The isotopic composition of Cadmium in the water column of the South China Sea

Yang, Shun‐Chung; Lee, Der-Chuen; Ho, Tung‐Yuan

doi:10.1016/j.gca.2012.09.022

Cited by 57 publications

(46 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The increase in Cd : P ratios to the north of the SAZ can be explained by the depletion of Cd at P , 0.9 mmol L 21 , which prevented further preferential removal of Cd with respect to P. On the other hand, the increase in Cd : P ratios to the south can be explained by upwelling of high Cd : P deep waters, consistent with high preferential Cd particle incorporation in the surface Southern Ocean and remineralization at intermediate depth. Incorporation of Cd into particles is principally through biological uptake as adsorption to biogenic matter is considered to be minor based on previous studies in mesocosms (Kremling et al 1978;Kuiper 1981) and the open ocean (Yang et al 2012), although a study in the English Channel suggested that Cd adsorption to bacterial surfaces may be important during phytoplankton blooms (Dixon et al 2006).…”

Section: Discussionmentioning

confidence: 99%

Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate

Baars¹,

Abouchami²,

Galer³

et al. 2014

Limnology & Oceanography

109

View full text Add to dashboard Cite

We report isotope dilution analyses of dissolved cadmium (Cd) and electrochemical Cd speciation measurements in the Atlantic sector of the Southern Ocean. Bioavailable inorganic Cd is . 100 times higher in nearsurface waters south of the Polar Front compared to the Subantarctic Zone because of upwelling and reduced complexation by organic Cd ligands. To trace local changes in the relation between Cd and P, we examine the deviations from a linear deep-water Cd vs. P relation (Cd*), and find that changes in Cd* coincide with the position of frontal systems and covary with primary productivity and total dissolved Mn and Fe concentrations. These covariations agree with potential local changes in phytoplankton Cd uptake rates, resulting from differences in the availability of Cd, Zn, Mn, and Fe. A band of negative Cd* values is associated with formation of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW). In contrast to SAMW, which may export low Cd : P ratios from the Southern Ocean, the Cd : P ratios in AAIW increase by mixing with underlying Upper Circumpolar Deep Water before being exported from the Southern Ocean. Deep waters show constant Cd : P ratios, and both elements behave conservatively with end-member mixing between deep waters of the Weddell Gyre, the Antarctic Circumpolar Current, and inflowing North Atlantic Deep Water. Overall, our results support the hypothesis that the kink in the global Cd vs. P relation is largely caused by high Cd : P uptake ratios in the trace-nutrient-limited Southern Ocean.

show abstract

Section: Discussionmentioning

confidence: 99%

Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate

Baars¹,

Abouchami²,

Galer³

et al. 2014

Limnology & Oceanography

109

View full text Add to dashboard Cite

show abstract

“…It further confirms that the longest

{R e T}_{\max}

as a function of depth mainly occurs in the intermediate layer, since it takes approximately 38 years for 90% of the intermediate water to be refreshed, whereas the time needed for the same to happen in the lower layer is much shorter (∼33 years). Unlike what previous studies have proposed [e.g., Yang et al ., ], that

{R e T}_{\max}

increases monotonically with depth, this longest

{R e T}_{\max}

in the intermediate layer suggests that the formation of intermediate water is deferred, under the prevailing anti‐cyclonic circulation (Figure b).…”

Section: Intrinsic Characteristics Of Water Pathways In the Scsmentioning

confidence: 99%

“…Yang et al . [] is the only study that notes an increment in

R e T

with depth. They proposed that it takes ∼48 years to form the intermediate and lower layers (850–3500 m), and that the

R e T

of the surface water is approximately 1.3 years.…”

Section: Introductionmentioning

confidence: 99%

“…In this sense, the waters at different locations/depths of a vast basin, like SCS in this research, are controlled by the time‐dependent, three‐dimensional circulation, and have varying pathway and

R e T

. With the complex nature of the circulation, the residence time of water mass cannot be well presented by a flushing time, computed by dividing the volume of the basin with the exchanging flow along its boundary [e.g., Yang et al ., ]. It has long been realized that deep water is prone to be refreshed in the region/layer where cyclonic circulation prevails [ Gascard , ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Three‐dimensional pathways of water masses in the South China Sea: A modeling study

Liu

Gan

2017

JGR Oceans

View full text Add to dashboard Cite

We conduct a numerical Eulerian analysis on the Lagrangian characteristics of South China Sea (SCS) water masses. This is the first study to investigate the water pathway and residence time in response to time‐dependent, three‐dimensional basin circulation in the SCS. The circulation of the SCS is largely determined by westward intrusions of the northwestern Pacific waters in the upper layer (0–750 m) and deep layer (>1500 m), and by an eastward extrusion in the intermediate layer (750–1500 m) through Luzon Strait (LS). The waters in these three layers are interlinked to sustain the three‐dimensional circulation in the SCS. The upper intrusive waters flow cyclonically and have a residence time of ∼3 years before they subduct into a deeper layer or exit the SCS through surrounding straits. The intrusive denser waters in the deep layer flow along the northern slope and reside for ∼25 years in the northern basin (north of 13°N), where a strong subduction occurs. A cyclonic circulation exists in the deep layer in the southern basin (south of 13°N), where a subduction of intermediate waters occurs over its eastern side and a deep upwelling exists over its western side. The water in the deep southern basin has a residence time of ∼40 years. The upwelled deep waters and the subducted waters from the upper layer form the intermediate water, where waters circulate anti‐cyclonically toward LS and have a longest residence time (∼42 years). These findings are supported by the spatial variation in the observed potential density variance.

show abstract

“…In the surface ocean above 200 m, δ 114 Cd increases to even heavier values (+3‰) as Cd concentrations become very depleted due to biological uptake within the euphotic zone.Here, biological incorporation of light Cd into phytoplankton leaves the residual dissolved Cd pool isotopically heavy, with the very heavy δ 114 Cd surface values consistent with previously reported values of +3 to +5‰ for similar low concentration surface waters in the Pacific and AtlanticConway and John, 2015).The overall pattern in Cd and δ 114 Cd reflects what is known about dissolved Cd and δ 114 Cd in the oceans, namely that both are controlled by large-scale water mass circulation and influenced by biological activity in surface waters (e.gRipperger et al, 2006;Abouchami et al, 2014). A range of studies from different oceans now show δ 114 Cd to be fairly homogenous (+0.2 to +0.3‰) in deep waters with Cd concentrations of 0.4-1 nmol kg -1 from the Pacific, Southern and Atlantic Oceans and the South China SeaBoyle et al, 2012;Xue et al, 2012;Yang et al, 2012;Conway et al, 2013;Abouchami et al, 2014). We represent this deep-water δ 114 Cd value as a purple dashed line inFig.…”

mentioning

confidence: 99%

The cycling of iron, zinc and cadmium in the North East Pacific Ocean – Insights from stable isotopes

Conway

John

2015

Geochimica et Cosmochimica Acta

152

133

View full text Add to dashboard Cite

The isotopic composition of Cadmium in the water column of the South China Sea

Cited by 57 publications

References 29 publications

Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate

Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate

Three‐dimensional pathways of water masses in the South China Sea: A modeling study

The cycling of iron, zinc and cadmium in the North East Pacific Ocean – Insights from stable isotopes

Contact Info

Product

Resources

About