浙江梅山湾表层沉积物中甲藻孢囊分布和多样性研究     

冷天泽  郭卓然  邵倩文  陆斗定  戴鑫烽 《海洋与湖沼》2024,55(1):145-154

甲藻孢囊可以为赤潮提供种源, 还可用于指示海区富营养化状态。以往对甲藻孢囊分布的研究多集中于开放性水域和自然形成的海湾中, 在半封闭性人工海湾中的研究较少。梅山湾原属南北开放水域, 但于2012~2017年在向陆侧建设了北坝和南坝, 使其成为半封闭式人工海湾。通过对梅山湾内外海域采集到的6份表层沉积物样品分析, 共鉴定出37种甲藻孢囊, 其丰度介于237~1 054 cysts/g。甲藻孢囊平均丰度湾内高于湾外, 推测是筑堤后湾内水动力减弱, 悬浮物质浓度降低, 水体透明度升高, 水中颗粒物质沉积速率降低和水体富营养化所导致。调查海域甲藻孢囊物种多样性指数介于1.63~2.47, 均匀度指数介于0.58~0.82, 两者湾外均显著高于湾内, 反映出湾内生态系统稳定性更弱, 发生赤潮的可能性更高。研究共检出16种赤潮种和9种有毒甲藻孢囊, 产毒种及赤潮种丰度和种类占比湾内都高于湾外, 优势种有原多甲藻(Protoperidinium sp.)、美利坚原多甲藻(Protoperidinium americanum)、透镜翼甲藻(Diplopsalis lenticula)、微小亚历山大藻(Alexandrium minutum)、链状裸甲藻(Gymnodinium catenatum)和锥状斯氏藻(Scrippsiella trochoidea)。“筑堤效应”加剧了湾内外表层沉积物中甲藻孢囊分布的差异性, 也加重了湾内有毒有害赤潮发生的风险, 故应重视对湾内有毒有害甲藻的监测。  相似文献   

实测与卫星观测德基水库水质变化   总被引：1，自引：0，他引：1       下载免费PDF全文

章国威 《水科学进展》2012,23(4):549-554

德基水库集水区的气候条件适合温带水果及高冷蔬菜、茶叶的种植,德基水库集水区上游遍布果园、菜园与茶园。因此,每逢大雨来临时,大量的残留肥料常遭冲刷至水库中。这些残留的肥料中含有大量的氮、磷等营养盐,足以提供水库微生物的生长繁殖所需,也因此造成水库中二角多甲藻的大量繁殖,进而形成藻华现象。研究使用Landsat TM卫星数据,搭配传统监测模式,以监督式影像分类法分析与监测德基水库1995年的藻华现象。研究结果显示,以Landsat TM卫星数据监测德基水库的藻华现象,其准确率可达87.5%以上。由影像分类的结果可得知,德基水库二角多甲藻之藻华现象发生较严重的时期为夏天,而冬天则较为轻微。此现象发生的原因,应与集水区上游的农业经营模式息息相关。此外,德基水库藻华现象发生的区域及其程度也经由实地调查与卫星影像监测,一一获得证实。  相似文献   

Air-sea CO₂ exchange of beach and near-coastal waters of the Chukchi Sea near Barrow, Alaska     

Hiroki Ikawa  Walter C. Oechel 《Continental Shelf Research》2011,31(13):1357-1364

Partial pressure of CO₂ in equilibrium with sample water (pCO₂) for the coastal water in the Chukchi Sea was continuously observed in summer, 2008. Average daily CO₂ flux calculated from the pCO₂ and gas transfer coefficients ranged from −0.144 to −0.0701 g C m⁻² day⁻¹ depending on which gas transfer coefficient was used. The pCO₂ before the landfast ice sheets melted appeared to be highly biologically controlled based on the following information: (1) the diurnal pattern of pCO₂ was strongly correlated with Photosynthetic Photon Flux Density (PPFD); (2) high chlorophyll density was observed during periods of peak uptake; and (3) the day-to-day variation in the pCO₂ strongly correlated with the presence or absence of near-shore ice sheets. The lowest pCO₂ of 35 ppm together with the highest PPFD of 1362 μmol E m⁻² s⁻¹ were observed in the afternoon on June 28 in the presence of sea ice. The very low pCO₂ observed in late June was likely caused by high photosynthetic rates related to high phytoplankton densities typically observed from spring to early summer near the ice edge, and by water low in salinity and CO₂ released by melting sea ice early in the season.  相似文献   

