DOI: 10.26008/1912/bco-dmo.907028.1
title: CTD-associated variables, bottle salinity measurements, oxygen titrations, nutrient analyses, biogeochemical/biological variables, and DIC/Freon chemistry variables from R/V Roger Revelle cruise RR2004 along the 150W meridian from 30S to 60S

description: These data are part of the NSF project &quot;Collaborative Research: Biogeochemical and Physical Conditioning of Sub-Antarctic Mode Water in the Southern Ocean&quot;. Specifically, these are the discrete bottle data from cruise RR2004 aboard R/V Roger Revelle, which sailed from Honolulu, Hawaii on 26 December 2020 to the Southern Ocean and returned to Honolulu on 23 February 2021. The purpose of the project was to define the processes that condition Sub-Antarctic Mode Water (SAMW) formed at the Sub-Antarctic Front in the Southern Ocean. The cruise track was from 30 degrees South to 60 degrees South along the 150 degrees West meridian as well as an investigation of frontal boundaries and eddies further east (from 45S to 57S by ~145W). Bottle data were collected from CTD casts with tripped Niskin bottles on the CTD Rosette. Trace-metal-clean casts were performed using Niskin-X bottles suspended on Kevlar line and a trace-metal-clean block.  

The data reported herein fall into several categories, A) CTD-associated variables, B) bottle salinity measurements, C) oxygen titrations and nutrient analyses, biogeochemical/biological variables, and D) DIC/Freon chemistry variables. Regarding the specific data, we first report CTD variables (salinity, temperature, potential temperature, density, dissolved oxygen, sound velocity, pressure,  depth,  conductivity,   SeaBird-probe-derived oxygen concentrations, chlorophyll fluorescence, beam transmittance (660nm; %), backscattering, CTD PAR, and surface PAR reference.    Next, results from bottle samples for salinity, lab oxygen titration, and nutrient concentrations (nitrate, phosphate, silicate, nitrite, and ammonium). The following biogeochemical and biological variables are presented: particulate organic carbon concentration (POC), particulate organic nitrogen (PON), and particulate inorganic carbon (PIC), concentration of detached coccoliths (given as birefringent singlets, doublets, triplets, or quadruplets, when viewed in a compound microscope with polarization optics), total coccolith concentration (the sum of singlets, doublets, triplets or quadruplets), concentration of birefringent plated coccolithophore cells, coccospheres or coccolith aggregates, planar area subtended by detached coccoliths or plated cells, concentration of biogenic silica, concentration of chlorophyll, phaeopigment and their sum. There are a suite of variables from FlowCAM measurements, mostly done on particles greater than 5 micrometers (um) in diameter: Particle size distribution function (PSDF) slope, standard error of PSDF slope, Y-intercept of the PSDF, R^2 of the PDF slope, F statistic of PSDF slope, total cell concentration per milliliter (mL), concentrations (in cells per mL) of small 0-4um diameter cells, 4-12um round cells, 4-12um diameter ovoid cells, dinoflagellates, ciliates, diatoms silicoflagellates, other unidentified cells, followed by percent of total cell concentrations and carbon biomass (using equations of Menden Deuer and Lessard) for the same cell categories. Carbon fixation rates are then presented for: ratio of calcification/photosynthesis, photosynthesis, calcification, standard deviation of photosynthesis and calcification measurements, chlorophyll concentration within incubation bottles, chlorophyll normalized photosynthesis, and calcification. Finally, corrected salinity (based on bottle salinity), corrected SeaBird oxygen values based on lab oxygen titrations, dissolved inorganic carbon (DIC) concentrations, total alkalinity and concentration of CFC12 and CFC11 freons are presented.