The study, published in the scientific journal Nature Communications, suggests that trichodesmium, a key bacteria in maintaining the ocean’s nitrogen levels, could be triggered into an irreversible and unsustainable growth rate as a result of rising oceanic acidity levels from climate change.
Trichodesmium is found in tropical and subtropical waters, and if it exhibits an unsustainable growth rate the results could be disastrous.
“The reason we care about trichodesmium is that it can do something almost nothing else in the ocean does, which is taking atmospheric nitrogen and turning it into new nitrogen which it then introduces to the ocean food chain,” the study’s lead author, Dr. David Hutchins, told GrindTV. “Over 70 percent of the atmosphere is composed of nitrogen gas, but most organisms can’t get at that nitrogen. Trichodesmium can, and that’s why we’re so worried about it.”
To study the affects of increased acidity on the bacteria, Hutchins and his team placed the organisms in water containing the same acidity level scientists approximate the earth’s oceans will have in 2100 if climate change continues at its current rate.
Over the course of five years, the increased carbon dioxide in the waters forced trichodesmium to ramp up its growth rate. Unfortunately for trichodesmium, it exhibited an evolutionary characteristic Hutchins says has yet to be studied amongst organisms — the inability to down regulate growth rates.
“It’s akin to having your foot stuck on the gas pedal as you hurtle towards a wall,” said Hutchins. “We call it being stuck in the fast lane. That irreversible increased growth rate will eventually eliminate the other nutrients like iron that trichodesmium needs to survive, and could trigger a massive dying off of its numbers. And that could be bad in such a keystone organism.”
Consider this: phytoplankton, some of the oceans smallest organisms, need the carbon from trichodesmium to survive.
Those phytoplankton are the main food source for krill, which happen to be the main food source for the blue whale, the largest animal found anywhere on earth.
If trichodesmium populations plummet, the effect could ripple all the way up the food chain to blue whales. Hutchins suggests that the only way to prevent such a thing from happening is to get atmospheric carbon dioxide levels down immediately.
“I don't think any of us studying marine biology would disagree that we need to start bringing down the levels of carbon dioxide humans put into the atmosphere,” said Hutchins. “But we can’t put it off. It needs to happen now, before we make all kinds of ecosystems of the earth irreversibly affected.”
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