气象条件对滇池水华分布的影响   总被引：3，自引：1，他引：2  

李蒙  谢国清  鲁韦坤  戴丛蕊 《气象科学》2011,31(5):639-645

使用MODIS卫星资料,利用假彩色合成法和归一化植被指数法对滇池蓝藻水华进行监测,得到滇池水华的分布特征是：初现于5月,7月最盛,5—10月均有分布,盛时滇池水华分布区域直至南部海口一线。滇池水华分布总体北部最多,湖岸高于中心湖区,西岸高于东岸和南岸。在营养盐条件满足的条件下,高温对水华有促进作用,但不是决定因素。充足的日照是水华形成的必要条件。降水通过改变水温及日照对水华有抑制作用。小风（小于3 m/s）利于水华形成,大风对水华尤其是稀薄水华分布影响较大。气象条件通过相互影响,共同作用对水华产生影响。  相似文献   

近海浮游植物水华动力学和生物气候学研究综述     

宋洪军  季如宝  王宗灵 《地球科学进展》2011,26(3):257-265

浮游植物水华作为近海重要的生物过程,其动态变化对生态系统内的能童传递、生产力水平和各生源要素的循环等均有重要影响.随着气候变化对生态系统影响研究的深入,浮游植物水华生物气候学研究已成为当前生物海洋学研究的热点.综述了浮游植物水华的研究历史、研究方法及其发生发展的动力学机制,重点评述了气候变化对浮游植物水华动态的影响及国...  相似文献   

Are red tides affecting economically the commercialization of the Galician (NW Spain) mussel farming?     

Gonzalo Rodríguez Rodríguez  Sebastián Villasante  María do Carme García-Negro 《Marine Policy》2011

Harmful algal blooms (HABs), more specifically red tides, are among the most critical environmental factors affecting mussel cultivation in Galicia (NW Spain), and they often have been blamed for economic losses for producers. This statement is based on the correlation between days of closure of the production areas and unsold product. The present article shows that such a statement is not always correct, at least in the case of Galician mussel farming, because red tides only cause losses to producers under specific circumstances that arise from the impossibility of placing their product in the market. In addition, this article reveals the importance of finding organizational solutions within the framework of the production sector to counteract the impact of this type of phenomenon.  相似文献   

不同黏土对中肋骨条藻的絮凝去除研究   总被引：1，自引：0，他引：1  

王洪亮  曹西华  宋秀贤  俞志明 《海洋科学》2011,35(12):15-20

比较了不同种类黏土对中肋骨条藻的絮凝去除效率, 分析了黏土理化特征对絮凝去除效率的影响。结果表明, 不同种类黏土的Zeta 电位为？36.1～？15.9 mV, BET 比表面积为0.31～60.76 m2/g, 硅铝比为1.35～3.62。当黏土用量均为0.50 g/L 时, 不同黏土对中肋骨条藻的絮凝去除速度和去除...  相似文献   

紫外辐射增强对不同发育阶段荒漠藻结皮光合作用的影响   总被引：2，自引：1，他引：1  

苏延桂  李新荣  赵昕  王正宁 《中国沙漠》2011,30(4):889-893

 以腾格里沙漠东南缘自然植被区、51龄和26龄人工植被区藻结皮为研究对象,模拟研究了2%紫外辐射增强对不同发育阶段结皮叶绿素a含量(Chl-a)和净光合速率的影响。结果表明:①紫外辐射增强显著抑制了51龄和26龄人工植被区藻结皮的Chl-a含量(P<0.05),紫外辐射增强后不同发育阶段藻结皮的Chl-a含量无显著差异(P<0.05); ②紫外辐射增强显著抑制了3个植被区藻结皮的净光合速率(P<0.05),紫外辐射增强处理后,自然植被区,51龄和26龄人工植被区藻结皮的最大净光合速率分别为1.8、2.2 μmol·m-2·s-1和1.9 μmol·m-2·s-1,比对照分别下降了21%~49%,12%~22%和24%~59%。方差分析表明,紫外辐射增强后,3个发育阶段的藻结皮净光合速率无显著差异(P<0.05)。本研究表明,紫外辐射增强通过降低荒漠藻结皮的光合色素含量,减少了结皮的净光合速率,从而会对荒漠区藻结皮的生产力产生影响。  相似文献   

