Dataset: Benthic metabolism vs coral cover - Bermuda

General study design:
Coral communities with different benthic cover (0, 40, 80%) were created in flow-through mesocosms exposed to natural environmental variations. The experiment was designed to examine how benthic metabolism influence diurnal seawater carbonate chemistry and how this scales with varying coral cover. The experiment was conducted at the Bermuda Institute of Ocean Sciences (BIOS).

Methods description:
Coral communities with planar surface area ranging from 0, 40 and 80 percent were created within flow-through mesocosms. Diurnal seawater chemistry was measured for communities during August 2012 by taking hourly water measurements (T, S, DO_sat, DO_conc, and pH) and collecting water samples for dissolved inorganic carbon (DIC) and total alkalinity (TA) every 3 hours over 24-hour time periods. Seawater chemistry data were used to calculate diurnal net community production (NCP) and net community calcification (NCC) rates using modified standard equations (Langdon et al. 2010).

Analytical Methods:
Seawater samples were collected by hand using 250 ml Pyrex glass bottles and fixed with 100 µL HgCl2 as per standard protocols (Dickson et al. 2007). Handheld YSI multi-meter instrument was used to measure temperature, salinity, dissolved oxygen, and pH at the time of sampling. All seawater samples were transported to the Scripps Coastal and Open Ocean Biogeochemistry lab and analyzed for TA via an open-cell potentiometric acid titration system developed at Scripps Institution of Oceanography (SIO) by A. Dickson (Dickson et al. 2007) and DIC via an automated infra-red inorganic carbon analyzer (AIRICA, Marianda Inc).

Quality Control:
Standard protocols were followed for sampling and analysis of seawater TA and DIC (Dickson et al. 2007). YSI multi-meter instrument was calibrated prior to each sampling period with accuracies of 0.15 °C for temperature, 1% for salinity, ±2% for dissolved oxygen saturation, 0.2 mg/L for dissolved oxygen concentration, and 0.2 for pH. The accuracy and precision of TA (-0.85 ± 1.51 μmol/kg) and DIC (1.45 ± 2.62 μmol/kg) measurements were evaluated using certified reference materials (CRM) provided by the laboratory of A. Dickson at SIO and analyzed every 5 samples for DIC and ~15-20 samples for TA.

For additional information please see Page et al. (2017).

Known Problems:
A few samples were lost during transit due to broken bottles. Additionally, a few DIC and TA data points did not pass QAQC and therefore were omitted.