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Minoru Wada Yukiko Takano Saki Nagae Yuka Ohtake Yu Umezawa Shinichi Nakamura Makoto Yoshida Yukihiko Matsuyama Mitsunori Iwataki Satoshi Takeshita Tatsuya Oda 《Journal of Oceanography》2018,74(6):587-593
Acute and severe hypoxia associated with harmful algal bloom has become one of the major causes for the environmental deterioration of coastal areas. Although it is generally thought that a large part of the dissolved oxygen consumption at a bloom site is initiated by heterotrophic bacteria that attack organic matter derived from dead or dying algal cells, precise microbial processes leading to the hypoxia are yet to be examined. Here we show temporal dynamics of extracellular dissolved organic carbon (DOC) of the red tide forming raphidophyte Chattonella marina and bacterial populations associating with the algae under laboratory conditions. During the growth of non-axenic strains of C. marina, we monitored abundance of algae, associated bacteria, and DOC in the culture media. Bacterial cell abundance increased in response to the increase in DOC both at the beginning and the late log phase of the algal growth. Flow cytometric analysis revealed that transient increase in the percentage of respiratory-active bacterial cells also coincided with the timing of the increase in bacterial abundance and DOC. These results strongly suggest that DOC released from growing C. marina fuels respiration and growth of planktonic bacteria surrounding the algae. This has implications for the role of DOC released from C. marina bloom before the collapse in mediating interactions between neighboring algae and bacterial assemblage which may eventually lead to algal bloom-associated hypoxia. 相似文献
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Technetium (Tc) biokinetics were investigated in marine macroalgae using 92mTc as tracer. Green and red algae accumulated Tc (VII) to a very low degree (CF ? 1–20); however, a much higher affinity for pertechnetate was found in some brown algal species (CF > 103). Comparative tests with different species of brown algae revealed that technetium does not accumulate similarly in all species of this group. Moreover, no significant differences in radionuclide uptake were noted between brown algae exposed to Tc in either the IV or VII oxidation states. Bioaccumulation of technetium appears to be a metabolically controlled process since uptake did not occur in heat-killed individuals and both light and temperature significantly enhanced the accumulation of technetium in brown algae. Dissection of Sargassum vulgare following the uptake phase showed that the rapidly growing air bladder, leaf-like laterals and small branches contained higher Tc concentrations and retained a greater fraction of the radioactivity than the older, cylindrical main axis. Pertechnetate retention in two brown algae was found to be significantly different; their biological half-lives for Tc differed by an order of magnitude (). During depuration, loss took place more rapidly from the younger portions of the seaweed, as evidenced by the highest concentration and greatest fraction of Tc retained in the older, cylindrical main axis. Provided certain precautions are taken, brown algae such as Cystoseira compressa and S. vulgare would serve as good bioindicator organisms for the presence of Tc contamination in marine waters. 相似文献
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《Progress in Oceanography》2007,72(2-3):137-150
Here we report on the current knowledge on the feeding ecology of the planktonic copepod Centropages typicus. We describe the foraging process of C. typicus from the detection of prey to their digestion, considering also the effects of several physical variables on the feeding activity of the species. C. typicus is an omnivorous copepod that feeds on a wide spectrum of prey, from small algae (3–4 μm equivalent spherical diameter, ESD) to yolk-sac fish larvae (3.2–3.6 mm length). It uses both suspensivorous and ambush feeding strategies, depending on the characteristics of the prey. In general, C. typicus exhibits selection for large motile prey, such as ciliates or dinoflagellates, both in nature and laboratory, and this selective pattern is enhanced under moderate intensities of turbulence. Daily rations in the field are somewhat lower than those found in the laboratory, which indicates food limitation. This fact, together with the relatively modest capacity of the species to adapt to fluctuations in food availability may explain the geographical distribution of C. typicus, being restricted to near-shelf waters. In general, it does not seem that C. typicus feeding severely impacts planktonic populations. However, the occasional importance of the species in certain ecosystems is also apparent. 相似文献
