Open AccessRelationships between optical backscattering, particulate organic carbon, and phytoplankton carbon in the oligotrophic South China Sea basin
Author(s) -
Guoqiang Qiu,
Xiaogang Xing,
Emmanuel Boss,
XiaoHai Yan,
Rui Ren,
Wei Xiao,
Haili Wang
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.422671
Subject(s) - phytoplankton , biogeochemical cycle , oceanography , total organic carbon , ocean color , environmental science , particulates , water column , environmental chemistry , nutrient , ecology , biology , geology , chemistry , physics , satellite , astronomy
The particulate backscattering coefficient (b bp ) provides effective proxies for particulate organic carbon (POC) and phytoplankton carbon (C phy ); however, their bio-optical relationships in the oligotrophic ocean are rarely reported. In this work, based on the in-situ synchronous optical and biogeochemical measurements in the oligotrophic South China Sea (SCS) basin, we refined the regional relationships between POC (and C phy ) and b bp and investigated the impacts of phytoplankton community compositions and size classes on the b bp variability. The observations showed that: 1) POC and C phy exhibited good linear relationships with b bp ; 2) the relationship between C phy and POC could also be fitted in a linear function with a positive POC intercept, and the POC contributed by phytoplankton-covarying non-algal particles was nearly two-fold of C phy ; and 3) the POC-specific b bp (b* bp ) was positively correlated with the fraction of the phytoplankton groups haptophytes (Type 8) and diatoms to total Chla, but negatively correlated with the fraction of pico-phytoplankton to Chla (f pico ). These findings suggest that in oligotrophic waters, the variability of b* bp was mainly determined by the variability in the relative contribution of large phytoplankton with complex structures.