Adaption of Ulva pertusa to multiple-contamination of heavy metals and nutrients: Biological mechanism of outbreak of Ulva sp. green tide

The multiple-contamination of heavy metals and nutrients worsens increasingly and Ulva sp. green tide occurs almost simultaneously. To reveal the biological mechanism for outbreak of the green tide, Ulva pertusa was exposed to seven-day-multiple-contamination. The relation between pH variation (VpH), Chl a content, ratio of (Chl a content)/(Chl b content) (Rchla/chlb), SOD activity of U. pertusa (ASOD) and contamination concentration is VpH=1.72±0.38+1.68±0.72×10−4×Cammonia2 (p < 0.05), Cchla = 0.88± 0.09 − 0.01± 0.00 × CCd (p < 0.05), Rchla/chlb=0.72±0.04−0.35±0.08×10−4×CCd2 (p < 0.05), and ASOD=25.64±2.35−0.41±0.09×10−2×CZn2+0.54±0.10×CZn (p < 0.05), respectively. Cammonia, CCd and CZn is concentration of ammonia, Cd2 + and Zn2 +, respectively. Comparing the contamination concentrations of seawaters where Ulva sp. green tide occurred and the contamination concentrations set in the present work, U. pertusa can adapt to multiple-contaminations in these waters. Thus, the adaption to multiple-contamination may be one biological mechanism for the outbreak of Ulva sp. green tide.