Bleached corals thrive within days when touching healthy neighbour
nature.comComments
Bleaching is actually due to the coral expelling those algae. Bleached corals are not dead, and remarkably they can not only let the algae in again but can also select a different algae species to cultivate (changing colour in the process)!.
This is thought to be a deliberate survival strategy to optimize the species of algae under different conditions (Adaptive Bleaching Hypothesis).
Bleaching is caused by the same stressors (like high temperature) which kill coral, but bleaching itself is not death of the coral.
My open questions would be:
1. What's the consequence of corals expelling algae?
2. Why does heat make corals expel algae?
Impressive that corals have such a survival mechanism. But hopeless if no other species of algae can enter another symbiotic relationship with them?
TLDR Yes but it's complicated. There are more suitable algae species but AFAIK coral under heat stress will still often expel the algae even if the algae isn't the one stressing the coral. So you have to essentially breed a more tolerant coral and then provide the algae.
Now luckily there do exist more heat tolerant coral and algae species living alongside each other. Unfortunately those species are located in the Persian Gulf/inside the Strait of Hormuz so they are regularly subject to added stressors from Oil/NG extraction, military conflicts, and waste dumping. And of course their location makes research on them/collaboration between research institutions complicated.
And it's not like you can just transplant these coral somewhere else and they'll live. They are adapted to their environment and that environment plays a part in their heat tolerance as well. But research on these coral ecosystems will likely shed a light on how to help other coral species to adapt and evolve.
Maybe the pharmaceutical industry can target a new market here...
So more CO2 in air = more CO2 in the water = lower PH in the ocean. I don't know the details but the more acidic water messes with the chemical processes that corals and other aquatic life depend on.
In the long run, there are huge deposits of calcium carbonate on the ocean floor. Even if we burn all of the fossil fuels, the ocean eventually comes back to a neutral ph.
The problem is the short run. We're turning CO2 into carbonic acid at a rate that far exceeds what surface waters can handle. This is creating conditions where shellfish of all kinds are working overtime form proper shells. If they can at all. It even affects many kinds of plankton. This stress is causing large dieoffs. When we wipe out things at the base of the food chain, it has ripple effects through the rest of the ecosystem.
Due to the coral or due to the algae? Put another way, could we engineer UV resistance into the algae?
And so does the coral!
If a species of algae cannot handle high temperatures without generating chemicals like hydrogen peroxide which trigger the bleaching, then that species is ejected sooner and more frequently during warmer months, creating selective pressure for species that can.
To survive these conditions without getting ejected, the algae need to essentially run their photosynthesis process more slowly. They produce less chlorophyll per cell and create sacrificial 'photoprotective carotenoid pigments' which act like sunscreen and dissipate that potential sunlight energy as useless heat (coral has a few tricks too fluorescent proteins).
So the coral is actually in a delicate balancing act, selecting the most aggressive/productive algae which won't also try to kill it during summer. Corals will learn to be more conservative in their selection and algae will get more conservative themselves. We want this process to happen quickly enough so that we don't lose coral coverage and diversity in the coming decades / centuries, but we can be confident that on longer timescales the coral will adapt, assuming we don't get runaway warming.
https://www.npr.org/2024/04/17/1245085914/coral-reefs-bleach...
I'm so glad we have space rockets, flying cars and drone warfare...but I'd trade it all in for the reef to come back.
It's really just climate change. (Ocean warming is what causes bleaching.) Luckily, since the 80s we've had the technology to generate energy without releasing greenhouse gases. I wish more people knew about the harms caused by climate change because maybe if they were they'd be more interested in preventing them.
Yes, for many swaths and types of traditional agriculture and fishing it will be doom, but this conversation isn’t about local ecosystem but global food production vs population growth.
Food production was never a problem, supply and management is.
While nearly half of all habitable land is used to some extent as agriculture, the total amount of land in active cultivation has actually been declining since the early 2000's and we currently abandon more farmland every year than we clear forest or convert to agriculture. Between 1992 and 2020, ~ 7% of all cropland was effectively 'abandoned' and much of the production capacity in the west is actually intentionally kept from being fully planted in order to control against overproduction of cereal crops which in the past has been justified by arguing that this control is necessary to prevent market crashes when distribution networks cannot absorb the full capacity of a harvest.
Globally, there are about a billion acres, 400ish million hectares, ~ about half the size of Australia, which sits unused according to FAO satellite and other observables datasets.
