Plastic-eating Microbes Won’t Solve Our Ocean Debris Problem
Let’s change it to: Japanese scientists announced last week that they have genetically modified a plastic-eating bacteria that they had discovered previously. With the change, the bacteria are now faster at it. Headlines made it seem like our plastic pollution woes were over.
The world produces more than 40 million metric tons of PET plastic every year and, here in the U.S., less than a third of that gets recycled. At the same time, the amount of plastic floating around in the ocean is growing.
But Ramani Narayan, a university distinguished professor in chemical engineering and materials science at Michigan State University, says that touting plastic-eating bacteria as the solution misses the point.
“It is implied that the technology to break down this PET plastic and similar plastics is the bottleneck in managing PET waste. And that this new enzyme is the breakthrough we have been waiting for,” Narayan said.
That’s just not the case, according to Narayan. There are plenty of cheaper and easier ways to break down and recycle PET; in fact, it’s one of the easier types of plastic to break down. So, industrial scale production of enzymes or genetically-modified bacteria isn’t necessary.
Narayan also dismisses the idea of adding either the original bacteria or the genetically enhanced version to ocean environments to speed the degradation of plastic debris. He calls it irresponsible, and says there would be too many side effects for the ecosystem.
The true challenge, Narayan says, is making sure that plastic waste doesn’t escape into the environment in the first place. And that, he argues, means improving waste processing infrastructure — not nearly as exciting as plastic-eating bacteria.
Want to Survive Climate Change? Start Building Your Social Networks
Forty thousand years ago, a massive volcanic eruption in southern Italy devastated what today is Europe. And yet, the culture of the early humans who lived there persisted. Now, archaeologists say the key was long-distance trade and social networking. And Julien Riel-Salvatore, an associate professor of anthropology at University of Montreal, says that could be an important message for modern humans facing the challenges of climate change.
"What we see is that previously, when Neanderthals were confronted with periods of dramatic climatic change, they appear to have gone extinct or completely abandoned the region, modern humans were able to stick it out somehow," Riel-Salvatore said. "And we think that that's probably linked to the fact that modern humans maintained these networks with a group ... a few hundred kilometers away."
The Search for Extraterrestrial Life Continues: TESS and Mars 2020
On Wednesday, April 18th, NASA launched a science satellite aboard a SpaceX Falcon 9 rocket for the first time. After the launch, SpaceX managed to pull off its signature move, landing the first stage of the rocket booster on a barge.
A bonus feature for space geeks — the barge was emblazoned with the words, “Of course I still love you,” a reference to the work of science fiction writer Iain M. Banks.
The satellite aboard that rocket is called TESS, or Transiting Exoplanet Survey Satellite. Once it reaches its elliptical orbit, it will begin its job of looking for earth-like planets around stars nearest to our own solar system.
“TESS has a search radius of something like 300 light years,” said Jennifer Burt, a Torres Exoplanet Fellow at the MIT Kavli Institute. “In astronomical terms, that’s really nearby, but as far as you and I are concerned, that’s not really a distance you see on your GPS very often.”
TESS’ method is to watch for a dip in the amount of light coming from nearby stars.
“The size of the dip tells you how big the planet is, and the timing between those dips tells you how far the planet is from the host star,” Burt said.
That’s important because if the planet is too close to its star, it’ll be too hot for liquid water to exist. Too far from its star, it’ll be too cold for liquid water. There’s a “habitable zone” where the temperature is just right. Once TESS locates planets in that zone, telescopes on the ground can focus in for a closer look.
Despite TESS’ promise, Burt acknowledges that the satellite has its limitations. TESS can only see planets orbiting around stars in the same plane as earth’s orbit. There’s evidence that such orbits are randomly sprinkled throughout the universe.
“Something like 10 percent of systems should have transits that we should be able to see from earth,” she said. “So, for every one planet that TESS sees transiting around a star, there should be another nine stars that also have planets that aren’t oriented quite right for us to detect them with this method.”
MARS 2020
While TESS is off to explore distant exoplanets, there’s an ongoing search for extraterrestrial life much closer to home.
Scientists are still searching Mars for evidence of life — probably past life, but possibly present. A new rover will head to Mars in 2020, and right now, the science community is hashing out where it will land and where it will focus most of its attention.
But, we’ve already sent rovers to Mars, which have sent back excellent photos. If Mars had life on it, wouldn’t we know it by now?
“If Mars were teeming with life, we would have found it. But, clearly, Mars is not teeming with life,” said Jack Mustard, a professor of earth, environmental and planetary Sciences at Brown University.
Mustard is deeply involved in the process of selecting a landing site and planning the science the next rover will do once it gets there.
“We’ve barely scratched the surface,” Mustard said. “And if I were a microbe living on Mars, I would not be on the surface, I’m telling you. I would be underground.”
Mustard says that signs of life on Mars would most likely be of past life, not present.
“The ground is probably frozen down to a kilometer depth,” Mustard said. “It would be hard to live … near the surface.”
NASA started the process of selecting a landing site for the rover in 2011 and has been taking public input. A working group of scientists has narrowed down the sites from more than 30 proposals to just three finalists. They will hold the final meeting to select the landing site at the end of September.
“[We’ll] really have a detailed science discussion,” he said.
It’s an Alga, It’s a Squid. No, It’s a Fish!
A fossil found in Kansas 70 years ago has been identified as a large cartilaginous fish, like a shark or a ray. That wouldn’t be so noteworthy if the same fossil hadn’t already been identified, twice — first as a green alga, and then as a squid or cuttlefish.
This isn’t the first — nor, in all likelihood, the last — time that a fossil has been misidentified. Another examples inlcudes a fossil that was thought to be a sponge but was actually a land plant, or would-be fungi that turned out to be lungfish teeth, explains Allison Bronson, the graduate student at the American Museum of Natural History who made the latest re-identification.
Bronson points the finger not at improving technology, but at paleontologists stuck in their own bubbles of expertise.
“It’s easy to have blinders on,” Bronson said. “If you only have a hammer, every problem tends to look like a nail.”
In this case, three different sets of scientists looked at the same hexagonal texture in the same fossil and saw three different things. Algae experts saw algae, but with some extra protrusions they couldn’t quite explain. Cephalopod experts saw a cuttlefish bone. And Bronson sees cartilage.
Bronson admits she’s not immune to the hammer-nail effect, noting with some humor that her studies of fossilized shark heads are “pretty niche.” But she and her colleagues used high-tech imaging techniques and did some extra chemical tests to see if their identification would hold up. It did.
Bronson says her team is pretty confident they’ve gotten the right answer this time, but doesn’t rule out the possibility of revisions.
“I sure would be disappointed,” Bronson laughed.
