Plankton may be small in size, but they have an outsized impact on our lives. These teeny-tiny organisms are the basis of the ocean food chain. They are a major source of food for many of the world’s beloved sea creatures, from the majestic whale to colorful coral reefs and even the smallest of species living at the bottom of the food chain. In fact, plankton are the most abundant of all ocean creatures and are estimated to contribute some 50 percent to the photosynthetic production of Earth’s oceans. These microscopic organisms truly form the foundation of ocean ecosystems and can help scientists understand the health of our planet’s oceans. Plankton are made up of phytoplankton and zooplankton. Phytoplankton are autotrophic, meaning they can make their own food. They are tiny photosynthetic marine organisms that absorb energy from the sun and convert it into chemical energy through a process called photosynthesis. Phytoplankton also produce oxygen, which is then released from the ocean into the atmosphere. Zooplankton, on the other hand, are heterotrophs, meaning they cannot make their own food and must consume organic matter to survive. As such, zooplankton eat the phytoplankton, which creates a balance between the two types of organisms. Finally, plankton are so important for oceanic health because of the role they play in controlling the climate. It is estimated that plankton take in more than 150 million metric tons of carbon dioxide each year from the atmosphere and convert it either into organic compounds like carbohydrates or back into carbon dioxide, which is released as part of the plankton's respiration process. This effectively regulates the amount of carbon dioxide in the atmosphere and helps to maintain a balance in the Earth’s climate. As such, any change in the numbers and types of plankton can have a huge impact on the climate. For example, a decline in phytoplankton populations could result in a decrease in oxygen production, while an increase in temperatures could result in the growth of toxic algae blooms. These blooms can deplete the coastal waters of oxygen, destroying the habitats of sea creatures and negatively impacting the local economy. In conclusion, it is clear that plankton are some of the most important, yet overlooked, organisms on the planet. They play a key role in the ocean food chain, form the basis of ocean ecosystems, and help to regulate the global climate. Without these tiny creatures, life in the oceans would be very different indeed.