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Role of colloids in upper ocean biogeochemistry in the northeast Pacific Ocean elucidated from ²³⁸U-²³⁴Th disequilibria

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Field Value
Title Role of colloids in upper ocean biogeochemistry in the northeast Pacific Ocean elucidated from ²³⁸U-²³⁴Th disequilibria
Names Huh, Chih-An (creator)
Prahl, Fredrick (creator)
Date Issued 1995 (iso8601)
Abstract Detailed upper ocean profiles of 234Th in dissolved (< 10,000 Daltons), colloidal (10,000 Da–O.45 μm),
and particulate (>0.45 μm) forms were measured at a station (46º45′N, 126ºW) in the northeast Pacific
Ocean. On average, dissolved, colloidal, and particulate 234Th accounted for ~78, 12, and 10% of the total
234Th in the cuphotic zone (()–100 m). A highly positive correlation exists between colloidal 234Th and
chlorophyll a; both are characterized by higher concentrations in surface waters, a subsurface maximum at
55 m in the seasonal thermocline, and undetectable levels below the euphotic zone. POC : Chl α ratios in
the water column suggest phytoplankton as primary producers of the colloidal material. Scavenging residence
times of dissolved, colloidal, and particulate 234Th with respect to their removal processes in the euphotic
zone are ~50, 6, and 8 d. The scavenging rate constant of Th apparently increases with the concentration
of colloids.
Genre Article
Identifier Huh, C., & Prahl, F. G. (1995). Role of colloids in upper ocean biogeochemistry in the northeast Pacific Ocean elucidated from ²³⁸U-²³⁴Th disequilibria. Limnology and oceanography, 43(3), 528-532.

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