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In San Francisco, One Wet Winter Can Switch Up Bay’s Invasive Species

Thursday, December 7th, 2017

Winter rains make Bay less salty, knocking back some invaders

by Kristen Minogue

Man in sunglasses on rocky beach

Marine ecologist Andrew Chang tracks invasive species in California, and is discovering ways climate change and extreme weather can alter the playing field. (Credit: Julia Blum)

For many Californians, last year’s wet winter triggered a case of whiplash. After five years of drought, rain from October 2016 to February 2017 broke more than a century of records thanks to a series of “Pineapple Express” storms, referring to atmospheric rivers that ferry moisture from Hawaii to the Pacific Coast. In San Francisco Bay, Smithsonian Environmental Research Center biologists discovered a hidden side effect: All that freshwater rain can turn the tables on some of the bay’s invasive species.

“As you get wetter and wetter, there are fewer and fewer [marine] species that can tolerate those conditions,” said Andrew Chang, lead author of the new study published Dec. 7 in Global Change Biology.

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What Changes When You Warm the Antarctic Ocean Just One Degree? Lots.

Thursday, August 31st, 2017

Morning commute in Antarctica. (Photo: Lloyd Peck)

Morning commute in Antarctica. (Photo: Lloyd Peck)

After warming a natural seabed in the Antarctic Ocean by just 1° or 2° Celsius, researchers observed massive impacts on a marine assemblage, as growth rates nearly doubled. The findings of what the researchers call the “most realistic ocean warming experiment to date” reported in Current Biology on August 31 show that the effects of future warming may far exceed expectations.

“I was quite surprised,” says Gail Ashton of the British Antarctic Survey and Smithsonian Environmental Research Center. “I wasn’t expecting a significant observable difference in communities warmed by just 1°C in the Antarctic. I have spent most of my career working in temperate climates where communities experience much greater temperature fluctuations and wasn’t expecting such a response to just 1°C of change.”

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Scientists Turn Up the Heat on Herbivores and Their Food

Friday, July 28th, 2017

By Joe Dawson

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Japanese beetles make a meal of evening primrose leaves (Credit: Dejeanne Doublet/SERC)

Plants can seem pretty boring. They just sit there, after all. Sure, they can be pretty; they can make us sneeze. But what else do they do? A lot, it turns out. They are able to shift their own water and energy resources from leaves to stems to roots and back, grow tall or stay low and bushy, defend themselves through biological warfare, or warn their neighbors of danger. When doors get blocked, plants have ingenious ways of sneaking out through windows.

What, then, will plants do when humans spread a carbon dioxide blanket over the planet, warming it by burning fossil fuels? Research scientist Nate Lemoine of Colorado State University, with John Parker of the Smithsonian Environmental Research Center (SERC) and others, decided to investigate one such relationship with an experiment on the SERC campus in 2013 and 2014. Click to continue »

Time Travel, with Trees

Monday, July 10th, 2017

by Joe Dawson

Looking at the Kirkpatrick Marsh on the Rhode River, a time machine is not the first thing that comes to mind. Tall grasses dominate the landscape, with vertical PVC pipes popping up here and there and octagon-shaped chambers rising out of the wetland every ten paces or so. Take a step off the walkway, and you might lose a shoe. But 5 experiments on the marsh are designed to take sections of the marsh into the 22nd Century, and the marsh has been dubbed the Global Change Research Wetland, or GCReW. The expertise that GCReW scientists have in simulating the future brought National Museum of Natural History scientists here to mirror the past.

Rich Barclay and Scott Wing are paleobotanists at the National Museum of Natural History. Paleobotanists are the ones who stare at leaves in Jurassic Park and say, “Alan, these plants haven’t been seen since the Cretaceous Period,” as everyone else stares at brachiosauruses. Ancient plants are their bread and butter, and for Wing and Barclay, the bread is toasted and the butter melty. They study one of the warmest periods in the last 100 million years, the Paleocene-Eocene Thermal Maximum (PETM). During this period, global temperatures skyrocketed, increasing by 10-15 degrees Fahrenheit. By looking at plants that grew during this time, they hope to learn more about what Earth was like 55 million years ago.

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Large growth chambers being built around newly-planted ginkgo trees on the SERC campus (Credit: Rich Barclay)

Barclay, Wing, and colleagues have started an experiment on the Smithsonian Environmental Research Center’s (SERC) campus that grows ginkgo trees in varying carbon dioxide levels. They hope to study these trees and compare them to fossil specimens to learn about the past. Click to continue »

The Environmental Cost of Shoreline Hardening

Wednesday, June 21st, 2017

New study shows hardened shorelines may mean fewer fish and crustaceans. 

by Ryan Greene

A split image with a wooden bulkhead on the left and a rocky riprap revetment on the right.

