What is phytoplankton's role in aquatic ecosystems?

Phytoplankton plays a crucial role in aquatic ecosystems as primary producers. They are microscopic plant-like organisms that perform photosynthesis, using sunlight to convert carbon dioxide and nutrients into organic matter. This process not only produces oxygen, which is essential for most aquatic life, but also forms the base of the marine and freshwater food webs.

As primary producers, phytoplankton provide the foundational energy source for a wide array of aquatic organisms, including zooplankton, which feed on them, and larger fish that subsequently consume those zooplankton. Thus, they are integral to supporting higher trophic levels in aquatic ecosystems, facilitating energy transfer throughout the food web. The abundance and productivity of phytoplankton can significantly influence the health, diversity, and overall dynamics of aquatic environments.