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Hidetaka Nomaki Naohiko Ohkouchi Petra Heinz Hisami Suga Yoshito Chikaraishi Nanako O. Ogawa Kouhei Matsumoto Hiroshi Kitazato 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(9):1488-1503
We conducted an in situ feeding experiment using 13C-labeled unicellular algae in Sagami Bay, Japan (water depth, 1450 m), in order to understand the fate of lipid compounds in phytodetritus at the deep-sea floor. We examined the incorporation of excess 13C into lipid compounds extracted from bulk sediments and benthic foraminiferal cells. 13C-enriched fatty acids derived from 13C-labeled algae were exponentially degraded during 6 days of incubation in the sediment. Subsequent enrichments in 13C in sedimentary n-C15, anteiso-C17, and C17 fatty acids indicated the microbial degradation of algal material and production of bacterial biomass in the sediment. We observed the incorporation of 13C-labeled algal phytol and fatty acids into foraminiferal cells. The compositions of 13C-labeled algal lipids in foraminiferal cells were different from those in the bulk sediments, indicating that foraminiferal feeding and digestion influenced the lipid distribution in the sediments. Furthermore, some sterols in Globobulimina affinis (e.g., 24-ethylcholesta-5,22-dien-3β-ol, 24-ethylcholest-5-en-3β-ol, and 23,24-dimethylcholesta-5,22E-dien-3β-ol) were newly produced via the modification of dietary algal sterols within 4–6 days. In addition to the effects of bacteria, feeding by benthic foraminifera can result in a significant reorganization of the composition of organic matter and influence benthic food webs and carbon cycling at the deep-sea floor. 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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S. Kim Juniper 《新西兰海洋与淡水研究杂志》2013,47(2):235-246
Short‐term effects of deposit feeding on benthic micro‐organisms are known from several marine environments, but longer‐term influences of deposit feeders have not been extensively investigated. The long‐term microbial response to deposit feeding by the gastropod Amphibola crenata was monitored in a 10‐month field study where deposit feeding intensity was controlled in artificial enclosures. The presence of the snail resulted in a minor decrease in bacterial numbers and a slight increase in heterotrophic activity relative to bacterial cell numbers. This effect may have been the long‐term signature of a previously reported pulse in bacterial production during the recolonisation of Amphibola faeces. Normal snail density had a strong inhibitory effect on primary productivity by the benthic microalgae, reducing CO2 fixation to 29–47% of levels that could be attained when snails were excluded. Variations in the effect of deposit feeding on micro‐organisms over the experimental period suggest that it may be modified by seasonal factors acting on benthic communities. In a similar interaction of influences, seasonal changes in microbial biomass and activity appeared to vary with snail density. 相似文献
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Jinik Hwang So Yun Park Mirye Park Sukchan Lee Yeonhwa Jo Won Kyong Cho Taek-Kyun Lee 《Ocean Science Journal》2016,51(4):599-612
In this study, seawater samples were collected from Goseong Bay, Korea in March 2014 and viral populations were examined by metagenomics assembly. Enrichment of marine viral particles using FeCl3 followed by next-generation sequencing produced numerous sequences. De novo assembly and BLAST search showed that most of the obtained contigs were unknown sequences and only 0.74% of sequences were associated with known viruses. As a result, 138 viruses, including bacteriophages (87%), viruses infecting algae and others (13%) were identified. The identified 138 viruses were divided into 11 orders, 14 families, 34 genera, and 133 species. The dominant viruses were Pelagibacter phage HTVC010P and Roseobacter phage SIO1. The viruses infecting algae, including the Ostreococcus species, accounted for 9.4% of total identified viruses. In addition, we identified pathogenic herpes viruses infecting fishes and giant viruses infecting parasitic acanthamoeba species. This is a comprehensive study to reveal the viral populations in the Goseong Bay using metagenomics. The information associated with the marine viral community in Goseong Bay, Korea will be useful for comparative analysis in other marine viral communities. 相似文献
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漂浮海藻与海藻区系的关系 总被引：1，自引：0，他引：1
区系是海藻生物地理研究的基本单位,是以一定时间、空间范围内的全部海藻为对象划分的生物地理单元,具有相对稳定的温度性质、物种组成和边界范围,且区系之间具有较明显的差异。然而,长期以来海藻的区系研究仅以定生的底栖海藻为研究对象,对于漂浮海藻则没有明确的定位。近年来世界各地漂浮海藻造成的藻华频发,在一些海域漂浮海藻已成为周期性存在,同时分子技术的发展为海藻生物地理学研究提供了有力的支撑,为追溯、比较漂浮海藻及其与定生海藻的关系提供了可靠的参考。漂浮海藻对于认识全球变化和人类活动对海藻分布、适应与进化的影响具有重要研究意义。本文结合漂浮海藻的特点和海藻生物地理学的基本研究方法探讨漂浮海藻与海藻区系的关系。 相似文献
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《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(17):1249-1263
