In some areas of the ocean, conditions allow phytoplankton to thrive. Phytoplankton are small, photosynthetic organisms that live in the top, sunlit layers of water.

Question

phytoplankton
Image courtesy of NOAA Alaska Fisheries Science Center MESA Project

In areas with large numbers of phytoplankton, there are also large numbers of fish, marine mammals, and other animals. For example, the west coast of the U.S. has many fisheries due to the large numbers of phytoplankton in those waters. What provides the energy to support so many animals in these areas?
A.
minerals, because minerals dissolved in the water are used by phytoplankton to make sugars that other animals eat
B.
plants, because when phytoplankton die they are absorbed by plants that are then eaten by fish and other animals
C.
nutrient-rich soil, because coastal areas have an abundance of nutrient-rich soil that phytoplankton and other animals use as food
D.
the Sun, because phytoplankton use its energy to perform photosynthesis before being consumed by animals higher in the food chain

Answer 1

The correct answer is:

D. the Sun, because phytoplankton use its energy to perform photosynthesis before being consumed by animals higher in the food chain.

Phytoplankton are primary producers that convert sunlight into energy through photosynthesis, which then supports a wide range of marine life in the ecosystem.