Interaction between macroalgae and microplastics:Caulerpa lentillifera and Gracilaria tenuistipitata as microplastic bio-elimination vectors

The pollution of microplastics(MPs)in the ocean has become a serious matter of concern.The farmed seaweeds(Caulerpa lentillifera and Gracilaria tenuistipitata)were selected to study their ability of adsorption with two typical classes of MPs(polyamides and polystyrene),thereby revealing the interaction between MPs and macroalgae and exploring novel methods of removing MPs from macroalgae.The results demonstrate that polyamides(PA)fibers had no effect on the various physiological parameters of both seaweeds(e.g.,relative growth rate,photosynthetic oxygen evolution rate,the contents of malondialdehyde and extracellular polymeric substances)after 7 days of exposure,except for the chlorophyll-a concentration.However,the effects of polystyrene(PS)particles on the algae were strongly associated with the concentration of MPs exposure.Exposed to the high concentration(100 mg/L)of PS particles,the relative growth rate of C.lentillifera and G.tenuistipitata decreased by 54.56% and 30.62%,respectively,compared to the control,while no significant(P>0.05)harmful effect of PS particles on seaweeds was observed in an environment with a low content of PS particles(25 mg/L).The PS particles in concentration of 100 mg/L significantly(P<0.05)inhibited photosynthetic oxygen evolution rate and extracellular polymeric substances(EPS)contents in both seaweeds,but increased malondialdehyde(MDA)contents.When exposed for 72 h,the MPs adhesion rate of G.tenuistipitata is higher than that of C.lentillifera,which might be due to the higher EPS content of G.tenuistipitata.The MPs desorption experiment indicated that the combination of dewatering and washing had the highest desorption rate of MPs which could reach to 91.45%and 87.23%for C.lentillifera and G.tenuistipitata,respectively.This research demonstrates the potential of macroalgae as a vector for MPs in aquatic environment and provides methodological insights into decontamination procedures for removing the MPs from macroalgae.

巨藻生物炭的制备及其去除水体中菲的应用

为了研究去除水溶液中菲(Phe),选择4种大型海藻麒麟菜、龙须菜、海带、浒苔在不同温度(300、500和700℃)下制备生物炭,并对其进行结构表征,包括元素分析、比表面积测试法(BET)、热重仪(TG)、扫描电子显微镜(SEM)和傅里叶变换红外光谱(FTIR)分析,以比较4种巨藻生物炭之间的差异.结果表明,麒麟菜生物炭(EBC500)具有最高的比表面积(271.51 m^(2)·g^(-1)),对Phe的去除率为96.36%.动力学模型拟合表明,EBC500的吸附由化学和物理吸附以及颗粒内扩散共同决定.使用Langmuir和Freundlich方程对EBC500进行拟合,拟合的R2值大于0.93.EBC500同时表现出单层和多层的吸附作用,并且其再生实验表明,Phe去除率高于98%.

大型海藻在反刍动物生产中的应用

中国海岸线长,大型海藻种类丰富,包含红藻、褐藻和绿藻。主要的栽培种类有海带、裙带菜、紫菜、龙须菜等。近年来,中国大型海藻年产量约在1 940万t。大型海藻作为一种可持续利用的海洋资源,富含蛋白质、脂肪酸、矿物质等营养物质和多糖、多酚、卤代化合物、萜类等功能性成分,这些功能性成分对反刍动物的生长发育和机体健康皆有益处,且能减少反刍动物甲烷排放,缓解全球变暖,具有无残留、无耐药性的特点,在成为绿色、功能性饲料或饲料添加剂方面极具潜力。作者就大型海藻的生物活性物质及其生理功能,以及在反刍动物瘤胃内环境调控、改善抗氧化能力和免疫性能、提升生产性能以及减少温室气体排放等方面的应用进行了综述,以期为大型海藻资源的开发与利用提供参考。

