plancton
Plankton are tiny organisms that drift in oceans, rivers, and lakes. They are a crucial part of aquatic ecosystems, serving as the primary food source for many marine animals, including fish and whales. Plankton can be divided into two main types: phytoplankton, which are plant-like and perform photosynthesis, and zooplankton, which are small animals that feed on phytoplankton and other small organisms.
These organisms play a vital role in the Earth's carbon cycle by absorbing carbon dioxide and producing oxygen. Plankton populations can vary greatly depending on environmental conditions, such as temperature and nutrient availability, making them important indicators of ecosystem health.