It is said that size doesn’t matter, and this is also true for the tiny plankton species. These organisms float freely in the oceans and serve as the foundation for marine food chains. These small creatures can influence weather patterns and, over time, alter the climate in ways that benefit them.
When solar energy becomes too intense, plankton create clouds.
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| Plankton can influence weather and create clouds (Photo: alles) |
It may sound unbelievable, but recent studies funded by NASA have confirmed an old hypothesis that plankton can indirectly create clouds to block harmful radiation from the sun. The research was conducted by Dierdre Toole from the Woods Hole Oceanographic Institution (WHOI) and David Siegel from the University of California, Santa Barbara (UCSB).
The study showed that in summer, when sunlight penetrates the surface waters of the ocean where plankton live, harmful ultraviolet (UV) rays negatively impact these organisms, which are also responsible for sunburn in humans.
When plankton are affected or stressed by UV rays, biochemical changes occur in them.
Plankton attempt to protect themselves by producing a chemical compound called DMSP, which scientists believe helps stabilize their cell membranes. This chemical is broken down in water by bacteria, transforming into another substance known as DMS.
DMS escapes from the ocean into the atmosphere and continues to break down into tiny particles resembling dust. These particles are just the right size to attract water vapor, initiating the formation of clouds. Thus, indirectly, plankton help create more clouds; more clouds mean less direct sunlight reaching the ocean’s surface. This reduces stress on these organisms by lowering harmful UV rays.
Most DMS is produced from June to September. Interestingly, this is also the period when plankton populations decrease to their lowest levels. This demonstrates that the quantity of plankton does not affect the amount of DMS they produce. The research found that throughout the summer, up to 77% of changes in DMS levels are directly related to UV radiation. Researchers were surprised that such a single factor could have such a significant impact on this process.
Siegel commented: “For those studying marine biology and ecology, it is hard to fully trust such dramatic changes.”
Researchers were also astonished to find that DMS molecules can refresh themselves every three to five days. This means that plankton can respond to UV rays quickly enough to impact their own weather conditions. Toole and Siegel were amazed by the rapid turnover rate of DMS.
The next step for the researchers will be to assess how these clouds actually affect climate change. By clarifying the response mechanisms of plankton to light, scientists now have the necessary information to build mathematical models to calculate the impact of plankton on cloud formation. Because white clouds can reflect sunlight back into space, scientists believe that clouds generated by plankton may have certain effects on global temperatures.
This research has been funded by NASA, while studies on DMS have been supported by the National Science Foundation.
