Iron-binding ligands in the Southern California Current System : mechanistic studies
Date
2016-03-15Author
Bundy, Randelle M.
Concept link
Jiang, Mingshun
Concept link
Carter, Melissa
Concept link
Barbeau, Katherine A.
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/8765As published
https://doi.org/10.3389/fmars.2016.00027DOI
10.3389/fmars.2016.00027Keyword
California Current Ecosystem; Long term ecological research; Iron limitation; Dissolved iron-binding ligands; Multiple analytical windows; ElectrochemistryAbstract
The distributions of dissolved iron and organic iron-binding ligands were examined in water column profiles and deckboard incubation experiments in the southern California Current System (sCCS) along a transition from coastal to semi-oligotrophic waters. Analysis of the iron-binding ligand pool by competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) using multiple analytical windows (MAWs) revealed three classes of iron-binding ligands present throughout the water column (L1−L3), whose distributions closely matched those of dissolved iron and nitrate. Despite significant biogeochemical gradients, ligand profiles were similar between stations, with surface minima in strong ligands (L1 and L2), and relatively constant concentrations of weaker ligands (L3) down to 500 m. A phytoplankton grow-out incubation, initiated from an iron-limited water mass, showed dynamic temporal cycling of iron-binding ligands. A biological iron model was able to capture the patterns of the strong ligands in the grow-out incubation relatively well with only the microbial community as a biological source. An experiment focused on remineralization of particulate organic matter showed production of both strong and weak iron-binding ligands by the heterotrophic community, supporting a mechanism for in-situ production of both strong and weak iron-binding ligands in the subsurface water column. Photochemical experiments showed a variable influence of sunlight on the degradation of natural iron-binding ligands, providing some evidence to explain differences in surface ligand concentrations between stations. Patterns in ligand distributions between profiles and in the incubation experiments were primarily related to macronutrient concentrations, suggesting microbial remineralization processes might dominate on longer time-scales over short-term changes associated with photochemistry or phytoplankton growth.
Description
© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Marine Science 3 (2016): 27, doi:10.3389/fmars.2016.00027.
Collections
Suggested Citation
Frontiers in Marine Science 3 (2016): 27The following license files are associated with this item:
Related items
Showing items related by title, author, creator and subject.
-
The composition of dissolved iron in the dusty surface ocean : an exploration using size-fractionated iron-binding ligands
Fitzsimmons, Jessica N.; Bundy, Randelle M.; Al-Subiai, Sherain N.; Barbeau, Katherine A.; Boyle, Edward A. (2014-09)The size partitioning of dissolved iron and organic iron-binding ligands into soluble and colloidal phases was investigated in the upper 150 m of two stations along the GA03 U.S. GEOTRACES North Atlantic transect. The ... -
Profiles of dissolved iron-binding ligands and their conditional stability constants from R/V Knorr KN199-04, KN204-01, subtropical North Atlantic Ocean, 2010-2011 (U.S. GEOTRACES NAT project)
Buck, Kristen (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2022-05-16)For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/3844 -
Hydrographic conditions near the coast of northwestern Baja California : 1997–2004
Perez-Brunius, Paula; Lopez, Manuel; Pineda, Jesus (2005-05-18)The effects of the 1997-98 and 2002-04 El Ni˜no on the upper waters in the con- tinental shelf and slope regions off northwestern Baja California are explored with data from eight cruises taken in late spring from 1998 ...