How seagrass survives in low light could help future crops

In the Mediterranean Sea, vast underwater meadows of seagrass grow in places where sunlight is weak. Yet these plants continue to photosynthesise efficiently, produce oxygen, store carbon and suppor marine life.A new study has revealed how one of these seagrasses has changed its photosynthetic proxcess to make the most of the limited light available underwater.The study, published in Nature Communications, focused on Posidonia oceanica, a seagrass found only in the Mediterranean Sea. It grows from shallow coastal waters to depths of around 50 metres, where sunlight is much weaker and red light has almost disappeared because water absorbs it quickly.Unlike seaweeds, seagrasses are flowering plants. Their ancestors once lived on land before returning to the sea between 70 and 100 million years ago.Today, Posidonia oceanica forms large underwater meadows that are among the world's most productive ecosystems.