Open AccessThe nonconservative property of dissolved molybdenum in the western Taiwan Strait: Relevance of submarine groundwater discharges and biological utilization
Author(s) -
Wang Deli,
Xia Weiwei,
Lu Shuimiao,
Wang Guizhi,
Liu Qian,
Moore Willard S.,
Arthur Chen ChenTung
Publication year - 2016
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2014gc005708
Subject(s) - submarine groundwater discharge , sedimentary rock , seawater , groundwater , environmental chemistry , sedimentary organic matter , geology , scavenging , organic matter , dissolved organic carbon , water column , sulfide , adsorption , environmental science , oceanography , geochemistry , chemistry , aquifer , geotechnical engineering , biochemistry , organic chemistry , antioxidant
This study examined dissolved Mo and sedimentary Mo along with hydrochemical parameters in the western Taiwan Strait (WTS) in May and August 2012. The results demonstrate that dissolved Mo could be depleted of as high as 10–20 n M during our May sampling period when the nutrient‐enriched Min‐Zhe coastal current ceased and spring blooms developed. The negative correlation between Chl‐ a and dissolved Mo suggests the possible involvement of high algal productivity in removing dissolved Mo out of the water column. Specific oceanographic settings (little currents) permitted a high sedimentary enrichment of Mo (>6 µg/g Mo) within the highly productive waters outside the Jiulong River mouth. Possibly, the high algal productivities and consequent organic matter sinks provide a pathway of Mo burial from water columns into sediments. Dissolved Mo was relatively high in groundwater samples, but we observed that submarine groundwater discharges (SGDs) only contributed to a relatively small percentage of the total dissolved Mo pool in WTS. It is probably attributable to the immediate removal of SGD‐released Mo ions via adsorption onto newly formed Mn oxides once exposed to oxygenated seawater, followed by an elevated sedimentary Mo accumulation near the SGDs (∼5 µg/g). In addition to metal oxide particle scavenging and sulfide precipitation, we estimated that biological uptake along with Mo adsorption onto organic matter carriers could finally provide more than 10% of the annual sedimentary Mo accumulation in WTS.