Sea water samples were collected during the RV SONNE cruise SO288 (15 January 2022–15 February 2022) within the framework of the HOMER project in the Southeast Pacific off Chile . At three stations, water samples were collected at 12 depths throughout the water column using standard 12 L Niskin-type bottles attached to a CTD rosette and represented the different pelagic zones: 25 m and 100 m (epipelagic), 250, 500, 750 and 1,000 m (mesopelagic), 1,500- 3800 m (bathypelagic; here different depths were sampled due to differences in bathymetry), and 4,000, 4,500 and 5,000 m (abyssopelagic). Temperature, oxygen, and pressure were measured using a Sea-Bird SBE 9-plus CTD system (Sea-Bird Electronics, Inc.), and chlorophyll a (Chl a) concentrations were detected using a WETStar fluorometer (WET Labs).

PCA1 loadings used for DI calculation AsX 0,183566944GlX 0,180226586Ser 0,123932867Gly -0,941383783Thr 0,07770909Arg 0,028766701Ala 0,125898931GABA 0,006081105Tyr 0,035912614Val 0,045953695Iso 0,044019614Phe 0,034636789Leu 0,054462237