2026-07-16T17:25:49Zhttps://pdr.repo.nii.ac.jp/?action=repository_oaipmh

oai:pdr.repo.nii.ac.jp:000000502026-01-06T01:33:08Z00019

engSouthern OceanChlorophyll amacronutrientshttp://id.nii.ac.jp/1434/00000035/info:doi/10.20575/00000035Journal ArticleThe chlorophyll a concentration is the most commonly used indicator of phytoplankton biomass, which is regulated by macronutrients and light intensity. Long-term monitoring of chlorophyll a provides basic information on the ecosystem changes associated with climate change. As part of the monitoring program of the Japanese Antarctic Research Expedition (JARE), the chlorophyll a concentration and macronutrients (nitrate, nitrite, phosphate and silicic acid) have been measured by the icebreakers Fuji and Shirase since JARE-14 (1972/73) and JARE-7 (1965/66), respectively, and during the cruise of the training vessel (T/V) Umitaka-maru, of Tokyo University of Marine Science and Technology, since JARE-55 (2013/14). The Umitaka-maru follows almost the same course every year; after leaving Fremantle, it travels to the sea ice edge (ca. 65°S) along the 110°E meridian and then returns to Hobart. Its course covers waters in the Southern Ocean that range from sub-tropical to polar. During the cruise, water samples for determining chlorophyll a and macronutrient concentrations are obtained from an underway pump twice a day, and photosynthetically active radiation is measured continuously by a sensor mounted on the bridge of the ship. Vertical water sampling to determine the chlorophyll a concentration is conducted at six stations along the 110°E meridian, and the macronutrient concentrations at the same stations are determined by another monitoring program. This report includes the latest data collected during the T/V Umitaka-maru cruise in the 2019/20 season. In 2019/20, three vertical sampling stations (KC7-9) were added to enhance the bottom water monitoring performed under the “Physical and Chemical Oceanography” routine observation program of the JARE.Polar Data Journal69162022-04National Institute of Polar Research2432-6771https://doi.org/10.17592/001.2021040702publisherhttps://pdr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=50&item_no=1&attribute_id=22&file_no=1CC BYhttps://pdr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=50&item_no=1&attribute_id=22&file_no=2© 2022 National Institute of Polar Researchhttps://pdr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=50&item_no=1&attribute_id=22&file_no=3© 2022 National Institute of Polar ResearchMarine biology2022-04-11