Plankton species can adapt to changing water temperatures, allowing them to swim efficiently even in colder, heavier water, according to a team of Texas researchers who recently published their results in the Proceedings of the National Academy of Sciences. That’s important because the tiny organisms are one of the most important food sources in the ocean’s food web. Even large animals like whales and some plankton-eating sharks depend on huge accumulations of these microscopic creatures to survive.
Jian Sheng, a mechanical engineer at Texas Tech, photographed moving plankton with 3-D holographic techniques developed in his own lab. “At 3,000 frames per second, it was like tracking a racecar through a microscope,” he explained.
The photo study was important because cold water is more viscous than warm water. As the climate becomes more extreme, some areas of ocean may get significantly cooler than in the past. For a tiny creature, it’s like swimming through honey would be for us. The researchers feared that plankton in chilled water would no longer be able to escape predators effectively, leading to a serious break in the food chain once all of them were eaten.
However, Sheng showed that the plankton could switch to using a more powerful swimming stroke to keep moving fast enough to escape predators.
Of course, the global challenge to the world’s marine food webs doesn’t just come from the bottom. There are many serious issues that are facing the higher ocean-going animals and birds, including charismatic marine mammals. Beached whales and even dolphins have been repeatedly found dead or dying, and the cause has been attributed to everything from eating plastic garbage to naval forces using loud sonar equipment.
Even though many whales eat plankton, the microscopic animals aren’t helped if they’re wiped out. Last year, Melissa Stusinski reported on how whale poop actually helps to fertilize the growth of plankton.
Maintaining the health of the world’s oceans is a balancing act. But the evidence that plankton can adapt to changing temperature can only be encouraging news.
[plankton-created sea foam photo courtesy Brocken Inaglory for Wikipedia Commons]