基于探索性数据分析的大型海藻重金属富集特征

大型海藻对海水中的重金属有较强的吸附作用，是重金属污染的理想指示生物。2017年6月，在枸杞岛海藻场采集到19种大型海藻优势种，使用ICP-MS检测7种重金属（Cu、Zn、Cr、Cd、Pb、As和Hg）的含量，结果表明，不同海藻的重金属含量存在显著差异，平均含量顺序为:Zn > As > Cr > Cu > Hg > Pb > Cd。重金属在不同海藻门类中的含量也存在差异，Cu、Cd和As在褐藻中含量较高，红藻中Zn、Cr含量较高，而绿藻中Hg和Pb含量较高。与国内其他海域相比，除Cu、Hg偏高外，枸杞岛海域海藻中其他重金属含量处于中低水平。采用聚类分析的方法，将19种大型海藻分为6类，同一种重金属的富集水平可分为3类。重金属含量相关性分析表明，Cd和As、Pb和Hg之间存在极显著相关，Cu和Pb、Zn和Pb之间存在显著相关。本文通过主成分分析计算可以得出，多管藻类对重金属的综合富集能力最强。

Characteristics of heavy metal enrichment in macroalgae based on exploratory data analysis

Macroalgae present a high capacity to absorb heavy metals in seawater, which is an ideal indicator of heavy metal pollution. Nineteen dominant species of macroalgae were collected from the seaweed farm of Gouqi Island in June 2017, and the contents of seven kinds of heavy metals (Cu, Zn, Cr, Cd, Pb, As and Hg) were determined using inductively coupled plasma source mass spectrometer, The average content order was: Zn > As > Cr > Cu > Hg > Pb > Cd. The contents of heavy metals in different phyla also varied, with higher contents of Cu, Cd and As in brown algae, higher contents of Zn and Cr in red algae, and higher contents of Hg and Pb in green algae. Compared with other sea areas in China, except for higher levels of Cu and Hg, other heavy metals contents in the Gouqi Island's macroalgae are at a medium or low level. Cluster analysis was performed on nineteen species of macroalgae, they could be divided into 6 categories, and the enrichment level of the each heavy metal could be divided into 3 categories. The results of correlation analysis suggested that there existed a significant correlation between Cu and Pb, Zn and Pb, and there existed an extremely significant correlation between Cd and As, Pb and Hg. The principal component analysis indicated that the Polysiphonia senticulosa showed the strongest comprehensive enrichment ability.