关键词: 生物扰动, 沉积物, 颤蚓, pH值, 溶解氧, 微电极

Abstract:

Tubificid was selected as the bioturbator. Highresolution distribution and variation of pH and dissolved oxygen (DO) in the microenvironment of sediment near the tubificids’ burrows were investigated by laboratory simulation experiments via microelectrodes. The results indicate that the pH value of sediment increased with time going at first, and then decreased. The bioturbation of tubificids had an inhibitory effect on this decrease of pH value. At the same bioturbation time, the surface pH value of the sediment around the tubificid burrows declined (up to 0.3 pH units). This effect of declining could become effective in an area of 1 mm radius around the burrows. Without tubificids, DO value level of the microenvironment near watersediment interface decreased with time going. In the presence of tubificids, the DO value level near the watersediment interface around the tubificid burrows increased (increased by 92—170 μmol/L) in the horizontal direction. The penetration depth of DO also increased, and the maximum penetration depth increased from 3 mm to 5 mm. Therefore, the presence of tubificids would affect the contaminants in the watersediment interface by changing the distribution and variation pattern of pH and DO of the sediment microenvironment.

Key words: bioturbation, sediment, tubificid, pH value, dissolved oxygen, microelectrode