Mangrove degradation must reduce carbon sequestration in recent years, thereby aggravating global warming.Thus, short-term impacts of human activity on mangrove ecosystems are cause for concern from local governments ...Mangrove degradation must reduce carbon sequestration in recent years, thereby aggravating global warming.Thus, short-term impacts of human activity on mangrove ecosystems are cause for concern from local governments and scientists. Mangroves sediments can provide detailed records of mangrove species variation in the last one hundred years, based on detailed 210 Pb data. The study traced the history of mangrove development and its response to environmental change over the last 140 years in two mangrove swamps of Guangxi, Southwest China. Average sedimentation rates were calculated to be 0.48 cm/a and 0.56 cm/a in the Yingluo Bay and the Maowei Sea, respectively. Chemical indicators（δ13Corg and C：N） were utilized to trace the contribution of mangrove-derived organic matter（MOM） using a ternary mixing model. Simultaneous use of mangrove pollen can help to supplement some of these limitations in diagenetic/overlap of isotopic signatures. We found that vertical distribution of MOM was consistent with mangrove pollen, which could provide similar information for tracing mangrove ecosystems. Therefore, mangrove development was reconstructed and divided into three stages： flourishing, degradation and re-flourishing/re-degradation period. The significant degradation, found in the period of 1968–1998 and 1907–2007 in the Yingluo Bay and the Maowei Sea, respectively, corresponding to a rapid increase of reclamation area and seawall length, rather than climate change as recorded in the region.展开更多
Located between terrestrial and marine ecosystems,mangrove forests are sensitive to changes in climate.The responses of mangrove ecosystems to climate change in the future can be understood by reconstructing past mang...Located between terrestrial and marine ecosystems,mangrove forests are sensitive to changes in climate.The responses of mangrove ecosystems to climate change in the future can be understood by reconstructing past mangrove dynamics using proxies preserved in the intertidal sediments.Considering the complexity of the proxies commonly used,it is necessary to develop a relatively simple,inexpensive proxy.In this study,available chemical tracers(δ13Corg and C:N)of the four cores(YLW02,YLW03,O18,and Q37)from the intertidal zone of the northern Beibu Gulf(NBG)and a three-end-member(mangrove,sea grass,and suspended particulate matter)model was utilized to determine the contribution of mangrove-derived organic matter(CMOM)in carbonate-free sediments.Compared with the summed concentration of mangrove pollen(SCMP),a significant positive correlation between CMOM and SCMP is displayed.The calculated CMOM for an additional 210Pb-dated sediment core from the Yingluo Bay,NBG(YLW01)clearly indicates a mangrove development going through degradation,flourishing,relative degradation,and relative flourishing,which are separately in correspondence with the lowest,highest,lower,and higher air temperature and rainfall in the time intervals of 1890–1918 AD,1919–1956 AD,1957–1990 AD,and 1991–2010 AD.This suggests that CMOM preserved in intertidal sediments has a potential to reconstruct historical mangrove development in high resolution,at the very least,along the coasts of the NBG.展开更多
Mangroves can not only provide multiple ecosystem service functions,but are also efficient carbon producers,capturers,and sinks.The estimation of the organic carbon accumulation rate(OCAR)in mangrove sediments is fund...Mangroves can not only provide multiple ecosystem service functions,but are also efficient carbon producers,capturers,and sinks.The estimation of the organic carbon accumulation rate(OCAR)in mangrove sediments is fundamental for elucidating the role of mangroves in the global carbon budget.In particular,understanding the past changes in the OCAR in mangrove sediments is vital for predicting the future role of mangroves in the rapidly changing environment.In this study,three dated sediment cores from interior and fringe of mangroves in the Yingluo Bay,China,were used to reconstruct the spatiotemporal variations of the calculated OCAR since 1900 in this area.The increasing OCAR in the mangrove interior was attributed to mangrove flourishment induced by climate change characterized by the rising temperature.However,in the mangrove fringe,the strengthening hydrodynamic conditions under the sea level rise were responsible for the decreasing OCAR,particularly after the1940 s.Furthermore,the duration of inundation by seawater was the primary factors controlling the spatial variability of the OCAR from the mangrove fringe to interior,while the strengthened hydrodynamic conditions after the 1940 s broke this original pattern.展开更多
