By: Frank M眉ller-Karger, USF Distinguished University Professor
Frank M眉ller-Karger is a Distinguished University Professor at the USF College of Marine Science.
Plankton are not organisms we think about all the time, and yet they are all around us in every drop of water, every river, our coasts, and everywhere in the ocean. They are the 鈥渄rifters鈥� of our planet.
Our lives are completely intertwined with the lives and cycles of these plants, algae, and animals. Many of them are microscopic but the plankton scales from microscopic to lengths of some 150 feet. Some live just hours, but many live for many years. They grow in a huge array of shapes and colors, and many of them change form as they reproduce and age, from larval stages to fully grown adults, including corals, starfish, urchins, crabs, krill, fish, and algae. Even turtles and whales are considered plankton if they are just carried around by currents. The biodiversity of plankton is fantastic, and their functions in aquatic ecosystems are even more amazing.
Plankton are the base of the food web. They consume and produce oxygen, carbon dioxide, and many other compounds. They are part of the mechanisms by which carbon and energy move in the ocean, and so are a pathway of transport of carbon from the ocean surface to the deep ocean, where it can be stored for hundreds to thousands of years. Plankton are a big factor in maintaining good water quality but are also an indicator of bad water quality.
led by Maria Grigoratou, Executive Secretary of the European Polar Board, in collaboration with marine scientists at the USF College of Marine Science and other international experts, lays out the benefits and value that plankton provide to people. Published in Bioscience, the open-access article lays bare 鈥榯he immeasurable value of plankton to humanity鈥� across six themes: biogeochemistry; ecology; climate; evolution of science; economy; and culture, recreation, and well-being.
I have worked on plankton for my entire professional life. For over 40 years, I have collected samples of plant-like (phytoplankton) and animal plankton (zooplankton) from the ice in the Arctic, coastal zones, estuaries, and the middle of the ocean. I have measured how much and how fast plankton and their remains settle from the surface to depths of over 10,000 feet in different parts of the ocean. Using sensors that measure the color of the ocean on satellites launched into space by NASA, NOAA, and other agencies around the world, I鈥檝e measured how fast plankton grow and how they disperse across large ocean distances. Now, as one of the leaders of the , or MBON, I鈥檓 collaborating with people across the country and the world to quantify the biodiversity of plankton.
It is becoming more and more clear that the ecology of the entire ocean, and our own well-being, are tied to the biodiversity of plankton. Many scientists still just measure plankton in units of weight or concentration of organic carbon, or of inorganic carbon like chalk. But the thing is that the different types, species, and sizes of plankton drive very different parts of the food web, of the carbon cycle, and of the cycle of many minerals that are of interest to us. This is what ultimately make life possible. Ourselves we don鈥檛 really think of life as just a bunch of carbon 鈥� when we think of a meal, we see steaks and salad, and fish and chips, as very different. We recognize differences in people, and don鈥檛 just see them as a bunch of carbon. This biodiversity is the unique thing about Earth compared to other planets, and the plankton carries out functions that make our own life and much of our commerce possible.
To look at the value of plankton, we used the convening power of the MBON to bring together experts together from around the world. This included people that are making computer models of plankton and people that look at plankton in the traditional way: through microscopes, to identify their taxonomy. We brought people that measure their genetic biodiversity, and people that design sensors to launch into space to measure plankton biodiversity and concentrations across the entire world ocean by measuring the color of water. The experts organized and started meeting virtually during the COVID-19 years, and have continued to meet.
IMAGE ABOVE: This is one of many detailed infographics featured in the new paper that looks into the value of plankton. Credit: Mercator Ocean 2025.
Our goal is to see how we can improve our understanding of life in aquatic environments, and ultimately how to better forecast life using computer models. We want this capability just to make better decisions about water quality and providing food 鈥� just like we are now able to forecast weather.
This paper came about because we realized that, even among us, the value and benefits of plankton to societies everywhere are not apparent 鈥� and now we have a better sense for this value.
Read the full article, .