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1.
Abstract. This paper deals with the population dynamics of the introduced barnacle Balanus glandula in a port shelter and a rocky shore exposed of a southwestern Atlantic area. Replicated areas in both zones were denuded monthly and censused in both the high intertidal and the upper mid intertidal zone. The settlement pattern. recruitment, mortality and growth of B. glandula and a comparative successional pattern in both areas were recorded. Recruitment began in winter, i.e., July in the port and August in the rocky shore. In the port, green algae dominate up to a final community of Balanus glandula all along the intertidal, while in rocky shores the red encrusting alga Hildenbrandia lecanellieri establishes a cover that is replaced by the mytilid Brachidontes rodriguezi in the mid intertidal and by B. glandula in the high intertidal and upper mid intertidal. B. glandula densities were greater in the upper mid intertidal 19 600 and 5050 indiv. · m-2 in the port and rocky shore, respectively than in the high intertidal 13600 and 1100 indiv.· m-2, respectively. Mortality was greater in the port up to 62%, but heavy settlement allows a final density 4 times greater than in eulittoral rocky shores and 10 times greater than in the high intertidal. The winter reproduction of Balanus glandula, the absence of predators, the neutral or beneficial effect of algae. with spatial and temporal partitioning of substrate allows it to successfully outcompete mussels and other barnacle species from the intertidal community of both sheltered and exposed areas. 相似文献
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Intertidal benthic macroalgae are a biological quality indicator in estuaries and coasts. While remote sensing has been applied to quantify the spatial distribution of such macroalgae, it is generally not used for their monitoring. We examined the day-to-day and seasonal dynamics of macroalgal cover on a sandy intertidal flat using visible and near-infrared images from a time-lapse camera mounted on a tower. Benthic algae were identified using supervised, semi-supervised and unsupervised classification techniques, validated with monthly ground-truthing over one year. A supervised classification (based on maximum likelihood, using training areas identified in the field) performed best in discriminating between sediment, benthic diatom films and macroalgae, with highest spectral separability between macroalgae and diatoms in spring/summer. An automated unsupervised classification (based on the Normalised Differential Vegetation Index NDVI) allowed detection of daily changes in macroalgal coverage without the need for calibration. This method showed a bloom of macroalgae (filamentous green algae, Ulva sp.) in summer with > 60% cover, but with pronounced superimposed day-to-day variation in cover. Waves were a major factor in regulating macroalgal cover, but regrowth of the thalli after a summer storm was fast (2 weeks). Images and in situ data demonstrated that the protruding tubes of the polychaete Lanice conchilega facilitated both settlement (anchorage) and survival (resistance to waves) of the macroalgae. Thus, high-frequency, high resolution images revealed the mechanisms for regulating the dynamics in cover of the macroalgae and for their spatial structuring. Ramifications for the mode, timing, frequency and evaluation of monitoring macroalgae by field and remote sensing surveys are discussed. 相似文献
