Invasive Species

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DNA Unlocks Dirty Secrets of Blue Catfish Diets

Wednesday, October 12th, 2016

by Kristen Minogue

Large blue catfish held on boat by scientist.

Blue catfish SERC biologists dubbed “Megalodon,”  which they tracked moving almost 60 miles along the Patuxent River. (Brooke Weigel/SERC)

White perch, menhaden and darters: These are just a few favorite foods of Maryland’s invasive blue catfish, according to a new study from the Smithsonian Environmental Research Center (SERC). They’re also known to gorge themselves on larvae of channel catfish—and, occasionally, juveniles of their own kind.

The study, published in the journal Environmental Biology of Fishes, used DNA barcoding to get to the gut of what blue catfish prey on. Blue catfish arrived in Chesapeake Bay in the 1960s, brought by Virginia managers to establish a fishery. They quickly developed a reputation as voracious predators, threatening to devour many popular fisheries and edge out the Chesapeake’s native white catfish. However, to discover how much they could disrupt the ecosystem, marine biologists need to know exactly what they eat. The only way to do that is to look into their stomachs, where the majority of their prey has been reduced to almost-unrecognizable slop.

Rob Aguilar would know: A biologist with SERC’s Fish and Invertebrate Lab, he’s spent the last few years dissecting blue catfish stomachs and analyzing their insides. Click to continue »

Food for Thought: Cooking for Invasive Beetles

Friday, August 12th, 2016

by Emily Li

SERC intern Cole Caceres collects Japanese invasive beetles from hormone trap for his experiment

SERC intern Cole Caceres collects Japanese invasive beetles from a hormone trap for his experiment (Photo: Emily Li/SERC)

Smithsonian Environmental Research Center (SERC) intern Cole Caceres has two passions: science and cooking. He enjoys doing research and adding to the larger body of knowledge, but he hasn’t given up on owning his own restaurant. When he’s not studying nitrogen filtration as a laboratory assistant at the University of California, Davis, he’s probably watching Food Network or frying chicken wings in a sweet soy sauce glaze.

But Caceres found the perfect mix of his interests as an intern with SERC’s Terrestrial Ecology Lab. There, he cooks for invasive Japanese beetles, hoping to help shed light on their dietary preferences so that plant conservation initiatives can be more fully informed—one beetle bite at a time.

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Q&A: Preparing a Safety Net for Native Plants

Monday, July 18th, 2016
Tony Dove in the garden pond in front of the SERC Administration Building

Tony Dove in the garden pond in front of the SERC Administration Building. (Photo: Emily Li/SERC)

by Emily Li

What do we do when native plants lose? About five years ago, the Smithsonian Environmental Research Center and the U.S. Department of Agriculture joined forces to back up seed sources of native plant species, just in case something threatens to wipe them out—but for some species, it looks like we might need them sooner rather than later. Learn more about the partnership and the pros of gardening with natives in this edited Q&A with Smithsonian Environmental Research Center horticulturalist Tony Dove.

Can you tell me about the native sentinel plant species partnership between SERC and the Department of Agriculture?

The Department of Agriculture has a woody plant germplasm conservation center in Beltsville. And what they do is they go around to different locations throughout the country and they collect seeds of various native plants. They grow those native plants in a nursery with the expectation that they will then take those plants and put them out into landscapes in different areas, so that there will always be a seed source for those particular plants if something tragically happens in the area where those plants grew.

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Invasive Ascidians Are a (Potentially Delicious) Recipe for Disaster

Thursday, July 14th, 2016
Christina Simkanin prepares to dive into a marina to survey for ascidians

Christina Simkanin prepares to dive to survey ascidians. (Credit: Natalia Filip, University of Victoria, BC, Canada)

by Emily Li

Smithsonian biologists are on the trail of invasive ascidians. But with roughly 2300 species worldwide, describing these marine filter feeders (also known as “tunicates” or “sea squirts”) for a Most Wanted sign is tricky. Some ascidians are solitary; some are social. Some breed sexually, some asexually. Some, like Botrylloides magnicoecum, form large colonies of what look like octopus tentacles ringed in gold and highlighter blue. Others, like Rhopalaea crassa, resemble a cross between ghostly butterfly cocoons and pastel-colored pencil grips, while Polycarpa aurata is bulbous and mustard-yellow, with navy-blue veins that flare into trumpets.

