AP BIOLOGY

Detailed explanation-1: -Parts of the Antarctic Circumpolar Current flow northward and move into the Indian and Pacific Oceans. As the deep, cold water travels through the oceans, it mixes with warmer water. The water eventually becomes warm enough to rise, creating a slow upwelling that brings nutrients to the surface.

Detailed explanation-2: -More salt makes water heavier and therefore denser. These two factors, temperature and salinity, are the main driving forces behind Earth’s ocean conveyor belt, which is a huge water circulation system in the deep ocean that moves water around the globe.

Detailed explanation-3: -There are two main types of ocean currents: surface currents and deep ocean currents. Surface currents are driven by global wind systems that are fueled by energy from the sun.

Detailed explanation-4: -Nutrients in the ocean are cycled by a process known as biological pumping, whereby plankton extract the nutrients out of the surface water and combine them in their organic matrix. Then when the plants die, sink and decay, the nutrients are returned to their dissolved state at deeper levels of the ocean.