<p>Table S1. Physical and chemical characteristics of the epipelagic (from 10 to 200 m depth), mesopelagic (from 200 to 1000 m depth), bathypelagic (from</p><p>1000 to 2500 m depth) and abyssopelagic (>2500 m depth) layers along the North Atlantic latitudinal transect sampled during the Geotraces expedition. </p><p>ARCT - North Atlantic Arctic (70°N - 55°N), NADR - North Atlantic Drift (55°N - 40°N), NAG - North Atlantic Gyral (40°N - 12°N) and WTRA - </p><p>Western Tropical Atlantic (12°N - 12°S) province following the classification of oceanic provinces (Longhurst 1998). AOU – apparent oxygen utilization.</p><p>ARCT NADR NAG WTRA</p><p>Depth Layer range Temp Salinity AOU Temp Salinity AOU Temp Salinity AOU Temp Salinity AOU (m) ºC (μmol kg-1) ºC (μmol kg-1) ºC (μmol kg-1) ºC (μmol kg-1) Average 5.7 34.95 43.49 11.8 35.39 39.76 24.2 36.13 25.0 28.3 35.66 21.44 Upper sd 0.7 0.12 4.38 3.6 0.57 18.80 4.1 1.16 7.9 0.7 0.67 3.61 10-75 m Epi min 4.9 34.81 35.71 4.5 34.60 13.60 17.5 32.12 14.8 26.8 34.13 13.39 max 6.8 35.15 50.41 15.3 36.07 95.86 29.3 36.92 47.2 29.1 36.36 28.01 Average 5.4 34.99 49.84 11.1 35.45 54.41 20.9 36.73 38.2 18.4 35.93 98.51 Lower sd 0.9 0.11 4.10 4.0 0.54 7.53 3.2 0.26 13.5 5.3 0.54 38.14 75-200m Epi min 4.2 34.83 41.57 3.8 34.70 43.08 16.7 36.04 15.1 10.3 34.95 32.78 max 6.7 35.15 56.34 14.9 36.03 69.74 27.6 37.27 81.2 26.3 36.49 146.62 Average 4.5 34.94 62.48 7.8 35.16 90.63 15.0 36.06 90.9 8.6 34.85 169.26 200-1000 sd 0.8 0.07 6.50 3.7 0.38 28.32 4.1 0.62 45.7 2.3 0.25 18.74 Meso m min 3.9 34.89 49.30 3.6 34.77 55.60 5.2 34.66 38.1 4.7 34.51 121.86 max 6.5 35.12 77.99 14.2 35.91 144.91 21.0 37.04 185.4 14.5 35.77 199.76 Average 3.3 34.91 73.01 3.8 34.92 75.13 4.5 35.00 99.3 4.2 34.92 115.80 1000-2500 sd 0.5 0.02 4.38 0.4 0.02 4.73 1.0 0.05 20.9 0.7 0.10 30.25 Bathy m min 1.5 34.87 62.80 3.1 34.87 60.69 3.1 34.81 81.7 3.0 34.66 85.19 max 3.9 34.96 76.68 4.8 34.98 86.43 7.8 35.21 171.8 5.2 35.01 178.92 Average 1.9 34.90 68.63 2.4 34.91 75.57 2.4 34.90 97.1 2.4 34.90 101.24 2500-6000 sd 0.5 0.01 4.09 0.4 0.01 3.97 0.3 0.03 7.4 0.4 0.04 9.10 Abysso m min 1.44 34.88 64.79 2.0 34.89 67.29 1.9 34.83 84.6 1.3 34.77 90.96 max 2.8 34.93 77.05 3.3 34.93 82.51 3.4 34.96 117.2 3.1 34.95 137.05 Average, Standard Deviation (sd) and range (min-max value) are indicated for all the parameters.</p>