Microbes, which have a fundamental role in biogeochemical cycles and marine ecosystems, are fac-
ing major environmental changes. In the Southern Ocean (SO), the increasing temperatures are
accelerating the melting of ice sheets and glaciers with a consequent release of nutrients. We focus
on Iron, known for limiting plankton productivity and the biological pump of C in the SO. Knowl-
edge on how taxonomically and functionally microbes will respond to these changes is presently
poorly understood. Studying these communities is a challenging task in the SO as the technical
infrastructure is often insufficient. This project aims to test a cryopreservation and resuscitation
protocol which allows to perform measurements in the home lab. Resuscitated communities from
three different SO sites were used to i) determine the growth limiting factors and to ii) measure
bacterial activity close to in situ conditions via Redox Sensor and BONCAT techniques. Results
show that bacterial responses to nutrient addition are site-specific; bacteria from the Iron fertilized
zone present greater growth rates and respiration compared to the other sites. The protocol used
was suitable for this kind of analysis but a comparison with in situ community would be required
for a greater reliability. These findings open a promising future in the study of remote microbes.
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