The many species of phytoplankton are all on the bottom of the food chain. They are the foundation of the marine food chain, according to NASA Earth Observatory. Many species of small fish and a few species of whales depend on phytoplankton for food. Larger fish eat the smaller fish and we humans or other animals eat those larger fish, completing the food chain.
Science Daily claims that phytoplankton have been influencing the global climate in a subtle way. Phytoplankton inhabits around ¾ of the Earth's surface, which has had a fundamental warming effect. The phytoplankton in the Earth's water supply absorbs a certain level of the sun's radiation which has had a slight effect on global temperatures. Phytoplankton has caused global temperatures to rise between 0.1 and 0.6 degrees F, according to Science Daily.
Scientists debate whether or not fertilizing the oceans with increased numbers of phytoplankton can be beneficial in reducing global warming. According to Science Daily, this theory poses that the phytoplankton would draw more carbon dioxide out of the atmosphere and reduce global warming. However, more phytoplankton would raise the temperature of our oceans because of the increased radiation absorption.
The phytoplankton in our oceans absorbs carbon dioxide from the atmosphere. When phytoplankton die, some of the carbon dioxide that they absorbed is released back into the atmosphere in a process called “remineralization” according to Environmental Science Published for Everybody Round the Earth (ESPERE). Photosynthesis leads to biomass formation while remineralization leads to the destruction of biomass.
Phytoplankton are one-celled organisms that float along the surface of the world's oceans. Phytoplankton are green because of their chlorophyll content, according to NASA Earth Observatory. Even under the most optimal conditions, a phytoplankton only lives for about a day or so before it dies and sinks to the bottom of the ocean.