CTD and POC flux in western North Pacific in July 2023

Here we present conductivity–temperature–depth (CTD) data, chlorophyll-a (Chl-a) profiles, particulate organic carbon (POC) fluxes, and stable carbon isotope (δ¹³C) compositions from five stations (P1–P5) in the low-latitude western North Pacific (6–13°N, 131.98–134.99°E). Data were collected during July–August 2023 aboard R/V Legend. The CTD system was a Sea-Bird Electronics SBE 9 equipped with a WETStar fluorometer. POC concentrations were determined using a Vario EL Cube elemental analyzer. POC fluxes were calculated from samples collected by floating sediment traps. Stable carbon isotope (δ¹³C) compositions of POC in floating-trap samples were analyzed with a continuous-flow isotope-ratio mass spectrometer (MAT253, Thermo Finnigan, San Jose, CA, USA) coupled to an elemental analyzer (EA1108, Carlo Erba Instruments) via a Conflo III interface (Thermo Finnigan, San Jose, CA, USA).