鼠尾藻生殖托不同生长阶段的附生细菌多样性研究

为探明雌雄异株大型海藻——鼠尾藻(Sargassum thunbergii)生殖组织附生细菌群落结构是否随生殖组织的生长而发生相应变化,本研究通过高通量测序技术对鼠尾藻生殖托不同生长时期的附生细菌群落进行了分析。结果显示:变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)是其核心菌门,与其他大型海藻附生细菌的组成类似;α多样性分析显示鼠尾藻生殖托生长初期阶段的附生细菌群落均匀程度更高;β多样性分析显示鼠尾藻生殖托附生细菌群落在不同生长阶段存在显著差异,且性别可能是影响鼠尾藻生殖托附生细菌群落结构组成的一个重要因素;线性判别分析效应量(Line discriminant analysis effect size, LEfSe)软件分析显示,鼠尾藻生殖托在生长初期、生长中期以及成熟期的附生微生物中分别包含11、15和4个可能与自身发育相关的生物标志物。本研究初步揭示了鼠尾藻生殖托附生细菌的多样性和复杂性,为今后精细刻画鼠尾藻藻体与其附生微生物之间相关作用的网络提供了基础数据,也为鼠尾藻的保护和利用提供了新的见解。

大型海藻微波热解制氢特性研究

大型海藻无需耕地、不含难热解的木质素,是降碳减排、生产小分子生物燃料的理想原料。对大型海藻(包括海带、蜈蚣藻、孔石莼和海黍子)进行微波热解,并与落叶松进行对比。研究了微波热解过程的升温行为、气体释放行为及氢气生成曲线,比较了微波热解的产物分布、气体组成和气化指标,进一步利用Ca-Al(CaO-Al_(2)O_(3))吸附剂原位吸收海带微波热解产生的二氧化碳(CO_(2)),强化海带的定向转化制氢。结果表明,大型海藻比落叶松具有更快的升温行为、更好的制氢效果,尤其海带的氢气产率(16.40 g/kg)为落叶松的3倍。添加Ca-Al吸附剂能够进一步增强海带的微波热解制氢效率,当海带与Ca-Al吸附剂的质量比为1.0:3.0时,氢气产率达到44.24 g/kg,气化效率可达68.57%,气体产物中氢气含量高达77.24%。

枸杞岛贻贝筏式养殖区附着藻类群落结构及其生物固碳量的估算

大型藻类是近岸海洋生态系统过程的重要驱动者之一,其潜在的碳汇作用已成为蓝碳研究领域的热点。藻类群落多样性是生态系统功能的重要驱动力,其生物量也决定了其固碳潜力。本研究在枸杞岛贻贝养殖区内设置了12个站位,对各站位养殖筏架上的附着藻类群落进行了4个季度调查。分析了各季节藻类优势种,计算了藻类群落多样性指数、单个浮子(g/个)、单位长度苗绳(g·m^(-1))上的附着藻类生物量,并根据筏架设置的规格和藻类含碳量,初步估算了筏架区附着藻类的总固碳量。基于线性回归,探讨了藻类群落多样性与生物量之间的关系,为贝类筏式养殖区附着藻类的碳汇功能评价提供了参考依据。

Comparative studies on utilizing nitrogen capacity between two macroalgae Gracilaria tenuistipitata var. liui (rhodophyta) and Ulva pertusa (chlorophyta) I. Nitrogen storage under nitrogen enrichment and starvation

This paper deals with the N storage of Gracilaria tenuistipitata var. liui and Ulva pertusa under ammonium enrichment and starvation. After 10 days of ammonium enrichment, ammonium NH4,+ free amino acid (FAA), protein (pro), chlorophyll (Chi), phycoerythrin (PE) and total dissolved nitrogen (TDN) of the two macroalgae increased significantly. Total nitrogen (TN) increased significantly from 3.65% to 5.78% dry weight of G. tenuistipitata var. liui and 2.82% to 5.07% dw of U. pertusa, respectively. Protein and FAA were the most important N storage pools in the macroalgae. During N-starvation period, individual N pools of the two species were depleted at exponential rates. Each N pool in U. pertusa decreased more rapidly than in G. tenuistipitata, var. liui and the latter was able to sustain fast growth for more time ( > 20 days) than U. pertusa. N demands for supporting growth were different between the two species, U. pertusa grew more rapidly and had higher N demands than G. tenuistipitata var. liui did.

