A-line Oceanographic Data

Hokkaido National Fisheries Research Institute (HNF) and Tohoku National Fisheries Research Institute (TNFRI) made a repeat hydrographic section across the Oyashio off the Hokkaido Island, Japan in 1987. Physical oceanographic observation started 1987 and chemical/biological measurement followed from 1990. Hydrographic observations have been operated 98-times almost bimonthly from January 1988 to Mar. 2003 along this section, which is called "A-line" after the name of the Akkeshi-town near the starting point of this line. Observations are still ongoing, and monitoring parameter consists of CTD data from surface down to 3000m, bottle salinity, nutrients and Chlorophyll-a data from surface to 200m depth (or 3000m depth after 2002 except for Chlorophyll-a). Net-plankton biomass had also been observed with various gears, and various other biogeochemical parameters such as DIC, alkalinity, POC/N, DOC/N, iron concentrations, biogenic silica, phytoplankton/zooplankton species composition, microzooplankton, bacteria abundance, water optical properties, and primary production are also measured along A-line at certain period in collaboration with other institutes and universities. Deposited content: descriptive metadata only; underlying research data are not included.