菲律宾蛤仔的生物扰动对沉积物颗粒垂直分布的影响

The Effect of Bioturbation of Ruditapes philippinarum on the Vertical Distribution of Sedimert Particles

以化学稳定的荧光砂作为示踪颗粒 ,研究底栖双壳类软体动物菲律宾蛤仔对沉积物的扰动 ,探讨滤食性贝类通过生物扰动作用在水层—底栖耦合过程中的作用。实验表明 ,在整个实验周期 ( 15天 )内 ,表层示踪砂有 2 8.2 %悬浮进入水体 ,3 6.1%由表层垂直向下迁移 ,垂直迁移率为 1.65× 10 -5·g-1·cm-2 ·d-1;沉积物 8cm深处示踪砂分别有 2 7.0 %向上和12 .6%向下迁移 ,迁移率分别为 1.5 2× 10 -5·g-1·cm-2 ·d-1和 0 .61× 10 -5·g-1·cm-2 ·d-1。个体大小和摄食状态均对蛤仔的扰动作用有影响 :个体增大 ,表层示踪砂悬浮进入水体的量增加 ,以单位湿重表示的迁移率降低 ,但均无显著性差异 ;投饵组大于无饵组 ,除 8cm深处小蛤的垂直上移率外 ,其它无显著性差异。

The effect of bioturbation of Manila clam Ruditapes philippinarum on the vertical distribution of sediment particles was studied with tracer beads. The results of a fifteen day bioturbation expeninent showed that 28.2% of the tracer beads on the surface were suspended into overlying sea water, and 36.1% of the tracer beads were transferred downward with a vertical transportation rate of 1.65×10 -5 g -1 ·cm -2 ·d -1 . For tracer beads at 8cm depth, 27.0% were transferred upwards and 12.6% downwards with respectively the transportion rates of 1.52×10 -5 g -1 ·cm -2 ·d -1 and 0.61×10 -5 g -1 ·cm -2 ·d -1 .The size and diet both had an effect on the bioturbation of Manila clam: the percentage of tracer beads suspended into water increased and the transportation rate defined by unit weight decreased as the size increased howevre, no obvious difference was observed. The values of parameters in groups with food were all higher than groups without food, but the difference was not obvious except the upward transportation rate of small clam at 8cm depth.