Measuring Coastal Acidification Using In-Situ Sensors in the National Estuary Program
On this page:
Beginning in 2015, the US EPA's National Estuary Program began a collaboration with partners in seven estuaries on the East Coast, West Coast, and Gulf of Mexico to expand the use of autonomous monitoring sensors for coastal acidification data collection. This effort demonstrated that high-quality carboante chemistry observations can be recorded from estuarine environments using autonomous sensors originally designed for open-ocean settings. In Tillamook estuary, ORD scientists assessed the performance of three commonly-used biogeochemical sensors was compared over a period of 5 years- the YSI EXO series water quality sonde, SeaBird SeapHOx, and SAMI-CO2. The goals of the analysis were to quantify field measurement uncertainties for each instrument, assess the suitability of the observational data for calculating derived carbonate system variables (e.g. CaCO3 saturation states), and characterize the ability of the monitoring program to evaluate common OA endpoints (e.g. organismal stress threshold exceedances) based on propagated uncertainties. The sensors evaluated in this study are commonly used by other estuarine monitoring programs, and the broad ranges of salinity (0 - 33.5), temperature (7.4 - 20.2°C), and carbonate system parameters (pHT: 6.9 - 8.4; ¿aragonite: 0 – 5.1 ) over which we evaluated the uncertainties of the monitoring system make our results relevant for further development of best-practices for the broader estuarine OA monitoring community.