It’s no secret that Florida has a snake problem. The Burmese python, which can reach up to 200 pounds and stretch to more than 20 feet, first became common in the Everglades in the late 1990s, likely as escaped pets. The snake quickly settled into its new home, breeding and taking down rabbits, bobcats, and other native animals in its path.

Biologists thought the Arthur R. Marshall Loxahatchee National Wildlife Refuge was one place that was safe. But from 2014 through 2016, scientists combed the waters in and around the refuge for environmental DNA (eDNA) — the trail of DNA left behind by an organism in sources such as feces, mucus, gametes, and shed skin or hair. The results suggested that the python’s DNA was, in fact, widespread throughout the refuge.

But interpreting eDNA results can be tricky. Tiny amounts of cross contamination in the field and lab could result in positive detections where animals aren’t present. “You can get these low signals that are either critically important or not reflecting the truth,” says ecologist Caren Goldberg of Washington State University, whose team has developed eDNA tests to monitor for a wide range of amphibians, including the endangered Sierra Nevada yellow-legged frog. In those cases, the eDNA is there, Goldberg says, but the interpretation of what that means can be wrong. Goldberg, for example, cannot control for moose that carry water in their coats from one pond to another, potentially transferring DNA of fish and other species.

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Medium

We’ve had a lot of earthquakes on our planet this year. Maybe you’ve learned about them from the news or felt one shaking up your own neighborhood. Earthquakes can happen in a few different ways.

First, it is important to know a bit about the Earth’s outer layer, or crust. The crust is made of seven big pieces called “plates.” They are about 60 miles thick and sort of float on the molten rock beneath them. That’s what I found out from my friend Sean Long, a geology professor at Washington State University who knows a lot about earthquakes.

These massive plates move very, very slowly—about one or two inches a year. But when plates slip over or under each other, collide or break away, an earthquake happens. Usually, they last just a few seconds but really big quakes can often last anywhere from 10 to 30 seconds.

After a big earthquake, we often feel a bunch of small earthquakes, or aftershocks. They happen as the crust adjusts to its new location, or settles into its new spot on the Earth’s surface. If one of the plates is under the ocean, sometimes an earthquake will trigger a wave called a tsunami. Depending on the earthquake strength, the wave can be massive or even just a few centimeters high.

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Dr. Universe

The rise of wind and solar power, coupled with the increasing social, environmental and financial costs of hydropower projects, could spell the end of an era of big dams. But even anti-dam activists say it’s too early to declare the demise of large-scale hydro.

The International Hydropower Association (IHA)—which represents dam planners, builders, and owners in more than 100 countries—touts dams as a clean technology, but that’s not quite true: Many reservoirs emit substantial amounts of methane, a potent greenhouse gas released by decomposing vegetation and other organic matter that collect in oxygen-poor reservoirs.

A 2016 study in BioScience found that methane emissions from reservoirs constitute 1.3 percent all of global human-caused greenhouse gas emissions, and the highest-emitting reservoirs rival coal-fired power plants⁠. It is commonly assumed that methane emissions occur chiefly in shallow, tropical reservoirs, as if it’s a problem for only a small number of dam projects. But according to John Harrison, a professor at Washington State University’s School of the Environment and one of the study’s authors, “There is strong and growing evidence⁠ that temperate reservoirs can produce methane at rates comparable to those reported from tropical reservoirs.”

Even so, the Intergovernmental Panel on Climate Change, which sets standards for measuring nations’ greenhouse gas emissions, doesn’t include reservoir emissions in its calculations; the IPCC is considering changing that policy next year. Growing understanding of the factors causing reservoir-generated methane could at least guide decisions about siting dams, avoiding places certain to produce high emissions.

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Yale Environment 360

Marc Kramer, an associate professor of environmental chemistry at Washington State University Vancouver, has discovered that one-fourth of carbon within the Earth’s soil is bound to minerals about six feet below the surface. This revelation could lead to new ways to deal with the influx of carbon due to global warming.

Kramer, who made this discovery with help from his colleague Oliver Chadwick, a soil scientist at the University of California Santa Barbara, explained via his study, published in the journal Nature Climate Change, that water dissolves organic carbon and pulls in deep into the soil. There, the carbon is physically and chemically bound to certain minerals.

Kramer estimates that 600 billion metric tons (known as gigatons) of carbon is currently underneath the Earth’s surface — that amount is more than twice the carbon added into the atmosphere since the Industrial Revolution. Most of this carbon is underneath the world’s wettest forests, which unfortunately, won’t absorb as much carbon as atmospheric temperatures continue to rise.

This “major breakthrough” discovery, as Kramer called it, is a starting point for the process of moving atmospheric carbon underground as climate change and global warming progresses. However, there is still major work to be done.

“We know less about the soils on Earth than we do about the surface of Mars. Before we can start thinking about storing carbon in the ground, we need to actually understand how it gets there and how likely it is to stick around,” Kramer said. “This finding highlights a major breakthrough in our understanding.”

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