Dataset: Water quality metrics collected from reef water in the Flower Garden Banks National Marine Sanctuary in Mar 2023

Collection

At each sampling location, we collected reef seawater for water quality metrics: the microbial community of the surrounding environment, the total organic carbon and total nitrogen, and cell abundances. Water was collected via SCUBA 2 m above the reef. Samples were collected in acid-washed and seawater-rinsed bottles.

To quantify cell abundances of Prochlorococcus, Synechococcus, picoeukaryotes, and unpigmented (presumably heterotrophic bacteria/archaea) microorganisms, seawater (1.4 mL) was preserved using paraformaldehyde, and frozen in liquid nitrogen vapors. Water for non-purgeable organic carbon (TOC) and organic nitrogen was collected into combusted, borosilicate EPA vials and acidified with phosphoric acid, then stored at 4 degrees Celsius.

Sample processing will be conducted using previously published methods (Becker et al., 2020; Weber et al., 2020). 

Cell abundances

Acid-washed and seawater-rinsed bottles (HDPE, Nalgene, Thermo - Fisher Scientific);  2 ml cryovial (Corning); 1% paraformaldehyde (Electron Microscopy Sciences); Beckman-Coulter Altra flow cytometer (Beckman Coulter Life Sciences) that was attached to a Harvard Apparatus syringe pump and  stained with Hoechst 33342 DNA stain (1 μg ml−1 final concentration) and excited co-linearly by 488 nm (1W) and UV (~350 nm, 200 mW) lasers (Becker et al., 2020). 

Total organic carbon and total nitrogen

After preservation with phosphoric acid, TOC and TN concentrations will be determined using a Shimadzu TOC-VCSH total organic carbon analyzer equipped with a TNM-1 module at Woods Hole Oceanographic Institution. Results will be made available after they have been processed.