Comparative studies on utilizing nitrogen capacity between two macroalgae Gracilaria tenuistipitata var. liui (rhodophyta) and Ulva pertusa (chlorophyta) II. Feedback controls of intracellular nitrogen pools on nitrogen uptake

The potential feedback by intracellular nitrogen pools on maximum N uptake (NH + 4) rate were determined for Gracilaria tenuistipitata var. liui and Ulva pertusa. The results of correlation matrix analyzing showed that the surge uptake of ammonium seemed related to rapid changes in small intracellular pools of inorganic nitrogen or small peptide and amino acids rather than to changes in TN content of the macroalgae. The assimilation rates of nitrogen of U. pertusa and G. tenuistipitata increased slowly during N starvation and were mainly regulated by amino acids and some incorporation of amino acids into macromolecules. From ecological point of view, the fast growing and uptaking nutrient U. pertusa is more suitable to improve water quality in integrated shrimp culture ponds in which external nutrient supplies are usually high and constant during the culture period, while G. tenuistipitata var. liui is more suitable to be polycultured in a waters with intermittence supply of nutrients.

The Distribution of Green Algal Micro-Propagules and Macroalgae at the Early Stage of Green Tide in the Coastal Area of South Jiangsu Province in 2014

An integrated investigation was carried out during late April to late May of 2014 in the coastal area of South Jiangsu Province to understand the early development of green tide in the Yellow Sea and discover the temporal and spatial distribution of green algal micro-propagules and macroalgae at the early stage of green tide. The results showed that green algal micro-propagules distributed in all stations from late April to late May, and micro-propagules of high density(> 300 ind. L^(-1)) concentrated in the adjacent Porphyra aquaculture area. Floating macroalgae were initially observed in the northern survey areas, and increased gradually. The dominant species was U. prolifera in the floating macroalgae, ranging between 90% and 100%. The seawater surface temperature and salinity in the above mentioned time period were suitable for the growth of macroalgae. This work can help government to strengthen management to reduce the blooms of macroalgae in the coastal area of South Jiangsu Province and also facilitate the decision-making for managers at the early stage of green tide.

Seasonal and spatial variation in species diversity, abundance, and element accumulation capacities of macroalgae in mangrove forests of Zhanjiang, China

The objective of this study was to investigate whether there was distinctive seasonal and zonal variation in the species diversity, biomass, and element accumulation capacities of macroalgae in two major intertidal mangrove stand types （Avicennia marina assemblage andSonneratia apetala assemblage） in the Zhanjiang region of southern China. Over a year, 31 species in 15 genera were identified in both mangrove assem-blages, of which the dominant species wereCladophoropsis zollingeriand Enteromorpha clathrat.Macroal-gal species were significantly most abundant in spring （p〈0.05）, followed by summer, winter, and autumn. Variation in the zonal distribution of macroalgal species was conspicuous in both intertidal mangrove as-semblages, with the greatest abundance in the middle zone, and the least in the front zone. Patterns in the seasonal and zonal variation in macroalgal biomass in theS. apetalaassemblage were similar to those of macroalgal species diversity in both mangrove assemblages. The seasonal patterns in tissue concentrations of 15 analyzed elements were not uniform among the macroalgaeC. zollingeri,E. clathrata, andGracilaria salicornia in theA. marina assemblage. All three species exhibited variation in their responses to ambient concentrations of different elements, implying their differential ability to absorb and selectively accumulate certain elements.

Ecophysiological characteristics of four intertidal marine macroalgae during emersion along Shantou coast of China,with a special reference to the relationship of photosynthesis and CO_(2)

Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents. The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina intermedia, and two brown algae Petalonia fascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G. intermedia and S. hemiphyllumexhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia, exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. intermedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2 concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO2 in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20 %), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation.

