Mangrove forest degradation indicated by mangrove-derived organic matter in the Qinzhou Bay,Guangxi,China,and its response to the Asian monsoon during the Holocene climatic optimum  

作　　者：MENG Xianwei XIA Peng LI Zhen LIU Lejun 

机构地区：[1]First Institute of Oceanography,State Oceanic Administration [2]Laboratory for Marine Geology and Environment,Qingdao National Laboratory for Marine Science and Technology [3]State Key Laboratory of Estuarine and Coastal Research,East China Normal University

出　　处：《Acta Oceanologica Sinica》2016年第2期95-100,共6页海洋学报（英文版）

基　　金：The National Basic Research Program (973 Program) of China under contract No.2010CB951203;the National Natural Science Foundation of China under contract Nos 41376075,41576061 and 41206057

摘　　要：The response of mangrove ecosystems to the Asian monsoon in the future global warming can be understood by reconstructing the development of mangrove forests during the Holocene climatic optimum（HCO）, using proxies preserved in coastal sediments. The total organic matter in sediments of a segmented core, with calibrated age ranges between 5.6 and 7.7 cal. ka BP and corresponding to the HCO, from the Qinzhou Bay in Guangxi, China, is quantitatively partitioned into three end-members according to their sources： mangrove-derived, terrigenous,and marine phytoplanktonic, using a three-end-member model depicted by organic carbon isotope（δ13Corg） and the molar ratio of total organic carbon to total nitrogen（C/N）. The percentage of mangrove-derived organic matter（MOM） contribution is used as a proxy for mangrove development. Three visible drops in MOM contribution occurred at ca. 7.3, ca. 6.9, and ca. 6.2 cal. ka BP, respectively, are recognized against a relatively stable and higher MOM contribution level, indicating that three distinct mangrove forest degradations occurred in the Qinzhou Bay during the HCO. The three mangrove forest degradations approximately correspond to the time of the strengthened/weakened Asian winter/summer monsoon. This indicates that even during a period favorable for the mangrove development, such as the HCO, climatic extremes, such as cold and dry events driven by the strengthened/weakened Asian winter/summer monsoon, can trigger the degradation of mangrove forests.The response of mangrove ecosystems to the Asian monsoon in the future global warming can be understood by reconstructing the development of mangrove forests during the Holocene climatic optimum（HCO）, using proxies preserved in coastal sediments. The total organic matter in sediments of a segmented core, with calibrated age ranges between 5.6 and 7.7 cal. ka BP and corresponding to the HCO, from the Qinzhou Bay in Guangxi, China, is quantitatively partitioned into three end-members according to their sources： mangrove-derived, terrigenous,and marine phytoplanktonic, using a three-end-member model depicted by organic carbon isotope（δ13Corg） and the molar ratio of total organic carbon to total nitrogen（C/N）. The percentage of mangrove-derived organic matter（MOM） contribution is used as a proxy for mangrove development. Three visible drops in MOM contribution occurred at ca. 7.3, ca. 6.9, and ca. 6.2 cal. ka BP, respectively, are recognized against a relatively stable and higher MOM contribution level, indicating that three distinct mangrove forest degradations occurred in the Qinzhou Bay during the HCO. The three mangrove forest degradations approximately correspond to the time of the strengthened/weakened Asian winter/summer monsoon. This indicates that even during a period favorable for the mangrove development, such as the HCO, climatic extremes, such as cold and dry events driven by the strengthened/weakened Asian winter/summer monsoon, can trigger the degradation of mangrove forests.

关 键 词：Holocene climatic optimum mangrove-derived organic matter degradation of mangrove forests Asian monsoon Qinzhou Bay 

分 类 号：S718.5[农业科学—林学]