Minhan DaiThe oligotrophic ocean, mostly located in subtropical regions occupies ~30% of the Earth surface and has been conventionally regarded as an ocean desert. It is characterized by permanent stratification, nutrient depletion and extremely low net biological production, and hence, contributes little to carbon export from surface to deep waters at per unit area. Emerging evidence has shown that this oceanic system has a much larger dynamic range of nutrient inputs from different sources in addition to those from depth. These differently sourced nutrients withdiffering stoichiometry may stimulate biological productions in different community structures and drive the carbon export at various depth horizons within the sunlit euphotic zone (EZ). Hence, the EZ is better characterized by a two-layered structure with a nutrient nutrient-depleted layer (NDL) above the nutricline and a nutrient replete layer (NRL) across the nutricline to the base of the EZ.