脱镁叶绿素对浮游植物吸收特性的影响

THE EFFECTS OF PHEOPHYTIN ON ABSORPTION CHARACTERISTICS OF PHYTOPLANKTON

根据2007年6月期间对大连湾的调查数据,分析了脱镁叶绿素对浮游植物吸收特性的影响。由实测数据及相关文献推断出脱镁叶绿素蓝光和红光吸收峰分别位于412和670nm波段,并采用多元线性回归对脱镁叶绿素和叶绿素a的比吸收系数进行研究。结果表明,412nm波段脱镁叶绿素的比吸收系数远大于叶绿素a;440nm波段,叶绿素a的比吸收系数略大于脱镁叶绿素;670、675nm波段,叶绿素a的比吸收系数约为脱镁叶绿素的3倍。随脱镁叶绿素占色素总浓度比例的增大,浮游植物吸收曲线上蓝光吸收峰偏离440nm波段,逐渐向412nm波段靠近,并得到蓝光波段吸收峰的高度由脱镁叶绿素浓度决定,而红光波段吸收峰的高度由叶绿素a浓度决定。色素浓度与吸收系数进行乘幂函数拟合分析表明,412、440nm波段吸收系数与脱镁叶绿素浓度拟合相关性高于叶绿素a,而675nm波段相反。

The survey data obtained in the Dalian Bay, June 2007 were studied for the relationship between pheophytin and phytoplankton absorption. This and previous studies have shown that pheophytin absorption peaks appears at 412nm in the violet region of spectrum, and 670nm in the red. The multivariate linear regression analysis on specific absorption coefficients for pheophytin and chlorophyll a indicates that the specific absorption coefficients for pheophytin was much larger than chlorophyll a at 412nm; slightly larger than pheophytin at 440nm; and about 3 times larger than pheophytin at 670nm and 675nm. While the proportion of pheophytin in total pigment concentration increased, the absorption peak in the blue region of spectrum deviated from 440nm to near 412nm. The absorption peak height in the blue region was mainly influenced by pheophytin concentration, whereas the height in the red was decided more by chlorophyll a concentration. Fitting analysis with a power function for the pigment concentration and absorption coefficient showed that the absorption coefficients at 412nm and 440nm exhibited higher correlation with pheophytin concentration than chlorophyll a, but contrary at 675nm.