山东荣成天鹅湖大叶藻形态和生长的季节性变化研究

Seasonal variations in the morphology and growth of Zostera marina in Swan Lake, Shandong

2012年8月至2013年7月,作者逐月对天鹅湖大叶藻(Zostera marina L.)的形态特征、植株密度、生物量和生产力进行了监测。结果表明,大叶藻周年株高最高值和最低值分别出现在7月和1月;叶鞘高度、叶鞘宽度和叶宽的最高值均出现在7月,叶鞘高度最低值出现在1月,叶鞘宽度和叶宽最低值均出现在2月;大叶藻顶枝、侧枝和花枝的周年密度最大值分别出现在6月、4月和5月,最小值分别出现在1月、8月和7月;单株生物量和地上部分生物量最大值均出现在7月,地下部分出现在10月,而单株生物量和地上部分生物量最小值均出现在1月,地下部分生物量最小值出现在3月;单株地上和地下生产力最大值均出现在6月,最小值则分别出现在1月和2月。分析显示,大叶藻在冬季由于水温较低导致生长缓慢,且植株较小,在春季随水温上升,生长开始加快。水温在夏初达到大叶藻的最适生长水温,大叶藻的生物量和初级生产力达到最高值,而夏末和初秋由于水温过高导致大叶藻个体生物量、密度和初级生产力开始降低。这种季节性变化与水温的季节性变化密切相关。

The morphological characteristics, density, biomass and productivity of Zostera marina L. in Swan Lake were monitored monthly from August 2012 to July 2013. The results showed that the highest and lowest values of shoot height were observed in July and January, respectively. The highest values of sheath height, sheath and leaf width were all observed in July, and the lowest value of sheath height in January, and the lowest values of sheath and leaf width were all observed in February. The highest values of terminal, lateral and flowering shoot density were observed in June, April and May, respectively, and the lowest values were observed in January, August and July, respectively. The highest values of shoot biomass and above-ground biomass of eelgrass all appeared in July, and the highest value of below-ground biomass appeared in October, while the lowest values of shoot and above-ground biomass all appeared in January, and the lowest value of below-ground biomass appeared in March. The highest values of shoot above- and below-ground productivity were all observed in June, and the lowest value in January and February, respectively. Statistics showed that eelgrass grew slowly and was small in winter as a result of low temperature, and the growth accelerated with temperature rising in spring. The water temperature in early summer was optimal for eelgrass growth, and as a result, the biomass and productivity reached the maximum values. While the biomass, shoot density and productivity of eelgrass began to decrease in late summer and early autumn because of the extremely hight water temperature. These seasonal variations were strongly correlated with seasonally varied water temperature.