Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect
Organic ligands form strong complexes with many trace elements in seawater. Various metals can compete for the same ligand chelation sites, and the final speciation of bound metals is determined by relative binding affinities, concentrations of binding sites, uncomplexed metal concentrations, and as...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2016-11-01
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| Series: | Frontiers in Marine Science |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fmars.2016.00243/full |
| _version_ | 1818952116010483712 |
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| author | Rene M Boiteau Rene M Boiteau Claire P Till Angel Ruacho Randelle M Bundy Nicholas J Hawco Nicholas J Hawco Amy M. McKenna Katherine Barbeau Kenneth Bruland Mak Saito Daniel James Repeta |
| author_facet | Rene M Boiteau Rene M Boiteau Claire P Till Angel Ruacho Randelle M Bundy Nicholas J Hawco Nicholas J Hawco Amy M. McKenna Katherine Barbeau Kenneth Bruland Mak Saito Daniel James Repeta |
| author_sort | Rene M Boiteau |
| collection | DOAJ |
| description | Organic ligands form strong complexes with many trace elements in seawater. Various metals can compete for the same ligand chelation sites, and the final speciation of bound metals is determined by relative binding affinities, concentrations of binding sites, uncomplexed metal concentrations, and association/dissociation kinetics. Different ligands have a wide range of metal affinities and specificities. However, the chemical composition of these ligands in the marine environment remains poorly constrained, which has hindered progress in modeling marine metal speciation. In this study, we detected and characterized natural ligands that bind copper (Cu) and nickel (Ni) in the eastern South Pacific Ocean with liquid chromatography tandem inductively coupled plasma mass spectrometry (LC-ICPMS), and high resolution electrospray ionization mass spectrometry (ESIMS). Dissolved Cu, Ni, and ligand concentrations were highest near the coast. Chromatographically unresolved polar compounds dominated ligands isolated near the coast by solid phase extraction. Offshore, metal and ligand concentrations decreased, but several new ligands appeared. One major ligand was detected that bound both Cu2+ and Ni2+. Based on accurate mass and fragmentation measurements, this compound has a molecular formula of C20H21N4O8S2 + M+ (M = metal isotope) and contains several azole-like metal binding groups. Additional lipophilic Ni complexes were also present only in oligotrophic waters, with masses of 649, 698, and 712 m/z (corresponding to the 58Ni metal complex). Molecular formulae of C32H54N3O6S2Ni+ and C33H56N3O6S2Ni+ were determined for two of these compounds. Addition of Cu and Ni to the samples also revealed the presence of additional compounds that can bind both Ni and Cu. Although these specific compounds represent a small fraction of the total dissolved Cu and Ni pool, they highlight the compositional diversity and spatial heterogeneity of marine Ni and Cu ligands, as well as variability in the extent to which different metals in the same environment compete for ligand binding. |
| first_indexed | 2024-12-20T09:45:15Z |
| format | Article |
| id | doaj.art-38b6241f017c40a7badd7f06b2657431 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-12-20T09:45:15Z |
| publishDate | 2016-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-38b6241f017c40a7badd7f06b26574312022-12-21T19:44:45ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452016-11-01310.3389/fmars.2016.00243223051Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transectRene M Boiteau0Rene M Boiteau1Claire P Till2Angel Ruacho3Randelle M Bundy4Nicholas J Hawco5Nicholas J Hawco6Amy M. McKenna7Katherine Barbeau8Kenneth Bruland9Mak Saito10Daniel James Repeta11Woods Hole Oceanographic InstitutionMassachusetts Institute of TechnologyUniversity of California Santa CruzUniversity of California San DiegoWoods Hole Oceanographic InstitutionWoods Hole Oceanographic InstitutionMassachusetts Institute of TechnologyFlorida State UniversityUniversity of California San DiegoUniversity of California Santa CruzWoods Hole Oceanographic InstitutionWoods Hole Oceanographic InstitutionOrganic ligands form strong complexes with many trace elements in seawater. Various metals can compete for the same ligand chelation sites, and the final speciation of bound metals is determined by relative binding affinities, concentrations of binding sites, uncomplexed metal concentrations, and association/dissociation kinetics. Different ligands have a wide range of metal affinities and specificities. However, the chemical composition of these ligands in the marine environment remains poorly constrained, which has hindered progress in modeling marine metal speciation. In this study, we detected and characterized natural ligands that bind copper (Cu) and nickel (Ni) in the eastern South Pacific Ocean with liquid chromatography tandem inductively coupled plasma mass spectrometry (LC-ICPMS), and high resolution electrospray ionization mass spectrometry (ESIMS). Dissolved Cu, Ni, and ligand concentrations were highest near the coast. Chromatographically unresolved polar compounds dominated ligands isolated near the coast by solid phase extraction. Offshore, metal and ligand concentrations decreased, but several new ligands appeared. One major ligand was detected that bound both Cu2+ and Ni2+. Based on accurate mass and fragmentation measurements, this compound has a molecular formula of C20H21N4O8S2 + M+ (M = metal isotope) and contains several azole-like metal binding groups. Additional lipophilic Ni complexes were also present only in oligotrophic waters, with masses of 649, 698, and 712 m/z (corresponding to the 58Ni metal complex). Molecular formulae of C32H54N3O6S2Ni+ and C33H56N3O6S2Ni+ were determined for two of these compounds. Addition of Cu and Ni to the samples also revealed the presence of additional compounds that can bind both Ni and Cu. Although these specific compounds represent a small fraction of the total dissolved Cu and Ni pool, they highlight the compositional diversity and spatial heterogeneity of marine Ni and Cu ligands, as well as variability in the extent to which different metals in the same environment compete for ligand binding.http://journal.frontiersin.org/Journal/10.3389/fmars.2016.00243/fullCopperNickelGEOTRACESEastern PacificMetal competitionmarine ligands |
| spellingShingle | Rene M Boiteau Rene M Boiteau Claire P Till Angel Ruacho Randelle M Bundy Nicholas J Hawco Nicholas J Hawco Amy M. McKenna Katherine Barbeau Kenneth Bruland Mak Saito Daniel James Repeta Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect Frontiers in Marine Science Copper Nickel GEOTRACES Eastern Pacific Metal competition marine ligands |
| title | Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect |
| title_full | Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect |
| title_fullStr | Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect |
| title_full_unstemmed | Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect |
| title_short | Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect |
| title_sort | structural characterization of natural nickel and copper binding ligands along the us geotraces eastern pacific zonal transect |
| topic | Copper Nickel GEOTRACES Eastern Pacific Metal competition marine ligands |
| url | http://journal.frontiersin.org/Journal/10.3389/fmars.2016.00243/full |
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