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Microbial control of diatom bloom dynamics in the open ocean
Author(s) -
Boyd Philip W.,
Strzepek Robert,
Chiswell Steve,
Chang Hoe,
DeBruyn Jennifer M.,
Ellwood Michael,
Keenan Sean,
King Andrew L.,
Maas Elisabeth W.,
Nodder Scott,
Sander Sylvia G.,
Sutton Philip,
Twining Benjamin S.,
Wilhelm Steven W.,
Hutchins David A.
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2012gl053448
Subject(s) - diatom , bloom , phytoplankton , spring bloom , biogeochemical cycle , algal bloom , oceanography , environmental science , biogeochemistry , competition (biology) , iron fertilization , ecology , carbon cycle , biology , nutrient , geology , ecosystem
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.