Phytoplankton are a species of microalgae that dwell in water. They are photosynthetic organisms that depend on sunlight and nutrients like carbon dioxide to increase in energy and flourish.
“Phytoplankton under a microscope” by Seth Benson, USGS Great Lakes Science Center
Different types of phytoplankton include: diatoms, coccolithophores, dinoflagellates, silicoflagellates, green algae, and cyanobacteria. They vary in shape, and some have a tail-like body part, called “flagella” to help navigate waters, while those without the appendage let the movement of the ocean relocate them.
The Role and Effect of Phytoplankton
Most of the carbon dioxide that is transferred from the atmosphere to the ocean is absorbed by phytoplankton and released when they decompose. In addition to influencing the levels of carbon dioxide in the sea, they also serve a crucial role in the aquatic food chain, being a primary source of food for a wide range of marine organisms and animals.
During the spring and summertime, nutrients from swirling and mixing waters during the winter calms and warmth increases from the sun, causing phytoplankton to grow at a fast rate. This occurrence is called a “bloom”.
“Phytoplankton bloom in Lake Ontario” by Jeff Schmaltz, NASA/GSFC/MODIS Land Rapid Response Team
Blooms can be observed by looking at chlorophyll levels in the ocean on a distribution map. The more green an area, the more chlorophyll, which also signifies phytoplankton.
The Carbon Cycle and their Involvement
Phytoplankton heavily influence climate change and biodiversity. It has been observed by researchers that warmer waters caused by an increasing amount of greenhouse gas in the atmosphere will lead to more decreases in nutrient recycling and thus, less phytoplankton.
This type of microalgae is important, existing as a primary source of food for other aquatic organisms like zooplankton, as well as a source of life for all living creatures, as they are main contributors to the carbon cycle, through their consumption of carbon dioxide and release of oxygen into the environment.
If you would like to learn more about the current state of phytoplankton, and explore their presence in waters around the world based on chlorophyll concentration, see NASA’s Global Phytoplankton Distribution Story Map.
Written by Miette Broussard
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