It is known by experts as an invisible threat - but one which is unravelling marine life, food chains and entire economies. That is the conclusion of new research on the critical threat of ocean acidification. Scientists discussed the problem at the COP16 biodiversity conference in Colombia last month; and it is among issues at the COP29 climate change conference, which is underway in Azerbaijan. In Perspective, we spoke to post doctoral researcher at the Potsdam Institute for Climate Impact Research, Dr Sabine Mathesius.