Sequestration efficiency in the iron-limited North Atlantic: Implications for iron supply mode to fertilized blooms

• Published in: Geophysical Research Letters
• Main Authors: Le Moigne, Frederic A. C., Moore, C. Mark, Sanders, Richard J., Villa-alfageme, Maria, Steigenberger, Sebastian, Achterberg, Eric P.
• Format: Text
• Language: English
• Published: Amer Geophysical Union 2014
• Subjects: envir; geo; North Atlantic
• Online Access: https://doi.org/10.1002/2014GL060308; https://archimer.ifremer.fr/doc/00290/40112/39249.pdf; https://archimer.ifremer.fr/doc/00290/40112/39250.docx

Estimates of the amount of carbon sequestered in the ocean interior per unit iron (Fe) supplied, as quantified by the sequestration efficiency (C-effx), vary widely. Such variability in C-effx has frequently been attributed to estimate uncertainty rather than intrinsic variability. Here we derive new estimates of C-effx for the subpolar North Atlantic, where Fe stressed conditions have recently been demonstrated. Derived values of C-effx from across the region, including areas subject to atypical external Fe fertilization events during the year of sample collection (2010), ranged from 17 to 19 kmol C (mol Fe-1). Comparing these estimates with values from other systems, considered in the context of variable bloom durations in the different oceanographic settings, we suggest that apparent variability in C-effx may be related to the mode of Fe delivery.