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Importance of refractory ligands and their photodegradation for iron oceanic inventories and cycling
- Source :
- Marine and Freshwater Research. 71:311
- Publication Year :
- 2020
- Publisher :
- CSIRO Publishing, 2020.
-
Abstract
- Iron is an essential micronutrient that limits primary production in up to 40% of the surface ocean and influences carbon dioxide uptake and climate change. Dissolved iron is mostly associated with loosely characterised organic molecules, called ligands, which define key aspects of the iron cycle such as its residence time, distribution and bioavailability to plankton. Models based on in situ ligand distributions and the behaviour of purified compounds include long-lived ligands in the deep ocean, bioreactive ligands in the surface ocean and photochemical processes as important components of the iron cycle. Herein, we further characterise biologically refractory ligands in dissolved organic matter (DOM) from the deep ocean and labile ligands in DOM from the surface ocean, and their photochemical and biological reactivities. Experimental results indicated that photodegradation of upwelled refractory iron-binding ligands can fuel iron remineralisation and its association with labile organic ligands, thus enhancing iron bioavailability in surface waters. These observations better elucidate the roles of biologically refractory and labile molecules and global overturning circulation in the ocean iron cycle, with implications for the initiation and sustainment of biological activity in iron-limited regions and the residence time of iron in the ocean.
- Subjects :
- 0106 biological sciences
chemistry.chemical_classification
Remineralisation
010504 meteorology & atmospheric sciences
Ecology
Chemistry
010604 marine biology & hydrobiology
fungi
Aquatic Science
Plankton
Oceanography
01 natural sciences
Deep sea
chemistry.chemical_compound
Iron cycle
Environmental chemistry
Dissolved organic carbon
Carbon dioxide
Organic matter
Ecology, Evolution, Behavior and Systematics
Refractory (planetary science)
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 13231650
- Volume :
- 71
- Database :
- OpenAIRE
- Journal :
- Marine and Freshwater Research
- Accession number :
- edsair.doi...........0e23f4e6d9513889b18f7dfd4dc38dc9
- Full Text :
- https://doi.org/10.1071/mf19213