Biogeochemical Characteristics of Western Tropical Atlantic Ocean Water Masses

Water masses are commonly identified according to their conservative parameters. However, there also studies that use non-conservative parameters, together with the ones, refine water identification. The aim of this study was analyze chemical properties in western tropical Atlantic Ocean (WTAO) inorganic nutrient concentration: nitrate-NO3–, phosphate-PO43–, and silicic acid-Si(OH)4, set a regional descriptive framework column view future comparative studies. We collected full-depth samples from 18 oceanographic stations latitudinal transect along 38°W, 02°S 15°N during PIRATA-BR XVII XVIII campaigns, November 2017 2018. have used data available GLODAPv.2 product improve characterization. Six were region based on values potential temperature, salinity, density, neutral density observed area CTD-O2 data: Tropical Surface (TSW); South North Central (SACW NACW, respectively); Antarctic Intermediate (AAIW); Deep (NADW); Bottom (AABW). Regarding content within each mass, our results showed TSW corresponds surface oligotrophic water; NACW SACW intermediate concentration between AAIW; AAIW highest phosphate-PO43– (~ 1.35 µmol kg–1) nitrate-NO3– (~30 kg–1); AABW, other hand, mass acid-Si(OH)4 80 kg–1), as well high 25 1.80 concentrations. Additionally, 300 650 m displays an increase concentrations north 5oN, associated low dissolved oxygen coupled Equatorial Under Current (NEUC). Long-term, sustained hydrographic ocean biogeochemistry observations key understand how climate change is affecting ocean, contribution that.