Hot Stuff: How scientists are working to heat-proof coral reefs

November 4, 2023 6:16 PM

‘Heat-proofing’ coral: Aussie discovery throws a lifeline to world’s dying reefs. Australian biologists are using "assisted evolution" to breed heat tolerant algae in an attempt to make coral reefs more resistant to bleaching.
posted by neonamber (10 comments total)

Anything like this is a small bit of good news, but it still depresses me. There are much easier and globally-applicable ways to combat the effects of what we're doing to the planet, but we just won't, so people who care are reduced to applying a band-aid to a severed artery.
posted by Ickster at 12:31 AM on November 5, 2023 [3 favorites]

I’m sure this will end well, just like every other animal introduced to Australia for whatever purpose.
posted by LizBoBiz at 1:24 AM on November 5, 2023 [3 favorites]

I'm sure this will end well, helping ecosystems become more resilient to climate change.

We absolutely do need to work on keeping ecosystems viable despite climate change and it's good that people are doing so. No one who works in ecosystem management is in the least bit complacent about climate change from what I see.
posted by ambrosen at 2:36 AM on November 5, 2023 [5 favorites]

Fascinating. A very superficial skim of the author's paper didn't show anything about tolerating acidification, just heat. Does anyone know if this strategy would help with acidification as well?
posted by Wretch729 at 2:36 AM on November 5, 2023

I don't know how badly the microalgae in coral are affected by acidification, as they're symbionts with the actual coral polyps. The microalgae photosynthesise and provide energy to the coral polyps to keep them alive, but it's the coral polyps which create the calcium carbonate which is most harmed by ocean acidification.

As the microalgae are a different species from the coral polyps that they live in the tissues of, they can evolve separately so it does look as though acid tolerance and heat tolerance can be decoupled. Given that they photosynthesise, it's possible that higher CO₂ levels in the water may actually make that easier for them, notwithstanding the fact that higher CO₂ levels are overall a very bad thing.
posted by ambrosen at 3:04 AM on November 5, 2023

The concerns about heat and coral are with their symbiotic dinoflagellates, which swim away when they get too warm. The concerns about acidity and coral are about the coral's own ability to make calcium carbonate. Unfortunately, as far as I know, that concern is simply a chemical/physical reality that the reactions to form calcium carbonate will not happen at lower pH. Evolution can't fix physics.

(or on preview, what ambrosen said).
posted by hydropsyche at 3:07 AM on November 5, 2023 [2 favorites]

Ah, some corals are more robust to acidification than others. Yes there is a hard limit to pH and calcium carbonate deposition , but to my knowledge, the acidification we see at the moment is within evolution's grasp . (also if you want to follow this field, look at the google scholar page for the paper above) Whether these palau like corals would be viable for other reasons...or other stresses on reef systems caused by acidity are insolvable....I have no idea.

The problem as a layperson is not that evolution can't adapt, it can't adapt quickly enough.
posted by lalochezia at 5:23 AM on November 5, 2023 [4 favorites]

Sorry, I was unclear. Yes, some adaptation to a lower pH range is possible, which we know from corals that live at naturally occurring lower pH, and we are seeing evidence of adaptation to ocean acidification already. What I was trying to emphasize was that we are much closer to corals and other calcium carbonate dependent species hitting the lower physical limit for pH (for calcium carbonate formation to be physically possible) than we are from hitting the upper physical limit for temperature for life as we know it (100 C).
posted by hydropsyche at 10:15 AM on November 5, 2023 [1 favorite]

There are much easier and globally-applicable ways to combat the effects of what we're doing to the planet, but we just won't, so people who care are reduced to applying a band-aid to a severed artery.

I take issue with the fatalism implicit in "we just won't". It's not just fatalistic, it's wrong.

Renewable energy is progressing by leaps and bounds. It's about 80% cheaper than it was 15 years ago! The fossil fuel industry is still powerful and entrenched, but the cheaper renewable energy becomes, and the more sectors it can be applied to -- electricity, transportation, industry, etc. -- the less need there is for oil, gas, and coal.

Are we doing "enough" (whatever that might mean)? Probably not -- yet. But we're not doing nothing!
posted by Artifice_Eternity at 6:52 PM on November 5, 2023 [1 favorite]

Thank you all for the insight!
posted by Wretch729 at 5:51 PM on November 9, 2023