东海赤潮高发区沉积物中叶绿素的分析

Sediment chlorophyll in HAB(Harmful Algal Bloom) area of East China Sea

研究分析了 2 0 0 2年 8～ 9月“赤潮 973”航次所采集的沉积物中叶绿素a及其降解产物脱镁叶绿酸含量与分布 .结果表明 ,叶绿素a和脱镁叶绿酸是同源的 ;随深度增加叶绿素a和脱镁叶绿酸的含量呈递减趋势 ,到一定深度后含量不再变化 ,个别站位叶绿素a和脱镁叶绿酸的垂直分布出现了许多小突跃 ,可能是由生物扰动引起 ;表层沉积物 (0～ 0 .5cm )中的叶绿素a和脱镁叶绿酸的变化幅度分别为 0 .14～1.17和 0 .83～ 5 .5 8μg·g-1,平均值分别为 0 .5 4和 2 .4 5 μg·g-1;并初步探讨水深 (光强 )、盐度、温度、含水量对叶绿素水平分布的影响 ;脱镁叶绿酸作为叶绿素的主要降解产物 ,到一定深度后 ,成为叶绿素的主要存在形式 ,约占 80 %～ 90 % ;由于水温的不同 ,夏季沉积物中的叶绿素a和脱镁叶绿酸含量是春季的 3倍之多 ;比较了上层水柱中的叶绿素和沉积物中的叶绿素的相对含量 ,平均而言 ,沉积物中叶绿素占上层水柱中叶绿素的 31% .

The content and distribution of chlorophyll a (chl-a) and phaeopigments (pha-a) in the sediment of East China Sea was investigated in August and September ,2002.The results showed that chlorophyll a and phaeopigments had the same resource.Both chlorophyll a and phaeopigments decreased significantly with increasing depth, and would be stable to a certain depth.There are several observed leaps in the vertical distribution of chlorophyll a and phaeopigments,which might reflect the effects of bioturbation.The chlorophyll a and phaeopigments concentration on the surface of sediment varied from 0.14 to 1.17 μg·g -1 and 0.83 to 5.58 μg·g -1, respectively,and the mean concentrations in the top centimeter of sediment (0～0.5cm) were 0.54μg·g -1 for chlorophyll a and 2.45μg·g -1 for phaeopigments.The spatial distribution of benthic chlorophyll a and phaeopigments were affected by the combination of several factors such as depth (and therefore light) ,temperature, salinity and water content.As the main degradation product of chlorophyll a, phaeopigments became the main type of chlorophyll while increased to certain extent,and acounting for 80～90% of total chlorophyll.Due to the water temperature ,the surface chlorophyll a and phaeopigments concentration varied significantly with the season.Total chlorophyll a in the sediment accounted for 31% of total chlorophyll a in the water column.