基金The National Basic Research Program(973 Program)of China under contract No.2010CB951203the National Natural Science Foundation of China under contract Nos 41206057,41576067,41376075 and 41576061
文摘Mangrove degradation must reduce carbon sequestration in recent years, thereby aggravating global warming.Thus, short-term impacts of human activity on mangrove ecosystems are cause for concern from local governments and scientists. Mangroves sediments can provide detailed records of mangrove species variation in the last one hundred years, based on detailed 210 Pb data. The study traced the history of mangrove development and its response to environmental change over the last 140 years in two mangrove swamps of Guangxi, Southwest China. Average sedimentation rates were calculated to be 0.48 cm/a and 0.56 cm/a in the Yingluo Bay and the Maowei Sea, respectively. Chemical indicators（δ13Corg and C：N） were utilized to trace the contribution of mangrove-derived organic matter（MOM） using a ternary mixing model. Simultaneous use of mangrove pollen can help to supplement some of these limitations in diagenetic/overlap of isotopic signatures. We found that vertical distribution of MOM was consistent with mangrove pollen, which could provide similar information for tracing mangrove ecosystems. Therefore, mangrove development was reconstructed and divided into three stages： flourishing, degradation and re-flourishing/re-degradation period. The significant degradation, found in the period of 1968–1998 and 1907–2007 in the Yingluo Bay and the Maowei Sea, respectively, corresponding to a rapid increase of reclamation area and seawall length, rather than climate change as recorded in the region.
基金The National Natural Science Foundation of China under contract No.41576061the Basic Scientific Fund for National Public Research Institutes of China under contract No.2017Q03
文摘Located between terrestrial and marine ecosystems,mangrove forests are sensitive to changes in climate.The responses of mangrove ecosystems to climate change in the future can be understood by reconstructing past mangrove dynamics using proxies preserved in the intertidal sediments.Considering the complexity of the proxies commonly used,it is necessary to develop a relatively simple,inexpensive proxy.In this study,available chemical tracers(δ13Corg and C:N)of the four cores(YLW02,YLW03,O18,and Q37)from the intertidal zone of the northern Beibu Gulf(NBG)and a three-end-member(mangrove,sea grass,and suspended particulate matter)model was utilized to determine the contribution of mangrove-derived organic matter(CMOM)in carbonate-free sediments.Compared with the summed concentration of mangrove pollen(SCMP),a significant positive correlation between CMOM and SCMP is displayed.The calculated CMOM for an additional 210Pb-dated sediment core from the Yingluo Bay,NBG(YLW01)clearly indicates a mangrove development going through degradation,flourishing,relative degradation,and relative flourishing,which are separately in correspondence with the lowest,highest,lower,and higher air temperature and rainfall in the time intervals of 1890–1918 AD,1919–1956 AD,1957–1990 AD,and 1991–2010 AD.This suggests that CMOM preserved in intertidal sediments has a potential to reconstruct historical mangrove development in high resolution,at the very least,along the coasts of the NBG.
基金The National Natural Science Foundation of China under contract Nos 41976068 and 41576061。
文摘Mangroves can not only provide multiple ecosystem service functions,but are also efficient carbon producers,capturers,and sinks.The estimation of the organic carbon accumulation rate(OCAR)in mangrove sediments is fundamental for elucidating the role of mangroves in the global carbon budget.In particular,understanding the past changes in the OCAR in mangrove sediments is vital for predicting the future role of mangroves in the rapidly changing environment.In this study,three dated sediment cores from interior and fringe of mangroves in the Yingluo Bay,China,were used to reconstruct the spatiotemporal variations of the calculated OCAR since 1900 in this area.The increasing OCAR in the mangrove interior was attributed to mangrove flourishment induced by climate change characterized by the rising temperature.However,in the mangrove fringe,the strengthening hydrodynamic conditions under the sea level rise were responsible for the decreasing OCAR,particularly after the1940 s.Furthermore,the duration of inundation by seawater was the primary factors controlling the spatial variability of the OCAR from the mangrove fringe to interior,while the strengthened hydrodynamic conditions after the 1940 s broke this original pattern.
