What are Phytoplankton?

Originating from the Greek words phyto meaning plant and plankton meaning made to wander or drift; phytoplanktons are microorganisms, which survive in watery environments including salty and fresh waters.

phytoplanktonSome of the phytoplanktons are bacteria, while others are protists. Most of these microbes are single-celled plants. The common species amongst these are cyanobacteria, silica-encased diatoms, the dinoflagellates, green algae, and the chalk-coated coccolithophores.
Similar to plants found on the land, the phytoplankton has chlorophyll that is used to capture sunlight and uses photosynthesis to turn the sunlight to chemical energy. The microbes consume carbon dioxide while releasing oxygen. All species of the phytoplankton use photosynthesis; however, some of the species receive extra energy from the consumption of other organisms.

The growth of these microorganisms is dependent on the carbon dioxide, sunlight, and nutrients available. Just as plants found on land, the phytoplanktons require nutrients, which include nitrates, phosphates, silicate, and calcium in different amounts that depends on the specific kind of the phytoplankton. Some of the phytoplanktons can fix nitrogen and survive in locations that are low in nitrates. In addition, these microbes require iron, which is a limitation in growing phytoplankton in the vast ocean waters because the iron in the water is at very low levels. Other factors determine the growth of phytoplanktons. These include water temperature, the saline content, and depth of the water, wind conditions, and the types of predators that graze on these.

Under the right conditions, phytoplankton can grow abundantly, which is a phenomenon called as bloom. Oceanic blooms may be spread over several hundred square kilometers and can be viewed easily through the satellite images. Although, a bloom can last for many weeks, the life span of the individual phytoplankton is only a few days.