基于浮游植物吸收系数和光合有效辐射的南海区域性分粒级初级生产力算法初探  

A study of the regional size-fractionated primary production algorithm based on phytoplankton absorption coefficient and photosynthetically active radiation in the South China Sea

作　　者：赵红五一 周雯[1,3] 曾凯 邓霖 廖健祖 曹文熙 ZHAO Hongwuyi;ZHOU Wen;ZENG Kai;DENG Lin;LIAO Jianzu;CAO Wenxi(State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China;School of Marine Sciences,Sun Yat-sen University,Guangzhou 519082,China;School of Chemistry and Environmental Sciences,Guangdong Ocean University,Zhanjiang 524088,China)

机构地区：[1]中国科学院南海海洋研究所,热带海洋学国家重点实验室,广东广州510301 [2]中国科学院大学地球与行星科学学院,北京100049 [3]南方海洋科学与工程广东省实验室(广州),广东广州511458 [4]中山大学海洋科学学院,广东广州510275 [5]广东海洋大学化学与环境学院,广东湛江524088

出　　处：《热带海洋学报》2023年第1期43-55,共13页Journal of Tropical Oceanography

基　　金：南方海洋科学与工程广东省实验室(广州)重大专项创新团队项目(GML2019ZD0305、GML2019ZD0602);国家自然科学基金(41976170、41976172、42276181、41976181)。

摘　　要：海洋初级生产过程是海洋碳循环的重要组成部分,影响生物地球化学循环和全球气候变化。浮游植物作为海洋初级生产的主要贡献者,按粒径大小可分为小型(micro粒级,>20μm)、微型(nano粒级,2~20μm)和微微型(pico粒级,<2μm)。不同粒级浮游植物初级生产力(size-fractionated primary production,PP_(size))对总初级生产力贡献不同,在海洋物质能量流动及碳循环中扮演着不同角色。本文基于2019年南海西部夏季航次12个站位的生物光学剖面数据,研究了南海西部分粒级浮游植物叶绿素a浓度和初级生产力的空间分布及它们对总叶绿素a浓度和总初级生产力的贡献百分比。利用各粒级670nm波段的浮游植物吸收系数[size-fractionated phytoplankton absorption coefficient at 670nm,a_(ph-size)(670)]与光合有效辐射(photosynthetically active radiation,PAR)的乘积[a_(ph-size)(670)×PAR]建立了南海分粒级初级生产力算法,对于小型、微型和微微型浮游植物数据集,log[a_(ph-size)(670)×PAR]与log(PP_(size))之间的决定系数R^(2)分别为0.64、0.76和0.67。交叉验证的结果表明,该算法具有良好的泛化性能。其性能显著优于仅利用浮游植物吸收系数估算分粒级初级生产力的算法,表明PAR是影响分粒级初级生产力变化的重要因素之一。采用基于叶绿素a浓度的算法估算各粒级初级生产力时,针对小型和微微型浮游植物数据集,该算法的性能与本文构建的算法近似;但针对微型浮游植物数据集时,基于叶绿素a浓度的算法性能显著较低,这可能归因于微型浮游植物吸收系数与叶绿素a浓度间的弱相关性。Marine primary production is an important part of the ocean carbon cycle,affecting biogeochemical cycles and global climate change.Phytoplankton,as the main contributor to marine primary production,can be classified as micro-(>20μm),nano-(2~20μm),and pico-(<2μm)phytoplankton depending on particle size.Different phytoplankton size classes contribute differently to primary production(PP_(size))and thus play different roles in the oceanic circulation of matter or energy and ocean carbon cycle.Based on the bio-optical dataset collected at 12 stations in the western South China Sea in 2019,this study presented the spatial variability of size-fractionated primary production and chlorophyll a concentration of phytoplankton and their percentage contribution.The size-fractionated primary productivity of phytoplankton was well estimated from the product of size-fractionated phytoplankton absorption coefficient at 670nm[aph-size(670)]and photosynthetically active radiation(PAR)[a_(ph-size)(670)×PAR].The coefficients of determination R^(2)between log[aph-size(670)×PAR]and log(PP_(size))were 0.64,0.76,and 0.67 for the micro-,nano-,and picophytoplankton dataset,respectively.The cross-validation of the algorithm based on the size-fractionated phytoplankton absorption coefficient and PAR has shown a good generalization performance.This algorithm could better predict the size-fractionated primary productivity compared to the size-fractionated phytoplankton absorption coefficient as the only input.This result indicates that PARis one of the important factors to estimate the size-fractionated primary productivity.Meanwhile,the performance of the chlorophyll a concentration-based algorithm for estimating primary productivity at each size was closer to that of the algorithm constructed in this paper for both micro-and pico-phytoplankton dataset,but significantly lower for the nano-phytoplankton,probably due to the weak correlation between the absorption coefficients and chlorophyll a concentration of nano-phytoplankton.

关 键 词：分粒级浮游植物吸收系数 分粒级浮游植物初级生产力 光合有效辐射 分粒级叶绿素a 

分 类 号：P735.531[天文地球—海洋生物学]