FN Archimer Export Format
PT J
TI Copper-binding ligands in the NE Pacific
BT 
AF WHITBY, Hannah
   POSACKA, Anna M.
   MALDONADO, Maria T.
   VAN DEN BERG, Constant M. G.
AS 1:1;2:2;3:2;4:3;
FF 1:;2:;3:;4:;
C1 LEMAR, Technopole Brest Iroise, F-29280 Plouzane, France.
   Univ British Columbia, Vancouver, BC V6T 1Z4, Canada.
   Univ Liverpool, Liverpool L69 3GP, Merseyside, England.
C2 UBO, FRANCE
   UNIV BRITISH COLUMBIA, CANADA
   UNIV LIVERPOOL, UK
UM LEMAR
IF 2.713
TC 47
UR https://archimer.ifremer.fr/doc/00616/72780/72176.pdf
   https://archimer.ifremer.fr/doc/00616/72780/72177.jpg
   https://archimer.ifremer.fr/doc/00616/72780/72178.jpg
   https://archimer.ifremer.fr/doc/00616/72780/72179.jpg
   https://archimer.ifremer.fr/doc/00616/72780/72180.jpg
   https://archimer.ifremer.fr/doc/00616/72780/72181.jpg
   https://archimer.ifremer.fr/doc/00616/72780/72182.jpg
   https://archimer.ifremer.fr/doc/00616/72780/72183.pdf
LA English
DT Article
DE ;Copper speciation;Seawater;Thiols;Humic substances;Cathodic stripping voltammetry;Thiourea;Glutathione;Organic ligands
AB Copper distribution and speciation were determined at stations P4 and P26 along Line P as part of a GEOTRACES Process Study in the Northeast Pacific, at depths between 10 and 1400 m. Two ligand classes (L-1 and L-2) were detected at both stations: the stronger L-1 ligand pool with log K'(cu2+)(L1) 15.0-16.5 and the weaker L-2 ligand pool with log K'(cu2)(+L2) 11.6-13.6. The L-1 class bound on average 94% of dCu, with the ratio between L-1 and dCu constant and close to unity (1.15 = [L-1]:[dCu]). The concentrations of total ligands exceeded those of dCu at all depths, buffering Cu2+ concentrations ([Cu2+]) to femtomolar levels (i.e. pCu 14.1-15.7). Measurements using cathodic stripping voltammetry also identified natural copper-responsive peaks, which were attributed to thiourea- and glutathione-like thiols (TU and GSH, respectively), and Cu-binding humic substances (HScu). Concentrations of TU, GSH and HScu were determined by standard addition of model compounds in an attempt to identify Cu-binding ligands. HScu concentrations were generally higher at P26 than at P4, consistent with a marine origin of the humic material. Overall, HScu contributed to 1-27% of the total L concentration (L-T) and when combined with the two thiols contributed to up to 32% of L-T. This suggests other ligand types are responsible for the majority of dCu complexation in these waters, such as other thiols. Some potential candidates for detected, but unidentified, thiols are cysteine, 3-mercaptopropionic acid and 2-mercaptoethanol, all of which bind Cu. Significant correlation between the concentrations of TU-like thiols and L-1, along with the high log K'(cu)(2+)(L1) values, tentatively suggest that the electrochemical TU-type peak could be part of a larger, unidentified, high-affinity Cu compound, such as a methanobactin or porphyrin, with a stronger binding capability than typical thiols. This could imply that chalkophores may play a greater role in oceanic dCu complexation than previously considered. 
PY 2018
PD AUG
SO Marine Chemistry
SN 0304-4203
PU Elsevier Science Bv
VL 204
UT 000443668500004
BP 36
EP 48
DI 10.1016/j.marchem.2018.05.008
ID 72780
ER

EF