Samples were collected offshore from Alligator Reef (2014) and Looe Key Reef (2015-2016). Measurements included temperature, salinity, pH, abundance of Vibrio, chlorophyll-a, DOC, TDN, DON, NH4, NO3, NO2, Orthophosphate ,SiO4, and dFe.
Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were determined using the filtrate of water samples that were passed through precombusted 25 mm GF/F filters and stored frozen (-20C) until analysis. Samples were subsequently analyzed using the High Temperature Catalytic Oxidation method on a Shimadzu TOC-Vs analyzer with nitrogen module. Standard curves were run twice daily using a DIW blank and five concentrations of either acid potassium phthalate solution or potassium nitrate for DOC and TDN, respectively. Three to five subsamples were taken from each standard and water sample and injected in sequence. Reagent grade glucosamine was used as a laboratory check standard and inserted throughout each run, as were Certified Reference Material Program (CRMP) deep-water standards of known DOC/TDN concentration.
Nutrients data went through internal lab QAQC process. BDL means below detection limit. The method detection limit (MDL) was determined using 9 samples on two different runs and correct student-T value.