Fig. 7.

Left: Spectra from IRAM PdBI showing intense water emission in galaxies at redshift $z>3$ (reprinted from Omont et al. 2013). H₂O lines are among the strongest molecular lines in high-z U/LIRGs. Right: Metallicity estimates for local U/LIRGs (reprinted from Pereira-Santaella et al. 2017). With OASIS we will have the ability to measure water and fine structure lines of O, N and C in a significant sample ($\sim 30\text{–}100$) of intermediate redshift galaxies probing the most recent 5 billion years of the Universe during which the star formation activity slowly decreased to reach the levels seen today