About half of the abandonment not due to cultivability at the simplest level, but rather that of transportation of the crops to market or of access to workforce (labor or equipment) to the land. Smaller, more distant crops without significant mechanization simply cannot compete at the prices possible through mechanization. With a lack of access to global niche markets and the higher prices for, say, premium organics, many successive generations of farming families have simply moved to town and left the land sitting, unused.
The other ~ half of abandoned land is because of degraded production capacity through mismanagement; either through over-application of petrochemical fertilizers instead of crop rotation, or through mechanized tilling without careful erosion management. Many farms have neither the time nor the resources (or in the case of large industrial operations the long-term financial foresight on the part of management) to engage in multi-year regenerative practices necessary to reestablish the soil mycostructure and probiotic ecosystems necessary to recover productivity.
However, if demand were to rise sufficiently and if production instead of distribution was the driving force behind food scarcity, we do indeed have arable land reserves which do not require further destruction of uncultivated wilderness to meet a growing demand.
There is actually an inverse relationship to land productivity at scale; the larger farms do extract more gross tonnage of product at lower costs of per-unit equipment and labor, but actually those operations significantly underproduce volumes of harvestable food if measured in 'per unit of land' instead of labor hours. Fields with multi-level, interconnected plant communities significantly overproduce in terms or total volume. This has been demonstrated in nearly every place on earth using very simple techniques that have varied names and different approaches to marketing, but are all very much the same thing: call it Fukuoka's "One Straw Revolution", Bill Mollison's "Permaculture", Historic Food Forests in Africa and the Decca in India, or in the Middle East "Oasis". In the Americas it still is "Three sisters" gardening. These techniques simply are not mechanized and delivering mass volumes of single commodity product into a global distribution network and that's where the difficulty and disconnect between global populations and available nutrition originates.
If there was a technological and market incentives to connect abundant and diverse harvests in rural communities with Bodegas, restaurants, and grocery store chains in the big cities without ten middle-men adding cost for the consumer without improving the product in the least, then half of the land abandonment issue could unwind and small farms could thrive, not by delivering bulk raw indistinguishable commodity to food manufacturing, but by delivering farm fresh produce to kitchens and fruit stalls.
If that were both low-cost for the consumer, and high earning for the farmer while having quality control and assured provenance then the conversation could center around making better use of even less total cropland and restoring wilderness to a near-native sustainable state.
But as it stands now, we're not short on crop land to human population ratio so much as short on effective distribution and incentives for responsible production.
/todays-soapbox
... this is kind of my area of peculiar skill and work. I've tried to steer multinational, multimillion Euro/dollar agriculture operations that produce significant volumes of global "organically produced" harvests in the direction of cooperating with rural and indigenous farming communities in conserving soil health to the benefit of all. That's been a mixed bag, so the forward momentum is with the local rice production in rural Yamagata. Same objectives, more cooperation and long term planning.
The power is yours.
Until the Boomers finish ageing out and GenZ/A grow up to take the reins, the status quo stays
https://en.wikipedia.org/wiki/2025_New_York_City_mayoral_ele...
Longer. Nuclear power tech was pretty good in the 60s (outside of the Soviet Union).
We just aren’t applying it fast enough for terrible & lazy reasons.
If only we were just debating why/who! Thanks to Social Media, filter bubbles, and “alternative facts,” we are back to debating whether it is actually even happening or not.
https://www.aims.gov.au/monitoring-great-barrier-reef/gbr-co...
This doesn't mean everything is fine, but it is doing way better than 2017.
Bleaching is not death of the coral, it is the expulsion of algae (typically in high temperatures). The coral can find a different species of algae, or the algae can return once temperatures drop.
There are corals living in regions of the ocean with different temperatures, so it is not that high temperature alone would kill all coral, but populations adapted to a given region (like north vs south GBR) are being affected by the speed of the changes.
Was in central GBR this year, can't say I'm super impressed but not sure how I should set my expectation
Typically the biggest change in diversity is due to cyclones which kill of the delicate and fast-growing corals like staghorns, which are also the fastest to grow back.
Because it’s nice to say these things in Sentiment, until you see past the naïveté to see human lives are what cause the wear and extraction on the environment. Humans live, eat, shit in, consume their environment for their lives.
How many humans are worth restoring the reef for you? And would you sacrifice your own friends and family?
You don’t need to sacrifice humans, you need humans to behave different. Do you know the energy requirements that go into war? The chemical, carbon and physical changes to the ocean from all we do?
