Dataset: Dissolved Organic Carbon concentrations collected at the Mo’orea LTER forereef and back reef sites during the 2019 coral bleaching event.

Samples were collected either via Niskin bottle or by hand on SCUBA at Mo’orea, French Polynesia during the 2019 coral bleaching event (April, May).  Time is approximate (within + or - 2 hours) because the time reported is the dive time, not the exact time of sample collection.  

In all cases new Whirl Pak bags were used to collect the water samples, which were immediately put on ice and transported back to the lab. The water samples were filtered through precombusted Whatman GF/Fs and the water that passed through was collected in an acid washed container, and then frozen.  All filtration equipment was acid washed and Milli-Q washed, and then flushed with sample water prior to sample filtration and water collection.

Samples were kept frozen at -20 degrees C until analysis.  All analyses were completed within 6 months of collection by Nutrient Analytical Services at the Chesapeake Biological Laboratory of the University of Maryland Center for Environmental Science.

Samples were acidified and sparged with ultra-pure carrier-grade air to drive off inorganic carbon and analyzed with a high-temperature combustion (680 C) method on the Shimadzu TOC-L.  Operating procedures followed those outlined for 'Total and Dissolved Organic Carbon Method' (https://www.umces.edu/nasl/methods). In short, all carbon compounds are broken down into CO2 which is carried by ultra-pure air to a non-dispersive infrared detector (NDIR) for detection. The system was calibrated before and after each run with potassium hydrogen phthalate standards (6-point curve, 0-20 mg C/L) and referenced against a certified reference control sample (Scp Science Accuspec Toc Standard), a spike (20 ppm) and a blank every 10 samples. The acceptance criteria used was 0.995.