摘要
溶解有机氮(DON)作为近海生态系统总溶解态氮(TDN)的重要赋存形态,其生物可利用性对查明绿潮爆发期间氮的供给机制具有重要意义。本文通过2015年在青岛近海浒苔(Ulva prolifera)绿潮爆发期间和消亡后两个航次调查,对比分析了该海域绿潮爆发期和消亡后溶解有机碳(DOC)、TDN、溶解无机氮(DIN)、DON及其中具有高生物可利用性组分尿素、总溶解态氨基酸(TDAA)浓度变化,以TDAA在DOC中碳摩尔比[TDAA(%DOC)]为指标,评价该海域绿潮爆发期和消亡后DON的生物可利用性。绿潮爆发期青岛近海氮浓度受陆源输入影响较绿潮消亡期明显,不同形态氮的浓度高于绿潮消亡期,DON浓度均值为(13.84±6.77)μmol·L^(-1),较绿潮消亡后高44.5%,在TDN中占比均达到(56.8±9.3)%。其中,尿素和TDAA合计占DON的(38.5±6.4)%。受浮游植物分泌和细菌降解等生物作用调控,DON生物可利用性呈现由表层到底层逐步降低的变化特征;而绿潮爆发期浒苔分泌较多新鲜的DON,导致其生物可利用性高于消亡后。DON在微生物作用下快速转化为DIN并为浒苔所吸收是绿潮爆发期间氮供给的主要机制之一。
Dissolved organic nitrogen(DON)typically comprises the majority of the total dissolved nitrogen(TDN)in coastal waters.In order to understand the supply mechanisms of nitrogen for maintaining the outbreak of Ulva prolifera,it is significance to accurately evaluate the bioavailability of DON in the coastal waters.In this study,two cruises were conducted during and after Ulva prolifera green bloom(GB)in 2015 in Qingdao coastal waters(QDC),variations of the concentrations of dissolved organic carbon(DOC),TDN,dissolved organic nitrogen(DIN)and DON as well as urea and total dissolved amino acid(TDAA),which have been recognized the components with high bioavailabilty in DON pool,were investigated.The carbon-normalized yield of total dissolved amino acids[TDAA(%DOC)]was used to indicate DON bioavailability during and after the GB.Concentrations of different forms of nitrogen during GB were significantly higher than after GB in QDC due to terrigenous input.During the outbreak of GB,the average concentration of DON was(13.84±6.77)μmol·L-1,which was 44.5%higher than that after GB,and accounted for(56.8±9.3)%of TDN.The sum of urea and TDAA concentration accounted for(38.5±6.4)%of DON.Under influence of phytoplankton secretion and bacteria biodegradation,the bioavailability of DON decreased from surface to bottom water layer in the QDC.Because of the strong ability of U.prolifera to secret fresh and reactive DON during the GB,the bioavailability of DON during the GB was higher than that after the GB.During the GB,the fast conversion of considerable amount of DON to DIN,which is easy to absorbed by U.prolifera,was identified as another important source and supply of nitrogen for maintaining GB in QDC.
作者
修彬
梁生康
李小姣
葛瑶
房旭东
霍韵汐
郭金强
王云飞
XIU Bin;LIANG Sheng-Kang;LI Xiao-Jiao;GE Yao;FANG Xu-Dong;HUO Yun-Xi;GUO Jin-Qiang;WANG Yun-Fei(Key Laboratory of Marine Chemistry Theory and Technology,Ministry of Education,Ocean University of China,Qingdao 266100,China;College of Chemistry and Chemical Engineering,Ocean University of China,Qingdao 266100,China)
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第10期37-46,共10页
Periodical of Ocean University of China
基金
国家海洋局公益性课题项目(201205018)
中央高校基本科研业务费专项项目(201762032)资助~~
关键词
青岛近海
浒苔
溶解有机氮
氨基酸
生物可利用
Qingdao coastal areas
Ulva prolifera
dissolved organic nitrogen
amino acids
bioavailability
作者简介
修彬(1991-),男,硕士,主要从事近海氮生物地球化学循环研究。E-mail:xiu1179519596@foxmail.com;通讯作者:梁生康,-mail:liangsk@ouc.edu.cn。
