Cruises and sample collection
A cruise was carried out on August 7, 2017 on R/V Mediterranean Explorer to study the photic zone in the Eastern Mediterranean at high depth resolution. Genetic data and nano-SIMS measurements were used to infer and quantify mixotrophy by Prochlorococcus at the base of the photic zone.
Water samples were collected using a 12-bottle rosette with 8 L Niskin bottles. Sampling depths were selected based on real-time data from a Conductivity, Temperature, Depth (CTD) profiler (Seabird 19 Plus) from the down-cast before each sample collection in the up-cast. The continuous data were processed using custom Excel files taking into account the location of each sensor and the sensor delay, and binned over 1-meter intervals.