When they invade new territory, ascidians can leave trails of damage in their wakes—but not always in ways scientists predict. In a new study published in the July issue of Marine Biology, a team of Smithsonian researchers, including marine ecologist Christina Simkanin of the Smithsonian Environmental Research Center (SERC), tracked their invasions across North America.

What they found seemed simple at first: North America’s 26 non-native ascidian species have spread so much they’re now established along nearly 3000 miles of its coastlines. But a few surprises were hiding in the details.

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Citizen Science: How to Hunt for Crabs (And Their Parasites)

Wednesday, June 8th, 2016

by Maria Sharova
SERC citizen science program assistant

Two SERC staff on docks

Maria Sharova (right) sifts through oyster shells in search of tiny mud crabs with intern  Caroline Kanaskie. (Monaca Noble/SERC)

I started working at the Smithsonian Environmental Research Center (SERC) one year ago this month. It had only been two weeks since I graduated from college with a bachelor’s degree in anthropology. Like any recent grad, I was excited and nervous to start my first real job—and, frankly, I wasn’t entirely sure what to expect.

During my first week of work, I was involved with the Chesapeake Bay Parasite Project (a.k.a. the Mud Crab Project), a project that looks at the impact of an invasive, parasitic barnacle called Loxothylacus panopaei (“Loxo” for short) on native white-fingered mud crabs in the Chesapeake Bay. Like most of our volunteers, I’d never heard of either of these organisms, I had no idea why the project mattered, and I’d never been involved in any kind of ecology research before. I had no idea Loxo was able hijack a mud crab’s reproductive system, forcing them to nurse parasite larvae instead of crab larvae. Nor had I ever searched through crates of oyster shells looking for mud crabs the size of a quarter or smaller, as our volunteers were about to do. But in no time at all, I’d become an experienced mud crab finder!

Maria’s Pro Tips for Citizen Scientists

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Top 12 Highlights of 2015: Arctic Sailing, Cownose Rays and an Orchid Showdown

Thursday, December 31st, 2015

by Kristen Minogue

It’s been another wild year at the Smithsonian Environmental Research Center. We sent a sailboat to the Arctic, pitted our orchids in a showdown against the Hope Diamond and discovered a couple new species. And somewhere along the way we celebrated the center’s 50th anniversary. Scroll below for the 2015 #YearInReview, a collection of the top 12 stories, journeys and biggest surprises of 2015.

Image: Cownose Rays (Credit: SERC/Laura Patrick)

Cownose Rays (SERC/Laura Patrick)

Exploring the Ocean

Totes Adorbs! Cownose Rays Take Internet
These marine heartthrobs have earned a top billing. Besides making a 900-mile migration every year, which SERC marine ecologists are tracking with acoustic tags, the kite-shaped rays (whose mouths are stretched so that they seem to be wearing a perpetual smile) also won a Twitter #CuteOff in September.

What Does Life in the Ocean Sound Like?
Postdoc Erica Staaterman listens to the ocean for a living. Often seen as a silent landscape broken only by whale or dolphin songs, Staaterman is helping uncover a wealth of noise from the ocean’s hidden creatures. She shared some of the recordings with us in this edited Q&A.

Cruising the Arctic’s Forgotten Fjords
Ocean acidification researcher Whitman Miller sent one of his CO2-monitoring devices on a 100-day journey to the Arctic. Its mission: Venture to some of Greenland’s never-before-seen fjords and discover how melting glaciers are changing the water. And do it all in a small, 42-foot sailboat. Click to continue »

Phragmites vs. Climate Change: Invasive Reed Better at Taking Up Carbon

Tuesday, December 22nd, 2015

by Kristen Minogue

Image: Josh Caplan holds Phragmites. (Credit: Tom Mozdzer)

Ecologist and lead author Josh Caplan holds a Phragmites plant at the Global Change Research Marsh. Invasive Phragmites can grow up to 15 feet tall. (Thomas Mozdzer)

One of the Chesapeake’s least favorite invaders could end up being an unlikely savior. The invasive reed Phragmites australis, a plant that has exploded across Chesapeake wetlands in the last few decades, is also making those wetlands better at soaking up carbon, ecologists from the Smithsonian Environmental Research Center (SERC) and Bryn Mawr College discovered in a new study.

