@article{fdi:010069257,
  title = {{D}ynamics of dissolved major ({N}a, {K}, {C}a, {M}g, and {S}i) and trace ({A}l, {F}e, {M}n, {Z}n, {C}u, and {C}r) elements along the lower {O}rinoco {R}iver},
  author = {{M}ora, {A}. and {M}ahlknecht, {J}. and {B}aquero, {J}. {C}. and {L}araque, {A}lain and {A}lfonso, {J}. {A}. and {P}isapia, {D}. and {B}alza, {L}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his study addresses the changes in dissolved major and trace element concentrations along the {O}rinoco {R}iver, including the mixing zone between the {O}rinoco and {A}pure {R}ivers. {W}ater samples from the {A}pure and {O}rinoco {R}ivers were collected monthly in four sectors over a period of 15months. {A}uxiliary parameters (p{H}, dissolved oxygen, conductivity, and temperature), total suspended sediments, dissolved organic carbon ({DOC}), and major ({N}a, {K}, {C}a, {M}g, and {S}i) and trace ({A}l, {F}e, {M}n, {Z}n, {C}u, and {C}r) element concentrations were measured in all sectors. {T}he relative contribution of both rivers after the {A}pure-{O}rinoco confluence was determined using {C}a as a tracer. {M}oreover, a mixing model was developed to determine whether dissolved species exhibit a conservative behavior during mixing. {T}he results indicate that {DOC} is removed from waters during the {A}pure-{O}rinoco mixing, probably due to absorption of {DOC} on mineral phases supplied by the {A}pure {R}iver. {D}issolved {N}a, {C}a, and {M}g behave conservatively during the mixing processes, and their concentrations are controlled by a dilution process. {T}he anomaly in the temporal pattern of {K} in the {O}rinoco is caused by the input of biogenic {K} originating from the {A}pure {R}iver during the high-water stage. {T}he loss of dissolved {S}i during the low-water stage can be explained by the uptake of {S}i by diatoms. {D}issolved {M}n, {Z}n, {A}l, and {F}e showed a non-conservative behavior during the {A}pure-{O}rinoco mixing. {T}he removal of {M}n and {Z}n from the dissolved phase can be explained by the formation of {M}n-oxyhydroxides and the scavenging of {Z}n onto {M}n oxides. {D}issolved {F}e is controlled by redox processes, although the removals of {F}e and {A}l due to the preferential adsorption of large organometallic complexes by mineral surfaces after the {A}pure-{O}rinoco confluence can affect the mobility of both elements during transport. {T}he conservative behavior shown by {C}u and {C}r can be related to the tendency of both elements to be complexed with small organic colloids, which are not preferentially adsorbed by clays.},
  keywords = {major elements ; mixing zone ; organic matter ; {O}rinoco {R}iver ; trace elements ; {VENEZUELA} ; {GUYANES} {PLATEAU} ; {APURE} {COURS} {D}'{EAU} ; {ORENOQUE} {COURS} {D}'{EAU}},
  booktitle = {},
  journal = {{H}ydrological {P}rocesses},
  volume = {31},
  numero = {3},
  pages = {597--611},
  ISSN = {0885-6087},
  year = {2017},
  DOI = {10.1002/hyp.11051},
  URL = {https://www.documentation.ird.fr/hor/fdi:010069257},
}