南海深海表层沉积硅藻的分布   总被引：10，自引：1，他引：10  

陆钧 《海洋地质与第四纪地质》2001,21(2):27-30

定量分析了南海36个深海现代表层沉积样品中的硅藻，发现主要的种有Thalassionema nitzschilides、Chaetoceros messanensis、Coscinodiscus modulifer、Thalassionthrix longissima、Nitzschia marina和Cyclotella spp.。根据硅藻优势种含量、丰度等特征以及Q型聚类分析，大致划分为5个组合带，它们主要受温度、上升流等环境因素的影响。  相似文献   

Gradient responses of epilithic diatom communities in the Baltic Sea proper   总被引：1，自引：0，他引：1  

Anna Ulanova  Pauli Snoeijs   《Estuarine, Coastal and Shelf Science》2006,68(3-4):661

Diatom communities and assemblages are widely used as indicators of ecological change in aquatic environments and for reconstructing palaeo-environments. Good calibration data sets, directly linking changes in diatom composition to environmental factors, are needed for building reliable gradient models with high indicative value. Such models have a broad applicability because most diatom species have cosmopolitan distributions. This paper presents community analyses of brackish-water diatoms living on submerged stones in four areas of the Baltic Sea proper along the Swedish coast. The communities on the stones were composed of epilithic, epiphytic, epipelic, epipsammic and occasionally some pelagic species. Altogether, 158 quantitative samples were taken at 41 sites between 23 April and 11 May, 1990, and the data set contained 300 diatom taxa belonging to 75 genera. Species data were analysed with principal components analysis (PCA) and environmental factors were fitted passively by multiple regression analysis on the ordination results. Differences in community composition could be explained by variation in salinity (which was correlated with N:P and Si:P ratios and the occurrence of macroalgae on the stones), nutrient concentrations and variation in exposure to wave action (which was correlated to the occurrence of soft bottoms around the stones, water temperature and the occurrence of sand grains and macroalgae on the stones). Separate analyses for small taxa (cell biovolume <1000 μm³), for large taxa (cell biovolume ≥1000 μm³) and for small and large diatom taxa together showed that diatoms of different size classes respond differently to environmental variation.  相似文献   

杂色鲍苗大规模脱落死亡的初步研究     

王瑞旋  刘广锋  徐力文  王江勇  黎伟坚  陈毕生 《海洋科学》2007,31(4):53-57

研究了杂色鲍(Haliotis diversicolorReeve)鲍苗脱落死亡周期中水质、硅藻和细菌变化情况。结果显示,鲍苗脱落前各水质指标无明显变化,脱落前硅藻数量大幅度增加,以卵形藻(Cocconeisspp.)和舟形藻(Naviculaspp.)为主要种类。同时发现一株可疑致病菌,初步鉴定为溶藻弧菌(Vibrio alginolyticus)。实验表明水质等相关因子与鲍苗脱落无直接关系,而硅藻很可能是致病菌的“载体”,整个附着膜微环境与鲍苗存亡息息相关。  相似文献   

东海陆架晚第四纪沉积硅藻及其古海洋学意义   总被引：2，自引：0，他引：2  

李超  蓝东兆  方琦 《台湾海峡》2002,21(3):351-359

本文对东海陆架DG9617岩芯沉积硅藻进行了研究，共分析鉴定出97种和变种，有近10种硅藻在岩芯中连续分布，且有较高的含量，而其余种类含量极低，仅零星检出。根据该岩芯中产出硅藻种类、含量及硅藻丰度变化特征自下而上共划分出3个硅藻组合带及5个亚带。结合孢粉资料，对产出3个不同硅藻带岩芯的地层年代进行了对比研究，表明该岩芯所代表的地层年代为中－晚全新世，硅藻I组合带大致为大西洋期的沉积，硅藻Ⅱ组合带应为亚北方期的产物，而硅藻Ⅲ组合带与亚大西洋期对应。文中并对不同硅藻组合带产出时的古海洋环境进行了初步探讨。  相似文献   

Marine diatom Thalassirosira weissflogii nutrient drawdown and its physiological status variation challenged to zinc and cadmium exposure     

LI Chundi  LONG Aimin  YAN Wen  MA Fujun  CHEN Shaoyong 《海洋学报(英文版)》2007,26(6):51-61

The uptake of zinc and cadmium by a species of marine diatom Thalassirosira weissflogii and the nutrient variation (phosphorus and silicon) in the culture medium were estimated when exposed to zinc and cadmium stress under controlled laboratory conditions.It was found that low cadmium addition could stimulate the culture to grow with a relatively high rate and exert its toxicity at the elevated concentration.The cellular uptake of zinc and cadmium by the diatom varied in the ranges of 1.21~3.75 and 0.060~0.629 fmol per cell respectively in the whole cultivation period.The mean cellular phosphorus and silicon drawdowns were constant with 0.26~0.42 and 0.30~0.46 pmol per cell respectively in those healthy cultures.It is illustrated that the algal cells can adjust some physiological mechanisms to decrease metal accumulation and keep metal homeostasis in the organism.The correlation analysis results further indicate that the cellular cadmium uptake might be closely related with the cellular phosphorus, silicon drawdown and the growth rate of diatom (P<0.05, 0.001, 0.01); and the cultures grow better in good conditions, the lower amount of phosphorus, silicon materials are consumed by a single cell to keep a high efficiency of utilization.  相似文献   

