Freshwater Ecosystems
Read the passage below and answer the questions that follow.
Aquatic ecosystems contain several types of organisms that are grouped by their location and by their adaptations. Three groups of aquatic organisms include plankton, nekton, and benthos. Plankton are the organisms that float near the surface of the water. Two types of plankton are microscopic plants called phytoplankton, and micro scopic animals called zooplankton. Phytoplankton produce most of the food for an aquatic ecosystem. Nekton are free-swimming organisms, such as fish, turtles, and whales. Benthos are bottom-dwelling organisms, such as mussels, worms, and barnacles. Many benthic organisms live attached to hard surfaces. Decomposers, organisms that break down dead organisms, are also a type of aquatic organism.
1. How are organisms in an aquatic ecosystem grouped?