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山东半岛东端以岩基海岸为主,而浅海多为岩礁底质,适宜大型藻类生长。为探究该海域的大型藻类群落结构特征,于2018年11月(秋)、2019年2月(冬)、5月(春)和8月(夏)对山东荣成马山里海域的三个典型生境(草床区、天然礁区和泥沙区)中的大型藻类进行了调查。结果显示：三种生境共鉴定出大型藻类23种,其中红藻门15属15种,褐藻门3属4种,绿藻门3属4种。物种数最高值出现在天然礁区(22种),最低值出现在泥沙区(12种)。生物量最高值为春季草床区(1567.44±21.29)g.m-2、最低值为秋季的泥沙区(594.45±107.06)g.m-2。大型藻类优势种在不同生境、不同季节不同：草床生境为小珊瑚藻,在四个季节中均占绝对优势;礁区为绿藻向红藻、褐藻变化;泥沙区为从红藻到褐藻变化。Pielow均匀度指数的最高值在三个生境中相近且均出现在冬季;多样性指数最高值、最低值分别出现在礁区与泥沙区;Margalef丰富度指数的最高值出现在秋季的礁区,而最低值出现在夏季的泥沙区;聚类与排序结果表明,大型藻类群落结构在不同生境不同季节差异都显著。结果表明,生境特征和季节性变化是影响底栖大型海藻群落结构的主要因素。 相似文献
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底栖海藻是海洋生态系统中重要的初级生产力，开展其固碳和储碳机制研究，有利于提高对我国海域海洋固碳和储碳潜力的认识。本文基于海区条件的模拟，开展了大连海域潮间带优势海藻的日固碳量、日呼吸量和日有机碳释放量的测定，结合海区生物量的调查，阐述了3个海藻床潮间带海藻固碳和储碳的季节变化规律。结果显示:在海藻固碳能力方面，绿藻类的固碳能力最强，褐藻类次之，红藻类最低。大连海域潮间带海藻的固碳量、储碳量和有机碳释放量在12月至5月处于较高水平，6月至11月较低，平均每个海藻床潮间带区域年固碳量和年有机碳释放量分别为1.72×105 g/a和2.1×104 g/a。潮间带海藻月固碳量是储碳量的1.7倍。 相似文献
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Intertidal Invertebrate and Algal Communities on the Rocky Shores of the Bay of Morbihan, Kerguelen (South Indian Ocean) 总被引：3，自引：0，他引：3
Abstract. Both the emergent surfaces and tide pools of the rocky intertidal shores of the Bay of Morbihan, Kerguelen are depauperate in number of macroinvertebrate and macroalgal species. Diversity (H') was high and similar for macroinvertebrates in tide pools from the high to low intertidal and on the emergent surface exposed at extreme low-tide when calculated in terms of numbers of individuals. H' was lower when calculated in terms of energy and twice as high for the tide pool in the high intertidal than the lower tide-pools and the emergent surface. H' for macroalgae was 0 in the highest tide-pool and highest in the lower tide-pools. The density/species-rank curves for the macroinvertebrates and the macroalgae are logarithmic but vary in linearity. Algal biomass was 37 % of the macroinvertebrate biomass on the emergent surface at the extreme low-tide, but 106% in the highest tide-pool. Twenty-three months after denudation of the tide pools, the ratios of total densities of the macroinvertebrates (ind m-2 ) to the original densities were 48 % for the pool in the high intertidal, 25 % for the middle tide-pool, and 4 % for the pool in the low intertidal. The diversity indexes for the macroinvertebrates were similar to the original ones. Recolonization at Kerguelen is slow and shows an intertidal gradient. The composition of the rocky intertidal community at Kerguelen results from the rigorous physical environment and the small number and functional types of species. In the absence of major predators on macroinvertebrates and of herbivores on macroalgae, interaction among the species present seems to be competitive in nature. 相似文献
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Eduard A. Titlyanov Tamara V. Titlyanova Bangmei Xia Inka Bartsch 《Ocean Science Journal》2016,51(3):485-506
Retrospective analysis of diversity and species composition of marine macroalgae of Hainan Island in the period 1933–1992 is presented in this paper. There are two extensive sample collection periods of benthic macroalgae: the early collection (EC) covers a period between the early 1930s and the 1980s before considerable urbanization and reef degradation took place and a late collection (LC) was performed in 1990/1992 during a phase of rapid urbanization. Analysis of data also including an earlier published inventory of green algae covering the same collection sites (Titlyanov et al. 2011a) revealed that the marine flora of the island comprises 426 taxa in total, with 59% red algae, 18% brown algae and 23% green algae. In total 59 species of red algae, 11 species of brown algae and 37 species of green algae sampled during the LC are new records for Hainan Island. Considerable floristic changes between EC and LC became evident. In the LC there were significantly more filamentous, tubular or fine blade-like, and often epiphytic, green and red algae with a high surface-to-volume ratio. Additionally a reduction of green, brown and red algal species with larger fleshy or foliose thalli and a low surface-to-volume ratio was observed. It is assumed that the changes reflect the degradation of the coral reef ecosystem around Hainan, which was damaged by human activities especially in the 1950s–1970s. 相似文献
