Plankton are microscopic marine plants that float in the upper part of the ocean where sunlight penetrates the water. Plankton are responsible for half of the world's photosynthesis. These small plants require inorganic nutrients to survive, which they get from colder ocean currents that rise from the sea floor.When too many nutrients reach these tiny plants, populations explode and harmful algae blooms form. These masses of plant life produce toxic compounds that harm fish, birds, mammals, shellfish and even humans. When the delicate balance of plankton is disturbed, many larger creatures are affected.Plankton remove approximately 100 million tons of carbon dioxide from the Earth on a daily basis, reducing greenhouse gases that make the planet warmer. Plankton populations are indicators that let scientists know if oceans are changing. Biologists have noted that as oceans get warmer, plankton distribution decreases and animals must shift their migration patterns to follow their food. Fish populations that once thrived in certain areas move to where plankton migrate, altering larger sea creatures' habits and changing the fishing industry.
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