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For Wetland Plants, Sea-Level Rise Stamps Out Benefits of Higher CO2

Wednesday, May 18th, 2022

Beneficial Effects of Rising CO2 for Plants Disappear Under Flooding, 33-Year Field Experiment Reveals

by Kristen Goodhue

Translucent, open-top chambers dot a grassy wetland under a golden-pink sunrise. A few tree-covered hills rise up in the background.
Sunrise at the Global Change Research Wetland, a site of futuristic climate research at the Smithsonian Environmental Research Center. These chambers have been growing plants with extra CO2 since 1987. (Credit: Tom Mozdzer)

Wetlands across the globe are in danger of drowning from rising seas. But for decades, scientists held out hope that another aspect of climate change—rising carbon dioxide (CO2)—could trigger extra plant growth, enabling coastal wetlands to grow fast enough to outpace sea-level rise. That helpful side effect is disappearing, they discovered in a new study published May 18.

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Tropical Trees Are Dying of Dehydration Due to Climate Change

Wednesday, May 18th, 2022

Rainforest Trees May Be Dying Twice as Quickly Since the 1980s as a Hotter, Thirstier Atmosphere Dries Them Out

by David Bauman and Kristen Goodhue

A lush green rainforest canopy, with one tall, vine-covered tree jutting up higher than the rest of the tree line
Northeast Australia’s relict tropical rainforests, one of the oldest and most isolated rainforests in the world. (Credit: Alexander Shenkin)

Tropical trees in Australia’s rainforests have been dying at double the previous rate since the 1980s, potentially because of climate change, according to an international study published May 18 in the journal Nature. Researchers found the death rates of tropical trees have doubled in the past 35 years as global warming increases the drying power of the atmosphere.

Intact tropical rainforests are major stores of carbon, absorbing around 12% of human-caused carbon dioxide emissions. But their deterioration reduces biomass and carbon storage, making it increasingly difficult to keep global peak temperatures well below the target 2 degrees Celsius required by the Paris Agreement.

“It was a shock to detect such a marked increase in tree mortality, let alone a trend consistent across the diversity of species and sites we studied,” said lead author David Bauman, a tropical forest ecologist at the Smithsonian Environmental Research Center (SERC) and the University of Oxford. “A sustained doubling of mortality risk would imply the carbon stored in trees returns twice as fast to the atmosphere.”

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Large herbivores and large carnivores downsize, as human activity disrupts longstanding trend

Thursday, May 5th, 2022

A pattern that existed since the age of dinosaurs is now disappearing—with profound implications for ecosystems

by Christian Elliott, Northwestern University

A brown bison grazes on a patch of grass, surrounded by grassy mountains in the background
American bison in Yellowstone National Park, Wyoming. Bison are just one example of a large herbivore at risk of extinction, dragging the average size of all herbivores down. (Credit: Frank Schulenburg, CC-BY-SA-4.0)

Sitting on couches at an Airbnb in Montreal for the 2018 Marine World Conference, Jon Lefcheck, the Coordinating Scientist for the MarineGEO program at the Smithsonian Environmental Research Center, and his colleagues started tossing around the sort of questions scientists do in their free time. Questions like, is there a general pattern between what animals eat and how big they are?

Four years later, that conversation has culminated in a new study in Nature Ecology & Evolution, with the most comprehensive analysis yet of the relationship between vertebrate animals’ body sizes and their places on the food chain. The study reaches across taxonomic groups, ecosystems and 150 million years of evolutionary history. Humans, they found, are starting to disrupt a longstanding balance.

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Shelley Bennett: What’s “Normal” Eating in a Maryland Forest?

Thursday, April 28th, 2022

by Deva Holliman

Head and shoulders photo of a young woman with red hair standing in a forest. The forest in the background is blurred, so the woman stands out by contrast
Shelley Bennett, head technician of SERC’s Ecosystem Conservation Lab (Credit: Stephen Voss/Smithsonian)

To celebrate Arbor Day this month, we’re taking a closer look at forest research with Shelley Bennett, head technician of SERC’s Ecosystem Conservation Lab. Much of the lab’s efforts focus on immediate threats, like invasive species and rising temperatures. However, a new project seeks to uncover what happens when a forest functions normally—including the insects and microbes that feast on its leaves. Learn more in this Q&A. Edited for brevity and clarity.

