Final answer:
Salinity and temperature greatly influence ocean water density, driving deep-ocean circulation. Cold, dense water at the Subtropical Convergence demonstrates how these factors can lead to upwelling and affect marine biodiversity. Different ocean zones host diverse biomes adapted to specific conditions like light availability and pressure.
Step-by-step explanation:
Salinity and temperature are the two most important factors in creating the density differences that result in deep-ocean circulation.
The deep ocean is primarily influenced by variations in salinity and temperature, which affect the density of seawater. Denser water tends to sink, creating a driving force for deep-ocean circulation. This is exemplified at the Subtropical Convergence, where cold, dense waters of the Southern Ocean sink below warmer waters, leading to upwelling and high productivity. Similar to terrestrial ecosystems where altitude influences organismal diversity, changes in water depth can result in environmental differences impacting the distribution of marine life.
Moreover, due to the lack of light penetration, photosynthesis is mainly restricted to the euphotic zone, leaving deeper water zones to rely on material sinking from above or on chemosynthesis. Various biomes exist within the ocean, with coral reefs and estuaries near the surface and deep ocean ecosystems marked by unique species adapted to dark, high-pressure environments. Understanding these factors is crucial, as aquatic systems, including deep-ocean zones, play vital roles in global climate and biodiversity.