A02-4 Ocean circulation and biological production/decomposition in the CO2 uptake hotspot
Home > Members > A02-4 Ocean circulation and biological production/decomposition in the CO2 uptake hotspot
A02-4
Principal Investigator
TOYAMA Katsuya
Meteorological Research Institute
Co-Investigators
HASHIHAMA Fuminori
Tokyo University of Marine Science and Technology
NAGAI Takeyoshi
Tokyo University of Marine Science and Technology
OKA Eitarou
U. Tokyo
HOSODA Shigeki
JAMSTEC
Postdoctoral Researcher
Research Collaborators
KODAMA Taketoshi
U. Tokyo, Co-I of A03-7
KOMATSU Kosei
U. Tokyo, Co-I of A03-7
YAMAGUCHI Ryohei
JAMSTEC, , Co-I of A01-1
HAYASHIDA Hakase
JAMSTEC, , Co-I of A02-6
TAKETANI Fumikazu
JAMSTEC, , Co-I of A02-5
UCHIDA Hiroshi
JAMSTEC
SATO Kanako
JAMSTEC
KOSUGI Naohiro
Meteorological Research Institute
ISHII Masao
Meteorological Research Institute
ONO Hisashi
Japan Meteorological Agency
KOJIMA Atsushi
Japan Meteorological Agency
TSUZUKI Takato
Japan Meteorological Agency
SASANO Daisuke
Japan Meteorological Agency
KATSURA Shota
Tohoku U.
TAMURA Saori
Tokyo University of Marine Science and Technology
Both biological production of organic carbon in the sunlit surface layer of the ocean and bacterial decomposition of the organic carbon in the surface layer and twilight zone (also known as “mesopelagic” layer) just below it are fundamental components of the Earth system controlling the air-sea CO2 exchange and availability of marine biological resources, as ocean circulation is. Their detailed description and mechanistic understanding, however, are lacking due to very limited availability of historical shipboard observation data of the ocean interior with sufficient spatio-temporal resolution.
In this project, we will deploy five profiling floats equipped with CTD (temperature, conductivity and pressure) and some biogeochemical sensors and conduct high-resolution physical/biogeochemical survey in the Kuroshio-Oyashio extension region, which is a “hotspot” of oceanic CO2 uptake. Out of the five floats, three floats are equipped with dissolved oxygen, pH, chlorophyll fluorescence and backscatter sensors, another one with dissolved oxygen sensor, and the other one with dissolved oxygen, chlorophyll fluorescence and backscatter sensors as well as turbulent profiler.
Shipboard observations of the same region will also be conducted to obtain high-quality measurements of a suite of physical/biogeochemical parameters including nutrients and turbulence. These observations will include cross-sectional surveys along 141.5E meridian by Shioji-maru, a training vessel of Tokyo University of Marine Science and Technology, and along 137E meridian by Ryofu-maru and Keifu-maru, research vessels of Japan Meteorological Agency.【In collaboration with A02-5 and A03-7】
Based on these complementary observations by floats and ships, this project describes in detail the seasonal variability and vertical distribution of biological production/decomposition. The mechanism of nutrient supply necessary for sustaining the production in the surface layer is further examined by synthetically considering contributing components such as air-sea exchange of biogeochemical elements (e.g. nutrient deposition) and transports by ocean currents.【in collaboration with A01-1, A02-5 and A03-7】
This project also aims at evaluating how well the carbon cycle models and Earth system models represent the processes of biological production/decomposition and air-sea CO2 gas exchange against the observation and improving the representation of these processes in the models. We also aim to advance biogeochemical data assimilation techniques.【in collaboration with A02-6】
This project will be pushed forward in collaboration with some external projects and institutes such as the CREST Carbon-Blue X project “Elucidation of CO2 absorption and storage mechanism of subtropical mode water by Argo” and the Advanced Institute for Marine Ecosystem Change (WPI-AIMEC) of Tohoku University and JAMSTEC.
