Climate change will irreversibly force key ocean bacteria into overdrive

September 1, 2015, University of Southern California

Imagine being in a car with the gas pedal stuck to the floor, heading toward a cliff's edge. Metaphorically speaking, that's what climate change will do to the key group of ocean bacteria known as Trichodesmium, scientists have discovered.

Trichodesmium (called "Tricho" for short by researchers) is one of the few organisms in the ocean that can "fix" atmospheric nitrogen gas, making it available to other organisms. It is crucial because all life—from algae to whales—needs nitrogen to grow.

A new study from USC and the Massachusetts-based Woods Hole Oceanographic Institution (WHOI) shows that changing conditions due to could send Tricho into overdrive with no way to stop—reproducing faster and generating lots more nitrogen. Without the ability to slow down, however, Tricho has the potential to gobble up all its available resources, which could trigger die-offs of the microorganism and the higher organisms that depend on it.

By breeding hundreds of generations of the bacteria over the course of nearly five years in high-carbon dioxide ocean conditions predicted for the year 2100, researchers found that increased evolved Tricho to work harder, producing 50 percent more nitrogen, and grow faster.

The problem is that these amped-up bacteria can't turn it off even when they are placed in conditions with less carbon dioxide. Further, the adaptation can't be reversed over time—something not seen before by , and worrisome to marine biologists, according to David Hutchins, lead author of the study.

"Losing the ability to regulate your growth rate is not a healthy thing," said Hutchins, professor at the USC Dornsife College of Letters, Arts and Sciences. "The last thing you want is to be stuck with these high growth rates when there aren't enough nutrients to go around. It's a losing strategy in the struggle to survive."

Tricho needs phosphorous and iron, which also exist in the ocean in limited supply. With no way to regulate its growth, the turbo-boosted Tricho could burn through all of its available nutrients too quickly and abruptly die off, which would be catastrophic for all other life forms in the ocean that need the nitrogen it would have produced to survive.

Some models predict that increasing ocean acidification will exacerbate the problem of nutrient scarcity by increasing stratification of the ocean—locking key nutrients away from the organisms that need them to survive.

Hutchins is collaborating with Eric Webb of USC Dornsife and Mak Saito of WHOI to gain a better understanding of what the future will look like, as it continues to be shaped by climate change. They were shocked by the discovery of an evolutionary change that appears to be permanent—something Hutchins described as "unprecedented."

"Tricho has been studied for ages. Nobody expected that it could do something so bizarre," he said. "The evolutionary biologists are interested in it just to study this as a basic evolutionary principle."

The team is now studying the DNA of Tricho to try to find out how and why the irreversible evolution occurs. Earlier this year, research led by Webb found that Tricho's DNA inexplicably contains elements that are usually only seen in higher .

"Our results in this and the aforementioned study are truly surprising. Furthermore, they are giving us an improved, view of how will impact Trichodesmium and the vital supplies of new it provides to the rest of the in the future." Webb said.

Explore further: Atmospheric CO2 likely altering ocean foodchain, research says

More information: Irreversibly increased nitrogen fixation in Trichodesmium experimentally adapted to elevated carbon dioxide, Nature Communications 6, Article number: 8155 DOI: 10.1038/ncomms9155

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1.5 / 5 (24) Sep 01, 2015
More assclownery.
4.1 / 5 (26) Sep 01, 2015
More assclownery.

more desperate defense of delusion from someone with no scientific knowledge or even a pretense of interest in scientific knowledge.
1.5 / 5 (15) Sep 01, 2015
Oh... the ignorant AGW Chicken Littles must be hungry.
1.6 / 5 (14) Sep 01, 2015
I wonder how they survived in the past:


3 / 5 (8) Sep 02, 2015
More assclownery.

Yes its you commenting here ;)
3 / 5 (8) Sep 02, 2015
Oh... the ignorant AGW Chicken Littles must be hungry.

By the looks of it you look pretty starved, haven't had your peanuts today ? c'mon monkey you know the rule, you gotta work for your peanuts ;)
3 / 5 (8) Sep 02, 2015
I wonder how they survived in the past:


lots of little things you wondering about in your strange little mind, just worry about getting that peanuts though ;)
2.3 / 5 (3) Sep 04, 2015
Well, climate change has certainly sent the AGW Chicken Little parasites into overdrive.
3.6 / 5 (5) Sep 09, 2015
It's a damn shame climate change is so polarized. IMO both camps are at the furthest extremes and I believe the truth will eventually be found closer to the middle. There is so much we don't know and the complexities are so vast all we can do is speculate as the the actual impact of mans effect on the planet. I believe man is certainly having an impact on the environment on the environment and when possible we should curb our thirst for energy and resources, but we should not cripple ourselves trying to force change faster than our species can reasonably adapt. Improving our ability to harness energy from renewable resources and inventing new technology's to harness energy is a must. However, all the money and legislation in the world cannot make it happen overnight.

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