Warming Oceans Are Changing Australian Reefs

Rising ocean temperatures are affecting shallow reefs and the organisms that thrive there. However, these effects are unknown due to the scarcity of accurate local data.

Image Credit: Shutterstock.com/katatonia82

For over ten years, a group of scientists in Australia has been monitoring the country’s reefs and their changes. The researchers employed fine-scale data to show the impacts of warming waters on tropical and temperate reef fish communities.

The study was published in the journal Current Biology on September 22nd2022.

Reefs provide a ton of benefits to people, from food, livelihoods, recreation, physical protection from storms, and I dare say even happiness and inspiration. We specifically considered the fishes that live on reefs, as these are important for many of those aspects, and also help maintain the natural ecological function of the reefs.

Rick Stuart-Smith, Study Lead Author and Marine Ecologist, University of Tasmania

Global data is collected through the Reef Life Survey, which Stuart-Smith and Co-Author Graham Edgar developed to provide global information on the state of Australia’s reefs. Data from two other significant reef monitoring programs were integrated with information from the Australian Reef Life Survey for this research.

The two other datasets we used are amongst the longest running of any reef biodiversity monitoring programs globally. The combination of these datasets provided a more comprehensive picture of what is happening on reefs than would be imaginable for any other continent.

Rick Stuart-Smith, Study Lead Author and Marine Ecologist, University of Tasmania

The research groups examined temperature and habitat change, such as coral bleaching, and discovered that the effects differed depending on where the reef was.

Tropical reef fish were more impacted by habitat change, while fish on temperate and subtropical reefs reacted more to temperature change.

Temperate reefs experienced an invasion of tropical fish when a marine heatwave in 2011 warmed seas in southern Australia. These species persisted for years after the incident.

The researchers also evaluated how the loss of kelp and coral cover resulted in fewer unique fish populations. North-eastern Australian regions revealed evidence of habitat degradation that resulted in fish populations being dominated by generalist species in place of niche species adapted to particular habitats.

Stuart-Smith is optimistic that the current study will promote more extensive, standardized, and coordinated local research, which can be utilized to assess global trends more effectively. The group also advocates for future research on reefs and the climate.

The authors concluded, “Climate change clearly has a huge impact on marine biodiversity, with changes we observed around the Australian continent over short time scales indicating that much larger changes are likely over the next half century as ocean warming progresses. “

Journal Reference

Stuart-Smith, RD, et al. (2022) Tracking widespread climate-driven change on temperate and tropical reefs. Current Biology. doi.org/10.1016/j.cub.2022.07.067.

Source: https://www.cell.com/