Laser-Dye Imaging of the pH Field in a Laboratory Experiment

We established a precise DeLIF (Dual Emission Laser Light Fluorescence) system for the instant measurement of the pH field in laboratory experiments. This method is very important in studies of the biological impacts of CO₂ sequestration, i.e., effects of pH on organisms. The technique is demonstrated by applying it to the pH measurement around a liquid CO₂ droplet, which has a large gradient of CO₂ concentration near its interface, the concentration value on the boundary being known as the solubility of CO₂. In the Laser Induced Fluorescence (LIF) method using quinine and an ultraviolet laser light source, the relatively unstable pulse of the laser source decreased the measurement reliability. We therefore investigated many kinds of fluorescent dye and demonstrated the DeLIF measurement, identifying a process for cancelling fluctuations of laser light intensity. Quinine and sulforhodamine were used as fluorescence dyes. The molar absorption coefficient and emission intensity of quinine depend on the pH of aqueous solutions, while those of sulforhodamine are not as much affected by pH. The ratio of these fluorescence intensities represents pH at each point of the image. As a result, the pH field was successfully measured with an uncertainty of only approximately ±0.005, for 3.0 < pH. This revised version was published online in July 2006 with corrections to the Cover Date.     

The transition zone chlorophyll front can trigger <Emphasis Type="Italic">Acanthaster planci</Emphasis> outbreaks in the Pacific Ocean: Historical confirmation

We hypothesize that the North Pacific transition zone chlorophyll front (TZCF) can episodically deliver enhanced phytoplankton levels that are linked to the emergence of adult populations of the coral eating starfish Acanthaster planci. In some years, the seasonally migrating TZCF bathes the northwest Hawaiian Islands with chlorophyll-a rich waters during the winter months that coincide with peak starfish spawning and provide ideal conditions for A. planci larval survival. We found significant relationships between starfish populations in the North Pacific and the southernmost latitude of the TZCF, chlorophyll-a concentrations, sea surface temperature, and Ekman transport indices since 1967. We propose that TZCF-triggered primary outbreaks are followed by secondary outbreaks throughout the region, in accordance with the surface currents and separated by a sequential time lag. Our historical confirmation suggests outbreaks are predictable, which has immediate coral reef conservation and management consequences.     

莱州湾及潍河口夏季浮游植物生物量和初级生产力的分布

于1998年6月黄河断流期在潍河口及其邻近海域进行了水文、化学和生物等专业综合外业调查.对此海区浮游植物叶绿素a浓度、脱镁色素浓度和初级生产力的变化进行了分析.研究结果表明,叶绿素a浓度介于0.089～5.444mg/m3之间,平均值为1.331mg/m3;脱镁色素浓度介于0.176～3.402mg/m3之间,平均值为0.905mg/m3.叶绿素a和脱镁色素浓度高密度区分布在小清河口附近、潍河口内及潍河口以外临近海域.初级生产力介于13.58～301.54mg/(d·m2)之间,平均值为62.49mg/(d·m2).水柱初级生产力高值区分布在小清河口和37.30°N,119.47°E附近.对水文、化学和浮游动物等环境因子与浮游植物生物量和初级生产力的相关性分析表明,整个调查区,浮游植物生物量和初级生产力与海区潮汐、光照、磷酸盐、硅酸盐和微型浮游动物等环境因子密切相关,同氨盐、硝酸盐和亚硝酸盐的作用不明显,其中潍河口内浮游植物的生物量分布同潮汐的关系最为密切.夏季此海域浮游植物生长主要受磷酸盐和硅酸盐的限制.调查海域浮游植物生物量及生产力水平较历史同期有所增加.     

