Iron is an important micronutrient required by marine microorganisms. The Southern Ocean is an ecosystem where primary production is limited by the availability of iron, but how microorganisms in this region adapt to low‐iron conditions or respond to episodic iron inputs is understudied. We tested how external iron additions would impact bacterial production of siderophores during phytoplankton growth using shipboard incubatio...

The metabolism of heterotrophic bacteria acts as a key control on the turnover of organic matter in the ocean. However, much remains unknown about how nutrient availability, particularly iron concentration, impacts bacterial growth. In the dimly lit waters of the lower photic and upper mesopelagic zones, the attenuation of sinking particulate flux is intense, due in part to remineralization by heterotrophic bacteria. In the No...