Phytoplankton diversity along with carbon and nitrogen uptake rates collected along the GO-SHIP IO9 repeat hydrography section of the Indian Ocean from R/V Roger Revelle cruise RR1604 from March to April 2016 (NCEI Accession 0278135)

Acquisition Description:
All nutrient and cell count methodology is described in the published work coming out of this data set (see below).

Samples were initially collected with a CTD/Niskin rosette, as supplied by the ship.

Urea and total dissolved phosphorus (for calculation of dissolved organic phosphorus) were determined on a Thermo Scientific Genesys 10UV spectrophotometer. See Lomas et al. (2010) for a description of the latter.

Cell counts for heterotrophic bacteria and nanoplankton (<20 um) cells were performed on a BD FACSJazz flow cytometer, using standard methods and 0.53 um bead stocks for reference material. Visualization of heterotrophic bacteria was performed with SYBR Green stain.

Biomass calculations were derived from flow cytometry data output, as per Casey et al. (2013).

Larger (>20 um) autotrophs were enumerated on a FlowCam (Fluid Imagining Technologies).

Biomass and isotopic enrichment, used to calculate specific and absolute uptake rates, were assessed on a Thermo Finnegan Delta V mass spectrometer, as operated by the Bigelow Analytical Services team.

Sample accuracy was assessed by using certified standards, for those measurements where standards are available. Certified standards were run with each analytical run and compared to long term control charts for respective analyses. For those analyses where there are no standards (e.g., flow cytometric cell counts) data were assessed for reasonableness based upon extensive experience of the PI’s.