Rare undersea volcanic vents show oceans’ increasing acidity likely to hurt biodiversity, endanger ecosystem stability, say Stanford researchers

BY Louis Bergeron, Posted on Stanford Report, September 12, 2011 — Some rare undersea volcanic vents that emit carbon dioxide – which makes the water around them more acidic – have given Stanford researchers a look at how marine ecosystems may be affected as global warming intensifies. Carbon dioxide is the principal greenhouse gas causing global warming, and as it accumulates in the atmosphere, it also moves into the ocean and increases its acidity.

Stanford researchers have gotten a glimpse into an uncertain future where increasing levels of carbon dioxide in the Earth’s atmosphere will lead to higher levels in the ocean as well, leaving the water more acidic and altering underwater ecosystems.


The glimpse comes from waters near Ischia, Italy, where unusual shallow-water volcanic vents in the floor of the Mediterranean Sea bubble carbon dioxide into the water, creating a local underwater neighborhood that may resemble the ocean of the future.


If the results are a prediction of  the future, “you are left with a dramatically different ecosystem that is likely going to be less able to deal with stress and is going to have less biomass available to feed organisms higher up the food chain,” said Kristy Kroeker, a graduate student in biology at Stanford’s Hopkins Marine Station.

The special significance of this research site is that, unlike most hydrothermal vents, it spouts just carbon dioxide, without hot, sulfurous brews that are lethal to all but the most highly adapted extremophile organisms. The carbon dioxide comes out of the vents at the same temperature as the surrounding water.

The carbon dioxide vents cause a local gradient in the seawater chemistry, with the greatest acidity closest to the vents. While the researchers found that various species reacted differently to the more acidified waters – some suffered, some prospered – their overall findings do not bode well for the biological community as a whole.

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