Iron is a key ingredient of many enzyme systems in the ocean, and thus plays a unique and important role in controlling its productivity. At the time marine life first evolved, iron was extremely abundant in the reduced form Fe( ii), but as photosynthetic organisms restructured the chemistry of the ocean through evolution of excess oxygen, it became less and less abundant because of the very low solubility of the Fe( iii) form. In the modern ocean, iron has become a rare trace element in spite of its huge relative abundance in the rocks and soils of the continents, with the result that continental weathering in the form of dust particles now represents the main external supply of this vital nutrient in the oceans. As a result of these self-engineered changes, marine phytoplankton had to adapt to a shortage of iron by developing much more efficient mechanisms for sequestering and using what little iron is available, and it has become one of the controlling factors for phytoplankton growth in large parts of the global ocean.
History
Publication title
Encyclopedia of Ecology
Volume
1-5
Editors
SE Jorgensen and BD Fath
Pagination
2028-2033
ISBN
9780444637680
Department/School
Australian Antarctic Program Partnership
Publisher
Elsevier Science Bv
Publication status
Published
Place of publication
Oxford
Extent
100
Rights statement
Copyright 2008 Elsevier B.V.
Socio-economic Objectives
180402 Antarctic and Southern Ocean oceanic processes, 180506 Oceanic processes (excl. in the Antarctic and Southern Ocean)