Distribution and Sources of Organic Matter in Surface Sediments of the Karachi Coast,Pakistan  

作　　者：KAHKASHAN Sanober LI Zhongqiao JALALI Bassem WANG Xinhong INAM Asif SALEEM Monawwar AFTAB Javed JI Zhongqiang BAI Youcheng RAN Lihua LI Hongliang CHEN Jianfang 

机构地区：[1]Key Laboratory of Marine Ecosystem Dynamics,Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China [2]State Key Laboratory of Marine Environmental Science,College of the Environment and Ecology,Xiamen University,Xiamen 361005,China [3]National Institute of Oceanography,Clifton,Block-1,Karachi,Pakistan [4]Bahria School of Maritime and Applied Sciences,Bahria University Karachi Campus,Karachi,Pakistan [5]Observation and Research Station of Yangtze River Delta Marine Ecosystems,Ministry of Natural Resources,Zhoushan 361000,China [6]Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519000,China [7]State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310061,China

出　　处：《Journal of Ocean University of China》2024年第6期1561-1571,共11页中国海洋大学学报（英文版）

基　　金：funded in part by the Ocean Negative Carbon Emissions(ONCE)Program,the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(No.SL2023MS019);the Scientific Research Fund of the Second Institute of Oceanography(No.JB2404);the National Natural Science Foundation of China(Nos.U23A2034,42076242,41941013,42176039,41906045);the Global Change and Air-Sea Interaction II Program(Nos.GASI-04-HYST-06,GASI-04-HYST-01);the Zhejiang Provincial Natural Science Foundation of China(No.LDT23D06023D06);the China Government Marine Scholarship。

摘　　要：Under the steadily intensifying human activities in coastal areas,it is crucial to distinguish the sources of organic matter(OM)in sediments for better understanding of the environmental change.In this study,25 surface sediments collected along the harbor and creeks areas off Karachi coast were used for total organic carbon(TOC),total nitrogen(TN),stable carbon(δ^(13)C)and nitrogen(δ^(15)N)isotopic compositions,phytoplankton biomarkers(brassicasterol,dinosterol and cholesterol)and glycerol dialkyl glycerol tetraethers(GDGTs)analyses,to trace the distribution of OM and identify its sources.TOC,TN,δ^(13)C,and δ^(15)N are in the range of 0.04% to 5.28%,0.01% to 0.57%,-17.55‰ to -26.31‰,and 2.83‰ to 6.04‰,respectively.C/N values range from 4.24 to 21.04.The δ^(13)C,δ^(15)N,C/N,BIT(Branched Isoprenoid Tetraether)index together with phytoplankton biomarkers show both marine and terrestrial OM input to the creeks and Harbor stations.In contrast,the stations from Western Coast indicate a marine source predominance.A clearly impact of human activities is seen from sediments near river mouths.

关 键 词：surface sediments organic matter stable carbon and nitrogen isotopes biomarkers Karachi coast 

分 类 号：P736.41[天文地球—海洋地质]