Diel changes in trace metal concentration and distribution in coastal waters: Catalina Island as a study case.
Environ Sci Technol
; 48(14): 7730-7, 2014 Jul 15.
Article
em En
| MEDLINE
| ID: mdl-24952958
ABSTRACT
Understanding biogeochemical cycling of trace metals in the ocean requires information about variability in metal concentrations and distribution over short, e.g., diel, time scales. Such variability and the factors that influence it are poorly characterized. To address this shortcoming, we measured trace metal concentrations in the total dissolved, colloidal, and soluble fractions every 3-4 h for several consecutive days and nights in surface waters from a coastal station. Our results show that both the concentration and the size partitioning of some biologically essential (Fe, Cu, Co, and Cd) and anthropogenic (Pb) metals are subjected to diel variations that may be related to both inorganic and biological processes (e.g., photolysis of high-molecular-weight dissolved organic matter, photoinduced reduction/oxidation of metal(hydrous)oxides, uptake by growing phytoplankton, degradation of organic matter, lysis, and grazing). The largest fluctuations were observed in the soluble and colloidal pools. Soluble Fe varied during the day-night cycle by a factor of 40, and the contribution of colloidal Pb to the total dissolved fraction increased from 6±3% during the day to as much as 70-80% during the night. Our results suggest that changes occurring over time scales of hours need to be considered when collecting and interpreting trace metal data from the surface ocean.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Água do Mar
/
Ecossistema
/
Ilhas
/
Metais
País/Região como assunto:
America do norte
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Estados Unidos