Correct Option (B)
Marineupwelling zonesare regions where deep, cold,nutrient-rich water risesto the ocean surface. This process brings essentialdissolved nutrients, such as nitrates, phosphates, and silicates, from the deeper layers to the sunlit euphotic zone. These nutrients are crucial for the growth ofphytoplankton, which are microscopic marine algae and the primary producers at the base of the marine food web. The increased availability of nutrients fuels rapid phytoplankton growth, leading tohigh primary productivityand subsequently supporting a rich diversity of marine life, including zooplankton, fish, and marine mammals. Therefore, statement2is correct.
Incorrect Options
Statement 1: Upwelling primarily involves the vertical movement of water masses and dissolved substances. While microorganisms are ubiquitous in the ocean, upwelling is not primarily characterized by bringing decomposer microorganisms to the surface in a manner that significantly increases overall marine productivity. The key factor is the supply of inorganic nutrients for primary production.
Statement 3: Upwelling does not typically bring bottom-dwelling organisms (benthic species) to the surface. The process is a large-scale movement of water, not a physical displacement of macroscopic organisms from the seabed to the surface. The impact on productivity is through the nutrient supply, not the direct transport of benthic life.
Since statements 1 and 3 are incorrect, options A (1 and 2), C (2 and 3), and D (3 only) are incorrect.