A new SERC study shows that both bulkheads (left) and riprap revetment (right) are associated with lower abundance of several species of fish and crustaceans in the Chesapeake Bay and the Delaware Coastal Bays. Credit: SERC

For decades, ecologists have suspected that hardened shorelines may impact the abundance fish, crabs, and other aquatic life. But now they have evidence that local effects of shoreline hardening add up to affect entire ecosystems. A new study by scientists at the Smithsonian Environmental Research Center (SERC) shows that more shoreline hardening means fewer fish and crustaceans in our waters.

Given the predictions for the coming years (i.e. rising seas and more of us living on the coast), this finding is a cause for concern. Many people will likely try to protect their land from flooding and erosion by armoring their shorelines with vertical retaining walls (bulkheads) or large rocks (riprap revetment). But as SERC researchers found in their new paper, published in Estuaries and Coasts, the impact of these hardened shorelines adds up.

Lead author and former SERC postdoc Matt Kornis likens shoreline hardening to littering. While each individual bit of trash isn’t a huge problem, the combined effect can be enormous. Kornis, now a biologist for the U.S. Fish & Wildlife Service, says the same is true of shoreline hardening. Each individual bulkhead or riprap revetment may not be catastrophic, but cumulatively they can contribute to shrunken populations of ecologically—and economically—important species like the blue crab.

“Shoreline hardening can cause loss of habitats important for young fish, like wetlands and submerged vegetation,” Kornis says. “That may be one reason we observed low abundance of many species in estuaries with a high proportion of hardened shoreline.” Click to continue »

Humans Are Short and Trees Can’t Talk

Tuesday, June 20th, 2017

That’s why Uzay Sezen carries a crossbow and liquid nitrogen into the forest with him.

by Ryan Greene

Intern Alex Koure (left) and postdoctoral researcher Uzay Sezen (right) are using a crossbow to get leaf samples from hard-to-reach branches. A fishing line attached to the arrows helps them shake down leaves from the canopy. Credit: Ryan Greene/SERC

Intern Alex Koure (left) and postdoctoral researcher Uzay Sezen (right) are using a crossbow to get leaf samples from hard-to-reach branches. A fishing line attached to the arrows helps them shake down leaves from the canopy. Credit: Ryan Greene/SERC

Uzay Sezen is a new postdoc at the Smithsonian Environmental Research Center (SERC), and he’s on the hunt for good data. Literally.

A researcher holds a crossbow and metal container of liquid nitrogen in a forest.

Uzay Sezen with his crossbow and liquid nitrogen in Harvard Forest. Credit: SERC

With senior scientist Sean McMahon and other members of the Quantitative Ecology Lab, Sezen is embarking on a multiyear study which aims to unveil the genetic patterns of tree growth. Their mission: Find out if tree species present at both SERC and Harvard Forest grow in the same way, and whether there are particular genes they express when they grow. Not only will this help us understand how trees respond to day-to-day changes in sunshine, temperature, and rainfall, but it may provide insight into how forests will react (and already are reacting) to global factors like climate change.

Since about 2009, scientists at SERC have been using metal bands called dendrometers to measure how trees grow (within a hundredth of millimeter!) over years, seasons, weeks, and even days. According to SERC technician Jessica Shue, combining these physical measurements with Sezen’s genetic analysis may help reveal what makes some trees in the forest winners and others losers.

“Now that we can look at the genetics, we can look at a much finer scale at what’s causing some trees to be dominant in the canopy, and others of the same species [to be] stuck in the understory,” she says.

How, though, do you ask a tree which genes it’s using?

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Q&A: Kim La Pierre, Ecosystem Conservation Ecologist

Friday, June 16th, 2017

by Kristen Minogue

Close-up of Kim La Pierre in prairie

Kim La Pierre in Konza Prairie, Kansas, home to one of the first Long-Term Ecological Research (LTER) programs. (Credit: Arjun Potter)

Kim La Pierre does big-picture ecology. The newest senior scientist at the Smithsonian Environmental Research Center, La Pierre is leading the center’s Ecosystem Conservation Lab. But while working on large-scale global experiments, she also delves into the microscopic world of bacteria. In this Q&A, discover how bacteria give certain plants an edge, and how she blends the very large and the very small.

This is the first of three profiles about the young scientists heading SERC’s newest labs. Edited for brevity and clarity.

You’ve done a great deal of work with legumes—plants in the bean and pea family. Can you talk about their weird relationship with rhizobial bacteria?

