In the context of ecosystem productivity, marine upwelling zones are important as they increase the marine productivity by bringing the 1. decomposer microorganisms to the surface. 2. nutrients to the surface 3. Bottom-dwelling organisms to the surface. Which of the statements given above is/ correct?

Marine upwelling is a process where winds and Earth's rotation drive surface waters offshore, causing deep, cold water to rise and replace it [4]. This deep water is rich in essential nutrients like nitrogen and phosphorus, which accumulate at depth due to the decomposition of sinking organic matter [1]. When these nutrients are brought to the sunlit euphotic zone, they "fertilize" the water, fueling the explosive growth of phytoplankton, the primary producers [3]. While upwelling moves water masses, its primary contribution to productivity is the transport of nutrients, not the relocation of decomposer microorganisms or benthic (bottom-dwelling) organisms to the surface [3]. In fact, upwelling can sometimes negatively impact local populations by washing larvae away from their habitats [4]. Thus, only statement 2 is correct regarding the mechanism of increased productivity.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 3: MAJOR BIOMES > Plant Life in a marine ecosystem > p. 29
2. [4] https://education.nationalgeographic.org/resource/upwelling/
3. [3] https://oceanexplorer.noaa.gov/ocean-fact/upwelling/