84% of the coral reefs hit by worst bleaching event on record | Hacker News Reader

84% of the coral reefs hit by worst bleaching event on record

apnews.com

31 pointsgmays8 comments

Hank Green recently did a good video on coral reefs with the thesis that coral reefs are not doomed by anthropogenic climate change. Rather, climate change is one component of what is essentially a multi-front war that humanity is unwittingly staging on our coral reefs that also includes overfishing, habitat destruction/disturbance, and pollution.

He brings on an advocate for reef restoration from the Coral Reef Alliance who mentions that some reefs have adapted to changing ocean conditions and provides examples of programs that help shelter reefs so that those better adapted coral species can spread.

Link: https://www.youtube.com/watch?v=hxZDyV-E5WY

Assuming that this story is true, is it posible that evolutionary pressure sees most coral species replaced by species that can withstand higher temperatures?

I like to think that if there were already plenty of such high-temp coral available to select from, the alarm bells wouldn't be ringing so hard.

We're giving fauna and flora very little time to adapt

They grow very slowly so it takes many decades to replace a reef not unlike replacing a forest

.. not unlike replacing a forest

Great example: you can't (replace a forest). Whatever grows back, will be different from a previous untouched-by-humans state.

Same goes for a coral reef. And species depending on it, may disappear (perhaps permanently!) along with the coral itself.

Possible but unlikely, coral is two species in symbiosis so slow to evolve, and the planet is warming very, very fast compared to any historic rates.

I probably didn't give enpugh context here, but the maincoral gets nutrition from the colourful algae on its surface. When temperatures rise, the algae gives off toxins, so the main coral rejects the algae (and then later dies because it has no food source).

It's really hard for that kind of process to evolve out, but some scientists are having success hardening coral in labs (so it'll reject algae less hastily) before releasing them into the wild

Yes, if there is enough time for them to adapt to rising heat, ocean acidification due to dissolved CO2, and changing ecologies.

https://www.eea.europa.eu/en/analysis/maps-and-charts/ocean-...

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