An optimized method for automated analysis of algal pigments by HPLC

A recent development in algal pigment analysis by high-performance liquid chromatography (HPLC) is the application of automation. An optimization of a complete sampling and analysis protocol applied specifically in automation has not yet been performed. In this paper we show that automation can only be successful if the various methodological aspects of the sampling and analysis protocol are considered in coherence. We introduce an optimized protocol that involves freeze-drying of the sample, subsequent extraction in 90% acetone and the application of water-packing during analysis. The method was evaluated on both natural plankton populations and a broad spectrum of microalgal cultures: Thalassiosira weisflogii (Bacillariophyceae), Emiliania huxleyi (Prymnesiophyceae), Phaeocystis globosa and Phaeocystis antarctica (Prymnesiophyceae) and Pyramimonas sp. (Prasinophyceae). Whereas pigment extracts were unstable in methanol, with recorded chlorophyll a losses from 10% to 60% per day, pigment degradation rates in acetone were generally less than 1% over 18 h storage in the autosampler (4 °C). In addition, it was found that the extraction efficiency of acetone significantly increased upon freeze-drying prior to extraction. Increases as high as 50–60% were measured in P. antarctica. The application of water-packing of the sample during injection resulted in improved peak shape and peak separation, without diluting the pigment concentrations. Automation is especially beneficial for application in the field, when mixed algal assemblages and low biomass put a high demand on the sensitivity as well as reproducibility of the method.     

云南程海近500年来湖泊初始生产力的演化

程海为富营养化封闭湖泊，通过对程海CH01乳沉积物色素分析，定性恢复了近500a来程海湖泊初始生产力演化过程，结果表明，近500a来程海湖泊初始生产力总体上呈现由低到高的上升趋势，其中1700AD前后，1790AD前后是湖泊初始生产力出现变化的界限，另外，色素含量变化揭示研究时期内存在1750AD前后，1930AD前后二次明显暖波动。     

南海北部藻类粒级结构及色素成分对浮游植物吸收系数的影响

在珠江口、广东沿岸及南海北部三个航次生物-光学数据的基础上,研究了色素打包效应和色素成分的变化对浮游植物吸收系数的影响,结果表明,两种因素对吸收系数都有较大的贡献,但在不同的水体它们的影响程度各有不同.对网采浮游植物含量较高的珠江口和广东沿岸的水体而言,色素打包效应较强,对675 nm处比吸收系数的贡献平均分别为40%和20%;对微型浮游植物占主导地位的南海北部航次的水体,打包效应较弱,对675 nm处比吸收系数的影响平均仅为6%.采用多元线性回归的方法对吸收光谱进行分析,发现除叶绿素a之外的辅助色素对吸收系数的贡献主要表现在蓝绿光波段,三个航次440 nm波长处对总吸收的贡献平均分别为44%,43%和53%,其中对珠江口和广东沿岸航次的水体主要是光合类胡萝卜素的吸收贡献,而对南海北部航次的水体除了光合类胡萝卜素以外还要受到光保护类胡萝卜素的影响.由于河口、近岸和外海水体藻类粒级结构和辅助色素成分对浮游植物吸收系数的贡献有明显的差异,在南海北部水体建立比较精确的生物光学模型时,需考虑藻类粒级结构及色素成分对浮游植物吸收系数的影响.     

高效液相色谱法测量海洋浮游植物色素浓度

JGOFS计算和SeaWiFS计划推荐高效液相色谱（HPLC）作为海洋浮游植物色色浓度的测量方法。文章参考SeaWiFS计划制定的HPLC分析规范，叙述采用反相C18ODS色谱柱、996PDA、自动进样器（未配柱温箱）和三元梯度的色谱法测量海洋浮游植物色素浓度的具体实践。     

Palaeolimnological studies of the eutrophication of volcanic Lake Albano (Central Italy)

We use palaeolimnological techniques to reconstruct the eutrophication history of a volcanic lake (Lake Albano, central Italy) over the past three centuries. The presence of annual varves down to the bottom of the core (c. 1700 A.D.) indicated the lack of bioturbation and likely long-term meromixis. Sedimentation rates were estimated by varve counts (calcite/diatom couplets), indicating a mean rate of 0.15 cm yr^–1. The reconstruction of eutrophication was traced using past populations of algal and photosynthetic bacteria (through their fossil pigment), and geochemistry, as well as fossil remains of chironomids. Phaeophorbidea and the red carotenoid astaxanthin were used to detect past zooplankton development.The first sign of trophic change related to human activities is datedc. 1870 A.D. From that period onward a sharp increase of authigenic CaCO₃, nitrogen, N:P ratio, and dinoxanthin, a characteristic carotenoid of Chrysophyceae and Dinophyceae, is observed.Chironomid analyses showed the near absence of a deep water fauna throughout the core length. The populations of chironomid larvae are restricted to oxygenated littoral zones. In fact, the few fossil remains found are primarily of littoral origin, representing shallow water midges that were transported to profundal waters. The reduction of total chironomid in the uppermost layers of the core is to be related to human land uses.     

