Two-thirds of the Earth’s surface is covered by marine waters. This vast marine ecosystem is vulnerable to anthropogenic stressors such as pollution, overfishing, plastics and ocean acidification. Such unsustainable use of our seas is threatening the fragile balance of marine ecosystems. For instance, across all of Europe's regional seas, only 7 % of marine species assessments indicate 'favourable conservation status'. Effects of climate change add to the cumulative impacts. The EU-funded ATLANTIS project will develop a model for quantifying impacts on ecosystem service losses, as well as impacts of marine plastic debris and of marine invasive species within the life cycle assessment framework. The findings will help ensure sustainable marine ecosystem management.