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Habitat modification in tidepools by bioeroding sea urchins and implications for fine‐scale community structure 
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下载免费PDF全文 By creating novel habitats, habitat‐modifying species can alter patterns of diversity and abundance in marine communities. Many sea urchins are important habitat modifiers in tropical and temperate systems. By eroding rocky substrata, urchins can create a mosaic of urchin‐sized cavities or pits separated by exposed, often flat surfaces. These microhabitats appear to harbor distinct assemblages of species. We investigated how a temperate rocky intertidal community uses three small‐scale (<100 cm2) microhabitats created by or adjacent to populations of the purple sea urchin (Strongylocentrotus purpuratus): pits occupied by urchins, unoccupied pits, and adjacent flat spaces. In tidepools, flat spaces harbored the highest percent cover of algae and sessile fauna, followed by empty pits and then occupied pits. The Shannon diversity and richness of these sessile taxa were significantly higher in flat spaces and empty pits than in occupied pits. The composition of these primary space holders in the microhabitats also varied. Unlike primary space holders, mobile fauna exhibited higher diversity and richness in empty pits than in flat spaces and occupied pits, although results were not significant. The protective empty pit microhabitat harbored the highest densities of most trophic functional groups. Herbivores, however, were densest in flat spaces, concordant with high algal coverage. These results suggest the habitats created by S. purpuratus in addition to its biological activities alter community structure at spatial scales finer than those typically considered for sea urchins. 相似文献
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Jae-Hoon Cha Kwang-Bae Kim Ji-Na Song In-Soo Kim Jeong-Bin Seo Chul-Hwi Kwoun 《Ocean Science Journal》2013,48(4):319-328
This study was carried out to learn about differences in the sessile macrobenthic fauna communities between the artificial and natural habitats. There were some differences in terms of species composition and dominant species and community structure between two habitat types. The dominant species include Pollicipes mitella and Granuilittorina exigua in natural rocky intertidal zones; Monodonta labio confusa, Ligia exotica, Tetraclita japonica in the artificial rocky intertidal zones. Among all the species, L. exotica and T. japonica occurred only in the artificial rocky intertidal zone. The results of cluster analysis and nMDS analysis showed a distinct difference in community structure between artificial and natural rocky intertidal zones. The fauna in the natural rocky intertidal zones were similar to each other and the fauna in the artificial rocky intertidal zones were divided depending on the slope of the substratum. In the case of a sloping tetrapod, M. labio confusa and P. mitella were dominant, but at the vertical artificial seawall, Cellana nigrolineata, L. exotica T. japonica were dominant. The analysis of the species presented in natural and artificial rocky intertidal areas showed the exclusive presence of 10 species on natural rocks and 12 species on artificial rocks. The species in the natural rocky intertidal area included mobile gastropods and cnidarians (i.e. rock anemones), and the species in the artificial rocky intertidal area mostly included non-mobile attached animals. The artificial novel structure seems to contribute to increasing the heterogeneity of habitats for marine invertebrate species and an increase the species diversity in rocky coastal areas. 相似文献
