Journal Article

The biogenic silica composition, behavior and budget in the Changjiang Estuary

RAN Xiangbin;LIU Jun;LIU Sen;ZANG Jiaye;WANG Baodong;ZHAO Jun

2018

Overview

Three comprehensive surveys were performed in the Changjiang（Yangtze River） Estuary（CJE） to understand the biogenic silica（BSi） composition, behavior and budget. It is indicated that the BSi is composed of phytoliths,phytoplankton and sponges; phytolith BSi has 16 forms and account for 23% to 83% of the bulk BSi in the maximum turbidity zone. The budget shows that the major exogenous BSi source in the water column of the CJE is the riverine input, accounting for 95% of the total BSi input. Dominant processes that maintain BSi levels in the water column are the primary production（55 Gmol/a） and the subsequent BSi sedimentation（46 Gmol/a）; and the BSi pool produced by the primary production represents two point three times the BSi loading of the Changjiang River and 63% of the BSi output, respectively. The net export（26 Gmol/a） of BSi from the CJE to the East China Sea and Yellow Sea roughly equals the riverine BSi loading. The observed total accumulation of BSi is one point seven times larger than the loading of total BSi output, with 53% to 88% of phytolith BSi and their assemblage, indicating that there has already been a ＂filter＂ of terrestrial BSi. The reverse weathering in sediments is an important process for the reactive silica removal in the CJE due to authigenic alterations. It is indicated that the phytolith fluxes in the suspended load represent a significant BSi source in the estuary, and the CJE would act as a net BSi sink.

• Publisher: The Chinese Society of Oceanography,Springer Nature B.V,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China%Marine Ecology Research Center, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China%Key Laboratory of Marine Ecosystem and Biogeochemistry, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China,Marine Ecology Research Center, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
• Subject: Budgeting / Budgets / Climatology / Composition / Earth and Environmental Science / Earth Sciences / Ecology / Engineering Fluid Dynamics / Environmental Chemistry / Estuaries / Estuarine dynamics / Fluxes / Marine & Freshwater Sciences / Oceanography / Phytoplankton / Primary production / Removal / Rivers / Sedimentation / Sediments / Silica / Silicon dioxide / Surveys / Suspended load / Turbidity / Water circulation / Water column / Weathering