Q: To start off, could you talk about the project you’re working on?

Shelley: Sure! I’m working on a project [regarding] the interactions between insects, microbes, and trees in the chronosequence forest plot here at SERC. We’re looking at different age stands of beech, sweetgum and tulip poplar trees….Younger stands tend to have more tulip poplar and sweetgum, whereas older stands start to have beech trees. We’re looking at seedlings, saplings and mature trees of the three species and assessing leaf damage by herbivores and microbes.….We’re also sampling the insect community in a subset of the plots and looking at how the interactions between insects and trees change as forests naturally age.

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A Postdoc Travels Back 40 Years to Uncover New Truths of Forest Fragmentation

Thursday, March 24th, 2022

by Caitlyn Dittmeier, Smithsonian Working Land and Seascapes intern

Selfie of a scientist hiking through a forest, wearing a blue backpack and a white baseball cap
Amy Hruska pauses for a selfie after conducting a songbird survey. (Credit: Amy Hruska)

At 6 a.m., bird songs chime a new day of field work for Amy Hruska, a postdoc with the Smithsonian Environmental Research Center (SERC) and Chesapeake Working Land and Seascapes ecologist. Recording the species for every tweet and chirp she hears for 20 minutes is hard work. But Hruska is more concerned about a looming silence. Since 1970, 1 billion birds have disappeared from North American forests, leading scientists like Hruska to study the effects of habitat loss on local populations.

Forests once covered 95% of the Chesapeake Bay landscape. But after centuries of intensive farming and development, approximately half of that forest has been cleared. The remaining forest exists in insular patches, bordered by croplands, roads and cities. Scientists understand that fragmentation threatens native wildlife, but they know far less about its impacts over a long period of time.

Curious to know more, Hruska launched a new project investigating how changing land use has transformed the Bay landscape over the past 40 years. To do so, she’s revisiting the same forest patches that SERC researchers studied decades ago.

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“Portfolio Approach” Can Help Protect Restorations From Extreme Climate

Wednesday, March 9th, 2022

by Kristen Goodhue

Two scientists in the water. One kneels beside a manmade rock ball for oyster restorations; the other stands with a clipboard.
Chela Zabin, a SERC marine ecologist, and Thomas Abbott, biologist with the Univ. of California, Davis, check oysters at a restoration in Hayward, San Francisco Bay. (Credit: Geana Ayala/Univ. of California, Davis)

California is no stranger to extreme events. Record-breaking wildfires or heat waves make headlines nearly every year. But in the winter of 2017, another type of extreme devastated underwater life: A series of “Pineapple Express” storms from Hawai’i created extreme rainfall not seen since the state began keeping records in 1895.

“Several atmospheric rivers came and dumped water on the Bay area,” said Chela Zabin, a marine biologist at the San Francisco branch of the Smithsonian Environmental Research Center (SERC) and lead author of a new study on climate extremes.

“For Northern California, 2017 was the wettest winter on record,” said Andy Chang, a SERC biologist and coauthor. “Given our changing climate, record-breaking, once-in-a-lifetime wet years like 2017 are now projected to occur much more often.”

The downpours wreaked havoc on an oyster and eelgrass restoration site that Zabin, Chang and a team of ecologists had been working on since 2012, as part of the San Francisco Bay Living Shorelines Project. The water’s saltiness plummeted to five parts per thousand—a level Olympia oysters can withstand for days, but not months. When the team checked the restoration later in the spring and summer, not a single oyster had survived. However, all was not lost. The following fall, oysters began growing there again naturally. New oyster larvae had drifted into the barren restoration, likely from more central parts of the bay that were not as affected by the extreme rainfall.

