Evaluation of a semi-automatic system for long-term seawater carbonate chemistry manipulation

• Published in: Revista chilena de historia natural
• Main Authors: TORRES, RODRIGO, MANRIQUEZ, PATRICIO H., DUARTE, CRISTIAN, NAVARRO, JORGE M., LAGOS, NELSON A., VARGAS, CRISTIAN A., LARDIES, MARCO A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Sociedad de Biología de Chile 2013
• Subjects: Carbonate chemistry manipulation; Ocean acidification
• Online Access: http://repositorio.unab.cl/xmlui/handle/ria/971; https://doi.org/10.4067/S0716-078X2013000400006

Indexación: Web of Science; Scielo. The assessment of the effects of Ocean Acidification (OA) on marine life has received increasing attention in recent marine research. On a mesocosmic scale, the CO2 levels in seawater can be manipulated to evaluate experimentally the consequences of OA on marine organisms (vertebrates and invertebrates). An ideal manipulation of carbonate chemistry should mimic exactly the changes to carbonate chemistry, which will occur in years to come. Although some methods have been described in the literature, here we describe in detail a simple, robust and inexpensive system to produce CO2-enriched seawater by bubbling the seawater with air-CO2 mixtures. The system uses mass flow controllers (MFC) to blend atmospheric air with pure CO2 to produce two pCO2 levels. The air-CO2 mixtures are delivered continuously to seawater equilibration reservoirs, and simultaneously to an infrared CO2 analyser to verify CO2 levels in the air-CO2 mixture delivered to the equilibration tanks. We monitored both pH and total alkalinity in the equilibration reservoirs over a period of one year in order to document the long-term performance of this system for simulating the future carbonate chemistry of seawater in a coastal laboratory. System performance was sufficient to maintain three contrasting (e.g., 397, 709 and 1032 matm) and relatively constant (the coefficient of variability was 11 %, 9 % and 9 % respectively) seawater pCO2 during a year-long monitoring. La evaluación de los efectos de la acidificación oceánica en la vida marina ha recibido creciente atención en la actual investigación marina. A escala de "mesocosmos" los niveles de CO2 del agua de mar pueden ser manipulados para permitir la experimentación con organismos marinos (vertebrados e invertebrados). Una manipulación óptima de la química del carbono debiese emular exactamente los cambios esperado en la química del carbono. A pesar que algunos métodos han sido descritos en la literatura, el presente estudio describe en detalle un sistema ...