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Trampling by human visitors to rocky shores is a known stressor on macroorganisms. However, the effects of trampling on rocky intertidal biofilm, a complex association of microorganisms of ecological importance in coastal communities, have not been quantified. We evaluated the impact of trampling frequency and intensity on total biomass of epilithic microalgae on intertidal rocky shores in the southeast of Brazil. There was a trend of increase in the variability of biomass of biofilm in function of intensity of trampling, but no significant effects emerged among trampling treatments. The low influence of trampling on biofilm might be a result of the small dimensions of the organisms coupled with their natural resilience and roughness of the substrate; the former preventing the removal of biofilm layers by shoes and facilitating their quick recovery. Our results provide insights for management and conservation of coastal ecosystems revealing a weaker impact of trampling on biofilm than that reported on macroorganisms. 相似文献
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《African Journal of Marine Science》2013,35(4):523-531
Seagrasses support a great diversity of epiphytic organisms. There are no detailed published accounts of algae and animals growing on seagrasses in South Africa. The seagrass Thalassodendron leptocaule (previously known as Thalassodendron ciliatum) is unique among southern African seagrasses in that it occurs on exposed rocky outcrops along the Mozambican and north-eastern South African coasts; most other seagrasses are restricted to sheltered bays and estuaries. Here we present accounts of species of flora and fauna identified growing epiphytically on this seagrass in northern KwaZulu-Natal. A total of 52 taxa of macroalgae and 204 species of macroinvertebrates were identified as epiphytic on South African T. leptocaule. The most frequently observed macroalgal epiphytes were predominantly Rhodophyta and were common among periodically exposed, intertidal and subtidal habitats. The crustose red coralline algae Pneophyllum amplexifrons and Hydrolithon farinosum were frequently observed, primarily on stems and leaves of the seagrass respectively. The most diverse groups of epiphytic invertebrates were Arthropoda, Annelida and Mollusca, which together comprised 76% of the macroinvertebrate species recorded. This seagrass species is evidently an important substratum and ecosystem that supports a hidden wealth of biodiversity. 相似文献
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烟台月亮湾岩岸潮间带底栖海藻群落结构的季节变化 总被引：3，自引：0，他引：3
月亮湾岩岸潮间带底栖海藻群落的种类组成存在显著的季节差异 ,春季群落的种类最丰富 (2 7种 ) ,其次为秋季群落 (2 6种 ) ,夏季和冬季较少 (2 2和 2 1种 ) ,4个季节群落的共有种仅为 7种。各季节群落中均以红藻的种类最丰富 ,褐藻次之 ,绿藻最少。在 4个季节群落中生物量的变化如下 :夏季 >秋季 >冬季 >春季。绿藻和褐藻类群主要为暖温性种类 ,而红藻类群比较复杂 ,即有暖温带性的、温带和暖水性种类 ,也有寒温带的冷水性种类。4个季节群落的物种优势度序列存在明显的差异 ,海黍子在春季和冬季为群落的第 1优势种 ,而孔石莼在夏季和秋季为第 1优势种。不同季节群落多样性指数变化如下 :物种丰富度指数 ,春季 >秋季 >冬季 >夏季 ;物种多样性指数 ,秋季 >夏季 >春季>冬季 ;均匀度指数 ,春季 >夏季 >冬季 >秋季 相似文献
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Morgan N. Hardwick-Witman Arthur C. Mathieson 《Estuarine, Coastal and Shelf Science》1983,16(2):113-129
