Lecture: Wednesday 18th September 2019: “Ocean Acidification: A Tale of Rocks and Water” – Dr. Rachel R. Cave (NUIG)

Ocean Acidification: A Tale of Rocks and Water

By Rachel R. Cave (NUIG)
Climate change is now widely understood as an emerging challenge for human society. The adding of CO 2 to the atmosphere by a range of human activities is the main culprit, and this CO 2 traps heat, leading to global warming. This, in turn, strengthens the water cycle where more water is evaporated from the oceans into clouds and so falls as precipitation on land, to be returned to the oceans by rivers and submarine groundwater discharge. The “other” CO 2 problem is the effect that CO 2 has when it diffuses into seawater: it reacts with the water molecules to produce free hydrogen ions, which lowers the pH and so causes “ocean acidification”. This process has enormous implications both for shelled organisms and for the
ocean chemistry that supports plant life in the oceans. Ocean acidification in the open ocean is reasonably well understood, but things get much more complicated in coastal waters, which act as both a source and a sink of CO 2 , switching between them at different seasons. The carbon chemistry of coastal waters has three main controls: the cycle of growth and decay of phytoplankton and seaweeds, the exchange of waters with the wider ocean, and CO 2 exchange with the atmosphere. However recent work in Irish coastal waters shows that the rock underlying river catchments is also important in
the carbon chemistry of coastal waters.

This talk will give an overview of ocean acidification in the wider ocean and then look at what is happening in Irish waters, and why our geology is so important when it comes to coastal waters.

When and where: The lecture theatre in the Geological Survey of Ireland, Beggars Bush, Dublin 4 on
Wednesday, 18 September 2019, between 6:30 pm and 7:30 pm. Coffee and biscuits will be available from
5:30 pm. All are welcome!