Phytoplankton, a type of microscopic organism, take in carbon dioxide and convert it into organic carbon through photosynthesis, like plants. Each year, this process moves many tens of billions of tons of carbon through the sunlit surface ocean and contributes to the oxygen in the air we breathe. These massive natural carbon flows highlight the central role the surface ocean plays in regulating Earth’s carbon cycle. “For this study, we placed six phytoplankton species representing major groups of marine phytoplankton under controlled conditions. They had the nutrients and light they needed to grow,” said Yuting Zhu, co-lead author of the study and former WHOI postdoctoral investigator, now with Old Dominion University.…