Coral bleaching study examines algae’s protective effect during marine heatwaves

[Australia] Scientists are placing terracotta tiles in sections of reef along the West Australian coastline to assess the resilience of coral species and also the extent algae can help protect species from coral bleaching caused by marine heatwaves.

The research, coordinated by the CSIRO and the Department of Parks and Wildlife (DPAW), seeks to measure the rate of coral “recruitment”, where coral larvae attach and establish themselves on a reef.

It spans a wide range of marine ecosystems from Shark Bay to Dampier, including the Ningaloo reef and Monte Bello Islands.

CSIRO experimental scientist Damian Thompson said they were trying to discover the interaction between species in different systems.

“Effectively we’ve got these quite distinct regions, and we really don’t know how well those areas are connected … can coral from one area provide larvae that settles in one of the other areas?”

“One of the big challenges is understanding the connectivity of the [Pilbara] region, what we’ve done is come up with a connectivity model that allows us to predict the number of coral settling in any given area”.

Algae provides bleaching protection hope

He said researchers had already made some interesting discoveries.

“We are learning that different corals have different levels of resistance to heating events, largely due to the type of algae that they harbour in their tissues,” he said.

“We know that some corals have very high numbers of heat resistant strains of [algae] … so we are still learning a lot about how adult colonies and also juveniles can effectively shuffle these [algae] in and out of their tissue to adapt to different conditions.”


The terracotta plates measure 10cm by 10cm in size and are being attached to different areas of reef prior to a coral spawning event in March.

Mr Thompson said deciding where to place the tiles was important for a number of reasons.

“When you’re comparing different locations you try to standardise as much as possible, so we’ll pick similar depths and similar exposure to things like waves and sediment input”.

“One of the things we are also looking at in this study is gradients, so around Dampier we’ve got five locations in shore, five locations in the mid-shelf area, and then we’ve got five offshore locations which are the most exposed.

“We leave them [tiles] there for approximately three to four months and the baby corals settle onto these terracotta plates, then we remove them from the reef … and count the number of coral babies on the tiles,” he said.


View original article at: Coral bleaching study examines algae’s protective effect during marine heatwaves

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