is essential to developing a more comprehensive understanding of rocky inter‐tidal systems and their responses to global change. The goals of this study were to determine the relative importance of environmental (wave power density, wave height), habitat (e.g. algal cover, slope, complexity of rock surfaces) and anthropogenic (distance to roads, population density) factors associated with the structure of local assemblages at multiple shore heights and the regional metacommunity of mobile invertebrates on oceanic rocky inter‐tidal habitats. Environmental characteristics associated with habitat complexity (algal cover, rock surface complexity) and human population density were most strongly associated with abundance and biodiversity of invertebrates. Species richness was positively correlated with surface complexity, but abundance was negatively correlated with both surface complexity and per cent algal cover. By contrast, abundance of invertebrates was positively correlated with human population density, and diversity was negatively correlated with human population density. Abundance of invertebrates was greatest in the mid inter‐tidal zone, whereas diversity was greatest in the lower inter‐tidal zone. Metacommunity structure was Gleasonian, but the gradient along which species turnover occurred was correlated with measures of wave exposure, rather than anthropogenic activity. Unlike in previous studies, mostly at mainland sites, human activity primarily altered dominance patterns of communities, while having relatively little effect on species richness or composition. 相似文献
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Spatial and temporal variation of diverse inter‐tidal algal assemblages in Southwest O‘ahu 下载免费PDF全文
下载免费PDF全文 Spatial and temporal variation in tropical inter‐tidal communities is poorly known, making predictions about the effects of climate change and other anthropogenic disturbances difficult. Along Southwest O‘ahu, Hawai'i, local residents are concerned about the environmental effects of coastal development and the perceived loss of targeted algal species, which are collected for human consumption. To describe the coastal benthic community and better understand the processes that form and maintain it, the abundance and composition of macroalgae were sampled in the region's inter‐tidal zone from 2006 to 2015. Sixty‐six macroalgal species and two broad algal assemblages were identified that corresponded to substrate topography and sand influence at a similar tidal elevation. Along flat carbonate benches with a sand beach, Phaeophyceae and Rhodophytes occurred in almost equal proportions, while shores with slightly more topographic relief and angular substrate were dominated by Rhodophytes. Foliose or turf algal forms were most common. Surveys captured the local invasion of an alga, Avrainvillea sp. and significant declines in abundant macroalgae in 2015 after a period of unseasonably warm, calm water. Temporal changes in algal assemblages were related to maximum water temperature and wave height but not precipitation. Thus, algal assemblages appear to be structured by local beach morphology as they interact with sand and wave activity and episodically by unusual weather events. However, manipulation and continuous monitoring of the algal assemblages coupled to sensing of the localized environment is necessary to confirm factors related to assembly maintenance and recent species shifts. 相似文献
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海洋发光甲藻是指海洋中在受到物理扰动刺激时可以发出可见光的一类甲藻,是海洋中非常重要的发光生物类群,也是海洋浮游植物中唯一具有发光能力的类群。近些年,由于其独特的发光功能,发光甲藻被人类应用到很多方面,比如环境污染物的毒性检测、海洋浮游植物的生物量监测和有害藻华的预警,以及海洋军事中的追踪和探潜等。国外关于海洋发光甲藻的研究起步较早,目前在分类、生态乃至生理和生化方面都取得了一定的进展。国内该方面的研究起步较晚且较少,相关的基础和应用性研究亟需开展。本文针对当前国内、外关于发光甲藻的研究进行综述,介绍了海洋发光甲藻的种类和分布、发光的机理及其影响因素,同时对发光甲藻的应用领域及未来的研究方向进行了总结和展望。希望可以引起国内同行的重视,并为相关研究提供借鉴和参考。 相似文献
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有害藻华是海洋生态灾害中最突出的问题,威胁滨海旅游等海洋经济可持续发展。如何有效评估有害藻华对滨海旅游环境价值损失的影响,是推动生态环境保护与旅游资源开发协调发展的前提和基础。目前国内外广泛使用条件价值法,通过设置假想情景,根据受访者是否愿意为修复环境支付费用及其多少来定量转换环境损失价值。因此,受访者支付意愿及其程度是影响环境损失价值的关键参数。但是,受访者的支付意愿和最大支付额度受多种复杂因素影响,常规统计分析方法难以厘清其主要因素。本文创新性引入最大熵MaxEnt和广义相加GAMs模型,分别从是否愿意支付的定性分析和支付额度多少的定量分析两个方面,阐明厦门有害藻华影响下滨海旅游环境价值损失评估中影响这两个关键参数的主要因素。与传统统计分析方法相似,不论是MaxEnt还是GAMs模型都认为收入水平、对景点满意程度、受教育程度和年龄是解释支付意愿和支付额度的主要影响因素。但是,模型分析结果给出的显著性和重要性排序发现游客对有害藻华的科学认识确实会显著影响其支付意愿,但是对支付额度的影响有限。本文通过研究受访者对生态灾害的环境态度及其对支付意愿和支付额度的影响,为准确评估海洋生态灾害造成的环境价值损失提供科学依据。 相似文献