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The Perplexing Case of the Peppermint Shrimp

Thursday, February 10th, 2022

How the appearance of a nonnative shrimp in the Chesapeake unearthed a 160-year-old naming mystery

Side-by-side photos of two peppermint shrimp against a black background. One has red stripes running only lengthwise down its body, and one has perpendicular red stripes.
Left: Peppermint shrimp Lysmata vittata found in Chesapeake Bay, now considered the Bruce Clade or “true” Lysmata vittata. Right: Peppermint shrimp found in Singapore, once considered Lysmata vittata. The criss-crossing stripes mark it as belonging to the Rauli Clade, possibly a different species. (Credit: Rob Aguilar/SERC and Arthur Anker)

by Kristen Goodhue

It seemed like such an innocent catch: two peppermint shrimp, netted in the lower Chesapeake Bay during the 2013 Blue Crab Winter Dredge Survey. But their discovery would send Smithsonian biologist Rob Aguilar spiraling down a rabbit hole of century-old field notes, museum fires and World War II bombings. In a new study, Aguilar and SERC’s Fisheries Conservation Lab finally unraveled a taxonomic knot over a century in the making.

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Biodiversity Makes Reefs Tick—But It Needs Big Players

Wednesday, February 2nd, 2022

by Kristen Goodhue

Underwater photo of silver fish swimming over a reef, with orange, pink, brown and white coral.
A school of yellowtail kingfish (Seriola lalandi) at Lord Howe Island in Australia. The presence of large fish like yellowtails can help keep ecosystems healthy and productive, a new study found. (Credit: Rick Stuart Smith, Reef Life Survey)

Three thousand reefs. (Technically 3,040 reefs, for those who like precision.) That’s how many underwater sites scientists and volunteers poured over in the latest effort to uncover how much biodiversity matters for reef health.

The answer: Quite a lot.

Scientists have known for years that diverse fish communities help ocean ecosystems flourish, even when facing rising temperatures and climate change. But the latest study, published in Nature Communications, reveals it’s about more than the numbers. Which species call a reef home can matter just as much as how many there are. And that holds especially true when it comes to large predator fish.

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Out of the Ballast Tank & Into the Waters, Part 3: How The Supply and Demand Faucet Can Fight Invaders

Wednesday, December 8th, 2021

by Marissa Sandoval

Photo taken from onboard the deck of  a massive red cargo ship. The ship juts out into the ocean, with no land in sight. A fountain of ballast water arcs out the right side of the ship.
A cargo ship purges its the ballast water from its hull into the ocean. (Credit: Tim Mullady/SERC Marine Invasions Lab)

This is the final article in a 3-part series about ballast water. Part 1 provided a brief history of ballast water and its accompanying invasive species threats. Part 2 illustrated how scientists from the Smithsonian Environmental Research Center (SERC) are researching technology to prevent invasions and keeping an eye on current ones. This article shows how SERC scientists are working to predict vulnerable spots for ballast water invasion, using shipping networks and commercial trade information.

They say you can never step into the same river twice, since the water’s always running. The same could be said about waters on the shore. Not only do currents sweep the waves to and fro, but new seawater is also constantly being introduced from the ballast tanks of globetrotting ships.

It’s estimated that foreign ships discharge over 180 million metric tons of ballast water off U.S. coasts each year, according to the National Ballast Information Clearinghouse (NBIC). In each ton comes a chance for aquatic critters from foreign ports to invade new shores.

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Ocean Plastic Is Creating New Communities of Life on the High Seas

Thursday, December 2nd, 2021

Coastal Organisms Thrive on Floating Plastic Debris in the “Great Pacific Garbage Patch”

by Kristen Goodhue

Watch: Marine biologist Linsey Haram describes how she studies life floating on plastic pollution that nonprofits and citizen scientists collect from the Pacific Ocean.

Coastal plants and animals have found a new way to survive in the open ocean—by colonizing plastic pollution. A new commentary published Dec. 2 in Nature Communications reports coastal species growing on trash hundreds of miles out to sea in the North Pacific Subtropical Gyre, more commonly known as the “Great Pacific Garbage Patch.”

Closeup of black cylinder coated in yellow, thread-like hydroids, tiny barnacles and a single light-brown crab

Floating debris with a mix of coastal organisms (the yellow podded hydroids Aglaophenia pluma) and open-ocean organisms (Planes crab and gooseneck barnacles) collected in 2018 by the Ocean Cleanup in collaboration with the Smithsonian Institution. (Credit: The Ocean Cleanup)

“The issues of plastic go beyond just ingestion and entanglement,” said Linsey Haram, lead author of the article and former postdoctoral fellow at the Smithsonian Environmental Research Center (SERC). “It’s creating opportunities for coastal species’ biogeography to greatly expand beyond what we previously thought was possible.”

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