On the western side of Lake Macquarie in New South Wales, Australia, sits Myuna Bay, a quiet bay with meadows of seagrass waving beneath the water. The most common marine plant species you find there is Zostera muelleri. It has long ribbon-like leaves that grow from stems (called rhizomes) buried beneath the sediment and provides important shelter for small fish, shrimp and crabs.

Although Myuna Bay looks quite normal, it is actually a bit unusual. For decades, the nearby Eraring power station released warm water into the lake that was used to cool down their systems, causing water temperatures here to be consistently 1°C to 3°C higher than nearby sites.

This made the bay a rare natural laboratory for understanding what warming oceans might mean for coastal ecosystems.

In our new research, published today in the journal New Phytologist, we used this setting to investigate what happens to seagrass and the microbes living in the sediment when ocean temperatures increase in the way climate models predict they will in the future.

One of the most important coastal habitats

Seagrasses are often overlooked, but they are among the most important coastal habitats on Earth.

They are marine flowering plants that stabilise sediments, improve water clarity and provide food and shelter for many marine animals. They........

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