Tiny science update: Clouds and microbes


Electron microscopy image of a single cell of the ocean plankton species Emiliania huxleyi. The lacy-looking panels on its surface–called coccoliths (“seed-stones”)–are made of calcium carbonate (limescale). When the organism dies, these hard scales are shed into the water. By Alison R. Taylor (University of North Carolina Wilmington Microscopy Facility) (PLoS Biology, June 2011, Cover ([1])) [CC BY 2.5 (https://creativecommons.org/licenses/by/2.5)%5D, via Wikimedia Commons

In one of my very first blog posts on this site (“Raindrops keep falling on our heads…and on the microbes“) I shared some science news I had seen about microorganisms and clouds. Scientists across different disciplines are trying to learn about the relationship between the planet’s water cycles and the growth of tiny organisms (such as bacteria and fungi)–and how aerosols of microscopic life could seed the clouds themselves. I’d never heard of this topic before reading about it last year. The idea that living things can influence the weather and their own life cycles in different ways through their dispersion in the atmosphere is fascinating to me. And so when a beautiful image like the one on the right caught my eye last week, with the headline “Viruses may help phytoplankton make clouds–by tearing algae apart,” by Carolyn Gramling in ScienceNews, I was happy to see a new update on the story of clouds and microorganisms.

I’m going to quote Gramling’s opening line from the article, because I think it is a great example of engaging science writing: “When tiny sea algae get sick, they may sneeze the seeds of clouds.” How amazing is that idea? When people get infected by viruses, such as the adenovirus that causes the common cold, we may sneeze and spread the virus to another person. When this tiny phytoplankton species is infected with a virus, the cell dies. But the virus also causes the dying cell to rapidly drop its tiny calcium carbonate plates off the outside. (Perhaps this helps the virus spread more easily to other cells, which shed and grow the plates more slowly). Scientists think that the dispersion of these little plates of limescale in the oceans become part of a collection of microscopic particles that can get transferred to the air as aerosols in the sea spray. What role these calcium carbonate flakes have in cloud formation is still unclear. Maybe they help assemble water droplets, or impact the chemistry of the process. Or maybe they hinder cloud formation through interaction with other particles. No one really knows yet. But the latest finding by Miri Trainec and collaborators at the Weizmann Institute of Science in Israel and elsewhere about how viruses can impact these dynamics is yet another piece of the puzzle that scientists didn’t know about before.


Phytoplankton bloom in the North Sea, appearing as light blue against the ocean’s deep blue-green. How might these algae affect cloud formation? How does cloud cover affect local weather and global climate? Scientists are still working to figure it all out. By Jeff Schmaltz (NASA Earth Observatory) [Public domain], via Wikimedia Commons 

When I read a little more background on this topic, I learned about some of the earlier research into algae and cloud formation. In 2015, Daniel McCoy at the University of Washington and collaborators studied cloud formation in the Southern Ocean, where they identified a correlation in changes in cloud cover with seasonal growth of marine life, including algae and other phytoplankton. Algae are known to grow more when nutrients or temperatures increase. If their population increases rapidly, it can lead to algal blooms, like the toxic Red Tide that is currently causing problems for people and marine wildlife along the Gulf Coast of Florida, causing Florida’s governor to declare a state of emergency. The phytoplankton in the current study also can create blooms. The impact of carbon storage and release during algal blooms is being studied in addition to the cloud formation parameters. As our climate changes and areas of the ocean change temperature, acidity, and composition, it will be increasingly important to understand the interplay between the geologic process in the atmosphere and the living systems in the oceans that are using Earth’s raw materials in their life cycles.


I noticed a little science tidbit about graceful-looking microbes only in the periphery of my daily news feeds on social media this week. The story of the plankton, though, shows the incremental pace of new scientific discovery, and the unexpected ways in which new findings can improve our understanding of big questions about our world. It also has piqued my curiosity about a topic I knew very little about, and builds on my appreciation of the cloud/microbe connection that I started reading about last year. Thanks to the science writers who brought the story to life, and to the scientists working on interesting questions! I’ll keep my eyes open for the next installment.

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