南极冰藻生化组成及其与低温适应性关系的研究   总被引：4，自引：2，他引：4  

缪锦来  石红旗  姜英辉  张波涛  侯旭光 《海洋科学进展》2002,20(4):43-50

对4种南极冰藻(2种单细胞绿藻——Pyramimonas sp．和绿藻L4，以及2种硅藻——硅藻Hl和H2)的蛋白质、脂肪、糖、无机元素含量和组成，灰分含量，以及氨基酸和脂肪酸的组成等的基本生化组成进行测定。结果表明，4种冰藻的蛋白质含量均高于常温藻，蛋白质含量以绿藻L4的含量最高，为45．18％；Pyramimonas sp．的蛋白质含量最低为27．70％。4种冰藻的脂肪含量均高于常温藻，为14．02％～l9．89％；总糖含量为4．7％～l6．3％，与常温藻含量接近。Mg的含量在冰藻和常温藻的无机元素中都为最高，为13600～l24000mg／kg，但4种冰藻的含量均低于2种常温藻；4种冰藻的灰分含量均低于常温藻，表明冰藻含有更高的有机成分。冰藻的氨基酸含量与常温藻的含量没有明显不同，但绿藻L4含有较高含量的羟脯氨酸，占总氨基酸含量的2．48％。4种冰藻的脂肪酸组成，主要以多不饱和脂肪酸为主。冰藻的基本生化组成在一定程度上反映了冰藻对生存环境的适应性，并且完全符合作为水产养殖饵料的营养要求。  相似文献   

Morphological variation of Stephanodiscus niagarae Ehrenb. (Bacillariophyta) in a Lake Ontario sediment core     

Eugene F. Stoermer  Gail Emmert  Claire L. Schelske 《Journal of Paleolimnology》1989,2(3):227-236

Stephanodiscus niagarae populations in a core from Lake Ontario show systematic variation in radial puncta number and mean valve diameter. Puncta number is stable in specimens from samples deposited between 1720 and 1844. Puncta number gradually increases in samples deposited between 1860 and 1947, then increases rapidly to high numbers in samples deposited after 1964. Mean valve diameter is relatively high in specimens from samples deposited between 1720 and 1959. Diameter of specimens deposited during this period fluctuates around a mean of 63.2 m. Mean diameter of specimens deposited from 1959 to 1980 is only 42.5 m. We conclude that the trend in puncta number reflects the time course of eutrophication in Lake Ontario. We interpret the precipitous decline in mean diameter as an indication that conditions in the lake after the late 1950's did not permit sexual reproduction in this species.  相似文献   

两种不同产量历史丰歉气象影响指数确定方法在农业气象产量预报中的对比研究   总被引：2，自引：0，他引：2  

邱美娟  刘布春  刘园  张玥滢  吴昕悦  肖楠舒  庞静漪 《气象与环境科学》2019,42(1):41-46

利用吉林省1980—2015年春玉米单产数据、50个气象站逐日气象资料,基于欧式距离和相关系数建立综合诊断指标,利用综合诊断指标研究分析预报年与历史年春玉米气象产量丰歉气象影响指数的关系,以此构建春玉米产量预报模型,对吉林省春玉米产量进行动态预报。产量预报模型对2003—2012年的预报试验结果表明,产量丰歉趋势ΔY的平均正确率均在60%以上,加权分析法的单产预报准确率除2009年外,均高于80.0%,且各时段的预报准确率均高于大概率法的。对2013—2015年吉林省春玉米产量的预报检验结果表明,加权分析法对产量丰歉趋势ΔY的预报结果稍好;加权分析法单产预报准确率几乎都在90.0%以上,普遍高于大概率法的。说明加权分析法建立的产量预报模型预报效果更好,可在业务上应用。  相似文献   

高温胁迫对河套灌区玉米生理指标及产量构成要素的影响   总被引：4，自引：0，他引：4  

王海梅 《干旱气象》2015,(1):59-62

通过设置不同梯度的温度环境,分析高温处理后玉米各项生理指标的变化情况,并对处理过的植株进行跟踪观测,分析产量构成因素的变化,确定玉米高温热害的关键温度。研究结果表明:(1)≥32℃的高温环境,对玉米各项生理指标和产量构成产生一定影响;(2)随着处理温度的升高和高温胁迫时间的延长,可溶性糖含量、可溶性蛋白含量与SOD活性均表现为先升后降的波动变化趋势,百粒重、茎秆重呈现波动下降趋势,秃尖比呈波动上升趋势;(3)38℃是多数生理指标变化的转折点,可视为玉米耐受高温的重要转折温度。  相似文献   

江南春雨和南海副热带高压的时间演变及其与东亚夏季风环流和降水的关系   总被引：3，自引：0，他引：3  

万日金  王同美  吴国雄 《气象学报》2008,66(5):800-807

使用国家气象信息中心整理的逐日降水资料和NCEP/NCAR逐日再分析资料,创建了江南春雨建立时间指数和南海副热带高压(副高)减弱时间指数,研究了江南春雨各要素的相互关系及其与东亚夏季风环流和降水的关系.分析表明,当江南春雨建立较晚时,夏季江南地区的降水也较少,这是由于东亚夏季风加强,高原近侧气旋性环流加强,使江南地区出现异常反气旋性环流(气旋性辐合环流减弱)所致;当南海副高减弱较晚时,长江中下游至江南地区降水偏多,易发洪涝,这主要是由于东亚夏季风减弱,南海副高偏强,华南的异常西南风与围绕高原的异常反气旋环流的偏北风在长江中下游流域形成异常气旋性环流所致.江南春雨的建立时间和南海副高减弱时间之间又具有线性无关性,可以为东亚夏季风环流和降水异常的预报提供重要线索.两指数与3月ENSO综合指数MEI关系密切,表明东亚的气候异常与ENSO 全球气候异常紧密联系,因此在分析预测东亚气候异常时必须同时关注全球气候异常背景.  相似文献