Water chemistry at coral reef sites in Timor-Leste from discrete surface and bottom water samples collected from 2013-06-06 to 2014-10-06 (NCEI Accession 0168915)

The water chemistry data described here are from discrete water samples collected by the NOAA Coral Reef Ecosystem Program (CREP) in 2013 and 2014 to assess the seawater carbonate systems primarily at fixed climate survey sites located in coral reef habitats in Timor-Leste. Climate sites were established by CREP to establish ecological baselines for climate change by measuring multiple features of the coral reef environment (in addition to the data described herein) over time. Water chemistry data for both 2013 and 2014 is only available for a subset of the established climate survey sites (5 of the 8 sites). In 2013, water samples were collected at a few random sites in addition to the samples collected at the climate survey sites.

SCUBA divers collected two discrete water samples from each site; one at the reef and one at the surface directly above the reef. In 2013 only, surface water samples were also collected ~1 km offshore from the survey site. The water samples were processed by CREP and sent to NOAA Pacific Marine Environmental Laboratory (PMEL) In Seattle, WA to be analyzed for total alkalinity (TA) and dissolved inorganic carbon (DIC). From these constituents, alongside temperature, salinity, and depth data, other parameters of the seawater carbonate system were calculated, including pH, partial pressure of carbon dioxide, and aragonite saturation state.

Laboratory experiments reveal calcification rates of crustose coralline algae (CCA) are strongly correlated to seawater aragonite saturation state. Predictions of reduced coral calcification rates, due to ocean acidification, suggest that coral reef communities will undergo ecological phase shifts as calcifying organisms are negatively impacted by changing seawater chemistry. These water chemistry data for Timor-Leste, along with other data collected at the climate survey sites (water temperature, calcification rates, invertebrate biodiversity, and benthic cover, all archived separately), can be used to help scientists assess and understand how Timor-Leste's coral reefs are responding to ocean acidification.

NOTE: This data has been found to have errors in the salinity used to calculate Total Alkalinity, Dissolved Organic Carbon, pCO2, pH, and Aragonite Saturation State, and as such should not be used for scientific purposes. All parameters of this data are being actively curated and an updated, fully rectified version is expected to be submitted prior to the end of calendar year 2021.