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Macroalgae build biogenic habitats which give shelter and provide a suitable physical environment for a great variety of organisms. Structural complexity of algal substrates may influence the composition of their attached epifauna. The aim of this study is to test whether the taxonomic relatedness of the algal hosts and the functional groups to which they belong influence the species richness and composition of their epifaunal bryozoans. We analysed 36 algal genera from the Atlantic coast of South America between 42°S and Cape Horn. Changes in bryozoan species richness (number of species) among different algal functional groups (filamentous algae, foliose algae, corticated foliose algae, corticated macrophytes) were non-significant. The composition of the epifaunal assemblages differed significantly only between filamentous and foliose algae. Sheet-like bryozoans (i.e. encrusting, pluriserial colonies) were more frequent on foliose than on filamentous algae, while runner-like species (i.e. uniserial stolons) were characteristic epibionts on filamentous thallii. Similarity of bryozoan assemblages increased with increasing taxonomic relatedness of their hosts. As most filamentous seaweeds analysed in this study are members of the Order Ceramiales, the influence of algal taxonomic relatedness and functional groups on the composition of their bryozoan assemblages can be viewed as two different aspects of the same phenomenon. 相似文献
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不同磷源对藻类生长及其生化组成的影响 总被引：13，自引：0，他引：13
在实验室培养条件下，对ＫＨ２ＰＯ４及多种溶解有机磷化合物对藻灶进行了一次性培养，考察要对ＤＯＰ的利用和不同磷源对藻类生物及其生化组成的影响。结果表明；甘油磷酸钠，６－磷酸葡萄糖，蛋黄卵磷脂和酵母核糖核酸均可被藻类吸收利用，并且培养藻类都生长良好；碱性磷酸酶在大分子ＤＯＰ利用过程中起重要作用。 相似文献
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The authors have investigated the biochemical events by which marine algal virus infection induces cell cycle arrest. The key G2/M-phase regulatory proteins are analyzed by immunobloting in unicellular Emiliania huxleyi, suggesting that virus induced cell cycle arrest is related with virus''s effect on cyclins and cyclin dependent kinases. E. huxleyi virus (EhV) represses Cdc2/cyclinB complex activity by inhibiting the activity of Cdc2 kinase in a phosphorylation-related manner, blocking host cells G2/M checkpoint. Dephosphorylated/inactive Cdc25C combined with up-regulation of Wee1 expression at early infect period appears to be important mechanisms by which EhV represses Cdc2/cyclinB complex activity that is required for entry into M phase. This study has allowed us to confirm that algal virus infection leads to selective activation or inhibition of certain cell-cycle factors, which may play a significant role in establishing a more efficient environment for viral gene expression and DNA replication. 相似文献
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Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves (Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an important aspect of managing tropical coastal systems. 相似文献
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Michael J. Sweet 《Marine Ecology》2014,35(3):343-353
Several long‐term studies have monitored populations of algal symbionts, Symbiodinium sp., in coral hosts over different temporal and spatial scales, and among multiple host species. The extension of these studies to include environmental pools of algal symbionts from sources such as the water column, sediments, free‐floating mucus mats and those settling on biofilms has only been studied by a few, yet has the potential to enhance our understanding of the dynamics and controls on symbiont populations. Adaptive changes in the coral symbiont complement rely either on the uptake of new strains from the environment or population expansion of rarer strains in the existing symbiont population. The relative scope for these alternative pathways of uptake is unknown. This study therefore examined spatial changes in Symbiodinium clades within the water column at two different time periods and compared these with other environmental pools (biofilms, sediments, and mucus mats) and those within the dominant reef‐building species at the study site, Acropora muricata. A diversity of algal symbiont clades were detected in environmental pools, with specific clades associated with different habitats. At an island scale, there was significant variation in clade composition between sites separated by 0.5–7 km, a result which was repeated for both sample periods encompassing different seasons (March 2009 and August 2010). Although no single environmental pool contained a Symbiodinium complement comparable to that of the host coral species investigated, the dominant coral Symbiodinium were available in combinations of the environmental pools, indicating that the coral has the potential to obtain its symbionts from a variety of environmental sources. 相似文献
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叶绿素浓度是衡量海洋浮游植物丰度的重要指标,快速准确地测定海水中的叶绿素含量,对于业务化监测和科学研究都具有重要的现实意义。基于活体荧光法的叶绿素传感器操作简便,可长期原位在线监测,能轻易获取大量实测数据,是当前海水叶绿素高精度测量手段的主要发展趋势。由于在海上应用时受到多种环境因素的影响,叶绿素传感器数据与实验室萃取法数值之间存在较大偏差。作者综述了科学界在浊度、光照、温度、盐度等海洋环境因素及藻类生理因素对叶绿素传感器测量的影响规律、影响机理和数据校正方法的研究进展,并对活体荧光法叶绿素传感器海上应用数据质量控制方法的研究思路进行了展望。 相似文献
