AICE Marine Science Practice Exam

Zooplankton primarily feed on phytoplankton, which are microscopic organisms that perform photosynthesis and form the base of the marine food web. By grazing on phytoplankton, zooplankton play a crucial role in nutrient cycling and energy transfer within aquatic ecosystems. This grazing habit allows them to obtain energy from the primary producers in their environment.

The feeding strategies of zooplankton can vary, but they are generally classified as filter feeders or grazers. Some zooplankton, like copepods, use their specialized structures to filter small particles, including phytoplankton, from the water column. This feeding behavior is essential for maintaining the balance of aquatic ecosystems, as it influences phytoplankton populations and supports higher trophic levels.

The other options describe feeding habits that do not accurately represent the primary way in which zooplankton acquire nutrients. For instance, while some organisms may scavange or show predatory behavior, those actions are not the defining characteristics of zooplankton as a whole. Therefore, the description of zooplankton grazing on phytoplankton is the most accurate representation of their feeding habits.