Quantitative sampling of the dominant intertidal epibiota was conducted seasonally along an estuarine gradient within the Great Bay Estuary System, New Hampshire, U.S.A. The abundance and zonation of the dominant macroorganisms varied with distance into the estuary. Replacement of marine by estuarine species occurred, and overall abundance and species richness decreased along the estuarine gradient. Zonation patterns within the inner estuary were primarily allied with substrata. Maximum abundance of invertebrates occurred in the mid-intertidal zone where a dense fucoid canopy provided habitat heterogeneity. Densities of epibiotic organisms decreased toward low water, especially in the inner estuary where hard substratum was limiting. Settlement blocks, introduced into the low intertidal zone, were dominated by barnacles and fucoid algae; after 16 months, the species composition on the settlement blocks resembled the adjacent community. Semibalanus balanoides settled in the spring, while Fucus vesiculosus var. spiralis exhibited low but constant settlement. Despite the physical rigors of the estuarine environment, only Semibalanus balanoides, Ilyanassa obsoleta and Spartina alterniflora showed significant seasonal changes in density. Thus, there are predictable and persistent epibiotic species assemblages within the intertidal zone of the Great Bay Estuary System. 相似文献
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Dbora Ferreira Barbosa Thelma Lúcia Pereira Dias Srgio de Faria Lopes Rafaela Cristina de Souza Duarte Fernanda Maria Duarte do Amaral 《Marine Ecology》2019,40(5)
This study investigated the community structure and functional traits of the mollusk fauna associated with macroalgae with different thallus morphologies in a reef environment in Northeastern Brazil. A total of 15 individuals of each species of macroalgae adhered to natural substrate and 15 individuals of Padina gymnospora detached from the substrate were collected. The structural complexity of algal habitats was measured and the associated malacofauna screened and identified. All three macroalgae differed significantly in the complexity of their habitat, with Sargassum polyceratium being the most complex. A total of 823 specimens of mollusks belonging to 22 species and 11 families were recorded, of which Columbellidae was the most represented with six species. The functional trait “size” revealed that micromollusks smaller than 10 millimeters were predominant in the community; however, individuals of larger sizes (up to 24.54 millimeters) belonging to young stages of other species were also present. Eight functional trophic groups were identified, of which “carnivorous” stood out with seven species. Six functional groups of microhabitats were identified, with intra‐specific variation in habitats, while habitat expansion was documented for species not yet recorded in association with macroalgae. The structure of the molluskan community differed among the three algae species with the greatest richness, abundance, and diversity of mollusks and functional traits occurring with S. polyceratium. Community structure differed between algae adhered to natural substrate and detached algae, with the latter having lower mollusk richness and diversity, but with greater abundance of some species that remained on algal fronds after release from the reef environment. This study reinforces the importance of algal habitat for marine invertebrate fauna, especially for micromollusks that spend their entire life cycle, or part of it, in association with macroalgae. 相似文献
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生活于珊瑚礁区的大型海藻可以与珊瑚一起为礁栖生物提供食物和栖息地, 它们在维护珊瑚礁生态系统生物多样性中起着极为重要的作用。本论文比较研究了生活于我国南海中沙大环礁区4种优势海藻的生化组分、光合特征及其对海水升温的生理响应,其中厚膜藻(Grateloupia ellipitica)和粉枝藻(Liagora samaensis)为红藻, 钙扇藻(Udotea flabellum)和仙掌藻(Halimeda discoidea)为绿藻。结果显示, 与绿藻相比, 红藻藻体叶绿素(Chl a)和类胡萝卜素含量更低且含有藻胆素, 红藻的光补偿点(EC)和呼吸速率(Rd)均显著低于绿藻。海水升温提高了4种海藻的光能利用效率(α)、EC、Rd和日净光合固碳量; 同时, 升温还降低红藻的饱和光强(EK)、提高绿藻的最大光合放氧速率(Pmax)。结果还显示, 海水升温在光强较低时提高红藻的光合放氧速率, 光强较高时则降低其放氧速率; 升温也提高绿藻的光合放氧速率, 但光强变化对升温效应的影响不显著。基于4种海藻的光生理特征以及升温效应的种间差异性可见, 短时间升温(~4℃)有利于中沙大环礁区海藻的光合作用; 与绿藻相比, 该升温效应更有利于红藻。 相似文献