The common reed, better known as Phragmites australis, grows in dense clusters up to 15 feet tall. North America has several native strains that have co-existed peacefully with many other native plants for at least 30,000 years. It is the invasive strain that arrived from Eurasia in the 1800s that has scientists and environmental managers worried. Eurasian Phragmites grows taller and denser than North American Phragmites, crowding out many smaller plants, and blocking access to light and nutrients. These changes in plant community have a ripple effect on animals that rely on wetlands for habitat.

“The fish communities, the insect communities, the soil and invertebrate communities, all these things change when Phragmites comes in,” says lead author Josh Caplan, a Bryn Mawr postdoc and visiting scientist at SERC. Often, those changes aren’t for the better. “Phragmites is doing a number to these ecosystems.” Click to continue »

Restrictions in Seaweed Agar-vate Scientists

Thursday, December 17th, 2015
Bivalves from Panama for Dermo disease study

Bivalves from Panama for Dermo disease study

by Heather Soulen

Last week Nature magazine published a news piece about how supplies of agar, a research staple in labs around the world, are dwindling. Agar is a gelatinous material from red seaweed of the genus Gelidium, and is referred to as ‘red gold’ by those within the industry. Insiders suggest that the tightening of seaweed supply is related to overharvesting, causing agar processing facilities to reduce production. Most of the world’s ‘red gold’ comes from Morocco. In the 2000s, the nation harvested 14,000 tons per year. Today, harvest limits are set at 6,000 tons per year, with only 1,200 tons available for foreign export outside the country. In typical supply and demand fashion, distributor prices are expected to skyrocket. As a result, things could get tough for scientists who use agar and agar-based materials in their research.

Agar is a scientist’s Jell-O. Just like grandma used to make Jell-O desserts with fruit artfully arranged on top or floating in suspended animation within a mold, scientists use agar the same way. Bacteria and fungi can be cultured on top of nutrient-enriched agar, tissues of organisms can be suspended within an agar-based medium and chunks of DNA can move through an agarose gel, a carbohydrate material that comes from agar. Agar and agar products are the Leathermans of the science world.

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All About That Base…Pairs: Using DNA Barcoding to Identify Fish Gut Contents

Tuesday, November 10th, 2015

by Heather Soulen

Rob Aguilar takes photos of all DNA barcoding reference specimens collected in the Chesapeake Bay

Rob Aguilar takes photos of all DNA barcoding reference specimens they collect in the Chesapeake Bay

Rob Aguilar of SERC’s Fish and Invertebrate Ecology Lab co-authored a DNA barcoding paper this past September in the journal Environmental Biology of Fishes. Rob spoke with us about his paper and the DNA barcoding work going on in the Fish and Invertebrate Lab. While the term DNA barcoding may seem difficult to understand, it’s easiest to think about it as a uniquely identifiable species level code.

Click the sound file below to listen to the interview.

Additional barcoding details are available in the full podcast transcript.

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Remembering Hurricane Katrina by Studying Marshes of the Future

Friday, August 28th, 2015

by Heather Soulen

The Need for Healthy Marshes

Ten years ago, on August 28, 2005, Hurricane Katrina nicked south Florida and entered the heat-charged waters of the Gulf of Mexico, transforming from a Category 1 hurricane into a super-charged Category 5. In the early morning hours of August 29, it ripped through Louisiana and Mississippi. Thousands died, and hundreds of thousands of homes and businesses were destroyed. Today, much of the Louisiana and Mississippi coasts, and its people, are still recovering from the devastation.

When Katrina hit, some coastal marshes east of the Mississippi River lost approximately 25 percent of their area. In the decade that followed, salt marshes and wetlands in Louisiana have continued to disappear in some places, but not others. The scientific community soon zeroed in on keeping marshes healthy, since, as one scientist remarked “A healthy marsh is pretty resilient, A stressed marsh – storms will physically break the marsh down.” Marshes and wetlands are ecologically and economically important ecosystems. During storms they act like buffers, reducing storm surge and flood damage, but only if they’re healthy. The question is, what factors make a marsh strong or weak?
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