Deep ocean reefs are likely to transform with global warming bringing together species from temperate and tropical waters that may have never coexisted before. This was the finding of new research published in Nature Climate Change that modelled how habitat-forming species on deep reefs along Eastern Australia respond to rising water temperatures driven by climate change.

The modelling predicted many species of deep-sea sponges and corals will contract their distribution to cooler southerly waters as their habitats experience ‘tropicalisation’ in coming decades, and that different groups of organisms will respond to warming in different ways.

This process will lead to sub-tropical species sharing deep reefs with organisms that already live in more temperate waters, creating novel mixed communities.

While shallow reefs have been extensively studied, this was he first time a study looked at how deep reefs would be affected. These deep reefs are diverse and productive, making them vital for healthy ecosystems.

To get their results the researchers analysed 13 groups of deep reef invertebrate species across the full latitude of temperate eastern Australian waters. They found that distribution of the invertebrates was primarily related to ocean temperatures.

The study showed warming ocean temperatures changed distributions with coral and sponges in sub tropical waters shifting southwards. However, species in temperate waters were restricted by the southerly extent of the continental shelf. The modelling showed new assemblages of species were forced together creating ecosystems that had no counterpart today.

These changes are likely to have significant consequences for the way deep reef systems operate and how productive they become.