The response of Arctic microbial communities to a variety of natural organic matter substrates, including peat, ice algae and ice-rafted debris was examined using bacterial regrowth experiments and compared to unamended controls. Bacterial growth and production were followed together with the phylogenetic composition using length-heterogeneity polymerase chain reaction (LH-PCR), and 16S rRNA gene cloning and sequencing. Intact phospholipids (IPLs) and fatty acids evaluated the relationship between lipids and bacterial community structure and the impact of varied organic substrates on microbial lipid synthesis. Differential responses to organic matter sources were observed, with ice algae supporting both higher bacterial growth and production than terrestrial-derived peat. In spite of disparate growth kinetics, the community composition remained similar in all amended incubations as was confirmed by automated ribosomal intergenic spacer analysis (ARISA). Gammaproteobacteria dominated the initial incubations, whereas in extended incubations with terrestrial peat Alphaproteobacteria dominated; in particular Sulfitobacter phylotypes closely related (>99%) to an Arctic sea-ice-associated member of the Roseobacter clade (ARK10278). Arctic bacterioplankton preferentially synthesized two phospholipids, phosphatidylethanolamine (PE) and phosphatidylglygerol (PG), with 18:0n, 18:1Δ11, 16:0n and 16:1Δ9 as the primary fatty acids. Overall, results show that organic matter source plays an important role in structuring bacterioplankton community composition, with similar IPL and fatty acid lipid distributions observed among phylogenetically distinct bacteria. 相似文献
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Two pure cultures of diatoms, a Nitzschia sp. and a Chaetoceros sp., were grown at 0°C or 10°C in the presence of two crude oils and two fuel oils. The petroleum samples were absorbed onto filter paper discs and added directly to the algal cultures. In all cases the organisms were much more sensitive to the crude oils or fuel oils when growing at 0°C than at 10°C. The rate of photosynthesis measured by an oxygen electrode for Nitzschia sp. grown and tested at 0°C was not affected during 3 hours' incubation with some four times the amount of a crude oil or fuel oil that blocked growth. The experiments lead to the cautious suggestion that psychrophilic algae will prove some fivefold more sensitive than mesophilic algae to petroleum pollution. 相似文献
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山东半岛漂浮铜藻和底栖铜藻气囊及生殖托的形态学比较分析 总被引：1，自引：0，他引：1
铜藻(Sargassum horneri)是主要分布于北太平洋西部的暖温带性海藻,是我国海藻场的重要组成物种之一,对于海洋环境、渔业资源具有重要支撑作用。除底栖生活外,铜藻可营漂浮生活。气囊和生殖托是铜藻适应漂浮生活的重要结构,但是二者与漂浮生活相适应的结构特点尚研究有限。本文对漂浮铜藻和底栖铜藻气囊、生殖托的数量以及主要形态学特征进行了统计学分析,结果显示:漂浮铜藻气囊体积显著小于底栖铜藻(P0.01),漂浮铜藻生殖托个数远少于底栖铜藻(P0.01),推测铜藻为了适应漂浮生境,其漂浮能力和有性生殖能力已经发生改变。 相似文献
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O. V. Stepanian 《Oceanology》2009,49(3):361-367
The analysis of the macroalgae distribution along the salinity gradient in the Azov Sea, the Kerch strait, and Taman Bay during the summer allowed finding two macroalgae complexes. The first complex (brackish) is formed by algae belonging to the Enteromorpha, Cladophora, Rhizoclonium, and Chaetomorpha genera in the Taganrog Gulf. The second complex (marine) with dominating algae belonging to the Enteromorpha, Chaetomorpha, Ceramium, and Polysiphonia inhabits the littoral part of the Azov Sea itself, the Kerch Strait, and Taman Bay. The saprobe analysis of the flora showed that the majority of macroalgae species inhabiting the Azov Sea are represented by meso- and polysaprobes and a small number of oligosaprobe species inhabit the Kerch Strait. The biggest species diversity of macroalgae was noted in the southwestern part of the sea; the value of Shannon’s index was 0.65 in the Taganrog Gulf, 1.04 in the Azov Sea, 1.38 in Taman Bay. The leading role in the littoral communities of Taganrog Gulf belongs to aquatic flowering plants with Potamogeton perfoliatus being dominant; as the salinity increases, the share of such species as P. pectinatus, Zostera marina, Z. noltii, Ruppia maritime, and Zannichellia major starts to increase. 相似文献
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寄生性甲藻阿米巴藻Amoebophrya是一类广泛寄生于纤毛虫类、放射虫类、甲藻类等海水浮游生物的原生生物,在北大西洋、北太平洋和地中海等营养盐丰富、宿主密度较高的河口和近海水环境中普遍存在,是海洋浮游食物网的重要组成部分。这类寄生性甲藻能够特异性感染海洋浮游甲藻,在有害藻华(harmful algal bloom,HAB)的发生过程中起下行控制作用,将逃脱了浮游动物摄食的浮游植物补充到微食物环(microbial loop)中去。Amoebophrya在近海海洋生态系统中的独特作用日益受到国际上越来越多研究者的关注和重视,并逐渐成为国际上海洋微型生物研究的新热点之一。近年来,已有初步调查研究表明这类寄生性甲藻在我国近海海域广泛存在;然而,目前我国尚缺乏该类寄生性甲藻的相关研究。本文系统综述了国际上该类寄生性甲藻的研究进展,针对目前研究中存在的问题并结合我国有害藻华发生机制相关研究的现状做出了分析和展望,以期推动我国该类寄生性甲藻的相关研究,为进一步阐释寄生性甲藻等海洋微型生物在有害藻华消长过程和海洋微食物环中的作用奠定基础。 相似文献