Soil baseline geochemistry and plant response in areas of complex geology. Application to NW Euboea,Greece     

Christos Kanellopoulos  Ariadne Argyraki 《Chemie der Erde / Geochemistry》2013

A soil and vegetation survey was undertaken in NW Euboea Island, Greece. The objectives of the study were to establish the geochemical baseline of soil and identify the impact of local geology on threshold values of potentially harmful elements. The studied area is characterized by complex geology comprising metamorphic and ultramafic rocks as well as active hot springs. A total of 117 soil samples were collected from 89 sites at depths of 0–25 cm and 25–50 cm. Eighteen vegetation samples were also collected representing prevalent indigenous perennial species in the region. Soil samples from the present study were enriched in As, Ca, Cu, Mg, Ni with concentrations reaching 233 mg/kg, 38%, 336 mg/kg, 10.8%, 1560 mg/kg respectively. Factor analysis revealed three main factors controlling the chemical composition of soil reflecting the influence of ultramafic rocks (Cr, Ca, Mg, Ni), hot spring deposits (Ca, S, Sr, As) and paedogenesis processes (Fe, Co, V, Mn, Al). The first two of these factors showed significant spatial correlation with the geological features within the study area. Subsequently, baseline concentrations based on statistical and spatial data were estimated within sub-areas reflecting the influence of local geology in soil composition. Concentrations of potentially harmful elements in the plant tissues of indigenous perennial vegetation species showed a wide range of variation from below the detection limit up to 1700 mg/kg for Ni in the hyperaccumulator Alyssum chalcidicum demonstrating that plant species have adapted to the stressful conditions caused by high elemental concentrations in soil. The results of this study can be utilized in future studies at areas of similar geology by providing an objective basis for setting realistic threshold values for pollution assessment and remediation.  相似文献   

塔里木盆地柯坪地区上寒武统表生溶蚀型藻格架白云岩的地球化学特征及意义^*          下载免费PDF全文

何凯  朱井泉  由雪莲  刘玲 《古地理学报》2013,15(1):77-94

采用野外观察、室内薄片鉴定及多项地球化学分析技术方法,对塔里木盆地柯坪地区上寒武统表生溶蚀型藻格架白云岩的特征及成因进行了研究。宏观上,藻格架白云岩呈丘状、透镜状夹于潮坪相白云岩层间,由于差异性溶蚀,发育了大量表生溶蚀孔。微观上,藻格架由富藻的泥粉晶白云石组成,而架间孔由浅色的亮晶白云石充填。藻格架泥粉晶白云石呈他形—半自形,镶嵌结构,具有暗红色—橙红色的阴极发光,较高的Na、K含量,较低的Fe含量;δ¹³C为-0.572‰～0.124‰、平均值-0.116‰,δ¹⁸O为-5.391‰～-4.983‰、平均值-5.240‰,表明其形成于准同生阶段盐度较高的相对氧化环境中。架间充填的亮晶白云石胶结物,呈半自形—自形中细晶,具有昏暗的阴极发光或者不发光,较低的Na、K含量,较高的Fe含量,δ¹³C值为-0.662‰～-0.251‰、平均值为-0.460‰;δ¹⁸O值为-6.639‰～-5.939‰、平均值-6.267‰,表明其形成于相对还原的埋藏环境。稀土元素分析结果表明,二者均具有LREE轻微富集、HREE亏损、Eu负异常特征,与海相泥晶灰岩稀土元素配分模式相似,揭示了其白云化流体均来自于原始的海水。在溶蚀作用方面,亮晶白云石胶结物相对泥粉晶白云石藻格架更易于溶蚀。前者在大气水表生溶蚀过程中,主量元素Ca、Mg丢失显著,Mg/Ca值由0.955降至0.007,微量元素Na、K丢失相对明显,Na/Ca值由原来的3.8×10^-4降为1.9×10^-4,K/Ca值由1.1×10^-3降至检测限以下,而不改变稀土元素的配分模式。这些特征表明,表生溶蚀过程在元素特征上是一个去白云化的盐度降低过程,而这一过程中基本无稀土元素的带入带出。  相似文献