Physiological performance of three calcifying green macroalgae Halimeda species in response to altered seawater temperatures

The effects of seawater temperature on the physiological performance of three Halimeda species were studied for a period of 28 d.Five treatments were established for Halimeda cylindracea,Halimeda opuntia and Halimeda lacunalis,in triplicate aquaria representing a factorial temperature with 24°C,28°C,32°C,34°C and 36°C,respectively.The average Fv/Fm of these species ranged from 0.732 to 0.756 between 24°C and 32°C but declined sharply between 34°C(0.457±0.035)and 36°C(0.122±0.014).Calcification was highest at 28°C,with net calcification rates(Gnet)of(20.082±2.482)mg/(g·d),(12.825±1.623)mg/(g·d)and(6.411±1.029)mg/(g·d)for H.cylindracea,H.opuntia and H.lacunalis,respectively.Between 24°C and 32°C,the specific growth rate(SGR)of H.lacunalis(0.079%–0.110%d–1)was lower than that of H.cylindracea(0.652%–1.644%d–1)and H.opuntia(0.360%–1.527%d–1).Three Halimeda species gradually bleached at 36°C during the study period.Malondialdehyde(MDA)and proline levels in tissues of the three Halimeda were higher in 34–36°C than those in 24–32°C.The results indicate that seawater temperature with range of 24–32°C could benefit the growth and calcification of these Halimeda species,however,extreme temperatures above 34°C have negative impacts.The measured physiological parameters also revealed that H.cylindracea and H.opuntia displayed broader temperature tolerance than H.lacunalis.

DNA Barcoding Assessment of Green Macroalgae in Coastal Zone Around Qingdao, China

An assessment with assistance of DNA barcoding was conducted on green macroalgae in coastal zone around Qingdao, China, during the period of April- December, 2011. Three markers were applied in molecular discrimination, including the plastid elongation factor tufA gene, the internal transcribed spacer(ITS) region of the ribosomal cistron and rubisco large subunit gene 3' regions(rbcL-3P). DNA barcoding discriminated 8 species, excluding species of genus Cladophora and Bryopsis due to failures in amplification. We ascertained and corrected 4 species identified by morphological methods for effectively assisting the classification. The gene tufA presented more advantages as an appropriate DNA marker with the strongest amplification success rate and species discrimination power than the other two genes. The poorest sequencing success largely handicapped the application of ITS. Samples identified by tufA and rbcL as Ulva flexuosa were clustered into the clade of U. prolifera by ITS in the neighbor-joining tree. Confusion with discrimination of the complex of U. linza, U. procera and U. prolifera(as the LPP complex) still existed for the three DNA markers. Based on our results, rbcL is recommended as a preferred marker for assisting tufA to discriminate green macroalgae. In distinguishing green-tide-forming Ulva species, the free-floating sample collected from the green tide in 2011 was proved to be identical with U. prolifera in Yellow Sea for ITS and rbcL genes. This study presents a preliminary survey of green macroalgae distributed in the coastal area around Qingdao, and proves that DNA barcoding is a powerful tool for taxonomy of green macroalgae.

A mini-review on the microbial continuum:consideration of a link between judicious consumption of a varied diet of macroalgae and human health and nutrition

As the primordial,prokaryotic inhabitants on Earth,microbial entities were responsible for significant influences on the pathways taken in the development of life as we know it.The manifestation of numerous pathologies in humans is considered to be intrinsically associated with microbial dysbiosis in the gut(i.e.a poorly balanced microbiota).Such adverse health conditions include obesity,chronic fatigue syndrome,cancer,cardiovascular issues,neurological disorders,colitis,irritable bowel syndrome(IBS),and rheumatoid arthritis.Endosymbiotic events at the single cell level took place billions of years ago,eventually leading to eukaryotes,photosynthesis,and multicellularity.Macroalgae(seaweeds)were amongst the first organisms to develop these characteristics.Microbes and macroalgae interacted in a pattern of co-evolution,a process that applies to most,if not all living organisms.It is recognized that the normal human microbiome consists of over a trillion microorganisms,including about 2000 commensal bacterial species typically stationed in the gut.Many of these live in the colon,where they function in the digestion of foods,releasing bio-available nutrients,bioactive molecules,and various metabolites.They mediate communication signals between the gut and the brain,and promote the normal development of immune function,metabolic activities,behaviour,and neurological stability.As very early humans foraged for food,some would have benefi tted from coastal diets,rich in seaweeds and associated microbes.Such diets would have consistently provided all the nutrients essential for survival and growth,and as such,could have conveyed competitive advantages and contributed to enhanced cognitive sophistication.This mini-review article highlights studies regarding the health benefits of dietary fibres and the production of short chain fatty acids(SCFA).Insights are off ered regarding the positive effects the inclusion of macroalgae into the standard,Western diet can deliver in terms of providing appropriate fodder for those microbial populations deemed beneficial to human health and wellness.

