The Ferrous Wheel: A Perspective on the Iron Cycle

While you won’t find the ferris wheel that is a staple of the county fair, this coggle will introduce you to a different kind of ferrous wheel- the cycle of the transition metal, iron. Iron naturally exists in two states: ferrous iron, Fe(II), and ferric iron (III). These forms can exist as ions, or minerals, where they are bound to oxides. Iron is not only important to human life where it serves as cofactors in chemical reactions, but also to many microbes, where it drives their metabolism. It is prevalent in terrestrial environments, in oceans, and even the atmosphere. Preservation of the iron cycle is critical to the fluidity of geochemical cycling, as it plays a role in nitrogen cycling and limits phytoplankton’s ability to perform photosynthesis.

In this coggle we describe how microbes facilitate the anaerobic transition between ferric and ferrous iron, how microbes covert ions to minerals, and how iron enters the cycle. We presented this research in the framework iron cycling in the ocean, (including the role of phytoplankton), but the microbial iron cycle is diverse, and one step can happen via multiple mechanisms. This leaves much more to learn and explore, and we urge you to use this project as your first step into the ferrous wheel.

Begin on the left side with the entry “Mineral Iron II Flux”, and follow the blue arrows around the ferrous wheel. Click and drag to view different parts of the coggle


Team: Ben Hedges, Bayli Mohl, Karen Biondich, Courtney Hill and Mark Velasco

Scavenger Hunt: challenge yourself to complete these by reviewing all of the posts

  1. What method of iron oxidation was likely the first, evolving in ancient oceans?
  2. How can diatoms uptake iron into their cell bodies?
  3. Do anaerobic iron reducers need to import the iron?
  4. What is it about sea water that allows for the rapid oxidation of iron?
  5. Which ocean experiences the greatest input of aerial dust from the Earth’s major deserts?

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