At each station, seawater was collected for trace metals sampling at 20 m depth using a Teflon pump (Furon®) with a 40 m Teflon tube connected with a AcroPakTM 1500 capsule w/Supor Memb 0.8/0.2 μm filter. The pump was left to pump to rinse the inner hose and 1 L sample was collected in LDPE bottles (NALGENE) and stored at -20oC until the land-based laboratory analysis. The material was previously cleaned following the trace metals GEOTRACES protocol and the experiments were done in Class 100 clean laboratory or trace metal analysis (QUIMA- IOCAG TM lab).