Microbial control of diatom bloom dynamics in the open ocean
Article first published online: 19 SEP 2012
©2012. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 39, Issue 18, September 2012
How to Cite
2012), Microbial control of diatom bloom dynamics in the open ocean, Geophys. Res. Lett., 39, L18601, doi:10.1029/2012GL053448., et al. (
- Issue published online: 19 SEP 2012
- Article first published online: 19 SEP 2012
- Manuscript Accepted: 6 AUG 2012
- Manuscript Received: 2 AUG 2012
 Diatom blooms play a central role in supporting foodwebs and sequestering biogenic carbon to depth. Oceanic conditions set bloom initiation, whereas both environmental and ecological factors determine bloom magnitude and longevity. Our study reveals another fundamental determinant of bloom dynamics. A diatom spring bloom in offshore New Zealand waters was likely terminated by iron limitation, even though diatoms consumed <1/3 of the mixed-layer dissolved iron inventory. Thus, bloom duration and magnitude were primarily set by competition for dissolved iron between microbes and small phytoplankton versus diatoms. Significantly, such a microbial mode of control probably relies both upon out-competing diatoms for iron (i.e.,K-strategy), and having high iron requirements (i.e.,r-strategy). Such resource competition for iron has implications for carbon biogeochemistry, as, blooming diatoms fixed three-fold more carbon per unit iron than resident non-blooming microbes. Microbial sequestration of iron has major ramifications for determining the biogeochemical imprint of oceanic diatom blooms.