Screening of antibacterial activity in marine green, red and brown macroalgae from the western coast of Libya

Marine macroalgae are considered as an excellent source of bioactive compounds which has a broad range of biological activities including antibacterial and antioxidant. Crude methanolic and water extracts of 19 marine algal species (6 Chlorophyta, 8 Phaeophyta and 5 Rhodophyta) collected from the western coast of Libya were evaluated for antibacterial activity against pathogenic bacteria (4 Gram-positive, 4 Gram-nega- tive). The extracts showed a significant antibacterial activity against Gram positive (Staphylococcus aureus, Bacillus subtilis, Bacillus spp., and Staphylococcus epidermidis) as well as Gram negative bacteria (Escherichia coli, Salmonella typhi, Klebsiella spp., and Pseudomonas aerugi- nosa). The algal aqueous and methanolic extracts displayed different degrees of antimicrobial activities against different bacteria, in some cases methanolic extracts showed higher antibacterial activity than aqueous extracts. Among tested algae, Brown algae namely Cystoseira crinite exhibited the highest antibacterial activity among tested algal species.

Macroalgae Blooms and their Effects on Seagrass Ecosystems

Seagrass decline caused by the macroalgae blooms is becoming a common phenomenon throughout temperate and tropical regions. We summarized the incidence of macroalgae blooms throughout the world and their impact on seagrass beds by direct and indirect ways. The competition for living space and using resources is the most direct effect on seagrass beds when macroalgae are blooming in an aquatic ecosystem. The consequence of macroalgae blooms(e.g., light reduction, hypoxia, and decomposition) can produce significant indirect effects on seagrass beds. Light reduction by the macroalgae can decrease the growth and recruitment of seagrasses, and decomposition of macroalgae mats can increase the anoxic and eutrophic conditions, which can further constrict the seagrass growth. Meanwhile, the presence of seagrass shoots can provide substrate for the macroalgae blooms. Controlling nutrient sources from the land to coastal waters is a general efficient way for coastal management. Researching into the synergistical effect of climate change and anthropognic nutrient loads on the interaction between searsasses and macroalgae can provide valuable information to decrease the negative effects of macroalgae blooms on seagrasses in eutrophic areas.

Sewage pollution in Negril, Jamaica: effects on nutrition and ecology of coral reef macroalgae

Coral reefs in the Negril Marine Park (NMP), Jamaica, have been increasingly impacted by nutrient pollution and macroalgal blooms following decades of intensive development as a major tourist destination. A baseline survey of DIN and SRP concentrations, C:N:P and stable nitrogen isotope ratios (δ15N) of abundant reef macroalgae on shallow and deep reefs of the NMP in 1998 showed strong P-limitation and evidence of increasing sewage pollution. In 1999, a sewage collection and treatment project began diverting wastewater from the resort and urban areas to a pond system that discharged partially-treated effluent into the South Negril River (SNR). These sewage discharges significantly increased concentrations of NH4+ and SRP (N:P ~13) in the SNR, which flows into Long Bay and around Negril’s 'West End'. Concentrations of SRP, the primary limiting nutrient, were higher on shallow reefs of the West End in 2001 compared to 1998. Stable nitrogen isotope ratios (δ15N) of abundant reef macroalgae on both shallow and deep reefs of the West End in 2002 were significantly higher than baseline values in 1998, indicating an escalating impact of sewage nitrogen pollution over this timeframe. The increased nutrient concentrations and δ15N enrichment of reef macroalgae correlated with blooms of the chlorophyte Chaetomorpha linum in shallow waters of Long Bay and Codium isthmocladum and Caulerpa cupressoides on deep reefs of the West End. Sewage treatment systems adjacent to coral reefs must include nutrient removal to ensure that DIN and SRP concentrations, after dilution, are below the low thresholds noted for these oligotrophic ecosystems.

