Award: OCE-1536346

Phosphorus is an essential element for all living things, including marine plankton. This is because phosphorus is utilized to make DNA and other molecules, which all living things need in order to grow. The phosphorus is these molecules is in a form termed "V" phosphorus after the roman numeral for the number 5. However, over the last few years, numerous lines of chemical and genetic information have emerged to show that molecules containing phosphorus in the "III" form are also present in the ocean. This is particularly true in offshore areas such as the Sargasso Sea, which is in the Atlantic Ocean about 100 miles off the coast of the Carolinas, Georgia, and Florida. There is so little phosphorus V in the Sargasso Sea, that plankton struggle to survive. Yet we did not know if utilizing phosphorus III is something that helps struggling plankton. We wondered, which plankton make phosphorus III molecules? When, where, why, and how do they make them? These are all tough questions, but we made substantial progress toward answering them. We went on two research cruises between the Sargasso Sea and the east coast of the U.S., sampling the plankton along the way and taking them back to the laboratory for chemical analysis. Our data showed us something unexpected: the phosphorus III molecules were more important in waters right off of our coast. These strange and unknown molecules may be made by some of the smallest plankton in the ocean. Interestingly, these plankton made more phosphorus III molecules when there was more phosphorus V available in the water. Since agriculture and other processes are leading to more phosphorus being delivered to the ocean from rivers, it is possible that these phosphorus III molecules will become even more important. In fact, the most important herbicides used on farms contain phosphorus in the III form. Since phosphorus is so important for all living things, we need to know more about the roles that phosphorus III and V play in the oceans off our coasts. Last Modified: 06/03/2019 Submitted by: Benjamin Van Mooy