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The objectives of this study were to (1) investigate whether the availability of suitable zooplankton prey limits the distribution of the coastal larval areas of pike (Esox lucius) in two archipelago areas of the northern Baltic Sea and (2) compare the availability of zooplankton prey in spring between different types of coastal littoral habitat. According to the results, reed belt habitats formed by Phragmites australis constitute hot spots for zooplankton prey in the coastal ecosystem. During the spring, reed-covered shores of the inner archipelago maintained more than 10 times higher densities of copepods and cladocerans, the preferred prey for larval pike, compared to the other studied shores. Temperature conditions were also most favourable in the reed belt habitat. Thus, the reed belts of the inner and middle archipelago were shown to form the best habitat for larval pike in the coastal area of the northern Baltic Sea, and this was also the only habitat where pike larvae were found. Our results suggest that the poor survival and recruitment of pike in the outer archipelago, however, cannot exclusively be explained by sub-optimal feeding conditions of the larvae. There are also other important factors, presumably connected to the exposure to the open sea, that affect the distribution of the pike larvae. Our results, however, highlight the importance of sheltered coastal reed belt shores as reproduction habitat for spring-spawning fish in the northern Baltic Sea. Further, this study disproves the assumption that the seaweed bladder wrack (Fucus vesiculosus) forms a reproduction habitat for pike in the coastal area. 相似文献
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Echinogammarus marinus constitutes the most abundant amphipod species in Fucus spp. assemblages from many North Atlantic estuaries. However, there are some doubts about the real use of fucoids by the amphipod. Whilst some studies report the ingestion of Fucus vesiculosus by E. marinus, others suggest that the amphipod preference for fucoids is mostly related to sheltering rather than feeding, due to the high phlorotannin content of brown algae. The purpose of the present work was to disentangle this issue by checking the consumption rate and feeding preference of E. marinus on F. vesiculosus, its preferential habitat, and on Ulva intestinalis, a green algae abundant in the Mondego estuary (Western Coast of Portugal) and usually considered as highly palatable for herbivores.In a 2-stage laboratorial setup, fresh disks of the two types of algae were offered to E. marinus for three days. Consumption rates were estimated from differences between algal and animal initial and final fresh weights using a control correction factor, while preference was tested by differences in algal consumption rates when no choice was offered (stage 1) and when the two algae were offered simultaneously (stage 2).Results showed that E. marinus effectively consumed fresh F. vesiculosus in much higher amounts than U. intestinalis and significantly preferred to consume F. vesiculosus over U. intestinalis. Therefore, feeding habits must be one of the factors related to the close association of the amphipod with F. vesiculosus, although other factors may also be involved (e.g. sheltering). 相似文献
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海洋环境微生物腐蚀机理研究进展 总被引：5，自引：0，他引：5
微生物腐蚀(microbiologically influenced corrosion, MIC)是海洋环境中一种非常重要的腐蚀形式,其是微生物、环境、材料共同作用的结果,本文自MIC对海洋环境、菌株、材料性质的依赖性三个方面概述其机理的研究进展。在MIC对海洋环境的依赖性方面,突出溶解氧浓度和营养水平的影响规律与机制。在MIC对菌株的依赖性方面,首先介绍典型单菌株的腐蚀影响机制,然后分析混合菌株间不同菌株的腐蚀协同与拮抗作用,最后阐述复杂微生物群落的影响。在MIC对材料性质的依赖性方面,在总结基体化学成分与结构影响的基础上,介绍对MIC有抑制作用的典型表面的特性及其作用机制。 相似文献
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Temporal variation in cannibalistic infanticide by the shore crab Hemigrapsus oregonensis: implications for reproductive success 
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下载免费PDF全文 Larvae of benthic marine organisms are released amid high densities of suspension feeding and predatory adults and are highly subject to being consumed, even by conspecifics or their own parent. During laboratory feeding trials conducted in June 2006, female shore crabs (Hemigrapsus oregonensis) from Stege Marsh in San Francisco Bay (37°54.530′ N, 122°19.734′ W) that released their larvae during the previous 24 h ate fewer conspecific larvae than females that had not recently released larvae, though the behavior was not repeated during similar trials in 2007. Additionally, the number of larvae eaten increased with increasing starvation time, and hungrier females showed a trend toward eating more larvae from a different species (Carcinus maenas) than larvae of conspecifics. Thus, suppression of suspension feeding may reduce conspecific predation of newly released larvae, but this response partially depends on hunger level. This is the first time crabs have been shown to suppress feeding to reduce cannibalism of larvae, and this behavior could affect reproductive success and population dynamics. 相似文献