Seasonal variations of particulate silicon in the Changjiang (Yangtze River) Estuary and its adjacent area

• Published in: Acta oceanologica Sinica Vol. 32; no. 4; pp. 1 - 10
• Main Authors: Cao, Lu, Liu, Sumei, Ren, Jingling
• Format: Journal Article
• Language: English
• Published: Heidelberg The Chinese Society of Oceanography 01.04.2013; Springer Nature B.V; Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China
• Subjects: Aquatic ecosystems; Biogeochemistry; Biomass; Blooms; Blooms (microorganisms); Brackish; Climatology; Coasts; Community policing; Diatoms; Dinoflagellates; Earth and Environmental Science; Earth Sciences; Ecology; Engineering Fluid Dynamics; Environmental Chemistry; Estuaries; Estuarine dynamics; Experiments; Marine; Marine & Freshwater Sciences; Nutrients; Oceanography; Offshore; Phosphorus; Phytoplankton; Plankton; Resuspension; Rivers; Seasonal variation; Seasonal variations; Seasons; Sedimentation rates; Silica; Silicon; Spatial distribution; Summer; Surface layers; Suspended particulate matter; Changjiang River; China; Yangtze River; INW, China, People's Rep., Changjiang Delta; China, People's Rep., Changjiang R; biogenic silica; Changjiang (Yangtze River) Estuary; East China Sea; dissolved silicate; suspended particulate matter; lithogenic silica
• ISSN: 0253-505X; 1869-1099
• DOI: 10.1007/s13131-013-0293-5

Temporal and spatial distribution of biogenic (BSi) and lithogenic (LSi) silica were studied in the Changjiang (Yangtze River) Estuary and its adjacent area. The annual average BSi and LSi concentrations were (1.71±1.79) µmol/L and (0.56±1.41) mmol/L, respectively. Both BSi and LSi were high in the inshore areas, where they received terrigenous discharge from the Changjiang, and decreased towards the offshore region. BSi and LSi were most abundant at the near bottom layer due to the high sedimentation rates and resuspension of sediment. Diatom blooms occurred in summer with high Chl a concentration in the surface layer, which induced that BSi in the surface layer during summer was obviously higher than that in the surface layer of other seasons. LSi concentration was maximal in autumn and spring and minimum in summer, associated with the seasonal variation of SPM values. Drifting investigation and mesocosm experiments were conducted during dinoflagellate bloom, aiming to understand the effect of nutrients on BSi by changing the phytoplankton composition. The results show that the low dissolved inorganic phosphorus concentration and high molar ratio of N/P (dissolved inorganic nitrogen vs. dissolved inorganic phosphorus), were the important factors for decreasing diatombiomass in the study area, and it would subsequently decrease the BSi concentration in aquatic ecosystem.