Ecology

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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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Climate Change Could Release Ancient Soil Carbon

Friday, July 1st, 2016

by Kristen Minogue

Blanca with soil core

Blanca Bernal extracts a soil core from a SERC marsh. (Credit: SERC)

Just beneath our feet, there’s a slumbering pool of carbon that has largely been ignored.

Earth’s deep soils store vast reservoirs of carbon centuries to millennia old. Left undisturbed, they can store that carbon for thousands of years longer. But if triggered, those reservoirs could release carbon dioxide (CO2) into the atmosphere, a team of scientists discovered in a new study from the Smithsonian Environmental Research Center.

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Cranking Up the Heat in the “Wetland of the Future”

Friday, June 24th, 2016

by Joe Dawson, SERC research aide

Last fall, while volunteering in a plant lab at George Washington University in D.C., I heard about an experiment that was starting up at the Smithsonian Environmental Research Center (SERC). The project, a global warming simulation in the wetlands surrounding the Chesapeake Bay, was helmed by SERC research ecologist Roy Rich, an ecologist with an engineer’s mindset. I’ve been a wetlands enthusiast since I spotted my first blue Heron as a kid, and global climate change is, in my mind, the most pressing issue humans face today. I was ready to sign up. I met with Roy and asked the same questions I have since answered over and over again since joining the project in November:

Joe Dawson kneels by a control box on marsh

Joe Dawson checks a control box for the underground heating cables that help raise temperature in the marsh plots. (Kristen Minogue/SERC)

“You’re heating up a swamp?” Yes.

“And adding CO2?” Yes.

“In a greenhouse?” No.

“Out in the open?” Yes.

“Umm, how?” Well…

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Geckos and Lemurs and… What? Celebrating Unexpected Pollinators

Monday, June 20th, 2016

by Emily Li

We have a lot to thank pollinators for this National Pollinator Week. Not only do they provide every third bite of food, but they also add $217 billion dollars to the global economy and help support healthy ecosystems. But can we even identify a pollinator when we see one?

Picture pollinators—from fat, sunlit bumblebees hovering lazily from flower to flower, to yellow butterflies flitting among pollen-dusted petals in brilliant flashes of antennae and wing. If you’re feeling especially imaginative, you might think of the delicate, curved beaks of hummingbirds dipped into blossoms larger than themselves. But while bees and butterflies share the limelight, underappreciated pollinators from all walks, wings, and wades of life quietly help to create the next generation of flowering plants.

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Key to Oysters’ Future Lies in Past

Monday, May 23rd, 2016
Oyster midden

Typical American Indian oyster deposit, roughly 1,000 years old. (Torben Rick/Smithsonian)

by John Gibbons

Oysters have provided food for humans for millennia, and play an enormous role in sustaining estuaries around the world. Yet after more than a century of overfishing, pollution, disease and habitat degradation, oyster populations in the Chesapeake Bay and elsewhere have suffered dramatic declines. But for thousands of years,American Indians in the region harvested the shellfish from the Bay sustainably—a discovery published Monday that could offer clues for future oyster restoration.

Little is known about oyster populations prior to the late 1800s. On May 23 a team of Smithsonian scientists and other researchers published the first bay-wide, millennial-scale study of oyster harvesting in the Chesapeake in Proceedings of the National Academy of Sciences. Using fossil, archaeological, and modern biological data, the team was able to reconstruct changes in oyster size from four timeframes: the Pleistocene (780,000-13,000 years ago), prehistoric American Indian occupation (3,200 – 400 years ago), historic (400 – 50 years ago) and modern times (2000 to 2014).

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Biodiversity Protects Fish From Climate Change

Monday, May 16th, 2016

by Kristen Minogue

Fish provide protein to billions of people and are an especially critical food source in the developing world. Today, marine biologists confirmed a key factor that could help them thrive through the coming decades: biodiversity. Communities with more fish species are more productive and more resilient to rising temperatures and temperature swings, according to a new study from the Smithsonian’s Tennenbaum Marine Observatories Network and other international institutions.

