Relationship between nutrients and plankton biomass in the turbidity maximum zone of the Pearl River Estuary
Zhen Shi , Jie Xu , Xiaoping Huang , Xia Zhang , Zhijian Jiang , Feng Ye , Ximei Liang
DOI:10.1016/j.jes.2016.11.013
Received March 23, 2016,Revised November 11, 2016, Accepted November 23, 2016, Available online December 21, 2016
Volume 29,2017,Pages 72-84
Nutrients, dissolved and particulate organic carbon and plankton (bacterio-, phyto- and zoo-) were compared in the turbidity maximum zone (TMZ) and adjacent areas (non-TMZ) in the Pearl River estuary. Our results showed that high levels of suspended substances had marked effect on dynamicsofnutrientsandplanktonintheTMZ.Based ontheclusteranalysisoftotal suspended solids (TSS) concentrations, all stations were divided into two groups, TMZ with average TSS of 171 mg/L and non-TMZ of 45 mg/L. Suspended substances adsorbed PO 43? and dissolved organic carbon,resulting inhigherparticulate phosphorusand organic carbon(POC)and lower PO 43?and DOC in the TMZ, compared to the non-TMZ. However, suspended substances had limited effect on nitrogenous nutrients. Phytoplankton growth was light-limited due to high concentrations of suspended substances in the TMZ and a peak of phytoplankton abundance appeared in the non-TMZ. In contrast, the highest bacterial abundance occurred in the TMZ, which was likely partly responsible for low DOC levels. Two peaks of zooplankton abundanceobserved inthe TMZ and non-TMZ in the Pearl River estuary were primarily supported by bacteria and phytoplankton, respectively. Our finding implied
that high levels of suspended solids in the TMZ affect the trophic balance.
