Here's a study that shows how changes in ecosystems are not necessarily a good thing.
For arid, Mars-like Peruvian desert, rain brings death
November 14, 2018
When rains fell on the arid Atacama Desert, it was reasonable to expect floral blooms to follow. Instead, the water brought death. Planetary astrobiologists has found that after encountering never-before-seen rainfall three years ago at the arid core of Peru's Atacama Desert, the heavy precipitation wiped out most of the microbes that had lived there.
When rains fell on the arid Atacama Desert, it was reasonable to expect floral blooms to follow. Instead, the water brought death.
An international team of planetary astrobiologists has found that after encountering never-before-seen rainfall three years ago at the arid core of Peru's Atacama Desert, the heavy precipitation wiped out most of the microbes that had lived there.
"When the rains came to the Atacama, we were hoping for majestic blooms and deserts springing to life. Instead, we learned the contrary, as we found that rain in the hyperarid core of the Atacama Desert caused a massive extinction of most of the indigenous microbial species there," said co-author Alberto Fairen, Cornell University visiting astrobiologist, on new research published in Nature's Scientific Reports.
"The hyperdry soils before the rains were inhabited by up to 16 different, ancient microbe species. After it rained, there were only two to four microbe species found in the lagoons," said Fairen, who is also a researcher with the Centro de Astrobiología, Madrid. "The extinction event was massive."
The core of Atacama rarely, if ever, sees rain. But thanks to changing climate over the Pacific Ocean, according to the new paper, that part of the desert experienced rain events on March 25 and Aug. 9, 2015. It rained again on June 7, 2017. Climate models suggest that similar rain events may take place about once every century, but there has been no evidence of rain for the past 500 years.
The surprise precipitation has two implications for the biology of Mars.
Large deposits of nitrates at the Atacama Desert offer evidence of long periods of extreme dryness. These nitrate deposits are food for microbes, Fairen said.
The nitrates concentrated at valley bottoms and former lakes about 16 million years ago. "Nitrate deposits are the evidence," said Fairen. "This may represent an analog to the nitrate deposits recently discovered on Mars by the rover Curiosity."
Another implication may go back four decades. With this new knowledge, the researchers believe that science may want to revisit the Viking experiments on Mars from the 1970s, which involved incubating Martian soil samples in aqueous solutions.
"Our results show for the first time that providing suddenly large amounts of water to microorganisms -- exquisitely adapted to extract meager and elusive moisture from the most hyperdry environments -- will kill them from osmotic shock," said Fairen.
I read the article in question. No distinction is made in this thread between desert ecosystems that rely on annual deluges and desert ecosystems that have evolved to thrive without any precipitation.
It stands to reason, too, as the organisms had evolved to strip any available moisture out of the environment; when they were suddenly flooded, without having evolved the ability to shutter those water-absorbing mechanisms, they blew up (well probably not explosively, but absorbed too much water to function).
There is also no evidence that these die-offs haven't happened in the past, and it doesn't mean that the ecosystem will definitely collapse, though an 85% loss is spectacular, just that they have been brought to a bottleneck; such a bottleneck has happened with many species whose descendants currently live, and will again.
I am certainly not shocked that an environment filled with highly specialised extremophiles was negatively impacted by conditions so completely opposite to what they evolved to handle; I bet most would react similarly, exposed to the polar opposite of their traditional evolutionary pressure.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein
Arid/Desert adapted microbes do not do too well when it gets wet
That sounds like a much better TITLE to me, and a title that observation that makes sense to anyone.
The study focus on just 6 "ancient" desert/dry climate adapted bacteria/microbes.
I am not too sure if just 6 species of bacteria counts as a whole ecosystem.
Also I am not surprised that during the rain event a different set of bacteria/microbes take over.
And during dry times another set of bacteria becomes more active.
I also have a gut feeling that once the soil goes back to be being super dry and the moisture loving microbes stop out competing the arid loving bacteria.
We will see that "ancient" low moisture adapted microbes will show up in their usual numbers.