New study highlights the impact of two new marine gases on climate models’ accuracy
January 31, 2023
A new study published in Science Advances led by the Institut de Ciències del Mar (ICM) has revealed that plankton in polar oceans emits benzene and toluene, two gases of biological origin that contribute to cloud formation and affect climate. In addition to oxygen, nitrogen or carbon dioxide, the air we breathe contains small amounts of organic gases, such as benzene and toluene. These oxidize into small particles or aerosols that contribute to the condensation of water in the droplets that form clouds. The new study describes the first measurements of benzene and toluene in polar oceans and indicates that these compounds have a biological origin. Until now, their presence in polar marine air was thought to be a proof of the extent of human pollution from coal and oil combustion or solvent use, among others. To carry out the study, the team measured the concentrations of benzene and toluene in surface water and air during the course of two oceanographic campaigns: one in the Arctic and the other in the Southern Ocean. The distribution of these gases, their relationship to the amount of phytoplankton, and the fact that the ocean was constantly emitting them into the atmosphere rather than capturing them from it, led the researchers to conclude that they were of biological origin. Then, by incorporating the data into a global atmospheric chemistry and climate model, the scientific team realized that benzene and toluene emitted by the ocean contributed significantly to aerosol production. This was especially true in the extremely clean and unpolluted atmosphere of the Southern Ocean, where these two gases increased the amount of organic aerosols by 8% and up to 80% in transient situations. According to the authors of the paper, the natural effect of marine benzene and toluene on atmospheric chemistry was most likely a widespread and global phenomenon before the Industrial Revolution. However, it would now be masked by the widespread impact of pollution.