Preference of the Herbivorous Marine Teleost Siganus canaliculatus for Different Macroalgae

The decomposition of a large amount of unexploited macroalgal resource along the coast of China often results in heavy environmental pollution. In order to pave a way of using macroalgae as the dietary ingredient of rabbitfish Siganus canaliculatus, one of a few farmed herbivorous marine teleosts in China, its preference(feeding selectivity) for different macroalgae was determined in this study. Seven seaweed species abundantly inhabiting the coast of east Guangdong Province were exposed simultaneously to rabbitfish juveniles in laboratory(multiple-choice feeding) with their content and absolute intake assayed. It was found that the most preferred algae were Ulva prolifera, Gracilaria lemaneiformis and Chaetomorpha linum, less preferred algae were U. pertusa and Porphyra haitanensis, and least preferred ones were Sargassum fusiforme and Corallina sessilis. Such an order did not change when one to four relatively preferred seaweeds were removed. The preferred seaweeds were richer in protein and soluble sugar thus higher in energy than the least preferred. In addition, this fish was found to favor filamentous and flat algae rather than calcified ones. Accordingly, the richness of nutrients and morphological characteristics determined the preference of S. canaliculatus for tested macroalgae.

Adverse Effect of TiO2 Nanoparticles on Antioxidant System and Antitumor Activities of Macroalgae Gracilaria lemaneiformis

Recently,the widespread use of TiO2 nanoparticles(nano-TiO2)has attracted the global concern regarding their adverse effects to aquatic organisms.Nanoparticles may get to the aquatic environments and harm the growth of algae.This paper presents the studies of nano-TiO2 concentrations influence on the photosynthetic characteristics,antioxidant system and antitumor activity of marine macroalgae Gracilaria lemaneiformis after exposed to 0,5,10,20 or 40 mg L^-1 of nano-TiO2.Results showed that the photosynthetic pigment content of G.lemaneiformis obviously decreased and the antioxidant defense system was significantly disturbed after exposure to nano-TiO2.Compared with control,the maximum level of malondialdehyde showed 3.3-fold increase for 15 days exposure to nano-TiO2.The activity of superoxide dismutase and catalase enhanced obviously by 1.10-2.24-fold.The aqueous extract of G.lemaneiformis(AEGL)possesses anticancer activity against HepG2 liver cancer cells proliferation and the 48 h-cell inhibition exceeds 35%.But the toxicity of nano-TiO2 would inhibit the anticancer activity of AEGL.When G.lemaneiformis was exposed to nano-TiO2,the effect of the aqueous extract of G.lemaneiformis on the cell inhibition,reactive oxygen species production,apoptosis,cycle arrest of HepG2 cells significantly lessened,and which were linearly associated with nano-TiO2 exposure concentration.Those results further confirmed that nano-TiO2 can inhibit the anticancer activity of G.lemaneiformis.The results in this work imply that macroalgae can be an effective biomarker of nano-TiO2 contaminant,and can be useful indicator to evaluate ecological effects of increasing pollutants in marine ecosystem.

The current situations of green macroalgae and micro-propagules in Pyropia aquaculture of the Subei Shoal in spring of 2013

To discover the distribution of green algal micro-propagules in the Subei Shoal and clarify the growth of green macroalgae attached on Pyropia aquaculture rafts,an integrated investigation in Pyropia aquaculture area and one cruise in the coastal area of the Subei Shoal were carried out from March to May in 2013.The results showed that green algal micro-propagules were discovered in seawater and sediment during March to May.The average quantity of micro-propagules was 267 ind./L in surface seawater and 43 ind./g in sediment.The biomass of attached green macroalgae increased in Pyropia aquaculture from March to May.Three species,including Ulva prolifera,Ulva linza and Blidingia sp.were found in Pyropia aquaculture rafts.The dominant specie was Blidingia sp.and the second was U.prolifera in spring.This study indicated that the micro-propagules and macroalgae were existed in the coastal area of the Subei Shoal at the early stage of green tide.This was the key point to the governance of green tide in China.