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21.
Rosie Chance Alex R. Baker Frithjof C. Küpper Claire Hughes Bernard Kloareg Gill Malin 《Estuarine, Coastal and Shelf Science》2009
A number of field and laboratory studies on the impact of marine macroalgae on dissolved inorganic iodine speciation are presented. Within tidally isolated rock pools, the brown macroalga Fucus serratus was found to both release stored iodide and to facilitate the reduction of iodate to iodide. In contrast, no discernible changes in iodine speciation were observed in rock pools containing green macroalgae of the genus Ulva. Incubation experiments confirmed that the macroalgae Laminaria digitata, F. serratus and Kallymenia antarctica release iodide, though the rate of release varied between species and between specimens of the same species. Application of oxidative stress by treatment with cell wall derived oligoguluronate elicitors increased the efflux of iodide by L. digitata approximately 20-fold. The release of iodide by macroalgae may impact upon the formation of volatile iodine species (molecular iodine and iodocarbons) that are of importance in the coastal atmosphere. 相似文献
22.
Toward assessing the biogeochemical significance of seaweeds in relation to dissolved iodine in seawater, the effect of whole seaweeds (Laminaria digitata and Fucus serratus) upon iodide and iodate, at essentially natural concentrations, has been studied. The weeds were carefully removed from the sub-littoral zone of the Menai Straits and exposed to iodide and iodate at their natural temperature (6 °C), but under continuous illumination. Laminaria digitata was found to decrease the concentration of iodate with an exponential rate constant of 0.008–0.24 h−1. This is a newly discovered process which, if substantiated, will require an entirely new mechanism. Generally, apparent iodide concentration increased except in a run with seawater augmented with iodide, where it first decreased. The rate constant for loss of iodide was 0.014–0.16 h−1. Meanwhile, F. serratus was found not to decrease iodate concentrations, as did L. digitata. Indeed, after ∼30 h iodate concentrations increased, suggesting that the weed may take in iodide before oxidising and releasing it. If substantiated, this finding may offer a way into one of the most elusive of processes within the iodine cycle – iodide oxidation. With both seaweeds sustained long-term increases of apparent iodide concentration are most easily explained as a secretion by the weeds of organic matter which is capable of reducing the Ce(IV) reagent used in determination of total iodine. Modelling of the catalytic method used is provided to support this contention. The possibility of developing this to measure the strain that seaweeds endure in this kind of biogeochemical flux experiment is discussed. A Chemical Oxygen Demand type of approach is applied using Ce(IV) as oxidant. The results of the iodine experiments are contrasted with the several investigations of 131I interaction with seaweeds, which have routinely used discs of weed cut from the frond. It is argued that experiments conducted with stable iodine may measure a different variable to that measured in radio-iodine experiments. 相似文献
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2013年6月-2014年6月对青岛岩礁潮间带鼠尾藻、孔石莼、蜈蚣藻附植小型底栖生物进行了连续13个月的逐月采样,对小型底栖生物的丰度、生物量、生产量、类群组成及其季节动态进行了研究。共鉴定出小型底栖生物16个类群。鼠尾藻附植小型底栖生物的年平均丰度和生物量分别为7×103 ind·g-1 dwt algae·a-1和56×103μg·g-1 dwt algae·a-1。孔石莼附植小型底栖生物的年平均丰度和生物量分别为2×103 ind·g-1 dwt algae·a-1和8×103μg·g-1 dwt algae·a-1。蜈蚣藻附植小型底栖生物的年平均丰度和生物量分别为3×103 ind·g-1 dwt algae·a-1和16×103μg·g-1 dwt algae·a-1。三种藻类附植小型底栖生物平均丰度和生物量的高低依次为:鼠尾藻蜈蚣藻孔石莼。附植小型底栖生物及其主要类群的丰度具有明显的季节变化,其中鼠尾藻、孔石莼附植小型底栖生物丰度与海水温度和盐度显著相关。附植小型底栖生物的丰度还可能与藻类生长周期关系密切,三种藻类附植小型底栖生物的丰度的最高值均出现在藻类的快速生长期之前。三种藻类附植小型底栖生物群落差异显著,鼠尾藻上线虫为最优势类群,孔石莼和蜈蚣藻上底栖桡足类为最优势类群。藻类形态和藻类生活周期是影响附植小型底栖生物类群组成、丰度和生物量的关键因素。 相似文献
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《中国海洋大学学报(自然科学版)》2000,30(Z1):71-79
1988年5月在青岛沿海潮间带采集了海水、沉积物、海 藻和一些常见的底栖动物样品,用原子吸收分光光度法测定Cu含量。结果表明:海水中Cu含 量低于一类海水标准,说明该海域海水Cu污染不明显;与国内外一些海域比较,沉积物Cu含 量较低;海藻中海头红、鸭毛藻和异管藻Cu含量较高,Cu含量较低的是石花菜、裙带菜和海 膜;底栖动物Cu含量排序为:贻贝>褶牡蛎>短滨螺。底栖动物对Cu的富集能力远大于海藻, 两者富集系数相差近10倍。 相似文献
26.
