Altabet 9525937 This proposal will address a fundamental problem in biological oceanography from the viewpoint that vertically migrating algal mats in the open ocean are instrumental in redistributing nitrogen within the surface waters of the North Pacific Ocean. Using previously funded shiptime, the project will document Rhizosolenia mat vertical distribution throughout the upper 100-300 m, the quantitative N inputs, and potential for NO3- release in the surface layers by mats in the central North Pacific gyre. The research will characterize depth of origin, migration times and absolute transport rates by these macroscopic associations and determine if NO3- released by mat decay is taken up by other ambient phytoplankton. In addition, the study will survey other phytoplankton that may be vertical migrators such as Ethmodiscus, Pyrocystis, Halosphaera and solitary Rhizosolenia to determine if they are also important components of this process. At the conclusion of the study, the project will have examined waters of the central North Pacific gyre both east and west of Hawaii. This should lead to a broad spatial understanding of the importance of phytoplankton vertical migration in the oceanic waters of the North Pacific gyre.
