The vertical distribution of zooplankton in the western Irish Sea     

Sherard Scrope-Howe  David A. Jones 《Estuarine, Coastal and Shelf Science》1986,22(6)

Zooplankton diel vertical migration is evident on the mixed isothermal side of the western Irish Sea frontal system but is often influenced by large tides and persistent geostrophic currents. On the stratified side of the front, temperature acts as a controlling factor with most of the zooplankton occurring above the thermocline and carrying out pronounced vertical migration when chlorophyll a levels are low and diffuse. At higher chlorophyll levels, when discrete chlorophyll a maxima form, zooplankton vertical movement may be greatly modified with a large number of species and stages concentrating within these maxima at all times of the diel light cycle.  相似文献   

三门湾夏季浮游植物现存量和初级生产力   总被引：1，自引：0，他引：1  

刘镇盛  张经  蔡昱明  张志道  刘诚刚 《海洋学研究》2003,21(3):24-33

该海区的生物、化学、水文等项目进行调查。用HQM-1型有机玻璃采水器采集水样,大面观测站仅采集表层(0～1m)水样,用于测定叶绿素a质量浓度和光合作用速率。在N2和N11两个连续观测站,每隔3h采集表层和5m层的水样,用于分析叶绿素a质量浓度及营养盐浓度。同时,用浅 型浮游生物网由近底层向表层垂直拖网采集浮游植物样品,所采样品被装入容积为600cm3的塑料瓶中,并加入20cm3的福尔马林溶液固定保存,供对浮游植物细胞计数和种属鉴定之用。营养盐样品用经酸预清洗过的孔径为0.45μm的醋酸纤维膜过滤,滤液用饱和HgCl2溶液固定后,低温避光保存。图…  相似文献   

荧光法在赤潮图像分析中的应用   总被引：1，自引：0，他引：1  

王学民  孙勇  曹红宝 《海洋通报(英文版)》2006,8(1):75-82

赤潮藻样品中往往包含着各种复杂的非藻沉淀物,为解决这些微藻的探测和分析的问题,可以利用微藻类在一定波长的光照射下会产生荧光的特性,对裸甲藻等多种赤潮藻类进行荧光实验处理,并在此基础上对藻类的荧光图像和灰度图象进行图像分割,轮廓和纹理分析及图象识别等后继图象处理。实验证明,荧光法可以有效的去除背景噪声,保留藻类信息,使得后继的图象处理工作更加容易和有效,从而解决了探测和分析包含复杂背景的沉淀物样品中微藻的问题。  相似文献   

基于荧光原理的叶绿素a传感器校准方法研究     

《海洋技术学报》2024,(1)

利用传感器对水体叶绿素a 浓度进行原位测量是获取实时、连续、长时间序列数据的重要手段。本文在对RBR 传感器和ECO（Environmental Characterization Optics）传感器进行原理分析和线性度、稳定性、重复性等基本性能测试的基础上，利用单一藻种培养液和2020年南海北部海域现场数据校准传感器，并对新的传感器校准系数进行验证。结果表明：两台传感器使用新系数比原出厂系数的叶绿素a 浓度测量准确度有明显提高。RBR 传感器现场数据校准系数的计算结果与叶绿素a 标准值误差最小，平均绝对误差从1.93 μg/L 减小到0.35 μg/L，平均相对误差从55.1%减小到10.9%；ECO 传感器藻液系数明显优于出厂系数和现场数据校准系数的计算结果，平均绝对误差从1.76 μg/L 减小到0.59 μg/L，平均相对误差从50.3%减小到15.1%。传感器测量准确度的提高，可为海洋环境监测、海洋生态灾害预警等工作获取真实可靠数据提供支撑。  相似文献   

Hydrography and phytoplankton of waters off south-west Ireland     

R. Raine  J. O'Mahony  T. McMahon  C. Roden 《Estuarine, Coastal and Shelf Science》1990,30(6)

Distributions of physical, chemical and biological characteristics were recorded for coastal waters off south-west Ireland during the summers of 1985–1987. A number of thermal fronts were identified from both shipboard measurements and satellite imagery. Upwelling was shown to be an important process in the area and enhanced phytoplankton biomass and productivity were associated with areas of upwelling and the fronts. Phytoplankton species composition, although varying between cruises, was associated with differences in hydrographic features.  相似文献   

Phytoplankton biomass and size fractions in surface waters of the Australian sector of the southern ocean     

Wendy Ehnert  C. Peter McRoy 《Journal of Oceanography》2007,63(2):179-187

We collected surface water along the 142nd E meridian from Tasmania to Antarctica in December 1999. We measured temperature, salinity and total chlorophyll a; additionally, we collected suspended particle size fractions and used fluorometric analysis to determine the quantity of chlorophyll a in each of four cell size classes: picoplankton (<3 μm), two nanoplankton fractions (3–10 μm and 10–20 μm) and microplankton (> 20 μm). Changes in temperature and salinity show that we crossed 6 water masses separated by 5 fronts. We found low abundance (<0.2 mg m⁻³) of chlorophyll in all size classes, with the exception of higher values near the continent (0.2 to 0.4 mg m⁻³). Lowest chlorophyll values (<0.1 mg m⁻³) were found in the Polar Frontal Zone (51° to 54°S). Microplankton made up the largest portion of total chlorophyll throughout most of the region. We conclude that biomass of all phytoplankton fractions, especially pico-and nanoplankton, was constrained by limiting factors, most probably iron, throughout the region and that ecosystem dynamics within a zone are not circumpolar but are regionalized within sectors.  相似文献   

