Ocean Acidification

• The paper addresses the potential impacts of CO₂ enrichment in the marine environment.

• Two different marine microalgae species were used through four consecutive generations.

• T. chuii showed a slight adaptation through generations, in terms of metabolic activity.

• P. tricornutum was the most sensitive one with almost total growth inhibition in the fourth generation.

• The results give valuable data about the transgenerational effects of CO₂ enrichment on microalgae.

Abstract

As a result of the increasing pressure provoked by anthropogenic activities, the world climate is changing and oceans health is in danger. One of the most important factors affecting the marine environment is the well-known process called ocean acidification. Also, there are other natural or anthropogenic processes that produce an enrichment of CO2 in the marine environment (CO2 leakages from Carbon Capture and Storage technologies (CCS), organic matter diagenesis, volcanic vents, etc). Most of the studies related to acidification of the marine environment by enrichment of CO2 have been focused on short-term experiments. To evaluate the effects related to CO2 enrichment, laboratory-scale experiments were performed using the marine microalgae Tetraselmis chuii and Phaeodactylum tricornutum. Three different pH values (two treatments – pH 7.4 and 6.0 – and a control – pH 8.0) were tested on the selected species across four consecutive generations. Seawater was collected and exposed to different scenarios of CO2 enrichment by means of CO2 injection. The results showed different effects depending on the species and the generation used. Effects on T. chuii were shown on cell density, chlorophyll-a and metabolic activity, however, a slight adaptation across generations was found in this last parameter. P. tricornutum was more sensitive to acidification conditions through generations, with practically total growth inhibition in the fourth one. The conclusions obtained in this work are useful to address the potential ecological risk related to acidification by enrichment of CO2 on the marine ecosystem by using consecutive generations of microalgae.

Bautista-Chamizo E., Borrero-Santiago A. R., De Orte M. R., DelValls A. & Riba I., 2018. Effects of CO2 enrichment on two microalgae species: a toxicity approach using consecutive generations. Chemosphere 213: 84-91. Article (subscription required).