Seasonal and interannual variability of phytoplankton pigment in the Laccadive (Lakshadweep) Sea as observed by the Coastal Zone Color scanner

Based on Coastal Zone Color Scanner data from November 1978 through December 1981, the seasonal cycle of phytoplankton pigment in the upper part of the euphotic zone is established for the offshore Laccadive Sea. Year-round, the pigment content is low and the seasonal range is small, following the pattern of the nutrient-poor Arabian Sea to the west. Apparently, indigenous phytoplankton blooms are absent. July and August, however, were poorly studied because of cloud cover. Interannual differences during the northeast monsoon and the spring intermonsoon periods are minor. The abundant phytoplankton caused by the upwelling off India during the southwest monsoon remains essentially restricted to the shelf, but there are occasional large, zonal outbreaks into the Laccadive Sea, as well as others advected to the south of India. Visual inspection of the raw CZCS scenes for June through November 1982–1985, with almost no data until August or even September, shows such outbreaks of pigment-rich water to be common. Inspection of monthly SeaWiFS images for 1997 through part of 2001 confirms the absence of indigenous phytoplankton blooms.     

Isotopic Tracing of Trophication Processes over the Last Millennia on Lake Chenghai

Multi-parameter studies (stable isotopes in carbonate and organic matter, pigment,organic carbon and nitrogen contents) from a 660-yr continuous sediment core from Lake Cheng-hai, a closed, eutropic lake in southern China, provide information on lake historical eutrophi-cation. During the last 660 years, great changes have taken place in productivity and eutrophi-cation of Lake Chenghai in response to human activities. In 1690, the productivity of the lakebegan to increase as Lake Chenghai became closed from agriculture in the lake‘‘ s watershed. In 1942, Lake Chenghai evolved to eutrophic state, marked by an increase in organic carbon, ni-trogen, CaC03, pigment contents and obvious negative values of stable isotopes, which is more or less simultaneous with the large-scale population immigration during the period. In 1984, in-tensive human activities induced modern lacustrine productivity and eutrophic level. Human-in-duced trophic changes during the past few decades have affected the Lake Chenghai ecosystem tosuch an extent that it has never experienced before in the last 660 years.     

冬季海南岛五个海湾浮游植物光合色素分布的比较研究

为了研究海南岛周边海湾浮游植物群落分布特征,于2010年12月在海南岛周边5个海湾(海口湾、澄迈湾、洋浦-新英湾、陵水新村湾、三亚大东海)进行生态调查,分析了调查区域表层水的光合色素分布特征、浮游植物群落结构以及环境因素,对浮游植物不同类群的影响。本次调查共检出17种光合色素,岩藻黄素和叶绿素a是含量最高的两种色素,平均值分别达到0.410?g/L和0.278?g/L。CHEMTAX分析表明,调查海湾浮游植物类群主要包括硅藻、甲藻、蓝藻、青绿藻、隐藻等;浮游植物类群以硅藻为主,其次是隐藻与青绿藻。海南岛北部3个海湾(海口湾、澄迈湾、洋浦-新英湾)的硅藻比例低于南部2个海湾(陵水新村湾、三亚大东海),但其隐藻比例高于南部海湾。RDA结果显示,不同门类的浮游植物受环境因子影响的模式不同:定鞭藻、金藻、蓝藻与盐度、温度呈较强正相关,而与硅酸盐呈较强负相关;硅藻与盐度、温度呈较强正相关,与DIN、硅酸盐、磷酸盐呈负相关;甲藻、绿藻与DIN、磷酸盐呈较强正相关并与其他环境因子相关性较小;隐藻、青绿藻与硅酸盐呈较强正相关,与盐度、温度呈极强负相关。     

应用特征光合色素研究东海和南海北部浮游植物的群落结构

应用高效液相色谱并结合二极管阵列检测器分析技术，研究了东海与南海北部典型断面浮游植物的光合色素组成，进而由CHEMTAX软件估算浮游植物群落结构。结果表明：东海断面浮游植物叶绿素a生物量大于南海北部断面。受海水层化结构影响，东海PN断面浮游植物群落结构形成上层和下层两种类型，上层以蓝藻为主要优势类群；下层以硅藻为主要优势类群。南海北部S断面浮游植物群落形成近岸与离岸两种类型，近岸以硅藻、隐藻、绿藻为主要优势类群；离岸以定鞭金藻、蓝藻、原绿球藻为主要优势类群。初步分析了研究海区浮游植物群落结构与环境因子的关系。     

浅议浅黄色花岗岩板材在高温条件下变色因素

奇台县菊花黄花岗岩板材,经高温氧-乙炔喷焰烧后呈褐红色薄膜状石材板,使其经济价值增加80%.菊花黄花岗岩板材中的钾长石矿物经高温氧-乙炔喷焰烧后,当其受热达到一定的温度时褐黄色微斜长石中所含的低价铁氧化物中的2价铁离子变为3价铁离子,使岩石的颜色由黄色转化为褐红色,微斜长石由三斜晶系向稳定的单斜晶系转变,由于高于900℃高温作用石材表面时间短,故能在石材表面形成厚约1mm左右的红色薄膜.经褪色强化实验,从理论上推测该红色薄膜石材在大气条件下可保持10年以上不褪色.