The accelerating loss and rearrangement of species all over the globe have troubled scientists and the public for decades. But the question of whether biodiversity offers practical value—for humans and ecosystems—remained controversial. The new study, published May 16 in the Proceedings of the National Academy of Sciences, offers the most thorough proof yet that preserving marine biodiversity can benefit people as much as it benefits the oceans.

“Biodiversity is more than a pretty face,” said lead author Emmett Duffy, director of the Tennenbaum Marine Observatories Network and senior scientist at the Smithsonian Environmental Research Center. “Preserving biodiversity is not just an aesthetic or spiritual issue—it’s critical to the healthy functioning of ecosystems and the important services they provide to humans, like seafood.”

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Acidification and Low Oxygen Put Fish in Double Jeopardy

Tuesday, May 10th, 2016

by Kristen Minogue

Inland silverside with reflection.

Inland silverside (Menidia beryllina) reflected in aquarium. When threatened with low oxygen, fish often swim to the surface, where oxygen is more abundant but predators can more easily spot them. (SERC)

Severe oxygen drops in the water can leave trails of fish kills in their wakes, but scientists thought adult fish would be more resilient to the second major threat in coastal waters: acidification. A new study published Tuesday from the Smithsonian Environmental Research Center (SERC) shows that is not entirely true—where fish are concerned, acidification can make low oxygen even more deadly.

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Coffee, Carbon and Crime: 22 Reasons to Love Trees

Friday, April 22nd, 2016
Dawn Miller in forest

Ecologist Dawn Miller in SERC forest (SERC)

by Kristen Minogue

Friday is Earth Day, and this year it’s all about the trees. The Earth Day Network is on a mission to plant 7.8 billion trees in five years. Trees have enormous power when it comes to protecting the Earth. Scientists at the Smithsonian Environmental Research Center (SERC) have spent decades uncovering the environmental benefits of forests. But trees offer some advantages that are less obvious. Like acting as painkillers. Or improving your morning coffee. Since the holiday falls on April 22, we picked our top 22 things trees do for humanity.  Click to continue »

Amphibian Congregation: Sonic Songs of Spring

Wednesday, March 30th, 2016

by Heather Soulen

Sonic Cacophonies

American Toad (Photo: Tyler Bell)

American Toad (Photo: Tyler Bell)

It’s that time of year when much of the mid-Atlantic is waking up from a long winter’s slumber. Flowers are blooming, trees are budding, ospreys and eagles are nesting, and frogs are calling. Right now, the Smithsonian Environmental Research Center (SERC) is alive with the sonic cacophony of a two amphibians. Spring peepers (Pseudacris crucifer) and American toads (Anaxyrus americanus, formerly Bufo americanus) are shouting mating anthems from every available pocket of water. If you live east of the Mississippi River from Canada to Florida, you’ve likely heard their calls. But which is which? We’ve collected a few sound bites around SERC to help identify each amphibian’s call.

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The Everyday Naturalist: Fishing Spiders

Thursday, February 11th, 2016

by Jan Payne Wilson, SERC Volunteer

Six-spotted fishing spider (Dolomedes triton). Credit: Derek Ramsey

Six-spotted fishing spider, Dolomedes triton. Credit: Derek Ramsey

My dad was uncomfortable around spiders. Today we’d probably say he had a phobia. To deal with it, he found a spider-like creature, the Daddy Long Legs, and learned how benign and beneficial it was. From then on, he could focus on a “good spider” rather than his fear. As a child, I was indoctrinated with the knowledge that a Daddy Long Legs 1) could not bite you and 2) performed good deeds by eating “bad” spiders and other biting, child-frightening insects. Furthermore, they needed our help because they had delicate legs that easily broke off, so we moved them out of dangerous areas and avoided stepping on them. When I was older my father revealed that Daddy Long Legs weren’t actually spiders. Unlike true spiders, they can’t make silk and have neither fangs nor venom. From my father I learned that understanding a creature often changes fear into appreciation and, sometimes, amazement.

On the docks of the Smithsonian Environmental Research Center (SERC), I use my dad’s strategy to help students who either fear spiders or believe the only good spider is a dead spider.  With Daddy Long Legs it’s easy.  But we also have large spiders we don’t see as frequently: fishing spiders.  When you see your first fishing spider, it’s a hard sell to believe she’s got redeeming characteristics. Click to continue »