Dr. Eden Tekwa conducted the first research of its kind on Earth's living organisms and found that the smallest and largest organisms outweighed all others. This surprising pattern contradicts current assumptions that biomass would be distributed equally across all body sizes.
According to new UBC research, life comes in all shapes and sizes. Some sizes are more popular than others.
Dr. Eden Tekwa, who worked on the research as a postdoctoral fellow at UBC's department of zoology, examined all Earth's living organisms, and discovered an unexpected pattern. Contrary to what current theories can explain, our planet's biomass—the material that makes up all living organisms—is concentrated at either end of the size spectrum.
"This appears to be a new and emerging pattern that needs to be explained, and we don't have any strategies right now." According to current theories, biomass would be evenly distributed across all body sizes.
These findings have implications for predicting the effects and impacts of climate change. “We need to think about how body size biomass distribution will affect ecosystems under environmental pressures,” said Dr. Tekwa.
"Life constantly amazes us, especially the incredible breadth of sizes that it comes in," says senior author Dr. Malin Pinsky, an associate professor at Rutgers University's department of ecology, evolution, and natural resources. "If the tiniest microbe was the size of the period at the end of this sentence, the largest living organism, a sequoia tree, would be the size of the Panama Canal."
Dr. Tekwa spent five years compiling and analysing data on every type of living organism on the planet, from tiny one-celled organisms like soil archaea and bacteria to huge organisms like blue whales and sequoia trees. The same upper limits were observed in many species and environments.
“Trees, grasses, underground fungi, mangroves, corals, fish, and marine mammals all have similar maximum body sizes, which might indicate that ecological, evolutionary, or biophysical limitations exist.
Dr. Tekwa was able to gain insight into various ecosystems, including life. “Coralls are found to have about the same amount of biomass as all fish in the ocean,” said the author.
We already know that humans are a relatively small amount of matter, but our size among all living things reveals our place in the global biome. “We belong to the size range that comprises the highest amount of biomass, which is a relatively large body size,” said Dr. Tekwa.
Dr. Tekwa believes that their findings will help inform future investigations into Earth's evolving environment. "This allows us to go forward," they said. "For example, fish biomass is probably half of what it was before humans arrived, but it becomes harder and harder to infer those patterns as we go farther back in geological time.
Surprising Size Extremes Dominate Earth's Biomass.
Eden W. Tekwa, Katrina A. Catalano, Mary I. O'Connor, and Malin L. Pinsky, PLOS ONE, February 20, 2023. DOI: 10.1371/journal.pone.0283020