The [legume] plants and bacteria are in a mutualism where the plants fix carbon into sugar and give it to the bacteria, and the bacteria are able to take nitrogen from the atmosphere and give it to the plants. This is a source of nitrogen that no other plants have access to. Most plants have to take [nitrogen] up from the soil. Because of this mutualism, legumes can get nitrogen from another source, and that often makes them very successful in different, especially harsh environments….

It’s interesting to think about the different legume species, and how good they are at enforcing cooperation from the bacteria. Thinking about the bacteria as not only potentially being beneficial, but [also possibly] cheating the system—trying to take carbon from the plants and not give back as much nitrogen, especially under high soil nitrogen conditions. Click to continue »

Surprising Tree Emissions Show Forests Consume Less Methane Than Thought

Tuesday, May 9th, 2017

by Ryan Greene

White chambers attached to tree trunks. Multi-colored tubes run from the chambers to a black box in the undergrowth.

Methane flux chambers keep track of how much methane a tree trunk releases or consumes. Credit: Pat Megonigal/SERC

Rainbow-colored tubes snake through the undergrowth. White acrylic chambers sit mounted to tree trunks like giant bleached snails. At first glance, it’s not quite clear what the heck is going on. Cryptic as it may seem, these tubes and chambers are the key to a recent study showing that trees in upland forests are capable of emitting the planet-warming greenhouse gas, methane.

Scientists have long considered upland forests to be methane sinks due to the presence of methane-hungry microbes called methanotrophs in their soils. But new research by Pat Megonigal, an ecosystem ecologist who heads up the Biogeochemistry Lab at the Smithsonian Environmental Research Center (SERC), and Scott Pitz, a graduate student from Johns Hopkins, has shown that when it comes to upland forest methane cycling, soil isn’t the only game in town. Trees and their emissions are part of the equation too.

In a recently published study in New Phytologist, Megonigal and Pitz found that trees in upland forests are actually capable of emitting methane through their trunks. This means that some of the methane absorbed by methanotrophs in the forest soils may be offset by tree emissions.

Why, though, does any of this even matter?

When researchers think about global climate change, they need to think about heat-trapping greenhouse gases like carbon dioxide (CO2) and methane (CH4). Specifically, they’ve got to track these gases to see where they’re coming from (their sources) and where they’re getting stored (their sinks). Carbon dioxide receives much of the spotlight (and rightfully so, given its enormous impact on the global climate), but it’s also critical to keep an eye on methane. Although methane stays in the atmosphere for far less time than carbon dioxide, it’s capable of trapping up to 45 times more heat. In other words, methane is a big deal. If temperate forests are consuming less of it than we thought, as Megonigal and Pitz’s research suggests, that could be a big deal too. Click to continue »

Ten Reasons We’re Earth Optimists After 2016

Friday, January 13th, 2017
Dawn Miller in forest

Ecologist Dawn Miller surveys trees in a SERC forest. (SERC)

by Kristen Minogue

The Smithsonian has a new resolution for 2017: Earth Optimism. This is the year the Smithsonian is celebrating environmental success stories, and shifting the focus to how we can fight battles to save species and preserve our planet—and win. Despite breaking a wide swath of climate records, 2016 gave us reasons for optimism as well. In our 2016 Year in Review, we’ve pulled out the most encouraging stories and discoveries at the Smithsonian Environmental Research Center from the previous year. Here are the top 10 that make us hopeful about the planet’s future:

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Jekyll or Hyde? The Many Faces of Phragmites

Friday, December 16th, 2016

by Kristen Minogue

Scientist beside a Phragmites experiment on the water.

Pat Megonigal studies the invasive reed Phragmites australis on the Smithsonian’s Global Change Research Wetland.
(Tom Mozdzer)

It’s easy to dislike Phragmites. The invasive brown reed can grow over 15 feet tall and tends to crowd out anything in its shadow. But in the story of global change, Phragmites is a gray character, like Mad Men’s Don Draper, or the enigmatic Professor Snape. Beneath the surface, Phragmites australis—a European reed sweeping over East Coast wetlands—can empower wetlands to grow higher soils and possibly survive rising seas. Biogeochemist Pat Megonigal of the Smithsonian Environmental Research Center (SERC) prefers an analogy from classic literature: Jekyll and Hyde.

“The Jekyll part is that Phragmites helps marshes maintain elevation and keep pace with sea level rise,” he said. “The Hyde part is that they are poor habitat for native plants and animals.”

The latest discovery in Megonigal’s lab could tip things in favor of Mr. Hyde. Phragmites’ deep-growing roots were once thought an advantage that helps wetlands build soil. But those same roots could be disturbing ancient soils deep underground—triggering them to release planet-warming carbon dioxide (CO2).

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