Abstract
Observations of seawater carbonate ion concentrations are critical to assess the ecological effects of ocean acidification . Nevertheless, currently available methods are labor intensive or too complex for field applications. Here, we report the design and performance of the first fully automated portable carbonate ion analyzer. Measurements are based on reaction of carbonate and chloride ions with Pb(II) followed by quantitative UV spectrophotometric detection of the PbCO 3 0 complex. The core hardware is a syringe pump equipped with a multi-position valve that is controlled by software written in LabVIEW. Measurement precision is 1.1% ( n = 13) with a measurement frequency of 12 h −1 . The analyzer was used to continuously monitor carbonate ion concentration variations in a 2500 L coral reef tank for five days (test 1), and used for shipboard underway and vertical profile analysis during a 13-day cruise (test 2). The analyzer attained a combined standard uncertainty of 3.0%, which meets the Global Ocean Acidification Observing Network's “weather level” goal. Through use of a syringe pump mechanism for mixing seawater and reagent solution, the analyzer is robust, functionally flexible, and quite suitable for continuous environmental monitoring under harsh conditions.
Original language | American English |
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Journal | Marine Chemistry |
Volume | 209 |
DOIs | |
State | Published - Jan 1 2019 |
Keywords
- Seawater
- Carbonate ion
- Automated flow analysis
- Spectrophotometric detection
- Coral reef
- Underway analysis
Disciplines
- Life Sciences