An ecosystem of tiny, cold-resistant phytoplankton living beneath the surface of icy waters near the north pole plays an integral role in the planet’s carbon cycle. And NASA is shooting giant freakin’ laser beams at it.
The tiny plants exist in a fluctuating “boom and bust” life cycle. The laser experiment recently found that even small environmental changes could heavily influence the cycles, which is a huge deal, because the tiny phytoplankton represent the base-level of the entire coastal and oceanic ecosystem’s fragile food web. Oh, and they also suck carbon dioxide out of the atmosphere through photosynthesis. Essentially, if they die, we could all die.
“It’s really important for us to understand what controls these boom-and-bust cycles, and how they might change in the future so we can better evaluate the implications on all other parts of the food web,” Michael Behrenfeld, a marine plankton expert at Oregon State University in Corvallis said.
Typically, NASA and other oceanographic or conservation organizations study phytoplankton levels by measuring light that reflects off of the ocean plants with various satellite sensors. But those sensors don’t work for crap in polar regions, where dark skies and constant cloud cover limit the light that the satellites can pick up. So NASA decided to bring its own light in 2006 — the Cloud-Aerosol Lidar with Orthogonal Polarization, or CALIOP, that is, yep, essentially a giant laser beam coming out of a satellite (called CALIPSO), which looks like this:
If CALIOP sounds familiar, it’s because the technology it uses, LIDAR, is one of the most common systems used to help self-driving cars navigate.
“CALIOP was a game-changer in our thinking about ocean remote sensing from space,” Chris Hostetler, a research scientist at Langley said. “We were able to study the workings of the high-latitude ocean ecosystem during times of year when we were previously completely blind.”
CALIPSO, the satellite that carries CALIOP, launched in 2006, so the current results come off of nearly a decade of data. The takeaway is that as global warming tears through the polar ice caps, the ecosystem of phytoplankton is going to change as well. The plankton’s boom and bust cycle, as researchers described it, has an effect on every species in their ecosystem.
The new results found that boom cycles only last as long as the plankton’s growth rate is accelerating — meaning as soon as their growth rate becomes stagnant, the whole web of predators behind them in the food chain quickly catch up, ending the boom, and causing a “bust.” Once the plankton are gone, the larger chain starts to die off again too, to regulate. But in polar regions around Antarctica, the boom and bust cycles were tied to the ice cap coverage, not to year-to-year growth rates — which means as the ice dies, so too does the ocean ecosystem.
“The take-home message is that if we want to understand the biological food web and production of the polar systems as a whole, we have to focus both on changes in ice cover and changes in the ecosystems that regulate this delicate balance between predators and prey,” Behrenfeld said.
Photos via NASA/Timothy Marvel, NOAA