Phytoplankton community composition, carbon sequestration, and associated regulatory mechanisms in a floodplain lake system

Junjie Jia; Yang Gao; Kun Sun; Yao Lu; Jing Wang; Kun Shi

doi:10.1016/j.envpol.2022.119411

Phytoplankton community composition, carbon sequestration, and associated regulatory mechanisms in a floodplain lake system

Environ Pollut. 2022 Aug 1:306:119411. doi: 10.1016/j.envpol.2022.119411. Epub 2022 May 4.

Authors

Junjie Jia¹, Yang Gao², Kun Sun³, Yao Lu¹, Jing Wang³, Kun Shi⁴

Affiliations

¹ Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, PR China.
² Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, PR China. Electronic address: gaoyang@igsnrr.ac.cn.
³ Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, PR China.
⁴ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China.

PMID: 35525519
DOI: 10.1016/j.envpol.2022.119411

Abstract

Phytoplankton contribute approximately 50% to the global photosynthetic carbon (C) fixation. However, our understanding of the corresponding C sequestration capacity and driving mechanisms associated with each individual phytoplankton taxonomic group is limited. Particularly in the hydrologically dynamic system with highly complex surface hydrological processes (floodplain lake systems). Through investigating seasonal monitoring data in a typical floodplain lake system and estimation of primary productivity of each phytoplankton taxonomic group individually using novel equations, this study proposed a phytoplankton C fixation model. Results showed that dominant phytoplankton communities had a higher gross carbon sequestration potential (CSP) (9.50 ± 5.06 Gg C each stage) and gross primary productivity (GPP) (65.46 ± 25.32 mg C m^-2 d^-1), but a lower net CSP (-1.04 ± 0.79 Gg C each stage) and net primary productivity (NPP) (-5.62 ± 4.93 mg C m^-3 d^-1) than rare phytoplankton communities in a floodplain lake system. Phytoplanktonic GPP was high (317.94 ± 73.28 mg C m^-2 d^-1) during the rainy season and low (63.02 ± 9.65 mg C m^-2 d^-1) during the dry season. However, their NPP reached the highest during the rising-water stage and the lowest during the receding-water stage. Findings also revealed that during the rainy season, high water levels (p = 0.56**) and temperatures (p = 0.37*) as well as strong solar radiation (p = 0.36*) will increase photosynthesis and accelerate metabolism and respiration of dominant phytoplankton communities, then affect primary productivity and CSP. Additionally, water level fluctuations drive changes in nutrients (p = -0.57*) and metals (p = -0.68*) concentrations, resulting in excessive nutrients and metals slowing down phytoplankton growth and reducing GPP. Compared with the static water lake system, the floodplain lake system with a lower net CSP became a heterotrophic C source.

Keywords: Carbon cycle; Carbon sequestration potential; Floodplain lake; Phytoplankton community; Primary productivity.

MeSH terms

Carbon
Carbon Sequestration
Lakes*
Phytoplankton*
Seasons
Water

Substances

Water
Carbon