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The seasonal occurrence of 94 benthic algal species, including Cyanophyta, was observed on a monthly basis over one year in the Patos Lagoon estuary (32°S, 52°W), Brazil, and showed three patterns of algal periodicity. An aseasonal group of 46 species was present throughout the year and two groups of 24 species each occurred either during summer and fall or winter and spring. The seasonal growth of 55 green, brown and red algae was correlated with monthly variations of salinity, water temperature, daylength and light radiation energy, which were measured daily in the estuary. Summer/fall peak growth was observed in 15 algae most of which correlated significantly with high salinities alone or in combination with other factors during this period. Growth peak of 11 species in winter/spring was principally a function of low water temperatures alone or together with a reduced light regime.Both periodicity of benthic algae and their seasonal growth, as a more sensitive measure of their floristic affinity, demonstrated the presence of cool temperate and tropical elements in this flora typical for warm temperate biogeographic regions. Correlations between seasonal variation of algal growth and selected environmental parameters aided in the evaluation of causal factors for algal seasonality. 相似文献
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《Estuarine, Coastal and Shelf Science》2005,62(1-2):109-117
The relationship between macroalgal assemblages and abiotic factors was quantified by gradient analyses in an area where long-term changes in macroalgal depth distributions have previously been documented. Biomass data from 4, 6, 8 and 10 m depth in an area of similar salinity (5) and substrate (rock) in the northern Baltic Proper was constrained by a set of environmental variables defining different aspects of abiotic control of species distributions (sediment cover, effective fetch, clarity index, the curvature and slope of the bottom, and direction of exposure) in multivariate analyses at different scales. Fucus vesiculosus dominated the biomass at 4, 6 and 8 m depth, and Furcellaria lumbricalis at 10 m. The applied models explained 30.7–53.3% of the total variance in community structure, and 49.3–60.9% when analysed separately for each depth. A separate analysis of species depth distributions demonstrated that effective fetch was most strongly related to upper limits of the algal belts, sediment cover to the lower limit and density of the F. vesiculosus belt, and clarity index to the lower limits of F. vesiculosus, perennial red algae, and of the red algal and Sphacelaria spp. belts. The results show a strong correlation between environmental variables and vegetation structure even on a small, local scale in the northern Baltic Proper, indicating a high suitability of the phytobenthic zone for environmental monitoring. The results add to previous studies that show a strong importance of abiotic factors on large-scale variation in phytobentic community composition in the Baltic Sea. 相似文献
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藻类是光合自养的水生孢子植物,为了适应水下弱光的特殊生境,藻类捕光天线历经亿万年的进化,形成了特殊的结构与功能。从发现藻类捕光天线的存在到至今的70多年间,其结构解析技术的发展共经历了4个阶段:首先是利用生化及普通光谱技术研究结构组成(1950?1980年);其次是利用X-ray晶体学技术研究局部精细结构(1980年至今);再次是利用电镜技术研究完整的粗略结构(1980?2010年);最后是近10年来利用冷冻电镜技术研究完整的精细结构(2010年至今)。目前以蓝藻、红藻、绿藻和硅藻为主的藻类捕光天线复合体完整的精细结构均已被解析,仅2019年就有10余种精细结构被发现。藻类捕光天线系统结构生物学的研究,不仅搭建了对结构与功能统一认识的桥梁,而且为深入揭示藻类光合作用高效能量传递机制奠定了坚实的结构基础。将藻类捕光天线系统结构和功能统一起来,进一步研究对光环境的适应性成为未来的重点,并将为藻类捕光天线蛋白在光电器件领域的应用提供充分的科学依据。 相似文献
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We report the results from a 250 km long transect, from the Danish coast to the North Sea at 55°30′ N, which was sampled every
32 km in order to study the composition and distribution of phytoplankton, and their dependence on the distance from the coast,
depth and other environmental factors. Altogether 144 species of algae were identified by light, epifluorescence and electron
microscopy. Some ecological preferences were found on the basis of measured environmental parameters and compared with the
literature. Possible controlling mechanisms for the distribution patterns of the plankton algae were analyzed by multivariate
statistics. Only distance from the coast was found to be a significant factor for algal distribution along the transect. Three
main areas of the transect were found: the coastal, middle and oceanic areas. Diatoms, mainly the centric ones, were the most
abundant group of algae. The other less abundant groups were Dinophyceae, Dictyochophyceae, Prasinophyceae and Chlorophyceae.
The pattern of distribution of diatoms and dinophytes along the transect was more or less similar, with larger numbers of
cells found close to both the eastern and western parts of the transect, although the species composition was different. Some
species were found to prefer coastal waters, other species were characterized as oceanic, and several species were found at
all stations. Porosira glacialis showed an atypical distribution along the transect, with highest abundances at both coastal and oceanic stations. 相似文献