Deployment: SERIES_ElPuma

CRUISE OBJECTIVES:
The productivity of large parts of the North Pacific Ocean is limited by iron. In this system, iron is naturally
supplied by atmospheric deposition. Such natural iron fertilization is presumed to enhance plankton
productivity. Given the episodic nature of these natural iron delivery events, it is impossible to plan in
advance a cruise to study their impact on the ocean productivity. The goal of this project is to artificially
reproduce and study the impact of such an event by releasing a small amount of iron in a ca. 64 km2 area of
the subarctic Northeastern Pacific. An inert gas (SF6) will be added with the iron and serve as a tracer of
the patch. Previous iron enrichment experiments conducted in other parts of the global ocean resulted in
important increases in phytoplankton biomass. The iron-induced increase in plankton productivity may
also change the capacity of the ocean to absorb or produce climatically relevant gases such as CO2 and
dimethylsulfide (DMS). Therefore, an important part of our project is to quantify the influence of iron on
the dynamics of these gases, and on their concentrations in the atmosphere. In contrast with previous iron
enrichment studies, oceanographic measurements will be complemented by a series of atmospheric
measurements during SERIES.