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对嵊泗列岛岩相潮间带底栖生物种类分布进行的研究表明,种类的水平分布主要受盐度及海岸开敞度的影响,从近岸到外海,随着盐度及海岸开敞度的增加,潮间带底栖生物的种类数呈增加的趋势。不同海区的优势种不同,近岸较屏蔽区以软体动物及甲壳动物占优势,外海开敞区以甲壳动物及藻类占优势,近外海较开敞区为一过渡区;种类的垂直分布主要受潮区及海岸开敞度的影响,各海区不同潮区生物种类数均为中潮区多于低潮区多于高潮区,高潮区基本上为滨螺分布带,中潮区为日本笠藤壶－藻类带,低潮区为藻类带;外海区种类的季节变化明显,近岸区种类季节变化小。所有物种中,以底栖海藻的季节变化最为明显。 相似文献
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Emma Cebrian 《Marine Ecology》2010,31(4):533-538
Although bioerosion is among the most destructive forces on coral reefs, indirect effects influencing the bioerosion dynamics are understudied. Here, I assess the hypothesis that coral reef grazers indirectly facilitate proliferation of bioeroding sponges by removing epibiotic fleshy seaweeds from the Great Barrier Reef. This study quantifies the degree of spatial correlation between the distribution of bioeroding sponges and the distribution of grazing pressure, as evidenced by the abundance of seaweed and parrotfish bite marks. While the sponge tissue area was negatively correlated with seaweed coverage, the number of parrotfish bite marks was associated with less algae and more sponge tissue. Several factors derived from grazing on seaweeds may facilitate sponge growth: increases in the availability of light may favor primary production by symbiotic zooxanthellae and thereby increase growth of bioeroding sponges; on the other hand, sponge settlement may be facilitated on grazed substrates. All these factors are likely related, and contribute to an increasing erosion of coral reefs. Similar processes have recently been described in Mediterranean ecosystems, suggesting that the interactions I document here, could be widespread. 相似文献
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《Estuarine, Coastal and Shelf Science》2006,66(1-2):197-203
Coarse woody debris (CWD) in the intertidal region of rocky shores serves as a potential source of nutrients as well as habitat or refugia from predation, ecologically linking the adjacent marine and terrestrial habitats. In a series of field and laboratory experiments, the affinity of slow-moving motile intertidal gastropods to CWD either as food source or as shelter that increases habitat complexity was tested. In intertidal pools, CWD did not increase colonization by Littorina spp., while it did so in supratidal pools. Habitat complexity, brought about by algal cover and barnacles, was apparently sufficient in intertidal pools without woody debris, while the increase in habitat complexity by CWD increased the attractiveness of supratidal pools with little natural complexity to Littorina spp. Overall, however, comparison of pools containing woody debris and those containing artificial shelter provided evidence for CWD, and/or its biofilm, serving as food source rather than refugium per se. Similarly, Tegula funebralis chose CWD as food source rather than as shelter as indicated by comparison of autoclaved and unmanipulated woody debris. Further, both unfed and fed snails from a site where CWD was present significantly preferred CWD over macroalgae. Among snails from a site without woody debris, fed individuals showed no preference, while unfed snails significantly preferred macroalgae. From this, experience appears to be a factor that mediates the role of CWD. Overall, however, CWD appears to provide supplementary food to snails in the inter- and supratidal zone. 相似文献
20.
卫星影像是监测海面漂浮绿藻的重要数据源, 但是混合像元的存在使得绿藻提取存在一定的误差。想要实现近海区域底栖绿藻的精细监测, 需要解决绿藻亚像素覆盖度的问题。本文以厘米级分辨率无人机数据的绿藻提取结果为基准, 通过分析Landsat卫星影像绿藻光谱, 建立绿藻亚像素覆盖度与多种植被指数和多个特征波段反射率的反演模型。结果表明, 蓝、绿、红波段反射率与绿藻亚像素覆盖度呈现较好的线性关系, 随着绿藻亚像素覆盖度递增, 蓝、绿、红波段反射率的值均递减。将蓝、绿、红波段的三种绿藻亚像素覆盖模型进行验证, 发现绿波段反射率所建立的反演模型具有更高的准确性, 决定系数、均方根误差、平均相对误差分别为0.92%、0.07%、10.85%。本文所建立的模型可以估算大型绿藻亚像素覆盖度, 实现Landsat卫星影像对大型绿藻的精细监测。 相似文献