You Ah Kim Chang Suk Kong Young Ran Um Jung Im Lee Taek Jeong Nam Youngwan Seo 《Ocean Science Journal》2008,43(1):31-37
As a part of an ongoing search for antioxidants frodm marine sources, antioxidant activities of 24 kinds of seaweeds (4 green
algae, 8 brown algae, and 12 red algae) were investigated. The seaweeds were extracted by acetone/ dichloromethane and methanol,
respectively. The antioxidant properties of both extracts were evaluated using four different activity tests, including degree
of occurrence of intracellular reactive oxygen species (ROS), NO, lipid peroxidation, and GSH (glutathione) in mouse macrophage
Raw 264.7 cells. The levels of intracellular reactive oxygen species (ROS) and GSH were measured using 2’,7’-dichlorofluorescin
diacetate (DCF-DA) and monobromobimane as fluorescence probe, respectively. Moreover, the generation of NO and lipid peroxidation
products were determined by each method based on the Griess reaction and TBARS assay. Solvent extracts from seaweeds such
asScytosiphon lomentaria, Prionitis cornea, Laruencia okamurae,Callophyllis japonica, Sargassum horneri, Dictyopteris divaricat a,Lomentaria catenata, Corallina confuse, Ishige okamurae, andAhnfeltiopsis flabelliformi exhibited high antioxidant activities in cellular oxidizing systems. 相似文献
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Stability of some New Zealand coastal inlets 总被引:1,自引:1,他引:0
R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(4):449-457
The relation of tidal compartments to entrance cross‐sectional areas is examined for 20 coastal inlets. Sixteen inlets conform to a linear relationship, which is consistent with stable entrances the sizes of which are determined by the ability of the tidal flow to transport sediment. Based on this criterion deposition should be taking place at the entrances of the other four inlets: Wellington, Lyttelton, and Akaroa harbours, and Paterson Inlet. Available data confirm this for Wellington and Lyttelton Harbours. 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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The putative impacts of the non‐native seaweed Sargassum muticum on native communities in tidepools of Southern California and investigation into the feasibility of local eradication 下载免费PDF全文
Jayson R. Smith 《Marine Ecology》2016,37(3):645-667
The ecological impacts of introduced seaweeds have been relatively understudied. Current research suggests that seaweed invasions often result in alterations of native marine communities and disruptions of normal ecosystem functioning, but the effects on native communities can vary among invasive seaweed species, among habitats and over small and large spatial scales. In this study, the impacts of Sargassum muticum, a non‐native brown alga introduced into southern California, USA, several decades ago, were examined by comparing community structure in rocky inter‐tidal pools with and without the seaweed. Sargassum muticum appeared to have little impact on the native community despite measures revealing changes in the abiotic conditions of pools, with S. muticum presence reducing light penetration and ameliorating pool temperature changes during low tides. In other regions and habitat types, S. muticum presence often, but not consistently, resulted in declines in macrophyte diversity and/or abundance and increases in faunal assemblages. The lack of effects of S. muticum in this study, combined with variable impacts by S. muticum and other invasive seaweeds worldwide, suggests that predicting the effects of introduced seaweeds is problematic and warrants further research. Regardless of the effects on native communities, there is often a desire to eradicate or control the spread of non‐native seaweeds. In this study, localized S. muticum eradication attempts, including manipulations of a native canopy and herbivorous urchins, proved unsuccessful as full recovery occurred in ~9 months. While eradication efforts conducted worldwide have resulted in mixed success, there is a trend that early detection and rapid response can increase success, highlighting a need for systematic monitoring and establishment of regional rapid response plans. 相似文献
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The exploitation of different plant materials for the biosynthesis of nanoparticles is considered a green technology because it does not involve any harmful chemicals. In this study, iron oxide nanoparticles (Fe3O4-NPs) were synthesized using a completely green biosynthetic method by reduction of ferric chloride solution using brown seaweed water extracts. The two seaweeds Padina pavonica (Linnaeus) Thivy and Sargassum acinarium (Linnaeus) Setchell 1933 were used in this study. The algae extract was used as a reductant of FeCl3 resulting in the phytosynthesis of Fe3O4-NPs. The phytogenic Fe3O4-NPs were characterized by surface plasmon band observed close to 402 nm and 415 nm; the obtained Fe3O4-NPs are in the particle sizes ranged from 10 to 19.5 nm and 21.6 to 27.4 nm for P. pavonica and S. acinarium, respectively. The strong signals of iron were reported in their corresponding EDX spectra. FTIR analyses revealed that sulphated polysaccharides are the main biomolecules in the algae extracts that do dual function of reducing the FeCl3 and stabilizing the phytogenic Fe3O4-NPs. The biosynthesized Fe3O4-NPs were entrapped in calcium alginates beads and used in Pb adsorption experiments. The biosynthesized Fe3O4-NPs alginate beads via P. pavonica (Linnaeus) Thivy had high capacity for bioremoval of Pb (91%) while that of S. acinarium (Linnaeus) Setchell 1933 had a capacity of (78%) after 75 min. The values of the process parameters for the maximum Pb removal efficiency by Fe3O4-NPs alginate beads synthesized via P. pavonica (Linnaeus) Thivy were also estimated. 相似文献