From the timing, it looks as if an episode of marked oceanic oxygen deficiency during the Cretaceous was the result of undersea volcanism. Studies of such events are relevant to the warming world of today.

Much of the scientific and public focus on anthropogenic carbon dioxide emissions have been on climate impacts. Emission targets have been suggested based primarily on arguments for preventing climate from shifting significantly from its preindustrial state. However, recent studies underline a second major impact of carbon emissions: ocean acidification. Over the past 200 years, the oceans have take up `40% of the anthropogenic CO2 emissions. This uptake shows the rise in atmospheric CO2 considerably, thus alleviating climate change caused by anthropogenic greenhouse gas emissions.

Here the authors show the effects of acidification on benthic ecosystems at shallow coastal sites where volcanic CO2 vents lower the pH of the water column. Along gradients of normal pH (8.1

Rising levels of atmospheric carbon dioxide lead to acidification of the oceans. A site in the Mediterranean, naturally carbonated by under-sea volcanoes, provides clues to the possible effects on marine ecosystems.

Increasing tropospheric ozone levels over the past 150 years have led to a significant climate perturbation; the prediction of future trends in tropospheric ozone will require a full understanding of both its precursor emissions and its destruction processes. A large proportion of tropospheric ozone loss occurs in the tropical marine boundary layer and is thought to be driven primarily by high ozone photolysis rates in the presence of high concentrations of water vapour.

Halogens are known to decrease the levels of stratospheric ozone. The latest measurements show that something similar occurs in the lower atmosphere over tropical oceans