Assessing Ocean Alkalinity Enhancement impacts on biodiversity: general considerations to experimental research and first findings

Ocean Alkalinity Enhancement (OAE) is currently considered as one of the most promising methods for atmospheric carbon dioxide removal (CDR). This process involves adding alkaline substances to seawater to accelerate the ocean’s natural carbon sink.

There are various methods to increase the ocean’s alkalinity locally, but there are concerns regarding the risk for the marine environment and its biodiversity. Indeed, the impact of changes in alkalinity on marine species and ecosystems is poorly understood. Given that some researchers and industrial companies also believe and sell the idea of OAE as a technically and economically feasible global application, it is crucial to assess its potential impacts. This includes evaluating the effects of changing alkalinity alone and in combination with other key trace elements that may be released during implementation, to ensure that any field manipulation does not cause harmful biological effects to the marine environment.

Laboratory experiments, alongside other techniques, play a significant role in addressing these risk assessments. This presentation aims to provide insights into experimental designs, compare the strengths and weaknesses of different approaches, and highlight results from a series of experiments conducted on marine organisms including corals, echinoderms and bivalves.