Phytoplankton - tiny plant-like organisms drifting through the great, vast ocean - are barely visible to the naked eye, and some are visible only through a microscope. Yet, when they are thriving, it is possible to see them from as far away as space. Their location is marked by swirling patterns of bright blues and greens that give the ocean a slick, marbled appearance, like oil on water.
Researchers Trish Quinn and Tim Bates of NOAA's Pacific Marine Environmental Laboratory, are interested in understanding how phytoplankton leave their mark on the climate system. For decades, Earth scientists have hypothesized that, in addition to being the cornerstone of the ocean food web, chemicals released by phytoplankton are responsible for allowing clouds to form over the open ocean.
Because clouds play a huge role in how much sunlight reaches and warms the Earth's surface, scientists thought phytoplankton's contribution to cloud formation was a critical part of the climate system. Proposed in the 1980s, it was an elegant hypothesis that reflected scientists' growing awareness of how intimately one part of the Earth system could be connected to another.
But after looking at two decades of observations and computer simulations, Quinn and Bates concluded that the role of phytoplankton emissions is much smaller than originally thought, and therefore, does not have a significant part in counteracting climate change. These results indicate that it is time to retire the CLAW hypothesis.
CPO's Earth System Science grants program, specifically the Atmospheric Chemistry, Carbon Cycle, & Climate (AC4)
program, provided support for this study. Continue reading this month's OAR Spotlight story on the NOAA Research website.