Jellyfish may be an annoyance for humans enjoying beach vacations, but they’re a vital element in the regulating the ocean’s temperature and nutrient balance.

CalTech bioengineer and 2010 MacArthur Fellowship recipient John Dabiri has been studying the biomechanics of jellyfish propulsion with an eye toward developing human modes of transportation that replicate the jellyfish’s simplicity and energy efficiency. On the way, he’s made observations that underscore the elegance and inter-connectedness of biological systems in the natural world.

Among them is the discovery that in their daily, cyclic treks from the bottom of the ocean to the surface, jellyfish transport and deliver huge volumes of cold, nutrient-rich water. The vortices they create by contracting their bodies and expelling water as they swim mix the nutrients throughout the various marine strata.

On the return trip, they move warmer, nutrient-depleted water from the surface back to the depths. In aggregate, the hundreds of millions of jellyfish play a crucial role in balancing oceanic temperatures. They’ve been serving this function for approximately 550 million years!

In a sense, they’re like red blood cells delivering oxygen from the lungs to the tissues, and then returning, in a never-ending rhythm.

So the next time you swim into one of these elegant, though admittedly nettlesome creatures, give it wide berth and know that it’s doing a very important job.

Dr. Dabiri’s work was highlighted in the October edition of National Geographic magazine.

Watch a clip of Dr. Dabiri talking about his work, with some beautiful images of jellyfish in action.