南极典型海域浮游生物生产力/群落结构对BP/MCP储碳影响及其年代际变率  

Effects of plankton productivity/community structure on BP/MCP carbon storage and their interdecadal variations in a typical Antarctic waters

作　　者：杨丹 付全有 韩正兵 于培松 乐凤凤 韩喜彬 张海生 卢冰 武光海 Yang Dan;Fu Quanyou;Han Zhengbing;Yu Peisong;Le Fengfeng;Han Xibin;Zhang Haisheng;Lu Bing;Wu Guanghai(Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China;Key Laboratory of Marine Ecosystem Dynamics,Ministry of Natural Resources,Hangzhou 310012,China;Key Laboratory of Submarine Geosciences,Ministry of Natural Resources,Hangzhou 310012,China)

机构地区：[1]自然资源部第二海洋研究所,浙江杭州310012 [2]自然资源部海洋生态系统动力学重点实验室,浙江杭州310012 [3]自然资源部海底科学重点实验室,浙江杭州310012

出　　处：《海洋学报》2024年第5期37-56,共20页

基　　金：国家自然科学面上基金项目(42076243,41976227)。

摘　　要：利用南极半岛(D1-7)和南奥克尼群岛附近海域(D5-6)海洋沉积物有机质的分子生物标志物中所隐含的生态学关系,将重建的浮游生物生产力和种群结构变化与生物泵(BP)/微型生物碳泵(MCP)以及海洋碳汇和储碳效率联系起来研究。柱样沉积物中的一系列分子生物标志物在近百年里发生显著变化,上层海洋浮游生物生产力/群落结构与沉积碳库储量存在较大的时空演变,实际上均与全球气候变化相联系。研究结果如下:(1)从生物标志化合物正构烷烃分子组合特征和色谱图峰型、主峰碳(MH)、轻烃/重烃(L/H)、菌藻类-(nC_(15)+nC_(17)+nC_(19))、大型浮游植物-(nC_(21)+nC_(23)+nC_(25))和碳优势指数-(CPI)来看,沉积碳源主要是海源生物碳,海洋生物是固碳与储碳的天然碳汇。(2)D5-6柱样的有机质高富集,主要受海洋上层水体较高初级生产力、高沉积速率(平均为0.19 cm/a)、水深较浅(385 m)和还原性沉积环境(Pr/Ph值平均为0.95)这些均有利于颗粒有机碳(POC)通过BP过程从海洋表面输送到深海,快速埋藏和储存;而D1-7柱样因水深大(1 100 m)和沉积速率低(0.07 cm/a),含碳化合物沉降过程中发生降解,又被环境氧化降解(Pr/Ph值平均为1.22),二者均不利于沉积物储碳,但相比之下控制沉积物碳保存重要的因素可能是沉积速率。(3)近百年来南极半岛附近海域和南奥克尼群岛浮游动物总量、浮游植物初级生产力、硅藻和甲藻生物量趋于上升,而颗石藻生物量和所占比例呈减少趋势(南极半岛附近海域更明显),说明钙质生物泵作用在逐年下降,而硅藻主导的硅质泵作用在不断加强,这两个过程的相对强度在很大程度上决定了由生物泵结构(硅质泵/钙质泵)和效率、及其向海洋沉积物输送有机碳和无机碳的比例大小。(4)2个柱样的分子生物标志物变化趋势在整体上具有一定的可比性,均有明显的阶段性,在年代际突变后(19Utilizing the molecular biomarkers of organic matter in marine sediments from the Antarctic Peninsula(D1-7) and adjacent waters of the South Orkney Islands(D5-6),the ecological relationships implicit in the reconstructed variations of planktonic productivity and population structure are examined in relation to the Biological Pump(BP)/Microbial Carbon Pump(MCP),as well as the efficiency of marine carbon sinks and storage.Over the past century,a series of molecular biomarkers in sediment cores has exhibited significant changes,reflecting substantial spatiotemporal evolution in upper ocean planktonic productivity/community structure and sedimentary carbon reservoirs.These changes are indeed linked to global climate variability.The research findings are as follows:(1) Based on the characteristics of molecular composition and chromatographic peak patterns of biomarker compounds,as well as parameters such as Main Peak Carbon(MH),Light Hydrocarbons/Heavy Hydrocarbons(L/H),Bacterial-Algal Ratio(nC_(15) + nC_(17) + nC_(19)),Large Phytoplankton Ratio(nC_(21) + nC_(23 )+ nC_(25)),and carbon preference index(CPI),it is evident that the primary source of sedimentary carbon is marine-derived organic carbon.Marine organisms serve as natural carbon sinks for carbon fixation and storage.(2) The sediments from the D5-6 region exhibit high organic matter enrichment,primarily influenced by factors such as higher surface water productivity,higher sedimentation rates(average of 0.19 cm/a),shallower water depths(385 m),and a reducing sedimentary environment(average Pr/Ph value of 0.95).These conditions favor the transport of Particulate Organic Carbon(POC)from the ocean surface to the deep sea via the Biological Pump(BP) process,facilitating rapid burial and storage.In contrast,sediments from the D1-7 region,characterized by greater water depths(1 100 m) and lower sedimentation rates(0.07 cm/a,experience degradation of carbonaceous compounds during sedimentation processes and subsequent oxidative degradation in an oxic environment(aver

关 键 词：南极半岛和南奥克尼群岛 浮游生物生产力/群落结构 生物泵和微型生物碳泵 分子生物标志物 微生物细胞膜GDGTs 年代际变率 

分 类 号：P714.5[天文地球—海洋科学]