Distribution, seasonality, and fluxes of dissolved organic matter in the Pearl River (Zhujiang) estuary, China

doi:10.5194/bg-16-2751-2019

CORC > 南海海洋研究所 > 中国科学院南海海洋研究所 > 热带海洋环境国家重点实验室(LTO)

	Distribution, seasonality, and fluxes of dissolved organic matter in the Pearl River (Zhujiang) estuary, China
	Li, Ruihuan 2; Li, Yang ; Song, Guisheng 4; Massicotte, Philippe 3; Yang, Fangming 4; Xie, Huixiang 1
刊名	BIOGEOSCIENCES
	2019
卷号	16 期号:13 页码:2751
ISSN号	1726-4170
DOI	10.5194/bg-16-2751-2019
英文摘要	Dissolved organic carbon (DOC) concentration in the Pearl River estuary (PRE) of China was measured in May, August, and October 2015 and January 2016. Chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) in the latter three seasons were characterized by absorption and fluorescence spectroscopy. CDOM and FDOM exhibited negligible seasonal variations, while DOC displayed a significant seasonality, with the average concentration being highest in May (156 mu mol L-1), lowest in November (87 mu mol L-1), and comparable between January (118 mu mol L-1) and August (112 mu mol L-1). Although DOC, CDOM, and FDOM in surface water were generally higher than in bottom water, the difference between the two layers was statistically insignificant. DOC showed little crossestuary variations in all seasons, while CDOM and FDOM in January were higher on the west side of the estuary than on the east side. All three variables showed rapid drawdowns in the head region of the estuary (salinity < 5); their dynamics in the main estuary were primarily controlled by conservative mixing, leading to linearly declining or relatively constant (for DOC in May and November only) contents with increasing salinity. The decrease in FDOM with salinity was 5 %-35% faster than that of CDOM, which in turn was 2-3 times quicker than that of DOC. Salinity and CDOM absorption coefficients could serve as indicators of DOC in August and January. Freshwater endmembers in all seasons mainly contained fresh, protein-rich DOM of microbial origin, a large part of it likely being pollution-derived. Protein-like materials were preferentially consumed in the head region but the dominance of the protein signature was maintained throughout the estuary. Exports of DOC and CDOM (in terms of the absorption coefficient at 330 nm) into the South China Sea were estimated as 195 x 10(9) g and 266 x 10(9) m(2) for the PRE and 362 x 10(9) g and 493 x 10(9) m(2) for the entire Pearl River Delta. The PRE presents the lowest concentrations and export fluxes of DOC and CDOM among the world's major estuaries. DOM delivered from the PRE is, however, protein-rich and thus may enhance heterotrophs in the adjacent coastal waters. Overall, the PRE manifests lower abundance and smaller spatiotemporal variability of DOM than expected for a sizable estuary with a marked seasonality of river runoff due supposedly to the poorly forested watershed of the Pearl River, the rapid degradation of the pollutionderived DOM in the upper reach, and the short residence time of freshwater.
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/17701]
专题	南海海洋研究所_热带海洋环境国家重点实验室(LTO)
作者单位	1.Chinese Acad Sci, South China Sea Inst Oceanol, State Key Lab Trop Oceanog, Guangzhou 510301, Guangdong, Peoples R China 2.Univ Laval, Takuvik Joint Int Lab UMI 3376 Univ Laval Canada, Quebec City, PQ G1V 0A6, Canada 3.Tianjin Univ, Sch Marine Sci & Technol, Tianjin 300072, Peoples R China 4.Tianjin Univ Sci & Technol, Coll Marine & Environm Sci, Tianjin 300457, Peoples R China 5.Univ Quebec, Inst Sci Mer Rimouski, Rimouski, PQ G5L 3A1, Canada
推荐引用方式 GB/T 7714	Li, Ruihuan,Li, Yang,Song, Guisheng,et al. Distribution, seasonality, and fluxes of dissolved organic matter in the Pearl River (Zhujiang) estuary, China[J]. BIOGEOSCIENCES,2019,16(13):2751, 2770.
APA	Li, Ruihuan,Li, Yang,Song, Guisheng,Massicotte, Philippe,Yang, Fangming,&Xie, Huixiang.(2019).Distribution, seasonality, and fluxes of dissolved organic matter in the Pearl River (Zhujiang) estuary, China.BIOGEOSCIENCES,16(13),2751.
MLA	Li, Ruihuan,et al."Distribution, seasonality, and fluxes of dissolved organic matter in the Pearl River (Zhujiang) estuary, China".BIOGEOSCIENCES 16.13(2019):2751.