摘要
红树林湿地是高效的滨海蓝色碳汇,在调节全球碳循环中发挥着重要的作用。本研究借助沉积物的粒度、总有机碳(TOC)与总氮(TN)的比值(TOC/TN)、有机碳同位素(δ^(13)C)和^(210)Pb年代学等相关参数,研究广西铁山港红树林湿地有机碳(OC)来源、沉积物沉积通量、OC埋藏通量的时间变化趋势。结果表明:沉积物粒度以粉砂、砂为主,TOC含量和δ^(13)C变化范围分别为0.26%~3.96%、-27.4‰~-21.4‰,TOC、TN、δ^(13)C具有较好的一致性。铁山港红树林湿地OC来源中陆源占35.0%,海源占30.5%,红树林源占34.5%。在100年来沉积物有机碳通量平均值为87.6 g/(m^(2)·a),0~50 cm区间的沉积物碳储量占沉积物柱中(95 cm)总储量的65.3%。自1961年以后,因水库大坝建设,沉积物沉积通量总体减小;1961-1999年间,由于气候及流域周围人类干扰等因素,导致更多陆源有机碳的输入和埋藏;1999-2020年,极端天气和自然因素下,红树林湿地遭破坏退化,从而降低了TOC含量及OC埋藏通量;2010年以来,沉积物中TOC含量增加,这可能与其含水量较高、凋落物累积和根系生长有关,OC来源以红树林源的贡献为主。
Mangrove wetlands are efficient coastal blue carbon sinks and play an important role in regulating the global carbon cycle.In this study,using grain size distribution,total organic carbon/total nitrogen(TOC/TN)ratio,δ^(13)C values,and^(210)Pb chronological parameter,we investigated the sources of organic carbon(OC)and the temporal trends in sediment deposition and OC burial fluxes in the mangrove wetland of Tieshangang Bay,Guangxi.The results indicated that the sediment grain size was dominated by silt and sand,with TOC content andδ^(13)C ranging from 0.26%to 3.96%and from−27.4‰to−21.4‰,respectively.There was a strong correlation between TOC,TN,andδ^(13)C values.The sedimentary organic matter in Tieshangang Bay had mainly a mixed signature with an average terrigenous contribution of 35.0%,marine sources 30.5%and mangrove contributions 34.5%,respectively.The average sediment OC flux over the past 100 years is 87.6 g/(m^(2)·a),and the carbon storage in sediments over the upper 50 cm can account for 65.3%of the total storage over the 95 cm depth.After 1961,there was a general decrease in sediment flux due to the construction of reservoir dams.Between 1961 and 1999,more terrestrial sources of OC were imported and buried due to climate and human disturbances around the watershed.Between 1999 and 2020,mangrove wetlands were destroyed and degraded due to extreme weather and natural factors.Degradation of mangrove wetlands under extreme weather and natural factors reduced the TOC content and OC burial fluxes.Since 2010,TOC content in the sediments has increased,probably due to higher water content,accumulation of litter and root growth.The OC source is dominated by the contribution from mangrove sources.
作者
杨奕昕
张芬芬
任旭
杜金秋
廖日权
杜金洲
Yang Yixin;Zhang Fenfen;Ren Xu;Du Jinqiu;Liao Riquan;Du Jinzhou(State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China;National Marine Environment Monitoring Centre,Dalian 116023,China;Pinglu Canal and Beibu Gulf Coastal Ecosystem Observation and Research Station of Guangxi,Guangxi Key Laboratory of Marine Environmental Change and Disaster in Beibu Gulf,College of Marine Sciences,Beibu Gulf University,Qinzhou 535011,China)
出处
《海洋学报》
北大核心
2025年第5期1-11,共11页
基金
国家重点研发计划(2022YFE0209300)
广西北部湾海洋环境变化与灾害研究重点实验室(北部湾大学)开放课题(2022KF003)。
关键词
红树林湿地
有机碳
沉积记录
来源与埋藏
铁山港
mangrove wetlands
organic carbon
sedimentary record
source and burial
Tieshangang Bay
