Dissolved concentrations and organic speciation of copper in the Amazon River estuary and mixing plume

Hollister, Adrienne Patricia; Whitby, Hannah; Seidel, Michael; Lodeiro, Pablo; Gledhill, Martha; Koschinsky, Andrea

doi:10.1016/j.marchem.2021.104005

Cited by 16 publications

(19 citation statements)

References 98 publications

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“…DOC concentrations ( Fig. 2D ) agreed with those reported in the region ( 29 ) and showed some evidence of removal in the inner estuary and inputs close to the mangrove forests [see also ( 30 )], but the considerable changes in chlorophyll a in the estuarine plume did not appear to have a marked impact on the DOC concentrations.…”

Section: Resultssupporting

confidence: 85%

“…We concentrated DOM and elements (S SPE-amb , P SPE-amb , Fe SPE-amb , Al SPE-amb , Cu SPE-amb , Zn SPE-amb , Ni SPE-amb , Co SPE-amb , and Mn SPE-amb ) using SPE at ambient pH to minimize potential changes in extracted TM SPE-amb stoichiometry that could arise from sample acidification, which is typically used to improve DOM recoveries ( 40 ). We found a relatively constant but low recovery of 8 ± 2% for C SPE-amb ( n = 22) in our extracts ( 30 ), which is comparable to recoveries obtained using SPE at pH 8 in other studies ( 6 , 41 ). We calculated the total concentrations of elements concentrated from the sum of all peaks detected in each chromatographic mode, SEC ( Fig.…”

Section: Resultssupporting

confidence: 85%

“…2C ; S = 27.6), but this was rapidly depleted in an offshore direction by phytoplankton productivity. Sediments associated with mangrove forests have been identified as a source of dissolved organic carbon (DOC) ( 30 , 38 ), inorganic C ( 39 ), and TMs ( 30 , 31 ) to coastal waters in this region. DOC concentrations ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…We compared TM SPE-amb with dissolved TM concentrations by assuming that the 8% recovery observed for C SPE-amb ( 30 ) was also representative for the TM SPE-amb pool ( Fig. 4 ).…”

Section: Resultsmentioning

confidence: 99%

“…The Amazon estuary forms a conduit for the largest river on Earth in terms of discharge volume and creates an estuarine plume that can be traced to the center of the Atlantic Ocean ( 27 ). The estuarine plume is unusual in that the high flux of fresh water (100,200 to 240,000 m 3 s −1 ) ( 28 ) pushes the estuary onto the continental shelf, delivering DOM ( 29 ) and TMs ( 30 – 32 ) to coastal and offshore waters. The plume thus constitutes a source of nutrients ( 28 ) and essential TMs such as Fe, Mn, and Co to the equatorial Atlantic Ocean ( 33 , 34 ).…”

Section: Introductionmentioning

confidence: 99%

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Trace metal stoichiometry of dissolved organic matter in the Amazon plume

et al. 2022

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Dissolved organic matter (DOM) is a distinct component of Earth’s hydrosphere and provides a link between the biogeochemical cycles of carbon, nutrients, and trace metals (TMs). Binding of TMs to DOM is thought to result in a TM pool with DOM-like biogeochemistry. Here, we determined elemental stoichiometries of aluminum, iron, copper, nickel, zinc, cobalt, and manganese associated with a fraction of the DOM pool isolated by solid-phase extraction at ambient pH (DOM SPE-amb ) from the Amazon plume. We found that the rank order of TM stoichiometry within the DOM SPE-amb fraction was underpinned by the chemical periodicity of the TM. Furthermore, the removal of the TM SPE-amb pool at low salinity was related to the chemical hardness of the TM ion. Thus, the biogeochemistry of TMs bound to the DOM SPE-amb component in the Amazon plume was determined by the chemical nature of the TM and not by that of the DOM SPE-amb .

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Section: Resultssupporting

confidence: 85%

Section: Resultssupporting

confidence: 85%

Section: Resultsmentioning

confidence: 99%

“…We compared TM SPE-amb with dissolved TM concentrations by assuming that the 8% recovery observed for C SPE-amb ( 30 ) was also representative for the TM SPE-amb pool ( Fig. 4 ).…”

Section: Resultsmentioning

confidence: 99%