As speciation distribution in ornithogenic sediments from the Ross Sea region,East Antarctica

• 作 者: ChuangnengLou[1]XiaodongLiu[1]WenqiLiu[2]LibinWu[1]YaguangNie[1]
• 机 构: Institute of Polar Environment,School of Earth and Space Sciences,University of Science and Technolo
• 出 处: 2015中国极地科学学术年会
• 发表日期: 2015年期

　　Ornithogenic sediments are rich in toxic As(arsenic)compounds,posing a potential threat to local ecosystems.Here we analyzed the distribution of As speciation in three ornithogenic sediment profiles MB6,BI and CC.The distributions of total As and total P(phosphorus)concentrations were highly consistent in all three profiles,indicating that guano input is a major factor controlling total As distribution in the ornithogenic sediments.The As found in MB6 and CC is principally As(Ⅴ)(arsenate),in BI As(Ⅲ)(arsenite)predominates,but the As in fresh guano is largely composed of DMA(dimethylarsinate).The significant difference of As species between fresh guano and ornithogenic sediment samples may be related to diagenetic processes affecting the guano after deposition by seabirds.The distributions of As(Ⅲ)/As(Ⅴ)and chlorophyll a in the MB6 and BI profiles are highly consistent,demonstrating that the biotransformation of aquatic algae may be an important factor determining the distribution patterns of As speciation.Based on the analysis of oxidation-reduction conditions in studied sediments,these patterns are also influenced by the sedimentary environment.