Natural organics as fluorescent tracers of river-sea mixing

The use of dissolved organic matter fluorescence as a tracer of river-sea mixing was examined in two South Carolina estuaries. Fluorescence declined linearly with seawater dilution in laboratory mixing studies, and also behaved conservatively in an estuary where a single river emptied into a bay. Fluorescence-salinity relationships were also studied in another estuary where a piedmont river (high suspended sediment, low fluorescence) and a coastal plains river (low sediment, high fluorescence) mixed with ocean water. The factor of 2 or greater difference in fluorescence between the two rivers allowed their relative contribution to the estuarine water mass to be distinguished. Petroleum hydrocarbons, measured in estuarine water at 0·7-1·8 μg l⁻¹ concentrations, contributed negligibly to water fluorescence.     

黄海冷水团上升流对叶绿素垂向分布的影响

利用黄海冷水团物理-生态耦合模式，对冷水团水域叶绿素垂向分布的季节变化进行了数值模拟研究。物理模式为冷水团热动力模型，生态模式主要考虑叶绿素，营养盐和食植浮游动物基本状态变量的耦合方程。研究结果表明，黄海冷水团上升流对叶绿素垂向分布的夏季上层结构具有显著影响。整个夏季，受上升流的影响，叶绿素垂向分布最大值的位置向海面抬升，量值增大，混合层叶绿素的平均浓度增加，与实测资料比较表明，考虑冷水团上升流的影响比不考虑上升流与实测结果符合要好。     

NaCl胁迫下小麦幼苗叶绿素含量生物量及12种元素的累积与分布

用不含ＮａＣｌ和含０．２％，０．４％，０．８％及１．０％ＮａＣｌ的溶液处理小麦１４ｄ，分别测定其根，茎，叶的１２种元素含量，叶绿素含量和生物量，随着盐度的增加，麦全株和各器官的Ｎａ＾＋含量逐步上升，而叶绿素含量，碳含量和生和的量逐步降低，对５种大量元素的吸收也逐步下降。     

浮游植物粒级研究方法的比较

基于 2 0 0 1年 8月胶州湾浮游植物综合调查资料 ,对显微测量粒径分析法、叶绿素 a粒级分离法、电子粒度分析仪法这 3种浮游植物粒级结构研究方法进行了初步比较 ,以期为较准确研究浮游植物的粒级结构提供科学依据。发现 ,当调查区内优势种为小细胞种类的链状群体时 ,使用叶绿素 a粒级分离、电子粒度分析仪法区分粒径的结果会低估小细胞的种类。用显微测量粒径分析法 ,测量出各种类的粒径参数 ,可以较准确地推算出浮游植物群落粒级结构。这对浮游植物群落的粒级结构分析是 1个必要的补充     

Validation of ADEOS-II GLI ocean color products using in-situ observations

The Global Imager (GLI) aboard the Advanced Earth Observing Satellite-II (ADEOS-II) made global observations from 2 April 2003 to 24 October 2003. In cooperation with several institutes and scientists, we obtained quality controlled match-ups between GLI products and in-situ data, 116 for chlorophyll-a concentration (CHLA), 249 for normalized water-leaving radiance (nLw) at 443 nm, and 201 for aerosol optical thickness at 865 nm (Tau_865) and Angstrom exponent between 520 and 865 nm (Angstrom). We evaluated the GLI ocean color products and investigated the causes of errors using the match-ups. The median absolute percentage differences (MedPD) between GLI and in-situ data were 14.1–35.7% for nLws at 380–565 nm, 52.5–74.8% nLws at 625–680 nm, 47.6% for Tau_865, 46.2% for Angstrom, and 46.6% for CHLA, values that are comparable to the ocean-color products of other sensors. We found that some errors in GLI products are correlated with observational conditions; nLw values were underestimated when nLw at 680 nm was high, CHLA was underestimated in absorptive aerosol conditions, and Tau_865 was overestimated in sunglint regions. The error correlations indicate that we need to improve the retrievals of the optical properties of absorptive aerosols and seawater and sea surface reflection for further applications, including coastal monitoring and the combined use of products from multiple sensors.