We don’t need to kill more humans, we just need to stop being fucking idiots for a few hundred years.
So don't straw man please into changing the focus into war because you're uncomfortable. I can see I struck a chord - would you agree you're shifting onto a straw man? And sounds a defensive retort to then reduce my argument to absurdity to dismiss it and invalidate it.
Why should I engage your straw man? Are you uncomfortable? I'm not - but why would I engage you if you failed to demonstrate you heard me. edit: if you're going into an emotionally hostile state, I refuse to take on the emotional labor of being your emotional processing for you - we can agree to mutually disengage.
You responded with Ad Hominem, which is fundamentally intellectually dishonest - and then accused me the exact thing you're doing.
This is the only planet we'll ever meaningfully have and we're killing it for "eternal" growth.
Thank you for your attention to this matter.
Anecdotally I was also there around 2006/2007 - somewhere near Cairns - and the part I saw was esentially dead, not just bleached. It really depends on where you go.
Btw since many in this thread mention ocean warming I want to mention that after having followed this for many years, and observed changes first hand in different parts of the world, my conclusion is that the main factor is direct human influence, not something more abstract like global warming. Especially water pollution as a result of agriculture, unchecked population growth and tourism.
One of the problems is all the people who say they love the reefs want to go where the reefs are still intact, after other parts have already been destroyed. Which then puts even more pressure on those last remaining healthy reef systems. Just talk to divers and listen to the exotic locations they travel to these days. I think many aren't even aware they're part of the problem. Or maybe they subconsciously shift the blame. Reefs are usually healthiest where there are no or very few people around.
The good news is you don't have to be an expert in geoscience to see the connection isn't as simplistic as many assume. Look at the data instead of having preconceived ideas. As an example, when you look at sea temperature data for many of the areas worst affected by coral death in recent decades (Maldives, Seychelles, parts of the Caribbean) you will see they have only seen moderate or even no temperature rise, while many other regions have seen more dramatic rise in local sea temperature and yet have healthier coral.
The fact that the GBR in Australia has seen temperature rise and coral death does not necessarily mean that there is a direct causation or even that it's the main cause. Have you considered other causes play a role?
Edit - The article makes Okkef's point, I just missed it.
> Fragments from different species and even different animals of the same species did not fuse together, and so did not nurse the bleached piece back to health.
I find it strange that the first observance of this was a year ago, especially given how rapidly it occurs. Coral bleaching has probably been studied since the 80s when major events started being noticed. If Stephen Palumbi is reading this, I would love to read why you think it took so long.
edit: I would wager this is only the first published observance.
Conways game of life.
Only if you've never talked to anyone remotely involved with propagating coral, including those in the saltwater fish-tank community!
This is literal, partly how the guy down the street, at your local saltwater aquarium shop, keeps supply in stock. This is grafting/cloning from fragments, boring coral propagation, widely done for many decades. It only works very quickly for some coral though (there are over 1000 known).
Nobody involved with any of this consulted a marine biologist with a rudimentary understanding of coral, or the guy propagating it for a living down the road.
How did I know this? I did a report on coral when I was a kid.
> Nobody involved with any of this consulted a marine biologist with a rudimentary understanding of coral
Hmm.
> Stephen Palumbi: Jane and Marshall Steel Jr. Professor of Marine Sciences, Professor of Oceans and of Biology
https://profiles.stanford.edu/stephen-palumbi?releaseVersion...
You sure he doesnt have even a rudimentary understanding of coral? Did you read the paper? I'm going to assume the marine biologist publishing papers has at least some idea on corals, unless give a good reason to doubt it.
More intelligent individuals should look more into this field.
New age movement, claim everything on earth is actually a hologram of the universe, experiencing itself.
So perhaps, just being in close proximity with another coral, the hologram frequency was now more in tuned.
I am just glad coral can repair themselves.
Thumbs up to the researcher.
Cells are complex organisms and contain programming in their nature so we can more easily trace and understand its reasons
A frequency is something a lot more raw than a cell
"programming in their nature" means they have a range of frequency, like a radio? perharps.
Nevertheless, thumbs up to the researcher. Positive vibes.
Do you believe only experts can contribute to discussions and ideas? Are you afraid of sounding "dumb"?
No question/idea is stupid and it's okay to be wrong or to learn something by putting yourself out there!
Do you mean to say that pseudoscience topics are perceived negatively?