2024-03-28T11:52:37Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/524862018-08-17T06:45:35Zcom_10261_47com_10261_8col_10261_300
Lorenzo, J. I.
Nieto-Cid, Mar
Álvarez-Salgado, Xosé Antón
Pérez, P.
Beiras, Ricardo
2012-06-28T11:34:28Z
2012-06-28T11:34:28Z
2007
Marine Chemistry 103(1-2): 61-75 (2007)
0304-4203
http://hdl.handle.net/10261/52486
10.1016/j.marchem.2006.05.009
The capacity of natural dissolved organic matter (DOM) produced during the onset, development and decay of a simulated
bloom of the marine diatom Skeletonema costatum to complex free copper has been followed for a 2 week period. Copper binding
capacity of the culture was measured by anodic stripping voltammetry (ASV) with a hanging mercury drop electrode (HMDE). The
concentration of dissolved organic carbon (DOC) and two fluorophores, M (humic-like, Ex/Em: 320 nm/410 nm) and T (proteinlike,
Ex/Em: 280 nm/350 nm), were followed during the course of the incubation. Models using DOC concentrations alone could
not accurately predict the complexing capacity of the culture, especially at the end of the bloom, and better predictions were
obtained when fluorescence measurements were considered. They were helpful in characterising two types of copper ligands
produced in the culture. The first type, traced by the fluorescence of peak T, was related to labile DOC directly exuded by
phytoplankton. The second type, traced by the fluorescence of peak M, was the refractory humic-like material presumably
produced in situ as a by-product of the bacterial degradation of phytogenic materials. During the onset and development of the
bloom (days 0 to 7), the fluorescence of peak T explains 60–80% of the total complexing capacity of the culture, suggesting that
exuded “protein-like” compounds among other exuded complexing agents efficiently complexed free copper. On the contrary,
during the decay (days 8 to 13), these ligands were replaced by humic substances as the complexing agent for copper.
eng
openAccess
Dissolved organic matter
Phytoplankton culture
Ligands
Fluorescence
Voltammetry
Contrasting complexing capacity of dissolved organic matter produced during the onset, development and decay of a simulated bloom of the marine diatom Skeletonema costatum
artículo