JpGU-AGU Joint Meeting 2020

Presentation information

[E] Poster

A (Atmospheric and Hydrospheric Sciences ) » A-OS Ocean Sciences & Ocean Environment

[A-OS19] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

convener:Takafumi Hirata(Arctic Research Center, Hokkaido University), Shin-ichi Ito(Atmosphere and Ocean Research Institute, The University of Tokyo), Enrique N Curchitser(Rutgers University New Brunswick), Eileen E Hofmann(Old Dominion University)

[AOS19-P09] Effects of the Kuroshio meander on phytoplankton in Japanese waters as observed by satellite remote sensing

Satoshi Kitaoka2, *Takafumi Hirata1, Keiko Sato1 (1.Arctic Research Center, Hokkaido University, 2.Faculty of Environmental Earth Science)

Keywords:Kuroshio, phytoplankton, meander, remote sensing

The Kuroshio current is one of the western boundary currents and known as a thermal energy transporter from low latitudes to to mid-latitudes in the Western Pacific. On the other hand, the Kuroshio is also a unique western boundary current in that it causes a large meander. Indeed, the meander has occurred in 2017 and is still continuing (at the time of writing). In ecological perspective, the Kuroshio is characterized as a carrier of oligotrophic seawater. In spite of the oligotrophy, the Kuroshio water is known for spawning and feeding grounds of commercial/non-commercial fish larvae, explaining a higher fisheries production in the region. Thus, it currently puzzles an ecological representation of the Kuroshio water in that a relationship among nutrient fields, standing stock and productivity of organisms are not well understood. In order to better understand the Kuroshio ecosystems, phytoplankton dynamics, a lower-trophic organism, is investigated using remote sensing data of phytoplankton chlorophyll-a pigment and of phytoplankton community structure inferred from the pigment. Especially time series analysis was conducted to identify temporal scales of their variability from daily scale to decadal scale, thanks to the high-frequency observation by the Advanced Himawari Imager, AHI, and to the long-term observation by the Moderate Resolution Imaging Spectroradiometer, MODIS. In this presentation, we discuss how the temporal variability of different phytoplankton groups (as well as the total phytoplankton community) in the Kuroshio and adjacent waters are affected by the large meander of the Kuroshio occurring since 2017.