Small-scale variability of zooplankton pyruvate kinase activity in the Gironde Estuary plume (Atlantic French Coast): A case study under unusually low freshwater discharge   总被引：1，自引：0，他引：1  

Jean-Pierre Bergeron   《Estuarine, Coastal and Shelf Science》2006,69(3-4):662

Pyruvate kinase (PK) activity measurements are used to assess the role of carbohydrates in global feeding of mesozooplankton communities inhabiting an estuary plume. As a consequence of a remarkably low freshwater discharge rate, the sea surface layers of the area under estuarine influence showed a very moderate salinity fall and a nearly total depletion in nitrates, whereas higher levels of these nutrients were found in deeper, more saline, layers. Small-scale PK activity variations in mesozooplankton appear to be closely correlated to nitrate integration values within the water column. The results were analysed in comparison with literature reports. The study produced a coherent overall interpretation, which strongly supports the reliability of this new biochemical tool in detecting assimilation of trace carbohydrates in the diet of mesozooplankton.  相似文献   

Influences of Nutrient Outwelling from the Mangrove Swamp on the Distribution of Phytoplankton in the Matang Mangrove Estuary, Malaysia   总被引：1，自引：0，他引：1  

Katsuhisa Tanaka  Poh-Sze Choo 《Journal of Oceanography》2000,56(1):69-78

Distributions of dissolved nutrients and Chl. a were investigated in the Sangga Besar River Estuary in the well-managed Matang Mangrove Forest in West Malaysia. In the estuary, spring tide concentrations of ammonium, silicate and phosphate were higher than those in the neap tide, which suggests that these nutrients are flushed from the mangrove area by the inundation and tidal mixing of the spring tide. Ammonium comprised over 50% of the dissolved inorganic nitrogen in the spring tide, while nitrite tended to dominate in the neap tide, indicating the predominance of nitrification inside the estuary in neap tides. Nutrient concentrations in the creek water were higher than those of estuarine water, indicating the nutrient outwelling from the mangrove swamp and ammonium regeneration from mangrove litter in the creek sediments. The maximum concentration of Chl. a in spring tides reached 80 g/l while it was below 20 g/l in the neap tides. These variations in the phytoplankton biomass and nutrients probably reflect the greater nutrient availability in the spring tide due to outwelling from the mangrove swamp and creek.  相似文献   

Beneath the surface: Characteristics of oceanic ecosystems under weak mixing conditions – A theoretical investigation     

Aike Beckmann  Inga Hense   《Progress in Oceanography》2007,75(4):771-796

This study considers an important biome in aquatic environments, the subsurface ecosystem that evolves under low mixing conditions, from a theoretical point of view. Employing a conceptual model that involves phytoplankton, a limiting nutrient and sinking detritus, we use a set of key characteristics (thickness, depth, biomass amplitude/productivity) to qualitatively and quantitatively describe subsurface biomass maximum layers (SBMLs) of phytoplankton. These SBMLs are defined by the existence of two community compensation depths in the water column, which confine the layer of net community production; their depth coincides with the upper nutricline. Analysing the results of a large ensemble of simulations with a one-dimensional numerical model, we explore the parameter dependencies to obtain fundamental steady-state relationships that connect primary production, mortality and grazing, remineralization, vertical diffusion and detrital sinking. As a main result, we find that we can distinguish between factors that determine the vertically integrated primary production and others that affect only depth and shape (thickness and biomass amplitude) of this subsurface production layer. A simple relationship is derived analytically, which can be used to estimate the steady-state primary productivity in the subsurface oligotrophic ocean. The fundamental nature of the results provides further insight into the dynamics of these “hidden” ecosystems and their role in marine nutrient cycling.  相似文献   

三角帆蚌对水体悬浮物和叶绿素a消除量的研究   总被引：17，自引：0，他引：17  

费志良  潘建林  徐在宽  丁健  张健 《海洋湖沼通报》2005,(2):40-45

本研究在不同温度条件下分别测定了一龄(△1)和三龄(△3)三角帆蚌对水体中悬浮物和叶绿素a的消除量;研究了三角帆蚌对叶绿素消除效果与水体中藻类生物量之间的关系,并在池塘中挂养1200只三角帆蚌四个月。结果表明:三角帆蚌对水体中悬浮物和叶绿素a的消除率均随水温升高而提高,其中消除效果在总重量相同时△3>△1,较高水温条件下三角帆蚌在悬浮物中优先利用藻类;同一温度下,水体中藻类量增大时,三角帆蚌对叶绿素a的消除量增大而消除率却降低;在池塘挂养测试中与对照池塘比较,四个月后三角帆蚌因大量消除了池塘水中的悬浮物和叶绿素a,使池塘水体透明度提高从26cm提高到了80cm。  相似文献